Polarizing plate and image display device using the same

Abstract

This invention provides a polarizer that, despite having a low-resistance adhesive layer, is thin, exhibits excellent durability, suppresses unsightly appearance, and inhibits cracking during irregular shaping. The polarizer according to embodiments of this invention comprises: a polarizer, a protective layer disposed on one side of the polarizer, an iodine permeation suppression layer disposed on the other side of the polarizer, and an adhesive layer disposed on the side of the iodine permeation suppression layer opposite to the polarizer. The iodine permeation suppression layer is a cured or thermosetting film of a resin organic solvent solution coating. The adhesive composition constituting the adhesive layer includes a base polymer and an antistatic agent. The glass transition temperature of the base polymer is below -50°C, and its dielectric constant at 100 kHz is 5.0 or higher. The surface resistivity of the adhesive layer is 1.0 × 10⁻⁶. 9 Below Ω / □.

Description

Technical Field

[0001] This invention relates to polarizers and image display devices using the polarizers. Background Technology

[0002] Image display devices, represented by liquid crystal displays (LCDs) and electroluminescent (EL) displays (e.g., organic EL displays and inorganic EL displays), are rapidly gaining popularity. In image display devices, a polarizer is typically bonded to the display panel via an adhesive layer. In recent years, with the development of image display devices featuring narrower bezels and so-called in-wall image display devices that incorporate conductive layers for touch panels within the display panel, there has been a demand for improved antistatic properties. Consequently, there is a need for improved antistatic properties and lower resistance in the adhesive layer. However, polarizers using such adhesive layers suffer from reduced durability, poor appearance, and cracking when processed into irregular shapes other than rectangular.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-193371 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The present invention was made to solve the above-mentioned existing problems, and its main objective is to provide a polarizing sheet that, despite having a low-resistance adhesive layer, is thin, has excellent durability, suppresses poor appearance, and also suppresses cracking during irregular processing.

[0008] Problem Solving Methods

[0009] The polarizer according to an embodiment of the present invention comprises: a polarizer, a protective layer disposed on one side of the polarizer, an iodine permeation suppression layer disposed on the other side of the polarizer, and an adhesive layer disposed on the side of the iodine permeation suppression layer opposite to the polarizer. The iodine permeation suppression layer is a cured or thermosetting film of a resin organic solvent solution coating. The adhesive composition constituting the adhesive layer comprises a base polymer and an antistatic agent. The glass transition temperature of the base polymer is below -50°C, and the dielectric constant at 100 kHz is above 5.0. The surface resistivity of the adhesive layer is 1.0 × 10⁻⁶. 9 Below Ω / □.

[0010] In one embodiment, the base polymer comprises an alkoxy-containing monomer as a monomer component. In one embodiment, the base polymer comprises 20 to 99 parts by weight of the alkoxy-containing monomer relative to 100 parts by weight of all monomer components. In one embodiment, the alkoxy-containing monomer is represented by the following formula:

[0011] [Chemical Formula 1]

[0012]

[0013] In the formula, R 1 It is an alkyl group, and n is an integer from 1 to 15.

[0014] In one embodiment, the base polymer further comprises a hydroxyl-containing monomer as a monomer component.

[0015] In one embodiment, the content of the antistatic agent in the adhesive composition is 10 parts by weight or less relative to 100 parts by weight of the base polymer.

[0016] In one embodiment, the antistatic agent comprises lithium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide salt, or tributylmethylammonium bis(trifluoromethanesulfonyl)imide.

[0017] In one embodiment, the adhesive composition further comprises a silane coupling agent. In another embodiment, the adhesive composition further comprises an antioxidant.

[0018] In one embodiment, the adhesive layer has an adhesion force of 1.0 N / 25 mm or more to the glass.

[0019] In one embodiment, the resin constituting the iodine permeation inhibition layer comprises a copolymer obtained by polymerizing a monomer mixture, wherein the monomer mixture comprises more than 50 parts by weight of a (meth)acrylic acid monomer and more than 0 parts by weight and less than 50 parts by weight of a monomer represented by formula (1).

[0020] [Chemical Formula 2]

[0021]

[0022] (In the formula, X represents a functional group containing at least one reactive group selected from vinyl, (meth)acryloyl, styrene, (meth)acrylamido, vinyl ether, epoxy, oxetyl, hydroxyl, amino, aldehyde, and carboxyl groups; R...) 1 and R 2 Each can independently represent a hydrogen atom, an aliphatic hydrocarbon group with optional substituents, an aryl group with optional substituents, or a heterocyclic group with optional substituents, R 1and R 2 (Optional interconnections to form a loop).

[0023] In one embodiment, the total thickness of the polarizer is less than 60 μm.

[0024] According to other aspects of the present invention, an image display apparatus is provided, which includes the polarizer described above.

[0025] The effects of the invention

[0026] According to an embodiment of the present invention, by setting the adhesive layer in a polarizer having a low-resistance adhesive layer to a specific configuration, it is possible to achieve a thin polarizer with excellent durability, suppression of poor appearance (typically, expansion of the protective layer portion contained in the polarizer and cracking of the functional layer), and suppression of cracking during irregular processing. Attached Figure Description

[0027] Figure 1 This is a cross-sectional schematic diagram of a polarizer according to one embodiment of the present invention.

[0028] Symbol Explanation

[0029] 11. Polarizing mirror

[0030] 12 protective layers

[0031] 30 Adhesive layer

[0032] 40 Iodine permeates the inhibition layer

[0033] 100 polarizer Detailed Implementation

[0034] The embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0035] A. Overall Structure of Polarizing Film

[0036] Figure 1This is a cross-sectional schematic diagram of a polarizer according to one embodiment of the present invention. The polarizer 100 shown in the figure includes: a polarizer 11, a protective layer 12 disposed on one side of the polarizer 11, an iodine transmission suppression layer 40 disposed on the other side of the polarizer 11, and an adhesive layer 30 disposed on the side of the iodine transmission suppression layer 40 opposite to the polarizer 11. The iodine transmission suppression layer 40 is a cured or thermosetting film of a resin organic solvent solution coating. Other protective layers (not shown) may be disposed between the polarizer 11 and the iodine transmission suppression layer 40. Preferably, as shown in the example, the protective layer 12 is disposed only on one side of the polarizer 11. In this case, the iodine transmission suppression layer 40 is directly disposed on the polarizer 11 on the other side of the polarizer 11. In this specification, "directly disposed on the polarizer" means formed directly on the surface of the polarizer without an intervening adhesive layer (typically an adhesive layer or bonding agent layer). The adhesive layer 30 is provided as the outermost layer, and the polarizer can be adhered to the image display device (essentially the image display panel). In practical use, it is preferable to temporarily adhere a release film to the surface of the adhesive layer 30 until the polarizer is put into use. By temporarily adhering the release film, the adhesive layer can be protected, and a roll of polarizer can be formed.

[0037] In an embodiment of the present invention, the adhesive composition constituting the adhesive layer 30 comprises a base polymer and an antistatic agent. The base polymer has a glass transition temperature of -50°C or lower and a dielectric constant of 5.0 or higher at 100 kHz. By using such a base polymer, an adhesive layer with low surface resistivity can be achieved even with a low content of antistatic agent. That is, in an embodiment of the present invention, although the content of antistatic agent in the adhesive composition is less than 10 parts by weight relative to 100 parts by weight of the base polymer, the surface resistivity of the adhesive layer can reach 1.0 × 10⁻⁶. 9 Ω / □ or less. As a result, it is possible to achieve a thin, durable polarizer in which the appearance defects of the functional layers contained in the polarizer (e.g., iodine transmission suppression layer) are suppressed, and cracks during irregular processing are also suppressed.

[0038] The polarizer of the present invention may further include functional layers other than the iodine transmission suppression layer. A representative example of such a functional layer is a phase retardation layer. The optical properties (e.g., refractive index characteristics, in-plane phase retardation, Nz coefficient, photoelastic coefficient), thickness, and placement of the phase retardation layer can be appropriately set according to the purpose.

[0039] The polarizer in the embodiments of the present invention can be in sheet form or in strip form. In this specification, "strip form" refers to an elongated shape whose length is sufficiently long relative to its width, for example, including elongated shapes whose length is 10 times or more, preferably 20 times or more, than its width. The strip-shaped polarizer can be wound into a roll.

