TW202332944A - Circularly polarizing plate and organic el display device - Google Patents

Abstract

An objective of this invention is to provid a circularly polarizing plate which contains an antistatic agent and is less likely to deteriorate the optical properties in moisty and hot environments, and an organic EL display device including the circularly polarizing plate.

This invention provides a circularly polarizing plate for an organic EL display device including a linear polarizing plate, a first pressure-sensitive adhesive layer, and a retardation layer structure including at least one retardation layer in this order, wherein the first pressure-sensitive adhesive layer contains an antistatic agent; this invention also provides an organic EL display device including the circularly polarizing plate.

Description

Circular polarizing plates and organic EL display devices

The present invention relates to a circularly polarizing plate and an organic EL display device.

Patent Document 1 describes an image display device including, from the viewing side, a circular polarizing plate having a linear polarizer and a retardation film, and an image display panel, in which the circular polarizer is The retardation film of the polarizing plate and the image display panel are joined by a pressure-sensitive adhesive containing an antistatic agent.

[Prior technical literature]

[Patent Document]

[Patent Document 1] Japanese International Publication No. 2019/160033

In the image display device described in Patent Document 1, in order to prevent the image display panel from being damaged due to static electricity, a circular polarizing plate having a linear polarizer and a retardation film is bonded to the image display panel. The pressure-sensitive adhesive for display panels contains antistatic agents. However, antistatic agents may cause deterioration in the optical properties of linear polarizers or retardation films in hot and humid environments.

The object of the present invention is to provide a circularly polarizing plate that contains an antistatic agent and is less likely to deteriorate in optical properties even in a hot and humid environment, and an organic electroluminescence (EL: Electroluminescence) display device including the circularly polarizing plate.

The present invention provides the following circular polarizing plate and organic EL display device.

[1] A circular polarizing plate for organic EL display devices,

The system includes in order: a linear polarizing plate, a first adhesive layer, and a retardation layer structure including at least one retardation layer.

The first adhesive layer contains an antistatic agent.

[2] A circular polarizing plate, including in order: a linear polarizing plate, a first adhesive layer, a retardation layer structure including at least one retardation layer, and a second adhesive layer,

Among the first adhesive layer and the second adhesive layer, only the first adhesive layer contains an antistatic agent.

[3] The circularly polarizing plate as described in [1] or [2], wherein the above-mentioned When the water vapor transmittance of the linear polarizing plate is W1 and the water vapor transmittance of the retardation layer structure is W2,

W1 is 5 [g/(m ² .24hr)] or more and 100 [g/(m ² .24hr)] or less,

W2 is 300 [g/(m ² .24hr)] or more and 900 [g/(m ² .24hr)] or less.

[4] The circular polarizing plate according to any one of [1] to [3], wherein the temperature is 40 as measured by the moisture sensor method specified in JIS K 7129-1:2019. When the water vapor transmittance of the linear polarizing plate is W1 at ℃ and the water vapor transmittance of the retardation layer structure is W2,

W1/W2 is 0.006 or more and 0.4 or less.

[5] The circularly polarizing plate according to any one of [1] to [4], wherein the content of the antistatic agent is 0.5 parts by mass or more relative to 100 parts by mass of the resin contained in the first adhesive layer 5 parts by mass or less.

[6] The circularly polarizing plate according to any one of [1] to [5], wherein the antistatic agent is an ionic compound.

[7] The circularly polarizing plate according to any one of [1] to [6], wherein the retardation layer is a liquid crystal hardened layer.

[8] The circular polarizing plate according to any one of [1] to [7], wherein the linear polarizing plate includes a linear polarizing plate and a protective film laminated on one or both sides of the linear polarizing plate.

[9] An organic EL display device including the circular polarizing plate according to any one of [1] to [8].

It is possible to provide a circularly polarizing plate that contains an antistatic agent and is less likely to deteriorate in optical properties even in a hot and humid environment, and an organic EL display device including the circularly polarizing plate.

1: Linear polarizing plate

1a,1c: protective layer

1b: Linear polarizer

1d: 1st laminating layer

2: Phase difference layer structure

2a: 1st phase difference layer

2b: 2nd phase difference layer

2c: 2nd laminating layer

2d: Thermoplastic resin film

2e: 3rd lamination layer

10: 1st adhesive layer

20: 2nd adhesive layer

21:Separation film

30:Protective film

40: The 4th laminating layer

50:Front panel

100: Organic EL display element

FIG. 1 is a schematic cross-sectional view showing an example of the circularly polarizing plate according to the present invention.

FIG. 2 is a schematic cross-sectional view showing another example of the circularly polarizing plate according to the present invention.

FIG. 3 is a schematic cross-sectional view showing another example of the circularly polarizing plate according to the present invention.

4 is a schematic cross-sectional view showing another example of the circularly polarizing plate according to the present invention.

FIG. 5 is a schematic cross-sectional view showing another example of the circularly polarizing plate according to the present invention.

FIG. 6 is a schematic cross-sectional view showing an example of the organic EL display device according to the present invention.

The embodiments of the present invention are described below with reference to the drawings, but the present invention is not limited to the following embodiments. All the following drawings are shown to assist in understanding the present invention. The size or shape of each component shown in the drawings is not necessarily consistent with the size or shape of the actual component.

〈Circular Polarizing Plate〉

FIG. 1 is a schematic cross-sectional view showing an example of a circularly polarizing plate (hereinafter also simply referred to as a "circularly polarizing plate") according to the present invention. The circularly polarizing plate of the present invention includes, in order, a linear polarizing plate 1, a first adhesive layer 10, and a retardation layer structure 2. The linear polarizing plate 1 and the first adhesive layer 10 are usually in contact, and the first adhesive layer 10 and the retardation layer structure 2 are usually in contact. The first adhesive layer 10 disposed between the linear polarizing plate 1 and the retardation layer structure 2 contains an antistatic agent. In addition, the term "circular polarizing plate" includes elliptically polarizing plates.

The circular polarizing plate according to the present invention is usually arranged on the viewing side of image display elements such as organic EL display elements. By arranging the circularly polarizing plate in this manner, external light incident on the image display element is reflected by the internal electrodes etc. included in the element and internally reflected light emitted to the outside can be suppressed. That is, the circularly polarizing plate is suitable as an antireflection film.

According to the circularly polarizing plate of the present invention, since the first adhesive layer 10 contains an antistatic agent, damage or failure of the image display element caused by static electricity can be prevented or suppressed. In addition, according to the circular polarizing plate of the present invention, since the first adhesive layer 10 disposed between the linear polarizing plate 1 and the retardation layer structure 2 contains an antistatic agent, compared with the adhesive layer attached to the image display element, The glue used in the combination When the adhesive layer contains an antistatic agent (as is the case in the image display device described in Patent Document 1), the optical properties are less likely to deteriorate in a hot and humid environment. Specifically, in a hot and humid environment, the optical properties (polarization degree and transmittance) of the linear polarizing plate 1 are less likely to be deteriorated, and the optical properties (phase difference properties) of the retardation layer structure 2 are less likely to be deteriorated. The deterioration (change) of the phase difference characteristics means the change in the reflection hue of the circularly polarizing plate. Suppressing the change in reflection hue is important when using a circularly polarizing plate as an antireflection film.

The deterioration of the optical properties of the circular polarizer caused by the antistatic agent in a hot and humid environment can be presumed to be due to the movement of the antistatic agent together with moisture from the adhesive layer containing the antistatic agent to other layers. In the circularly polarizing plate of the present invention, it is considered that the effect of suppressing the deterioration of optical characteristics caused by the antistatic agent in a hot and humid environment is higher than that of the structure described in Patent Document 1. In the plate, the moving direction of the antistatic agent is dispersed in two directions: the direction of the linear polarizing plate and the direction of the retardation layer structure. Therefore, the impact of the antistatic agent on the linear polarizing plate and the retardation layer structure is separated. Because of slowing down.

The following describes the circularly polarizing plate in more detail.

(1)Linear polarizing plate

The linear polarizing plate 1 series includes a linear polarizer. Linear polarizers have the function of selectively transmitting linearly polarized light in a certain direction from non-polarized light such as natural light. Examples of linear polarizers include a stretched film or stretched layer to which a dichroic dye is adsorbed, a cured liquid crystal layer containing a cured product of a polymerizable liquid crystal compound and a dichroic dye, and the like.

Linear polarizers, which are stretched films with adsorbed dichroic dyes, can usually be produced through the following steps: uniaxially stretching a polyvinyl alcohol-based resin film, and dyeing the polyvinyl alcohol with dichroic dyes such as iodine. The resin film is used to adsorb the dichroic pigment, and is treated with a boric acid aqueous solution. A step of physically adsorbing the polyvinyl alcohol-based resin film to which the dichroic pigment is adsorbed, and a step of washing with water after treatment with a boric acid aqueous solution.

The thickness of the stretched film to which the dichroic dye is adsorbed is usually 30 μm or less, preferably 18 μm or less, particularly preferably 15 μm or less. The thickness is usually 1 μm or more, and may be, for example, 5 μm or more.

Polyvinyl alcohol-based resin can be obtained by saponifying polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith can be used. Examples of other monomers copolymerizable with vinyl acetate include: unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated styrene compounds, and (meth)acrylamide having an ammonium group. system compound. In addition, "(meth)acrylic acid" in this specification means either acrylic acid or methacrylic acid. "(Meth)" in (meth)acrylate, etc. also has the same meaning.

The saponification degree of the polyvinyl alcohol-based resin is usually about 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. Polyvinyl alcohol resin can be modified, or aldehyde-modified polyvinyl formaldehyde, polyvinyl acetal, etc. can be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually from 1,000 to 10,000, preferably from 1,500 to 5,000.

