JP2021173773A - Polarizing film, optical laminate, and image display device - Google Patents

Abstract

To reduce the discoloration of a polarizer when a polarizing film is exposed to a hot and humid environment.SOLUTION: The polarizing film comprises: a polarizer 111; a first decorative layer 112a and a first adhesive layer 113a on one principal surface side of the polarizer; and a second decorative layer and a second adhesive layer or a protective layer 114 on the other principal surface side. The first decorative layer 112a is bonded directly to a peripheral part of the one principal surface without via the adhesive layer, and the first adhesive layer 113a covers the side of the first decorative layer that is opposite to the polarizer and a region of the one principal surface where the first decorative layer is not bonded. The second decorative layer is bonded directly to a peripheral part of the other principal surface without via the adhesive layer, and the second adhesive layer covers the side of the second decorative layer that is opposite to the polarizer and a region of the other principal surface where the second decorative layer is not bonded. The moisture vapor permeability of each of the first decorative layer, the second decorative layer, and the protective film is 1500 g/m2 24h or less when the thickness is 25 μm.SELECTED DRAWING: Figure 1

Description

The present invention relates to polarizing films, optical laminates and image display devices.

An image display device for displaying an image such as a still image or a moving image includes, for example, a window member, an optical film, and a panel member including a display panel. The image display device may further include a touch sensor. Further, in the assembly of the image display device, an optical laminate in a state where the laminated structure excluding the panel member of the image display device is held by the separator may be provided. For example, an image display device can be formed by peeling off the separator of the optical laminate and attaching it to the panel member.

The optical film used in the image display device usually includes a polarizing film. A general polarizing film includes a film-shaped polarizing element and a protective film arranged so as to sandwich each of the main surfaces of both polarizing elements. An adhesive layer may be interposed between the polarizer and each protective film.

Further, in image display devices, there is an increasing demand for thinning and cost reduction.

Patent Document 1 describes a polarizing base layer; a polarizing coating layer coated on the lower surface of the polarizing base layer; an adhesive layer arranged on the upper portion of the polarizing base layer; and on the surface of the polarizing base layer or the polarizing coating layer. We are proposing a polarizing film that includes a light-shielding member that is printed to form a single film. Patent Document 1 describes that the polarizing plate arranged at the top of the display panel is replaced with a polarizing coating layer arranged at the bottom of the cover glass to reduce the thickness of the display panel and reduce the manufacturing cost. There is.

Korean Publication No. 10-2019-0020925 (Claim 1, [0006])

In a typical polarizing film, the protective film is placed on both main surfaces of the polarizer. From the viewpoint of thinning and low cost, it is advantageous to form the polarizing film without using at least one of such protective films. However, in a polarizing film in which at least one main surface side of the polarizer is not protected by a protective film, there may be a problem that decolorization becomes remarkable at the end of the polarizer when exposed to a high temperature and high humidity environment. Became clear.

In the present specification, a polarizing film having no protective film on at least one main surface side of both main surfaces of the polarizing element may be referred to as a protectionless polarizing film.

The first aspect of the present invention is a polarizer and
A first decorative layer and a first adhesive layer adhered to one main surface of the polarizer,
A second decorative layer and a second adhesive layer, or a protective film, which are adhered to the other main surface of the polarizer, are provided.
The first decorative layer is directly adhered to the peripheral edge of one of the main surfaces without an adhesive layer.
The first adhesive layer is formed so as to cover a surface of the first decorative layer opposite to the polarizer and a region of the one main surface to which the first decorative layer is not adhered.
The second decorative layer is directly adhered to the peripheral edge of the other main surface without an adhesive layer.
The second adhesive layer is formed so as to cover a surface of the second decorative layer opposite to the polarizer and a region of the other main surface to which the second decorative layer is not adhered.
The protective film is directly adhered to the other main surface without an adhesive layer, or is adhered through an adhesive layer.
The first decorative layer, the second decorative layer, and wherein each of the protective film, the moisture permeability when the thickness of 25μm is not more than 1500 g ^/ m 2 · 24h, regarding polarization film.

A second aspect of the present invention comprises the above-mentioned polarizing film and at least one of a window member and a retardation film.
The polarizing film includes a first main surface on the viewing side and a second main surface on the side opposite to the first main surface.
The window member is arranged on the first main surface side of the polarizing film.
The retardation film relates to an optical laminate arranged on the second main surface side of the polarizing film.

A third aspect of the present invention comprises the above-mentioned polarizing film and a panel member.
The polarizing film includes a first main surface on the viewing side and a second main surface on the side opposite to the first main surface.
The panel member relates to an image display device arranged on the second main surface side.

A fourth aspect of the present invention relates to an image display device including the above-mentioned optical laminate and a panel member arranged on the side opposite to the visible side of the optical laminate.

It is possible to reduce the decolorization of the polarizer when the protective-less polarizing film is exposed to a high-temperature and high-humidity environment.

It is the schematic sectional drawing of the image display apparatus provided with the polarizing film of one Embodiment of this invention. It is the schematic sectional drawing of the image display apparatus provided with the polarizing film of another embodiment of this invention. It is schematic cross-sectional view of the laminated body (evaluation sample) containing the polarizing film produced in Example 1. FIG. It is a Raman spectrum at four measurement points of a polarizer after the evaluation sample of Example 1 was exposed to a high temperature and high humidity environment for a long time. It is a Raman spectrum at four measurement points of a polarizer after the evaluation sample of Comparative Example 1 was exposed to a high temperature and high humidity environment for a long time.

The protectionless polarizing film is excellent in terms of thinness and cost reduction. However, it has become clear that when the protective-less polarizing film is exposed to a high-temperature and high-humidity environment, a new problem may arise in which decolorization becomes remarkable in the polarizing element (particularly at the end of the polarizing element). In such a decolorization of the polarizer, in a high temperature and high humidity environment, moisture penetrates through the interface between the polarizer and the layer adjacent to the polarizer, or the moisture absorbed by the layer adjacent to the polarizer is absorbed. It is considered that this is due to the penetration into the polarizer in the thickness direction from this layer.

In a general polarizing film, since both main surfaces of the polarizer are covered with a protective film, the amount of water that penetrates into the polarizer through the protective film is relatively small. Further, the protective film is directly adhered to the main surface of the polarizer or is adhered via an adhesive layer. The adhesive layer is a layer of cured product of the adhesive. Therefore, the high adhesiveness at the interface between the polarizer and the protective film or the adhesive layer suppresses the intrusion of moisture from this interface. In addition, the invasion of moisture through the adhesive layer, which is a cured product, is also suppressed. Therefore, in a general polarizing film in which both main surfaces of the polarizer are covered with a protective film, discoloration at the end of the polarizer is hardly a problem.

On the other hand, in a polarizing film, an adhesive layer may be arranged adjacent to the polarizer. The adhesive layer is a layer composed of a non-curable adhesive and has fluidity. Since the adhesive layer does not require a curing step, it has the advantages that it can be easily laminated with other members and can be reworked. Further, in the polarizing film used for the flexible image display device, if the adhesive layer is provided, the stress when the flexible image display device is repeatedly bent by the adhesive layer can be relaxed. In such an adhesive layer, the constituent material itself often has a functional group involved in adhesiveness, and since it is more hydrophilic than the cured product constituting the adhesive layer, it is inside the layer as compared with the adhesive layer. Moisture easily invades. Due to the fluidity of the adhesive layer in addition to the hydrophilicity of the material itself, moisture easily penetrates into the inside through the interface between the polarizer and the adhesive layer. Therefore, it has been clarified that in the protectionless polarizing film provided with the adhesive layer, the problem of decolorization at the end portion of the polarizer becomes apparent, especially when exposed to a high temperature and high humidity environment. Further, in recent years, the display range of an image has been widened (for example, full-screen display), and even a slight decolorization of the end portion of the polarizer tends to cause a problem.

In view of the above, the polarizing film on the first side surface of the present invention is formed on the polarizing element, the first decorative layer and the first adhesive layer adhered to one main surface of the polarizer, and the other main surface of the polarizer. A second decorative layer and a second adhesive layer, or a protective film, which are adhered to each other, are provided. The first decorative layer is directly adhered to the peripheral edge of one main surface of the polarizer without an adhesive layer. The first adhesive layer is formed so as to cover a surface of the first decorative layer opposite to the polarizer and a region of one main surface of the polarizer to which the first decorative layer is not adhered. The second decorative layer is directly adhered to the peripheral edge of the other main surface of the polarizer without an adhesive layer. The second adhesive layer is formed so as to cover a surface of the second decorative layer opposite to the polarizer and a region on the other main surface where the second decorative layer is not adhered. The protective film is directly adhered to the other main surface of the polarizer without an adhesive layer, or is adhered through an adhesive layer. First decorative layer, a second decorative layer, and each of the protective film, the moisture permeability when the thickness of 25μm is not more than 1500g ^/ m 2 · 24h.

With such a configuration, although the polarizing film of the present invention is a protection-less polarizing film, it is possible to reduce decolorization of the polarizer when the polarizing film is exposed to a high temperature and high humidity environment. This is considered to be due to the following reasons.

