TW202033992A - Circularly polarizing plate and circularly polarizing plate with glass plate - Google Patents

Abstract

The purpose of the present invention is to provide: a circularly polarizing plate having good optical characteristics even after a wet heat test; and a circularly polarizing plate with a glass plate. This circularly polarizing plate has a linear polarizing layer, an attachment layer, and a [lambda]/4 retardation layer in this order, wherein: the linear polarizing layer contains a cured product of a polymerizable liquid crystal compound and a dichroic dye; and the [lambda]/4 retardation layer contains a cured product of a polymerizable liquid crystal compound. The moisture permeability of the attachment layer at a temperature of 40 DEG C and a humidity of 90%RH is 100 g/(m2.24hr) or less.

Description

Circular polarizing plate and circular polarizing plate with glass plate

The invention relates to a circular polarizing plate and a circular polarizing plate with a glass plate.

The linear polarizing layer, the circular polarizing plate, etc. are attached to image display elements such as liquid crystal cells or organic electroluminescence (EL) elements, and are assembled in display devices such as liquid crystal display devices or organic EL display devices. As the linear polarizing layer incorporated in this type of display device, there are known those in which dichroic dyes such as iodine are adsorbed and aligned to polyvinyl alcohol-based resin films, and those in which dichroic dyes are oriented in a cured polymer of liquid crystal compound. . In addition, as the retardation layer included in the circularly polarizing plate, a resin film having a retardation or one formed using a polymerizable liquid crystal compound is known.

In recent years, display devices have also been used as display devices for outdoor or in-vehicle use, and durability in harsher environments is required. Therefore, the linear polarizing layer, the circular polarizing plate, and the like incorporated in the display device are also required to have durability in harsher environments. For example, Patent Document 1 describes a laminate having improved durability in a high-temperature environment by providing moisture barrier layers on both sides of a linear polarizing plate with a low moisture content. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Korean Published Patent No. 10-2018-0031144

[The problem to be solved by the invention] The object of the present invention is to provide a circular polarizing plate and a circular polarizing plate with a glass plate that have good optical characteristics even after a wet heat test. [Means to solve the problem]

The present invention provides the following circular polarizing plates and circular polarizing plates with glass plates. [1] A circular polarizing plate having a linear polarizing layer, a bonding layer, and a λ/4 retardation layer in this order, the linear polarizing layer containing a cured product of a polymerizable liquid crystal compound and a dichroic dye, the λ The /4 retardation layer contains a cured product of a polymerizable liquid crystal compound, and the moisture permeability of the bonding layer at a temperature of 40° C. and a humidity of 90% RH is 100 g/(m ² ·24 hr) or less. [2] The circularly polarizing plate described in [1], wherein the λ/4 retardation layer has reverse wavelength dispersion. [3] The circular polarizing plate according to [1] or [2], wherein the bonding layer contains an adhesive composition. [4] The circular polarizing plate according to [3], wherein the adhesive composition contains a rubber-based polymer. [5] The circular polarizing plate according to any one of [1] to [4], which further has an outer coating on one or both sides of the linear polarizing layer. [6] The circular polarizing plate according to any one of [1] to [5], which further has a base layer on the side of the linear polarizing layer opposite to the side of the bonding layer. [7] The circular polarizing plate according to [6], which further has a hard coat layer on the side of the base layer opposite to the side of the linear polarizing layer. [8] The circularly polarizing plate according to any one of [1] to [7], which is for vehicle use. [9] A circularly polarizing plate with glass plates, which has glass plates on both sides of the circularly polarizing plate as described in any one of [1] to [8]. [Effects of the invention]

The circularly polarizing plate of the present invention can have good optical properties even after a wet heat test. Specifically, even after the damp heat test of the circular polarizer of the present invention, the phase difference value of the circular polarizer is not easy to change, and the reflectance is not easy to change when the circular polarizer is placed on the reflector.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all the drawings below, the scales are appropriately adjusted to make the constituent members easy to understand, and the scales of the constituent members shown in the drawings may not necessarily match the scales of the actual constituent members.

＜Circular Polarizing Plate＞ FIG. 1 is a schematic cross-sectional view schematically showing an example of the circularly polarizing plate 11 of this embodiment. As shown in FIG. 1, the circular polarizing plate 11 has a linear polarizing layer 33, a bonding layer 36, and a λ/4 retardation layer 38 in this order. The bonding layer 36 is an adhesive layer formed using an adhesive composition or an adhesive layer formed using an adhesive composition. In the circularly polarizing plate 11 shown in FIG. 1, the bonding layer 36 is provided on the linear polarizing layer 33 and the λ/4 retardation layer 38, and the linear polarizing layer 33 and the λ/4 retardation layer are bonded together. The situation is shown as an example.

The linear polarizing layer 33 contains a cured product of a polymerizable liquid crystal compound and a dichroic dye, and the dichroic dye is dispersed and aligned in the cured product of the polymerizable liquid crystal compound. The λ/4 retardation layer 38 contains a cured product of a polymerizable liquid crystal compound. The moisture permeability of the bonding layer 36 at a temperature of 40°C and a humidity of 90%RH is 100 g/(m ² ·24 hr) or less. The moisture permeability can be measured by the method described in the examples.

In this specification, the laminated layer having the moisture permeability refers to the layer existing between the linearly polarizing layer and the λ/4 retardation layer, and there is separation between the linearly polarizing layer and the λ/4 retardation layer In the case of a plurality of bonding layers arranged, it refers to the bonding layer existing on the side closest to the λ/4 retardation layer. If the moisture permeability of the bonding layer on the side closest to the λ/4 retardation layer is within the above range, it is easy to maintain good optical properties even after the wet heat test. In addition, the moisture permeability of the bonding layer refers to the moisture permeability of the entire multilayer structure when the bonding layer has a multilayer structure having two or more layers in direct contact.

The circularly polarizing plate 11 of this embodiment can suppress the reduction of the optical characteristic of the circularly polarizing plate 11 after a humid heat test even when the wet heat test is performed in the state which bonded the glass plate to the both surfaces. In the damp heat test, it is assumed that the display device for a vehicle is exposed to a damp heat environment. In addition, regarding the glass plates arranged on both sides of the circular polarizing plate 11 in the damp heat test, assuming that the circular polarizing plate 11 is used in an on-vehicle display device or the like, the image display element and touch panel bonded to the circular polarizing plate 11 Light-transmitting members with low moisture permeability used in control panels, front panels, etc.

In the circular polarizing plate 11 of the present embodiment, the reason why the decrease in optical characteristics after the wet heat test can be suppressed is presumed as follows. It is considered that if the glass plates are arranged on both sides of the circular polarizing plate 11 as described above, it is difficult for moisture to be discharged to the outside of the circular polarizing plate 11 and the circular polarizing plate 11 is likely to be covered by moisture. Therefore, it is estimated that in the circular polarizing plate 11 with glass plates provided on both sides, the movement of moisture and the like inside the circular polarizing plate 11 is likely to occur, and the optical characteristics are likely to be reduced due to this influence. Therefore, in the circularly polarizing plate 11 of this embodiment, as the bonding layer 36 for bonding the λ/4 retardation layer 38 to another layer, one having a low moisture permeability is used. Thereby, it is considered that the bonding layer 36 functions as a barrier layer for moisture, etc., and the movement of moisture between the λ/4 retardation layer 38 and other layers such as the linear polarizing layer 33 laminated via the bonding layer 36 can be suppressed. The decrease in optical characteristics after the test was suppressed.