A linear polarizer that is an extension layer to which a dichroic pigment is adsorbed can be produced by dyeing a uniaxially stretched polyvinyl alcohol-based resin film with a dichroic pigment to thereby adsorb the dichroic pigment. A step of treating the film on which the dichroic pigment is adsorbed with a boric acid aqueous solution, and a step of washing with water after the treatment with the boric acid aqueous solution.

Alternatively, the linear polarizing plate belonging to the extension layer to which the dichroic dye is adsorbed can be produced by the following steps: applying the coating liquid containing the above polyvinyl alcohol-based resin on the base material layer; The step of uniaxially stretching the laminate, the step of adsorbing the dichroic dye by dyeing the polyvinyl alcohol-based resin layer of the uniaxially stretched laminate with a dichroic dye, and treating the adsorption with a boric acid aqueous solution There are a step of forming a laminate of a dichroic dye and a step of washing with water after treatment with a boric acid aqueous solution. The base material layer can be assembled on the circular polarizer, or can be peeled off from the linear polarizer. The material and thickness of the base material layer may be the same as those of the thermoplastic resin film described below.

The polymerizable liquid crystal compound used to form the linear polarizer that is a liquid crystal hardened layer is a compound that has a polymerizable reactive group and exhibits 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 means a group that can participate in the polymerization reaction by active radicals or acids generated from the photopolymerization initiator. Examples of photopolymerizable reactive groups include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloxy, and oxirane ( Oxiranyl Group), Oxetanyl Group, etc. Among them, acryloxy group, methacryloyloxy group, vinyloxy group, oxirane group and oxyvinyl group are preferred, and acrylyloxy group is particularly preferred. The type of polymerizable liquid crystal compound is not particularly limited, and rod-shaped liquid crystal compounds, disk-shaped liquid crystal compounds, and mixtures thereof can be used. The liquid crystallinity of a polymeric liquid crystal compound can be a thermotropic liquid crystal or a rheotropic liquid crystal. When classifying a thermotropic liquid crystal based on the degree of order, it can be a nematic liquid crystal or a rheotropic liquid crystal. Smectic liquid crystal.

(Oxazine)色素、花青(Cyanine)色素、萘色素、偶氮色素及蒽醌(Anthraquinone)色素等，當中較佳為偶氮色素。偶氮色素可列舉：單偶氮色素、雙偶氮色素、三偶氮色素、四偶氮色素及茋(Stilbene)偶氮色素等，較佳為 雙偶氮色素及三偶氮色素。二色性色素可單獨使用或組合2種以上，較佳係組合3種以上。特佳係組合3種以上的偶氮化合物。二色性色素的一部分可具有反應性基，此外，亦可具有液晶性。 In the liquid crystal cured layer, the dichroic dye is dispersed and aligned in the cured product of the polymerizable liquid crystal compound. The dichroic dye used in the linear polarizer that is a liquid crystal hardened layer preferably has an absorption maximum wavelength in the range of 300 nm to 700 nm. Examples of the dichroic pigment include: acridine pigment,

(Oxazine) pigments, cyanine (Cyanine) pigments, naphthalene pigments, azo pigments and anthraquinone (Anthraquinone) pigments, etc., among which azo pigments are preferred. Examples of azo dyes include monoazo dyes, disazo dyes, trisazo dyes, tetrasazo dyes, and stilbene azo dyes, and disazo dyes and trisazo dyes are preferred. The dichroic pigment may be used alone or in combination of two or more types, preferably in combination of three or more types. The best series combines more than three kinds of azo compounds. A part of the dichroic dye may have a reactive group, and may also have liquid crystallinity.

The linear polarizer that is a liquid crystal hardened layer can be formed by coating a linear polarizer-forming composition containing a polymerizable liquid crystal compound and a dichroic dye on an alignment film formed on a base material layer, and coating the polymerizable liquid crystal with the linear polarizer. The compound is polymerized and hardened. The thickness of the alignment film is, for example, 5 nm or more and 1 μm or less. The composition for forming a linear polarizer can also be coated on the base material layer to form a coating film, and the coating film can be stretched together with the base material layer to form a linear polarizer. The base material layer used to form the linear polarizer can also be assembled on the polarizing plate.

Examples of the base material layer include thermoplastic resin films. Examples of the thermoplastic resin constituting the thermoplastic resin film include cellulose resins such as cellulose triacetate; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether resin; polyethylene resin; Polycarbonate resin; polyamide resin such as nylon or aromatic polyamide; polyimide resin; polyolefin resin such as polyethylene, polypropylene, ethylene-propylene copolymer; with ring system and norbornene Structure of cyclic polyolefin resin (also known as norbornene resin); (meth)acrylic resin; polyarylate resin; polystyrene resin; polyvinyl alcohol resin, etc. Among them, the thermoplastic resin film is preferably a cyclic polyolefin resin film, a cellulose ester resin film, a polyester resin film, or a (meth)acrylic resin film.

From the viewpoint of thinning, the thickness of the thermoplastic resin film is usually 300 μm or less, preferably 200 μm or less, particularly preferably 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, and usually 1 μm or more. For example, it is 5 μm or more or 20 μm or more.

A hard coat layer (HC layer) can be formed on the base material layer. The hard coat layer can be formed on one side of the base material layer or on both sides. By providing a hard coating, the hardness and scratch resistance can be improved. When a linear polarizer is formed on the hard coat layer of a base material layer having a hard coat layer, the hard coat layer can serve as a protective layer to be described later.

A composition for forming a linear polarizer containing a polymerizable liquid crystal compound and a dichroic dye, and a method for manufacturing a linear polarizer using the composition are exemplified by Japanese Patent Application Laid-Open No. 2013-37353 and Japanese Patent Application Laid-Open No. 2013-33249 The method described in the publication, Japanese Patent Application Laid-Open No. 2017-83843, etc. In addition to the polymerizable liquid crystal compound and the dichroic pigment, the linear polarizer forming composition may further contain additives such as solvents, polymerization initiators, cross-linking agents, leveling agents, antioxidants, plasticizers, and sensitizers. These components can be used individually by 1 type or in combination of 2 or more types.

The polymerization initiator that can be contained in the composition for forming a linear polarizer is a compound that can start the polymerization reaction of the polymerizable liquid crystal compound. From the point where the polymerization reaction can start under lower temperature conditions, photopolymerization is preferred. Sex initiators. Specific examples include photopolymerization initiators that generate active radicals or acids by the action of light. Among them, photopolymerization initiators that generate free radicals by the action of light are preferred. The content of the polymerization initiator is preferably not less than 1 part by mass and not more than 10 parts by mass, and particularly preferably not less than 3 parts by mass and not more than 8 parts by mass relative to 100 parts by mass of the total amount of the polymerizable liquid crystal compound. Within this range, the reaction of the polymerizable group proceeds sufficiently, and the alignment state of the liquid crystal compound is easily stabilized.

The thickness of the linear polarizer that is the liquid crystal hardened layer is usually 10 μm or less, preferably 0.5 μm or more and 8 μm or less, particularly preferably 1 μm or more and 5 μm or less.

The visual sensitivity corrected polarization degree Py of the linear polarizer is usually more than 95%, preferably more than 97%, particularly preferably more than 98%, more preferably more than 98.7%, still more preferably more than 99.5%, especially preferably more than 99.9% Above, it can also be above 99.99%. The visual sensitivity corrected polarization degree Py of linear polarizer can be more than 99.999% below or below 99.99%. The visual sensitivity corrected polarization degree Py can be measured using a spectrum analyzer with an integrating sphere ("V7100" manufactured by JASCO Corporation) and a 2-degree field of view (C light source) of "JIS Z 8701". Calculated based on sensitivity correction.

Improving the visual sensitivity of linear polarizers and correcting the polarization degree Py is beneficial to improving the anti-reflection function of circular polarizers. When the visual sensitivity correction polarization degree Py is less than 95%, the anti-reflection function may not be exerted.

The sensitivity-corrected single unit transmittance Ty of the linear polarizer is usually 41% or more, preferably 41.1% or more, particularly preferably 41.2% or more, and can be 42% or more, or 42.5% or more. The sensitivity-corrected monomer transmittance Ty of the linear polarizer is usually 50% or less, and can be 48% or less, or 46% or less, or 44% or less, or even 43% or less. When the sensitivity correction unit transmittance Ty is too high, the sensitivity correction polarization degree Py becomes too low, and the anti-reflection function of the circular polarizer may become insufficient. The visual sensitivity-corrected single-unit transmittance Ty can be obtained by using an integrated sphere spectrum analyzer ("V7100" manufactured by JASCO Corporation) and using the 2-degree field of view (C light source) of "JIS Z 8701" The transmittance is calculated by correcting the visual sensitivity.

The linear polarizing plate 1 may be a laminate of the above-mentioned base material layer and a linear polarizing plate that is a liquid crystal cured layer. Alternatively, the base material layer can be peeled off from the linear polarizer. The linear polarizing plate 1 containing the linear polarizer belonging to the liquid crystal hardened layer may or may not have an alignment film.

The linear polarizing plate 1 may have a protective layer for protecting the linear polarizing plate. The protective layer can be arranged on one side or both sides of the linear polarizer. When protective layers are laminated on both sides of the linear polarizer, the two protective layers may be of the same type or different types. The protective layer is, for example, an organic layer or an inorganic layer. The organic layer or the inorganic layer is a layer formed by coating, for example. The organic layer is a composition for forming a protective layer (for example, a (meth)acrylic resin composition, an epoxy resin composition, a polyimide resin composition etc.), a water-soluble resin layer (such as a polyvinyl alcohol-based resin layer), etc. The hardening type protective layer forming composition may be an active energy ray hardening type or a thermal hardening type. The inorganic layer may be formed of, for example, silicon oxide. When the protective layer is an organic layer, the protective layer may be what is called a hardcoat layer (HC layer) or an overcoat layer (OC layer). The protective layer can be directly formed on the above-mentioned base material layer or alignment film, or can also be directly formed on the linear polarizer.