First, by arranging the decorative layer in a state of being directly adhered to the peripheral edge of the main surface of the polarizer, moisture invades the inside through the interface between the decorative layer and the polarizer in a high temperature and high humidity environment. Is suppressed. Further, since the moisture permeability of the decorative layer arranged on the peripheral edge of the main surface of the polarizer is low, the intrusion of moisture from the end surface of the decorative layer into the inside of the decorative layer is reduced. Therefore, although the adhesive layer, which tends to have high moisture permeability, is arranged adjacent to the polarizer, the invasion of moisture into the polarizer through the adhesive layer is reduced. Further, when the protective film having low moisture permeability is directly adhered to the other main surface of the polarizer without the adhesive layer, or when the protective film is adhered via the adhesive layer, the protector and the protective film or the adhesive layer are adhered. Invasion of moisture into the inside through the interface between the adhesive layer, the adhesive layer, the adhesive layer, and the protective film is suppressed. As described above, it is considered that the decolorization of the polarizer due to the action of moisture is reduced by reducing the invasion of moisture into the polarizer.

In the image display device, there is a lead wire for a drive element or a touch sensor on the outer periphery of the display unit on which the image is displayed. Therefore, the optical laminate used in the image display device or the image display device is generally provided with a decorative layer so that the lead-out wiring cannot be seen from the outside. As described above, since the decorative layer is originally a member arranged in the image display device or the optical laminate, it is not necessary to newly use another member in order to reduce the decolorization of the polarizer, and the protective-less polarized light is used. The original purpose of thinning and cost reduction using a film is not impaired.

Moisture permeability can be measured in accordance with JIS Z 0208: 1976 "Humidity Permeability Test Method for Moisture-Proof Packaging Materials (Cup Method)". The test is performed under temperature and humidity conditions of a temperature of 40 ± 0.5 ° C. and a relative humidity of 90% ± 2%. The value of moisture permeability is inversely proportional to the thickness of the sample to be measured. Therefore, the moisture permeability when the thickness is 25 μm is obtained by multiplying the measured moisture permeability value by the sample thickness (μm) and dividing by 25 μm. Incidentally, the decorative layer is usually because it is very thin layer, the moisture permeability J _t of the laminate of the decorative layer and the substrate was measured, and the moisture permeability J _sub of the moisture permeability J _t and substrate From the following formula, the moisture permeability J of the decorative layer is obtained. Then, the moisture permeability J of the decorative layer is converted into the moisture permeability when the thickness is 25 μm in the same manner as described above.
1 / J _t = 1 / J + 1 / J _sub

Moisture permeability J _t of the laminate base material of the laminate inside the measuring cup, the decorative layer is measured in a state arranged to face the outside. As the base material, a triacetyl cellulose film having a thickness of 25 μm is used. In the laminate, a coating agent containing a component of the decorative layer is applied to one main surface of the base material by a vapor phase method, or the components are deposited by a vapor phase method to form a decorative layer. Obtained by doing.

When the area of one main surface of the decorative layer is 25 cm ² or more, the moisture permeability of the decorative layer can be obtained from the laminated body as described above. When determining the moisture permeability from the decorative layer in an actual polarizing film, the constituent components of the decorative layer and the content ratio of each component are analyzed, and a laminate of the decorative layer and the base material having the same composition is obtained. It is produced as described above, and the moisture permeability of the decorative layer can be determined from this laminated body. When the area of one main surface of the decorative layer is ^{less than 25 cm 2} , the components of the decorative layer and the content ratio of each component are analyzed from the decorative layer in the actual polarizing film, and the moisture permeability is known. The moisture permeability can be estimated in comparison with the decorative layer of. Analysis of the constituents of the decorative layer and their content is performed using, for example, at least one selected from the group consisting of nuclear magnetic resonance, mass spectrometry, gas chromatography, and liquid chromatography.

As described above, the polarizing film of the present invention can reduce decolorization of the polarizer when exposed to a high temperature and high humidity environment. For example, a polarizing film does not contain a bleached portion or contains a bleached portion at the end of the polarizer after being held at 60 ° C. ± 1 ° C. and a relative humidity of 90% ± 2% for 175 hours. Even in this case, the decolorized portion is formed in a region where the distance from the end face of the polarizer is less than 100 μm (preferably 80 μm or less). When the polarizing film is arranged on the main surface of the polarizing element on the visual side, the decorative layer is formed in the immediate vicinity of the end surface even if a decolorized portion is formed at the end portion of the polarizer. , The decolorized part can be concealed by the decorative layer.

The shape of the polarizer is usually film-like. Therefore, the polarizer includes a pair of main surfaces that occupy most of the surface area of the polarizer, and end faces that are continuous with each main surface at the peripheral edge of each main surface. The pair of main surfaces corresponds to the one main surface and the other main surface located on the opposite side of the one main surface. The end portion of the polarizer shall mean the end face of the polarizer and a portion in the vicinity thereof.

The present invention also includes an optical laminate including the above-mentioned polarizing film, an image display device including the optical laminate, and an image display device including the above-mentioned polarizing film. The polarizing film includes a pair of main surfaces that occupy most of the surface of the polarizing film. The main surface on the visible side of the polarizing film is referred to as a first main surface, and the main surface on the side opposite to the first main surface is referred to as a second main surface.

The optical laminate includes the above-mentioned polarizing film and at least one of a window member and a retardation film. The window member is arranged on the first main surface side of the polarizing film, and the retardation film is arranged on the second main surface side of the polarizing film.

The display device includes the above-mentioned polarizing film or the above-mentioned optical laminate, and a panel member. The panel member is arranged on the second main surface side with respect to the polarizing film. The panel member is arranged on the side opposite to the visual viewing side with respect to the optical laminate.

In the present specification, each layer and each member in the stacking direction (in other words, the average thickness direction of each layer or each member) of each layer constituting the polarizing film, the optical laminate, or each member constituting the image display device. The relative positional relationship of the members (or the layers constituting each member) may be expressed by using the expression "viewing side" or "opposite side to the viewing side" of the polarizing film, the image display device, or the optical laminate. be.

In the present specification, the thickness of the member or layer constituting the polarizing film, the optical laminate, or the image display device is the thickness of the polarizing film, the optical laminate, or the image display device, except for the case where the thickness is 25 μm according to the regulation of moisture permeability. A cross section is cut out and is meant to mean the average thickness measured based on a scanning electron microscope (SEM) image of the cross section. The average thickness is obtained by measuring the thickness at an arbitrary plurality of points (for example, 5 points) and averaging the thickness in the image of the cross section.

The configurations of the polarizing film, the optical laminate, and the image display device will be described in more detail below.

(Polarizing film)
The polarizing film includes (i) a polarizer, a first decorative layer and a first adhesive layer bonded to one main surface of the polarizer, and a second decoration bonded to the other main surface of the polarizer. When it has a layer and a second adhesive layer, (ii) a polarizer, a first decorative layer and a first adhesive layer adhered to one main surface of the polarizer, and the other main surface of the polarizer. The case including the case where the adhesive protective film is provided is included. The polarizing film may further include a first separator arranged on the side opposite to the polarizer of the first adhesive layer. When the polarizing film includes a second adhesive layer, the polarizing film may further include a second separator arranged on the opposite side of the polarizing element of the second adhesive layer. When each separator is peeled off and each adhesive layer is attached to another member, the polarizing film can be laminated on the other member.

(Polarizer)
The polarizer is not particularly limited, and those used in the field of image display devices and the like can be used. Examples of the polarizer include a film in which a dichroic substance is adsorbed on a hydrophilic polymer film and uniaxially stretched, and a polyene-based oriented film. Examples of the hydrophilic polymer constituting the hydrophilic polymer film include polyvinyl alcohol-based resins (including partially formalized polyvinyl alcohol-based resins) and partially saponified ethylene-vinyl acetate copolymers. Examples of the dichroic substance include iodine and a dichroic dye. Examples of the material constituting the polyene-based alignment film include a dehydrated product of a polyvinyl alcohol-based resin and a dehydrochlorinated product of a polyvinyl chloride-based resin.

The thickness of the polarizer may be, for example, 1 μm or more and 30 μm or less, 2 μm or more and 15 μm or less, or 3 μm or more and 10 μm or less.

(1st decorative layer and 2nd decorative layer)
The first decorative layer is directly adhered to the peripheral edge of one main surface of the polarizer without an adhesive layer. The second decorative layer is directly adhered to the peripheral edge of the other main surface of the polarizer without an adhesive layer. As a result, the invasion of moisture into the inside through the adhesive layer is suppressed, and the invasion of moisture into the interior through the interface between the polarizer and the decorative layer is reduced. Therefore, although the adhesive layer, which tends to have high moisture permeability, is arranged adjacent to the polarizer, it is possible to effectively reduce the invasion of water into the polarizer through the adhesive layer.