[0040] The polarizer of the embodiments of the present invention can have irregular shapes other than rectangles. In this specification, "having irregular shapes other than rectangles" means that the top view shape of the polarizer has a shape other than a rectangle. Typically, irregular shapes are irregularly shaped processing portions. Therefore, "polarizers having irregular shapes other than rectangles" includes not only cases where the entire polarizer (i.e., the outer edge that determines the top view shape of the film) is not rectangular, but also cases where irregularly shaped processing portions are formed in portions spaced inward from the outer edge of a rectangular polarizer. When using an adhesive layer with low surface resistivity (low-resistance adhesive layer), the added antistatic agent acts as a plasticizer. In such irregularly shaped processing portions, the polarizer is prone to cracking because the polarizer shrinks in a high-temperature environment. However, according to the embodiments of the present invention, such cracking can be significantly suppressed. Examples of irregular shapes (irregularly shaped processing portions) include: through holes, chamfered corners, and cutting portions that are concave when viewed from above. Representative examples of concave portions include shapes resembling boat shapes, shapes resembling bathtub shapes, V-shaped notches, and U-shaped notches. As another example of an irregularly shaped (irregularly shaped processing section), a shape corresponding to a car dashboard can be cited. In this shape, the outer edge is formed as an arc along the rotation direction of the instrument needle, and includes a portion where the outer edge protrudes inward in a V-shape (including an arc). The shape of the irregularly shaped section is not limited to the examples described above; any suitable shape appropriate to the purpose can be used. For example, as the shape of a through-hole, a circle, ellipse, triangle, quadrilateral, pentagon, hexagon, or octagon can be used. Furthermore, the through-hole can be provided at any suitable position depending on the purpose. The through-hole can be provided at approximately the center of the longitudinal end of a rectangular polarizer, at a given position at the longitudinal end, or at a corner of the polarizer; it can also be provided at the short side end of the rectangular polarizer; or it can be provided at the center of a polarizer that has an overall irregular shape. The irregularly shaped processing section can be formed by combining the above examples. For example, a through-hole can be formed by combining a V-shaped notch and / or a U-shaped notch.

[0041] The total thickness of the polarizer is preferably 60 μm or less, more preferably 55 μm or less, further preferably 50 μm or less, and particularly preferably 40 μm or less. The lower limit of the total thickness can be, for example, 28 μm. According to embodiments of the present invention, in a configuration having a low-resistance adhesive layer and a protective layer only on one side of the polarizer, the same effect as a configuration having protective layers on both sides of the polarizer can be obtained. As a result, since a protective layer can be omitted, significant thinning can be achieved. If the total thickness of the polarizer is within such a range, the generation of bubbles, referred to as so-called delayed bubbles, can be significantly suppressed. Delayed bubbles refer to bubbles generated under the following conditions: for example, in the case of attaching a polarizer with through-holes to the visible side of an image display panel, and in the case of attaching a cover glass to the visible side of the polarizer. The cover glass is attached via a given adhesive and by vacuum lamination. In this case, the through-holes can be filled by the adhesive. Immediately after vacuum lamination, no identifiable air bubbles are usually present in the filled portion. However, air bubbles sometimes appear during subsequent heat durability tests of the image display device. Such bubbles are typically caused by the shrinkage stress of the polarizer applied to the filled portion. These bubbles are called delayed bubbles. Delayed bubbles are not microscopic bubbles, but large bubbles occupying a certain proportion or more of the top-view area of ​​the through-hole. They are unacceptable both from an aesthetic point of view and from the perspective of camera performance of the camera unit located at the position corresponding to the through-hole. Therefore, suppressing delayed bubbles has high industrial value. It should be noted that the total thickness of the polarizer refers to the sum of the thickness of the polarizer, protective layer, iodine transmission suppression layer, and adhesive layer or bonding agent layer used to laminate them (i.e., the total thickness of the polarizer does not include the thickness of the adhesive layer 30 and the release film that can be temporarily attached to the surface).

[0042] The following is a more detailed explanation of the components of a polarizer.

[0043] B. Polarizing filter

[0044] Typically, the polarizer is formed of a resin film containing a dichroic substance (typically iodine). Any suitable resin film suitable for use as a polarizer can be used as the resin film. Typically, the resin film is a polyvinyl alcohol resin (hereinafter referred to as "PVA-type resin") film. The resin film can be a single-layer resin film or a laminate of two or more layers.

[0045] As a specific example of a polarizer composed of a single-layer resin film, a polarizer made by dyeing and stretching a PVA-type resin film using iodine (typically uniaxial stretching) can be cited. The dyeing using iodine can be performed, for example, by immersing the PVA-type film in an aqueous iodine solution. The stretching magnification of the uniaxial stretching is preferably 3 to 7 times. Stretching can be performed after dyeing or during dyeing. Alternatively, dyeing can be performed after stretching. The PVA-type resin film can be subjected to swelling treatment, cross-linking treatment, cleaning treatment, drying treatment, etc., as needed. For example, by immersing the PVA-type resin film in water for washing before dyeing, not only can dirt and anti-blocking agents on the surface of the PVA-type film be washed away, but the PVA-type resin film can also swell to prevent uneven dyeing.

[0046] Specific examples of polarizers obtained using laminates include: a laminate consisting of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate consisting of a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizer obtained using a laminate consisting of a resin substrate and a PVA-based resin layer coated on the resin substrate can be manufactured by, for example, coating a PVA-based resin solution onto a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, obtaining a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to form a polarizer from the PVA-based resin layer. In this embodiment, it is preferable to form a polyvinyl alcohol resin layer comprising a halide and a polyvinyl alcohol resin on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Furthermore, stretching may, as needed, further include stretching the laminate in a gas atmosphere at a high temperature (e.g., above 95°C) before stretching in the aqueous boric acid solution. Furthermore, in this embodiment, it is preferable to subject the laminate to a drying shrinkage treatment, in which it is heated while being transported along its length, causing it to shrink by 2% or more in its width direction. Typically, the manufacturing method of this embodiment includes sequentially subjecting the laminate to assisted stretching in a gas atmosphere, dyeing, stretching in an aqueous solution, and drying shrinkage treatment. By introducing assisted stretching, even when PVA is coated on a thermoplastic resin, the crystallinity of PVA can be improved, thereby achieving high optical properties. Additionally, by simultaneously improving the orientation of PVA beforehand, problems such as decreased orientation and dissolution of PVA can be prevented when immersed in water during subsequent dyeing and stretching processes, thus achieving high optical properties. Furthermore, when the PVA resin layer is immersed in a liquid, compared to when the PVA resin layer does not contain halides, the orientation disorder and decrease in orientation of polyvinyl alcohol molecules can be suppressed. Therefore, the optical properties of the polarizer obtained by immersing the laminate in a liquid through dyeing and stretching in an aqueous solution can be improved. Furthermore, the drying shrinkage treatment, which shrinks the laminate in its width direction, can improve optical properties. The resulting resin substrate / polarizer laminate can be used directly (i.e., the resin substrate can be used as a protective layer for the polarizer), or the resin substrate can be peeled off from the resin substrate / polarizer laminate, and any suitable protective layer conforming to the purpose can be laminated on the peeled surface for use. Detailed descriptions of such a polarizer manufacturing method are provided, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0047] The thickness of the polarizer is preferably 1 μm to 10 μm, more preferably 1 μm to 8 μm, and even more preferably 2 μm to 5 μm. If the thickness of the polarizer is within this range, it can make a significant contribution to the thinning of the polarizer.

[0048] The polarizer preferably exhibits absorption dichroism at any wavelength within the range of 380 nm to 780 nm. The single-unit transmittance of the polarizer is preferably 41.5% to 46.0%, more preferably 43.0% to 46.0%, and even more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or higher, more preferably 99.0% or higher, and even more preferably 99.9% or higher.