When the protective layer is an organic layer, for example, an active energy ray curable protective layer forming composition can be coated on the above-mentioned base material layer or on the alignment film formed on the base material layer, and the active energy ray curable composition can be irradiated. The energy rays harden it to form a protective layer (eg HC layer). The protective layer may also be assembled on the circularly polarizing plate in a state where the base material layer is peeled off and removed. Examples of methods for applying the protective layer forming composition include spin coating. When the protective layer is an inorganic layer, the protective layer can be formed by, for example, sputtering, evaporation, or the like. The outer coating layer (OC layer) can be formed by directly coating on the surface of the linear polarizer, for example. The thickness of the protective layer is, for example, 0.1 μm or more and 10 μm or less, preferably 5 μm or less.

The protective layer may be a thermoplastic resin film. As the thermoplastic resin film, those described above can be used. When the protective layer is a thermoplastic resin film, the thermoplastic resin film is bonded to the linear polarizer via a bonding layer to be described later, for example. The bonding layer is preferably an adhesive layer. Alternatively, the linear polarizer may be formed on the protective layer. The circular polarizing plate is preferably provided with at least one protective layer selected from the group consisting of a thermoplastic resin film and a hardened material layer on the side opposite to the first adhesive layer of the linear polarizing plate. FIG. 2 is a schematic cross-sectional view showing another example of a circularly polarizing plate. In the circular polarizing plate shown in FIG. 2, the linear polarizing plate 1 includes: a linear polarizing plate 1b, a protective layer 1a bonded to one surface of the linear polarizing plate 1b through a first bonding layer 1d, and a protective layer 1a bonded to one surface of the linear polarizing plate 1b through a first bonding layer 1d. 1. The bonding layer 1d is bonded to the protective layer 1c on the other side of the linear polarizer 1b.

(2) Phase difference layer structure

As shown in FIG. 2 , the circularly polarizing plate includes a retardation layer structure 2 , and the retardation layer structure 2 includes at least one retardation layer, that is, a first retardation layer 2 a . The retardation layer structure 2 may have only the first retardation layer 2a, or may have a laminated structure composed of two or more retardation layers. That is, the retardation layer structure 2 may include one or more retardation layers different from the first retardation layer 2a (for example, the second retardation layer 2b shown in FIG. 2).

The first phase difference layer 2a is, for example, a λ/4 layer. When the retardation layer structure 2 includes two retardation layers, the combination of the retardation layers can be listed as follows: from the linear polarizing plate 1 side, the combination of the λ/4 layer and the positive C layer, the λ/2 layer and The combination of λ/4 layer, the combination of positive C layer and λ/4 layer. The second bonding layer 2c can be used for laminating the retardation layers.

The in-plane phase difference value Re (550) of the λ/4 layer at a wavelength of 550 nm is usually in the range of 90 nm to 220 nm, preferably in the range of 100 nm to 200 nm. The in-plane phase difference value Re (550) of the λ/2 layer at a wavelength of 550 nm is preferably in the range of 200 nm to 300 nm. In addition, the phase difference value Rth (550) of the positive C layer in the thickness direction at a wavelength of 550 nm is usually in the range of -170 nm or more and below 10 nm, preferably in the range of -150 nm or above - 20 nm or below.

From the viewpoint of effectively suppressing the above-mentioned internal reflection, the retardation layer structure 2 preferably has reverse wavelength dispersion, particularly preferably the wavelength dispersion α is 0.95 or less, more preferably the wavelength dispersion α is 0.80 or more and 0.93 or less. More preferably, the wavelength dispersion α is from 0.80 to 0.90, and particularly preferably, the wavelength dispersion α is from 0.80 to 0.88. The so-called wavelength dispersion α is the ratio of the in-plane phase difference value Re (450) at a wavelength of 450 nm to the in-plane phase difference value Re (550) at a wavelength of 550 nm.

Wavelength dispersion α=in-plane phase difference value Re(450)/in-plane phase difference value Re(550)

The first retardation layer 2a and other retardation layers may be retardation films formed from the above-mentioned thermoplastic resin film by stretching or the like, or may be a liquid crystal cured layer. The liquid crystal hardened layer is a polymeric liquid crystal compound A hardened material layer that is polymerized and hardened in an aligned state. The phase difference layer structure 2 preferably includes one or more liquid crystal hardened layers, and may also include two or more layers.

Examples of the polymerizable liquid crystal compound include rod-shaped polymerizable liquid crystal compounds and disk-shaped polymerizable liquid crystal compounds. One of these compounds or a mixture containing both of these compounds can be used. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the base material layer, the optical axis of the polymerizable liquid crystal compound is consistent with the long axis direction of the polymerizable liquid crystal compound. When the disc-shaped polymerizable liquid crystal compound is aligned, the optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the disc surface of the polymerizable liquid crystal compound.

In order for the liquid crystal hardened layer formed by polymerizing the polymerizable liquid crystal compound to exhibit an in-plane phase difference, it is only necessary to align the polymerizable liquid crystal compound in an appropriate direction. When the polymerizable liquid crystal compound is rod-shaped, the in-plane phase difference is expressed by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the base material layer. In this case, the direction of the optical axis and the slow axis The direction is consistent. When the polymerizable liquid crystal compound is disk-shaped, the in-plane phase difference is expressed by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the base material layer. In this case, the optical axis and the slow axis Orthogonal. The alignment state of the polymerizable liquid crystal compound can be adjusted by the combination of the alignment film and the polymerizable liquid crystal compound.

The polymerizable liquid crystal compound is a compound that has at least one polymerizable reactive group and has liquid crystallinity. When two or more types of polymerizable liquid crystal compounds are used in combination, it is preferred that at least one type has two or more polymerizable reactive groups in the molecule. The polymerizable reactive group is a group that participates in the polymerization reaction, and is preferably a photopolymerizable reactive group. The photopolymerizable reactive group means a group that can participate in the polymerization reaction by active radicals or acids generated from the photopolymerization initiator. Examples of photopolymerizable reactive groups are the same as those described above. gather The liquid crystallinity possessed by a synthetic liquid crystal compound can be a thermotropic liquid crystal or a rheologically viscosity-increasing liquid crystal. When classifying a thermotropic liquid crystal based on the degree of order, it can be a nematic liquid crystal or a smectic liquid crystal.

The retardation layer structure 2 may include an alignment film adjacent to the retardation layer. The alignment film system has an alignment regulating force that aligns the polymerizable liquid crystal compound in a desired direction. The alignment film may be a vertical alignment film in which the molecular axis of the polymerizable liquid crystal compound is aligned vertically with respect to the base material layer, or a horizontal alignment film in which the molecular axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the base material layer, or It may be an inclined alignment film in which the molecular axis of the polymerizable liquid crystal compound is aligned obliquely with respect to the base material layer.

The thickness of the liquid crystal hardened layer may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, or 2 μm or more. In addition, it is preferably 10 μm or less, 8 μm or less, or 5 μm or less. The thickness of the alignment film is, for example, 5 nm or more and 1 μm or less.

The liquid crystal cured layer can be formed by applying a liquid crystal layer forming composition containing a polymerizable liquid crystal compound on the base material layer and drying the composition to polymerize the polymerizable liquid crystal compound. The liquid crystal layer forming composition can also be coated on the alignment film formed on the base material layer. The material and thickness of the base material layer may be the same as those of the above-mentioned thermoplastic resin film. The base material layer can be assembled in the retardation layer structure 2 together with the retardation layer belonging to the liquid crystal hardened layer. The base material layer can also be peeled off and only the liquid crystal hardened layer or the liquid crystal hardened layer and the alignment film can be assembled in the retardation layer. Structure 2.

In the example of the circularly polarizing plate shown in FIG. 2 , the retardation layer structure 2 includes a first retardation layer 2 a and a second retardation layer 2 b, which are bonded by a second bonding layer 2 c. However, the second bonding layer 2c and the second phase difference layer 2b can be omitted. In the example of the circularly polarizing plate shown in FIG. 2 , the linearly polarizing plate 1 includes a linearly polarizing plate 1b and protective layers 1a and 1c laminated on both sides of the linearly polarizing plate 1b with a first bonding layer 1d interposed therebetween. However, either of the protective layers 1a and 1c can be omitted.

The retardation layer structure 2 may also include layers other than the retardation layer and the alignment film. Examples of such layers include layers not intended to express phase differences, and examples include unstretched films. The above-described thermoplastic resin film can be used as the unstretched film. FIG. 3 shows an example in which the retardation layer structure 2 includes a thermoplastic resin film 2d. In the example shown in FIG. 3 , the thermoplastic resin film 2d is bonded to the second retardation layer 2b via the third bonding layer 2e. However, the thermoplastic resin film 2d can also be bonded to the alignment film. By including the thermoplastic resin film 2d in the retardation layer structure 2, the water vapor transmittance W2 of the retardation layer structure 2 can be adjusted in a decreasing direction. In addition, the second adhesive layer described later is not included in the retardation layer structure 2 .

The thermoplastic resin film 2d may have a hard coat layer. The hard coat layer may be formed on one side of the thermoplastic resin film 2d, or may be formed on both sides. Regarding the hard coat layer, the above description is cited. The water vapor transmittance W2 of the retardation layer structure 2 can also be adjusted by the presence or absence of the hard coat layer.