In addition, the linearly polarizing layer 33 included in the circularly polarizing plate 11 contains a cured product of a polymerizable liquid crystal compound and a dichroic dye. Therefore, compared with a linearly polarizing layer formed by stretching a polyvinyl alcohol-based resin film, The shrinkage in the damp heat test is small, so the dimensional change is small. In this respect, it is also considered that it is easy to suppress the decrease in optical characteristics after the wet heat test.

The circularly polarizing plate 11 of this embodiment can be used in display devices such as organic EL display devices. As described above, the circular polarizing plate 11 has good damp and heat durability, and therefore can be applied to an on-vehicle display device that is easily exposed to a high temperature and humidity environment for a long time. Examples of display devices for in-vehicle use include car navigation systems, instrument panels, door mirrors, and back mirrors.

(Modification of circular polarizing plate) The circularly polarizing plate of this embodiment may have the structure shown in FIGS. 2 to 4. 2 to 4 are schematic cross-sectional views schematically showing another example of the circularly polarizing plate of the present embodiment.

The circular polarizing plate 12 shown in FIG. 2 has a base layer 32 on the side of the linear polarizing layer 33 of the circular polarizing plate 11 shown in FIG. 1 opposite to the side of the bonding layer 36. Therefore, as shown in FIG. 2, the circular polarizing plate 12 has a base layer 32, a linear polarizing layer 33, a bonding layer 36, and a λ/4 retardation layer 38 in this order. An alignment layer may also be provided between the base layer 32 and the linear polarizing layer 33. As described later, the base layer 32 may be used to form the linear polarizing layer 33.

The circular polarizing plate 13 shown in FIG. 3 has an overcoat layer 34 between the linear polarizing layer 33 and the bonding layer 36 of the circular polarizing plate 12 shown in FIG. 2. Therefore, the circularly polarizing plate 13 has a base layer 32, a linearly polarizing layer 33, an overcoat layer 34, a bonding layer 36, and a λ/4 retardation layer 38 in this order. In the circular polarizing plate 13 shown in FIG. 3, the case where the base material layer 32 is provided is taken as an example for description, but it may be one that does not have the base material layer 32.

The circular polarizing plate 14 shown in FIG. 4 has a hard coat layer 31 on the side opposite to the linear polarizing layer 33 of the base layer 32 of the circular polarizing plate 13 shown in FIG. 3. Therefore, the circular polarizing plate 14 has a hard coat layer 31, a base layer 32, a linear polarizing layer 33, an overcoat layer 34, a bonding layer 36, and a λ/4 retardation layer 38 in this order. In the circular polarizing plate 14 shown in FIG. 4, the case where the overcoat layer 34 is provided is taken as an example for description, but it may be one without the overcoat layer 34.

The circular polarizing plate shown in FIGS. 1 to 4 may have an alignment on the side of the λ/4 retardation layer 38 opposite to the side of the bonding layer 36, or the side of the bonding layer 36 of the λ/4 retardation layer 38 The layer may have an alignment layer on the side of the bonding layer 36 of the linear polarizing layer 33. In addition, the circular polarizing plate that does not have the base layer 32 may have an alignment layer on the side of the linear polarizing layer 33 opposite to the side of the bonding layer 36.

The circular polarizing plate shown in FIGS. 1 to 4 may have a λ/2 retardation layer or a positive C-layer between the linear polarizing layer 33 and the bonding layer 36. In this case, the λ/2 retardation layer or the positive C layer is preferably bonded to the linear polarizing layer 33 via another bonding layer different from the bonding layer 36. The other bonding layer may be an adhesive layer formed using an adhesive composition, or an adhesive layer formed using an adhesive composition. The other bonding layer may be one that does not have the moisture permeability within the range that the bonding layer 36 has, but it is preferably one that has the moisture permeability. In addition, the circularly polarizing plate shown in FIGS. 1 to 4 may have a positive C layer via another bonding layer on the side of the λ/4 retardation layer 38 opposite to the bonding layer 36 side. That is, when the circular polarizing plate shown in FIGS. 1 to 4 has a positive C layer, the positive C layer may be provided between the linear polarizing layer 33 and the bonding layer 36, or may be provided on the λ/4 retardation layer 38 is the side opposite to the side of the bonding layer 36. In the case where the circular polarizing plate has a positive C layer, the λ/4 retardation layer 38 preferably has reverse wavelength dispersion. The λ/2 retardation layer or the positive C layer may contain a cured product of a polymerizable liquid crystal compound, or may be a resin film.

In the case where the circular polarizer includes the λ/4 retardation layer 38 and the positive C layer, the angle formed by the absorption axis of the linear polarizing layer 33 and the slow axis of the λ/4 retardation layer can be set to 45°±10°. It can also be set to 45°±5°. In the case where the circularly polarizing plate has a λ/2 retardation layer and a λ/4 retardation layer 38 in this order from the side close to the linear polarizing layer 33, the absorption axis of the linear polarizing layer 33 is slower than the λ/2 retardation layer. The angle formed by the shaft can be set to 15°±10° or 15°±5°. At this time, the angle formed by the absorption axis of the linear polarizing layer 33 and the slow axis of the λ/4 retardation layer 38 may be 75°±10°, or 75°±5°.

＜Circular polarizing plate with glass plate＞ FIG. 5 is a schematic cross-sectional view schematically showing an example of the circularly polarizing plate 21 with a glass plate according to this embodiment. The circular polarizing plate 21 with glass plates has glass plates 41 on both sides of the circular polarizing plate 13 shown in FIG. 3. In the circular polarizing plate 21 with a glass plate shown in FIG. 5, a case where the circular polarizing plate 13 has glass plates 41 on both sides is shown as an example, but it may also be one having glass plates 41 on one side of the circular polarizing plate 13 . In this case, the other surface of the circular polarizing plate 13 may be exposed, and a resin plate or the like may be bonded. The glass plate 41 can be bonded to the circular polarizing plate via the bonding layer 42 for glass plates. The bonding layer 42 for a glass plate is an adhesive layer formed using an adhesive composition, or an adhesive layer formed using an adhesive composition.

The glass plate 41 provided on the visible side of the circular polarizing plate 12 may be one included in a front surface plate or a touch panel arranged on the frontmost surface of the display device. The glass plate 41 disposed on the side of the image display element of the circular polarizer may be one included in the touch panel or the image display element.

As described above, the circular polarizing plate 21 with a glass plate includes a circular polarizing plate having good damp-heat durability, and therefore can be applied to an on-vehicle display device that is easily exposed to a high temperature and high humidity environment for a long time.

Hereinafter, each layer of the circular polarizing plate and the circular polarizing plate with glass plate will be described. (Laminated layer) The bonding layer 36 is a layer for bonding the λ/4 retardation layer 38 to other layers. It can be directly provided on the λ/4 retardation layer 38, or it may be provided in the presence of no other bonding layer. On the layer on the λ/4 retardation layer 38 (base material layer for forming the alignment layer, the λ/4 retardation layer, etc.). The bonding layer 36 is an adhesive layer formed using an adhesive composition or an adhesive layer formed using an adhesive composition.

As described above, the moisture permeability of the bonding layer 36 at a temperature of 40° C. and a humidity of 90% RH is 100 g/(m ² ·24 hr) or less. The moisture permeability of the bonding layer 36 may be 80 g/(m ² ·24 hr) or less, 60 g/(m ² ·24 hr) or less, or 50 g/(m ² ·24 hr) ) Or less, may be 40 g/(m ² ·24 hr) or less, and may be 5 g/(m ² ·24 hr) or more.

The moisture permeability of the bonding layer 36 can be adjusted, for example, by adjusting the composition and thickness of the adhesive composition or the adhesive composition constituting the bonding layer 36.