[0049] C. Protective layer

[0050] The protective layer 12 (and other protective layers if present) can be formed from any suitable film that can be used as a protective layer for a polarizer. Specific examples of materials that are the main components of this film include: cellulose resins such as cellulose triacetate (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, polysulfones, polystyrene, polynorbornene, polyolefins, (meth)acrylic acids, acetates, and other transparent resins. Additionally, thermosetting resins or UV-curing resins such as (meth)acrylic acids, urethanes, (meth)acrylate urethanes, epoxy resins, and silicone resins can also be used. Furthermore, glassy polymers such as siloxane polymers can also be used. Additionally, polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As the material for this membrane, resin compositions can be used, for example, thermoplastic resins containing substituted or unsubstituted imide groups on the side chains, and thermoplastic resins containing substituted or unsubstituted phenyl and nitrile groups on the side chains. Examples include resin compositions having alternating copolymers formed from isobutylene and N-methylmaleimide, and acrylonitrile-styrene copolymers. The polymer membrane can be, for example, an extruded product of the above-mentioned resin compositions.

[0051] When the polarizer is positioned on the viewable side of the image display device, the protective layer 12 is typically positioned on that viewable side. In this case, the protective layer 12 may be subjected to surface treatments such as hard coating, anti-reflective treatment, anti-adhesion treatment, and anti-glare treatment as needed.

[0052] The thickness of the protective layer is preferably 10 μm to 50 μm, more preferably 15 μm to 35 μm. It should be noted that, when surface treatment is performed, the thickness of the outer protective layer includes the thickness of the surface treatment layer.

[0053] D. Iodine permeates the inhibitory layer

[0054] In embodiments of the present invention, by providing an iodine permeation suppression layer, the increase in surface resistivity of the adhesive layer under high temperature and / or high temperature / high humidity conditions can be suppressed, and cracks during irregular processing can be suppressed. As described above, the iodine permeation suppression layer is a cured or thermosetting film of a resin organic solvent solution coating. With such a configuration, the thickness can be made very thin (e.g., less than 10 μm). The thickness of the iodine permeation suppression layer is preferably 0.05 μm to 10 μm, more preferably 0.08 μm to 5 μm, further preferably 0.1 μm to 1 μm, and particularly preferably 0.2 μm to 0.7 μm. Furthermore, with such a configuration, the iodine permeation suppression layer can be formed directly on the polarizer (i.e., without the inclusion of an adhesive layer or bonding agent layer). According to embodiments of the present invention, as described above, since the polarizer and the iodine permeation suppression layer are very thin, the adhesive layer or bonding agent layer used for laminating the iodine permeation suppression layer can be omitted, and therefore, the total thickness of the polarizer can be reduced to a very thin thickness. Furthermore, compared to cured aqueous coatings such as aqueous solutions or dispersions, this iodine transmission-inhibiting layer exhibits lower hygroscopicity and permeability, thus providing excellent humidification durability. As a result, it is possible to achieve polarizers with excellent durability that maintain optical properties even under high temperature and humidity environments. Additionally, compared to cured products such as those using UV-curable resins, this iodine transmission-inhibiting layer can suppress adverse effects on the polarizer (polarizer) caused by UV irradiation. The iodine transmission-inhibiting layer is preferably a cured coating of an organic solvent solution of resin. Compared to cured products, cured products exhibit less shrinkage during film formation and are free of residual monomers, thus suppressing film degradation and adverse effects on the polarizer (polarizer) caused by residual monomers.

[0055] The glass transition temperature (Tg) of the resin constituting the iodine permeation suppression layer is typically 85°C or higher, preferably 90°C or higher, more preferably 100°C or higher, further preferably 110°C or higher, particularly preferably 120°C or higher, and the upper limit of Tg can be, for example, 200°C. The weight-average molecular weight (Mw) of the resin is typically 25,000 or higher, preferably 30,000 or higher, more preferably 35,000 or higher, further preferably 40,000 or higher, and the upper limit of Mw can be, for example, 150,000. If the Tg and Mw of the resin are within such ranges, the synergistic effect with the effect of the iodine permeation suppression layer formed by the cured or thermosetting material of the coating film of the resin-exposed organic solvent solution can significantly suppress the migration of iodine from the polarizer to the image display panel, even though it is very thin. As a result, when the polarizer is applied to an image display device, corrosion of the metal components of the image display device can be significantly suppressed.

[0056] As the resin constituting the iodine permeation inhibition layer, any suitable thermoplastic or thermosetting resin can be used. A thermoplastic resin is preferred. Examples of thermoplastic resins include acrylic resins and epoxy resins; combinations of acrylic and epoxy resins can also be used. Representative examples of acrylic and epoxy resins that can be used in the iodine permeation inhibition layer will be described below.

[0057] Acrylic resins typically contain repeating units from (meth)acrylate monomers having a linear or branched structure as the main component. In this specification, (meth)acrylate refers to acrylic acid and / or methacrylic acid. Acrylic resins may contain repeating units from any suitable comonomer appropriate for the purpose. Examples of comonomers include, for instance, carboxyl-containing monomers, hydroxyl-containing monomers, amide-containing monomers, aromatic ring (meth)acrylates, and heterocyclic vinyl monomers. By appropriately setting the type, quantity, combination, and copolymerization ratio of the monomer units, acrylic resins having the given Mw can be obtained.

[0058] <Boron-containing acrylic resins>

[0059] In one embodiment, the acrylic resin comprises a copolymer (hereinafter, sometimes referred to as boron-containing acrylic resin) obtained by polymerizing a monomer mixture, wherein the monomer mixture comprises more than 50 parts by weight of (meth)acrylic monomer and more than 0 parts by weight and less than 50 parts by weight of monomer represented by formula (1) (hereinafter, sometimes referred to as comonomer).

[0060] [Chemical Formula 3]

[0061]

[0062] (In the formula, X represents a functional group containing at least one reactive group selected from vinyl, (meth)acryloyl, styrene, (meth)acrylamido, vinyl ether, epoxy, oxetyl, hydroxyl, amino, aldehyde, and carboxyl groups; R...) 1 and R 2 Each can independently represent a hydrogen atom, an aliphatic hydrocarbon group with optional substituents, an aryl group with optional substituents, or a heterocyclic group with optional substituents, R 1 and R 2 (Optional interconnections to form a loop).

[0063] Boron-containing acrylic resins typically have repeating units represented by the following formula. By polymerizing a monomer mixture comprising a comonomer represented by formula (1) and a (meth)acrylic monomer, the boron-containing acrylic resin has boron-containing substituents (e.g., repeating units of k in the following formula) in its side chains. This allows for improved adhesion to the polarizer when the iodine permeation suppression layer is positioned adjacent to it. The boron-containing substituents can be contained continuously (i.e., block-shaped) or randomly in the boron-containing acrylic resin.

[0064] [Chemical Formula 4]

[0065]

[0066] (where R is in the formula) 6 Let j represent any functional group, and k represent integers greater than or equal to 1.

[0067] <(meth)acrylic acid monomers>

[0068] As a (meth)acrylic acid monomer, any suitable (meth)acrylic acid monomer can be used. Examples include (meth)acrylic acid ester monomers having a straight-chain or branched structure, and (meth)acrylic acid ester monomers having a cyclic structure.

[0069] Examples of (meth)acrylate monomers having a straight-chain or branched structure include: methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, methyl 2-ethylhexyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. Methyl (meth)acrylate is preferred. Only one type of (meth)acrylate monomer may be used, or two or more may be used in combination.

[0070] Examples of cyclic (meth)acrylate monomers include: cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantane (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, biphenyl (meth)acrylate, o-bisphenoxyethyl (meth)acrylate, o-bisphenoxyethoxyethyl (meth)acrylate, m-bisphenoxyethyl (meth)acrylate, and p-bisphenoxyethyl (meth)acrylate. The monomers used include esters, o-biphenyloxy-2-hydroxypropyl methacrylate, p-biphenyloxy-2-hydroxypropyl methacrylate, m-biphenyloxy-2-hydroxypropyl methacrylate, N-(meth)acryloyloxyethyl o-biphenyl-urethane, N-(meth)acryloyloxyethyl p-biphenyl-urethane, N-(meth)acryloyloxyethyl m-biphenyl-urethane, o-phenylphenol glycidyl ether acrylate, etc., containing biphenyl monomers, terphenyl acrylate, o-terphenyloxyethyl methacrylate, etc. Preferably, 1-adamantane methacrylate and dicyclopentyl methacrylate are used. By using these monomers, polymers with high glass transition temperatures can be obtained. Only one of these monomers can be used, or two or more can be used in combination.