(3) Water vapor transmittance of linear polarizing plates and retardation layer structures

In order to prevent the optical characteristics of the circular polarizing plate from deteriorating in a hot and humid environment, especially the phase difference characteristics of the retardation layer structure 2, the linear polarizing plate 1 and the retardation layer structure 2 preferably have an appropriate range. Water vapor penetration. Specifically, the water vapor transmittance W1 of the linear polarizing plate 1 is preferably smaller than the water vapor transmittance W2 of the retardation layer structure 2 . If the above-described deterioration can be suppressed when the water vapor transmittances of the two are in this relationship, it can be inferred that excessive intrusion of water vapor when viewed from above can be suppressed, and the movement of the antistatic agent can be easily adjusted appropriately. Therefore, in order to avoid the above-mentioned degradation, W1<W2 is more advantageous than W1=W2 or W1>W2.

The so-called water vapor penetration in this manual refers to the water vapor penetration at a temperature of 40°C measured by the humidity sensor method specified in JIS K 7129-1:2019. In more detail, That is, it is measured by the method described in the item of Example mentioned later.

In order to suppress the above-mentioned deterioration more effectively, it is preferable that the water vapor transmittance W1 and W2 satisfy at least one of the following [a] and [b], and more preferably satisfy both. The unit of water vapor penetration W1 and W2 is g/(m ² .24hr).

[a] W1 is 5 to 100 and W2 is 300 to 900.

[b]W1/W2 is 0.006 or more and 0.4 or less.

Regarding [a], when W1 is 5 or more, it is advantageous in terms of suppressing the intrusion of water vapor when viewed from above, and when W1 is 100 or less, it is advantageous to appropriately diffuse the antistatic agent in the linear polarizing plate 1 and the retardation layer. From the point of view of structure 2, it is advantageous. In addition, when W2 is 300 or more, it is advantageous to suppress the deterioration of the phase difference characteristics of the retardation layer structure 2, and when it is 900 or less, it is advantageous to suppress the deterioration of the optical characteristics of the circular polarizing plate. .

From the viewpoint of suppressing the above-mentioned deterioration more effectively, W1 is preferably 10 or more and 90 or less, particularly preferably 15 or more and 85 or less, more preferably 20 or more and 80 or less, particularly preferably 30 or more and 60 or less. In addition, from the viewpoint of suppressing the above-described deterioration more effectively, W2 is preferably 350 or more and 850 or less, particularly preferably 400 or more and 800 or less, more preferably 450 or more and 750 or less, particularly preferably 500 or more and 700 or less.

From the viewpoint of suppressing the above-mentioned deterioration more effectively, the difference between W2 and W1 is preferably 500 or more, more preferably 600 or more, more preferably 700 or more, and particularly preferably 800 or more. The difference between W2 and W1 is usually less than 850.

Regarding [b], when W1/W2 is 0.006 or more, it is advantageous for the protection of the linear polarizing layer, and when it is 0.4 or less, it is advantageous for the protection of the retardation layer structure 2 . From the viewpoint of suppressing the above-described deterioration more effectively, W1/W2 is preferably 0.010 or more and 0.26 or less, particularly preferably 0.015 or more and 0.20 or less, more preferably 0.025 or more and 0.18 or less, particularly preferably 0.05 or more and 0.1 or less.

The water vapor transmittance W1 of the linear polarizing plate 1 can be adjusted by, for example, the material, number, and film thickness of the combined protective layers. In addition, it can also be adjusted by providing a coating layer such as a hard coat or an antistatic coating on the protective layer, or by appropriately selecting an adhesive composition when joining the linear polarizing plate and the protective layer. The water vapor transmittance W2 of the retardation layer structure 2 can also be adjusted by the same method.

(4) 1st adhesive layer

The first adhesive layer 10 interposed between the linear polarizing plate 1 and the retardation layer structure 2 and used to bond the two is an antistatic adhesive layer containing an antistatic agent. The first adhesive layer 10 may be composed of an adhesive composition containing a matrix polymer and an antistatic agent. The adhesive layer may be, for example, a layer composed of an adhesive composition, or a layer obtained by subjecting this layer to some kind of treatment. The so-called adhesive is also called pressure-sensitive adhesive. The so-called "adhesive" in this specification refers to adhesives other than adhesives (pressure-sensitive adhesives) and is clearly distinguished from adhesives.

Examples of the matrix polymer include (meth)acrylic resins, rubber-based resins, urethane-based resins, ester-based resins, polysiloxane-based resins, polyvinyl ether-based resins, and the like. Among them, (meth)acrylic resin is more suitable because of its excellent transparency, weather resistance, heat resistance, etc. The adhesive composition may be an active energy ray hardening type or a heat hardening type.

(Meth)acrylic resins are suitable for use: butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. ( A polymer or copolymer of one or more meth)acrylates as monomers. In (meth)acrylic resin, it is preferable to copolymerize polar monomers. Examples of polar monomers include: (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-di(meth)acrylate Methylaminoethyl Monomers with polar groups such as carboxyl group, hydroxyl group, amide group, amine group, and epoxy group, etc., such as ester and glycidyl (meth)acrylate.

Examples of antistatic agents include ionic compounds. An ionic compound is a compound having inorganic cations or organic cations, and inorganic anions or organic anions. The first adhesive layer 10 may contain two or more ionic compounds.

Examples of inorganic cations include alkali metal ions such as lithium cation [Li ⁺ ], sodium cation [Na ⁺ ], and potassium cation [K ⁺ ]; beryllium cation [Be ²⁺ ], magnesium cation [Mg ²⁺ ], and calcium Cations [Ca ²⁺ ] and other alkaline earth metal ions, etc. Examples of organic cations include imidazolium cations, Pyridinium cations, Pyrrolidinium cations, ammonium cations, Sulfonium cations, and Phosphonium cations. The organic cationic component has excellent compatibility with the matrix polymer, so it is suitable for use.

Examples of inorganic anions include chloride anion [Cl ^- ], bromide anion [Br ^- ], iodide anion [I ^- ], tetrachloroaluminate anion [AlCl ₄ ^- ], and heptachlorodialuminate anion [Al ₂ Cl ₇ ^- ], tetrafluoroborate anion [BF ₄ ^- ], hexafluorophosphate anion [PF ₆ ^- ], perchlorate anion [ClO ₄ ^- ], nitrate anion [NO ₃ ^- ], hexafluoroarsenate Anion [AsF ₆ ^- ], hexafluorantimonate anion [SbF ₆ ^- ], hexafluoroniobate anion [NbF ₆ ^- ], hexafluorotantalate anion [TaF ₆ ^- ], dicyandiamide anion [(CN) ₂ N ^- ]etc.

Examples of organic anions include acetate anion [CH ₃ COO ^- ], trifluoroacetate anion [CF ₃ COO ^- ], methanesulfonate anion [CH ₃ SO ₃ ^- ], and trifluoromethanesulfonate anion [CF ₃ SO ₃ ^- ], p-toluenesulfonate anion [p-CH ₃ C ₆ H ₄ SO ₃ ^- ], bis(fluorosulfonyl)imide anion [(FSO ₂ ) ₂ N ^- ], bis(trifluoromethanesulfonate) acyl)acyl imine anion [(CF ₃ SO ₂ ) ₂ N ^- ], trifluoromethanesulfonyl methyl anion [(CF ₃ SO ₂ ) ₃ C ^- ], dimethylphosphonate anion [(CH ₃ ) ₂ POO ^- ], (poly)fluorinated hydrofluoride anion [F(HF) _n ^- ] (n is about 1 to 3), thiocyanate anion [SCN ^- ], perfluorobutanesulfonate anion [ C ₄ F ₉ SO ₃ ^- ], bis(pentafluoroethanesulfonyl)imide anion [(C ₂ F ₅ SO ₂ ) ₂ N ^- ], perfluorobutyrate anion [C ₃ F ₇ COO ^- ], (trifluoromethanesulfonyl)(trifluoromethanecarbonyl)imide anion [(CF ₃ SO ₂ )(CF ₃ CO)N ^- ], perfluoropropane-1,3-disulfonate anion [ ^- O ₃ S(CF ₂ ) ₃ SO ₃ ^- ], carbonate anion [CO ₃ ^2- ], etc.

Among the above-mentioned anionic components, in particular, anionic components containing fluorine atoms are suitable for use because they provide ionic compounds with excellent antistatic properties. Specific examples include bis(fluorosulfonyl)imide anion, hexafluorophosphate anion, or bis(trifluoromethanesulfonyl)imide anion.

Specific examples of the ionic compound can be appropriately selected from a combination of the above-mentioned cationic components and anionic components. When classifying and revealing examples of ionic compounds having organic cations based on their different structures, the following can be cited.

Pyridinium: N-hexylpyridinium hexafluorophosphate, N-octylpyridinium hexafluorophosphate, N-octyl-4-methylpyridinium hexafluorophosphate, N-butyl-4-methylpyridine Onium hexafluorophosphate, N-decylpyridinium bis(fluorosulfonyl)imide, N-dodecylpyridinium bis(fluorosulfonyl)imide, N-tetradecylpyridinium bis( Fluorosulfonyl)imide, N-cetylpyridinium bis(fluorosulfonyl)imide, N-dodecyl-4-methylpyridinium bis(fluorosulfonyl)imide, N-tetradecyl-4-methylpyridinium bis(fluorosulfonyl)imide, N-hexadecyl-4-methylpyridinium bis(fluorosulfonyl)imide, N-benzyl-2-methylpyridinium bis(fluorosulfonyl)imide, N-benzyl-4-methylpyridinium bis(fluorosulfonyl)imide, N-hexylpyridinium bis (Trifluoromethanesulfonyl)imide, N-octylpyridinium bis(trifluoromethanesulfonyl)imide, N-octyl-4-methylpyridinium bis(trifluoromethanesulfonyl) ) acyl imine, N-butyl-4-methylpyridinium bis(trifluoromethanesulfonyl) acyl imide.