When the bonding layer 36 is an adhesive layer, the adhesive composition for forming the adhesive layer is not particularly limited as long as it satisfies the moisture permeability. As the adhesive composition, for example, as long as it contains rubber polymer, (meth)acrylic polymer, urethane polymer, polyester polymer, silicone polymer, polyvinyl ether polymer Polyvinyl alcohol-based polymer, polyolefin-based polymer, vinyl alkyl ether-based polymer, polyvinylpyrrolidone-based polymer, poly(meth)acrylamide-based polymer, cellulose-based polymer It is sufficient if the polymer is the main component. In this specification, the main component means a component containing 50% by mass or more in the total solid content of the adhesive composition. The adhesive composition can be an active energy ray hardening type or a heat hardening type. As the adhesive composition, a rubber-based polymer is preferred. In addition, the "(meth)acrylic acid" means "at least one of acrylic acid and methacrylic acid". The same applies to expressions such as "(meth)acrylate".

Examples of rubber polymers include natural rubber; polyisobutylene rubber (PIB), isoprene rubber (IR), isobutylene-isoprene rubber (IIR), N-butene-isobutylene copolymer rubber, butadiene rubber (BR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (nitrile butadiene) Rubber (nitrile-butadiene rubber, NBR), styrene-butadiene rubber (styrene-butadiene rubber, SBR), styrene-isoprene rubber (SIR), styrene-isoprene rubber Styrene-isoprene-styrene block copolymer rubber (styrene-isoprene-butadiene-styrene (styrene-isoprene-butadiene-styrene, SIBS)), styrene- Styrene-ethylene-butylene-styrene block copolymer rubber (SEBS), styrene-ethylene-propylene-styrene block copolymer rubber (styrene-ethylene-propylene-styrene block copolymer rubber (SEPS), styrene-butadiene-styrene block copolymer rubber (SBS), styrene-ethylene-propylene block copolymer rubber (styrene-ethylene-propylene block copolymer rubber, SEP) and other synthetic rubbers. The rubber-based polymer is preferably polyisobutylene rubber (PIB), isobutylene-isoprene rubber (IIR), n-butylene-isobutylene copolymer rubber, and more preferably polyisobutylene rubber (PIB).

As the (meth)acrylic polymer, butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethyl (meth)acrylate can be preferably used. One or two or more of (meth)acrylates such as hexyl ester are polymers or copolymers as monomers. In the base polymer, it is preferable to copolymerize a polar monomer. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, (meth)acrylic acid N, N -Monomers such as dimethylaminoethyl and glycidyl (meth)acrylate having a carboxyl group, a hydroxyl group, an amide group, an amino group, and an epoxy group.

The so-called active energy ray curable adhesive composition means that it has the property of being cured by irradiation of active energy rays such as ultraviolet rays or electron rays, and has adhesiveness even before the active energy rays are irradiated, so that it can bond with the film. Adhesive composition that can adjust the properties of adhesion by curing by the irradiation of active energy rays. The active energy ray curable adhesive composition is preferably an ultraviolet curable adhesive composition. The active energy ray curable adhesive composition contains an active energy ray polymerizable compound in addition to a base polymer and a crosslinking agent. Furthermore, if necessary, a photopolymerization initiator, photosensitizer, etc. may be contained.

In addition to polymers, the adhesive composition may also contain solvents; adhesion imparting agents, softeners, fillers (metal powder or other inorganic powders, etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers , Preservatives, photopolymerization initiators and other additives. In the case of using an active energy ray-curable adhesive composition, by irradiating the formed adhesive layer with active energy rays, a cured product having a desired degree of curing can be obtained.

The adhesive layer can be formed by coating the organic solvent dilution of the adhesive composition on the substrate and drying it.

When the bonding layer 36 is an adhesive layer, the adhesive composition for forming the adhesive layer is not particularly limited as long as it satisfies the moisture permeability. Examples of the adhesive composition include: water-based adhesives, active energy ray-curing adhesives, natural rubber adhesives, α-olefin-based adhesives, urethane resin-based adhesives, and ethylene-vinyl acetate resins. Emulsion adhesive, ethylene-vinyl acetate resin hot melt adhesive, epoxy resin adhesive, vinyl chloride resin solvent adhesive, chloroprene rubber adhesive, cyanoacrylate adhesive, silicone Adhesives, styrene-butadiene rubber solvent-based adhesives, nitrile rubber-based adhesives, nitrocellulose-based adhesives, reactive hot melt adhesives, phenol resin-based adhesives, modified silicone-based adhesives, Polyester hot melt adhesive, polyamide resin hot melt adhesive, polyimide resin hot melt adhesive, polyurethane resin hot melt adhesive, polyolefin resin hot melt adhesive, polyvinyl acetate resin Solvent based adhesive, polystyrene resin solvent based adhesive, polyvinyl alcohol based adhesive, polyvinylpyrrolidone resin based adhesive, polyvinyl butyral based adhesive, polybenzimidazole based adhesive, polymethyl Acrylic resin solvent-based adhesives, melamine resin-based adhesives, urea resin-based adhesives, resorcinol-based adhesives, etc. Such an adhesive can be used individually by 1 type or in mixture of 2 or more types.

Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution, an aqueous two-component urethane-based emulsion adhesive, and the like. The active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays. Examples include those containing polymerizable compounds and photopolymerizable initiators, those containing photoreactive resins, and those containing adhesives. Resins and photoreactive crosslinkers, etc. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth)acrylic monomers, and photocurable urethane monomers, or sources. Oligomers from these monomers, etc. Examples of the photopolymerization initiator include those containing active species such as neutral radicals, anionic radicals, and cationic radicals by irradiating active energy rays such as ultraviolet rays.

The thickness of the bonding layer is not particularly limited. When the bonding layer is an adhesive layer, it is preferably 5 μm or more, may be 15 μm or more, may be 20 μm or more, or may be 25 μm or more, and Generally, it is 200 μm or less, but may be 100 μm or less, or may be 50 μm or less. When the bonding layer is an adhesive layer, the thickness of the bonding layer is preferably 0.01 μm or more, may be 0.05 μm or more, or may be 0.5 μm or more, and is preferably 5 μm or less, and may be 3 μm or less , It can also be 2 μm or less.

(Linear polarizing layer) The linearly polarizing layer 33 has a function of selectively transmitting linearly polarized light in a certain direction from non-polarized light such as natural light. As described above, the linear polarizing layer 33 contains the cured product of the polymerizable liquid crystal compound and the dichroic dye, and the dichroic dye is dispersed and aligned in the cured product of the polymerizable liquid crystal compound. Compared with a linear polarizing layer in which a dichroic dye such as iodine is adsorbed and aligned on a polyvinyl alcohol-based resin, the linear polarizing layer 33 has a small shrinkage in the wet heat test, and therefore has a small dimensional change. Therefore, it can be applied to a circular polarizing plate used in an environment requiring heat and humidity durability.

The polymerizable liquid crystal compound is a compound having a polymerizable reactive group and exhibiting liquid crystallinity. The polymerizable reactive group is a group that participates in the polymerization reaction, and is preferably a photopolymerizable reactive group. The photopolymerizable reactive group refers to a group that can participate in a polymerization reaction by a living radical or acid generated from a photopolymerization initiator. Examples of photopolymerizable functional groups include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloxy, and oxa Cyclopropanyl, oxetanyl, etc. Among them, propyleneoxy group, methacryloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and propyleneoxy group is more preferable. The type of the polymerizable liquid crystal compound is not particularly limited, and rod-shaped liquid crystal compounds, disc-shaped liquid crystal compounds, and mixtures thereof can be used. The liquid crystallinity of the polymerizable liquid crystal compound may be thermotropic liquid crystal or lyotropic liquid crystal, and may be nematic liquid crystal or smectic liquid crystal as a phase sequence structure.

