TWI820171B - Circular polarizing plate and image display device using the same - Google Patents

Abstract

Provided is a circular polarizing plate containing a polarizing film and a retardation film functioning as λ/4 plate, wherein the angel formed by the absorption axis of the polarizing film and the retardation axis of the retardation film is 35°~55°, the retardation film includes liquid crystal material, and the retardation film satisfies the following equations (α) and (β)，

Re(450)/Re(550)≦1.00 (α)

1.00≦Re(650)/Re(550) (β)

The retardation film includes impurities, the thickness of the retardation film is 1.5μm or more, and the surface of the retardation film is substantially flat.

Description

Circular polarizing plate and image display device using the same

The present invention relates to a circularly polarizing plate and an image display device using the circularly polarizing plate.

In recent years, with the popularization of mobile phones, tablet terminals, etc., liquid crystal display devices or organic electroluminescence display devices (organic EL display devices) have become widely used as image display devices. In an organic EL display device, in order to prevent external light from appearing as a mirror when reflected by a metal electrode (cathode) for visual recognition, a circular polarizing plate is installed on the visible side surface of the organic EL panel. Furthermore, there is a demand in the market for display devices to be thinner. Therefore, in a display device that requires thinning, each component used in the display device, such as a polarizing plate or a circular polarizing plate, is preferably also thin.

The circularly polarizing plate generally uses a laminate of a polarizing plate and a λ/4 plate. For example, a circularly polarizing plate is known in which a polarizing film and a retardation layer having specific refractive index characteristics are laminated (see, for example, Patent Document 1).

The retardation film is generally a stretched film produced by stretching a resin film, and a λ/4 plate using this stretched film has a limit in thinning. Therefore, in order to further reduce the thickness, a λ/4 plate using a layer hardened with a polymerizable liquid crystal compound has been proposed (for example, see Patent Document 2). However, in a circularly polarizing plate with such a λ/4 plate, foreign matter will be mixed in during the manufacturing process. This foreign matter (this problem does not occur in the λ/4 plate made of a resin film) will cause As a bright spot, it will have a negative impact on the display characteristics. In addition, there may be a problem of reduced manufacturing productivity. Such an influence is even greater in a circular polarizing plate using a λ/4 plate hardened with a layer of a polymerizable liquid crystal compound with a phase difference value that has reverse wavelength dispersive properties. The reason is that a wider range of wavelengths achieves anti-reflection effects, so the bright spots tend to be easier to visually identify.

[Prior technical literature] [Patent Document]

Patent Document 1: Japanese Patent No. 3325560.

Patent Document 2: Japanese Patent Application Publication No. 2014-123134.

The present invention was developed to solve the aforementioned conventional problems, and its main purpose is to provide a circularly polarizing plate that is very thin, has excellent anti-reflection properties, and suppresses the adverse effects of foreign matter on the display performance of an image display device.

That is, the present invention provides the following circularly polarizing plate and image display device.

[1] A circularly polarizing plate, which is provided with a polarizing film and a retardation film functioning as a λ/4 plate in this order, and the angle between the absorption axis of the polarizing film and the slow axis of the retardation film is 35° to 55°. ,

The aforementioned retardation film contains liquid crystal material,

The aforementioned retardation film satisfies the following formulas (α) and (β),

Re(450)/Re(550)≦1.00 (α)

1.00≦Re(650)/Re(550) (β)

The aforementioned retardation film contains foreign matter,

The thickness of the aforementioned retardation film is 1.5 μm or more,

The surface of the retardation film is substantially flat.

[In the formula, Re(450) represents the in-plane phase difference value at a wavelength of 450 nm, Re(550) represents the in-plane phase difference value at a wavelength of 550 nm, and Re(650) represents the in-plane phase difference value at a wavelength of 650 nm. ]

[2] The circular polarizing plate according to [1], wherein the foreign matter is brush scraps.

[3] A laminated body including the circular polarizing plate according to [1] or [2], and a touch sensor.

[4] An image display device having the circular polarizing plate according to [1] or [2].

[5] An image display device having the laminated body according to [3].

[6] The image display device according to [4] or [5], wherein the image display device is an organic electroluminescence display device.

According to the present invention, a circular polarizing plate can be obtained, which is very thin, has excellent anti-reflection properties, and suppresses the adverse effects of foreign matter on the display performance of the image display device.

Preferred embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)

The definitions of terms and symbols in this manual are as follows.

(1)Refractive index (nx, ny, nz)

"nx" is the refractive index in the direction of maximum in-plane refractive index (that is, the slow axis direction), "ny" is the direction orthogonal to the slow axis in the plane, and "nz" is the refractive index in the thickness direction.

(2) In-plane phase difference value

The in-plane phase difference value (Re(λ)) is the in-plane phase difference value of the film at a temperature of 23°C and a wavelength λ (nm). Re(λ) is obtained by Re(λ)=(nx-ny)×d when the film thickness is d(nm).

(3) Phase difference in thickness direction

The in-plane retardation value (Rth(λ)) is the retardation value in the film thickness direction at a temperature of 23°C and a wavelength λ (nm). Rth(λ) is obtained by Rth(λ)=((nx+ny)/2-nz)×d when the film thickness is d(nm).

(Polarizing film)

The polarizing film is not particularly limited, and various polarizing films can be used. Examples of polarizing films include dichroic films in which iodine or dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and ethylene/vinyl acetate copolymer-based partially saponified films. Polyene-based alignment films such as polyethylene-based alignment films that are uniaxially stretched (dyed) and uniaxially stretched, such as dehydrated polyvinyl alcohol or dehydrochloric acid-treated polyvinyl chloride. Among them, a polarizing film composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferred. The film thickness of these polarizing films is not particularly limited, but is generally about 3 to 80 μm. The polarizing film used in a display device required to be thinner preferably has a film thickness of 15 μm or less.

The polyvinyl alcohol-based film can be made of saponified polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include, in addition to polyvinyl acetate, which is a vinyl acetate homopolymer, copolymers with other monomers copolymerizable with vinyl acetate, and the like. Other monomers that can be copolymerized with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamide having an ammonium group.

The saponification degree of polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin can be modified. For example, polyvinyl alcohol modified with aldehydes can be used. Formal or polyvinyl acetal, etc. In addition, the degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

Films made from polyvinyl alcohol-based resins are used as raw materials for polarizing films. The polyvinyl alcohol-based resin film can be formed by a known method. When considering that the thickness of the polarizing film obtained is 15 μm or less, the film thickness of the raw material film of the polyvinyl alcohol resin is preferably about 5 to 35 μm, more preferably 5 to 20 μm. If the film thickness of the raw material film exceeds 35 μm, the stretching ratio when producing the polarizing film needs to be increased, and the resulting polarizing film tends to shrink in size. On the other hand, if the film thickness of the raw material film is less than 5 μm, the handleability during stretching is reduced, and defects such as cutting during production tend to easily occur.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, at the same time as, or after dyeing with the dichroic dye. When uniaxial extension is performed after dyeing, the uniaxial extension can be performed before or during boric acid treatment. Furthermore, uniaxial stretching can be performed in a plurality of stages. The role of this boric acid treatment is to cross-link the dyed polyvinyl alcohol-based resin film.

In uniaxial stretching, uniaxial stretching can be performed between rollers with different peripheral speeds, or uniaxial stretching can be performed using hot rollers. In addition, the uniaxial stretching may be dry stretching in which the polyvinyl alcohol-based resin film is stretched in the atmosphere or wet stretching in which the polyvinyl alcohol-based resin film is swollen in a solvent (for example, water). The extension ratio is usually about 3 to 8 times.

A method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye is, for example, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. Specifically, iodine or a dichroic dye is used as a dichroic dye. In addition, the polyvinyl alcohol-based resin film is preferably immersed in water before dyeing.

When iodine is used as a dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide and dyeing is usually used. In this aqueous solution, the iodine content is usually per 100 parts by weight of water. It is about 0.01 to 1 part by weight. In addition, the potassium iodide content is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually around 20 to 40°C.

In addition, the aqueous solution immersion time (dyeing time) is usually about 20 to 1,800 seconds.

On the other hand, when a dichroic dye is used as a dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye and dyeing is generally used. In the aqueous solution, the dichroic dye content is usually about 1×10 ^-4 to 10 parts by weight per 100 parts by weight of water, preferably about 1×10 ^-3 to 1 part by weight. The aqueous solution may contain inorganic salts such as sodium sulfate as dyeing auxiliaries. The temperature of the dichroic dye aqueous solution used for dyeing is usually around 20 to 80°C. In addition, the immersion time (dying time) in the aqueous solution is usually about 10 to 1,800 seconds.

Boric acid treatment after dyeing with a dichroic dye can usually be performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid.

In the aqueous solution containing boric acid, the amount of boric acid is usually about 2 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. In an aqueous solution containing boric acid, the amount of potassium iodide is usually about 0.1 to 15 parts by weight per 100 parts by weight of water, preferably about 5 to 12 parts by weight. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually above 50°C, preferably 50 to 85°C, more preferably 60 to 80°C.

The polyvinyl alcohol-based resin film treated with boric acid is usually washed with water. The water washing treatment can be performed, for example, by immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing process is usually around 5 to 40°C. In addition, the immersion time is usually about 1 to 120 seconds.

After washing with water, drying is performed to obtain a polarizing film. Drying can be done using a hot air dryer or far infrared heater. The drying treatment temperature is usually about 30 to 100°C, preferably 50 to 80°C. The drying treatment time is usually about 60 to 600 seconds, preferably 120 to 600 seconds.

The moisture content of the polarizing film can be reduced to a practical level through drying treatment. Its moisture content is usually 5 to 20% by weight, preferably 8 to 15% by weight. If the moisture content is less than 5% by weight, the polarizing film will lose flexibility, and the polarizing film may be damaged or cracked after drying. In addition, if the moisture content is higher than 20% by weight, the thermal stability of the polarizing film may be poor.

In addition, in the polarizing film manufacturing process, the stretching, dyeing, boric acid treatment, water washing step, and drying step of the polyvinyl alcohol-based resin film can be performed according to the method described in Japanese Patent Application Laid-Open No. 2012-159778, for example. In the method described in this document, a polyvinyl alcohol-based resin layer that serves as a polarizing film is formed by coating a base film with a polyvinyl alcohol-based resin.

As mentioned above, the thickness of the polarizing film is preferably 15 μm or less, more preferably 3 to 10 μm.

Furthermore, the polarizing film can be used as a single-sided protective polarizing plate having a protective film on only one side of the polarizing film, or as a double-sided protective polarizing plate having protective films on both sides of the polarizing film.

The polarizing film may be a liquid crystal-coated polarizing film coated with a composition containing a liquid crystal compound. The composition containing a liquid crystal compound may contain a liquid crystal compound and a dichroic pigment. The liquid crystal compound only needs to have the property of displaying a liquid crystal state, and it is particularly preferable because it has a higher alignment state such as a smectic phase and can exhibit high polarizing properties. Furthermore, the liquid crystal compound preferably has a polymerizable functional group. The dichroic dye is a liquid crystal compound and is a dye showing dichroism in alignment. The dichroic dye itself may have liquid crystallinity or may have a polymerizable functional group. Any compound in the composition containing the liquid crystal compound has a polymerizable functional group. The composition containing the liquid crystal compound may further contain a initiator, solvent, dispersant, leveling agent, stabilizer, surfactant, cross-linking agent, silane coupling agent, etc. By coating a composition containing a liquid crystal compound on the alignment film The liquid crystal coating type polarizing film can be produced by forming the object and hardening it. Compared with a film-type polarizing film (a polarizing film formed of a polyvinyl alcohol-based resin film), the liquid crystal coating type polarizing film can be formed to be thinner. The thickness of the liquid crystal coating type polarizing film is 0.5 to 5 μm, preferably 1 to 4 μm.

(protective film)

The material for forming the protective film provided on one or both sides of the polarizing film is preferably one that is excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropic properties, and the like. Examples include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as cellulose diacetate and cellulose triacetate, and acrylic polymers such as polymethyl methacrylate. Polymers, styrenic polymers such as polystyrene or acrylonitrile/styrene copolymer (AS resin), polycarbonate polymers, etc. Examples of polymers that form the protective film include polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, polyolefin polymers such as ethylene/propylene copolymers, and vinyl chloride polymers. , amide polymers such as nylon or aromatic polyamide, amide imine polymers, polyamide polymers, polyether polyamide polymers, polyether ether ketone polymers, polyphenylene sulfide polymers , vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, aryl ester polymers, polyoxymethylene polymers, epoxy polymers, or mixtures of the foregoing polymers. The protective film can be formed as a cured layer of thermosetting or ultraviolet curing resin such as acrylic, urethane, acrylic urethane, epoxy, and polysiloxane. When protective films are provided on both sides of the polarizing film, protective films made of the same polymer material can be used on both sides, or protective films made of different polymer materials can be used.

The thickness of the protective film is generally about 1 to 100 μm from the viewpoint of operability such as strength or handleability, and film properties. Preferably it is 5 to 80 micrometers, More preferably, it is 5 to 50 micrometers.

The polarizing film and the protective film are usually laminated via a water-based adhesive or the like. Examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, Water-based polyurethane, water-based polyester, etc. In addition to the above, examples of the adhesive between the polarizing film and the protective film include ultraviolet curing adhesives, electron beam curing adhesives, and the like. The electron beam curable adhesive shows better adhesion than the various protective films mentioned above. The protective film and the polarizing film are preferably subjected to saponification treatment, corona treatment, plasma treatment, etc. before being bonded to the polarizing film.