Each decorative layer is provided on the outer periphery of the display unit on which the image is displayed so that the lead wiring of the drive element or the touch sensor is not visible from the outside. Therefore, each decorative layer may have a shape that can conceal the lead-out wiring and the like, and may be formed on at least a part of the peripheral edge of the main surface of the polarizer. From the viewpoint of further enhancing the effect of suppressing the intrusion of water into the polarizing film, it is preferable to form the entire peripheral edge portion in a frame-like pattern so as to surround the inner region of the main surface. Further, from the viewpoint of enhancing the effect of suppressing decolorization in the polarizer, it is preferable that the end face of the polarizer is flush with the end face of each decorative layer or located inside the end face of each decorative layer. ..

Moisture permeability when the thickness of the decorative layer is 25μm, the long 1500g ^/ m 2 · 24h or less, more preferably at most 1300g ^/ m 2 · 24h or less or 1200g ^/ m 2 · 24h. The lower limit of the moisture permeability when the thickness of the decorative layer is 25μm is not particularly limited, for example, a 500g ^/ m 2 · 24h or more, may be 1000g ^/ m 2 · 24h or more. These upper limit values and lower limit values can be arbitrarily combined.

The thickness of the decorative layer is, for example, 3 μm or more. From the viewpoint of further enhancing the effect of suppressing the invasion of water from the thickness direction of the decorative layer, the thickness of the decorative layer is preferably 5 μm or more, and may be 6 μm or more. The thickness of the decorative layer is, for example, 20 μm or less, and may be 15 μm or less. From the viewpoint that the step due to the decorative layer can be easily eliminated by the adhesive layer, the thickness of the decorative layer is preferably 10 μm or less, and may be 8 μm or less. Further, when the thickness of the decorative layer is in such a range, it is easy to secure high bending resistance of the image display device and the optical laminate. These lower limit values and upper limit values can be arbitrarily combined.

The width of each decorative layer is, for example, 0.1 mm or more. The width of each decorative layer is preferably 0.5 mm or more, preferably 1 mm or more, from the viewpoint of enhancing the effect of suppressing the intrusion of water through the interface between the decorative layer and the polarizer and the decorative layer. You may. The upper limit of the width of each decorative layer may be selected within a range in which the wiring or the like can secure concealment and visibility, but may be, for example, 30 mm or less, or 20 mm or less. These lower limit values and upper limit values can be arbitrarily combined.

The width of the decorative layer is the width of the decorative layer when viewed from the direction perpendicular to the main surface of the polarizer in the polarizing film at any 30 points, and the width of the decorative layer is 10 from the smallest. Let the average value be the average value. The width of the decorative layer may be determined for the polarizing film taken out by peeling another member from the optical laminate or the image display device.

In addition to not reflecting the light from the viewing side, the decorative layer is required to shield the light from the side opposite to the viewing side. Examples of the decorative layer include an ink layer, a metal thin film, and a metal fine particle-containing layer (thin film). The decorative layer may have a single-layer structure or a laminated structure. The decorative layer having a laminated structure may be, for example, a laminated body having at least two layers selected from the group consisting of an ink layer, a metal thin film, and a metal fine particle-containing layer. Such a laminate includes not only a laminate having at least two types of layers selected from the group consisting of an ink layer, a metal thin film, and a metal fine particle-containing layer, but also a laminate of two or more ink layers having different compositions. , A laminate of two or more metal thin films having different compositions, a laminate of two or more layers containing metal fine particles having different compositions, and the like are also included. The metal fine particle-containing layer contains, for example, metal fine particles and a binder resin. In the laminated body, it is desirable that the adjacent layers or thin films are directly adhered to each other without an adhesive layer intervening.

Among the decorative layers, for the ink layer or the metal fine particle-containing layer, for example, a coating agent (including ink) containing the constituent components of the decorative layer is applied to the main surface of the polarizer to solidify the coating film of the coating agent. It is formed by doing. The solidification of the coating film can be carried out by at least one selected from drying, heating, exposure and the like. The coating agent includes, for example, fine particles exhibiting concealing properties, a resin binder, and if necessary, a liquid medium. The coating agent may contain additives, if necessary.

Examples of the fine particles exhibiting the hiding property include pigments and inorganic fine particles. Examples of the pigment include an inorganic pigment (carbon black and the like), a dispersed organic pigment, and a soluble fluorescent pigment. Examples of the inorganic fine particles include fine particles of inorganic components other than pigments. Examples of the inorganic component include metals, alloys, metal compounds (oxides, nitrides, etc.), carbonaceous materials (graphitized carbon, etc.) and the like. As the fine particles exhibiting the hiding property, one type may be used alone, or two or more types may be used in combination.

Examples of the resin binder include thermoplastic resins and curable resins (thermosetting resins, photocurable resins, etc.). Thermoplastic resins, particularly cyclic olefin resins and acrylic resins, are preferable from the viewpoint that lower moisture permeability can be easily obtained and high dispersion stability in the coating agent can be easily ensured. One type of resin binder may be used alone, or two or more types may be used in combination.

As the liquid medium, for example, an organic liquid medium, water, and a mixture thereof are used depending on the components of the coating agent. As the liquid medium, it is preferable to use an organic liquid medium (ethanol, isopropanol, glycol ether, etc.). As the liquid medium, one type may be used alone, or two or more types may be used in combination.

Known additives can be used, and examples thereof include dispersants, surfactants, and coupling agents. However, the additives are not limited to these.

The decorative layer may be formed by the vapor phase method. More specifically, among the decorative layers, the metal thin film may be formed, for example, by depositing the constituent components on the main surface of the polarizer by the vapor phase method. Examples of the gas phase method include a sputtering method, a vacuum deposition method, a chemical vapor deposition (CVD) method, and an electron beam deposition method.

(1st adhesive layer and 2nd adhesive layer)
The first adhesive layer is formed so as to cover a surface of the first decorative layer opposite to the polarizer and a region of one main surface of the polarizer to which the first decorative layer is not adhered. The second adhesive layer is formed so as to cover a surface of the second decorative layer opposite to the polarizer and a region of the other main surface of the polarizer to which the second decorative layer is not adhered.

The storage elastic modulus of each adhesive layer at 25 ° C. is usually 10 MPa or less, may be 3 MPa or less, or may be 1 MPa or less. When the storage elastic modulus of the adhesive layer is in such a range, high adhesiveness can be ensured, and unlike the case of a hardened adhesive layer, the stress due to pressing can be easily relieved. The storage elastic modulus of each adhesive layer at 25 ° C. may be 0.001 MPa or more, or 0.005 MPa or more. These upper limit values and lower limit values can be arbitrarily combined.

On the other hand, the storage elastic modulus of the adhesive layer at 25 ° C. is larger than 10 MPa, may be 100 MPa or more, and is usually about 1 GPa. In the present specification, the adhesive layer means a layer having such a storage elastic modulus.
In this way, the adhesive layer is distinguished from the adhesive layer by the storage elastic modulus.

The storage elastic modulus of the adhesive layer can be measured according to JIS K 7244-1: 1998. Specifically, first, a molded product having a thickness of about 1.5 mm is produced by using the pressure-sensitive adhesive layer or the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer. This molded product is punched into a disk shape having a diameter of 7.9 mm to prepare a test piece. This test piece is sandwiched between parallel plates, and the viscoelasticity is measured under the following conditions using a dynamic viscoelasticity measuring device (for example, "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific), and the viscoelasticity is measured at 25 ° C. The storage elastic modulus in. The storage elastic modulus of the adhesive layer is also obtained in the same manner as in the case of the adhesive layer.

(Measurement condition)
Deformation mode: Torsion measurement frequency: 1Hz
Measurement temperature: -40 ° C to + 150 ° C
Temperature rise temperature: 5 ° C / min

From the viewpoint of ensuring high visibility of the panel member when used in an image display device, the total light transmittance of each adhesive layer is preferably 85% or more, more preferably 90% or more.

The total light transmittance of the adhesive layer can be measured according to JIS K 7136K: 2000. The measurement was carried out by arranging an adhesive layer or an adhesive constituting the adhesive layer on non-alkali glass (thickness 0.8 to 1.0 mm, total light transmittance 92%) until the thickness became about 1.5 mm. Pieces are used.

Each pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive. The type of adhesive is not particularly limited, and for example, acrylic adhesive, rubber adhesive, silicone adhesive, urethane adhesive, vinyl alkyl ether adhesive, polyvinylpyrrolidone adhesive, polyacrylamide adhesive. , And a cellulose-based pressure-sensitive adhesive. Adhesives include, for example, base polymers, cross-linking agents, additives (eg, tackifiers, coupling agents, polymerization inhibitors, cross-linking retarders, catalysts, plastics, softeners, fillers, colorants, metal powders. , Ultraviolet absorbers, light stabilizers, antioxidants, deterioration inhibitors, surfactants, antistatic agents, surface lubricants, leveling materials, corrosion inhibitors, particles of inorganic or organic materials (metal compound particles (metal oxidation) (Partial particles, etc.), resin particles, etc.) can be included, but the present invention is not limited to these.

The pressure-sensitive adhesives constituting the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be the same or different.

The thickness of each adhesive layer may be 50 μm or less, 40 μm or less, or 30 μm or less. From the viewpoint of easily ensuring high flexibility of the image display device or the optical laminate, the thickness of each adhesive layer is preferably 5 μm or more, and may be 7 μm or more. From the viewpoint of easily absorbing the step of the decorative layer, the thickness of each adhesive layer is preferably 10 μm or more.

