WO2020044750A1

WO2020044750A1 - Circularly polarizing plate and image display device using same

Info

Publication number: WO2020044750A1
Application number: PCT/JP2019/024884
Authority: WO
Inventors: 寿和松本
Original assignee: 住友化学株式会社
Priority date: 2018-08-31
Filing date: 2019-06-24
Publication date: 2020-03-05
Also published as: TWI820171B; CN112639552A; TW202032167A; JPWO2020044750A1; KR20210049798A

Abstract

A circularly polarizing plate provided with a polarizing film and a retardation film for functioning as a λ/4 plate, in this order, the angle formed by the absorption axis of the polarizing film with the slow axis of the retardation film being 35° to 55°, the retardation film including a liquid crystal material, the retardation film satisfying expressions (α) and (β) ((α): Re(450)/Re(550) ≤ 1.00; (β): 1.00 ≤ Re(650)/Re(550)), the retardation film including an impurity, the thickness of the retardation film being 1.5 µm or greater, and the surface of the retardation film being essentially flat.

Description

Circularly polarizing plate and image display device using the same

{Circle around (1)} The present invention relates to a circularly polarizing plate and an image display device using the same.

In recent years, mobile phones and tablet terminals have become widespread, and liquid crystal display devices and organic electroluminescent display devices (organic EL display devices) have been widely used as image display devices. Generally, in an organic EL display device, a circularly polarizing plate is disposed on a viewing side surface of an organic EL panel in order to prevent external light from being reflected by a metal electrode (cathode) and being viewed like a mirror surface. In addition, the display device is demanded from the market to be thin. Therefore, in a display device that needs to be thin, it is preferable that each member such as a polarizing plate and a circularly polarizing plate used in the display device is also thin.

積層 Generally, a laminate of a polarizing plate and a λ / 4 plate is used as the circularly polarizing plate. As a circularly polarizing plate, for example, a plate in which a polarizing film and one retardation layer having specific refractive index characteristics are laminated is also known (for example, see Patent Document 1).

The retardation film is generally a stretched film produced by stretching a resin film, but there is a limit to thinning a λ / 4 plate using this stretched film. Therefore, a λ / 4 plate using a layer in which a polymerizable liquid crystal compound is cured has been proposed for further reduction in thickness (for example, see Patent Document 2). However, in a circularly polarizing plate having such a λ / 4 plate, foreign matter may be mixed depending on the manufacturing process, and this foreign matter (a λ / 4 plate formed of a resin film does not cause a problem. ) Becomes a bright spot, which may adversely affect display characteristics. In addition, there may be a problem that the manufacturing yield is reduced. Such an effect is even greater in a circularly polarizing plate using a λ / 4 plate using a layer in which a polymerizable liquid crystal compound having an inverse wavelength dispersion property with respect to a retardation value is cured. This is because the antireflection effect can be obtained in a wider band of wavelengths, so that the bright spot tends to be easily recognized.

Japanese Patent No. 3325560 JP 2014-123134 A

The present invention has been made to solve the above-mentioned conventional problems, and its main objects are to be extremely thin, have excellent anti-reflection characteristics, and adversely affect the display performance of an image display device due to foreign matter. Is to provide a circularly polarizing plate in which is suppressed.

That is, the present invention provides the following circularly polarizing plate and image display device.
[1] A polarizing film and a retardation film functioning as a λ / 4 plate are provided in this order, and an angle between an absorption axis of the polarizing film and a slow axis of the retardation film is 35 ° to 55 °. ,
The retardation film includes a liquid crystal material,
The retardation film satisfies the following formulas (α) and (β);
Re (450) / Re (550) ≦ 1.00 (α)
1.00 ≦ Re (650) / Re (550) (β)
The retardation film contains foreign matter,
The thickness of the retardation film is 1.5 μm or more,
A circularly polarizing plate, wherein the surface of the retardation film is substantially flat.
[Wherein, Re (450) represents an in-plane retardation value at a wavelength of 450 nm, Re (550) represents an in-plane retardation value at a wavelength of 550 nm, and Re (650) represents an in-plane retardation value at a wavelength of 650 nm. Represent. ]
[2] The circularly polarizing plate according to [1], wherein the foreign matter is rubbing waste.
[3] A laminate comprising the circularly polarizing plate according to [1] or [2] and a touch sensor.
[4] An image display device having the circularly polarizing plate according to [1] or [2].
[5] An image display device having the laminate 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, it is possible to obtain a circularly polarizing plate that is extremely thin, has excellent antireflection properties, and suppresses adverse effects on display performance of an image display device due to foreign matter.

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

(Definition of terms and symbols)
Definitions of terms and symbols in this specification are as follows.
(1) Refractive index (nx, ny, nz)
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), “ny” is the direction perpendicular to the slow axis in the plane, and “nz” is the thickness direction. It is a refractive index.
(2) In-plane retardation value The in-plane retardation value (Re (λ)) refers to the in-plane retardation value of a film at a temperature of 23 ° C. and a wavelength of λ (nm). Re (λ) is determined by Re (λ) = (nx−ny) × d, where d (nm) is the thickness of the film.
(3) Retardation Value in Thickness Direction The in-plane retardation value (Rth (λ)) refers to the retardation value in the thickness direction of the film at a temperature of 23 ° C. and a wavelength of λ (nm). Rth (λ) is determined by Rth (λ) = ((nx + ny) / 2−nz) × d, where d (nm) is the thickness of the film.

(Polarizing film)
The polarizing film is not particularly limited, and various types can be used. Examples of the polarizing film include, for example, a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, a hydrophilic polymer film such as an ethylene-vinyl acetate copolymer-based partially saponified film, and dichroic properties of iodine and a dichroic dye. Examples thereof include a uniaxially stretched material obtained by adsorbing (dying) a substance, and a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizing film composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizing films is not particularly limited, but is generally about 3 to 80 μm. The thickness of a polarizing film applied to a display device that requires a reduction in thickness is preferably 15 μm or less.

As the polyvinyl alcohol-based film, a film obtained by saponifying a polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of another monomer copolymerizable with vinyl acetate, and the like. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

A film formed of a polyvinyl alcohol-based resin is used as a raw film of a polarizing film. As a method for forming a polyvinyl alcohol-based resin, a known method can be used. The film thickness of the raw polyvinyl alcohol resin film is preferably about 5 to 35 μm, more preferably 5 to 20 μm, considering that the thickness of the obtained polarizing film is 15 μm or less. If the thickness of the raw film exceeds 35 μm, it is necessary to increase the stretching ratio when producing a polarizing film, and the dimensional shrinkage of the obtained polarizing film tends to increase. On the other hand, when the film thickness of the raw film is less than 5 μm, the handleability at the time of stretching is reduced, and defects such as cutting during production tend to occur easily.