The dichroic dye refers to a dye having a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction of the molecule.

The dichroic dye is preferably one having an absorption maximum wavelength (λMAX) in the range of 300 nm to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes. Among them, azo dyes are preferred. Examples of azo dyes include monoazo dyes, disazo dyes, trisazo dyes, tetrasazo dyes, and stilbene azo dyes, and bisazo dyes and trisazo dyes are preferred. The dichroic dye may be alone or in combination of two or more, preferably three or more in combination. In particular, it is more preferable to combine three or more azo compounds. A part of the dichroic dye may have a reactive group, and may also have liquid crystallinity.

The linear polarizing layer 33 can be formed by, for example, coating a polarizing layer forming composition containing a polymerizable liquid crystal compound and a dichroic dye on the alignment layer formed on the base layer 32, and polymerizing the polymerizable liquid crystal compound to harden it. And formed. Alternatively, the composition for forming a polarizing layer may be coated on the base layer 32 to form a coating film, and the coating film may be stretched together with the base layer 32 to form the linear polarizing layer 33. As shown in FIGS. 2 to 4, the base material layer 32 for forming the linear polarizing layer 33 may also be included in the circular polarizing plate.

As a composition for forming a polarizing layer containing a polymerizable liquid crystal compound and a dichroic dye, and a method for producing a linear polarizing layer using the composition, Japanese Patent Laid-Open No. 2013-37353 and Japanese Patent Laid-Open 2013- It is described in No. 33249, Japanese Patent Laid-Open No. 2017-83843, etc. In addition to the polymerizable liquid crystal compound and the dichroic dye, the polarizing layer forming composition may further contain additives such as a solvent, a polymerization initiator, a crosslinking agent, a leveling agent, an antioxidant, a plasticizer, and a sensitizer. Only one kind of these components may be used, or two or more kinds may be used in combination.

The polymerization initiator that may be contained in the composition for forming a polarizing layer is a compound that can initiate a polymerization reaction of a polymerizable liquid crystal compound. In terms of being capable of initiating a polymerization reaction under lower temperature conditions, a photopolymerizable initiator is preferred . Specifically, photopolymerization initiators that can generate active radicals or acids by the action of light can be cited, and among them, photopolymerization initiators that can generate free radicals by the action of light are preferred. The content of the polymerization initiator is preferably 1 part by mass to 10 parts by mass, more preferably 3 parts by mass to 8 parts by mass relative to 100 parts by mass of the total amount of the polymerizable liquid crystal compound. If it is within this range, the reaction of the polymerizable group proceeds sufficiently, and it is easy to stabilize the alignment state of the liquid crystal compound.

The thickness of the linear polarizing layer is not particularly limited, but is preferably 20 μm or less, more preferably 10 μm or less, and still more preferably 5 μm or less.

(Substrate layer) The base layer 32 that the circular polarizing plate may have can function as a protective layer of the linear polarizing layer 33. When forming the linear polarizing layer 33, the base layer 32 may be used to coat the composition for forming a polarizing layer.

The base material layer 32 is preferably a film containing a resin material. As the resin material, for example, resin materials excellent in transparency, mechanical strength, thermal stability, stretchability, etc. can be used. Specifically, examples include: polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene-based polymers; polyethylene terephthalate, polyethylene naphthalate, and other polyolefin resins; Ester resins; (meth)acrylic resins such as (meth)acrylic acid and polymethyl (meth)acrylate; cellulose ester resins such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate ; Vinyl alcohol-based resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate-based resins; polystyrene-based resins; polyarylate-based resins; polyether-based resins; polyether-based resins; polyamide-based resins; Polyimide-based resins; polyetherketone-based resins; polyphenylene sulfide-based resins; polyphenylene oxide-based resins, and mixtures and copolymers thereof. Among these resins, it is preferable to use any one or a mixture of cyclic polyolefin resins, polyester resins, cellulose ester resins, and (meth)acrylic resins.

The base layer 32 may be a single layer mixed with one or more than two resin materials, or may have a multilayer structure of two or more layers. In the case of a multilayer structure, the resins forming each layer may be the same or different from each other. When the base material layer 32 is a film containing a resin material, arbitrary additives can be added to the base material layer 32. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and coloring agents.

The thickness of the base layer 32 is not particularly limited. Generally, in terms of workability such as strength and handling properties, it is preferably 5 μm or more, may be 10 μm or more, or 15 μm or more, and is usually 300 μm or less, 200 μm or less, or 100 μm or less.

(Λ/4 retardation layer) The λ/4 retardation layer 38 has a function of substantially imparting a phase difference of λ/4 to incident light, and the incident light is usually light in the visible light region. As described above, the λ/4 retardation layer 38 contains a cured product of a polymerizable liquid crystal compound. As the polymerizable liquid crystal compound, for example, the compounds described above can be used. The polymerizable liquid crystal compound forming the polarizing layer and the polymerizable liquid crystal compound forming the λ/4 retardation layer may be the same or different.

The λ/4 retardation layer 38 can be formed by, for example, coating a composition for forming a retardation layer containing a polymerizable liquid crystal compound on a substrate layer for a retardation layer, and polymerizing and curing the polymerizable liquid crystal compound. The base material layer for a retardation layer for forming the λ/4 retardation layer 38 may be contained in a circular polarizing plate. As the substrate layer for the retardation layer, for example, those described in the above-mentioned substrate layer can be used.

The thickness of the λ/4 retardation layer 38 is not particularly limited, and is preferably 0.1 μm or more, may be 0.5 μm or more, or may be 1 μm or more, and is usually 50 μm or less, may be 30 μm or less, or 20 μm or less, and preferably 10 μm or less from the viewpoint of thickness reduction.

(Outer coating) The outer coating 34 (Figures 3 to 5) that the circular polarizing plate can have can protect the linear polarizing layer 33, inhibit the transfer of dichroic pigments in the linear polarizing layer 33, and impart barrier properties to oxygen or moisture. Set up. The outer coating 34 can be provided on both sides of the linear polarizing layer 33, or can be provided on a single side. In the case where the substrate layer 32 is provided on the side of the linearly polarizing layer 33 opposite to the bonding layer 36, the overcoat layer 34 can be directly provided on the side of the bonding layer 36 of the linearly polarizing layer 33, for example, by The linear polarizing layer 33 is formed by coating a material (composition) for forming the overcoat layer 34.

The overcoat layer 34 is preferably one that is excellent in solvent resistance, transparency, mechanical strength, thermal stability, shielding properties, and isotropy. The outer coating 34 provided on one surface of the linear polarizing layer 33 may be one layer or two or more layers. When the overcoat layer 34 is two or more layers, the materials constituting each layer may be the same or different from each other. In addition, when the overcoat layers 34 are provided on both sides of the linear polarizing layer 33, the overcoat layers 34 may be formed of the same material or different materials. As a material constituting the overcoat layer 34, for example, a photocurable resin or a water-soluble polymer can be cited.

Examples of the photocurable resin include (meth)acrylic resins, urethane resins, (meth)acrylate urethane resins, epoxy resins, and silicone resins. Examples of water-soluble polymers include: poly(meth)acrylamide-based polymers; polyvinyl alcohol and ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, (meth)acrylic acid or its anhydride- Vinyl alcohol polymers such as vinyl alcohol copolymers; carboxyvinyl polymers; polyvinylpyrrolidone; starches; sodium alginate; polyethylene oxide polymers, etc.