From the viewpoint of easily absorbing the step due to the decorative layer, the thickness of each adhesive layer may be 1.5 times or more, 2.5 times or more, or 3 times or more the thickness of the decorative layer to be adhered.

In each adhesive layer, for example, in a state where the decorative layer is adhered to the peripheral edge of the main surface of the polarizer, the surface of the decorative layer opposite to the polarizer and the decorative layer of the polarizer are not adhered. It can be formed by applying a pressure-sensitive adhesive constituting each pressure-sensitive adhesive layer so as to cover the region, or by transferring a pressure-sensitive adhesive molded into a sheet shape. When transferring the pressure-sensitive adhesive, the pressure-sensitive adhesive formed into a sheet on the surface of the first separator or the second separator may be transferred together with the separator.

(1st separator and 2nd separator)
As each separator, for example, a release sheet including a base sheet and a release agent arranged on at least one main surface of the base sheet is used. Each separator is arranged with the release agent in contact with the first adhesive layer or the second adhesive layer (more specifically, the surface of each adhesive layer opposite to the polarizer).

The base sheet may be any as long as it has appropriate strength and flexibility and a layer of a release agent can be easily formed. As the base sheet, a resin film, paper, a laminate thereof, or the like is used. The material of the base sheet is determined according to the type of release agent, other configurations of the polarizing film, and the like. As the resin film, for example, a polyester film (polyethylene terephthalate film or the like) or a polyolefin film (polypropylene film or the like) may be used. The thickness of the base sheet is not particularly limited, and can be selected in consideration of desired peelability. As the release agent, a known one can be used, and it is preferable to select one having a small amount of the adhesive layer remaining on the separator. For example, a silicone-based release agent or a fluorine-based release agent may be used.

(Protective film)
The protective film is directly adhered to the other main surface of the polarizer without an adhesive layer, or is adhered through an adhesive layer. The protective film is arranged so as to cover the entire other main surface of the polarizer.

Moisture permeability when the thickness of the protective film is 25μm may be any 1500g ^/ m 2 · 24h or less, preferably not more than ^{1000g / m 2 · 24h, 700g} / m 2 · 24h or less or 500g ^/ m 2 · 24h or less Is more preferable. The lower limit of the moisture permeability when the thickness of the protective film of 25μm is not particularly limited, for example, at 50g ^/ m 2 · 24h or more, may be 100g ^/ m 2 · 24h or more. These upper limit values and lower limit values can be arbitrarily combined.

As the protective film, a polymer film that exhibits low moisture permeability as described above and is excellent in transparency, mechanical strength, thermal stability, moisture barrier property, and optical isotropic property is used, for example. As the polymer material having such properties, the protective film preferably contains at least one selected from the group consisting of an acrylic resin and a cyclic polyolefin resin. The protective film containing these resins has low moisture permeability and can further enhance the effect of reducing decolorization of the polarizer.

Examples of the acrylic resin include homopolymers or copolymers containing at least one monomer unit selected from the group consisting of alkyl acrylates and alkyl methacrylates. The number of carbon atoms in the alkyl moiety of the alkyl acrylate and the alkyl methacrylate is preferably 1 to 4, and may be 1 or 2. From the viewpoint of excellent transparency, heat resistance, and moisture resistance, it is preferable to use an acrylic resin containing at least methyl methacrylate units (that is, a methacrylic resin) as the acrylic resin.

The acrylic resin may have a ring structure in the main chain. As such a ring structure, an imide ring structure is preferable from the viewpoint of excellent heat resistance and moisture resistance. Examples of the imide ring structure include a glutarimide structure, an N-substituted maleimide structure (for example, a cyclohexylmaleimide structure, a methylmaleimide structure, a phenylmaleimide structure, and a benzylmaleimide structure). The acrylic resin preferably contains a methacrylic resin having an imide ring structure in the main chain.

Examples of the cyclic polyolefin resin include homopolymers and copolymers using cyclic olefins such as norbornene and dicyclopentadiene as monomers. Cyclic olefins also include those having a substituent (eg, 1-methylnorbornene, 4-methylnorbornene, 4-phenylnorbornene). The cyclic polyolefin resin using norbornene may be obtained by ring-opening polymerization of norbornene, or may be obtained by addition polymerization.

The protective film may contain other resins in addition to the above resins. Other resins are not particularly limited, but are, for example, cellulose-based resins, polyolefin-based resins other than cyclic polyolefins, imide-based resins (including phenylmaleimide-based resins), polyamide-based resins, polycarbonate-based resins, and polyester-based resins (poly). Allylate resin (including polyethylene terephthalate resin), acetate resin, sulfone resin (including polyether sulfone resin), polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol type Examples thereof include resins, sulfide resins (for example, polyphenylene sulfide resins), polyether ether ketone resins, epoxy resins, and urethane resins. The ratio of other resins is adjusted so that the moisture permeability of the protective film is within the above range.

The thickness of the protective film is, for example, 20 μm or more. From the viewpoint of reducing the moisture permeability of the entire protective film and further enhancing the effect of suppressing the invasion of moisture from the thickness direction, the thickness of the protective film is preferably 35 μm or more, more preferably 40 μm or more. The upper limit of the thickness of the protective film is not particularly limited, but may be 100 μm or less, or 60 μm or less. These lower limit values and upper limit values can be arbitrarily combined.

(Adhesive layer)
The adhesive layer is a layer of cured product of the adhesive. As the adhesive, a curable adhesive used for a polarizing film can be used. Examples of such an adhesive include an active energy ray-curable adhesive (ultraviolet curable adhesive, electron beam curable adhesive, etc.) and a thermosetting adhesive. Examples of such an adhesive include, but are not limited to, an acrylic adhesive, an epoxy adhesive, and a urethane adhesive.

The storage elastic modulus of the adhesive layer at 25 ° C. is in the above range.

The thickness of the adhesive layer is, for example, 5 μm or less. From the viewpoint of further reducing the invasion of water through the adhesive layer, the thickness of the adhesive layer is preferably 3 μm or less, more preferably 2 μm or less or 1.5 μm or less. From the viewpoint of further reducing the intrusion of water through the interface between the polarizer and the protective film, the thickness of the adhesive layer is preferably 0.5 μm or more, more preferably 0.8 μm or more or 1 μm or more. These upper limit values and lower limit values can be arbitrarily combined.

In the polarizing film, for example, a polarizing element is directly laminated on one main surface of the protective film without an adhesive layer, or a polarizing element is laminated via an adhesive layer, and the main surface on the opposite side of the protective film of the polarizing element is laminated. The first decorative layer is formed, and the separately formed first adhesive layer (and, if necessary, the first separator) is attached to the region where the first decorative layer and the first decorative layer of the polarizer are not adhered. It can be formed by transferring so as to cover. Further, in the polarizing film, for example, a first decorative layer is formed on one main surface of the polarizer in the same manner as described above, a first adhesive layer (and a first separator if necessary) is transferred, and the polarizing film is transferred. A protective film may be formed on the other main surface of the polarizer by directly laminating or laminating through an adhesive layer without interposing an adhesive layer. In the polarizing film, for example, a first decorative layer is formed on one main surface of the polarizer in the same manner as described above, a first adhesive layer (and a first separator if necessary) is transferred, and a first. As in the case of the decorative layer, a second decorative layer is formed on the other main surface of the polarizer, and as in the case of the first adhesive layer (and the first separator), the second adhesive layer (and if necessary) It may be formed by transferring the second separator) accordingly.

(Optical laminate and image display device)
The optical laminate may include the above-mentioned polarizing film and at least one of a window member and a retardation film. The image display device includes the above-mentioned polarizing film or optical laminate and a panel member. The optical laminate or the image display device may further include a touch sensor. Alternatively, a panel member with a touch sensor may be used as the panel member. The optical laminate or image display device may include an adhesive layer or an adhesive layer that adheres between adjacent members (or layers). When the polarizing film includes at least one of the first separator and the second separator, the image display device includes the polarizing film with the first separator and the second separator peeled off. The optical laminate may include a polarizing film in which the polarizing film has at least one of the first separator and the second separator peeled off.

In the optical laminate or the image display device, the window member is arranged on the first main surface side on the viewing side of the polarizing film, and the retardation film is arranged on the second main surface side opposite to the viewing side of the polarizing film. Will be done. The panel member is arranged on the second main surface side of the polarizing film. When the first main surface of the polarizing film is on one main surface side of the polarizing element, the second main surface is on the other main surface side of the polarizing element. When the first main surface of the polarizing film is the other main surface side of the polarizing element, the second main surface is one main surface side of the polarizing element. When the polarizing film contains a protective film, the protective film may be located on either the first main surface side or the second main surface side, but from the viewpoint of protecting the surface on the viewing side, the protective film is used. 1 It is more advantageous to position it on the main surface side.

(Window member)
The window member is arranged on the outermost surface of the image display device or the optical laminate on the visible side in order to prevent damage to the optical laminate such as a polarizing film or other members constituting the image display device.