On the non-polarizing film-adhering surface of the aforementioned protective film, a hard coating or anti-reflective treatment, an antistatic layer or an anti-adhesion layer, or treatment for the purpose of diffusion or anti-glare can be implemented.

Among polarizing films, the protective film used on the side without a retardation film may be subjected to processing that can improve visual visibility when viewed through polarized sunglasses (typically, imparting circular polarization (or elliptical polarization) function, imparting super high phase difference). By implementing such processing, excellent visibility can be achieved even when the display screen is viewed through polarized lenses such as polarized sunglasses. Therefore, the circular polarizing plate can be applied to image display devices that can be used outdoors.

In addition, the protective film used between the polarizing film and the retardation film is preferably optically isotropic. "Optical isotropy" in this specification means that Re (550) is 0 nm to 10 nm, and Rth (550) is -20 nm to +20 nm.

(Retardation film functioning as a λ/4 plate)

The retardation film containing a liquid crystal material used in the present invention can function as a so-called λ/4 plate. The in-plane phase difference value Re (550) of the retardation film at a wavelength of 550 nm is 90 to 190 nm, preferably 110 to 170 nm, and more preferably 120 to 160 nm.

The retardation film system contains a liquid crystal material. The concept of containing a liquid crystal material is that the liquid crystal material contains one capable of forming a liquid crystal layer, or a cured product using a liquid crystal material and cured by a polymerization reaction or the like while the liquid crystal material is in a liquid crystal state. Compared with non-liquid crystal materials, the difference between nx and ny of the obtained retardation layer can be greatly increased by using liquid crystal materials. As a result, the phase of the desired in-plane phase difference value is obtained The thickness of the differential layer can be significantly reduced, and the obtained circular polarizing plate can contribute to the thinning of image display devices. In addition, the roll-to-roll method can be used in the manufacturing of circularly polarizing plates, which can significantly shorten the manufacturing steps. Details are described later.

The liquid crystal material is preferably one in which the liquid crystal phase can form a nematic phase (nematic liquid crystal). The liquid crystal display mechanism of the liquid crystal material can be lyotropic or thermal. The preferred alignment state of the liquid crystal material is homogeneous alignment. Liquid crystal materials can be used alone or in combination.

The retardation film is preferably a hardened layer of liquid crystal material. Specifically, the liquid crystal material is preferably a polymerizable monomer and/or a crosslinkable monomer. Hereinafter, the liquid crystal material of this polymerizable monomer or crosslinkable monomer is called "polymerizable liquid crystal". By polymerizing or crosslinking the polymerizable liquid crystal, the polymerizable liquid crystal can be fixed. After aligning the polymerizable liquid crystal, for example, the polymerizable liquid crystal is polymerized or cross-linked, thereby fixing the alignment state. Here, a polymer is formed by polymerization and a three-dimensional network structure is formed by cross-linking, but these are non-liquid crystalline. Therefore, the formed retardation film does not undergo transition into a liquid crystal phase, a glass phase, and a crystal phase with temperature changes that are unique to liquid crystal compounds called polymeric liquid crystals. As a result, the obtained retardation film is not affected by temperature changes and can form a layer with extremely excellent stability.

In order for a layer formed by polymerizing polymerizable liquid crystal to exhibit an in-plane phase difference, the polymerizable liquid crystal only needs to be aligned in an appropriate direction. When the polymerizable liquid crystal is rod-shaped, the optical axis of the polymerizable liquid crystal is aligned horizontally with respect to the plane of the substrate, thereby exhibiting an in-plane phase difference. At this time, the optical axis direction is consistent with the slow axis direction. When the polymerizable liquid crystal is disk-shaped, the optical axis of the polymerizable liquid crystal is aligned horizontally with respect to the plane of the substrate, thereby exhibiting an in-plane phase difference. At this time, the optical axis is orthogonal to the slow axis. The alignment state of the polymerizable liquid crystal can be adjusted by using an appropriate alignment film and by combining the alignment film with the polymerizable liquid crystal.

In the present invention, a retardation film having optical characteristics represented by formula (α) and formula (β) can be obtained by using a cured layer of the following polymerizable liquid crystal. In order to exhibit such optical characteristics, two or more phase difference elements can be stacked The film serves as the retardation film of the circularly polarizing plate of the present invention. When using two or more retardation films, it is sufficient that at least one of the retardation films contains a liquid crystal material.

Re(450)/Re(550)≦1.00 (α)

1.00≦Re(650)/Re(550) (β)

Re(450)/Re(550) is preferably 0.95 or less, and may be 0.90 or less. Re(650)/Re(550) preferably exceeds 1.00.

<Polymerizable liquid crystal>

As mentioned above, polymerizable liquid crystal is a liquid crystal material having a polymerizable group. The polymerizable group refers to a group related to the polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group involved in the polymerization reaction through active radicals or acids generated by the photopolymerization initiator described below. Examples of the polymerizable group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloxy, oxirane, and oxyethyl. Heterocyclobutyl (oxetanyl), etc. Among them, acryloxy group, methacryloxy group, vinyloxy group, oxirane group and oxetanyl group are preferred, and acryloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal may be thermotropic liquid crystal or lyotropic liquid crystal. If thermotropic liquid crystals are classified according to regularity, they can be nematic liquid crystals or smectic liquid crystals.

For example, in order to exhibit better optical properties, the polymerizable liquid crystal used in the present invention is a compound represented by the following formula (1) (hereinafter referred to as "compound (1)").

P ¹ -F ¹ -(B ¹ -A ¹ ) _k -E ¹ -G ¹ -D ¹ -Ar-D ² -G ² -E ² -(A ² -B ² ) _l -F ² -P ² ( 1)

[In formula (1), Ar represents a divalent group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The number of π electrons N _π contained in the aromatic ring in the Ar group is 12 and above.

D ¹ and D ² independently represent *-O-CO- (* represents the position bonded to Ar), *-C(=S)-O-, *-OC(=S)-, *-CR ¹ R ² -, *-CR ¹ R ² -CR ³ R ⁴ -, *-O-CR ¹ R ² -, *-CR ¹ R ² -O-, *-CR ¹ R ² -O-CR ³ R ⁴ - , *-CR ¹ R ² -O-CO-, *-O-CO-CR ¹ R ² -, *-CR ¹ R ² -O-CO-R ³ R ⁴ -, *-CR ¹ R ² -CO -O-CR ³ R ⁴ -, *-NR ¹ -CR ² R ³ -, *-CR ² R ³ -NR ¹ -, *-CO-NR ¹ -, or *-NR ¹ -CO-. R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.

G ¹ and G ² each independently represent a divalent alicyclic hydrocarbon group. The hydrogen atoms contained in the alicyclic hydrocarbon group may be substituted by halogen atoms, alkyl groups with 1 to 4 carbon atoms, fluoroalkyl groups with 1 to 4 carbon atoms, alkoxy groups with 1 to 4 carbon atoms, cyano groups or nitro groups. The methylene group contained in the alicyclic hydrocarbon group may be substituted by -O-, -S- or -NH-.

E ¹ , E ² , B ¹ and B ² independently represent -CR ⁵ R ⁶ -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, - O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ⁵ -, -NR ⁵ -CO-, - O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or single bond. R ⁵ and R ⁶ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.

A ¹ and A ² each independently represent a divalent alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group. The hydrogen atoms contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group may be substituted by halogen atoms, alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, cyano groups or nitro groups. The hydrogen atoms contained in the alkyl group having 1 to 4 carbon atoms and the alkoxy group having 1 to 4 carbon atoms may be substituted with fluorine atoms.

k and l independently represent integers from 0 to 3.

F ¹ and F ² each independently represent an alkylene group having 1 to 12 carbon atoms. The hydrogen atom contained in the alkylene group may be substituted by an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a halogen atom, and the methylene group contained in the alkylene group may be substituted by -O- or -CO- replace.

P ¹ and P ² each independently represent a hydrogen atom or a polymerizable group (but at least one of P ¹ and P ² represents a polymerizable group). ]

Compound (1) preferably satisfies the necessary conditions shown in formula (2) and formula (3).

(N _π -4)/3<k+l+4 (2)

12≦ _Nπ ≦22 (3)

[In Formula (2) and Formula (3), N _π , k and l have the same meanings as described above. ]

Examples of aromatic hydrocarbon rings include benzene ring, naphthalene ring, anthracene ring, phenanthroline ring, and the like. Examples of the aromatic heterocyclic ring include a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, a benzothiazole ring, and the like. Among these, benzene ring, thiazole ring and benzothiazole ring are preferred.

Ar is a divalent group having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The total number of π electrons N _π of the aromatic rings contained in the divalent group is preferably 12 or more. It is 12 or more and 22 or less, more preferably, it is 13 or more and 22 or less.

Ar is preferably a divalent group having at least two aromatic rings selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles.

In formula (1), Ar is preferably any divalent group represented by formula (Ar-1) to formula (Ar-13).

[In Formula (Ar-1) to Formula (Ar-13), Z ¹ represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkyl sulfinyl group having 1 to 6 carbon atoms, Alkyl sulfonyl group with 1 to 6 carbon atoms, carboxyl group, fluoroalkyl group with 1 to 6 carbon atoms, alkoxy group with 1 to 6 carbon atoms, alkylthio group with 1 to 6 carbon atoms, alkylthio group with 1 to 6 carbon atoms N-alkylamino group, N,N-dialkylamino group having 2 to 12 carbon atoms, N-alkylamine sulfonyl group having 1 to 6 carbon atoms or N,N-dihydrocarbon group having 2 to 12 carbon atoms Alkylamine sulfonyl.

Q ¹ and Q ³ independently represent -CR ⁷ R ⁸ -, -S-, -NR ⁷ -, -CO- or -O-.

R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Y ¹ , Y ² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group that may be substituted.

W ¹ and W ² independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom.

m represents an integer from 0 to 6.

n represents an integer from 0 to 2. ]

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. Among them, fluorine atom, chlorine atom and bromine atom are preferred.

Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, second butyl, third butyl, pentyl, hexyl, and the like. Among them, an alkyl group having 1 to 4 carbon atoms is preferred, an alkyl group having 1 to 2 carbon atoms is more preferred, and a methyl group is particularly preferred.

Examples of the alkyl sulfenyl group having 1 to 6 carbon atoms include methyl sulfenyl group, ethyl sulfenyl group, propyl sulfenyl group, isopropyl sulfenyl group, and butyl sulfenyl group. , isobutyl sulfenyl group, second butyl sulfenyl group, third butyl sulfenyl group, pentyl sulfenyl group, hexyl sulfenyl group, etc. Among them, an alkylsulfinyl group having 1 to 4 carbon atoms is preferred, an alkylsulfinyl group having 1 to 2 carbon atoms is more preferred, and methylsulfinyl group is particularly preferred.

Examples of the alkylsulfonyl group having 1 to 6 carbon atoms include methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, isopropylsulfonyl group, butylsulfonyl group, and isobutylsulfonyl group base, second butylsulfonyl group, third butylsulfonyl group, amylsulfonyl group, hexylsulfonyl group, etc. Among them, an alkylsulfonyl group having 1 to 4 carbon atoms is preferred, an alkylsulfonyl group having 1 to 2 carbon atoms is more preferred, and a methylsulfonyl group is particularly preferred.

Examples of the fluoroalkyl group having 1 to 6 carbon atoms include fluoromethyl, trifluoromethyl, fluoroethyl, pentafluoroethyl, heptafluoropropyl, nonafluorobutyl, and the like. Among them, a fluoroalkyl group having 1 to 4 carbon atoms is preferred, a fluoroalkyl group having 1 to 2 carbon atoms is more preferred, and trifluoromethyl is particularly preferred.

Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, 2nd butoxy, 3rd butoxy, Pentyloxy, hexyloxy, etc. Among them, an alkoxy group having 1 to 4 carbon atoms is preferred, an alkoxy group having 1 to 2 carbon atoms is more preferred, and a methoxy group is particularly preferred.

Examples of the alkylthio group having 1 to 6 carbon atoms include methylthio group, ethylthio group, propylthio group, isopropylthio group, butylthio group, isobutylthio group, and second butylthio group. base, third butylthio group, pentylthio group, hexylthio group, etc. Among them, an alkylthio group having 1 to 4 carbon atoms is preferred, an alkylthio group having 1 to 2 carbon atoms is more preferred, and a methylthio group is particularly preferred.

Examples of the N-alkylamino group having 1 to 6 carbon atoms include N-methylamino group, N-ethylamine group, N-propylamine group, N-isopropylamine group, N-butylamine group and N-isobutylamine group. , N-second butylamine group, N-third butylamine group, N-pentylamine group, N-hexylamine group, etc. Among them, an N-alkylamino group having 1 to 4 carbon atoms is preferred, an N-alkylamino group having 1 to 2 carbon atoms is more preferred, and an N-methylamino group is particularly preferred.

Examples of the N,N-dialkylamino group having 2 to 12 carbon atoms include N,N-dimethylamino group, N-methyl-N-ethylamine group, N,N-diethylamine group, and N,N -Dipropylamine, N,N-diisopropylamine, N,N-dibutylamine, N,N-diisobutylamine, N,N-dipentylamine, N,N-dihexylamine wait. Among them, an N,N-dialkylamino group having 2 to 8 carbon atoms is preferred, an N,N-dialkylamino group having 2 to 4 carbon atoms is more preferred, and an N,N-dimethylamino group is particularly preferred. .