の一 Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing the dichroic dye. When the uniaxial stretching is performed after the dyeing, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. In addition, uniaxial stretching may be performed in these plural stages. The boric acid treatment plays a role of crosslinking the dyed polyvinyl alcohol-based resin film.

In uniaxial stretching, uniaxial stretching may be performed between rolls having different peripheral speeds, or uniaxial stretching may be performed using a hot roll. The uniaxial stretching may be dry stretching in which stretching is performed in the atmosphere, or wet stretching in which a polyvinyl alcohol-based resin film is stretched in a solvent (eg, water) while being stretched. . The stretching ratio is usually about 3 to 8 times.

(4) As a method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye is employed. As the dichroic dye, specifically, iodine or a dichroic dye is used. The polyvinyl alcohol-based resin film is preferably subjected to a dipping treatment in water before the dyeing treatment.

When iodine is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide and dyeing the same is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water. Further, the content of potassium iodide 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 about 20 to 40 ° C.
The immersion time (dyeing time) in the aqueous solution is usually about 20 to 1,800 seconds.

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

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

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

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

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

By the drying treatment, the moisture content of the polarizing film is reduced to a practical level. The water content is usually 5 to 20% by weight, preferably 8 to 15% by weight. When the water content is less than 5% by weight, the flexibility of the polarizing film is lost, and the polarizing film may be damaged or broken after drying. When the water content exceeds 20% by weight, the thermal stability of the polarizing film may be poor.

Further, the stretching, dyeing, boric acid treatment, washing step, and drying step of the polyvinyl alcohol-based resin film in the polarizing film production step may be performed according to, for example, the method described in JP-A-2012-159778. . In the method described in this document, a polyvinyl alcohol-based resin layer serving as a polarizing film is formed by coating a polyvinyl alcohol-based resin on a base film.

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

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 a double-sided protective polarizing plate having a protective film on both sides of the polarizing film.

The polarizing film may be a liquid crystal coating type polarizing film obtained by applying a composition containing a liquid crystal compound. The composition containing a liquid crystal compound can contain a liquid crystal compound and a dichroic dye. The liquid crystal compound only needs to have the property of exhibiting a liquid crystal state, and in particular, it is preferable to have a higher order alignment state such as a smectic phase since high polarization performance can be exhibited. Further, the liquid crystal compound preferably has a polymerizable functional group. The dichroic dye is a dye that exhibits dichroism when aligned with a liquid crystal compound, and the dichroic dye itself may have liquid crystallinity or may have a polymerizable functional group. it can. Any of the compounds in the composition including the liquid crystal compound has a polymerizable functional group. The composition containing the liquid crystal compound can further contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The liquid crystal coating type polarizing film can be manufactured by applying a composition containing a liquid crystal compound on an alignment film and curing the composition. The liquid crystal coating type polarizing film can be formed to be thinner than a film type polarizing film (a polarizing film formed from a polyvinyl alcohol-based resin film). The thickness of the liquid crystal coating type polarizing film may be 0.5 to 5 μm, preferably 1 to 4 μm.

(Protective film)
As a material for forming the protective film provided on one or both surfaces of the polarizing film, a material having excellent transparency, mechanical strength, heat stability, moisture blocking property, isotropy, and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Polymers, polycarbonate polymers and the like. In addition, polyethylene, polypropylene, polyolefin having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene-propylene copolymer, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamide, imide-based polymers, and sulfone-based polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or Blends of the above-mentioned polymers are also examples of the polymer forming the protective film. The protective film can also be formed as a cured layer of a thermosetting or ultraviolet curable resin such as an acrylic, urethane, acrylic urethane, epoxy or silicone resin. When a protective film is provided on both sides of the polarizing film, a protective film made of the same polymer material may be used on both sides thereof, or a protective film made of a different polymer material or the like may be used.

(4) The thickness of the protective film is generally about 1 to 100 μm from the viewpoint of workability such as strength and handleability and thinness. Preferably, it is 5 to 80 μm, more preferably 5 to 50 μm.

The polarizing film and the protective film are usually laminated via an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester. In addition to the above, examples of the adhesive between the polarizing film and the protective film include an ultraviolet curable adhesive and an electron beam curable adhesive. The electron beam-curable adhesive exhibits suitable adhesiveness to the various protective films. The protective film and the polarizing film are preferably subjected to a saponification treatment, a corona treatment, a plasma treatment or the like before the lamination with the polarizing film.

The surface of the protective film on which the polarizing film is not adhered may be subjected to a hard coat layer, an antireflection treatment, an antistatic layer, an anti-sticking layer, and a treatment for diffusion or antiglare.

The protective film used on the side of the polarizing film on which the retardation film is not laminated may, if necessary, be processed to improve the visibility when viewed through polarized sunglasses (typically, circularly polarized light (or elliptically polarized light)). Imparting a function or imparting a super-high retardation). By performing such a process, excellent visibility can be realized even when the display screen is viewed through a polarizing lens such as polarized sunglasses. Therefore, the circularly polarizing plate can be suitably applied to an image display device that can be used outdoors.

保護 Further, the protective film used between the polarizing film and the retardation film is preferably optically isotropic. As used herein, “optically isotropic” means that Re (550) is 0 nm to 10 nm and Rth (550) is −20 nm to +20 nm.

(Retardation film functioning as 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. Re (550) of the retardation film at a wavelength of 550 nm is from 90 to 190 nm, preferably from 110 to 170 nm, more preferably from 120 to 160 nm.

The retardation film contains a liquid crystal material. The term “including a liquid crystal material” is a concept that includes a liquid crystal material that can form a liquid crystal layer, and includes a cured product obtained by using a liquid crystal material and curing the liquid crystal material in a liquid crystal state by a polymerization reaction or the like. By using a liquid crystal material, the difference between nx and ny of the obtained retardation layer can be much larger than that of a non-liquid crystal material. As a result, the thickness of the retardation layer for obtaining a desired in-plane retardation value can be remarkably reduced, which can contribute to thinning of the obtained circularly polarizing plate and image display device. Further, roll-to-roll becomes possible in the production of the circularly polarizing plate, and the production process can be remarkably reduced. Details will be described later.