The thickness of the overcoat layer 34 is not particularly limited, and is preferably 20 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, may be 5 μm or less, and may be 0.05 μm or more, or may be 0.5 μm the above.

(Hard coating) The hard coat layer 31 (FIG. 4) that the circular polarizing plate may have is provided for the purpose of improving the hardness or scratch resistance of the base layer 32. The hard coat layer 31 may be provided on both sides of the base layer 32, and is preferably provided on the side of the base layer 32 opposite to the side of the linear polarizing layer 33. The hard coat layer 31 can be formed, for example, by coating a material (composition) for forming the hard coat layer 31 on the base layer 32.

The hard coat layer is, for example, a cured layer of ultraviolet curable resin. Examples of ultraviolet curable resins include monofunctional (meth)acrylic resins, polyfunctional (meth)acrylic resins, and polyfunctional (meth)acrylic resins having a dendrimer structure. Meth) acrylic resin; silicone resin; polyester resin; urethane resin; amide resin; epoxy resin, etc. In order to increase strength, the hard coat layer may also contain additives. The additives are not limited, and examples include inorganic fine particles, organic fine particles, or a mixture of these.

(Orientation layer) The alignment layer has an alignment restricting force for aligning the liquid crystal of the polymerizable liquid crystal compound in a desired direction. As described above, the circularly polarizing plate may have an alignment layer on the side of the linear polarizing layer 33 opposite to the side of the bonding layer 36, or on the side of the λ/4 retardation layer 38 opposite to the side of the bonding layer 36. The side or the side of the bonding layer 36 of the λ/4 retardation layer 38 has an alignment layer. In the circularly polarizing plate each having the alignment layer for the linear polarizing layer 33 and the alignment layer for the λ/4 retardation layer, the layer structure can be, for example, any of the following [a] to [d]: [a] Alignment layer, linear polarizing layer, bonding layer, λ/4 retardation layer, alignment layer [b] Linear polarizing layer, alignment layer, bonding layer, λ/4 retardation layer, alignment layer [c] Alignment layer, linear polarizing layer, bonding layer, alignment layer, λ/4 retardation layer [d] Linear polarizing layer, alignment layer, bonding layer, alignment layer, λ/4 retardation layer.

Examples of the alignment layer include an alignment polymer layer containing an alignment polymer, a photoalignment polymer layer containing a photoalignment polymer, and a groove having a concave-convex pattern or a plurality of grooves (grooves) on the surface of the layer. Slot alignment layer. The thickness of the alignment layer is usually 10 nm to 500 nm, preferably 10 nm to 200 nm.

The aligning polymer layer can be formed by applying a composition obtained by dissolving an aligning polymer in a solvent on a substrate layer or a substrate layer for a phase layer, removing the solvent, and performing a rubbing treatment as necessary. In this case, in the alignment polymer layer containing the alignment polymer, the alignment restriction force can be arbitrarily adjusted according to the surface state of the alignment polymer or friction conditions.

The photoalignment polymer layer can be formed by applying a composition containing a polymer or monomer having a photoreactive group and a solvent to the substrate layer or the substrate layer for the phase layer, and irradiating it with polarized light. In this case, in the photoalignment polymer layer, the alignment restriction force can be arbitrarily adjusted according to the polarized light irradiation conditions for the photoalignment polymer.

The groove alignment layer can be formed, for example, by a method of forming a concave-convex pattern by exposure, development, etc., through an exposure mask having pattern-shaped slits on the surface of the photosensitive polyimide film; A method of forming an uncured layer of active energy ray curable resin on a plate-shaped master disk, transferring the layer to the base layer or phase layer and curing it; in the base layer or phase layer The layer forms an uncured layer of active energy ray-curable resin, and a method of forming and curing the unevenness by pressing the roller-shaped master plate having unevenness on the layer.

(Lamination layer for glass plate) The bonding layer 42 for a glass plate is a layer for bonding a circular polarizing plate and the glass plate 41 together. The bonding layer 42 for a glass plate is an adhesive layer formed using an adhesive composition, or an adhesive layer formed using an adhesive composition. As the material contained in the adhesive composition or the adhesive composition, known materials can be used, for example, the materials exemplified in the adhesive composition or the adhesive composition used in the bonding layer.

The thickness of the bonding layer for a glass plate is also not specifically limited, For example, it can be 10 micrometers or more and 200 micrometers or less.

(glass plate) The glass plate 41 can use a well-known glass plate. The glass plate 41 may be, for example, a front surface plate, a touch panel, and an image display element disposed on the front surface of the display device.

The thickness of the glass plate 41 is not specifically limited, For example, it can be 30 micrometers or more and 2 mm or less. [Example]

Hereinafter, examples and comparative examples are shown to explain the present invention more specifically, but the present invention is not limited by these examples. As long as there is no special description, the blending amounts indicated by "%" and "parts" in the examples and comparative examples are mass% and mass parts.

The evaluation method is as follows. [Determination of moisture permeability] The moisture permeability of the adhesive layer used in the examples was measured in the following procedure. On the adhesive layer side of the adhesive sheet prepared in the following adhesive sheet preparation item, a triacetyl cellulose (TAC) film (KC2UA, Konica Minolta) (stock) is attached Manufacturing, thickness 25 μm). After that, the release film was peeled off to obtain a sample for measurement. Using the obtained sample for measurement, it was measured at a measurement temperature of 40°C, a measurement humidity of 90%RH, and a measurement time of 24 hours by the moisture permeability test method based on the Japanese Industrial Standards (JIS) Z 0208 (cup method) Moisture permeability (water vapor transmission rate). Use a constant temperature and humidity bath for measurement. The results are shown in Table 1. Furthermore, the moisture permeability of the TAC film is sufficiently large compared to the moisture permeability of the adhesive layer, and therefore the moisture permeability measured using the measurement sample can be regarded as the moisture permeability of the adhesive layer.

In addition, for the adhesive layer used in the comparative example, the adhesive layer was bonded to the TAC film, and the moisture permeability was measured in the same procedure as described above. The results are shown in Table 1.

[Damp heat test] Using the circularly polarizing plates with glass plates in which glass plates are provided on both sides of the circularly polarizing plates obtained in the Examples and Comparative Examples, reflectance and retardation (R0) were measured, and the appearance was evaluated. Next, after performing a damp heat test in which the circularly polarizing plate with a glass plate was stored in a damp heat environment with a temperature of 85° C. and a humidity of 85% RH for 150 hours, the reflectance and the retardation were measured, and the appearance was evaluated. The change in reflectance before and after the damp heat test (Δ reflectance [%]) and the change in delay before and after the damp heat test (ΔR0) were calculated, and the change in appearance before and after the damp heat test was evaluated. In addition, the circular polarizer with a glass plate after the damp heat test was evaluated for the reflection hue observed from the oblique direction. The measurement of reflectance, retardation, and reflection hue observed from an oblique direction was performed in the following procedure. In addition, the change in appearance and the reflection hue observed from the oblique direction were evaluated as follows.

(1) Measurement of reflectivity The circular polarizing plate with glass plate obtained in the Examples and Comparative Examples was placed on the reflecting plate (aluminum plate, 97% reflectivity) so that the linear polarizing layer side became the visible side with respect to the λ/4 retardation layer , Using a spectrophotometer (CM-2600d, manufactured by Konica Minolta), the reflectance [%] was measured under the conditions of Specular Component Included (SCI) mode and D65 standard light. The change in reflectance before and after the damp heat test (Δ reflectance [%]) is calculated based on the following formula: ΔReflectance [%] = (Reflectance after damp heat test [%])-(Reflectance before damp heat test [%]).