Examples of the N-alkylaminesulfonyl group having 1 to 6 carbon atoms include N-methylaminesulfonyl group, N-ethylaminesulfonyl group, N-propylaminesulfonyl group, N-isopropylaminesulfonyl group, and N- Butylamine sulfonyl, N-isobutylamine sulfonyl, N-second butylamine sulfonyl, N-tert-butylamine sulfonyl, N-pentylamine sulfonyl, N-hexylamine sulfonyl wait. Among them, N-alkylamine sulfonyl group having 1 to 4 carbon atoms is preferred, N-alkylamine sulfonyl group having 1 to 2 carbon atoms is more preferred, and N-methylaminesulfonyl group is particularly preferred.

Examples of the N,N-dialkylaminesulfonyl group having 2 to 12 carbon atoms include N,N-dimethylaminesulfonyl group, N-methyl-N-ethylaminesulfonyl group, and N,N-diethyl group. Aminesulfonyl, N,N-dipropylaminesulfonyl, N,N-diisopropylaminesulfonyl, N,N-dibutylaminesulfonyl, N,N-diisobutylaminesulfonyl, N , N-dipentylamine sulfonyl, N,N-dihexylamine sulfonyl, etc. Among them, N,N-dialkylaminesulfonyl group having 2 to 8 carbon atoms is preferred, N,N-dialkylaminesulfonyl group having 2 to 4 carbon atoms is more preferred, and N,N- dialkylaminesulfonyl group having 2 to 4 carbon atoms is particularly preferred. Dimethylamine sulfonyl.

Z ¹ is preferably a halogen atom, methyl, cyano, nitro, carboxyl, methylsulfonyl, trifluoromethyl, methoxy, methylthio, N-methylamino, N,N-di Methylamine group, N-methylaminesulfonyl group or N,N-dimethylaminesulfonyl group.

Examples of the alkyl group having 1 to 4 carbon atoms in R ⁷ and R ⁸ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and the like. Among them, an alkyl group having 1 to 2 carbon atoms is preferred, and a methyl group is more preferred.

Q ¹ is preferably -S-, -CO-, -NH-, -N(CH ₃ )-, and Q ³ is preferably -S-, -CO-.

Examples of the aromatic hydrocarbon group in Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthracenyl, phenanthrenyl, and biphenyl groups. Among them, phenyl and naphthyl are preferred, and phenyl is more preferred. Examples of the aromatic heterocyclic group include furyl, pyrrolyl, thienyl, pyridyl, thiazolyl, benzothiazolyl and other aromatic groups containing at least one heteroatom such as nitrogen atom, oxygen atom, sulfur atom and having 4 to 20 carbon atoms. The heterocyclic group is preferably furyl, pyrrolyl, thienyl, pyridyl or thiazolyl.

The aromatic hydrocarbon group and aromatic heterocyclic group may have at least one substituent. Examples of the substituent include a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, and an alkyl sulfenyl group having 1 to 6 carbon atoms. Cyl group, alkylsulfonyl group with 1 to 6 carbon atoms, carboxyl group, fluoroalkyl group with 1 to 6 carbon atoms, alkoxy group with 1 to 6 carbon atoms, alkylthio group with 1 to 6 carbon atoms, carbon number N-alkylamino group with 1 to 6 carbon atoms, N,N-dialkylamino group with 2 to 12 carbon atoms, N-alkylaminosulfonyl group with 1 to 6 carbon atoms, N with 2 to 12 carbon atoms, N-Dialkylaminosulfonyl, etc. Among them, preferred are a halogen atom, an alkyl group having 1 to 2 carbon atoms, a cyano group, a nitro group, an alkylsulfonyl group having 1 to 2 carbon atoms, a fluoroalkyl group having 1 to 2 carbon atoms, and a fluoroalkyl group having 1 to 2 carbon atoms. Alkoxy group, alkylthio group with 1 to 2 carbon atoms, N-alkylamino group with 1 to 2 carbon atoms, N,N-dialkylamino group with 2 to 4 carbon atoms, N,N-dialkylamino group with 1 to 2 carbon atoms Alkylamine sulfonyl.

Halogen atom, alkyl group with 1 to 6 carbon atoms, cyano group, nitro group, alkylsulfenyl group with 1 to 6 carbon atoms, alkylsulfenyl group with 1 to 6 carbon atoms, carboxyl group, 1 to 6 carbon atoms Fluoroalkyl group, alkoxy group with 1 to 6 carbon atoms, alkylthio group with 1 to 6 carbon atoms, N-alkylamino group with 1 to 6 carbon atoms, N,N-dicarbonyl group with 2 to 12 carbon atoms Examples of the alkylamino group, the N-alkylamine sulfonyl group having 1 to 6 carbon atoms, and the N,N-dialkylamine sulfonyl group having 2 to 12 carbon atoms are the same as those described above.

Y ¹ , Y ² and Y ³ are each independently preferably any group represented by formula (Y-1) to formula (Y-6).

[In formulas (Y-1) to formula (Y-6), Z ² represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkyl sulfenyl group having 1 to 6 carbon atoms, Alkylsulfonyl group with 1 to 6 carbon atoms, carboxyl group, fluoroalkyl group with 1 to 6 carbon atoms, alkoxy group with 1 to 6 carbon atoms, sulfanyl group with 1 to 6 carbon atoms, sulfanyl group with 1 to 6 carbon atoms N-alkylamino group, N,N-dialkylamino group with 2 to 12 carbon atoms, N-alkylaminosulfonyl group with 1 to 6 carbon atoms or N,N-dioxane with 2 to 12 carbon atoms Ammonium sulfonyl group.

a ¹ represents an integer from 0 to 5, a ² represents an integer from 0 to 4, b ¹ represents an integer from 0 to 3, b ² represents an integer from 0 to 2, and R represents a hydrogen atom or a methyl group. ]

Z ² is preferably a halogen atom, methyl, cyano group, nitro group, styrene group, carboxyl group, trifluoromethyl group, methoxy group, thiomethyl group, N,N-dimethylamino group or N-methylamino group.

Furthermore, from the viewpoint of the production steps or cost of the compound (1), it is particularly preferred that Y ¹ , Y ² and Y ³ each independently be a group represented by formula (Y-1) or formula (Y-3).

W ¹ and W ² are each independently preferably a hydrogen atom, a cyano group or a methyl group, and particularly preferably a hydrogen atom.

m is preferably 0 or 1. n is preferably 0.

In formula (1), Ar is preferably a group represented by formula (Ar-6), and more preferably formula (Ar-6a), formula (Ar-6b), formula (Ar-6c), formula (Ar- A divalent group represented by 10a) or (Ar-10b).

[In formula (Ar-6a) to formula (Ar-6c), formula (Ar-10a) and formula (Ar-10b), Z ¹ , n, Q ¹ , Z ² , a ¹ and b ¹ represent the same as above meaning. ]

Examples of Ar are shown in formula (ar-1) to formula (ar-189).

Specific examples of the group represented by formula (Ar-1) to formula (Ar-4) include groups represented by formula (ar-1) to formula (ar-29).

Specific examples of the group represented by formula (Ar-5) include groups represented by formula (ar-30) to formula (ar-39).

Specific examples of the group represented by formula (Ar-6) or formula (Ar-7) include groups represented by formula (ar-40) to formula (ar-119).

Specific examples of the group represented by formula (Ar-8) or formula (Ar-9) include groups represented by formula (ar-120) to formula (ar-129).

Specific examples of the group represented by formula (Ar-10) include groups represented by formula (ar-130) to formula (ar-149).

Specific examples of the group represented by formula (Ar-11) include groups represented by formula (ar-150) to formula (ar-159).

Specific examples of the group represented by formula (Ar-12) include groups represented by formula (ar-160) to formula (ar-179).

Specific examples of the group represented by formula (Ar-13) include groups represented by formula (ar-180) to formula (ar-189).

D ¹ and D ² are preferably *-O-CO-, *-OC(=S)-, *-O-CR ¹ R ² -, *-NR ¹ -CR ² R ³ - or *-NR ¹ - CO- (* represents the bonding site of Ar). D ¹ and D ² are more preferably *-O-CO-, *-OC(=S)- or *-NR1-CO- (* represents the bonding site of Ar). R ¹ , R ² , R ³ and R ⁴ are each independently preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, methyl or ethyl group.

Examples of G ¹ and G ² include alicyclic hydrocarbon groups represented by formulas (g-1) to formula (g-10) which may contain heteroatoms, and are preferably alicyclic hydrocarbon groups with a 5-membered ring or a 6-membered ring.

The groups represented by the aforementioned formulas (g-1) to (g-10) can be alkyl groups with 1 to 4 carbon atoms such as methyl, ethyl, isopropyl, tert-butyl, etc.; methoxy, ethoxy Alkoxy groups with 1 to 4 carbon atoms such as trifluoromethyl; fluoroalkoxy groups with 1 to 4 carbon atoms such as trifluoromethoxy; cyano group; nitro group; fluorine Atoms, chlorine atoms, bromine atoms and other halogen atoms are substituted.

G ¹ and G ² are preferably an alicyclic hydrocarbon group composed of a 6-membered ring represented by formula (g-1), more preferably a 1,4-cyclohexyl group, and particularly preferably a trans-1,4-cyclohexyl group. Jiji.

Examples of the divalent alicyclic hydrocarbon group or aromatic hydrocarbon group in A ¹ and A ² include alicyclic formulas composed of a 5-membered ring or a 6-membered ring represented by the aforementioned formula (g-1) to formula (g-10). A hydrocarbon group or a divalent aromatic hydrocarbon group having about 6 to 20 carbon atoms represented by formula (a-1) to formula (a-8).

In addition, a part of the hydrogen atoms of the aforementioned groups of A ¹ and A ² may be alkyl groups having about 1 to 4 carbon atoms such as methyl, ethyl, isopropyl or tert-butyl; methoxy or ethoxy groups, etc. Alkoxy group with about 1 to 4 carbon atoms; trifluoromethyl group; trifluoromethyloxy group; cyano group; nitro group; halogen atom substitution such as fluorine atom, chlorine atom or bromine atom.

In particular, it is preferable if both A ¹ and A ² are the same group because compound (1) can be easily produced. Moreover, ^A1 and ^A2 are preferably a monocyclic 1,4-phenylene group or a 1,4-cyclohexylene group, and particularly preferably a 1,4-phenylene group because the compound (1) can be easily produced.

It is preferable if B ¹ and B ² are divalent groups of the same type because compound (1) can be easily produced. Furthermore, from the viewpoint of ease of production of compound (1), among B ¹ and B ² , B ¹ and B ² that are only bonded to A ¹ and A ² are preferably -CH ₂ -CH ₂ -, -CO respectively. -O-, -O-CO-, -CO-NH-, -NH-CO-, -O-CH ₂ -, -CH ₂ -O- or single bond, especially in terms of high liquid crystallinity, is preferred is -CO-O- or -O-CO-. Among B ¹ and B ² , B ¹ and B ² bonded to E ¹ or E ² are preferably -O-, -CO-O-, -O-CO-, -O-CO-O-, respectively. , -CO-NH-, -NH-CO- or single bond.

From the viewpoint of liquid crystallinity, it is preferable that k and l are each independently an integer representing 0 to 3, and more preferably k and l are 0 to 2. The total of k and l is preferably 5 or less, more preferably 4 or less.

P ¹ and P ² each independently represent a hydrogen atom or a polymerizable group (but at least one of P ¹ and P ² represents a polymerizable group). If both P ¹ and P ² are polymerizable groups, the obtained retardation film tends to have excellent film hardness, so it is preferable.

The polymerizable group refers to a substituent that can polymerize the compound (1) of the present invention, and specific examples thereof include vinyl, p-stilbenyl, acryloyl, methacryloyl, acryloyloxy, and methacryl. Cyloxy group, carboxyl group, methylcarbonyl group, hydroxyl group, amide group, alkylamine group with 1 to 4 carbon atoms, amine group, epoxy group, oxetanyl group, aldehyde group, isocyanate group or isothiocyanate Ester group etc. In addition, the polymerizable group may contain groups represented by B ¹ and B ² in order to bond the aforementioned exemplified groups to E ¹ and E ² . For example, a radically polymerizable or cationically polymerizable group suitable for photopolymerization is preferred. In particular, in terms of easy handling and easy production, an acrylyl group or a methacryloyl group is preferred, and an acrylyl group is more preferred. If both P ¹ and P ² are polymerizable groups, the resulting retardation film tends to have excellent film hardness, so it is more preferable.

-D ¹ -G ¹ -E ¹ -(A ¹ -B ¹ ) _k -F ¹ -P ¹ , -D ² -G ² -E ² -(A ² -B ² ) _l -F ² -P ² Examples include groups represented by formula (R-1) to formula (R-134). *(star) indicates the bonding position with Ar. In addition, n in Formula (R-1) to Formula (R-134) represents an integer from 2 to 12.

Moreover, compounds (1) include compounds (i) to compounds (xxxiv). R1 in the table represents -D ¹ -G ¹ -E ¹ -(A ¹ -B ¹ ) _k -F ¹ -P ¹ , R2 represents -D ² -G ² -E ² -(A ² -B ² ) _l -F ² -P ² .