The liquid crystal material is preferably capable of forming a nematic liquid crystal phase (nematic liquid crystal). The mechanism for developing the liquid crystal properties of the liquid crystal material may be lyotropic or thermotropic. The alignment state of the liquid crystal material is preferably a homogeneous alignment. The liquid crystal material may be used alone or in combination of two or more.

The retardation film is preferably a cured layer of a liquid crystal material. Specifically, the liquid crystal material is preferably a polymerizable monomer and / or a crosslinkable monomer. Hereinafter, the liquid crystal material of the polymerizable monomer or the crosslinkable monomer may be referred to as “polymerizable liquid crystal”. The polymerizable liquid crystal can be fixed by polymerizing or crosslinking the polymerizable liquid crystal. After the polymerizable liquid crystal is aligned, for example, by polymerizing or crosslinking the polymerizable liquid crystal, the alignment state can be fixed. Here, a polymer is formed by polymerization, and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystalline. Therefore, the formed retardation film does not undergo a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change specific to a liquid crystal compound such as a polymerizable liquid crystal. The retardation film obtained as a result can be a layer having excellent stability, which is not affected by a change in temperature.

層 In order for a layer formed by polymerizing the polymerizable liquid crystal to exhibit an in-plane retardation, the polymerizable liquid crystal may be oriented in a suitable direction. When the polymerizable liquid crystal is rod-shaped, an in-plane retardation is developed by orienting the optical axis of the polymerizable liquid crystal horizontally with respect to the substrate plane. In this case, the optical axis direction coincides with the slow axis direction. When the polymerizable liquid crystal is disc-shaped, an in-plane retardation is developed by orienting the optical axis of the polymerizable liquid crystal horizontally with respect to the substrate plane. In this case, 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 combining the alignment film with the polymerizable liquid crystal.

In the present invention, a retardation film having optical properties represented by the formulas (α) and (β) can be obtained by using a cured layer of a polymerizable liquid crystal described below. In order to exhibit such optical characteristics, two or more retardation films may be laminated to form the retardation film of the circularly polarizing plate of the present invention. When two or more retardation films are used, one or more retardation films among them need only contain 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 described above, the polymerizable liquid crystal is a liquid crystal material having a polymerizable group. The polymerizable group means a group participating in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, an oxetanyl group, and the like. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystallinity of the polymerizable liquid crystal may be a thermotropic liquid crystal or a lyotropic liquid crystal. When the thermotropic liquid crystal is classified according to the degree of order, it may be a nematic liquid crystal or a smectic liquid crystal.

For example, the polymerizable liquid crystal used in the present invention is a compound represented by the following formula (1) (hereinafter, may be referred to as “compound (1)”) because it can exhibit preferable optical characteristics.

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 ) ₁ -F ² -P ² ( 1)

[In the 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, and π electrons contained in the aromatic ring in the Ar group. the number N _[pi of 12 or more.
D ¹ and D ² are each independently * -O-CO- (* indicates a position bonding 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 represents -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 atom contained in the alicyclic hydrocarbon group may be a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group. The methylene group contained in the alicyclic hydrocarbon group may be substituted, and may be substituted with —O—, —S—, or —NH—.
^E ^{^1,} E 2, ^B ¹ and ^{B 2} are each ^{^{_{_{independently, -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 a 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 atom contained in the divalent alicyclic hydrocarbon group and the divalent aromatic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group. It may be substituted by a group. The hydrogen atom 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 a fluorine atom.
k and l each independently represent an integer of 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 -O — Or —CO— may be substituted.
P ¹ and P ² each independently represent a hydrogen atom or a polymerizable group (provided that at least one of P ¹ and P ² represents a polymerizable group). ]

The compound (1) preferably satisfies the requirements represented by the formulas (2) and (3).
(N _π- 4) / 3 <k + 1 + 4 (2)
12 ≦ N _π ≦ 22 (3)
[In the formulas (2) and (3), N _π , k and l represent the same meaning as described above. ]

Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthroline ring. Examples of the aromatic heterocycle include a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, a benzothiazole ring, and the like. Among these, a benzene ring, a thiazole ring and a 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, and the total of π electrons of the aromatic ring contained in the divalent group. The number N _π is 12 or more, preferably 12 or more and 22 or less, and more preferably 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 an aromatic hydrocarbon ring and an aromatic heterocyclic ring.

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

[In the formulas (Ar-1) to (Ar-13), Z ¹ represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 6 carbon atoms, Alkylsulfonyl group having 1 to 6 carbon atoms, fluoroalkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, alkylthio group having 1 to 6 carbon atoms, N-alkylamino group having 1 to 6 carbon atoms Represents an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 6 carbon atoms, or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.
Q ¹ and Q ³ each 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 optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.
W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group, or a halogen atom.
m represents an integer of 0 to 6.
n represents an integer of 0 to 2. ]

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

アルキル Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. Among them, an alkyl group having 1 to 4 carbon atoms is preferable, an alkyl group having 1 to 2 carbon atoms is more preferable, and a methyl group is particularly preferable.

Examples of the alkylsulfinyl group having 1 to 6 carbon atoms include methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, butylsulfinyl, isobutylsulfinyl, sec-butylsulfinyl, tert-butylsulfinyl, pentylsulfinyl Group, hexyl group sulfinyl and the like. Among them, an alkylsulfinyl group having 1 to 4 carbon atoms is preferable, an alkylsulfinyl group having 1 to 2 carbon atoms is more preferable, and a methylsulfinyl group is particularly preferable.

Examples of the alkylsulfonyl group having 1 to 6 carbon atoms include methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, pentylsulfonyl Group, hexylsulfonyl group and the like. Among them, an alkylsulfonyl group having 1 to 4 carbon atoms is preferable, an alkylsulfonyl group having 1 to 2 carbon atoms is more preferable, and a methylsulfonyl group is particularly preferable.

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

Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, and a hexyloxy group. Can be Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, an alkoxy group having 1 to 2 carbon atoms is more preferable, and a methoxy group is particularly preferable.

Examples of the alkylthio group having 1 to 6 carbon atoms include a methylthio group, an ethylthio group, a propylthio group, an isopropylthio group, a butylthio group, an isobutylthio group, a sec-butylthio group, a tert-butylthio group, a pentylthio group, and a hexylthio group. . Among them, an alkylthio group having 1 to 4 carbon atoms is preferable, an alkylthio group having 1 to 2 carbon atoms is more preferable, and a methylthio group is particularly preferable.