Imidazolium: 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium p-toluenesulfonate, 1-ethyl-3-methylimidazolium bis(fluorine Sulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium methanesulfonate, 1- Butyl-3-methylimidazolium bis(fluorosulfonyl)imide.

Pyrrolidine salt: N-butyl-N-methylpyrrolidine salt hexafluorophosphate, N-butyl-N-methylpyrrolidine salt bis(fluorosulfonyl)imide, N-butyl-N - Methylpyrrolidinium salt bis(trifluoromethanesulfonyl)imide.

Quaternary ammonium salts: tetrabutylammonium hexafluorophosphate, tetrabutylammonium p-toluenesulfonate, (2-hydroxyethyl)trimethylammonium bis(trifluoromethanesulfonyl)amide, (2-hydroxyethyl) )trimethylammonium dimethylphosphonate.

Examples of ionic compounds having inorganic cations include the following. Lithium bromide, lithium iodide, lithium tetrafluoroborate, lithium hexafluorophosphate, lithium thiocyanate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium bis(fluorosulfonate)imide, bis(trifluoromethanesulfonate) )Lithium acyl imide, lithium bis(pentafluoroethane sulfonyl) acyl imide, lithium tris(trifluoromethanesulfonyl) methide, lithium p-toluenesulfonate, sodium hexafluorophosphate, bis(fluorosulfonate) Sodium acyl) imide, sodium bis(trifluoromethanesulfonyl) imide, sodium p-toluenesulfonate, potassium hexafluorophosphate, potassium bis(fluorosulfonyl) imide, bis(trifluoromethane) Potassium sulfonyl)imide, potassium p-toluenesulfonate.

Among these plasma compounds, from the viewpoint of suppressing the deterioration of optical properties in a hot and humid environment, which is the effect of the present invention, pyridinium is preferred, and among pyridinium, N-octyl-4-methyl is particularly preferred. pyridinium hexafluorophosphate, N-decylpyridinium bis(fluorosulfonyl)imide, more preferably N-decylpyridinium bis(fluorosulfonyl)imide.

The ionic compound is preferably solid at room temperature. Compared with the case of using ionic compounds that are liquid at room temperature, antistatic properties can be maintained for a longer period of time. From the viewpoint of such long-term stability of antistatic properties, the ionic compound preferably has a melting point of 30°C or higher, more preferably 35°C or higher. On the other hand, if the melting point is too high, the compatibility with the matrix polymer becomes poor, so the melting point is preferably 90°C or lower, more preferably 70°C or lower, and more preferably less than 50°C.

The content of the antistatic agent is usually 0.2 to 8 parts by mass relative to 100 parts by mass of the resin (matrix polymer) contained in the first adhesive layer 10, preferably 0.3 to 5 parts by mass, especially Preferably, it is not less than 0.5 parts by mass and not more than 5 parts by mass, more preferably not less than 0.5 parts by mass and not more than 4 parts by mass, and particularly preferably not less than 1 part by mass and not more than 3.5 parts by mass. When the content of the ionic compound is within the above range, it is advantageous to simultaneously ensure sufficient antistatic performance and maintain the durability of the adhesive layer.

The adhesive composition may further contain a cross-linking agent. Examples of the cross-linking agent include metal ions having a valence of more than divalent and forming a carboxylic acid metal salt with the carboxyl group, polyamine compounds that form an amide bond with the carboxyl group, and ester bonds with the carboxyl group. Polyepoxy compounds or polyols, polyisocyanate compounds that form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferred. The content of the cross-linking agent is usually from 0.1 to 1 part by mass relative to 100 parts by mass of the resin (matrix polymer) contained in the first adhesive layer 10 .

The active energy ray curable adhesive composition has the property of being hardened by irradiation with active energy rays such as ultraviolet rays or electron beams. It also has adhesive properties and can adhere closely to films, etc. even before irradiation with active energy rays. The adherend is hardened by the irradiation of active energy rays and the properties of the adhesive force can be adjusted. The active energy ray curing adhesive composition is preferably an ultraviolet curing type. The active energy ray hardening adhesive composition further contains an active energy ray polymerizable compound. Photopolymerization initiators, photosensitizers, etc. may also be included as needed.

The adhesive composition constituting the first adhesive layer 10 may contain components other than those mentioned above. Examples of the other ingredients include: silane compounds, cross-linking catalysts, weathering stabilizers, antioxidants, adhesives, plasticizers, softeners, dyes, pigments, inorganic fillers, light-scattering fine particles and other additives.

The thickness of the first adhesive layer 10 is, for example, 250 μm or less. From the viewpoint of thinning, the thickness is preferably 100 μm or less, particularly preferably 50 μm or less, and more preferably 40 μm or less. From the viewpoint of durability, the lower limit of the thickness of the adhesive layer is, for example, 1 μm or more, preferably 5 μm or more, and particularly preferably 10 μm or more.

(5) 2nd adhesive layer

As shown in FIGS. 2 and 3 , the circularly polarizing plate may include the second adhesive layer 20 laminated on the surface opposite to the viewing side (the linear polarizing plate 1 side). Circular polarizing plates are suitable for use in image display devices such as organic EL display devices. When applied to an image display device, the circular polarizing plate is arranged in such a way that the linear polarizing plate 1 side becomes the viewing side, that is, the retardation layer structure 2 side becomes the image display element side. The visible side of the display element. The second adhesive layer 20 can be used to bond the circular polarizing plate to the image display element.

Regarding the structure of the second adhesive layer 20, the description of the first adhesive layer 10 is quoted. However, the second adhesive layer 20 is preferably substantially free of antistatic agents. The so-called substantially does not include, means relative to The second adhesive layer 20 contains 100 parts by mass of the resin (matrix polymer) and the content of the antistatic agent is 0.1 parts by mass or less. The content is preferably 0.05 parts by mass or less, particularly preferably 0.01 parts by mass or less, and even more preferably is 0 parts by mass. The fact that the second adhesive layer 20 does not substantially contain an antistatic agent is advantageous in that it is less likely to cause deterioration of the optical properties of the circular polarizer in a hot and humid environment, especially the deterioration of the retardation properties of the retardation layer structure.

A circularly polarizing plate according to an embodiment of the present invention includes, in order: a linear polarizing plate 1, a first adhesive layer 10, a phase difference layer structure 2, a second adhesive layer 20, and a first adhesive layer. The layer 10 contains an antistatic agent, and the second adhesive layer 20 does not substantially contain an antistatic agent. The circularly polarizing plate according to other embodiments of the present invention includes, in order: a linear polarizing plate 1, a first adhesive layer 10, a phase difference layer structure 2, a second adhesive layer 20, and a first adhesive layer. Among the first adhesive layer 10 and the second adhesive layer 20 , only the first adhesive layer 10 contains an antistatic agent.

(6)Separation film

As shown in FIG. 4 , the circularly polarizing plate may include a separation film 21 for protecting the outer surface of the second adhesive layer 20 (the surface opposite to the second retardation layer 2b). The circularly polarizing plate shown in FIG. 4 has the same layer structure as the circularly polarizing plate shown in FIG. 2 except for the separation film 21 . The separator film 21 is usually composed of a thermoplastic resin film that has been subjected to a release treatment using a silicone-based, fluorine-based plasma release agent or the like on one side, and the release-treated surface is bonded to 2nd adhesive layer 20.

The thermoplastic resin constituting the separator film 21 is, for example, polyethylene-based resin such as polyethylene, polypropylene-based resin such as polypropylene, polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate, and the like. The thickness of the separation film 21 is, for example, 10 μm or more and 50 μm or less.

(7)Protective film

As shown in FIG. 5 , the circular polarizing plate may include a protective film 30 laminated on the surface of the linear polarizing plate 1 . Except for the protective film 30 , the circularly polarizing plate shown in FIG. 5 has the same layer structure as the circularly polarizing plate shown in FIG. 4 . The protective film 30 is composed of, for example, a base film and an adhesive layer laminated thereon. Regarding the adhesive layer, the description of the above-mentioned second adhesive layer 20 is quoted. The resin constituting the base film may be, for example, polyethylene-based resin like polyethylene, polypropylene-based resin like polypropylene, polyethylene terephthalate, or polyester-based resin like polyethylene naphthalate. , polycarbonate resin and other thermoplastic resins. Preferred are polyester-based resins such as polyethylene terephthalate.

(8) Lamination layer

The circularly polarizing plate may include a laminating layer for bonding two layers (or films). Examples of the laminating layers include: a first laminating layer 1d that laminates the linear polarizer 1b and the protective layers 1a and 1c; a second laminating layer 2c that laminates the first retardation layer 2a and the second retardation layer 2b; The second retardation layer 2b (or the first retardation layer 2a) and the third bonding layer 2e of the thermoplastic resin film 2d are combined.

The laminating layer is an adhesive layer composed of an adhesive composition or an adhesive layer composed of an adhesive composition. Regarding the adhesive layer, the description of the above-mentioned second adhesive layer 20 is quoted.

Examples of the adhesive composition include water-based adhesives, active energy ray-curable adhesives, and the like. Examples of water-based adhesives include polyvinyl alcohol-based resin aqueous solutions, water-based two-liquid urethane-based emulsion adhesives, and the like. Active energy ray curable adhesives are adhesives that are cured by irradiation with active energy rays such as ultraviolet rays. Examples include adhesives containing a polymerizable compound and a photopolymerizable initiator, adhesives containing a photoreactive resin, Adhesives containing adhesive resin and photoreactive cross-linking agent, etc. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth)acrylic monomers, and photocurable urethane monomers, and photopolymerizable monomers derived from these. Monomers, oligomers, etc. The above photocondensation Examples of the co-initiator include compounds containing substances that generate active species such as neutral radicals, anionic radicals, and cationic radicals when irradiated with active energy rays such as ultraviolet rays.