[0071] Alternatively, silsesquioxane compounds having (meth)acryloyl groups can be used instead of the aforementioned (meth)acrylate monomers. By using silsesquioxane compounds, acrylic polymers with high glass transition temperatures can be obtained. Silsesquioxane compounds are known to have various skeletal structures, such as cage-like, ladder-like, and random structures. Silsesquioxane compounds may have only one of these structures or two or more of them. Silsesquioxane compounds may use only one type or a combination of two or more types.

[0072] As silsesquioxane compounds containing (meth)acryloyl groups, examples include MAC and AC grades from the SQ series manufactured by Toa Synthetic Industries, Ltd. MAC grade compounds are silsesquioxane compounds containing methacryloyl groups, such as MAC-SQ TM-100, MAC-SQ SI-20, and MAC-SQ HDM. AC grade compounds are silsesquioxane compounds containing acryloyl groups, such as AC-SQ TA-100 and AC-SQ SI-20.

[0073] More than 50 parts by weight of (meth)acrylic monomers can be used relative to 100 parts by weight of the monomer mixture.

[0074] <Comonomer>

[0075] The monomer represented by formula (1) above is used as the comonomer. By using such a comonomer, boron-containing substituents can be introduced into the side chains of the resulting polymer. Only one comonomer can be used, or two or more can be used in combination.

[0076] Examples of aliphatic hydrocarbon groups in formula (1) above include straight-chain or branched alkyl groups with 1 to 20 carbon atoms that optionally have substituents, cyclic alkyl groups with 3 to 20 carbon atoms that optionally have substituents, and alkenyl groups with 2 to 20 carbon atoms. Examples of aryl groups above include phenyl groups with 6 to 20 carbon atoms that optionally have substituents, and naphthyl groups with 10 to 20 carbon atoms that optionally have substituents. Examples of heterocyclic groups include 5-membered or 6-membered cyclic groups containing at least one heteroatom that optionally have substituents. It should be noted that R 1 and R 2 They can be connected to form a loop. R 1 and R 2 Preferably, it is a hydrogen atom, or a straight-chain or branched alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.

[0077] The reactive group contained in the functional group represented by X is selected from at least one of vinyl, (meth)acryloyl, styryl, (meth)acrylamido, vinyl ether, epoxy, oxetyl, hydroxyl, amino, aldehyde, and carboxyl groups. The reactive group is preferably (meth)acryloyl and / or (meth)acrylamido. By having these reactive groups, the adhesion to the polarizer can be further improved when the iodine permeation suppression layer is disposed adjacent to the polarizer.

[0078] In one embodiment, the functional group represented by X is preferably the functional group represented by ZY-. Here, Z represents a functional group containing at least one reactive group selected from vinyl, (meth)acryloyl, styryl, (meth)acrylamido, vinyl ether, epoxy, oxetyl, hydroxy, amino, aldehyde, and carboxyl, and Y represents phenylene or alkylene.

[0079] The following compounds can be used as comonomers.

[0080] [Chemical Formula 5]

[0081]

[0082] [Chemical Formula 6]

[0083]

[0084] The comonomer is used in an amount of more than 0 parts by weight and less than 50 parts by weight relative to 100 parts by weight of the monomer mixture. Preferably, it is 0.01 parts by weight or more and less than 50 parts by weight, more preferably 0.05 parts by weight to 20 parts by weight, even more preferably 0.1 parts by weight to 10 parts by weight, and particularly preferably 0.5 parts by weight to 5 parts by weight.

[0085] <Acrylic resins containing lactam rings, etc.>

[0086] In another embodiment, the acrylic resin may have repeating units containing a ring structure selected from lactam ring units, glutaric anhydride units, glutarimide units, maleic anhydride units, and maleimide (N-substituted maleimide) units. The acrylic resin may contain only one type of repeating unit containing a ring structure, or it may contain two or more types. The content of the repeating unit containing a ring structure in the acrylic resin is preferably 1 mol% to 50 mol%, more preferably 10 mol% to 40 mol%, and even more preferably 20 mol% to 30 mol%. It should be noted that the acrylic resin contains repeating units derived from the above-mentioned (meth)acrylic monomers as the main repeating units.

[0087] <Epoxy Resin>

[0088] As the epoxy resin, an epoxy resin having aromatic rings is preferred. Using an epoxy resin having aromatic rings improves the adhesion to the polarizer when the iodine permeation suppression layer is disposed adjacent to the polarizer. Furthermore, when the adhesive layer is disposed adjacent to the iodine permeation suppression layer, the anchoring force of the adhesive layer is improved. Examples of epoxy resins having aromatic rings include: bisphenol-type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; phenolic varnish-type epoxy resins such as phenolic varnish epoxy resin, cresol varnish epoxy resin, and hydroxybenzaldehyde phenolic varnish epoxy resin; multifunctional epoxy resins such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, and epoxidized polyvinylphenol; naphthol-type epoxy resins; naphthyl-type epoxy resins; and biphenyl-type epoxy resins. Bisphenol A type epoxy resin, biphenyl type epoxy resin, and bisphenol F type epoxy resin are preferred. Only one type of epoxy resin can be used, or two or more types can be used in combination.

[0089] An iodine permeation inhibition layer can be formed by coating an organic solvent solution of the resin described above, forming a coating film, and then curing or thermally curing the coating film. Any suitable method and condition can be used as the coating method, curing method, or curing conditions.

[0090] The iodine permeation inhibition layer (which is essentially an organic solvent solution of the aforementioned resin) may contain any suitable additives depending on the purpose. The type, quantity, combination, and amount of additives may be appropriately determined according to the purpose.

[0091] E. Adhesive layer

[0092] As described above, the surface resistivity of the adhesive layer 30 is 1.0 × 10⁻⁶. 9 Ω / □ or less, preferably 5.0 × 10 8 Ω / □ or less, more preferably 1.0×10 8 Ω / □ or less, preferably 7.0×10 7 Ω / □ or less, preferably 1.0 × 10 7 Below Ω / □. For example, the lower limit of surface resistivity can be 5.0 × 10⁻⁶. 5 Below Ω / □. As described above, according to embodiments of the present invention, an adhesive layer with low surface resistivity can be achieved despite a low content of antistatic agent.

[0093] The adhesive layer's adhesion to the glass is preferably 1.0 N / 25 mm or more, more preferably 1.5 N / 25 mm or more, and even more preferably 2.0 N / 25 mm or more. If the adhesion is within this range, the adhesion to the image display panel is excellent, and the reworkability is also excellent. For example, the upper limit of the adhesion force can be 6.0 N / 25 mm.

[0094] The thickness of the adhesive layer is preferably 2μm to 55μm, more preferably 2μm to 30μm, further preferably 5μm to 25μm, and particularly preferably 10μm to 20μm.

[0095] As described above, the adhesive composition constituting the adhesive layer comprises a base polymer and an antistatic agent. As described above, the glass transition temperature (Tg) of the base polymer is -50°C or lower, preferably -52°C or lower, more preferably -55°C or lower. The lower limit of the Tg of the base polymer can be, for example, -75°C. As described above, the dielectric constant of the base polymer at 100 kHz is 5.0 or higher, preferably 5.5 or higher, more preferably 6.0 or higher, further preferably 6.5 or higher, and particularly preferably 7.0 or higher. The upper limit of the dielectric constant of the base polymer can be, for example, 10.0. By using such a base polymer, an adhesive layer with low surface resistivity can be achieved despite a low content of antistatic agent. It should be noted that the Tg of the base polymer can be calculated in the form of the polymer's Tg obtained by converting the Tg of each monomer component using the polymerization ratio.

[0096] Examples of base polymers include (meth)acrylic acid polymers, urethane polymers, silicone polymers, and rubber polymers, with (meth)acrylic acid polymers being preferred. In this specification, (meth)acrylic acid polymers used as base polymers are sometimes referred to as (meth)acrylic acid base polymers.

[0097] (Meth)acrylic acid-based polymers preferably contain alkoxy-containing monomers as monomer components. Examples of alkoxy-containing monomers include monomers represented by the following formula.