The N-alkylamino group having 1 to 6 carbon atoms includes N-methylamino group, N-ethylamino group, N-propylamino group, N-isopropylamino group, N-butylamino group, N-isobutylamino group, Examples include an N-sec-butylamino group, an N-tert-butylamino group, an N-pentylamino group, an N-hexylamino group, and the like. Among them, an N-alkylamino group having 1 to 4 carbon atoms is preferable, an N-alkylamino group having 1 to 2 carbon atoms is more preferable, and an N-methylamino group is particularly preferable.

The N, N-dialkylamino group having 2 to 12 carbon atoms includes N, N-dimethylamino group, N-methyl-N-ethylamino group, N, N-diethylamino group, N, N-dipropylamino group, N, N-diisopropylamino group, N, N-dibutylamino group, N, N-diisobutylamino group, N, N-dipentylamino group, N, N-dihexylamino group and the like. Among them, an N, N-dialkylamino group having 2 to 8 carbon atoms is preferable, an N, N-dialkylamino group having 2 to 4 carbon atoms is more preferable, and an N, N-dimethylamino group is particularly preferable.

Examples of the N-alkylsulfamoyl group having 1 to 6 carbon atoms include N-methylsulfamoyl, N-ethylsulfamoyl, N-propylsulfamoyl, N-isopropylsulfamoyl, N- Butylsulfamoyl, N-isobutylsulfamoyl, N-sec-butylsulfamoyl, N-tert-butylsulfamoyl, N-pentylsulfamoyl, N-hexylsulfamoyl, etc. Is mentioned. Among them, an N-alkylsulfamoyl group having 1 to 4 carbon atoms is preferable, an N-alkylsulfamoyl group having 1 to 2 carbon atoms is more preferable, and an N-methylsulfamoyl group is particularly preferable.

Examples of the N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms include N, N-dimethylsulfamoyl, N-methyl-N-ethylsulfamoyl, N, N-diethylsulfamoyl, N, N-dipropylsulfamoyl, N, N-diisopropylsulfamoyl, N, N-dibutylsulfamoyl, N, N-diisobutylsulfamoyl, N, N-dipentylsulfamoyl, And N, N-dihexylsulfamoyl group. Among them, an N, N-dialkylsulfamoyl group having 2 to 8 carbon atoms is preferable, an N, N-dialkylsulfamoyl group having 2 to 4 carbon atoms is more preferable, and an N, N-dimethylsulfamoyl group is particularly preferable. .

Z ¹ is a halogen atom, methyl group, cyano group, nitro group, carboxyl group, methylsulfonyl group, trifluoromethyl group, methoxy group, methylthio group, N-methylamino group, N, N-dimethylamino group, N- It is preferably a methylsulfamoyl group or an N, N-dimethylsulfamoyl group.

Examples of the alkyl group having 1 to 4 carbon atoms for R ⁷ and R ⁸ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group and a tert-butyl group. Among them, an alkyl group having 1 to 2 carbon atoms is preferable, and a methyl group is more preferable.
Q ¹ is preferably -S-, -CO-, -NH-, -N (CH ₃ )-, and Q ³ is preferably -S-, -CO-.

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group and a biphenyl group. Among them, a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable. The aromatic heterocyclic group includes at least one nitrogen atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, a benzothiazolyl group, and a hetero atom such as an oxygen atom and a sulfur atom, and has 4 to 20 carbon atoms. And a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, and a thiazolyl group are preferred.

The aromatic hydrocarbon group and the 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, An alkylsulfinyl group having 1 to 6 carbon atoms, an alkylsulfonyl group having 1 to 6 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms N-alkylamino group having 1 to 6 carbon atoms, N, N-dialkylamino group having 2 to 12 carbon atoms, N-alkylsulfamoyl group having 1 to 6 carbon atoms, N, N having 2 to 12 carbon atoms -Dialkylsulfamoyl group and the like. Among them, halogen atom, alkyl group having 1 to 2 carbon atoms, cyano group, nitro group, alkylsulfonyl group having 1 to 2 carbon atoms, fluoroalkyl group having 1 to 2 carbon atoms, alkoxy group having 1 to 2 carbon atoms, carbon number Preferred are an alkylthio group having 1 to 2 carbon atoms, an N-alkylamino group having 1 to 2 carbon atoms, an N, N-dialkylamino group having 2 to 4 carbon atoms, and an alkylsulfamoyl group having 1 to 2 carbon atoms.

Halogen atom, alkyl group having 1 to 6 carbon atoms, cyano group, nitro group, alkylsulfinyl group having 1 to 6 carbon atoms, alkylsulfonyl group having 1 to 6 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 6 carbon atoms An alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, an N-alkylamino group having 1 to 6 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, and having 1 to 6 carbon atoms Examples of the N-alkylsulfamoyl group and the N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms are the same as those described above.

It is preferable that Y ¹ , Y ² and Y ³ are each independently any of the groups represented by the formulas (Y-1) to (Y-6).

[In the formulas (Y-1) to (Y-6), Z ² represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 6 carbon atoms, An alkylsulfonyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a thioalkyl group having 1 to 6 carbon atoms, an N-alkylamino group having 1 to 6 carbon atoms Represents an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 6 carbon atoms, or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.
a ¹ is an integer of 0 to 5, a ² is an integer of 0 to 4, b ¹ is an integer of 0 to 3, b ² is an integer of 0 to 2, R is a hydrogen atom or a methyl group. . ]

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

Furthermore, Y ¹ , Y ² and Y ³ each independently represent a group represented by the formula (Y-1) or the formula (Y-3) in view of the production process and the cost of the compound (1). Particularly preferred.

Preferably, W ¹ and W ² are each independently 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 the formula (1), Ar is preferably a group represented by the formula (Ar-6), and particularly, a group represented by the formula (Ar-6a), the formula (Ar-6b), the formula (Ar-6c), or the formula (Ar-10a) Or, a divalent group represented by (Ar-10b) is more preferable.

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

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

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

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

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

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

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

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

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

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

D ¹ and D ² are * -O-CO-, * -OC (= S)-, * -O-CR ¹ R ^2- , * -NR ¹ -CR ² R ³ -or * -NR ¹ -CO-(* represents a binding site to Ar.
) Is preferable. More preferably, D ¹ and D ² are * -O-CO-, * -OC (= S)-or * -NR ¹ -CO- (* represents a bonding site with 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, and more preferably a hydrogen atom, a methyl group or an ethyl group.