The thickness of the bonding layer composed of the adhesive composition may be, for example, 0.1 μm or more, preferably 0.5 μm or more, 1 μm or more, or 2 μm or more, and may be 100 μm or less, 50 μm or less, 25 μm or less, 15 μm or less, or 5 μm or less. The two opposing surfaces to be bonded across the bonding layer can be subjected to surface activation treatments such as corona treatment, plasma treatment, and flame treatment in advance.

〉Image display device〉

The image display device according to the present invention (hereinafter also simply referred to as "image display device") includes the circular polarizing plate according to the present invention and an image display element. Examples of the image display device include image display devices such as organic electroluminescence (organic EL) display devices, inorganic electroluminescence (inorganic EL) display devices, liquid crystal display devices, field emission display devices, etc., and organic EL is preferred. display device. In an organic EL display device, the circular polarizing plate functions as an anti-reflection film to suppress internally reflected light. The image display device may also have a touch panel function, a blue light blocking function, a viewing angle adjustment function, etc.

In the image display device, the circular polarizing plate is arranged on the viewing side of the image display element. The second adhesive layer 20 can be used to bond the circular polarizing plate to the image display element. The image display device can be used as portable devices such as smartphones and tablets, televisions, digital photo frames, electronic signs, measuring instruments or measuring instruments, office equipment, medical equipment, computer equipment, etc.

6 is a schematic cross-sectional view showing an example of an organic EL display device as an example of the image display device according to the present invention. In FIG. 6 , the circular polarizing plate shown in FIG. 3 is used as an example of the circular polarizing plate. The circular polarizing plate is bonded to the organic EL display element 100 using the second adhesive layer 20 .

On the surface of the circularly polarizing plate opposite to the second adhesive layer 20 (the surface of the outermost layer on the viewing side), the front panel 50 may be laminated with the fourth bonding layer 40 interposed therebetween. Regarding the fourth bonding layer 40, the description of the bonding layer mentioned above is quoted.

The front panel 50 is the outermost surface constituting the viewing side of the image display device, and may have the function of protecting the front surface (screen) of the image display device. The front panel 50 may also be called a window film. The material and thickness of the front panel 50 are not limited as long as it is a plate-shaped body that allows light to pass through. In addition, the front panel 50 may be composed of only one layer or two or more layers. Examples of the front panel 50 include a resin plate-shaped body (such as a resin plate, a resin sheet, a resin film, etc.), a glass plate-shaped body (such as a glass plate, a glass film, etc.), and a touch sensor panel described below. When the front panel 50 is provided on the circularly polarizing plate, the front panel 50 is disposed on the viewing side of the circularly polarizing plate.

The thickness of the front panel 50 is, for example, 30 μm or more and 500 μm or less, preferably 200 μm or less, particularly preferably 100 μm or less.

Examples of the resin constituting the resinous plate-like body include cellulose triacetate, cellulose acetate butyrate, ethylene-vinyl acetate copolymer, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and polyethylene glycol. Ester, polystyrene, polyamide, polyether imide, poly(meth)acrylic acid, polyimide, polyether styrene, polystyrene, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride , polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether ester, polymethyl methacrylate, polyethylene terephthalate, polyterephthalic acid Butylene glycol, polyethylene naphthalate, polycarbonate, polyamide imide and other thermoplastic resins. These thermoplastic resins can be used individually or in mixture of 2 or more types. From the viewpoint of improving strength and transparency, the resin plate-shaped body is preferably a thermoplastic resin film formed of polyamide, polyamide, polyamide, etc.

From the viewpoint of hardness, the front panel 50 is preferably a film provided with a hard coat layer (HC layer) on at least one side of the base film. As the base film, a film composed of the above-mentioned thermoplastic resin can be used. The hard coat layer can be formed on one side of the base film or on both sides. By providing a hard coating layer, a front panel with improved hardness and scratch resistance can be formed. The hard coat layer is, for example, a cured layer of ultraviolet curable resin. Examples of the ultraviolet curable resin include: (meth)acrylic resin, polysilicone resin, polyester resin, urethane resin, amide resin, epoxy resin, and the like. To increase strength, hard coatings can contain additives. The additive is not limited, and examples thereof include inorganic fine particles, organic fine particles, and mixtures thereof.

When the front panel 50 is a glass plate, the glass plate is preferably tempered glass for displays. The thickness of the glass plate may be, for example, 10 μm or more and 1000 μm or less, or may be 10 μm or more and 800 μm or less. By using glass plates, front panels with excellent mechanical strength and surface hardness can be constructed.

The front panel 50 is preferably highly rigid, for example, the Young's modulus is above 70 GPa, and may be above 80 GPa. The Young's modulus of the front panel 50 is usually 100 GPa or less. Young's modulus can be determined by the following method. Use a super cutter to cut out a measurement sample of the front panel 50 with a long side of 110 mm and a short side of 10 mm. Next, the two ends of the above-mentioned measurement sample in the longitudinal direction were clamped with the upper and lower clamps of a tensile testing machine (Autograph AG-Xplus testing machine manufactured by Shimadzu Corporation) so that the distance between the clamps was 5 cm, and the temperature was In an environment of 23°C and relative humidity of 55%, pull the sample for measurement in the length direction at a pulling speed of 4mm/min, and calculate the temperature of 23°C from the slope of the straight line between 20 and 40MPa in the obtained stress-strain curve. , Young's modulus at relative humidity of 55%.

The image display element includes an image display panel, and may further include a touch sensor panel. A commonly known image display panel can be used, and examples thereof include organic EL panels. The organic EL display element 100 is an image display element including an organic EL panel. The touch sensor panel can be used with common The knower. When the image display element includes an image display panel and a touch sensor panel, the touch sensor panel and the image display panel are usually arranged in sequence from the circular polarizing plate side.

[Example]

The following are examples and comparative examples to illustrate the present invention more specifically, but the present invention is not limited to these examples.

[Measurement]

(1) Thickness of layer

The thickness of the adhesive layer was measured using a contact film thickness measuring device ("MS-5C" manufactured by Nikon Co., Ltd.). The linear polarizer and the alignment film were measured using a laser microscope ("OLS4100" manufactured by Olympus Co., Ltd.).

(2) Water vapor penetration

The water vapor transmittance W1 of the linear polarizing plate and the water vapor transmittance W2 of the retardation layer structure are measured by the moisture sensor method specified in JIS K 7129-1:2019. The temperature of the penetration unit was set to 40°C, the relative humidity of the high-humidity treatment chamber was set to 100%, and the relative humidity of the low-humidity treatment chamber was set to 10%.

(3)Phase difference characteristics

The phase difference characteristics were measured using "KOBRA-WPR" of Oji Scientific Instruments Co., Ltd.

(4) Measurement of monomer transmittance and visual sensitivity corrected polarization

The visual sensitivity correction unit transmittance and visual sensitivity correction polarization of the circular polarizing plate are made by making the linearly polarized light from the polarizer incident on the linear polarizing plate side of the circular polarizing plate, and passing it through an integrating sphere spectrometer (Japan). "V7100" manufactured by Spectrophotonics Co., Ltd.) was used for measurement. Calculate the MD transmittance and TD transmittance in the wavelength range from 380nm to 780nm, and calculate the monomer penetration at each wavelength according to formula (A) and formula (B) rate, polarization. Then, the visual sensitivity correction is performed using the 2-degree field of view (C light source) of JIS Z 8701, and the visual sensitivity corrected single unit transmittance (Ty) and the visual sensitivity corrected polarization degree (Py) are obtained. In addition, the so-called "MD transmittance" means the transmittance when the transmission axis of the polarizing plate sample is parallel to the direction of the polarized light emitted from the Glan-Thompson Prism. In formulas (A) and (B), "MD transmittance" is expressed as "MD". In addition, the so-called "TD transmittance" means the transmittance when the transmission axis of the polarizing plate sample is orthogonal to the direction of the polarized light emitted from the Glan-Thomson lens. In formula (A), formula In (B), "TD transmittance" is expressed as "TD".

Monomer penetration rate (%)=(MD+TD)/2 Formula (A)

Polarization degree (%)={(MD-TD)/MD+TD)}×100 Formula (B)

<Example 1>

(1) Production of linear polarizing plates

By dry stretching, a polyvinyl alcohol-based resin film with a thickness of 30 μm (average polymerization degree of about 2400, saponification degree of 99.9 mol% or more) is stretched uniaxially about 5 times in the longitudinal direction, and then immersed in a temperature-sensitive film while maintaining tension. Pure water at 60°C for 1 minute, and then immersed in an aqueous solution at 28°C with a mass ratio of iodine/potassium iodide/water of 0.05/5/100 for 60 seconds. Then, it was immersed in an aqueous solution with a temperature of 72°C and a mass ratio of potassium iodide/boric acid/water of 8.5/8.5/100 for 300 seconds. Then, it was washed with pure water at a temperature of 26° C. for 20 seconds, and then dried at a temperature of 65° C. to obtain a 12 μm-thick linear polarizer with iodine adsorbed and aligned on the polyvinyl alcohol-based resin film.