[0098] [Chemical Formula 7]

[0099]

[0100] In the formula, R 1 The alkoxy group is an alkyl group, such as methyl or ethyl, and n is an integer from 1 to 15. As specified in the above formula, the alkoxy group is preferably linear. If the alkoxy group is linear, the Tg of the resulting (meth)acrylate base polymer can be within the desired range described above, thereby enabling the dielectric constant of the base polymer to be within the desired range described above. Base polymers containing monomers with cyclic structures may have excessively high Tg and / or excessively low dielectric constants. Specific examples of alkoxy-containing monomers include: methoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate. These alkoxy-containing monomers can be used alone or in combination of two or more. By using alkoxy-containing monomers as monomer components, base polymers with desired Tg and dielectric constants can be obtained. As a result, an adhesive layer with low surface resistivity can be achieved despite a low content of antistatic agent. The content of alkoxy-containing monomers in the base polymer is preferably 30 to 99 parts by weight relative to 100 parts by weight of all monomer components. The content of alkoxy-containing monomers may be, for example, 30 to 60 parts by weight, and for example, 30 to 50 parts by weight, and for example, 50 to 99 parts by weight, and for example, 60 to 99 parts by weight.

[0101] The (meth)acrylate base polymer preferably contains hydroxyl-containing monomers as monomer components. Examples of hydroxyl-containing monomers include: 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 methyl (4-hydroxymethylcyclohexyl)acrylate. From the viewpoint of improving the durability of the adhesive layer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred. The content of hydroxyl-containing monomers in the base polymer is preferably 1 to 5 parts by weight, more preferably 1 to 3 parts by weight, relative to 100 parts by weight of all monomer components.

[0102] (Meth)acrylate-based base polymers may contain alkyl (meth)acrylates as monomer components. Examples of alkyl (meth)acrylates include linear or branched alkyl (meth)acrylates with 1 to 18 carbon atoms in the alkyl group. Examples of alkyl groups include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, dodecyl, isotetradecyl, lauryl, tridecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, etc. Alkyl (meth)acrylates may be used alone or in combination. The average number of carbon atoms in the alkyl group is preferably 3 to 8, more preferably 3 to 6. The content of alkyl (meth)acrylates in the base polymer can be arbitrarily set as the remainder of the monomer components other than the alkyl (meth)acrylate.

[0103] (Meth)acrylic acid base polymers may be further incorporated with other monomer components (comonomers) as needed. Representative examples of comonomers include aromatic hydrocarbon monomers (e.g., phenyl methacrylate, phenoxyethyl methacrylate, benzyl methacrylate), carboxyl monomers (e.g., carboxyethyl methacrylate, carboxypentyl methacrylate, carboxypentyl methacrylate, itaconic acid, maleic acid, fumaric acid, butenoic acid), amino monomers (e.g., N,N-dimethylaminoethyl methacrylate), amide monomers (e.g., methacrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide), nitrile monomers (e.g., methacrylonitrile), polyfunctional monomers (e.g., hexanediol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate), epoxy monomers (e.g., glycidyl methacrylate), and heterocyclic monomers (e.g., acryloylmorpholine). The types, quantities, combinations, and blending amounts (contents) of comonomers can be appropriately set according to the purpose.

[0104] The weight-average molecular weight (Mw) of the (meth)acrylic acid-based polymer is preferably 1 million to 3 million, more preferably 2 million to 3 million, and even more preferably 2 million to 2.8 million. When the weight-average molecular weight (Mw) is less than 1 million, crack suppression may sometimes become insufficient, and when the weight-average molecular weight (Mw) exceeds 3 million, there may be an increase in viscosity and / or gelation during polymer polymerization.

[0105] As antistatic agents, inorganic cationic salts and organic cationic salts are representative examples.

[0106] Inorganic cation salts are specifically inorganic cation-anion salts. Representative examples of the cations constituting the cation portion of an inorganic cation salt include alkali metal ions. Specific examples include lithium ions, sodium ions, and potassium ions. Lithium ions are preferred. Therefore, lithium salts are preferred inorganic cation salts.

[0107] Examples of anions that constitute the anionic portion of inorganic cation salts 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 - , - O3S(CF2)3SO3 - , and anions represented by the following general formulas (1) to (4).

[0108] (1): (C n F 2n+1 SO2)2N - (n is an integer from 1 to 10),

[0109] (2): CF2(C m F 2m SO2)2N - (m is an integer from 1 to 10),

[0110] (3): - O3S(CF2) l SO3 - (l is an integer from 1 to 10),

[0111] (4): (C p F 2p+1 SO2)N - (C q F 2q+1 SO2 (p and q are integers from 1 to 10).

[0112] Preferably, it contains fluorine anions, and more preferably, it contains fluorinated imide anions.

[0113] Examples of fluorinated imide anions include, for example, imide anions having a perfluoroalkyl group. As specific examples, (CF3SO2)(CF3CO)N mentioned above... - And anions represented by general formulas (1), (2) and (4).

[0114] (1): (C n F 2n+1 SO2)2N - (n is an integer from 1 to 10),

[0115] (2): CF2(C m F 2m SO2)2N- (m is an integer from 1 to 10),

[0116] (4): (C p F 2p+1 SO2)N - (C q F 2q+1 SO2 (p and q are integers from 1 to 10).

[0117] Preferably (CF3SO2)2N - (C2F5SO2)2N - (Perfluoroalkylsulfonyl)imide represented by general formula (1), more preferably (CF3SO2)2N - The term refers to bis(trifluoromethanesulfonyl)imide. Therefore, the preferred inorganic cation salt that can be used in embodiments of the present invention is lithium bis(trifluoromethanesulfonyl)imide.

[0118] Organic cationic salts are specifically organic cationic-anionic salts. Representative examples of the cations constituting the cation portion of organic cationic salts include those formed through substitution with organic groups. Organic salt ions Salt. As an organic In salt Salts, for example, include nitrogen-containing salts. Salt, sulfur Salt, phosphorus Salt. Preferably nitrogen-containing. Salt, sulfur Salt. As a nitrogen-containing... Salts, for example, include ammonium cations and piperidine. cationic, pyrrolidine Cations, Pyridine Cations, cations with a pyrrolidine skeleton, cations with a pyrrole skeleton, imidazole Cations, Tetrahydropyrimidine Cations, dihydropyrimidines cationic, pyrazole Cationic, pyrazoline Cations. As sulfur-containing Salts, for example, sulfonium cations. As phosphorus-containing... Salt, for example, can be cited as an example Cations. As organic Organic groups in the salt, for example, include alkyl, alkoxy, and alkenyl groups. Preferred organic groups... Specific examples of salts include tetraalkylammonium cations (e.g., tributylmethylammonium cations) and alkylpiperidines. cationic, alkylpyrrolidine Cation. The anion constituting the anionic portion of an organic cation salt is as described for the anion constituting the anionic portion of an inorganic cation. Preferred organic cation salts that can be used in embodiments of the present invention are 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide and trimethylbutylammonium bis(trifluoromethanesulfonyl)imide.

[0119] Inorganic cation salts can be used in combination with organic cation salts.

[0120] Relative to 100 parts by weight of the base polymer, the content of the antistatic agent in the adhesive composition is less than 10 parts by weight, as described above, preferably 7 parts by weight or less, more preferably 5 parts by weight or less, and even more preferably 3 parts by weight or less. According to embodiments of the invention, despite such a low content of antistatic agent, an adhesive layer with a low surface resistivity can be achieved. The lower limit of the antistatic agent content can be, for example, 0.5 parts by weight. When the antistatic agent content is too low, the desired surface resistivity value may not be obtained.

[0121] The adhesive composition typically contains a silane coupling agent, a crosslinking agent, and / or an antioxidant. Representative examples of silane coupling agents include functionalized silane coupling agents. Examples of functionalized groups include: epoxy, mercapto, amino, isocyanate, isocyanurate, vinyl, styryl, acetoacetyl, acylurea, thiourea, (meth)acrylate, heterocyclic, anhydride, and combinations thereof. Functionalized silane coupling agents can be used alone or in combination. Examples of crosslinking agents include isocyanate crosslinking agents and peroxide crosslinking agents. Crosslinking agents can also be used alone or in combination. The inclusion of a silane coupling agent provides the following advantages: Since the adhesive composition using a base polymer containing an alkoxy monomer has increased polarity, there is a possibility of insufficient adhesion to non-polar substrates. The inclusion of a silane coupling agent provides sufficient adhesion to various substrates, thereby suppressing peeling. Furthermore, the inclusion of an antioxidant provides the following advantages. The base polymer containing alkoxy monomers has a lower Tg, making it more flexible. The inclusion of antioxidants helps suppress shrinkage caused by oxidative degradation at the polarizer and adhesive layer ends.