Examples of G ¹ and G ² include alicyclic hydrocarbon groups which may contain a hetero atom represented by the formulas (g-1) to (g-10), and include a 5- or 6-membered alicyclic ring. It is preferably a formula hydrocarbon group.

Groups represented by the above formulas (g-1) to (g-10) include alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, isopropyl group and tert-butyl group; methoxy group and ethoxy group and the like. An alkoxy group having 1 to 4 carbon atoms; a fluoroalkyl group having 1 to 4 carbon atoms such as a trifluoromethyl group; a fluoroalkoxy group having 1 to 4 carbon atoms such as a trifluoromethoxy group; a cyano group; It may be substituted by a halogen atom such as a chlorine atom and a bromine atom.

G ¹ and G ² are preferably an alicyclic hydrocarbon group having a 6-membered ring represented by the formula (g-1), more preferably a 1,4-cyclohexylene group, and trans Particularly preferred is a -1,4-cyclohexylene group.

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

As A ¹ and A ² , a part of the hydrogen atoms of the above-mentioned groups is an alkyl group having about 1 to 4 carbon atoms such as a methyl group, an ethyl group, an i-propyl group or a t-butyl group; A C1-C4 alkoxy group such as a methoxy group or an ethoxy group; a trifluoromethyl group; a trifluoromethyloxy group; a cyano group; a nitro group; which is substituted by a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom; Is also good.

A ¹ and A ² are particularly preferably the same type of group, since the production of the compound (1) is easy. A ¹ and A ² are each preferably a monocyclic 1,4-phenylene group or 1,4-cyclohexylene group, and particularly preferably a 1,4-phenylene group because of easy production of the compound (1). Is preferred.

It is preferable that B ¹ and B ² are the same type of divalent group because the production of the compound (1) is easy. Further the compound (1) produced is easier in, ^{B 1} and of ^{B 2,} ^{B 1} and ^{B 2} are attached only ^{A 1} and ^{A 2} are each _{independently,} -CH 2 -CH ₂ —, —CO—O—, —O—CO—, —CO—NH—, —NH—CO—, —O—CH ₂ —, —CH ₂ —O—, or a single bond is particularly preferable. -CO-O- or -O-CO- is preferable because of exhibiting liquid crystallinity. Of B ¹ and ^{B 2,} ^{B 1} and ^{B 2} is bound to ^{E 1} or ^{E 2} are each independently, -O -, - CO-O -, - O-CO -, - O-CO- More preferably, it is O-, -CO-NH-, -NH-CO- or a single bond.

From the viewpoint of liquid crystallinity, k and l each preferably independently represent an integer of 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 (provided that at least one of P ¹ and P ² represents a polymerizable group). It is preferable that both P ¹ and P ² are polymerizable groups, since the resulting retardation film tends to have excellent film hardness.
The polymerizable group is a substituent capable of polymerizing the compound (1) of the present invention, and specifically includes a vinyl group, a p-stilbene group, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group. Groups, carboxyl group, methylcarbonyl group, hydroxyl group, amide group, alkylamino group having 1 to 4 carbon atoms, amino group, epoxy group, oxetanyl group, aldehyde group, isocyanate group or thioisocyanate group. Further, the polymerizable group may include groups represented by B ¹ and B ² in order to bond the group exemplified above with E ¹ and E ² . For example, a radical polymerizable group or a cationic polymerizable group suitable for photopolymerization is preferable, and an acryloyl group or a methacryloyl group is preferable, and an acryloyl group is more preferable because handling is easy and production is easy. It is more preferable that both P ¹ and P ² are polymerizable groups, since the resulting retardation film tends to have excellent film hardness.

-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 ) ₁ -F ² -P ² Examples include groups represented by formulas (R-1) to (R-134). * (Asterisk) indicates the bonding position with Ar. In the formulas (R-1) to (R-134), n represents an integer of 2 to 12.

Further, the compound (1) includes compounds (i) to (xxxiv). R1 in the table represents -D ¹ -G ¹ -E ^1- (A ¹ -B ¹ ) _k -F ¹ -P ¹ , and R2 represents -D ² -G ² -E ^2- (A ² -B ²⁾ represents the _l -F ^² -P ^2.

In the compound (xxx) and the compound (xxxi), one of R1 and R2 is any of (R-57) to (R-120).
In Table 1, the compound (xvii) is a compound in which the group represented by Ar is a group represented by the formula (ar-78), and a compound in which the group represented by Ar is a group represented by the formula (ar-79) Alternatively, it means that the group represented by Ar is a mixture of a compound represented by the formula (ar-78) and a compound represented by the formula (ar-79).
In Table 2, compound (xxx) is a compound in which the group represented by Ar is a group represented by the formula (ar-120) and a compound in which the group represented by Ar is a group represented by the formula (ar-121) Or the compound represented by Ar is a mixture of a compound represented by the formula (ar-120) and a compound represented by the formula (ar-121), and the compound (xxxi) ) Is a compound wherein the group represented by Ar is a group represented by the formula (ar-122), a compound wherein the group represented by Ar is a group represented by the formula (ar-123), or the group represented by Ar is a compound represented by the formula It means any one of a mixture of the compound represented by the formula (ar-122) and the compound represented by the formula (ar-123).

Further, typical structural formulas of the compounds shown in Table 1 are exemplified below. In forming the retardation film, a plurality of different types of compounds (1) may be used.

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

Compound (1) can be synthesized by a known organic synthesis reaction (for example, condensation reaction, esterification reaction, Williamson reaction, etc.) described in Methoden der Organischen Chemie, Organic Reactions, Organic Syntheses, Comprehensive Organic Synthesis, New Laboratory Chemistry Course, etc. Ullmann reaction, Wittig reaction, Schiff base formation reaction, benzylation reaction, Sonogashira reaction, Suzuki-Miyaura reaction, Negishi reaction, Kumada reaction, Hiyama reaction, Buchwald-Hartwig reaction, Friedel Craft reaction, Heck reaction, Aldol reaction, etc. ) Can be produced by appropriately combining them according to the structure.