[Table 1]

Moreover, in compound (xxx) and compound (xxxi), any one of R1 and R2 is any one of (R-57) to (R-120).

In the aforementioned Table 1, compound (xvii) refers to a compound in which the group represented by Ar is a group represented by formula (ar-78), a compound in which the group represented by Ar is a group represented by formula (ar-79), or The group represented by Ar is any mixture of a compound of a group represented by formula (ar-78) and a compound of a group represented by formula (ar-79).

In the aforementioned Table 2, compound (xxx) refers to a compound in which the group represented by Ar is a group represented by formula (ar-120), a compound in which the group represented by Ar is a group represented by formula (ar-121), or Any mixture of compounds in which the group represented by Ar is the group represented by formula (ar-120) and compounds represented by formula (ar-121). Compound (xxxi) means that the group represented by Ar is Compounds of the group represented by formula (ar-122), compounds in which the group represented by Ar is the group represented by formula (ar-123), or compounds in which the group represented by Ar is the group represented by formula (ar-122) Any mixture of a compound and a compound of a base represented by formula (ar-123).

In addition, the representative structural formulas of the compounds shown in Table 1 are exemplified below. When forming a retardation film, a plurality of different compounds (1) can be used.

Further examples of compound (1) include the following. However, n1 and n2 in the formula independently represent integers from 2 to 12.

Compound (1) can be appropriately combined according to its structure in known organic synthesis reactions (such as condensation reaction, esterification reaction, William Williamson reaction, Ullman reaction, Wittig reaction, Schiff base formation reaction, benzylation reaction, Shazuzu reaction, Suzuki-Miyaura reaction, Negishi reaction, Kumada reaction , Hiyama reaction, Buchwald-Hartwig reaction, Friedel-Claude reaction, Heck reaction, aldol reaction, etc.), and are manufactured by this.

For example, when D ¹ and D ² are compound (1) of *-O-CO-, the compound represented by formula (1-1) and the compound represented by formula (1-2) are reacted to obtain formula (1- The compound represented by 3) can be produced by reacting the obtained compound represented by formula (1-3) with the compound represented by formula (1-4).

HO-Ar-OH (1-1)

(In the formula, Ar means the same meaning as mentioned above.)

(In the formula, G ¹ , E ¹ , A ¹ , B ¹ , F ¹ , P ¹ and k have the same meaning as above.)

(In the formula, Ar, G ¹ , E ¹ , A ¹ , B ¹ , F ¹ , P ¹ and k have the same meanings as above.)

(In the formula, G ² , E ² , A ² , B ² , F ² , P ² and l represent the same meaning as above.)

The reaction of the compound represented by formula (1-1) and the compound represented by formula (1-2) and the reaction of the compound represented by formula (1-3) and the compound represented by formula (1-4) are preferably in the esterification agent implemented in existence.

From the viewpoint of reactivity, cost, and usable solvents, the esterification agent (condensation agent) is preferably dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbon Diimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, bis(2,6-diisopropylphenyl)carbodiimide, bis(tris) Methylsilyl)carbodiimide, bisisopropylcarbodiimide, 2,2'-carbonylbis-1H-imidazole.

In addition to the compound represented by formula (1), the composition containing polymerizable liquid crystal may contain other liquid crystal compounds (but different from compound (1)).

It is also preferable that other liquid crystal compounds have polymerizable groups. Specific examples of other liquid crystal compounds include 3.2 Achiral Rod-shaped Liquid Crystal Molecules in Chapter 3 Molecular Structure and Liquid Crystallinity of the Liquid Crystal Guide (Compiled by the Liquid Crystal Guide Compilation Committee, Maruzen Co., Ltd., published on October 30, 2012). 3.3 Chiral rod-shaped liquid crystal molecules are compounds having a polymerizable group among the described compounds.

Different plural compounds may be used together with other liquid crystal compounds.

Examples of other liquid crystal compounds include the compound represented by formula (4) (hereinafter referred to as "compound (4)").

P ¹¹ -E ¹¹ -(B ¹¹ -A ¹¹ ) _t -B ¹² -G (4)

[In the formula (4), A ¹¹ represents an aromatic hydrocarbon group, an alicyclic hydrocarbon group or a heterocyclic group. The hydrogen atom contained in the aromatic hydrocarbon group, an alicyclic hydrocarbon group and the heterocyclic group can be converted into a halogen atom, a carbon number of 1 to 6 alkyl groups, alkoxy groups with 1 to 6 carbon atoms, alkylamino groups with 1 to 6 carbon atoms, nitro groups, nitrile groups or mercapto groups.

B ¹¹ and B ¹² independently represent -CR ¹⁴ R ¹⁵ -, -C≡C-, -CH=CH-, -CH ₂ -CH ₂ -, -O-, -S-, -CO-, -CO- O-, -O-CO-, -O-CO-O-, -C(=S)-, -C(=S)-O-, -OC(=S)-, -CH=N-, - N=CH-, -N=N-, -CO-NR ¹⁴ -, -NR ¹⁴ -CO-, -OCH ₂ -, -OCF ₂ -, -NR ¹⁴ -, -CH ₂ O-, -CF ₂ O -, -CH=CH-CO-O-, -O-CO-CH=CH- or single bond. R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms. R ¹⁴ and R ¹⁵ may be connected to form an alkylene group having 4 to 7 carbon atoms.

E ¹¹ represents an alkylene group having 1 to 12 carbon atoms. The hydrogen atom contained in the alkylene group may be substituted by an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

P ¹¹ represents a polymerizable group.

G represents a hydrogen atom, a halogen atom, an alkyl group with 1 to 13 carbon atoms, an alkoxy group with 1 to 13 carbon atoms, a fluoroalkyl group with 1 to 13 carbon atoms, an alkylamino group with 1 to 13 carbon atoms, or a nitrile group. , nitro group, or a polymeric group bonded through an alkylene group having 1 to 12 carbon atoms. The hydrogen atom contained in the alkylene group can be passed through an alkyl group having 1 to 6 carbon atoms or an alkyl group having 1 to 6 carbon atoms. Oxygen or halogen atom substitution.

t represents an integer from 1 to 5. ]

In particular, the polymerizable group in P ¹¹ and G only needs to be a group polymerizable with the compound (1), and examples thereof include vinyl, vinyloxy, p-stilbene, acrylyl, acryloxy, and methyl groups. Acrylyl group, methacryloxy group, carboxyl group, acetyl group, hydroxyl group, aminoformyl group, amine group, alkylamino group with 1 to 4 carbon atoms, epoxy group, oxetanyl group, methyl group Carboxylic acid group, -N=C=O or N=C=S, etc. Among them, a radical polymerizable group or a cationic polymerizable group is preferable from the viewpoint of being suitable for photopolymerization, and an acryloxy group or a methacrylate group is preferable since it is easy to handle and can easily produce a liquid crystal compound. Oxygen or vinyloxy.

Furthermore, the carbon numbers of the aromatic hydrocarbon group, alicyclic hydrocarbon group and heterocyclic group of A ¹¹ are, for example, 3 to 18, preferably 5 to 12, and particularly preferably 5 or 6.

Examples of compound (4) include compounds represented by formula (4-1) and formula (4-2).

P ¹¹ -E ¹¹ -(B ¹¹ -A ¹¹ ) _t1 -B ¹² -E ¹² -P ¹² (4-1)

P ¹¹ -E ¹¹ -(B ¹¹ -A ¹¹ ) _t2 -B ¹² -F ¹¹ (4-2)

[In Formula (4-1) and Formula (4-2), P ¹¹ , E ¹¹ , B ¹¹ , A ¹¹ , and B ¹² have the same meanings as mentioned above.

F ¹¹ represents a hydrogen atom, a halogen atom, an alkyl group with 1 to 13 carbon atoms, an alkoxy group with 1 to 13 carbon atoms, a fluoroalkyl group with 1 to 13 carbon atoms, an alkylamino group with 1 to 13 carbon atoms, or cyanide Base, nitro.

E ¹² has the same meaning as E ¹¹ .

P ¹² has the same meaning as P ¹¹ .

t ¹ and t ² have the same meaning as t. ]

Moreover, the compounds represented by formulas (4-1) and (4-2) include compounds represented by formula (I), formula (II), formula (III), formula (IV) or formula (V).

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A 13 -B ¹⁴ -A ¹⁴ -B ¹⁵ -A ¹⁵ -B ^{16 -E 12} -P ¹² (I)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A ¹³ -B ¹⁴ -A ¹⁴ -B ¹⁵ -E ¹² -P ¹² (II)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A ¹³ -B ¹⁴ -E ¹² -P ¹² (III)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -A ¹³ -B ¹⁴ -F ¹¹ (IV)

P ¹¹ -E ¹¹ -B ¹¹ -A ¹¹ -B ¹² -A ¹² -B ¹³ -F ¹¹ (V)

[In formula (I) to formula (V), A ¹² to A ¹⁵ have the same meaning as A ¹¹ , and B ¹³ to B ¹⁶ have the same meaning as B ¹¹ ].

Moreover, among the compounds represented by formula (4-1), formula (4-2), formula (I), formula (II), formula (III), formula (IV) and formula (V), the preferred ones are suitable for selection A combination of P ¹¹ and E ¹¹ , and a combination of P ¹² and E ¹² are suitably selected, and the two are bonded via an ether bond or an ester bond.

Specific examples of the compound (4) include the following formulas (I-1) to formula (I-5), formula (II-1) to formula (II-6), formula (III-1) to formula (III- 19), compounds represented by formula (IV-1) to formula (IV-14), formula (V-1) to formula (V-5), etc. But k in the formula represents an integer from 1 to 11. These liquid crystal compounds are preferred because they are easy to synthesize and are commercially available.

When using other liquid crystal compounds, the usage amount is, for example, 90 parts by weight or less based on 100 parts by weight of the total of other liquid crystal compounds and compound (1).

The composition containing polymerizable liquid crystal (hereinafter referred to as "liquid crystal composition") preferably further contains a polymerization initiator. The polymerization initiator is preferably a photopolymerization initiator. Examples of the photopolymerization initiator include benzoins, benzophenones, benzyl ketals, α-hydroxyketones, α-aminoketones, iodonium salts or sulfonium salts, and more specific examples thereof include IRGACURE 907, IRGACURE 184, IRGACURE 651, IRGACURE 819, IRGACURE 250, IRGACURE 369 (the above are all made by Ciba Specialty Chemicals), SEIKUOL BZ, SEIKUOL Z, SEIKUOL BEE (the above are all made by Seiko Chemical Co., Ltd.), KAYACURE BP100 (manufactured by Nippon Kayaku Co., Ltd.), KAYACURE UVI-6992 (manufactured by DOW Corporation), ADEKAOPTOMER SP-152 or ADEKAOPTOMER SP-170 (all of the above are manufactured by ADEKA Co., Ltd.), etc.

The usage amount of the polymerization initiator is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight relative to 100 parts by weight of the polymerizable liquid crystal. If the usage amount of the polymerization initiator is within the aforementioned range, the compound (1) can be polymerized without disturbing the alignment.

The wavelength dispersion characteristics of the retardation film can be arbitrarily determined based on the content of the structural unit derived from the compound (1). If the content of the structural unit derived from the compound (1) is increased in the structural unit in the retardation film, a flatter wavelength dispersion characteristic can be displayed, and the reverse wavelength dispersion satisfying the formulas (α) and (β) can be further demonstrated. characteristic.

The wavelength dispersion characteristics of the retardation film can be confirmed through appropriate preliminary experiments. The following shows preliminary experiments using the preferred polymerizable liquid crystal compound (1). About 2 to 5 types of liquid crystal compositions with different contents of structural units derived from compound (1) are prepared. Each liquid crystal composition is as described below. Retardation films of the same film thickness are produced and the phase difference value of the obtained retardation films is determined. , from the results, the correlation between the content of the structural unit derived from compound (1) and the retardation value of the retardation film is determined, and the obtained retardation value used to impart the retardation film to the aforementioned film thickness is determined. The required content of structural units derived from compound (1) is sufficient.

The thickness of the retardation film can be set to obtain the most appropriate function of the λ/4 plate. The thickness of the retardation film is preferably 1.5 to 10 μm, more preferably 1.5 to 8 μm, and particularly preferably 1.5 to 5 μm.

(Method for manufacturing a retardation film that functions as a λ/4 plate)

The manufacturing method of the retardation film is explained below. First, additives such as organic solvents, other liquid crystal compounds, polymerization initiators, polymerization inhibitors, photosensitizers or leveling agents are added to compound (1) as necessary to prepare a liquid crystal composition. In particular, since film formation is easy, the liquid crystal composition is preferably in a liquid state. Furthermore, the liquid crystal composition preferably contains an organic solvent. Since it has the function of hardening the obtained retardation film, the liquid crystal composition preferably contains a polymerization initiator.

The usage amount of the polymerization initiator is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight relative to 100 parts by weight of the polymerizable liquid crystal. If it is within the aforementioned range, the polymerizable liquid crystal can be polymerized without disturbing the alignment of the polymerizable liquid crystal.

[Polymerization inhibitor]

The liquid crystal composition may contain a polymerization inhibitor. Examples of polymerization inhibitors include hydroquinones or hydroquinones having a substituent such as an alkyl ether, catechols such as butyl catechol having a substituent such as an alkyl ether, pyrogallols, 2, Free radical foot supplements such as 2,6,6-tetramethyl-1-piperidyloxy radical, thiophenols, β-naphthylamines or β-naphthols, etc.