[0122] Adhesive compositions may contain additives. Specific examples of additives include: colorants, pigments and other powders, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulates, and foils. Additionally, redox systems incorporating reducing agents can be used within a controllable range. The type, quantity, combination, and content of additives can be appropriately determined according to the intended purpose.

[0123] F. Image display device

[0124] The polarizers described in items A through E above can be applied to image display devices. Therefore, embodiments of the present invention include image display devices using such polarizers. Representative examples of image display devices include liquid crystal display devices and electroluminescent (EL) display devices (e.g., organic EL display devices and inorganic EL display devices). In one embodiment, the image display device is a narrow-bezel (preferably bezel-less) image display device or an embedded image display device. In such image display devices, the embodiments of the present invention exhibit significant advantages.

[0125] Example

[0126] The present invention will now be described in detail with reference to specific embodiments, but the present invention is not limited to these embodiments. The methods for measuring each characteristic are described below. It should be noted that, unless otherwise specified, "parts" and "%" in the embodiments and comparative examples are based on weight.

[0127] (1) Thickness

[0128] Thicknesses below 10 μm were measured using an interferometric film thickness gauge (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by AnritsuGS, product name "KC-351C").

[0129] (2) Surface resistivity

[0130] The surface resistance of the adhesive layer of the polarizers (polarizers with an adhesive layer) obtained in the examples and comparative examples was measured using an MCP-HT450 manufactured by Mitsubishi Chemical Analytech Co., Ltd., and used as the initial resistance value. The polarizers with the adhesive layer were then subjected to reliability tests under two different conditions (500 hours at 85°C and 500 hours at 60°C and 95% RH), and the resistance values ​​were measured in the same manner as described above. The rate of increase in resistance value was calculated using the following formula.

[0131] Resistance increase rate (%) = {(Resistance value after reliability test - Initial resistance value) / Initial resistance value} × 100

[0132] Furthermore, the evaluation was conducted according to the following criteria.

[0133] ○: Resistance increase rate is less than 50%

[0134] △: The rate of increase in resistance is greater than 50% but less than 1000%.

[0135] ×: Resistance increase rate is over 1000%

[0136] (3) ESD test

[0137] The polarizers (polarizers with adhesive layers) obtained in the examples and comparative examples were cut into 70mm × 150mm pieces and bonded to the liquid crystal panel via the adhesive layer. Next, silver paste was applied to the side surface of the bonded polarizer with adhesive layer, covering the entire thickness area of ​​the side surface of the polarizer with adhesive layer, and connected to an external ground electrode. Next, an ESD generator (ESD-8012A, manufactured by SANKI) (applied voltage 15kV) was used to emit (apply) 10 times at 1-second intervals on the surface of the polarizer with adhesive layer, in a circular motion within the polarizer surface, causing alignment disorder of the liquid crystal in the liquid crystal panel. The time it took for the white spots to disappear due to static electricity was measured and evaluated according to the following criteria.

[0138] ○: The white patches disappear within 5 seconds.

[0139] △: The white patches disappear within 10 seconds.

[0140] ×: White patches remain for more than 10 seconds.

[0141] (4) Delayed bubble

[0142] A 3.9 mm diameter through-hole was formed at the corner of the polarizer obtained in the examples and comparative examples using a vertical milling machine. This polarizer was then bonded to a glass plate via an adhesive layer, resulting in a polarizer / glass plate laminate A. Conversely, a conventional optical adhesive sheet (manufactured by Matsunami Glass Co., Ltd., 0.8 mm thick) was bonded to a cover glass using a roller laminator, resulting in a cover glass / optical adhesive laminate B. The polarizer of laminate A and the optical adhesive of laminate B were then bonded together using a vacuum laminator, with the two layers facing each other, and the through-hole was filled with optical adhesive. This produced an image display device prototype. The resulting image display device prototype was subjected to autoclave treatment and then a heating test (85°C, 24 h). The state of the bubbles after the test was observed by the naked eye or an optical microscope, and the results were evaluated according to the following criteria.

[0143] ○: No air bubbles were found in the filling section.

[0144] ×: Air bubbles were detected in the filling section.

[0145] (5) Decolorization

[0146] Test pieces (50mm × 50mm) were cut from the polarizers obtained in the examples and comparative examples, with two opposing sides, one along the absorption axis and the other along a direction orthogonal to the absorption axis. The test pieces were adhered to a glass plate via an adhesive layer and humidified by placing them in an oven at 65°C and 90% RH for 120 hours. The decolorization state of the humidified polarizer (essentially a polarizer) in an orthogonal Nicol configuration to a standard polarizer was examined using a microscope. Specifically, the amount of decolorization (decolorization amount: μm) from the end of the polarizer was measured. An Olympus MX61L microscope was used as the microscope, and images were taken at 10x magnification. The amount of decolorization at the corners was measured from the obtained images.

[0147] (6) Appearance

[0148] After the polarizers (50mm × 50mm polarizers) obtained in the examples and comparative examples were subjected to reliability testing (72 hours in an environment of 65°C and 90% RH), the appearance (including the overall appearance of the polarizer, such as the expansion of the protective layer and the state of the iodine permeation suppression layer) was observed by the naked eye and evaluated according to the following criteria.

[0149] ○: No issues were identified among expansion, peeling, cracks, and foreign matter.

[0150] △: Expansion, peeling, cracks, or foreign objects were confirmed in multiple locations.

[0151] ×: Multiple expansions, peeling, cracks, or foreign objects were identified overall.

[0152] (7) Cracks in irregularly shaped machining parts

[0153] A 3.9 mm diameter through-hole was formed at the corner of the polarizer obtained in the examples and comparative examples using a vertical milling machine. The polarizer with the through-hole was then bonded to a glass plate via an adhesive layer, serving as a test sample. This test sample was subjected to 300 cycles of thermal shock testing, involving holding at 85°C for 30 minutes followed by holding at -40°C for 30 minutes. The appearance of the through-hole portion after the test was observed visually, and the evaluation was performed according to the following criteria. It should be noted that no adhesive residue defects (end defects of the adhesive layer) occurred in any of the examples and comparative examples.

[0154] ○: No crack detected

[0155] ×: Crack confirmed

[0156] [Manufacturing Example 1: Preparation of (meth)acrylic acid-based basic polymer A1]

[0157] A monomer mixture containing 39 parts of butyl acrylate (BA), 60 parts of methoxyethyl acrylate (MEA), and 1 part of 4-hydroxybutyl acrylate (4HBA) was added to a four-necked flask equipped with a stirring blade, thermometer, nitrogen inlet tube, and condenser. Further, 0.1 parts of 2,2'-azobisisobutyronitrile (2,2'-ANOVA), acting as a polymerization initiator, were added along with 100 parts of ethyl acetate to 100 parts of this monomer mixture. After nitrogen purging by slowly stirring, the liquid temperature in the flask was maintained at approximately 55°C, and the polymerization reaction was carried out for 8 hours to prepare a solution of (meth)acrylic acid-based polymer A1. The Tg and dielectric constant of (meth)acrylic acid-based polymer A1 are shown in Table 1. It should be noted that the dielectric constant was determined using conventional methods. For Tg, the value was calculated based on the Tg of each monomer and converted using the polymerization ratio.

[0158] [Manufacturing Example 2: Preparation of (meth)acrylic acid-based basic polymer A2]

[0159] 60 parts of ethoxyethyl acrylate (EEEA) were used instead of 60 parts of MEA. Otherwise, a solution of (meth)acrylic acid-based polymer A2 was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of (meth)acrylic acid-based polymer A2 are shown in Table 1.

[0160] [Manufacturing Example 3: Preparation of (meth)acrylic acid-based basic polymer A3]

[0161] 60 parts of methoxytriethylene glycol acrylate (MTGA) were used instead of 60 parts of MEA. Otherwise, a solution of (meth)acrylic acid-based polymer A3 was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of (meth)acrylic acid-based polymer A3 are shown in Table 1.