For example, in the case of the compound (1) in which D ¹ and D ² are * —O—CO—, the compound represented by the formula (1-1)

(In the formula, Ar represents the same meaning as described above.)
And a compound represented by the formula (1-2)

(Wherein G ¹ , E ¹ , A ¹ , B ¹ , F ¹ , P ¹ and k have the same meanings as described above) to give a compound of the formula (1-3)

(In the formula, Ar, G ¹ , E ¹ , A ¹ , B ¹ , F ¹ , P ¹ and k represent the same meaning as described above.)
And a compound represented by the formula (1-3) and a compound represented by the formula (1-4)

(Wherein, G ² , E ² , A ² , B ² , F ² , P ² and 1 have the same meanings as described above).
The reaction between the compound represented by the formula (1-1) and the compound represented by the formula (1-2) and the reaction between the compound represented by the formula (1-3) and the compound represented by the formula (1-4) The reaction is preferably performed in the presence of an esterifying agent.

As the esterifying agent (condensing agent), dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide, 1-ethyl-3- (3-dimethyl) are used in view of reactivity, cost, and usable solvent. Aminopropyl) carbodiimide ジ hydrochloride, bis (2,6-diisopropylphenyl) carbodiimide, bis (trimethylsilyl) carbodiimide, bisisopropylcarbodiimide, and 2,2′-carbonylbis-1H-imidazole are preferred.

(4) The composition containing a polymerizable liquid crystal may contain another liquid crystal compound (but different from the compound (1)) in addition to the compound represented by the formula (1).

Other liquid crystal compounds also preferably have a polymerizable group. Specific examples of other liquid crystal compounds include Chapter 3 of Liquid Crystal Handbook (Edited by Liquid Crystal Handbook Editing Committee, published by Maruzen Co., Ltd. on October 30, 2000). Molecular Structure and Liquid Crystallinity 3.2 Non-chiral rod-shaped liquid crystal molecules And 3.3 compounds having a polymerizable group among the compounds described in the chiral rod-shaped liquid crystal molecule.
As other liquid crystal compounds, a plurality of different compounds may be used in combination.

As other liquid crystal compounds, for example, compounds represented by the formula (4) (hereinafter sometimes referred to as “compound (4)”) and the like can be mentioned.

^{^{^{^{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, and is included in the aromatic hydrocarbon group, the alicyclic hydrocarbon group and the heterocyclic group. The hydrogen atom may be substituted by a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylamino group having 1 to 6 carbon atoms, a nitro group, a nitrile group or a mercapto group. .
B ¹¹ and ^{B 12} are each ^{^{independently, -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 a 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, and even when R ¹⁴ and R ¹⁵ are linked to form an alkylene group having 4 to 7 carbon atoms. Good.
E ¹¹ represents an alkylene group having 1 to 12 carbon atoms. A hydrogen atom contained in the alkylene group may be substituted with 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 having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a fluoroalkyl group having 1 to 13 carbon atoms, an alkylamino group having 1 to 13 carbon atoms, a nitrile group, Represents a polymerizable group which is a nitro group or is bonded via an alkylene group having 1 to 12 carbon atoms, and a hydrogen atom contained in the alkylene group is an alkyl group having 1 to 6 carbon atoms, It may be substituted by an alkoxy group or a halogen atom.
t represents an integer of 1 to 5. ]

In particular, the polymerizable group in P ¹¹ and G may be any group capable of polymerizing with the compound (1), and may be a vinyl group, a vinyloxy group, a p-stilbene group, an acryloyl group, an acryloyloxy group, a methacryloyl group, Methacryloyloxy group, carboxyl group, acetyl group, hydroxyl group, carbamoyl group, amino group, alkylamino group having 1 to 4 carbon atoms, epoxy group, oxetanyl group, formyl group, -N = C = O or N = C = S And the like. Among them, a radical polymerizable group or a cationic polymerizable group is preferable in that it is suitable for photopolymerization, and an acryloyloxy group, a methacryloyloxy group, or a vinyloxy group is preferable in terms of easy handling and easy production of a liquid crystal compound. Groups are preferred.

The aromatic hydrocarbon group, alicyclic hydrocarbon group, and heterocyclic group represented by A ¹¹ each have, for example, 3 to 18, preferably 5 to 12, and preferably 5 or 6 carbon atoms. Is particularly preferred.

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 the formulas (4-1) and (4-2), P ¹¹ , E ¹¹ , B ¹¹ , A ¹¹ , and B ¹² have the same meanings as described above.
F ¹¹ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a fluoroalkyl group having 1 to 13 carbon atoms, an alkylamino group having 1 to 13 carbon atoms, a cyano group. Represents a nitro group.
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 meanings as t. ]

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

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 the formulas (I) to (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 ].

In the compounds represented by the formulas (4-1), (4-2), (I), (II), (III), (IV) and (V), P ¹¹ and by appropriately selecting the combination of E ^11, by further appropriately selecting the combination of P ¹² and E ^12, it is preferable that they are bonded through an ether bond or an ester bond.

Specific examples of the compound (4) include, for example, the following formulas (I-1) to (I-5), formulas (II-1) to (II-6), and formulas (III-1) to (III) III-19), compounds represented by formulas (IV-1) to (IV-14), and formulas (V-1) to (V-5). Here, k represents an integer of 1 to 11. These liquid crystal compounds are preferred because they are easily synthesized and are easily available, such as being commercially available.

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

組成 The composition containing a 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 and sulfonium salts, and more specifically, Irgacure 907. Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369 (all manufactured by Ciba Specialty Chemicals), Seikeall BZ, Sequel Z, Sequel BEE (all manufactured by Seiko Chemical Co., Ltd.), Kayacure (kayacure) BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), Adeka Optomer SP-152 or Adeka Optomer SP-170 (all of which are manufactured by ADEKA Corporation) and the like.

The amount of the polymerization initiator to be used is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. When the amount of the polymerization initiator is within the above range, the compound (1) can be polymerized without disturbing the orientation.

波長 The wavelength dispersion characteristics of the retardation film can be arbitrarily determined by the content of the structural unit derived from the compound (1). When the content of the structural unit derived from the compound (1) among the structural units in the retardation film is increased, flatter wavelength dispersion characteristics, and further, inverse wavelength dispersion characteristics satisfying the formulas (α) and (β) Is shown.