By using a polymerization inhibitor, the polymerization of the polymerizable liquid crystal can be controlled, and the stability of the resulting retardation film can be improved. The usage amount of the polymerization inhibitor is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight relative to 100 parts by weight of the polymerizable liquid crystal. If it is within the aforementioned range, the polymerizable liquid crystal can be polymerized without disturbing the alignment of the liquid crystal compound. In addition, when other liquid crystal compounds are used in addition to the polymerizable liquid crystal compound (1), the preferred usage amount of the polymerization inhibitor is approximately the same as described above.

[Photosensitizer]

The liquid crystal composition may contain a photosensitizer. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone, anthracenes having a substituent such as anthracene or alkyl ether, phenothiazine or rubrene.

By using a photosensitizer, polymerization of polymerizable liquid crystal can be made highly sensitive. The usage amount of the photosensitizer is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight relative to 100 parts by weight of the polymerizable liquid crystal. If it is within the aforementioned range, polymerization can be performed without disrupting the alignment of the polymerizable liquid crystal. In addition, when other liquid crystal compounds are used in addition to the polymerizable liquid crystal compound (1), the preferred usage amount of the photosensitizer is approximately the same as described above.

[Leveling agent]

The liquid crystal composition may contain a leveling agent. Examples of the leveling agent include additives for radiation hardening paints (BYK JAPAN: BYK-352, BYK-353, BYK-361N), paint additives (TORAY.DOW CORNING Co., Ltd.: SH28PA, DC11PA, ST80PA), paint additives (Xinyuehua Gaku Kogyo Co., Ltd.: KP321, KP323, X22-161A, KF6001) or fluorine additives (Dainippon Ink Chemical Co., Ltd.: F-445, F-470, F-479), etc.

The retardation film can be smoothed by using a leveling agent. Furthermore, the fluidity of the liquid crystal composition can be controlled during the manufacturing process of the optical film, or the cross-linking density of the obtained retardation film can be adjusted. The usage amount of the leveling agent is 0.1 to 30 parts by weight relative to 100 parts by weight of the polymerizable liquid crystal, preferably 0.5 to 10 parts by weight. If it is within the aforementioned range, the polymerizable liquid crystal can be polymerized without disturbing the alignment of the polymerizable liquid crystal.

[Organic solvent]

As mentioned above, the liquid crystal composition preferably contains an organic solvent. The organic solvent used for preparing the liquid crystal composition is preferably an organic solvent that can dissolve polymerizable liquid crystal. In addition, any solvent is sufficient as long as it is inert to the polymerization reaction. Specific examples include alcohols such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve; ethyl acetate, Ester solvents such as butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone or propylene glycol methyl ether acetate; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl Ketone solvents such as pentanone or methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane or heptane; aromatic hydrocarbon solvents such as toluene, xylene or chlorobenzene, acetonitrile, propylene glycol monomethyl ether, tetrahydrofuran, Dimethoxyethane, ethyl lactate, chloroform, phenol, etc. These organic solvents can be used individually or in combination. In particular, the composition of this embodiment has excellent compatibility and is soluble in alcohol, ester solvents, ketone solvents, non-chlorinated aliphatic hydrocarbon solvents, non-chlorinated aromatic hydrocarbon solvents, etc., so it can be used even without using halogenated hydrocarbons such as chloroform. Can also be dissolved and coated.

In order to facilitate coating, the viscosity of the liquid crystal composition is preferably adjusted to, for example, 10 Pa. s or less, preferably 0.1 to 7Pa. around s.

The solid content concentration in the liquid crystal composition is, for example, 5 to 50% by weight. If the solid content concentration is 5% or more, the retardation film tends not to be too thin, so it is preferable. In addition, if it is 50% or less, the film thickness of the retardation film tends to be uneven, so it is preferable.

Next, the liquid crystal composition can be coated on the supporting base material, dried and polymerized, and the desired retardation film can be obtained on the supporting base material. The production of the retardation film will be described in detail below.

[Unpolymerized film preparation step]

The liquid crystal composition is applied on the supporting base material and dried to obtain an unpolymerized film. When the unpolymerized film exhibits a liquid crystal phase such as a nematic phase, the resulting retardation film has birefringence due to single-region alignment. The unpolymerized film can be aligned at a low temperature of about 0 to 120°C, preferably 25 to 80°C. Therefore, the alignment film can use a support substrate that does not necessarily meet the heat resistance as exemplified above. In addition, even if it is further cooled to about 30 to 10°C after alignment, it will not crystallize, so it is easy to handle. Furthermore, the film thickness can be adjusted so as to impart a desired phase difference by appropriately adjusting the coating amount or concentration of the composition.

Examples of coating methods for the liquid crystal composition on the supporting substrate include extrusion coating, direct gravure coating, inversion gravure coating, CAP coating, or die coating. Furthermore, a method of coating using a coater such as a dip coater, a rod coater, or a spin coater is included.

Examples of the aforementioned support substrate include glass, plastic sheets, plastic films, or light-transmitting films. Examples of the translucent film include polyolefin films such as polyethylene, polypropylene, and norbornene-based polymers, polyvinyl alcohol films, polyethylene terephthalate films, polymethacrylate films, and polyethylene films. Acrylic ester film, cellulose ester film, polyethylene naphthalate film, polycarbonate film, polystyrene film, polyether styrene film, polyetherketone film, polyphenylene sulfide film or polyphenylene ether film, etc.

For example, in steps that require film strength such as the laminating step, transportation step, and storage step of the retardation film, the support base material can be used so that it can be easily handled without cracking.

Furthermore, it is preferable to form an alignment film on a supporting base material and apply the liquid crystal composition on the alignment film. The alignment film preferably has solvent resistance that does not dissolve in the liquid crystal composition when the liquid crystal composition is coated, heat resistance during solvent removal or heat treatment, and does not cause peeling due to friction during rubbing (rubbing). . The alignment film can be formed from a composition containing a suitable polymer (alignment film forming composition).

Examples of the aforementioned polymer include polyamide or gelatin having an amide bond in the molecule, polyamide imine having an amide imine bond in the molecule, and polyamide acid, polyvinyl alcohol, and alkyl hydrolyzates thereof. Modified polymers such as polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylate esters. These polymers may be used alone, two or more types may be mixed, or a copolymer may be used. These polymers can be easily obtained by polycondensation such as dehydration or deamination, chain polymerization such as radical polymerization, anionic polymerization, or cationic polymerization, coordination polymerization, ring-opening polymerization, or the like.

These polymers are preferably soluble in solvents and can be coated. The solvent can be selected to suit the dissolution of the polymer used. Specific examples of the solvent include alcohols such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve; ethyl acetate, butyl acetate, and ethylene glycol methyl ether. Ester solvents such as acid ester, γ-butyrolactone or propylene glycol methyl ether acetate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl pentanone or methyl isobutyl ketone Solvents; aliphatic hydrocarbon solvents such as pentane, hexane or heptane; aromatic hydrocarbon solvents such as toluene, xylene or chlorobenzene, acetonitrile, propylene glycol monomethyl ether, tetrahydrofuran, dimethoxyethane, ethyl lactate, Chloroform etc. These solvents can be used individually or in combination.

In order to form the alignment film, commercially available alignment film materials can be directly used. Examples of commercially available alignment film materials include SUNEVER (registered trademark, manufactured by Nissan Chemical Co., Ltd.) and OPTOMER (registered trademark, manufactured by JSR Corporation).

If the film is aligned in this way, there is no need to control the refractive index by stretching, so the in-plane inconsistency in birefringence becomes smaller. In addition, it is also possible to provide a large-area retardation film suitable for large-scale image display devices.

The method of forming an alignment film on the aforementioned support base material is, for example, coating a commercially available alignment film material or a solution containing a polymer that becomes an alignment film material on the aforementioned support base material, and then annealing, whereby the alignment film can be formed on the aforementioned support base material. Form an alignment film.

The thickness of the alignment film thus obtained is, for example, 10 nm to 10000 nm, preferably 10 nm to 1000 nm. If it is within the aforementioned range, the polymerizable liquid crystal can be aligned at the desired angle on the alignment film.

In addition, the alignment films may be brushed if necessary. These can be aligned in the desired direction by polymerizable liquid crystals.

The brushing method of the alignment film can be, for example, a method of placing a rotating brushing roller that is wound with a brushing cloth on a platform and in contact with the transported alignment film.

As mentioned above, in the unpolymerized film preparation step, an unpolymerized film (liquid crystal layer) is laminated on the alignment film laminated on the supporting base material. In addition, film production by roll film can be performed.

The solvent may be dried while polymerization is carried out, but from the viewpoint of film-forming properties, it is preferable to dry most of the solvent before polymerization.

Examples of methods for drying the solvent include natural drying, ventilated drying, and reduced pressure drying. The specific heating temperature is preferably 10 to 120°C, more preferably 25 to 80°C. Moreover, the heating time is preferably 10 seconds to 60 minutes, more preferably 30 seconds to 30 minutes. If the heating temperature and heating time are within the aforementioned ranges, a supporting base material with insufficient heat resistance may be used as the supporting base material.

[Unpolymerized film polymerization step]

In the unpolymerized film polymerization step, the polymerizable liquid crystal contained in the unpolymerized film obtained in the aforementioned unpolymerized film preparation step is polymerized and hardened (hereinafter, the polymerization of the polymerizable liquid crystal contained in the unpolymerized film is referred to as "polymerization of the unpolymerized film"). ”). Thereby, a film in which the alignment of the polymeric liquid crystal is fixed is formed, that is, a polymer film is formed. Therefore, it is possible to produce a polymeric film in which the refractive index change in the film plane direction is small and the refractive index change in the normal direction of the film is large.

The method of polymerizing the unpolymerized film may be determined according to the type of polymerizable liquid crystal used. As mentioned above, when the preferred compound (1) is used as the polymerizable liquid crystal, if the polymerizable groups of P ¹ and/or P ² contained in the compound (1) are photopolymerizable, they can be polymerized by photopolymerization. If the sexual group is thermally polymerizable, the unpolymerized film can be polymerized by thermal polymerization. In the present invention, it is particularly preferred to polymerize the unpolymerized film by photopolymerization. The unpolymerized film can be polymerized at low temperature through photopolymerization, so the heat resistance of the support base material can be selected in a wide range. In addition, it is easier to manufacture industrially. In addition, from the viewpoint of film-forming properties, photopolymerization is also preferred. Photopolymerization can be performed by irradiating the unpolymerized film with visible light or ultraviolet light. From the viewpoint of processability, ultraviolet light is particularly preferred. The compound (1) can be irradiated with light while being heated to a temperature at which the compound (1) becomes a liquid crystal phase. At this time, the polymer film can be patterned by masking or the like.

The retardation film obtained by such a manufacturing method has good adhesion to the alignment film, so the retardation film can be easily manufactured.

Furthermore, compared to a stretched film in which a phase difference is imparted by stretching, a phase difference film obtained by using polymerizable liquid crystal has the advantage of being thinner.

In the aforementioned manufacturing method, the step of peeling off the supporting base material may be included after the aforementioned step. By configuring in this manner, the obtained film can be a laminate composed of a supporting base material, an alignment film, and a retardation film. In addition to the step of peeling off the support base material, the method may further include a step of peeling off the alignment film from the laminate. With this configuration, a retardation film without an alignment film can be obtained.

The retardation film thus obtained has excellent transparency and can be used as a film for various image display devices. As mentioned above, the thickness of the formed retardation film varies according to the retardation value of the obtained retardation film.

In the circularly polarizing plate of the present invention, the retardation film containing the liquid crystal material that functions as a λ/4 plate contains foreign matter. Foreign matter is foreign matter that may inevitably be mixed during the manufacturing process, such as foreign matter generated by the liquid crystal compound alignment process, and more specifically, foreign matter (brushing debris) generated by the brushing process. When the retardation film is composed of a stretched film, such foreign matter does not exist. Even if foreign matter is assumed to exist, it is estimated that it will not cause display defects caused by the thickness of the stretched film. As mentioned above, one of the features of the present invention is to prevent the adverse effects of foreign matter that can cause problems (display defects) in a form in which the retardation film is made of a very thin liquid crystal material. Specifically, in a retardation film composed of a liquid crystal material, the actual number of foreign matter may be 100/m ² or more in one embodiment, for example, about 150/m ² to 300/m ² . The average particle size of foreign matter is typically 1.3 μm or less, preferably 0.1 μm to 1.0 μm. In order to achieve such an average particle diameter range, it is preferable to perform the following process: after the brushing process, air or the like is blown on the brushed surface of the alignment film to almost remove foreign matter with a particle size of 3 μm or more. On the other hand, the number of display defects of the circularly polarizing plate according to the embodiment of the present invention is preferably 10/m ² or less, more preferably 8/m ² or less. That is, according to the embodiment of the present invention, even if a large amount of foreign matter is present in the retardation film, most of the foreign matter will be observed as a display defect. In addition, for example, the circular polarizing plate can be observed with an optical microscope (such as a differential interference microscope), thereby confirming and measuring the actual number of foreign matter. For displaying the number of defects, for example, a circular polarizing plate can be placed in an optical microscope, and a circular polarizing plate for inspection using a retardation film composed of a stretched film can be placed as a bright spot in the resulting suspected crossed nicols state. Confirm and measure.