The window member usually comprises at least one layer selected from the group consisting of window film and window glass. The optical laminate or image display device is required to have high transparency (high total light transmittance and low haze, etc.) and high hardness. Further, the flexible image display device is required to have higher flexibility (high commutativity, etc.) in addition to these physical properties. The material of the window film or the window glass is not particularly limited as long as it satisfies these physical characteristics.

Examples of the window glass include a thin glass substrate.

The thickness of the window glass is, for example, 5 μm or more and 40 μm or less, and may be 10 μm or more and 35 μm or less.

Examples of the window film include a transparent resin film. Examples of the resin constituting the transparent resin film include acrylic resin, cyclic polyolefin resin, and other resins (for example, imide resin, polyethylene terephthalate resin, and other polyester resins) exemplified as the material of the protective film contained in the polarizing film. ) At least one selected from the group consisting of. However, the resin constituting the transparent resin film is not limited to these.

The thickness of the window film is, for example, 20 μm or more and 500 μm or less, and may be 30 μm or more and 200 μm or less.

In the present specification, with respect to the polarizing film, the optical laminate, the member (molded body) constituting the image display device, or the material thereof, the transparent material means that the test piece has a total light transmittance of 80% or more. means. A test piece having a thickness of about 1.5 mm and made of a transparent material or member is used for measuring the total light transmittance. The total light transmittance can be measured according to the case of the adhesive layer.

The window member may include a hard coat layer. The hard coat layer is usually laminated with the window film. From the viewpoint that a high damage prevention effect of the window film can be easily obtained, it is preferable that the hard coat layer is provided at least on the surface of the window film on the visible side.

The thickness of the hard coat layer is, for example, 1 μm or more and 100 μm or less, and may be 1 μm or more and 50 μm or less. When the window member includes a plurality of hard coat layers, the thickness of each hard coat layer may be within such a range.

The hard coat layer is formed by, for example, applying a curable coating agent to the surface of a underlying layer (for example, a window film) and curing it.

As the coating agent, for example, those used for optical films can be used. Examples of the coating agent include, but are not limited to, an acrylic coating agent, a melamine coating agent, a urethane coating agent, an epoxy coating agent, a silicone coating agent, and an inorganic coating agent.

The coating agent may contain additives. Additives include, for example, silane coupling agents, colorants, dyes, powders or particles (pigments, inorganic or organic fillers, particles of inorganic or organic materials, etc.), surfactants, plasticizers, antistatic agents. Examples thereof include, but are not limited to, agents, surface lubricants, leveling agents, antioxidants, light stabilizers, ultraviolet absorbers, polymerization inhibitors, antifouling materials, and the like.

The window member may include another layer (hereinafter, referred to as layer A), if necessary. Examples of the layer A include an antireflection layer, an antiglare layer, an antifouling layer, a sticking prevention layer, a hue adjustment layer, an antistatic layer, an easy-adhesion layer, a precipitation prevention layer such as ions or oligomers, a shock absorption layer, and a shatterproof layer. Can be mentioned. The window member may include one layer A or a plurality of layers. The layer A is, for example, a visible side of one layer (for example, a window film or a window glass) or a laminate of two or more layers (for example, a laminate of a window film and a hard coat layer) constituting a window member. It is provided on the surface side or the surface opposite to the visual recognition side. The layer A may be formed directly on the layer constituting the window member by a coating or the like, or may be laminated via an adhesive layer or an adhesive layer.

The thickness of the window member is, for example, 0.02 mm or more and 0.6 mm or less, and may be 0.03 mm or more and 0.3 mm or less.

(Phase difference film)
Examples of the retardation film include a retardation film used in an optical laminate or an image display device. Examples of the retardation film include a uniaxial or biaxial retardation film, a liquid crystal film having a liquid crystal twist orientation or a liquid crystal tilt orientation, a 1/2 wave plate, a 1/4 wave plate, and the like. The optical laminate may include a single-layer retardation film, or may include a laminate of two or more layers of retardation films.

The thickness of the retardation film may be, for example, 10 μm or more and 100 μm or less, and may be 15 μm or more and 60 μm or less.

The retardation film may be laminated directly on the protective film by using a coating or the like, or may be laminated via an adhesive layer. Further, the retardation film may be attached to the first adhesive layer or the second adhesive layer.

A laminate including a polarizing film and a retardation film is generally referred to as an optical film. If necessary, the optical film may further include a layer (layer B) other than the polarizing film and the retardation film.

(Layer B)
Examples of the layer B include an optically anisotropic film other than the polarizer and the retardation film, and a base material layer (or protective layer).

Examples of the optically anisotropic film other than the polarizer and the retardation film include a viewing angle expanding film, a viewing angle limiting (peep spinning) film, a brightness improving film, and an optical compensation film. It is not limited. The optical laminate or the image display device may contain one layer of these optically anisotropic films, or may contain two or more layers.

The other optically anisotropic film may be directly laminated on the adjacent layer (for example, a retardation film) by using a coating or the like, or may be laminated on the adjacent layer via an adhesive layer or an adhesive layer. May be good.

As the base material layer, a thin glass substrate, a polymer film, or the like is used. Examples of the polymer material constituting the polymer film include at least one selected from the group consisting of the acrylic resin, the cyclic polyolefin resin, and other resins exemplified as the material of the protective film contained in the polarizing film. From the viewpoint of thinning, the optical film preferably does not have such a base material layer.

The thickness of the layer B is not particularly limited, and is, for example, 0.1 μm or more and 100 μm or less.

(Touch sensor)
As the touch sensor, for example, a touch sensor used in the field of an image display device or the like is used. Examples of the touch sensor include, but are not limited to, a resistive film type, a capacitance type, an optical type, and an ultrasonic type. High sensitivity can be easily obtained by using a capacitive touch sensor.

Capacitive touch sensors usually include a transparent conductive layer. Examples of such a touch sensor include a laminate of a transparent conductive layer and a transparent base material. Examples of the transparent base material include a transparent film.

The transparent conductive layer is not particularly limited, but a conductive metal oxide, metal nanowires, or the like is used. Examples of the metal oxide include indium oxide (ITO: Indium Tin Oxide) containing tin oxide and tin oxide containing antimony. The transparent conductive layer may be a conductive pattern composed of a metal oxide or a metal. Examples of the shape of the conductive pattern include, but are not limited to, a striped shape, a square shape, and a grid shape.

The surface resistance value of the transparent conductive layer may be, for example, 0.1 Ω / □ or more and 1000 Ω / □ or less, and may be 0.5 Ω / □ or more and 500 Ω / □ or less.

The thickness of the transparent conductive layer is, for example, 0.005 μm or more and 10 μm or less, and may be 0.01 μm or more and 3 μm or less.

As the transparent film, for example, a transparent resin film is used. Examples of the resin constituting the transparent resin film include at least one selected from the group consisting of the acrylic resin, the cyclic polyolefin resin, and other resins exemplified as the material of the protective film contained in the polarizing film. Of these, polyester resins, polyimide resins and polyether sulfone resins are preferable. However, the resin constituting the transparent resin film is not limited to these resins.

From the viewpoint of enhancing the adhesion between the transparent conductive layer and the transparent base material, a surface-treated transparent base material may be used. As the surface treatment, a known one can be adopted. Further, if necessary, the transparent base material may be subjected to, for example, a dust removal or cleaning treatment (cleaning treatment using a solvent, ultrasonic waves, or the like) prior to laminating the transparent conductive layer.

If necessary, the touch sensor may include a transparent conductive layer and a layer other than the transparent base material (hereinafter, referred to as layer C). For example, an undercoat layer or an oligomer precipitation prevention layer may be provided as the layer C between the transparent conductive layer and the transparent base material. Further, the layer C may be laminated on at least one surface of the transparent conductive layer and the transparent base material. However, layer C is not limited to these layers. The layer C may be laminated on the transparent conductive layer or the transparent base material via the adhesive layer or the adhesive layer, if necessary.

The thickness of the entire touch sensor is, for example, 0.005 mm or more and 0.25 mm or less, and may be 0.01 mm or more and 0.2 mm or less.

(Adhesive layer and separator)
The optical laminate may include an adhesive layer for attaching and laminating to other members constituting the image display device such as a panel member. The optical laminate may further include a separator (third separator) that covers such an adhesive layer. For the configuration of the adhesive layer, the description of the first adhesive layer and the second adhesive layer can be referred to. For the configuration of the third separator, the description of the first separator and the second separator can be referred to. Depending on the layer structure of the optical laminate, the adhesive layer may be arranged on one of the main surface side of the optical laminate on the visible side and the main surface side of the optical laminate on the opposite side to the visible side, and may be arranged on both main surface sides. It may have been. The optical laminate provided with the third separator is used in an image display device with the third separator peeled off.

When the optical laminate contains a polarizing film in a state of including at least one of a first separator and a second separator, it is used in an image display device in a state where each separator is peeled off.

(Panel member)
The panel member included in the image display device includes, for example, at least an image display panel. A sealing member (thin film sealing layer or the like) may be arranged on the visual side of the image display panel. The sealing member is usually arranged directly on the main surface of the image display panel on the visual side.