波長 The wavelength dispersion characteristics of the retardation film can be confirmed by appropriate preliminary experiments. Hereinafter, a preliminary experiment in the case of using the compound (1) which is a preferable polymerizable liquid crystal will be described. About 2 to 5 types of liquid crystal compositions having different contents of the structural unit derived from the compound (1) are prepared, and a retardation film having the same thickness is produced for each liquid crystal composition as described later. The retardation value of the retardation film is determined, and from the result, the correlation between the content of the structural unit derived from the compound (1) and the retardation value of the retardation film is determined. What is necessary is just to determine the content of the structural unit derived from the compound (1) necessary to give a desired retardation value to the retardation film in a thickness.

膜厚 The thickness of the retardation film can be set so as to function most appropriately as a 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 producing retardation film functioning as λ / 4 plate)
The method for producing the retardation film will be described below. First, a liquid crystal composition is prepared by adding an organic solvent, other liquid crystal compounds, additives such as a polymerization initiator, a polymerization inhibitor, a photosensitizer, or a leveling agent to the compound (1) as necessary. . In particular, the liquid crystal composition is preferably in a liquid form, since film formation is easy. Further, the liquid crystal composition preferably contains an organic solvent, and has a function of curing the obtained retardation film. Therefore, the liquid crystal composition preferably contains a polymerization initiator.

The amount of the polymerization initiator to be used is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. Within the above range, the polymerizable liquid crystal can be polymerized without disturbing the orientation of the polymerizable liquid crystal.

(Polymerization inhibitor)
The liquid crystal composition can include a polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinones having a substituent such as hydroquinone or an alkyl ether, catechols having a substituent such as an alkyl ether such as butyl catechol, pyrogallols, 2,2,6,6-tetramethyl-1. Radical scavengers such as -piperidinyloxy radicals, thiophenols, β-naphthylamines and β-naphthols.

重合 By using the polymerization inhibitor, the polymerization of the polymerizable liquid crystal can be controlled, and the stability of the obtained retardation film can be improved. The amount of the polymerization inhibitor to be used is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. Within this range, the polymerizable liquid crystal can be polymerized without disturbing the orientation of the liquid crystal compound. In the case where other liquid crystal compounds are used as the polymerizable liquid crystal in addition to the compound (1), the standard of the preferable use amount of the polymerization inhibitor is the same as described above.

(Photosensitizer)
The liquid crystal composition can include a photosensitizer. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone, anthracenes having a substituent such as anthracene or an alkyl ether, phenothiazine and rubrene.

重合 By using a photosensitizer, the polymerization of the polymerizable liquid crystal can be increased in sensitivity. The amount of the photosensitizer used is, for example, 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. Within the above range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal. When other liquid crystal compounds are used as the polymerizable liquid crystal in addition to the compound (1), the standard of the preferable amount of the photosensitizer is the same as described above.

(Leveling agent)
The liquid crystal composition can include a leveling agent. Examples of the leveling agent include additives for radiation-curable paints (BYK-352, BYK-353, BYK-361N manufactured by BYK Japan), paint additives (SH28PA, DC11PA, ST80PA manufactured by Dow Corning Toray), Paint additives (KP321, KP323, X22-161A, KF6001 manufactured by Shin-Etsu Chemical Co., Ltd.) or fluorine-based additives (F-445, F-470, F-479 manufactured by Dainippon Ink and Chemicals, Inc.) Can be mentioned.

位相 By using a leveling agent, the retardation film can be smoothed. Further, in the production process of the optical film, the fluidity of the liquid crystal composition in a liquid state can be controlled, and the crosslink density of the obtained retardation film can be adjusted. The amount of the leveling agent used is 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal. Within this range, the polymerizable liquid crystal can be polymerized without disturbing the orientation of the polymerizable liquid crystal.

〔Organic solvent〕
As described above, the liquid crystal composition preferably contains an organic solvent. As the organic solvent used for preparing the liquid crystal composition, an organic solvent that can dissolve the polymerizable liquid crystal is preferable. Further, any solvent may be used as long as it is an inert solvent for the polymerization reaction, and specifically, alcohols such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve or butyl cellosolve; ethyl acetate, butyl acetate, ethylene glycol methyl ether Ester solvents such as acetate, gamma-butyrolactone or propylene glycol methyl ether acetate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone or methyl isobutyl ketone; aliphatic hydrocarbons such as pentane, hexane or heptane Solvent: aromatic hydrocarbon solvent such as toluene, xylene or chlorobenzene, acetonitrile, propylene glycol monomethyl ether, Rahidorofuran, dimethoxyethane, ethyl lactate, chloroform, phenol. These organic solvents may be used alone or in combination of two or more. In particular, the composition of the present embodiment has excellent compatibility and can be dissolved in alcohols, ester solvents, ketone solvents, non-chlorine aliphatic hydrocarbon solvents, non-chlorine aromatic hydrocarbon solvents, and the like. It can be dissolved and applied without using a halogenated hydrocarbon such as

(4) The viscosity of the liquid crystal composition is preferably adjusted to, for example, 10 Pa · s or less, preferably about 0.1 to 7 Pa · s, so as to facilitate application.

(4) The concentration of the solid content in the liquid crystal composition is, for example, 5 to 50% by weight. It is preferable that the concentration of the solid content is 5% or more, since the retardation film tends not to be too thin. Further, when the content is 50% or less, unevenness in the thickness of the retardation film tends to be less likely to occur.

Subsequently, the liquid crystal composition is applied to the support substrate, dried and polymerized to obtain a target retardation film on the support substrate. Hereinafter, the production of the retardation film will be described in detail.

[Unpolymerized film preparation process]
When the liquid crystal composition is applied on a supporting substrate and dried, an unpolymerized film is obtained. When the unpolymerized film exhibits a liquid crystal phase such as a nematic phase, the obtained retardation film has birefringence due to monodomain alignment. Since the unpolymerized film is oriented at a low temperature of about 0 to 120 ° C., and preferably at a low temperature of 25 to 80 ° C., a support base material which is not necessarily sufficient in terms of heat resistance as exemplified above can be used as the oriented film. Further, even after further cooling to about 30 to 10 ° C. after orientation, crystallization does not occur, so that handling is easy. The film thickness can be adjusted so as to give a desired phase difference by appropriately adjusting the application amount and the concentration of the composition.

(4) Examples of the method of applying the liquid crystal composition to the supporting substrate include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, and a die coating method. Further, a coating method using a coater such as a dip coater, a bar coater or a spin coater may be used.