[0162] [Manufacturing Example 4: Preparation of (meth)acrylic acid-based basic polymer A4]

[0163] A monomer mixture containing 99 parts MTGA and 1 part 4HBA was used, and a solution of (meth)acrylic acid-based polymer A4 was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of (meth)acrylic acid-based polymer A4 are shown in Table 1.

[0164] [Manufacturing Example 5: Preparation of (meth)acrylic acid-based basic polymer A5]

[0165] A monomer mixture containing 49 parts BA, 50 parts MTGA, and 1 part 4HBA was used. Otherwise, a solution of the (meth)acrylic acid-based polymer A5 was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of the (meth)acrylic acid-based polymer A5 are shown in Table 1.

[0166] [Manufacturing Example 6: Preparation of (meth)acrylic acid-based basic polymer A6]

[0167] A monomer mixture containing 69 parts BA, 30 parts MTGA, and 1 part 4HBA was used. Otherwise, a solution of (meth)acrylic acid-based polymer A6 was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of (meth)acrylic acid-based polymer A6 are shown in Table 1.

[0168] [Manufacturing Example 7: Preparation of (meth)acrylic acid-based basic polymer A7]

[0169] 50 parts of methoxy polyethylene glycol acrylate (MPEA) were used instead of 50 parts of MTGA. Otherwise, a solution of (meth)acrylic acid-based polymer A7 was prepared in the same manner as in Manufacturing Example 5. The Tg and dielectric constant of (meth)acrylic acid-based polymer A7 are shown in Table 1.

[0170] [Manufacturing Example 8: Preparation of (meth)acrylic acid-based basic polymer A8]

[0171] A solution of (meth)acrylic acid-based polymer A8 was prepared using a monomer mixture containing 79 parts BA, 20 parts MEA, and 1 part 4HBA, except that it was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of (meth)acrylic acid-based polymer A8 are shown in Table 1.

[0172] [Manufacturing Example 9: Preparation of (meth)acrylic acid-based basic polymer A9]

[0173] 50 parts of phenoxyethyl acrylate (PEA) were used instead of 50 parts of MTGA. Otherwise, a solution of (meth)acrylic acid-based polymer A9 was prepared in the same manner as in Manufacturing Example 5. The Tg and dielectric constant of (meth)acrylic acid-based polymer A9 are shown in Table 1.

[0174] [Manufacturing Example 10: Preparation of (meth)acrylic acid-based basic polymer A10]

[0175] 50 parts of tetrahydrofurfuryl acrylate were used instead of 50 parts of MTGA. Otherwise, a solution of (meth)acrylic acid-based polymer A10 was prepared in the same manner as in Manufacturing Example 5. The Tg and dielectric constant of (meth)acrylic acid-based polymer A10 are shown in Table 1.

[0176] [Manufacturing Example 11: Preparation of (meth)acrylic acid-based basic polymer A11]

[0177] 50 parts of (2-methyl-2-ethyl-1,3-dioxacyclopentan-4-yl) methyl acrylate were used instead of 50 parts of MTGA. Otherwise, a solution of (meth)acrylic acid-based polymer A11 was prepared in the same manner as in Manufacturing Example 5. The Tg and dielectric constant of (meth)acrylic acid-based polymer A11 are shown in Table 1.

[0178] [Manufacturing Example 12: Preparation of (meth)acrylic acid-based polymer A12]

[0179] 50 parts of (3-ethyloxetane-3-yl)methyl acrylate were used instead of 50 parts of MTGA. Otherwise, a solution of (meth)acrylic acid-based polymer A12 was prepared in the same manner as in Manufacturing Example 5. The Tg and dielectric constant of (meth)acrylic acid-based polymer A12 are shown in Table 1.

[0180] [Manufacturing Example 13: Preparation of (meth)acrylic acid-based basic polymer A13]

[0181] 50 parts of cyclotrimethylolpropane methyl acetal acrylate were used instead of 50 parts of MTGA. Otherwise, a solution of (meth)acrylic acid-based polymer A13 was prepared in the same manner as in Manufacturing Example 5. The Tg and dielectric constant of (meth)acrylic acid-based polymer A13 are shown in Table 1.

[0182] [Manufacturing Example 14: Preparation of (meth)acrylic acid-based polymer A14]

[0183] A monomer mixture containing 80.3 parts BA, 0.2 parts acrylic acid (AA), 16 parts PEA, 3 parts N-vinylpyrrolidone (NVP), and 0.5 parts 4HBA was used. Otherwise, a solution of the (meth)acrylic acid-based polymer A14 was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of the (meth)acrylic acid-based polymer A14 are shown in Table 1.

[0184] [Manufacturing Example 15: Preparation of (meth)acrylic acid-based basic polymer A15]

[0185] A monomer mixture containing 99 parts of BA and 1 part of 4HBA was used. Otherwise, a solution of (meth)acrylic acid-based polymer A15 was prepared in the same manner as in Manufacturing Example 1. The Tg and dielectric constant of (meth)acrylic acid-based polymer A15 are shown in Table 1.

[0186] [Manufacturing Example 16: Fabrication of Polarizer P1]

[0187] 1. Fabrication of a polarizing filter

[0188] As the thermoplastic resin substrate, a strip-shaped amorphous polyethylene terephthalate (PET) copolymer film with a water absorption rate of 0.75% and a Tg of approximately 75°C (thickness: 100 μm) was used. One side of the resin substrate was subjected to corona treatment.

[0189] Potassium iodide was added to 100 parts by weight of a PVA resin obtained by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z410") in a 9:1 ratio. The resulting mixture was then dissolved in water to prepare a PVA aqueous solution (coating solution).

[0190] The above-mentioned PVA aqueous solution was coated on the corona-treated surface of the resin substrate and dried at 60°C to form a PVA resin layer with a thickness of 13 μm, thus creating a laminate.

[0191] The resulting laminate was subjected to unidirectional stretching at its free end to 2.4 times its original length in a 130°C oven between rollers with different circumferential speeds (assisted stretching treatment in a gas atmosphere).

[0192] Next, the laminate is immersed in an insoluble bath at 40°C (an aqueous solution of boric acid prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insoluble treatment).

[0193] Next, the polarizer was immersed for 60 seconds in a staining bath at 30°C (an aqueous solution of iodine and potassium iodide prepared in a 1:7 weight ratio relative to 100 parts by weight of water) while adjusting the concentration to achieve a given value for the monomer transmittance (Ts) of the final polarizer.

[0194] Next, immerse in a crosslinking bath at 40°C (an aqueous solution of boric acid prepared by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (crosslinking treatment).

[0195] Then, while immersing the laminate in a boric acid aqueous solution (boric acid concentration 4.0 wt% and potassium iodide concentration 5 wt%) at a liquid temperature of 70°C, it was unidirectionally stretched (stretching treatment in aqueous solution) between rollers with different circumferential speeds along the longitudinal direction (length direction) to achieve a total stretch ratio of 5.5 times.

[0196] Then, the laminate was immersed in a cleaning bath at 20°C (an aqueous solution of 100 parts by weight of water and 4 parts by weight of potassium iodide) (cleaning treatment).

[0197] Then, it is dried in an oven maintained at 90°C while being in contact with SUS heated rollers with a surface temperature maintained at 75°C for approximately 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction caused by the drying shrinkage treatment is 5.2%.

[0198] Thus, a polarizer with a thickness of 5μm was formed on the resin substrate.

[0199] 2. Fabrication of Polarizing Films

[0200] An HC-TAC film as a protective layer was bonded to the surface of the polarizer (the side opposite to the resin substrate) obtained above using a UV-curable adhesive. Specifically, the adhesive was applied with a total thickness of 1.0 μm and bonded using a roller. Then, UV light was irradiated from the protective layer side to cure the adhesive. It should be noted that the HC-TAC film is a film with a 7 μm thick hard coating (HC) layer formed on a 25 μm thick cellulose triacetate (TAC) film, and the TAC film was bonded with the polarizer side facing outwards. Next, the resin substrate was peeled off, and an iodine permeation inhibition layer (0.3 μm thick) was formed on the peeled surface. It should be noted that the iodine permeation inhibition layer was formed as described below.