As the image display panel, a known one is used. Examples of the image display panel include an organic electroluminescence (EL) panel.

(Protective member)
The image display device may include a laminate of a panel member and a protective member. Examples of the protective member include a sheet or film (or substrate) that holds or protects the panel member. The protective member may be one that holds the panel member, has an appropriate strength for protecting the panel member, and has an appropriate flexibility that does not hinder the flexibility of the flexible image display device. As the protective member, a resin sheet or the like is used. The material of the resin sheet is not particularly limited and can be appropriately selected depending on the type of the image display panel, for example.

(Panel member with touch sensor)
The image display device may include a panel member with a touch sensor. The panel member with a touch sensor is one in which the touch sensor and the panel member are integrated. When the image display device includes a panel member with a touch sensor, the other touch sensor as described above is unnecessary.

Such a panel member with a touch sensor includes, for example, a structure in which an antistatic capacity type touch sensor of a metal mesh electrode is formed on a thin film sealing layer of an organic light emitting diode (OLED). NS. As the touch sensor, the above description may be referred to. However, the panel member with the touch sensor does not include the adhesive layer.

For the panel members constituting the panel member with the touch sensor, the above description of the panel member can be referred to.

The panel member with a touch sensor may include a protective member. As the protective member, the above description can be referred to.

The thickness of the entire panel member with a touch sensor is, for example, 0.005 mm or more and 0.1 mm or less, and may be 0.01 mm or more and 0.05 mm or less.

(others)
The optical laminate or the image display device may include a decorative layer (third decorative layer) other than the first decorative layer and the second decorative layer, if necessary. The optical laminate or the image display device may include one third decorative layer, or may include two or more third decorative layers. The third decorative layer is arranged, for example, on the visual side of the touch sensor or the panel member with the touch sensor in contact with the adhesive layer. The third decorative layer may be contained in a member other than the polarizing film. The third decorative layer may be included in the polarizing film, but is not adhered to the polarizer.

The third decorative layer may be an ink layer, a metal thin film, a metal fine particle-containing layer, a laminate, or the like as described for the first decorative layer and the second decorative layer.

The thickness of the third decorative layer is, for example, 20 μm or less, and may be 15 μm or less. From the viewpoint of ensuring a higher concealing effect of the lead wiring, the thickness of the third decorative layer may be 10 nm or more, 30 nm or more, or 50 nm or more. These upper limit values and lower limit values can be arbitrarily combined.

When the third decorative layer is formed by using the coating agent, the primer layer may be arranged on the surface of the member or layer (excluding the adhesive layer) to which the coating agent is applied prior to the application. The primer layer contains, for example, at least one selected from the group consisting of metal compounds (metal oxides, metal nitrides, metal carbides, metal sulfides, etc.) and resin materials. The primer layer is preferably transparent.

The thickness of the primer layer is, for example, 500 nm or less, and may be 100 nm or less or 30 nm or less.

The optical laminate and the image display device can be formed by, for example, laminating the constituent members, respectively. The stacking order is not particularly limited and may be determined in consideration of workability and the like. Lamination may be performed while arranging an adhesive layer or an adhesive layer between the members (or layers) to be laminated.

FIG. 1 is a schematic cross-sectional view of a flexible image display device according to an embodiment of the present invention. The flexible image display device 1 includes a laminated body of a window member 13, an optical film 10 including a polarizing film 11, a touch sensor 14, and a panel member 15. The touch sensor 14 and the panel member 15 constitute a panel member with a touch sensor as described above. The optical film 10 and the window member 13 are laminated with the adhesive layer 22 interposed therebetween. An adhesive layer 23 is interposed between the touch sensor 14 and the optical film 10. In FIG. 1, the laminated body of the configuration excluding the touch sensor 14 and the panel member 15 and the third separator (not shown) corresponds to the optical laminated body.

The window member 13 is adhered to the first main surface of the polarizing film 11 via an adhesive layer 22. The window member 13 includes, for example, a window film 131 and a hard coat layer 132 laminated on the window film 131. The hard coat layer 132 is provided on the side opposite to the optical film 10 side of the window member 13.

The optical film 10 includes a polarizing film 11 and a retardation film 12 adhered to a second main surface of the polarizing film 11. The polarizing film 11 has a polarizing element 111, a first decorative layer 112a and a first adhesive layer 113a bonded to one main surface of the polarizing element 111, and an adhesive layer 115 to the other main surface of the polarizing element 111. A protective film 114 adhered to the surface is provided. The first decorative layer 112a is directly adhered to the peripheral edge of one main surface of the polarizer 111 without an adhesive layer. The first adhesive layer 113a is formed so as to cover the main surface of the first decorative layer 112a opposite to the polarizer 111 and the region where the first decorative layer 112a of the polarizer 111 is not adhered. The main surface of the protective film 114 on the opposite side of the polarizing element 111 corresponds to the first main surface of the polarizing film 11, and the main surface of the first adhesive layer 113a on the opposite side of the polarizing element 111 is the polarizing film 11. Corresponds to the second main surface.

Each of the first decorative layer 112a and the protective film 114, moisture permeability at a thickness of 25μm is not more than 1500g ^/ m 2 · 24h. As described above, in the polarizing film 11, the low moisture permeability first decorative layer 112a is directly adhered to the peripheral edge of one main surface of the polarizer 111 without an adhesive layer, and also protects the low moisture permeability. The film 114 is adhered to the other main surface of the polarizer 111 via an adhesive layer. As a result, the intrusion of moisture from the side surface of the polarizing film 11 into the polarizing film 11 is reduced. Therefore, the decolorization of the polarizer 111 can be reduced.

In FIG. 1, the protective film 114 is arranged on the first main surface side, and the first decorative layer 112a and the first adhesive layer 113a are arranged on the second main surface side, but the protective film 114 is arranged on the second main surface side. The first decorative layer 112a and the first adhesive layer 113a may be arranged on the side and may be arranged on the first main surface side.

FIG. 2 is a schematic cross-sectional view of a flexible image display device according to another embodiment of the present invention. The flexible image display device 101 of FIG. 2 has the same configuration as that of FIG. 1 except that the configuration of the polarizing film 11 is different from that of FIG. 1, and the description of FIG. 1 can be referred to.

The polarizing film 11 of the image display device 101 is the same as the polarizing film 11 of FIG. 1 except that the protective film 114 and the adhesive layer 115 are replaced with the second decorative layer 112b and the second adhesive layer 113b. The second decorative layer 112b is directly adhered to the peripheral edge of the other main surface of the polarizer 111 without an adhesive layer. The second adhesive layer 113b is formed so as to cover the main surface of the second decorative layer 112b opposite to the polarizer 111 and the region where the second decorative layer 112b of the polarizer 111 is not adhered.

Each of the first decorative layer 112a and the second decorative layer 112b, the moisture permeability when the thickness of 25μm is not more than 1500g ^/ m 2 · 24h. As described above, in the polarizing film 11, the low-moisture-permeable first decorative layer 112a and the second decorative layer 112b are directly attached to the peripheral edges of each main surface of the polarizer 111 without an adhesive layer. It is glued. As a result, the intrusion of moisture from the side surface of the polarizing film 11 into the polarizing film 11 is reduced. Therefore, the decolorization of the polarizer 111 can be reduced.

[Example]
Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<< Example 1 >>
(1) Preparation of Evaluation Sample An evaluation sample of a laminate containing the polarizing film 11 as shown in FIG. 3 was prepared by the following procedure.
(A) Preparation of Polarizer 111 An amorphous polyethylene terephthalate film (thickness 100 μm) containing 7 mol% of isophthalic acid unit was prepared as a base material made of a thermoplastic resin, and an output discharge of ^{58 W / m 2 · min was prepared on the surface.} Corona discharge treatment was performed in an amount.

Add 1% by mass of acetoacetyl-modified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Gosefima Z200 (average degree of polymerization 1200, saponification degree 98.5 mol%, acetoacetylation degree 5 mol%)) The polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2%) was prepared, and an aqueous coating liquid containing 5.5% by mass of a polyvinyl alcohol (PVA) -based resin was prepared.

A coating liquid is applied to the surface of the base material so that the film thickness after drying is 12 μm, and the PVA-based resin layer is formed on the base material by drying in an atmosphere of 60 ° C. for 10 minutes by hot air drying. The provided laminate was produced.