The thickness of the retardation film functioning as a λ/4 plate is 1.5 μm or more, and its surface is substantially flat. The upper limit of the thickness of the retardation film is not particularly limited, but may be 5 μm. By being so thick, The surface can be substantially flat even in the presence of foreign matter. In addition, "substantially flat" in this specification means that there are no protrusions with a height of 0.4 μm or more.

The ratio of the thickness of the retardation film to the average particle diameter of foreign matter is preferably 1.2 or more, more preferably 1.5 to 4.0. If the ratio is within this range, the occurrence of protrusions caused by foreign matter can be reduced, and a substantially flat surface can be satisfactorily realized. As a result, display defects caused by foreign matter can be effectively prevented.

(Second retardation film)

The retardation film used in the present invention can be used in which the aforementioned retardation film is laminated with a second retardation film and integrated. When a laminated body in which a plurality of types of retardation films such as a second retardation film is laminated is used in this way, at least one of the plurality of retardation films constituting the laminated body contains a liquid crystal material and satisfies the aforementioned formulas (α) and Formula (β) and the film thickness is 1.5 μm or more. It is preferable that the 2nd retardation film is produced without performing processes such as brushing treatment or photo-alignment treatment. In this way, the retardation film can suppress the occurrence of display alignment defects, etc., with almost no bright spot defects and no loss of quality. For example, it is preferable that the second retardation film shows the relationship of nz>nx≧ny using refractive index characteristics. By having a second retardation film with such refractive index characteristics, for example, when used as an anti-reflection polarizing plate, the angle dependence of the reflected light absorption effect can be reduced, and the reflected light reflected at various angles can be prevented from being emitted. Better.

In one embodiment, the refractive index of the second retardation film has a relationship of nx=ny. Here, "nx=ny" means not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. Specifically, Re(550) is less than 10 nm.

The Rth (550) of the second retardation film is preferably -260nm to -10nm, more preferably -230nm to -15nm, still more preferably -215nm to -20nm. Such a range is preferable since the above-mentioned effect can be made more remarkable.

The second retardation film can be formed of any appropriate material and is not particularly limited. It is preferably a liquid crystal layer with fixed vertical alignment. The vertically alignable liquid crystal material (liquid crystal compound) can be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method of forming the liquid crystal layer include the liquid crystal compounds and the method of forming them described in Japanese Patent Application Laid-Open No. 2002-333642, [0020] to [0042]. At this time, the thickness is preferably 0.1 μm to 5 μm, more preferably 0.2 μm to 3 μm.

The retardation film on which the second retardation film is laminated also has Re (550) at a wavelength of 550 nm of 90 to 190 nm, preferably 110 to 170 nm, and more preferably 120 to 160 nm. If the Re (550) of the second retardation film is in this range, even if it is laminated with the first retardation film functioning as a λ/4 plate, the retardation film of the laminated body can function as a λ/4 plate.

When integrating the lamination of the second retardation film, any adhesive layer or adhesive layer can be used. The adhesive layer or adhesive layer is, for example, an acrylic adhesive or a rubber-based adhesive formed from a (meth)acrylic polymer as a base polymer. These have excellent optical transparency and show moderate moisture. It is preferred because of its adhesive properties, cohesiveness and adhesion, as well as its excellent weather resistance or heat resistance. Adhesives can be used in various forms such as water-based, solvent-based, hot-melt, and active energy ray-curable adhesives. Water-based adhesives or active energy ray-curable adhesives are preferred. In addition, any known adhesive layer or adhesive layer can also be used.

(circular polarizing plate)

When laminating each layer constituting the circularly polarizing plate of the present invention, any appropriate adhesive (adhesive layer) or adhesive is used. When the polarizing film and the retardation film are laminated, an active energy ray (such as ultraviolet light) curable adhesive or adhesive layer is typically used. The thickness of the adhesive layer is preferably 0.01 μm to 7 μm, more preferably 0.01 μm to 5 μm, and still more preferably 0.01 μm to 2 μm. In addition, the thickness of the adhesive layer is 1 to 30 μm, preferably 3 to 20 μm, and still more preferably 3 to 15 μm.

In the polarizing plate having a polarizing film or a protective film and the retardation film, surface modification treatment such as corona treatment and plasma treatment or treatment to form an easy-adhesion layer may be performed before lamination.

(Construction of circular polarizing plate)

The structure of the circularly polarizing plate of the present invention will be described in more detail.

For example, when using a single-sided protected polarizing plate with a protective film on only one side of the polarizing film, a circular polarizing plate composed of protective film/polarizing film/adhesive layer/retardation film can be formed. In addition, when used in a double-sided protected polarizing plate with protective films on both sides of the polarizing film, a circular polarizing plate composed of protective film/polarizing film/protective film/adhesive layer/retardation film can be formed.

In the aforementioned composition, the angle between the absorption axis of the polarizing film and the slow axis of the retardation film is 35° to 55°, preferably 38° to 52°, more preferably 40° to 50°, and still more preferably 42°. to 48°, the best is 44° to 46°.

If the angle is within this range, the desired circular polarization function can be achieved, so it is preferable. Furthermore, in this specification, when an angle is mentioned, the angle includes both clockwise and counterclockwise angles unless otherwise specified.

The circularly polarizing plate of the present invention may contain an adhesive layer or adhesive layer, an interlayer such as a primer layer (primer layer), or an easy-adhesion layer other than those mentioned above.

In addition, the circularly polarizing plate of the present invention can be provided with a functional layer. The formation of defects such as penetration cracks and nano-slits in the polarizing film can be suppressed by providing a functional layer, so it is preferable. The functional layer can be formed of various forming materials. For example, the functional layer can be formed by coating a resin material on the polarizing film.

Examples of the resin material forming the functional layer include polyester resin, polyether resin, polycarbonate resin, polyurethane resin, polysiloxane resin, polyamide resin, and polyimide. resin, PVA resin, acrylic resin, etc. One type of these resin materials can be used alone or two or more types can be used in combination. Among them, polyurethane-based resins and polyvinyl alcohol (PVA)-based resins are preferred. More than one type selected from the group is preferably a PVA resin. In addition, the form of the resin may be either water-based or solvent-based. The form of the aforementioned resin is preferably a water-based resin, and preferably a PVA-based resin. In addition, an acrylic resin aqueous solution or a urethane resin aqueous solution can be used as the water-based resin.

If the aforementioned functional layer is too thick, the optical reliability and water resistance will be reduced. Therefore, the thickness of the functional layer is preferably 15 μm or less, more preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less, and still more preferably 6 μm or less. More preferably, it is 5 μm or less, and particularly preferably, it is 3 μm or less. On the other hand, the thickness of the functional layer is preferably 0.2 μm or more, more preferably 0.5 μm or more, and still more preferably 0.7 μm or more. It is preferable that the functional layer has this thickness because the occurrence of cracks can be suppressed.

(Circular polarizing plate with adhesive)

The circular polarizing plate of the present invention may be an adhesive-attached circular polarizing plate provided with an adhesive layer on at least any surface. Based on the retardation film, the adhesive layer can be disposed on the side opposite to the polarizing film side. The adhesive used is not particularly limited, and a publicly known adhesive can be used.

The adhesive layer only needs to be one that has excellent optical transparency and exhibits adhesive properties such as moderate wettability, cohesiveness, and adhesion, and is preferably one that has excellent durability in use. Specifically, examples of the adhesive forming the adhesive layer include a pressure-sensitive adhesive composed of an acrylic resin or a rubber-based resin (also called an acrylic adhesive or a rubber-based adhesive).

The adhesive layer formed by the aforementioned acrylic adhesive is not particularly limited. Preferably, butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and (meth)acrylate are used. (meth)acrylate-based resins such as 2-ethylhexyl acrylate, or copolymer resins using two or more types of these (meth)acrylate esters. In addition, polar monomers are copolymerized in these resins. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylamide, and 2-N (meth)acrylate. , N-dimethylaminoethyl ester, and glycidyl (meth)acrylate, etc. have carboxyl groups, hydroxyl groups, Monomers with polar functional groups such as amide group, amine group, and epoxy group. In addition, a cross-linking agent is usually blended with an acrylic resin in an adhesive.

The adhesive can be blended with various other additives. Preferred additives are silane coupling agents or antistatic agents. Silane coupling agent can effectively improve the bonding strength with glass. Antistatic agents can effectively reduce or prevent the generation of static electricity.

Preferably, the thickness of at least one adhesive is 3 to 50 μm. More preferably, it is 3 to 30 μm.

When the adhesive layer is conductive, its resistance value can be appropriately selected, for example, it is preferably in the range of 1×10 ⁹ to 1×10 ¹¹ Ω/□.

The adhesive layer formed on the circular polarizing plate can be formed by a known method.

(Laminated body)

A window film (described later) or a touch sensor (described later) can be laminated on the circularly polarizing plate of the present invention to obtain a laminated body. As the window film, in addition to those mentioned below, glass can also be used. Examples of the laminated body include a laminated body including a circular polarizing plate and a touch sensor, a laminated body including a circular polarizing plate and a window film, or a laminated body including a circular polarizing plate, a touch sensor, and a window film. A laminate with a circular polarizing plate, a touch sensor, and a window film can be laminated with a window film, a touch sensor, and a circular polarizing plate in sequence, or a window film, a circular polarizing plate, and a touch sensor can be laminated in this order. .

(image display device)

The image display device of the present invention includes the circularly polarizing plate or laminate of the present invention. For example, a circularly polarizing plate is laminated on an image display element via the adhesive layer.

Regardless of the type of image display device, a known one can be used. The circularly polarizing plate of the present invention is suitable for use in an organic EL display device, for example. It is particularly suitable for use as an anti-reflective polarizing plate for flexible organic EL display devices.

(Flexible image display device)

The flexible image display device includes a flexible image display device laminate and an organic EL display panel. The flexible image display device laminate is disposed on the viewing side with respect to the organic EL display panel. Constructed in a bendable manner. The laminate for a flexible image display device may contain a window film, a circular polarizing plate, and a touch sensor. The laminating order is arbitrary, but it is preferable to laminate the window film and the circular polarizing plate in order from the visual recognition side. And touch sensor, or window film and touch sensor and circular polarizing plate. If there is a circular polarizing plate on the visual recognition side of the touch sensor, it will be difficult to visually recognize the pattern of the touch sensor, which can make the visual recognition of the displayed image better, so it is better. Individual components can be laminated using adhesives, adhesives, etc.

In addition, any layer of the window film, circular polarizing plate, and touch sensor may be provided with a light-shielding pattern.

(window film)

The window film is placed on the visual recognition side of the flexible image display device, and its role is to protect other necessary components from external impact or environmental changes such as temperature and humidity. In the past, glass was used as such a protective layer, but the window film in the flexible image display device is not rigid and hard like glass, but has flexible characteristics. The aforementioned window film is composed of a flexible transparent base material, and may contain a hard coating layer on at least one side.

The visible light transmittance of the transparent substrate used in the window film is above 70%, preferably above 80%. Any transparent base material can be used as long as it is a transparent polymer film. Specifically, polyolefins such as polyethylene, polypropylene, polymethylpentene, cycloolefin derivatives having monomer units containing norbornene or cycloolefin, cellulose diacetate, and triacetate fiber (modified) cellulose such as cellulose, propyl cellulose, acrylics such as methyl methacrylate (co)polymer, polystyrenes such as styrene (co)polymer, acrylonitrile/butadiene/ Styrene copolymers, acrylonitrile/styrene copolymers, ethylene/vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polyterephthalate Butylene glycol, polyethylene naphthalate, polycarbonate, polyarylate and other polyesters, nylon and other polyamides Classes, polyimides, polyamide imines, polyether imines, polyether sulfides, polysulfides, polyvinyl alcohols, polyvinyl acetals, polyurethane Films formed by polymers such as polymers and epoxy resins. These polymers can be used individually or in mixture of 2 or more types. The polymer film can be any of unstretched, uniaxially or biaxially stretched films. Preferably, among the transparent substrates described above, a polyamide film, a polyamide imine film or a polyimide film, a polyester film, an olefin film, and Acrylic film, cellulose film. Among the polymer films, those in which inorganic particles such as silica, organic fine particles, rubber particles, etc. are dispersed are preferred. In addition, it may contain colorants such as pigments or dyes, fluorescent whitening agents, dispersants, plasticizers, heat stabilizers, light stabilizers, infrared absorbers, ultraviolet absorbers, antistatic agents, antioxidants, slippers, etc. agents, solvents and other admixtures. The thickness of the aforementioned transparent substrate is 5 to 200 μm, preferably 20 to 100 μm.

In the aforementioned window film, a hard coating layer may be provided on at least one side of the transparent substrate. The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 to 100 μm. When the thickness of the hard coat layer is within this range, sufficient scratch resistance is ensured and the bending resistance is excellent. In addition, it can reduce the occurrence of curl caused by hardening shrinkage.

The aforementioned hard coating layer can be formed by hardening a hard coating composition containing a reactive material that is irradiated with active energy rays or thermal energy to form a cross-linked structure. Among them, those hardened by active energy rays are preferred. Active energy rays are defined as energy rays that can decompose compounds that produce active species and produce active species. Examples of active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays, electron rays, and the like. Particularly preferred is ultraviolet light. The hard coat composition contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound.