A polyvinyl alcohol aqueous solution was prepared by dissolving 3 parts by mass of carboxyl-modified polyvinyl alcohol ["KL-318" manufactured by Kuraray Co., Ltd.] with respect to 100 parts by mass of water. Water-soluble polyamide epoxy resin (Taoka Chemical Industry Co., Ltd.) was added at a ratio of 1.5 parts by mass to 100 parts by mass of water. "Sumirez Resin 650 (30)" manufactured by the company, solid content concentration 30% by mass) was mixed with the obtained aqueous solution to obtain a water-based adhesive.

The water-based adhesive obtained above was applied to one surface of the linear polarizer obtained above, and a cellulose triacetate film (hereinafter also referred to as "TAC film") with a thickness of 25 μm was laminated on the water-based adhesive layer. In addition, the other surface of the linear polarizer was coated with the aqueous adhesive obtained above, and a 32 μm thick hard coat (HC) layer of cellulose triacetate film was placed with the TAC film side in contact with the aqueous adhesive layer. (hereinafter also referred to as "HC-TAC film") is laminated on the water-based adhesive layer. The obtained laminate was dried at a temperature of 80° C. for 5 minutes, thereby obtaining a linear polarizing plate having protective films on both sides of the linear polarizing plate. The layer structure of the linear polarizer is HC-TAC film/water-based adhesive layer/linear polarizer/water-based adhesive layer/TAC film.

The water vapor transmittance W1 of the obtained linear polarizing plate was measured, and the result was 45 [g/(m ² .24hr)].

(2) Preparation of phase difference layer structure

An alignment film is formed on a first base material layer made of a transparent resin, and a liquid crystal layer forming composition containing a rod-shaped nematic polymerizable liquid crystal compound is applied to prepare a first base material layer with the first base material layer. Phase difference layer. The first phase difference layer is a λ/4 layer. The thickness of the first retardation layer is 1 μm. The wavelength dispersion α [in-plane phase difference value Re(450)/in-plane phase difference value Re(550)] of the first phase difference layer is 0.87, and Re(550) is 142 nm.

In addition, the second retardation layer with the second base material layer is produced by the following method. First, 10.0 parts by mass of polyethylene glycol di(meth)acrylate, 10.0 parts by mass of trimethylolpropane triacrylate, 10.0 parts by mass of 1,6-hexanediol di(meth)acrylate, and as light 1.50 parts by mass of Irgacure 907, a polymerization initiator, was dissolved in 70.0 parts by mass of methyl ethyl ketone, which is a solvent, and an alignment film was prepared to form Use composition. Next, 20.0 parts by mass of the photopolymerizable nematic liquid crystal compound and 1.0 part by mass of Irgacure 907 as a photopolymerization initiator were dissolved in 80.0 parts by mass of propylene glycol monomethyl ether acetate as a solvent to prepare a liquid crystal layer. Use composition.

Corona treatment is performed on one side of the second base material layer, and the prepared composition for forming an alignment film is coated on the corona-treated surface using a rod coater. After heat-treating the coating layer at a temperature of 80° C. for 60 seconds, the coating layer was irradiated with ultraviolet rays to polymerize and cure the alignment film forming composition, thereby forming an alignment film with a thickness of 1.8 μm on the second base material layer. The liquid crystal layer forming composition prepared above is coated on the alignment film. After heat-treating the coating layer at a temperature of 80° C. for 60 seconds, the coating layer was irradiated with ultraviolet rays to polymerize and cure the liquid crystal layer forming composition, thereby forming a liquid crystal cured layer with a thickness of 0.7 μm on the alignment film. Through the above operation, the second retardation layer with the second base material layer is obtained. The thickness direction retardation value Rth of the second retardation layer is -75 nm.

Mix the cationic curable ingredients shown below to prepare an ultraviolet curable adhesive.

3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Co., Ltd.): 70 parts by mass

Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase Chemtex Co., Ltd.): 20 parts by mass

2-Ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase Chemtex Co., Ltd.): 10 parts by mass

Cationic polymerization initiator (trade name: CPI-100, 50% solution, manufactured by San Apro Co., Ltd.): 4.5 parts by mass (substantial solid content: 2.25 parts by mass)

1,4-diethoxynaphthalene: 2.0 parts by mass

Corona treatment is performed on the retardation layer side of the first retardation layer with the first base material layer and the retardation layer side of the second retardation layer with the second base material layer, respectively. The ultraviolet curable adhesive prepared above is coated on a corona-treated surface, and the first retardation layer with the first base material layer and the second retardation layer with the second base material layer are bonded together. Ultraviolet rays are irradiated from the second base material layer side to harden the ultraviolet curable adhesive, thereby forming an adhesive layer. The thickness of the ultraviolet curable adhesive layer after curing is 1.5 μm.

From the bonded body of the first retardation layer with the first base material layer and the second retardation layer with the second base material layer, the first base material layer and the second base material layer are peeled and removed to obtain the retardation layer. Structure. The layer structure of the retardation layer structure is alignment film/first retardation layer/ultraviolet curable adhesive layer/second retardation layer/alignment film.

The water vapor permeability W2 of the obtained retardation layer structure was measured, and the result was 600 [g/(m ² .24hr)].

(3) Preparation of the adhesive composition for the first adhesive layer

(3-1) Production of acrylic resin

Butyl acrylate (BA), methyl acrylate (MA), and 2-phenoxyethyl acrylate (PEA) were mixed so as to have the monomer composition shown in Table 1 (the total amount of monomers is 100 parts by mass). , 2-hydroxyethyl acrylate (HEA) and acrylic acid (AA) were put into a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, and 100 parts by mass of ethyl acetate was put into the reaction vessel for dilution to form Monomer mixture. After replacing the air in the reaction vessel with nitrogen to exhaust oxygen, the internal temperature was raised to 55°C, and then the entire amount of 0.12 parts by mass of azobisisobutyronitrile as a polymerization initiator was dissolved in 10 mass of ethyl acetate. portion of the solution. After adding the polymerization initiator, the internal temperature of the reaction vessel was maintained at 55°C for 1 hour. Then, while maintaining the internal temperature at 54 to 56°C, ethyl acetate was continuously added to the reaction vessel, and acrylic acid was added to the reaction vessel. The addition of ethyl acetate was stopped when the concentration of the resin reached 35% by mass, and then the The temperature was maintained at this temperature until 12 hours elapsed from the addition of ethyl acid ester. Finally, ethyl acetate was added to adjust the concentration of the acrylic resin to 20% by mass, and an ethyl acetate solution of the acrylic resin was prepared.

The standard polystyrene-converted weight average molecular weight Mw and molecular weight distribution [weight average molecular weight Mw/number average molecular weight] of the obtained acrylic resin measured by gel permeation chromatography (GPC: Gel Permeation Chromatography) Mn] are shown together in Table 1.

[Table 1]

(3-2) Preparation of adhesive composition

Mixed with 100 parts by mass of the solid content of the acrylic resin obtained in the above (3-1): an ethyl acetate solution (solid content) of the trimethylolpropane adduct of toluene diisocyanate as a cross-linking agent Concentration 75% by mass, Coronate L, manufactured by Tosoh Co., Ltd.) 0.5 parts by mass, 0.5 parts by mass of 3-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) as a silane compound , and 3 parts by mass of N-octyl-4-methylpyridinium hexafluorophosphate as an ionic compound as an antistatic agent, and then ethyl acetate was added so that the solid concentration of the acrylic resin became 15% by mass. , and prepare the adhesive composition. The compounding amount (mass parts) of the cross-linking agent is the solid part conversion amount.

(4) Preparation of the second adhesive layer

Preparation: A 15 μm-thick adhesive layer composed of an adhesive composition containing (meth)acrylic resin and containing no antistatic agent is used as the second adhesive layer.

(5) Production of circular polarizing plates

The adhesive composition for the first adhesive layer containing an antistatic agent prepared in the above (3) is coated on the surface of the TAC film side of the linear polarizing plate obtained in the above (1). Then, the surface of the linear polarizing plate coated with the adhesive composition for the first adhesive layer is bonded to the retardation layer structure obtained in the above (2) through the first base material layer. The peeling removes the exposed alignment film. Then, the adhesive layer containing no antistatic agent prepared in the above (4) is bonded to the surface of the alignment film on the second phase difference layer side of the retardation layer structure, and dried to obtain circularly polarized light. plate. The layer structure of the circular polarizing plate is HC-TAC film/water-based adhesive layer/linear polarizer/water-based adhesive layer/TAC film/adhesive layer containing antistatic agent (first adhesive layer)/alignment film/first Retardation layer/ultraviolet curable adhesive layer/second retardation layer/alignment film/adhesive layer that does not contain antistatic agent (second adhesive layer). The thicknesses of the first adhesive layer and the second adhesive layer formed after lamination and drying are 20 μm and 15 μm respectively.

(6) Humid heat durability test of circularly polarizing plates

The following wet heat durability test was performed on the circularly polarizing plate obtained in the above (5). First, cut the circular polarizing plate into a square of 30mm×30mm. At this time, the linear polarizer is cut so that the absorption axis is parallel to the side of the square. The cut circular polarizing plate was bonded to 40mm×40mm alkali-free glass ("EAGLE A resin-based adhesive layer (excluding antistatic agent) was bonded to a 40 mm × 40 mm alkali-free glass ("EAGLE XG" manufactured by Corning Corporation) on a linear polarizing plate of a circular polarizing plate to prepare a sample for evaluation. For this evaluation sample, the in-plane phase difference value [Re(550)] at a wavelength of 550 nm, the visual sensitivity-corrected single unit transmittance Ty, and the visual sensitivity-corrected polarization degree Py were measured.