(2) Determination of delay (R0) For the circular polarizers with glass plates obtained in the Examples and Comparative Examples, a phase difference meter (KOBRA (registered trademark)-WPR, manufactured by Oji Measuring Instruments Co., Ltd.) based on the principle of the parallel Nicol rotation method was used. At a temperature of 23°C, the in-plane retardation at a wavelength of 550 nm was measured. The delay change (ΔR0[nm]) before and after the damp heat test is calculated based on the following formula: ΔR0[nm]=(Retardation after damp heat test [nm])-(Retardation before damp heat test [nm]).

(3) Appearance evaluation The circular polarizing plate with glass plate obtained in the Examples and Comparative Examples was placed on the reflecting plate (aluminum plate, 97% reflectivity) so that the linear polarizing layer side became the visible side with respect to the λ/4 retardation layer , To evaluate the presence or absence of redness when viewed from the side of the linearly polarizing layer. The case where the red change was not recognized was evaluated as A, and the case where the red change was recognized was evaluated as B.

(4) Evaluation of reflection hue observed from an oblique direction The circular polarizer with glass plate obtained in the examples and comparative examples was placed on the circular polarizing plate with glass plate obtained in the examples and comparative examples so that the linear polarizing layer side became the visible side with respect to the λ/4 retardation layer On the reflector (aluminum plate, 97% reflectivity). For this circular polarizer with a glass plate, a display measurement system (DMS-803, Instrument Systems (Instrument Systems)) was used to measure the color coordinate La*b* from a direction with an omnidirectional angle of 50°. From the color coordinate of the largest a* and the color coordinate of the smallest a*, ΔE is calculated based on the following formula. In the formula, the maximum color coordinate of a* is (a* ¹ , b* ¹ ), and the minimum color coordinate of a* is (a* ² , b* ² ). ΔE=(｜a* ¹ -a* ² ｜ ² +｜b* ¹ -b* ² ｜ ² ) ^0.5 The case where ΔE is 10 or less is evaluated as A, and the case where ΔE exceeds 10 and is 21 or less is evaluated as B , The case where ΔE exceeds 21 is evaluated as C.

The materials used in the circular polarizing plate with glass plate obtained in each Example and Comparative Example were prepared in the following order.

[Preparation of adhesive sheet] An adhesive sheet (x) and an adhesive sheet (y) having an adhesive layer as an adhesive layer are prepared. (1) Adhesive sheet (x) 100 parts of polyisobutylene (PIB) (OPPANOL B80, manufactured by BASF Corporation, Mw: about 750,000) as a rubber-based polymer, tricyclodecane dimethanol diacrylate (NK ester A) -DCP, manufactured by Shinnakamura Chemical Industry Co., Ltd., difunctional acrylate, molecular weight 304) 10 parts, benzophenone (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator 0.5 parts, as an adhesive imparting agent 5 parts of fully hydrogenated terpene phenol (manufactured by Yasuhara Chemical (stock)). Toluene was added to the mixture so that the total solid content concentration was 15% to obtain an adhesive composition.

The adhesive composition obtained above was applied to the release film (polyethylene terephthalate film with release treatment, thickness 38 μm) using an applicator so that the thickness after drying was 25 μm The mold-releasing treatment surface was dried at a temperature of 80°C for 3 minutes, and UV-A was irradiated with a light amount of 1000 mJ to obtain an adhesive sheet (x) with an adhesive layer (X).

(2) Adhesive sheet (y) In addition to using trimethylolpropane triacrylate (NK ester A-TMPT, manufactured by Shinnakamura Chemical Industry Co., Ltd., trifunctional acrylate, molecular weight 296) instead of tricyclodecane dimethanol diacrylate, it will be completely hydrogenated The blending amount of terpene phenol was set to other than 10 parts, and the adhesive composition was obtained in the same manner as the preparation of the adhesive sheet (x). Except for using the adhesive composition obtained here, an adhesive sheet (y) provided with an adhesive layer (Y) was obtained in the same manner as the adhesive sheet (x).

[Preparation of composition for formation of alignment layer] A solution obtained by dissolving a polymer having a photoreactive group represented by the following structural formula in cyclopentanone at a concentration of 5% was prepared as an alignment layer forming composition (1).

[化1]

[Preparation of composition for forming polarizing layer] The compound (1-1) and the compound (1-2) represented by the following structures are used as the polymerizable liquid crystal compound. Compound (1-1) and Compound (1-2) were obtained by Lub et al. (Lub et al.) "Recl. Trav. Chim. Pays-Bas", 115, 321-328 ( The method described in 1996) was synthesized. ･Compound (1-1)

･化合物（1-2）[化2]

･Compound (1-2)

[化3]

The compound (2-1a), the compound (2-1b), and the compound (2-3a) represented by the following structures are used as the dichroic dye. ･Compound (2-1a)

･化合物（2-1b）[化4]

･Compound (2-1b)

･化合物（2-3a）[化5]

･Compound (2-3a)

[化6]

The composition for forming a polarizer was prepared by combining 75 parts of compound (1-1), 25 parts of compound (1-2), and the formula (2-1a) and formula (2- 1b), 2.5 parts each of the azo dye represented by the formula (2-3a), 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butyl as a polymerization initiator Mixing of 6 parts of alkane-1-one (Irgacure 369, manufactured by BASF) and 1.2 parts of polyacrylate compound (BYK-361N, manufactured by BYK) as a leveling agent To 400 parts of toluene as a solvent, the resulting mixture was stirred at 80°C for 1 hour.

[Preparation of λ/4 retardation layer] (Preparation of composition for forming retardation layer) The composition for forming a retardation layer for forming a λ/4 retardation layer is prepared by mixing the components shown below, and stirring the resulting mixture at 80°C for 1 hour.

･Compounds represented by the following structural formula: 80 parts

･由下述結構式所表示的化合物：20份[化7]

･The compound represented by the following structural formula: 20 parts

･聚合起始劑（豔佳固（Irgacure）369，巴斯夫（BASF）公司製造）：6份 ･調平劑（BYK-361N，聚丙烯酸酯化合物，畢克（BYK）公司製造）：0.1份 ･溶劑（環戊酮）：400份[化8]

･Polymerization initiator (Irgacure 369, manufactured by BASF): 6 parts ･Leveling agent (BYK-361N, polyacrylate compound, manufactured by BYK): 0.1 part ･ Solvent (cyclopentanone): 400 parts

(Fabrication of λ/4 retardation layer) On a polyethylene terephthalate (PET) film (thickness 100 μm) as a substrate, the alignment prepared above was coated by bar coating The layer formation composition (1) was heated and dried in a drying oven at a temperature of 80°C for 1 minute. The obtained coating film was subjected to a polarization UV irradiation treatment to form an alignment layer. The polarization UV treatment was performed using a UV irradiation device (SPOT CURE SP-7, manufactured by Ushio Electric Co., Ltd.) under the condition that the cumulative light intensity measured at a wavelength of 365 nm was 100 mJ/cm ² . In addition, it is performed so that the polarization direction of the polarized light UV is 45° with respect to the absorption axis of the polarizer.

On the alignment layer formed above, the composition for forming the retardation layer prepared above was coated by a bar coating method, heated and dried in a drying oven at a temperature of 120° C. for 1 minute, and then cooled to room temperature. Using the UV irradiation device, the coating film obtained was irradiated with ultraviolet rays in a manner that the cumulative light amount was 1000 mJ/cm ² (365 nm reference) to form a λ/4 retardation layer with a thickness of 2.0 μm, and a λ with a PET film was obtained. /4 retardation layer. The λ/4 retardation layer exhibits reverse wavelength dispersion.