The aforementioned radically polymerizable compound is a compound having a radically polymerizable group. The radically polymerizable group contained in the radically polymerizable compound may be a functional group capable of generating a radical polymerization reaction, and examples thereof include groups containing a carbon-carbon unsaturated double bond. Specific examples include vinyl, (forma base) acrylyl group, etc. Furthermore, when the radically polymerizable compound is a polymerizable group having two or more radicals, the radically polymerizable groups may be the same or different. From the viewpoint of increasing the hardness of the hard coat layer, the number of radically polymerizable groups per molecule of the radically polymerizable compound is preferably 2 or more. From the viewpoint of high reactivity, among the aforementioned radically polymerizable compounds, compounds having a (meth)acrylyl group are preferred, and compounds having 2 to 6 (meth)acrylyl groups per molecule are preferably used. Compounds of so-called multifunctional acrylate monomers, or so-called epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate have several (meth)acrylates in their molecules. )Oligomers with molecular weights of acrylic groups ranging from hundreds to thousands. Preferably, it contains at least one selected from epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate.

The aforementioned cationically polymerizable compound refers to a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, or a vinyl ether group. From the viewpoint of increasing the hardness of the hard coat layer, the number of cationically polymerizable groups per molecule of the cationically polymerizable compound is preferably 2 or more, and more preferably 3 or more. Among the aforementioned cationically polymerizable compounds, a compound having at least one of an epoxy group and an oxetanyl group as a cationically polymerizable group is preferred. Cyclic ether groups such as epoxy groups and oxetanyl groups are preferable in that they shrink less due to polymerization reaction. In addition, compounds having an epoxy group in a cyclic ether group have the following advantages: they are easily obtained from compounds with various structures, do not adversely affect the durability of the resulting hard coat layer, and are easy to control and radically polymerizable Compound compatibility. In addition, the oxetanyl group in the cyclic ether group has the following advantages: it is easier to increase the degree of polymerization than the epoxy group, has low toxicity, and the resulting hard coat layer has a faster network formation speed from the cationic polymerizable compound. It is fast, and even in the area where it is mixed with a radically polymerizable compound, unreacted monomers do not remain in the film and form an independent network.

Examples of the cationically polymerizable compound having an epoxy group include polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, or a compound containing a cyclohexene ring or a cyclopentene ring with hydrogen peroxide, Alicyclic epoxy resins obtained by epoxidation with appropriate oxidants such as peroxyacid; polyepoxypropyl ethers of aliphatic polyols or their alkylene oxide adducts; polyepoxypropyl esters of aliphatic long-chain polybasic acids , aliphatic epoxy resins such as homopolymers and copolymers of glycidyl (meth)acrylate; bisphenols such as bisphenol A, bisphenol F or hydrogenated bisphenol A, or the addition of these alkylene oxides derivatives such as caprolactone adducts, glycidyl ethers produced by reaction with epichlorohydrin, and glycidyl ethers derived from bisphenols such as novolac epoxy resins. Epoxy resin, etc.

The aforementioned hard coat composition may further contain a polymerization initiator. As the polymerization initiator, a free radical polymerization initiator, a cationic polymerization initiator, a free radical and a cationic polymerization initiator, etc. can be appropriately selected and used. These polymerization initiators can be decomposed by at least one of active energy ray irradiation and heating, and generate free radicals or cations to perform free radical polymerization and cationic polymerization.

The radical polymerization initiator may release a substance that initiates radical polymerization by at least one of active energy ray irradiation and heating. Examples of thermal radical polymerization initiators include hydrogen peroxide, organic peroxides such as perbenzoic acid, azo compounds such as azobisbutyronitrile, and the like.

Active energy ray radical polymerization initiators include Type 1 radical polymerization initiators, which decompose molecules to generate free radicals, and Type 2 radical polymerization initiators, which coexist with tertiary amines and generate free radicals through dehydrogenation reactions. Agents can be used alone or in combination.

The cationic polymerization initiator only needs to be a substance that can be released to start cationic polymerization by at least one of active energy ray irradiation and heating. Examples of the cationic polymerization initiator include aromatic iodonium salts, aromatic sulfonium salts, ferrocene(II) complexes, and the like. Depending on the structure, these can start cationic polymerization by either or both of active energy ray irradiation or heating. The polymerization initiator may be contained in an amount of 0.1 to 10% by weight based on 100% by weight of the entire hard coat composition. The content of the aforementioned polymerization initiator does not reach 0.1 weight When it exceeds 10% by weight, it will cause poor adhesion, cracking, and curling due to hardening shrinkage.

The aforementioned hard coating composition may further contain one or more types selected from the group consisting of solvents and additives. The aforementioned solvent is one that can dissolve or disperse the aforementioned polymerizable compound and polymerization initiator. Solvents known in this technical field for hard coating compositions can be used without particular limitation. The aforementioned additives may further contain inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, etc.

(touch sensor)

Touch sensors are used as input means. Various types of touch sensors have been proposed, such as the resistive film method, the surface acoustic wave method, the infrared method, the electromagnetic induction method, and the capacitive method, and any method can be used. Among them, the capacitive method is preferred. The capacitive touch sensor is divided into an active area and an inactive area located at the periphery of the active area. The active area is an area corresponding to the display area (display portion) of the display panel and is an area that senses a user's touch. The inactive area is an area corresponding to the non-display area (non-display portion) of the display device. The touch sensor may include a flexible substrate, a sensing pattern formed in an active area of the substrate, and an inactive area formed in the substrate and connected to an external driving circuit through the sensing pattern and pad. of each sensing line. The substrate with flexible characteristics can use the same material as the transparent substrate of the aforementioned window film. From the perspective of suppressing breakage of the touch sensor, the substrate of the touch sensor is preferably one with a toughness of 2,000MPa% or more. More preferably, the toughness is 2,000MPa% to 30,000MPa%.

The sensing pattern may include a first pattern formed in the first direction and a second pattern formed in the second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer. In order to sense the touch point, the individual patterns must be electrically connected. The first pattern is a form in which the unit patterns are connected to each other through joint points, and the second pattern is a form in which the unit patterns are separated from each other in an island form. Therefore, in order to electrically connect the second pattern, an additional bridge electrode is required. Known transparent electrode materials can be used for sensing patterns. Examples include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), PEDOT (poly(3,4) -ethylenedioxythiophene), carbon nanotubes (CNT), graphene, metal wires, etc. These can be used alone or two or more types can be mixed and used. It is better to use ITO. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, tellurium, and chromium. These can be used individually or in mixture of 2 or more types.

The bridge electrode may be formed on the upper part of the insulating layer via an insulating layer on the sensing pattern. The bridging electrode may be formed on the substrate and the insulating layer and the sensing pattern may be formed thereon. The aforementioned bridge electrode can be formed of the same material as the sensing pattern, and can be formed of metals such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or alloys of two or more of these. The first pattern and the second pattern must be electrically insulated, so an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the bonding point of the first pattern and the bridge electrode, or may be formed in a layer structure covering the sensing pattern. In the latter case, the bridge electrode can be connected to the second pattern through the contact hole formed in the insulating layer. In the aforementioned touch sensor, the difference in transmittance between the patterned area and the non-patterned area without pattern is specifically the difference in light transmittance caused by the difference in refractive index in these areas. As a means to appropriately compensate for the transmittance difference, an optical adjustment layer may be further included between the substrate and the electrode. The optical adjustment layer may include an inorganic insulating material or an organic insulating material. A photocurable composition containing a photocurable organic binder and a solvent can be coated on the substrate to form an optical adjustment layer. The aforementioned photocurable composition may further contain inorganic particles. The refractive index of the optical adjustment layer can be increased by the aforementioned inorganic particles.

The photocurable organic adhesive may contain, for example, copolymers of monomers such as acrylate monomers, styrene monomers, and carboxylic acid monomers. The aforementioned photocurable organic adhesive may, for example, contain A copolymer of repeating units that are different from each other, such as epoxy repeating units, acrylate repeating units, and carboxylic acid repeating units. The inorganic particles may include, for example, zirconium dioxide particles, titanium dioxide particles, alumina particles, and the like. The aforementioned photocurable composition may further contain various additives such as photopolymerization initiator, polymerizable monomer, and curing auxiliary agent.

Each layer (window film, circular polarizing plate, touch sensor) forming the laminate for a flexible image display device can be laminated using an adhesive. Water-based adhesives, organic solvent-based adhesives, solvent-free adhesives, solid adhesives, solvent evaporative adhesives, moisture-hardening adhesives, heat-hardening adhesives, anaerobic hardening types, and active energy ray-hardening adhesives can be used as adhesives. Type adhesives, hardener mixed adhesives, hot melt adhesives, pressure sensitive adhesives (adhesives), rewetting adhesives, etc. Among them, water-based adhesives, active energy ray-hardening adhesives, and adhesives are more commonly used. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesion force, etc., and is 0.01 μm to 500 μm, preferably 0.1 μm to 300 μm. There are a plurality of the aforementioned laminates for flexible image display devices, but individual thicknesses The types can be the same or different.

(Blackout pattern)

The aforementioned light-shielding pattern may be used as at least part of a light-shielding screen or housing of a flexible image display device. The wiring arranged at the edge of the flexible image display device is hidden by the light shielding pattern, making it difficult to visually recognize, thereby improving the visibility of the image. The aforementioned light-shielding pattern may be in the form of a single layer or multiple layers. The color of the light-shielding pattern is not particularly limited and can be in various colors such as black, white, and metallic colors. The light-shielding pattern can be formed by pigments used to express colors, and polymers such as acrylic resin, ester resin, epoxy resin, polyurethane, and polysiloxane. These can be used individually or in mixture of 2 or more types. The aforementioned light-shielding pattern can be formed by various methods such as printing, photolithography, and inkjet. The thickness of the light shielding pattern may be 1 μm to 100 μm, preferably 2 μm to 50 μm. Furthermore, it is preferable to provide a shape such as an inclination in the thickness direction of the light pattern.

(Example)

The following examples are disclosed to further illustrate the present invention in detail, but the present invention is not limited to these examples. In the examples, parts and % indicating content or usage amount are based on weight unless otherwise specified. In addition, in the following examples, each physical property was measured by the following method.

(1) Determination of thickness:

Measurement was performed using a digital micrometer "MH-15M" manufactured by Nikon Co., Ltd.

(2) Determination of in-plane retardation and thickness direction retardation:

The in-plane retardation and thickness direction retardation at each wavelength were measured at a temperature of 23°C using a phase difference meter "KOBRA (registered trademark)-WPR" manufactured by Oji Measuring Instruments Co., Ltd. based on the parallel polarizer rotation method.

(3) Actual number of foreign objects

The circular polarizing plates obtained in Examples and Comparative Examples were observed using a differential interference microscope (OLYMPUS LG-PS2) at a magnification of 50 times, and the number of confirmed foreign matters was measured.

(4) Display the number of defects

The number of defects was observed using a digital optical microscope (digital microscope VHX-500 manufactured by Keyence Co., Ltd.) at a magnification of 100 times. Specifically, the circularly polarizing plates obtained in Examples and Comparative Examples were placed on a microscope, and the circularly polarizing plate produced in Production Example 5 described later was placed as a polarizing plate for inspection, and the observation was performed in a state that resembled a crossed polarizer. The number of observed bright spots is the number of displayed defects.

[Manufacturing Example 1] Production of polarizing film

A polyvinyl alcohol film with a thickness of 30 μm (average polymerization degree of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched to about 4 times by dry stretching, and further immersed in pure water at 40°C for 40 seconds while maintaining tension. , immersed in an aqueous solution with a weight ratio of iodine/potassium iodide/water of 0.052/5.7/100 at 28°C for 30 seconds and carried out Dyeing treatment. Thereafter, the solution was immersed in an aqueous solution with a weight ratio of potassium iodide/boric acid/water of 11.0/6.2/100 at 70° C. for 120 seconds. Then, wash with 8°C pure water for 15 seconds, and then dry at 60°C for 50 seconds while maintaining a tension of 300N, and then dry at 75°C for 20 seconds to obtain a thickness of 12 μm in which the aligned iodine is adsorbed on the polyvinyl alcohol film. Polarizing film.

[Manufacturing Example 2] Preparation of retardation film A

A 2% by mass aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified type, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the alignment film forming composition.

To a mixture of polymerizable liquid crystal compound A and polymerizable liquid crystal compound B shown below at a mass ratio of 90:10, 1.0 part of a leveling agent (F-556; manufactured by DIC Corporation) and a polymerization initiator were added 6 parts of 2-dimethylamino-2-benzyl-1-(4-morpholinylphenyl)butan-1-one ("IRGACURE 369 (Irg369)", manufactured by BASF JAPAN Co., Ltd.).

Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration became 13%, and the mixture was stirred at 80° C. for 1 hour, thereby obtaining a liquid crystal composition.

The polymerizable liquid crystal compound A is produced according to the method described in Japanese Patent Application Laid-Open No. 2010-31223. In addition, the polymerizable liquid crystal compound B is produced according to the method described in Japanese Patent Application Laid-Open No. 2009-173893. The following shows individual molecular structures.

[Polymerizable liquid crystal compound A]

[Polymerizable liquid crystal compound B]

[Manufacturing of a laminate composed of a supporting base material, an alignment film, and an alignment liquid crystal cured film]

After corona treatment was performed on a 50 μm-thick cyclic olefin-based film [manufactured by Japan ZEON Co., Ltd., trade name "ZF-14-50"] as a support base, the alignment film forming composition was applied with a bar coater. It was dried at 60°C for 1 minute and further dried at 80°C for 3 minutes to obtain a film with a thickness of 89 nm.