The obtained laminate was first stretched 1.8 times at a free end (auxiliary stretching in the air) at 130 ° C. in the air to produce a stretched laminate. Next, a step of insolubilizing the PVA layer in which the PVA molecules contained in the stretched laminate were oriented was performed by immersing the stretched laminate in a boric acid insoluble aqueous solution having a liquid temperature of 30 ° C. for 30 seconds. The boric acid insolubilized aqueous solution in this step is a boric acid aqueous solution having a boric acid content of 3 parts by mass with respect to 100 parts by mass of water. A colored laminate was produced by dyeing the obtained stretched laminate. In the colored laminate, the stretched laminate is mixed with a dyeing solution containing iodine and potassium iodide at a liquid temperature of 30 ° C., so that the single transmittance of the PVA layer constituting the polarizing element finally produced is 40 to 44%. The PVA layer contained in the stretched laminate was stained with iodine by immersing the PVA layer in the stretched laminate for a predetermined time. In this step, the staining solution is an aqueous solution containing iodine and potassium iodide (iodine concentration: 0.1-0.4% by mass, potassium iodide concentration: 0.7 to 2.8% by mass, iodine and potassium iodide). The ratio of the concentrations of: 1: 7). Next, the colored laminate was immersed in a boric acid cross-linked aqueous solution at 30 ° C. for 60 seconds to carry out a step of cross-linking the PVA molecules of the PVA layer on which iodine was adsorbed. The boric acid cross-linked aqueous solution in this step is an aqueous solution containing boric acid and potassium iodide (boric acid content: 3 parts by mass with respect to 100 parts by mass of water, potassium iodide content: 3 parts by mass with respect to 100 parts by mass of water). Department).

The obtained colored laminate is finally stretched 3.05 times in the boric acid aqueous solution at a stretching temperature of 70 ° C. in the same direction as the above stretching in air (stretching in boric acid water). A laminate having a draw ratio of 5.50 times was obtained. The obtained laminate was taken out from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with a potassium iodide aqueous solution (potassium iodide content: 4 parts by mass with respect to 100 parts by mass of water). The washed laminate was dried by a drying step with warm air at 60 ° C. The thickness of the polarizer 111 contained in the dried laminate was 5 μm.

(B) Preparation of Protective Film 114 As the protective film 114, an acrylic film obtained by molding a methacrylic resin pellet having a glutarimide ring unit into a film by extrusion molding and then stretching it was used. The thickness of the protective film 114 was 40 μm. The protective film 114 and the polarizer 111 of the laminate obtained in (a) above are bonded together using an adhesive (active energy ray-curable adhesive), and the adhesive is cured by irradiating with ultraviolet rays under the following conditions. I let you. Next, by removing the base material, a laminate (polarizing film) of the protective film 114 and the polarizer 111 bonded via the adhesive layer 115 was produced.

Gallium-filled metal halide lamp: Fusion UV Systems. Product name "Light HAMMER10" manufactured by Inc.
Bulb: V bulb Peak illuminance: 1600 mW / cm ²
Integrated irradiation dose: ^{1000 mJ / cm 2} (wavelength 380 to 440 nm)

Moisture permeability when the thickness 25μm of the protective film 114 obtained by above procedure was 295g ^/ m 2 · 24h.

The adhesive was prepared by mixing the following components at a ratio such that the content in 100% by mass of the adhesive had the following value, and stirring at 50 ° C. for 1 hour.
Hydroxyethyl acrylamide ... 11.4% by mass
Tripropylene glycol diacrylate ... 57.1% by mass
Acryloyl morpholine ... 11.4% by mass
2-Acetacetoxyethyl methacrylate ... 4.6% by mass
Acrylic polymer (ARUFON UP-1190, manufactured by Toagosei Co., Ltd.) ... 11.4% by mass
2-Methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one ... 2.8% by mass
Diethyl thioxanthone ... 1.3% by mass

(C) Preparation of retardation film 12 (c1) Preparation of first retardation layer Polymerization is carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with a stirring blade and a reflux condenser controlled at 100 ° C. went. In the reactor, bis [9- (2-phenoxycarbonylethyl) fluoren-9-yl] methane (BPFM) 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol). , spiro glycol (SPG) 42.28 parts by weight (0.139 mol), diphenyl carbonate (DPC) 63.77 parts by weight (0.298 mol), and calcium acetate as a catalyst monohydrate 1.19 × ^{10 -2} weight Parts (6.78 × ^10-5 mol) were charged.

After the inside of the reactor was replaced with nitrogen under reduced pressure, the inside of the reactor was heated with a heat medium, and stirring was started when the temperature inside the reactor reached 100 ° C. 40 minutes after the start of the temperature rise, the temperature inside the reactor was brought to 220 ° C. and controlled to maintain this temperature. Decompression was started when the temperature in the reactor reached 220 ° C., and the pressure after 90 minutes was 13.3 kPa.

The phenol vapor produced by the polymerization reaction was guided to a reflux condenser at 100 ° C., the monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the uncondensed phenol vapor was guided to a condenser at 45 ° C. for recovery. Nitrogen was introduced into the first reactor and the pressure was once restored to atmospheric pressure, and then the oligomerized reaction solution in the first reactor was transferred to the second reactor. Then, the temperature rise and depressurization in the second reactor were started, and the temperature in the first reactor was set to 240 ° C. and the pressure was set to 0.2 kPa in 50 minutes. Then, the polymerization was allowed to proceed until the stirring power reached a predetermined value. When the stirring power reached a predetermined value, nitrogen was introduced into the reactor to repressurize, the produced polyester carbonate was extruded into water, and the strands were cut to obtain pellets.

99.5 parts by mass of the obtained polyester carbonate and 0.5 parts by mass of polymethylmethacrylate (PMMA) are melt-kneaded using an extruder to prepare pellets of a resin composition (PMMA content: 0.5% by mass). Obtained. This resin composition (pellet) is vacuum-dried at 80 ° C. for 5 hours, and then a single-screw extruder (manufactured by Isuzu Kakoki Co., Ltd., screw diameter: 25 mm, cylinder set temperature: 220 ° C.), T-die (width: 300 mm). , Set temperature: 220 ° C.), chill roll (set temperature: 120 to 130 ° C.), and a long unstretched film having a length of 3 m, a width of 200 mm, and a thickness of 100 μm using a film forming apparatus equipped with a winder. Made. The obtained long unstretched film was stretched 2.7 times in the width direction (lateral direction) by a fixed-end uniaxial stretching method to prepare a first retardation layer having a thickness of 37 μm.

(C2) Preparation of Laminated Film Containing Second Phase Difference Layer The following chemical formula (I) (numbers 65 and 35 in the formula represent the mass% of the monomer unit and is represented by a block polymer for convenience: weight average molecular weight. 20 parts by mass of the side chain type liquid crystal polymer represented by 5000), 80 parts by mass of a polymerizable liquid crystal (manufactured by BASF: trade name Pariocolor LC242) showing a nematic liquid crystal phase, and a photopolymerization initiator (manufactured by Ciba Speciality Chemicals: trade name Irgacure). 907) A liquid crystal coating solution was prepared by dissolving 5 parts by mass in 200 parts by mass of cyclopentanone.

The obtained liquid crystal coating liquid is applied to a base film (norbornene resin film: manufactured by Nippon Zeon Corporation, trade name "Zeonex") using a bar coater, and then heated and dried at 80 ° C. for 4 minutes. The liquid crystal was oriented by. By irradiating the liquid crystal layer with ultraviolet rays and curing the liquid crystal layer, a liquid crystal solidified layer (thickness: 0.58 μm) to be a second retardation layer was formed on the base film. This layer exhibited a refractive index characteristic of nz> nx = ny. Here, nx is the refractive index in the direction in which the in-plane refractive index of the liquid crystal solidified layer is maximized (that is, the slow-phase axial direction). ny is the refractive index in the plane of the liquid crystal solidified layer in the direction orthogonal to the slow phase axis (that is, the phase advance axis direction). “NZ” is the refractive index in the thickness direction of the liquid crystal solidified layer.

(C3) Preparation of Laminated Body of First Phase Layer and Second Phase Difference Layer A liquid crystal solidified layer (second phase difference layer) of a laminated film is formed on one main surface of the first phase difference layer via an acrylic adhesive. ) Was pasted. Then, the base film contained in the laminated film was removed. In this way, a laminated body in which the first retardation layer and the second retardation layer corresponding to the liquid crystal solidifying layer are laminated was produced.

(D) Preparation of Adhesive An acrylic pressure-sensitive adhesive (acrylic pressure-sensitive adhesive composition) was prepared according to the following procedure.
(D1) Preparation of Acrylic Oligomer 60 parts by mass of dicyclopentanyl methacrylate and 40 parts by mass of methyl methacrylate as monomer components, 3.5 parts by mass of α-thioglycerol as a chain transfer agent, and 100 parts by mass of toluene as a polymerization solvent. Was mixed and stirred at 70 ° C. for 1 hour in a nitrogen atmosphere. Next, 0.2 parts by mass of 2,2'-azobisisobutyronitrile was added as a thermal polymerization initiator, and the mixture was reacted at 70 ° C. for 2 hours, then heated to 80 ° C. and reacted for 2 hours. .. Then, the reaction solution was heated to 130 ° C., and toluene, the chain transfer agent and the unreacted monomer were dried and removed to obtain a solid acrylic oligomer. The weight average molecular weight of the acrylic oligomer was 5100, and the glass transition temperature (Tg) was 130 ° C.

(D2) Preparation of prepolymer composition 43 parts by mass of lauryl acrylate, 44 parts by mass of 2-ethylhexyl acrylate, 6 parts by mass of 4-hydroxybutyl acrylate, and 7 parts by mass of N-vinyl-2-pyrrolidone, and as a photopolymerization initiator. A prepolymer composition (polymerization rate: about 10%) was obtained by mixing 0.015 parts by mass of "Irgacure 184" manufactured by BASF and irradiating with ultraviolet rays to carry out polymerization.