Next, the evaluation sample was subjected to a moist heat durability test stored at a temperature of 65°C and a relative humidity of 90% RH for 336 hours. The evaluation sample after the test was then used to measure Re (550), visual sensitivity correction monomer penetration The rate Ty and visual sensitivity correct the polarization degree Py. Find the values before and after the wet heat durability test The absolute value △Re of the difference in Re (550), the absolute value △Ty of the difference in visual sensitivity corrected monomer transmittance Ty, and the absolute value △Py of the difference in visual sensitivity corrected polarization Py are determined in accordance with the following standards Make an assessment. The results are shown in Table 2.

[△Re]

E: 0.5nm or less.

G: 1.0nm or less.

F: More than 1.0nm.

[△Ty and △Py]

E: 1.0% or less.

G: More than 1.0% and less than 3.0%.

F: More than 3.0%.

<Example 2>

(1) Production of linear polarizing plates

A polyvinyl alcohol film with an average degree of polymerization of about 2400, a saponification degree of 99.9 mol% or more, and a thickness of 20 μm is immersed in pure water at 30°C, and then immersed in iodine:potassium iodide:water at a mass ratio of 0.02:2 at 30°C. : 100 aqueous solution for iodine staining (hereinafter also referred to as the iodine staining step). The polyvinyl alcohol film after the iodine dyeing step was immersed in an aqueous solution with a mass ratio of potassium iodide: boric acid: water of 12:5:100 at 56.5°C to perform boric acid treatment (hereinafter also referred to as the boric acid treatment step). After washing the polyvinyl alcohol film after the boric acid treatment step with pure water at 8°C, it was dried at 65°C to obtain a linear polarizer (thickness after stretching: 8 μm) with iodine adsorbed and aligned on polyvinyl alcohol. At this time, extension is performed in the iodine staining step and the boric acid treatment step. The total stretch ratio in this stretch is 5.3 times.

On one side of the linear polarizer obtained above, the same water-based adhesive as in Example 1 was coated, and the cyclic olefin resin film with a thickness of 29 μm was attached with the HC layer so that the COP film side was in contact with the water-based adhesive layer. (hereinafter also referred to as "HC-COP film") is laminated on the water-based adhesive layer. The obtained laminate was dried at a temperature of 80° C. for 5 minutes, thereby obtaining a linear polarizing plate having a protective film on one surface of the linear polarizing plate. The layer structure of the linear polarizer is HC-COP film/water-based adhesive layer/linear polarizer.

(2) Production of circular polarizing plates

Except for using the linear polarizing plate produced in the above (1), a circular polarizing plate was produced in the same manner as in Example 1, and a wet heat durability test was performed. The results are shown in Table 2. The layer structure of the circular polarizer is HC-COP film/water-based adhesive layer/linear polarizer/adhesive layer containing antistatic agent (first adhesive layer)/alignment film/first retardation layer/ultraviolet curable adhesive Agent layer/second retardation layer/alignment film/adhesive layer without antistatic agent (second adhesive layer). Table 2 shows the water vapor transmittance W1 of the linear polarizing plate and the water vapor transmittance W2 of the retardation layer structure together.

<Example 3>

In addition to using the adhesive composition obtained by the following preparation method as the adhesive composition (containing an antistatic agent) for the first adhesive layer for bonding the linear polarizing plate and the retardation layer structure, other A circularly polarizing plate was produced in the same manner as in Example 2, and a wet heat durability test was performed. The results are shown in Table 2. The layer structure of the circularly polarizing plate is the same as that of Example 2. Table 2 shows the water vapor transmittance W1 of the linear polarizing plate and the water vapor transmittance W2 of the retardation layer structure together.

(Preparation of the adhesive composition for the first adhesive layer)

As a solvent, 190 parts by mass of ethyl acetate, 70.0 parts by mass of butyl acrylate, 10.0 parts by mass of methyl acrylate, 16.0 parts by mass of 2-phenoxyethyl acrylate, and 4.0 parts by mass of 2-hydroxyethyl acrylate The mixed solution is put into a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer. While replacing the air in the device with nitrogen to exhaust oxygen, the internal temperature is raised to 55°C. Then, a solution in which 0.15 parts by mass of azobisisobutyronitrile, which is a polymerization initiator, was dissolved in 10 parts by mass of ethyl acetate was added in full. Keep warm for 10 hours at an internal temperature of 54 to 56°C. Finally, ethyl acetate was added to the reaction container so that the concentration of the acrylic resin would be 20% by mass.

Mixed with 100 parts by mass of the solid content of the acrylic resin obtained above: cross-linking agent (trimethylolpropane adduct of xylene diisocyanate, trade name "Takenate D110N", manufactured by Mitsui Chemicals Co., Ltd.) 0.3 Parts by mass, 0.5 parts by mass of a silane-based compound (KBM-403: Glycidoxypropyltrimethoxysilane (liquid), manufactured by Shin-Etsu Chemical Industry Co., Ltd.), and an ionic compound (N-decyl) as an antistatic agent 1.5 parts by mass of pyridinium bis(fluorosulfonyl)imide), and then ethyl acetate was added so that the solid concentration of the acrylic resin became 14% by mass, thereby obtaining an adhesive composition.

<Comparative example 1>

An adhesive layer with a thickness of 5 μm (excluding antistatic agent) composed of an adhesive composition containing (meth)acrylic resin was used as the first adhesive layer. The adhesive composition used in Example 1 was used as the first adhesive layer. An adhesive layer (containing an antistatic agent) with a thickness of 20 μm (the adhesive composition used as the first adhesive layer in Example 1) was used as the second adhesive layer. In addition, the other A circularly polarizing plate was produced in the same manner as in Example 1, and a wet heat durability test was performed. The results are shown in Table 2.

<Comparative example 2>

In the adhesive composition constituting the second adhesive layer, the mixing amount of N-octyl-4-methylpyridinium phosphorus hexafluoride as an ionic compound is changed from 3 parts by mass to 6 parts by mass. , otherwise the same as Comparative Example 1 to prepare a circular polarizing plate, and perform a wet heat durability test. The results are shown in Table 2.

<Comparative example 3>

In addition to using the adhesive layer (containing an antistatic agent) composed of the adhesive composition used in Example 3 (the adhesive composition for the first adhesive layer in Example 3) as the second adhesive layer, Except for the agent layer (thickness: 20 μm), a circularly polarizing plate was produced in the same manner as Comparative Example 1, and a wet heat durability test was performed. The results are shown in Table 2.

<Example 4>

(1) Preparation of phase difference layer structure

From the bonded body of the first retardation layer with the first base material layer and the second retardation layer with the second base material layer obtained in Example 1, the second base material layer was peeled and removed. A TAC film (HC-TAC film) having a HC layer with a thickness of 25 μm was prepared, and this film was bonded to the second retardation layer of the bonded body via a (meth)acrylic resin-based adhesive layer with a thickness of 5 μm. side. Then, the first base material layer is peeled and removed to obtain a retardation layer structure. The layer structure of the retardation layer structure is alignment film/first retardation layer/ultraviolet curable adhesive layer/second retardation layer/alignment film/adhesive layer/HC-TAC film.

(2) Production of circular polarizing plates

Except using the retardation layer structure obtained in the above (1), a circularly polarizing plate was produced in the same manner as in Example 1, and a wet heat durability test was performed. The results are shown in Table 2. The layer structure of the circular polarizing plate is HC-TAC film/water-based adhesive layer/linear polarizer/water-based adhesive layer/TAC film/adhesive layer containing antistatic agent (first adhesive layer)/alignment film/first Retardation layer/UV curable adhesive layer/2nd retardation layer/alignment film/adhesive layer/HC-TAC film.

Regarding Comparative Examples 1 to 3 and Example 4, Table 2 shows the water vapor transmittance W1 of the linear polarizing plate and the water vapor transmittance W2 of the retardation layer structure together.

[Table 2]

1: Linear polarizing plate

2: Phase difference layer structure

10: 1st adhesive layer

Claims (9)

A circular polarizing plate for organic EL display devices, The system includes in order: a linear polarizing plate, a first adhesive layer, and a retardation layer structure including at least one retardation layer. The first adhesive layer contains an antistatic agent. A circular polarizing plate, which includes in order: a linear polarizing plate, a first adhesive layer, a phase difference layer structure including at least one phase difference layer, and a second adhesive layer, Among the first adhesive layer and the second adhesive layer, only the first adhesive layer contains an antistatic agent. The circular polarizing plate according to claim 1 or 2, wherein the water content of the linear polarizing plate at a temperature of 40°C is measured by the moisture sensor method specified in JIS K 7129-1:2019. When the vapor permeability is W1 and the water vapor permeability of the retardation layer structure is W2, W1 is 5 [g/(m ² .24hr)] or more and 100 [g/(m ² .24hr)] or less, W2 is 300 [g/(m ² .24hr)] or more and 900 [g/(m ² .24hr)] or less. The circular polarizing plate according to any one of claims 1 to 3, wherein the straight line measured at a temperature of 40° C. by the moisture sensor method specified in JIS K 7129-1:2019 When the water vapor transmittance of the polarizing plate is W1 and the water vapor transmittance of the retardation layer structure is W2, W1/W2 is 0.006 or more and 0.4 or less. The circularly polarizing plate according to any one of claims 1 to 4, wherein the content of the antistatic agent is 0.5 to 5 parts by mass relative to 100 parts by mass of the resin contained in the first adhesive layer. The circularly polarizing plate according to any one of claims 1 to 5, wherein the antistatic agent is an ionic compound. The circularly polarizing plate according to any one of claims 1 to 6, wherein the retardation layer is a liquid crystal hardened layer. The circular polarizing plate according to any one of claims 1 to 7, wherein the linear polarizing plate includes: a linear polarizing plate, and a protective film laminated on one or both sides of the linear polarizing plate. An organic EL display device includes the circular polarizing plate described in any one of claims 1 to 8.

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