Then, a brushing treatment is performed on the surface of the obtained film to form an alignment film. The brushing treatment uses a semi-automatic brushing device (trade name: LQ-008 type, manufactured by Changyang Engineering Co., Ltd.), with a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.) with a pressing amount of 0.15 mm, rotation speed 500rpm, 16.7mm/s. Thereafter, compressed air is blown on the brushed surface of the alignment film. In addition, the direction of the brushing treatment is a direction of 45° counterclockwise when viewed from the visual recognition side with respect to the absorption axis direction of the polarizing film when it is bonded to the polarizing film.

Then, use a rod coater to apply the liquid crystal composition to the alignment film, dry it at 120°C for 1 minute, and then use a high-pressure mercury lamp [trade name of USHIO Electric Co., Ltd.: "uniQure VB-15201BY-A"] to irradiate ultraviolet light (nitrogen environment (The cumulative light amount at a wavelength of 365 nm: 500 mJ/cm ² ), thereby forming an alignment liquid crystal cured film, and obtaining a laminate composed of a base material, an alignment film, and a retardation film.

The Re (λ) of the retardation film produced by the above method is bonded to the glass through an adhesive, and then the cycloolefin-based film of the supporting base material is peeled off (the film obtained by peeling off the cycloolefin-based film is called "retardation film"). A") and then perform the measurement. The film thickness of the retardation film A obtained was measured with a laser microscope. The film thickness is 2.1μm. The measurement results of the phase difference value Re(λ) at each wavelength are Re(450)=121nm, Re(550)=142nm, and Re(650)=146nm. Re(550) is in the range of 90 to 190nm and functions as a λ/4 plate. Re(450)/Re(550)=0.85, Re(650)/Re(550)=1.03, which satisfy the relationship of formula (α) and formula (β). In addition, the surface of the retardation film A was confirmed to be substantially flat since no protrusions with a height of 0.4 μm or more were confirmed.

[Manufacturing Example 3] Preparation of retardation film B

A 2% by mass aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000 completely saponified type, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the alignment film forming composition.

Next, 10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF, trade name PaliocolorLC242), and a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name IRGACURE (registered trademark)) for the polymerizable liquid crystal compound were added 907, 0.5 g of a benzotriazole ultraviolet absorber (1%) was dissolved in 40 g of toluene to prepare a liquid crystal composition.

After corona treatment was performed on a 50 μm-thick cyclic olefin-based film [manufactured by Japan ZEON Co., Ltd., trade name "ZF-14-50"] as a support base, the alignment film forming composition was applied with a bar coater. It was dried at 60° C. for 1 minute and further dried at 80° C. for 3 minutes to form a film with a thickness of 95 nm.

Then, a brushing treatment is performed on the surface of the obtained film to form an alignment film. The brushing treatment uses a semi-automatic brushing device (trade name: LQ-008 type, manufactured by Changyang Engineering Co., Ltd.), with a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Chemical Co., Ltd.) with a pressing amount of 0.15 mm, rotation speed 500rpm, 16.7mm/s. In addition, the direction of the brushing treatment is a direction of 45° counterclockwise when viewed from the visual recognition side with respect to the absorption axis direction of the polarizing film when it is bonded to the polarizing film.

Then, the liquid crystal composition was coated on the alignment film using a bar coater, and dried at 100° C. for 1 minute. Then, a high-pressure mercury lamp is used to irradiate ultraviolet light (accumulated light amount at a wavelength of 365 nm in a nitrogen environment: 1200 mJ/cm ² ), thereby forming a retardation film B on the alignment film. The film thickness of the obtained retardation film B was measured with a laser microscope and found to be 973 nm. The phase difference value was measured, Re(550)=135nm, and the alignment angle was 75° relative to the long direction of the aforementioned TAC. Furthermore, the phase difference values at wavelength 450nm and wavelength 650nm were measured, Re(450)=145nm, Re(650)=132nm. Re(450)/Re(550)=1.07, Re(650)/Re(550)=0.98, the relationship between formula (α) and formula (β) is not satisfied. A large number of protrusions with a height of 0.4 μm or more were observed on the surface of retardation film B, which was not substantially flat.

[Manufacture Example 4] Production of second retardation film C

A commercially available vertical alignment film (JALS-204R, manufactured by Japan Synthetic Rubber Co., Ltd.) was diluted 1:1 with methyl ethyl ketone and then coated on the substrate with a wire bar coater (coating amount: 2.4 ml/m ² ). Membrane (cellulose triacetate membrane, thickness 80 μm) surface. Immediately dry with hot air at 120°C for 120 seconds.

Next, 3.8 g of the following rod-shaped liquid crystal compound, 0.06 g of photopolymerization initiator (IRGACURE (registered trademark) 907), 0.02 g of sensitizer (KAYACURE (registered trademark) DETX, manufactured by Nippon Kayaku Co., Ltd.), A solution of 0.002g of the following vertical alignment agent on the air interface side was dissolved in 9.2g of methyl ethyl ketone. The solution is applied with a wire bar on the alignment film side of the film forming the alignment film, and heated at 100° C. for 2 minutes to align the rod-shaped liquid crystal compound. Then, a 120W/cm ² high-pressure mercury lamp was used to irradiate UV for 20 seconds at 80°C to cross-link the rod-shaped liquid crystal compound, and then cooled to room temperature to produce a retardation layer with positive-C plate characteristics. The thickness of the obtained retardation layer was 0.5 μm, and the Rth (550) was -70.3 nm.

Rod-shaped liquid crystal compound

Air interface side vertical alignment agent:

Exemplary compound (II-4) described in Japanese Patent Application No. 2003-119959

[Manufacturing Example 5] Production of circular polarizing plate for inspection

A polyvinyl alcohol-based adhesive was applied to one side of the polarizing film obtained in Production Example 1 so that the adhesive layer thickness became 0.1 μm, and a protective film (triacetylcellulose (TAC) film (trade name: KC2UAW, thickness: 25 μm) was laminated. KONICA MINOLTA Co., Ltd.) and then dried at 80°C for 2 minutes to prepare a polarizing plate with a protective film on one side. The polarizing film side of the obtained polarizing plate with a protective film on one side was separated by an acrylic adhesive (LINTEC Co., Ltd. Co., Ltd. NCF #L2, thickness 5μm) is bonded to a retardation film (stretch film manufactured by Japan ZEON Co., Ltd.; ZD12 series; Re(550)=141nm). Here, the slow axis of the retardation film is relative to the polarizing film The absorption axis is fitted in a 45° clockwise direction.

[Example 1]

A polyvinyl alcohol-based adhesive was applied to one side of the polarizing film obtained in Production Example 1 so that the adhesive layer thickness became 0.1 μm, and a protective film (triacetylcellulose (TAC) film (trade name: KC2UAW, thickness: 25 μm) was laminated , manufactured by KONICA MINOLTA Co., Ltd.) and then dried at 80°C for 2 minutes to prepare a polarizing plate with a protective film on one side.

The retardation film A obtained in Production Example 2 was bonded to the polarizing film side of the obtained polarizing plate with a protective film on one side via an acrylic adhesive (NCF #L2 manufactured by LINTEC, thickness 5 μm). Here, the slow axis of the retardation film is oriented at 45° counterclockwise relative to the absorption axis of the polarizing film. After further peeling off the base film of the retardation film A, an acrylic adhesive (P-3132 manufactured by LINTEC, thickness 25 μm) was obtained. circular polarizing plate. The obtained circularly polarizing plate has a structure composed of TAC film/adhesive layer/polarizing film/acrylic adhesive layer/phase difference film A/acrylic adhesive/separator.

The obtained circular polarizing plate was cut into a size of 100mm×100mm. The obtained circularly polarizing plate was used for the evaluation of the aforementioned (3) and (4). Inspection of 100 pieces of the obtained circular polarizing plates revealed that the actual number of foreign matter in the retardation film A was approximately 200/m ² and the number of defects displayed in the circular polarizing plates was 7/m ² . The foreign matter is polyvinyl alcohol, which is brush debris.

[Example 2]

A polyvinyl alcohol-based adhesive was applied to both sides of the polarizing film obtained in Production Example 1 so that the thickness of the adhesive layer became 0.1 μm, and a protective film (triacetylcellulose (TAC) film (trade name: KC2CT, thickness: 20 μm, KONICA MINOLTA Co., Ltd.) and then dried at 80°C for 2 minutes to prepare a polarizing plate with protective films on both sides.

Evaluation samples were prepared in the same manner, except that the polarizing plate with a protective film on one side of Example 1 was changed to the polarizing plate with protective films on both sides. The obtained circularly polarizing plate has a structure composed of TAC film/adhesive layer/polarizing film/adhesive layer/TAC film/acrylic adhesive layer/retardation film A/acrylic adhesive/separator.

The obtained circular polarizing plate was cut into a size of 100mm×100mm. The obtained circularly polarizing plate was used for the evaluation of the aforementioned (3) and (4). After inspecting 100 pieces of the obtained circular polarizing plates, it was found that the actual number of foreign matter in the retardation film was about 200 pieces/m ² and the number of defects displayed in the circular polarizing plates was 6 pieces/m ² . The foreign matter is polyvinyl alcohol, which is brush debris.

[Example 3]

A polyvinyl alcohol-based adhesive was applied to one side of the polarizing film obtained in Production Example 1 so that the thickness of the adhesive layer became 0.1 μm, and a protective film (triacetylcellulose (TAC) film (trade name: KC2UAW, thickness: 25 μm, manufactured by KONICA MINOLTA Co., Ltd.) and then dried at 80°C for 2 minutes to prepare a polarizing plate with a protective film on one side.

The retardation film A obtained in Production Example 2 was bonded to the polarizing film side of the obtained polarizing plate with a protective film on one side via an acrylic adhesive (NCF #L2 manufactured by LINTEC, thickness 5 μm). Here, the slow axis of the retardation film is oriented at 45° counterclockwise relative to the absorption axis of the polarizing film. After further peeling off the base film of the retardation film A, the retardation film C obtained in Production Example 4 was bonded via an acrylic adhesive (NCF #L2 manufactured by LINTEC, thickness 5 μm). Finally, after peeling off the base film of the retardation film C, a circular polarizing plate laminated with an acrylic adhesive (P-3132 manufactured by LINTEC, thickness 25 μm) was obtained. The obtained circularly polarizing plate has a structure composed of TAC film/adhesive layer/polarizing film/adhesive layer/retardation film A/acrylic adhesive/retardation film C/acrylic adhesive/separator.

The obtained circular polarizing plate was cut into a size of 100mm×100mm. The obtained circularly polarizing plate was used for the evaluation of the aforementioned (3) and (4). Inspection of 100 pieces of the obtained circular polarizing plates revealed that the actual number of foreign matter in the retardation film A was approximately 200/m ² and the number of defects displayed in the circular polarizing plates was 7/m ² . The foreign matter is polyvinyl alcohol, which is brush debris.

[Comparative example 1]

A circularly polarizing plate was produced in the same manner except that the retardation film A of Example 1 was changed to the retardation film B obtained in Production Example 3.

The obtained circular polarizing plate was cut into a size of 100mm×100mm. The obtained circularly polarizing plate was used for the evaluation of the aforementioned (3) and (4). After inspecting 100 pieces of the obtained circular polarizing plates, it was found that the actual number of foreign matter in the retardation film was about 200 pieces/m ² and the number of displayed defects in the circular polarizing plates was 168 pieces/m ² . The foreign matter is polyvinyl alcohol, which is brush debris.

(industrial applicability)

According to the present invention, a circular polarizing plate can be obtained, which is very thin, has excellent anti-reflection properties, and suppresses the adverse effects of foreign matter on the display performance of the image display device, so it has industrial applicability.

Claims (7)

A circularly polarizing plate, which is provided with a polarizing film and a retardation film functioning as a λ/4 plate in sequence, the angle between the absorption axis of the polarizing film and the slow axis of the retardation film is 35° to 55°, and the phase The retardation film contains a liquid crystal material, and the aforementioned retardation film satisfies the following formulas (α) and (β), Re(450)/Re(550)≦1.00 (α), 1.00≦Re(650)/Re(550) (β) , the aforementioned retardation film contains foreign matter, the thickness of the aforementioned retardation film is 1.5 μm or more, the number of the aforementioned foreign matters is 150 pieces/m ² to 300 pieces/m ² , and the surface of the aforementioned retardation film is substantially flat, where, Re (450) represents the in-plane phase difference value at a wavelength of 450 nm, Re(550) represents the in-plane phase difference value at a wavelength of 550 nm, and Re(650) represents the in-plane phase difference value at a wavelength of 650 nm. For the circular polarizing plate described in Item 1 of the patent application, the foreign matter is brush scraps. The circularly polarizing plate described in claim 1 or 2, wherein the ratio of the thickness of the retardation film to the average particle diameter of the foreign matter is 1.2 to 4.0. A laminated body includes the circular polarizing plate described in any one of items 1 to 3 of the patent application scope, and a touch sensor. An image display device is provided with the circular polarizing plate described in any one of items 1 to 3 of the patent application scope. An image display device having the laminated body described in Item 4 of the patent application. The image display device according to claim 5 or 6, wherein the image display device is an organic electroluminescent display device.