(D3) Preparation of Acrylic Adhesive To 100 parts by mass of the above prepolymer composition, 0.07 parts by mass of 1,6-hexanediol diacrylate, 1 part by mass of the above acrylic oligomer, and a silane coupling agent (Shinetsu). Chemical "KBM403J") 0.3 parts by mass was added and mixed uniformly to prepare an acrylic pressure-sensitive adhesive.

(E) Formation of First Decorative Layer 112a A frame by screen printing is used as the first Decorative Layer 112a on the main surface of the polarizing film 111 obtained in the above (b) opposite to the protective film 114. A shaped ink layer (width 15 mm, thickness 6 μm) was provided. Moisture permeability when the thickness 25μm of the first decorative layer 112a obtained by above procedure was 1135g ^/ m 2 · 24h.

The inks constituting the first decorative layer 112a are a dissolving type fluorescent pigment (manufactured by Teikoku Inks Manufacturing Co., Ltd., MIX-HF screen ink), a curing agent (manufactured by Teikoku Inks Manufacturing Co., Ltd., 210 curing agent), and a solvent ( Prepared by mixing with C-002 solvent manufactured by Teikoku Printing Inks. The concentrations of the soluble fluorescent pigment and the curing agent in the ink were 85% by mass and 3% by mass, respectively. The soluble fluorescent pigment and the curing agent were uniformly dispersed in the ink. The ink was in a uniform state with no precipitation or agglutination even when left at 5 ° C. overnight.

(F) Preparation of Optical Film 10 Laminated body (position) of the polarizing film having the first decorative layer 112a formed on the main surface of the polarizer 111 obtained in (e) above and the retardation layer obtained in (c). The retardation film 12) was continuously bonded by the roll-to-roll method using the acrylic pressure-sensitive adhesive obtained in (d). At this time, the retardation film 12 was bonded so that the first retardation layer was located on the polarizer side. The layers were laminated so that the axis angle between the slow-phase axis and the absorption axis was 45 °. In this way, the optical film 10 was produced. The thickness of the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer 113a) composed of the acrylic pressure-sensitive adhesive was 25 μm. Moisture permeability when the thickness 25μm of the first adhesive layer 113a obtained by the above-described procedure was 4678g ^/ m 2 · 24h.

(G) Attachment of Glass Plate S On the main surface (main surface on the second retardation layer side) of the retardation film 12 of the optical film 10 obtained in (f) above, which is opposite to the polarizer 111, ( The acrylic pressure-sensitive adhesive obtained in d) was applied, and a glass plate S (manufactured by Matsunami Glass Ind., S200243 MICRO SLIDE GLASS, thickness 1.2 mm) was attached to the optical film 10 via this pressure-sensitive adhesive. In this way, a sample having the layer structure shown in FIG. 3 was prepared.

(2) Evaluation The sample prepared in (1) above was held in a high temperature and high humidity environment (60 ° C. ± 1 ° C. and relative humidity 90% ± 2%) for 175 hours. Next, the decolorization of the polarizer 111 in the sample was evaluated by the following procedure.

The decolorization of the polarizer 111 was evaluated by Raman spectroscopy under the following conditions. More specifically, the sample is fixed so that the polarizer 111 can be analyzed from the protective film 114 side, and the region of the length 550 μm and the width 50 μm is focused inward from the end face of the polarizer 111. Mapping analysis was performed from the protective film 114 side (visual side in the display device). The Raman spectrum was measured at a total of four points where the distance from the end face of the polarizer 111 was 50 μm, 100 μm, 250 μm, and 500 μm.
Measuring device: SNOM / AFM / Raman multifunction device (WItec alpha300RSA)
Excitation wavelength: 532 nm
Measurement wavelength range: 125 cm ^{-1 to} 3800 ^{cm -1}
Objective lens: 10x Measurement pitch: 2 μm
Detector: EMCCD

<< Comparative Example 1 >>
In the first embodiment, the first decorative layer 112a was not formed on the main surface of the polarizer 111, but was formed in a state of being adhered to the peripheral edge of the main surface of the retardation film 112 on the first retardation layer side. .. Except for this, an optical film 10 was prepared and a sample was prepared by attaching a glass plate S in the same manner as in Example 1, and evaluation was performed.

<< Comparative Example 2 >>
In Example 1, as the protective film 114, a triacetyl cellulose film (thickness 40 μm) was used instead of the acrylic film. Except for this, an optical film 10 was prepared in the same manner as in Example 1, and a sample was prepared by attaching a glass plate S and evaluated. In this case, the moisture permeability at a thickness 25μm of the protective film 114 obtained by above procedure was 2151g ^/ m 2 · 24h.

The Raman spectra of Example 1 and Comparative Example 1 are shown in FIGS. 4 and 5, respectively. In each of these figures, the Raman spectrum at each measurement point is represented from top to bottom in the order in which the distance between the measurement points is closer to the end face of the polarizer 111. The Raman spectra of polarizers containing iodine, Raman shift is at a position of the 106cm ^-1 and 156cm ^-1, _{I 5} ^- and _{I 3} ^- Raman lines based on is observed. As shown in FIG. 5, in Comparative Example 1, at the innermost measurement point of the polarizer 111, the Raman line based on _{I 5} ⁻ and I ₃ ^{− was formed even after the sample was exposed to a high temperature and high humidity environment for a long time.} that observed, in the other measuring point I ₅ ^- and I ₃ ^- Raman lines based on is not observed. On the other hand, in Example 1, as shown in FIG. 4, Raman lines based on _{I 5} ⁻ and I ₃ ⁻ were observed at all measurement points even after the sample was exposed to a high temperature and high humidity environment for a long time. NS. At the measurement point closest to the end face, _{the intensity of the Raman line based on I 5} ⁻ and I ₃ ⁻ is less than that at the innermost measurement point, and slight decolorization is observed. However, it can be said that the decolorization of the polarizer 111 is remarkably reduced as compared with Comparative Example 1.
As for Comparative Example 2, the same result as that of Comparative Example 1 can be obtained.

1,101: Flexible image display device 10: Optical film 11: Polarizing film 111: Polarizer 112a: First decorative layer 112b: Second decorative layer 113a: First adhesive layer 113b: Second adhesive layer 114: Protective film 115: Adhesive layer 12: Phase difference film 13: Window member 131: Window film 132: Hard coat layer 14: Touch sensor 15: Panel members 22, 23: Adhesive layer

Claims (10)

Polarizer and
A first decorative layer and a first adhesive layer adhered to one main surface of the polarizer,
A second decorative layer and a second adhesive layer, or a protective film, which are adhered to the other main surface of the polarizer, are provided.
The first decorative layer is directly adhered to the peripheral edge of one of the main surfaces without an adhesive layer.
The first adhesive layer is formed so as to cover a surface of the first decorative layer opposite to the polarizer and a region of the one main surface to which the first decorative layer is not adhered.
The second decorative layer is directly adhered to the peripheral edge of the other main surface without an adhesive layer.
The second adhesive layer is formed so as to cover a surface of the second decorative layer opposite to the polarizer and a region of the other main surface to which the second decorative layer is not adhered.
The protective film is directly adhered to the other main surface without an adhesive layer, or is adhered through an adhesive layer.
The first decorative layer, the second decorative layer, and wherein each of the protective film, the moisture permeability when the thickness of 25μm is not more than 1500 g ^/ m 2 · 24h, polarization film. After being held at 60 ° C. ± 1 ° C. and a relative humidity of 90% ± 2% for 175 hours, the polarizing film does not contain a bleached portion in or near the end face of the polarizing element. Or including decolorized parts,
The polarizing film according to claim 1, wherein when the polarizing film includes the decolorized portion, the decolorized portion is formed in a region where the distance from the end face is less than 100 μm. The polarizing film according to claim 1 or 2, wherein the width of each of the first decorative layer and the second decorative layer is 0.1 mm or more. The polarizing film according to any one of claims 1 to 3, wherein the thickness of each of the first decorative layer and the second decorative layer is 5 μm or more. The polarizing film according to any one of claims 1 to 4, wherein each of the first decorative layer and the second decorative layer contains an acrylic resin. The polarizing film according to any one of claims 1 to 5, wherein the protective film contains at least one selected from the group consisting of an acrylic resin and a cyclic olefin resin. The polarizing film according to any one of claims 1 to 6, wherein the protective film has a thickness of 40 μm or more. A polarizing film according to any one of claims 1 to 7 and at least one of a window member and a retardation film are provided.
The polarizing film includes a first main surface on the viewing side and a second main surface on the side opposite to the first main surface.
The window member is arranged on the first main surface side of the polarizing film.
The retardation film is an optical laminate arranged on the second main surface side of the polarizing film. The polarizing film according to any one of claims 1 to 7 and a panel member are provided.
The polarizing film includes a first main surface on the viewing side and a second main surface on the side opposite to the first main surface.
The panel member is an image display device arranged on the second main surface side. An image display device comprising the optical laminate according to claim 8 and a panel member arranged on the side opposite to the visual viewing side of the optical laminate.

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