[Preparation for the positive C floor] (Preparation of composition for formation of alignment layer) 2-butoxyethanol was added to SUNEVER SE-610 (manufactured by Nissan Chemical Co., Ltd.) to prepare an alignment layer forming composition (2).

(Preparation of composition for forming retardation layer) The composition for forming a retardation layer for forming the positive C layer is prepared by mixing the components shown below, stirring the resulting mixture at 80°C for 1 hour, and cooling to room temperature. ･LC242 (BASF, polymerizable liquid crystal compound): 20.3 parts ･Polymerization initiator (Irgacure 907, manufactured by BASF): 0.5 part ･Leveling agent (BYK-361N, polyacrylate compound, manufactured by BYK): 0.1 part ･Solvent (propylene glycol 1-monomethyl ether 2-acetate): 400 parts

(Production of positive C layer) A non-stretching cycloolefin polymer film (ZF-14 manufactured by Zeon, thickness 23 μm) was prepared as a substrate. The surface of the film was corona treated once using a corona treatment device at an output of 0.3 kW and a treatment speed of 3 m/min. On the surface subjected to the corona treatment, the alignment layer forming composition (2) was applied using a bar coater. The coating film was dried at 90°C for 1 minute to form a vertical alignment layer. The thickness of the resulting vertical alignment layer was 34 nm.

The composition for forming a retardation layer was coated on the vertical alignment layer using a bar coater. The coating film was dried at 90°C for 1 minute. A high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Usio Electric Co., Ltd.) was used to irradiate ultraviolet light to polymerize the polymerizable liquid crystal compound. Ultraviolet rays are irradiated in a nitrogen atmosphere and irradiated so that the cumulative light intensity at a wavelength of 365 nm is 1000 mJ/cm ² . The film thickness of the obtained retardation layer was 450 nm. In addition, the retardation value of the obtained retardation layer was measured at a wavelength of 550 nm. As a result, Re(550)=1 nm and Rth(550)=-70 nm. That is, the relationship of the three-dimensional refractive index of the obtained retardation layer is nx≒ny<nz, and it has optical characteristics as a positive C layer.

[Preparation of λ/2 retardation layer] (Preparation of composition for forming retardation layer) The composition for forming a retardation layer for forming a λ/2 retardation layer is prepared by mixing the components shown below, stirring the resulting mixture at 80°C for 1 hour, and cooling to room temperature. ･LC242 (BASF, polymerizable liquid crystal compound): 20.3 parts ･Polymerization initiator (Irgacure 907, manufactured by BASF): 0.5 part ･Leveling agent (BYK-361N, polyacrylate compound, manufactured by BYK): 0.1 part ･Solvent (propylene glycol 1-monomethyl ether 2-acetate): 400 parts

(Production of λ/2 retardation layer) A cycloolefin polymer film (ZF-14 manufactured by Zeon, Japan, thickness 23 μm) that has not been stretched was prepared as a substrate. Using a corona treatment device (AGF-B10, manufactured by Kasuga Electric Co., Ltd.), the surface of the film was corona treated once at an output of 0.3 kW and a treatment speed of 3 m/min. The composition (2) for forming an alignment layer was applied to the corona-treated surface using a bar coater. Dry the coated film at 80°C for 1 minute, and use a polarized UV irradiation device (SPOT CURE SP-7; manufactured by Usio Electric Co., Ltd.) to coat the film with a cumulative light quantity of 100 mJ/cm ² Irradiate polarized light UV. The film thickness of the resulting alignment layer was 100 nm.

The composition for forming a retardation layer was coated on the alignment layer using a bar coater. At this time, the thickness of the coating film is adjusted by changing the thickness of the wire bar to control the retardation value. After the coating film was dried at 120°C for 1 minute, a high-pressure mercury lamp (Unicure VB-15201 BY-A, manufactured by Usio Electric Co., Ltd.) was used to irradiate ultraviolet rays to polymerize the polymerizable liquid crystal compound. Ultraviolet rays are irradiated in a nitrogen atmosphere and irradiated so that the cumulative light intensity at a wavelength of 365 nm is 1000 mJ/cm ² . The film thickness of the obtained retardation layer was 2 μm, and the retardation value was measured at a wavelength of 550 nm. As a result, Re(550)=270 nm and Rth(550)=138 nm. The obtained retardation layer is a λ/2 retardation layer.

[Preparation of composition for forming overcoat] The composition for forming the outer coating layer is composed of 100 parts of water, 3 parts of polyvinyl alcohol resin powder (KL-318, Kuraray (stock) manufacturing, average degree of polymerization 18000), as the 1.5 parts of polyamide epoxy resin (SR650 (30), manufactured by Sumika Chemtex (stock)) of the coupling agent was mixed and prepared.

[Production of Adhesive Layer 2] By mixing 70 parts of butyl acrylate, 20 parts of methyl acrylate, 2.0 parts of acrylic acid and 0.2 parts of a radical polymerization initiator (2,2'-azobisisobutyronitrile) at 55°C while stirring in a nitrogen atmosphere Under the reaction, an acrylic resin is obtained. 100 parts of the obtained acrylic resin, 1.0 part of crosslinking agent ("Coronate L" manufactured by Tosoh Co., Ltd.), and silane coupling agent ("X-12-X-12- manufactured by Shin-Etsu Chemical Co., Ltd.) 981”) 0.5 parts of mixing. Ethyl acetate was added so that the total solid content concentration was 10% to obtain an adhesive composition.

Using an applicator, the obtained adhesive composition was applied to the release-treated surface of the release-treated polyethylene terephthalate film (thickness 38 μm) so that the thickness after drying was 5 μm. The coating layer was dried at 100°C for 1 minute to obtain an adhesive layer 2. On the adhesive layer 2, another polyethylene terephthalate film (thickness 38 μm) that has been demolded is attached. Cure for 7 days under the conditions of temperature 23℃ and relative humidity 50%RH.

[Example 1] A triacetyl cellulose (TAC) film (KC2UA, manufactured by Konica Minolta Co., Ltd., thickness 25 μm) as a base layer was subjected to corona treatment. The conditions of corona treatment were set to output 0.3 kW and processing speed 3 m/min. After that, the composition for forming an alignment layer prepared above was coated on the corona-treated surface of the TAC film by a bar coating method, and heated and dried in a drying oven at a temperature of 80° C. for 1 minute. For the obtained film, the light irradiated from the UV irradiation device was transmitted through the wire grid (UIS-27132##, manufactured by Ushio Electric Co., Ltd.) and the cumulative light intensity measured at a wavelength of 365 nm was 100 mJ/ Under the condition of cm ² . The thickness of the alignment layer is 100 nm.

On the formed alignment layer, the polarizing layer forming composition prepared above was coated by a bar coating method, heated and dried in a drying oven at a temperature of 120° C. for 1 minute, and then cooled to room temperature. The obtained film was irradiated with ultraviolet rays so that the cumulative light amount was 1200 mJ/cm ² (365 nm reference) using the UV irradiation device to form a linear polarizing layer with a thickness of 1.8 μm.

On the formed linear polarizing layer, the composition for forming the overcoat layer prepared above was applied by bar coating so that the thickness after drying was 1.0 μm, and dried at a temperature of 80° C. for 3 minutes. In this way, a polarizing plate having a TAC film, an alignment layer, a linear polarizing layer, and an outer coating in this order is obtained.

The adhesive layer (X) of the adhesive sheet (x) prepared above was bonded to the overcoat side of the polarizing plate obtained, and the release film was peeled off. The λ/4 retardation layer side of the λ/4 retardation layer with the PET film prepared above is bonded to the adhesive layer (X) exposed by peeling the release film, and the PET film is peeled to obtain circular polarization board. The circularly polarizing plate has a TAC film, an alignment layer, a linear polarizing layer, an outer coating, an adhesive layer (X) and a λ/4 retardation layer in sequence.