[0201] 97.0 parts of methyl methacrylate (MMA, manufactured by Fujifilm and Kohden Chemical Co., Ltd., trade name "methyl methacrylate monomer"), 3.0 parts of the comonomer represented by the above general formula (1e), and 0.2 parts of polymerization initiator (manufactured by Fujifilm and Kohden Chemical Co., Ltd., trade name "2,2'-azobisisobutyronitrile") were dissolved in 200 parts of toluene. Next, a polymerization reaction was carried out under a nitrogen atmosphere at 70°C for 5.5 hours to obtain a boron-containing acrylic resin solution (solids concentration: 33%). The obtained boron-containing acrylic polymer had a Tg of 110°C and a Mw of 80,000. 20 parts of this boron-containing acrylic polymer were dissolved in 80 parts of methyl ethyl ketone to obtain a resin solution (20%). The resin solution was applied to the release surface of the resin substrate using a bar coater, and the coated film was dried at 60°C for 5 minutes to form an iodine permeation inhibition layer in the form of a cured coating film of the resin organic solvent solution.

[0202] Thus, a polarizer P1 with a protective layer (HC layer / TAC film) / adhesive layer / polarizer / iodine transmission suppression layer was obtained.

[0203] [Manufacturing Example 17: Fabrication of Polarizer P2]

[0204] A 30 μm thick polyvinyl alcohol film was dyed for 1 minute at 30°C in a 0.3% iodine solution between rollers with different speed ratios, while being stretched to 3 times its original length. Then, it was immersed for 0.5 minutes in a 60°C aqueous solution containing 4% boric acid and 10% potassium iodide, while being stretched to a total stretch ratio of 6 times. Next, after cleaning by immersion in a 30°C aqueous solution containing 1.5% potassium iodide for 10 seconds, it was dried at 50°C for 4 minutes to obtain a 12 μm thick polarizer. An HC-TAC film was bonded to one side of this polarizer in the same manner as in Manufacturing Example 15. Then, an acrylic film (20 μm thick) with a lactam ring structure was bonded to the other side of the polarizer using a UV-curable adhesive (1.0 μm thick). Finally, an iodine permeation inhibition layer (0.3 μm thick) was formed on the surface of the acrylic film, in the same manner as in Manufacturing Example 16. Thus, a polarizer P2 was obtained, consisting of a protective layer (HC layer / TAC film), an adhesive layer, a polarizer, an adhesive layer, a protective layer (acrylic film), and an iodine permeation suppression layer.

[0205] [Manufacturing Example 18: Fabrication of Polarizing Film P3]

[0206] A cyclic olefin resin (COP) film (13 μm thick) was used instead of an acrylic film, and polarizer P3 was obtained in the same manner as in manufacturing example 17.

[0207] [Example 1]

[0208] 1. Preparation of adhesive composition

[0209] A solution of an acrylic adhesive composition was prepared by combining 100 parts of the solid component of the solution of the (meth)acrylic acid base polymer A1 obtained in Manufacturing Example 1 with 3 parts of an antistatic agent (trade name: LiTFSi30EA, manufactured by Mitsubishi Materials Corporation), 0.3 parts of benzoyl peroxide (trade name: Nyper BMT 40SV, manufactured by Nippon Yushi Co., Ltd.) as a crosslinking agent, 0.2 parts of an isocyanate crosslinking agent (trade name: Takenate D110N, manufactured by Mitsui Chemicals Co., Ltd.), 0.03 parts of a reworkability improver (trade name: SILYL SAT10, manufactured by Kaneka Corporation), 0.3 parts of an antioxidant (trade name: Irganox 1010, hindered phenol, manufactured by BASF Japan Co., Ltd.), and 0.2 parts of a silane coupling agent (trade name: A-100, manufactured by Soken Chemical Co., Ltd., acetyl acetyl silane coupling agent).

[0210] 2. Fabrication of polarizers with adhesive layer

[0211] The solution of the acrylic adhesive composition obtained above was coated on one side of a polyethylene terephthalate film (Mitsubishi Chemical Polyester Film, trade name "MRF38", separator) treated with an organosilicon release agent, and dried at 155°C for 1 minute, so that the thickness of the dried adhesive layer was 15 μm, thus forming an adhesive layer on the surface of the separator. Next, the adhesive layer formed on the separator was transferred to the surface of the iodine permeation suppression layer of the polarizer P1 prepared in Manufacturing Example 16, and a polarizer with an adhesive layer was prepared. The obtained polarizer with an adhesive layer was evaluated in (2) to (7) above, and the results are shown in Table 1.

[0212] [Examples 2-24 and Comparative Examples 1-12]

[0213] A polarizer with an adhesive layer was fabricated according to the combination of polarizer and adhesive layer shown in Table 1, and the results are shown in Table 1. It should be noted that the abbreviations for the antistatic agents in Table 1 are as follows.

[0214] LiTFSI: Lithium bis(trifluoromethanesulfonylimide)

[0215] EMI-FSI: 1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide salt

[0216] TBMA-TFSI: Tributylammonium bis(trifluoromethanesulfonyl)imide

[0217]

[0218] [evaluate]

[0219] As can be clearly seen from Table 1, the polarizers of the embodiments of the present invention exhibit good results in ESD tests and maintain low surface resistivity values ​​after reliability tests. Furthermore, in the polarizers of the embodiments of the present invention, any problems such as delayed bubbles, discoloration during humidification, poor appearance after reliability tests, and cracks during irregular processing are effectively suppressed.

[0220] Industrial applicability

[0221] The polarizer of the present invention can be applied to image display devices such as liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

Claims

1. A polarizer having: Polarizing lens A protective layer is set on one side of the polarizer. An iodine permeation suppression layer disposed on the other side of the polarizer, and An adhesive layer disposed on the side of the iodine permeation suppression layer opposite to the polarizer. The iodine permeation inhibition layer is a cured or heat-cured coating of an organic solvent solution of resin. The resin includes one or both of acrylic resins and epoxy resins. The thickness of the iodine permeation inhibition layer is greater than 0.5 μm and less than 10 μm. The adhesive composition constituting this adhesive layer includes a base polymer and an antistatic agent. The base polymer contains alkoxy-containing monomers as monomer components. The alkoxy-containing monomer is represented by the following formula. wherein R is an alkyl group and n is an integer from 1 to 15 1 wherein R is an alkyl group and n is an integer from 1 to 15 The glass transition temperature of this base polymer is below -50°C, and its dielectric constant at 100 kHz is above 5.

0. The surface resistance value of the adhesive layer is 1.0 x 10 9 Ω / □ or less.

2. The polarizer according to claim 1, wherein, The base polymer comprises 20 to 99 parts by weight of the alkoxy-containing monomer relative to 100 parts by weight of all monomer components.

3. The polarizer according to claim 1 or 2, wherein, The base polymer further includes hydroxyl-containing monomers as monomer components.

4. The polarizer according to claim 1 or 2, wherein, The content of the antistatic agent in the adhesive composition is less than 10 parts by weight relative to 100 parts by weight of the base polymer.

5. The polarizer according to claim 1 or 2, wherein, The antistatic agent comprises lithium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide salt, or tributylmethylammonium bis(trifluoromethanesulfonyl)imide.

6. The polarizer according to claim 1 or 2, wherein, The adhesive composition further comprises a silane coupling agent.

7. The polarizer according to claim 1 or 2, wherein, The adhesive composition further comprises an antioxidant.

8. The polarizer according to claim 1 or 2, wherein, The adhesive layer has an adhesion force of 1.0 N / 25 mm or more to the glass.

9. The polarizer according to claim 1 or 2, wherein, The resin constituting the iodine permeation inhibition layer comprises a copolymer obtained by polymerizing a monomer mixture comprising more than 50 parts by weight of a (meth)acrylic acid monomer and more than 0 parts by weight and less than 50 parts by weight of a monomer represented by formula (1). In the formula, X represents a functional group containing at least one reactive group selected from vinyl, (meth)acryloyl, styrene, (meth)acrylamido, vinyl ether, epoxy, oxetyl, hydroxyl, amino, aldehyde, and carboxyl groups, and R... 1 and R 2 Each can independently represent a hydrogen atom, an aliphatic hydrocarbon group with optional substituents, an aryl group with optional substituents, or a heterocyclic group with optional substituents, R 1 and R 2 They can be arbitrarily linked together to form a loop.

10. The polarizer according to claim 1 or 2, wherein the total thickness is less than 60 μm.

11. An image display device comprising a polarizer according to any one of claims 1 to 10.

Images