Adhesive layers 1 (P-3132, manufactured by Lintec Co., Ltd., thickness 25 μm) are provided on both sides of the circular polarizing plate obtained above, and glass plates (Yico (EAGL) XG, manufactured by Corning (Corning), obtained a circular polarizing plate with a glass plate. When bonding the circular polarizing plate and the adhesive layer 1, corona treatment is applied to the surface. A wet heat test was performed on the obtained circular polarizing plate with glass plate. The results are shown in Table 1.

[Example 2] In addition to using a hard-coated TAC film (25KCHC, manufactured by Konica Minolta Co., Ltd., thickness 32 μm) as a laminate of a hard-coating layer and a substrate layer, instead of the triacetyl cellulose as the substrate layer (TAC) film, and forming an alignment layer and a linear polarizing layer on the TAC film side of the TAC film with a hard coat layer, a circular polarizing plate and a circular polarizing plate with a glass plate were obtained in the same manner as in Example 1. A wet heat test was performed on the obtained circular polarizing plate with glass plate. The results are shown in Table 1.

[Example 3] Except that the adhesive sheet (y) with the adhesive layer (Y) was used instead of the adhesive sheet (x) with the adhesive layer (X), the circular polarizing plate and the circle with glass plate were obtained in the same manner as in Example 1. Polarizing plate. A wet heat test was performed on the obtained circular polarizing plate with glass plate. The results are shown in Table 1.

[Example 4] In addition to using a hard-coated TAC film (25KCHC, manufactured by Konica Minolta Co., Ltd., thickness 32 μm) as a laminate of a hard-coating layer and a substrate layer, instead of the triacetyl cellulose as the substrate layer (TAC) film, and forming an alignment layer and a linear polarizing layer on the TAC film side of the TAC film with a hard coat layer, a circular polarizing plate and a circular polarizing plate with a glass plate were obtained in the same manner as in Example 3. A wet heat test was performed on the obtained circular polarizing plate with glass plate. The results are shown in Table 1.

[Comparative Example 1] Except that an acrylic adhesive layer (Z) (manufactured by Lintec Co., Ltd.) was used instead of the adhesive layer (X), a circular polarizing plate and a glass plate were obtained in the same manner as in Example 1. Circular polarizer. A wet heat test was performed on the obtained circular polarizing plate with glass plate. The results are shown in Table 1.

[Example 5] The circular polarizing plate obtained in Example 3 was prepared. The surface of the λ/4 retardation layer side of the circular polarizing plate was corona treated, and the adhesive layer 2 (acrylic adhesive layer, thickness 5 μm) produced above was laminated. A positive C layer is laminated on the adhesive layer 2 and the substrate is peeled off, thereby transferring the positive C layer. In this way, a circular polarizing plate having a TAC film, an alignment layer, a linear polarizing layer, an outer coating, an adhesive layer (Y), and a λ/4 retardation layer, an adhesive layer 2, and a positive C layer in this order are produced.

In the same manner as in Example 1, a circular polarizing plate with a glass plate was obtained. A wet heat test was performed on the obtained circular polarizing plate with glass plate. The results are shown in Table 1.

[Example 6] In the same manner as in Example 1, a polarizing plate having a TAC film, an alignment layer, a linear polarizing layer and an outer coating in this order was obtained. The adhesive layer 2 prepared above was bonded to the overcoat side of the polarizing plate obtained, and the release film was peeled off. On the adhesive layer 2 exposed by peeling the release film, the λ/2 retardation layer prepared above was bonded, and the base material was peeled off. The angle formed by the absorption axis of the polarizer and the slow axis of the λ/2 retardation layer is 15°. On the λ/2 retardation layer exposed by peeling the base material, the λ/4 retardation layer was bonded via the adhesive layer (Y) of the adhesive sheet (y), and the PET film was peeled off. The angle formed by the absorption axis of the polarizer and the slow axis of the λ/4 retardation layer is 75°. In this way, a circularly polarized light having a TAC film, an alignment layer, a linear polarizing layer, an overcoat, an adhesive layer 2, a λ/2 retardation layer, an adhesive layer (Y), and a λ/4 retardation layer in sequence is obtained board.

In the same manner as in Example 1, a circular polarizing plate with a glass plate was obtained. A wet heat test was performed on the obtained circular polarizing plate with glass plate. The results are shown in Table 1.

[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Comparative example 1 Example 5 Example 6 Adhesive layer species X X Y Y Z Y Y Water permeability [g/(m ² ·24 hr)] 30 30 50 50 1050 50 50 The presence or absence of hard coating no Have no Have no no no Damp heat test ΔReflectivity [%] 0.9 0.8 1.1 1.0 2.3 1.1 1.2 ΔRO[nm] -9 -10 -10 -11 -twenty two -11 -10 Appearance evaluation A A A A B A A Evaluation of ΔE B B B B B A A

Compared with the circular polarizing plate obtained in the comparative example, the circular polarizing plate obtained in the example has good optical properties even after the wet heat test. In particular, even after the damp heat test of the circular polarizing plate obtained in the embodiment, the phase difference value of the circular polarizing plate is not easy to change, and the reflectance is not easy to change when the circular polarizing plate is placed on the reflector, and it is difficult to see red. It has a good appearance.

11～14: Circular polarizing plate 21: Circular polarizing plate with glass plate 31: Hard coating 32: substrate layer 33: Linear polarizing layer 34: outer coating 36: Laminated layer 38: λ/4 retardation layer 41: glass plate 42: Laminating layer for glass plate

Fig. 1 is a schematic cross-sectional view schematically showing an example of the circularly polarizing plate of the present invention. Fig. 2 is a schematic cross-sectional view schematically showing another example of the circularly polarizing plate of the present invention. Fig. 3 is a schematic cross-sectional view schematically showing another example of the circularly polarizing plate of the present invention. Fig. 4 is a schematic cross-sectional view schematically showing another example of the circularly polarizing plate of the present invention. Fig. 5 is a schematic cross-sectional view schematically showing an example of the circularly polarizing plate with a glass plate of the present invention.

11: Circular polarizing plate

33: Linear polarizing layer

36: Laminated layer

38: λ/4 retardation layer

Claims (9)

A circular polarizing plate having a linear polarizing layer, a bonding layer, and a λ/4 retardation layer in this order, the linear polarizing layer containing a cured product of a polymerizable liquid crystal compound and a dichroic pigment, and the λ/4 phase The differential layer contains a cured product of a polymerizable liquid crystal compound, and the temperature of the bonding layer is 40° C. and the moisture permeability at 90% RH is 100 g/(m ² ·24 hr) or less. The circular polarizing plate according to claim 1, wherein the λ/4 retardation layer has reverse wavelength dispersion. The circular polarizing plate according to claim 1 or 2, wherein the bonding layer includes an adhesive composition. The circular polarizing plate according to claim 3, wherein the adhesive composition contains a rubber-based polymer. The circular polarizing plate according to any one of claims 1 to 4, which further has an outer coating on one or both sides of the linear polarizing layer. The circular polarizing plate according to any one of claims 1 to 5, which further has a base layer on the side of the linear polarizing layer opposite to the side of the bonding layer. The circular polarizing plate according to claim 6, which further has a hard coat layer on the side of the base layer opposite to the side of the linear polarizing layer. The circular polarizing plate according to any one of claim 1 to claim 7, which is for in-vehicle use. A circular polarizing plate with glass plates, which has glass plates on both sides of the circular polarizing plate as described in any one of Claims 1 to 8.

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