支持 Examples of the support base include glass, plastic sheet, plastic film and translucent film. Examples of the translucent film include polyolefin films such as polyethylene, polypropylene, and norbornene polymers, polyvinyl alcohol films, polyethylene terephthalate films, polymethacrylate films, polyacrylate films, cellulose ester films, and polyethylene naphthalate films. , A polycarbonate film, a polysulfone film, a polyethersulfone film, a polyetherketone film, a polyphenylene sulfide film or a polyphenylene oxide film.

Even in a process requiring film strength, such as a lamination process, a transport process, and a storage process of a retardation film, the support substrate can be used to easily handle the film without breakage.

Further, it is preferable to form an alignment film on the supporting substrate and apply the liquid crystal composition on the alignment film. The alignment film has a solvent resistance that does not dissolve in the liquid crystal composition when the liquid crystal composition is applied, has heat resistance during solvent removal or heat treatment, and does not peel off due to friction or the like during rubbing. Is preferred. The alignment film can be formed from a composition containing a suitable polymer (a composition for forming an alignment film).

Examples of the polymer include polyamides and gelatins having an amide bond in the molecule, polyimides having an imide bond in the molecule, and polyamic acids which are hydrolysates thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, Examples include polymers such as polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylates. These polymers may be used alone, or two or more of them may be mixed or copolymerized. These polymers can be easily obtained by polycondensation by dehydration or deamination, chain polymerization such as radical polymerization, anionic polymerization, or cationic polymerization, coordination polymerization, or ring-opening polymerization.

Preferably, these polymers can be dissolved in a solvent and applied. An appropriate solvent can be selected depending on the solubility of the polymer used. Specific examples of the solvent include water, alcohols such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve or butyl cellosolve; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, gamma-butyrolactone or propylene glycol methyl ether. Ester solvents such as acetate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone or methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane or heptane; toluene, xylene or chlorobenzene Aromatic hydrocarbon solvent, acetonitrile, propylene glycol monomethyl ether, tetrahydrofuran, dimethoxy Ethane, ethyl lactate, chloroform and the like. These solvents may be used alone or in combination of two or more.

市販 To form the alignment film, a commercially available alignment film material may be used as it is. Examples of commercially available alignment film materials include Sanever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optmer (registered trademark, manufactured by JSR Corporation).

れば If such an alignment film is used, it is not necessary to control the refractive index by stretching, so that the in-plane variation of birefringence is reduced. Therefore, there is an effect that a phase difference film having a large area that can be used for a large-sized image display device can be provided.

As a method of forming an alignment film on the support substrate, for example, by coating on the support substrate a solution containing a commercially available alignment film material or a polymer to be a material of the alignment film, followed by annealing. An alignment film can be formed on the supporting substrate.

配向 The thickness of the alignment film thus obtained is, for example, 10 nm to 10000 nm, and preferably 10 nm to 1000 nm. Within the above range, the polymerizable liquid crystal can be aligned at a desired angle on the alignment film.

これら These alignment films can be subjected to a rubbing treatment as required. Thus, the polymerizable liquid crystal can be oriented in a desired direction.

As a method for rubbing the alignment film, for example, a method in which a rubbing cloth is wound and a rotating rubbing roll is placed on a stage and brought into contact with the alignment film being conveyed can be used.

As described above, in the unpolymerized film preparation step, an unpolymerized film (liquid crystal layer) is laminated on the alignment film laminated on the supporting substrate. Therefore, production of a film on a roll film is possible.

The drying of the solvent may be performed while the polymerization proceeds, but it is preferable to dry most of the solvent before the polymerization from the viewpoint of film forming properties.

Examples of the method for drying the solvent include methods such as natural drying, ventilation drying, and drying under reduced pressure. The specific heating temperature is preferably from 10 to 120 ° C, more preferably from 25 to 80 ° C. Further, the heating time is preferably from 10 seconds to 60 minutes, and more preferably from 30 seconds to 30 minutes. If the heating temperature and the heating time are within the above ranges, a support base material having insufficient heat resistance can be used as the support base material.

[Unpolymerized film polymerization process]
In the unpolymerized film polymerization step, the polymerizable liquid crystal contained in the unpolymerized film obtained in the unpolymerized film preparation step is polymerized and cured (hereinafter, polymerization of the polymerizable liquid crystal included in the unpolymerized film is referred to as “ Polymerization of unpolymerized film "). Thereby, a film in which the orientation of the polymerizable liquid crystal is fixed, that is, a polymerized film is obtained. Therefore, a polymer film having a small change in the refractive index in the plane direction of the film and a large change in the refractive index in the normal direction of the film can be produced.

The method of polymerizing the unpolymerized film is determined according to the type of the polymerizable liquid crystal used. As described above, when the compound (1), which is preferable as a polymerizable liquid crystal, is used, if the polymerizable group of P ¹ and / or P ² contained in the compound (1) is photopolymerizable, photopolymerization is performed. Is a thermopolymerizable polymer, the unpolymerized film can be polymerized by thermal polymerization. In the present invention, it is particularly preferable to polymerize the unpolymerized film by photopolymerization. According to the photopolymerization, the unpolymerized film can be polymerized at a low temperature, so that the heat resistance of the supporting substrate can be selected in a wide range. In addition, production becomes easy industrially. Photopolymerization is also preferable from the viewpoint of film formation. The photopolymerization is performed by irradiating the unpolymerized film with visible light or ultraviolet light. From the viewpoint of handleability, ultraviolet light is particularly preferred. The light irradiation may be performed while heating to a temperature at which the compound (1) takes a liquid crystal phase. At this time, the polymerized film can be patterned by masking or the like.

位相 Since the retardation film obtained by such a production method has good adhesion to the alignment film, the production of the retardation film is easy.

Furthermore, the retardation film obtained by using the polymerizable liquid crystal has an advantage that it is a thin film as compared with a stretched film which gives a phase difference by stretching.

において In the above-mentioned manufacturing method, a step of peeling off the supporting substrate may be included subsequent to the step. With such a configuration, the obtained film is a laminate including the support base material, the alignment film, and the retardation film. Further, in addition to the step of peeling the support base material, the method may further include a step of peeling the alignment film from the laminate. With such a configuration, a retardation film without an alignment film can be obtained.

The retardation film thus obtained has excellent transparency and is used as a film for various image display devices. As described above, the thickness of the formed retardation film differs depending on the retardation value of the obtained retardation film.

In the circularly polarizing plate of the present invention, the retardation film containing a liquid crystal material, which functions as a λ / 4 plate, contains foreign matter. The foreign material is a foreign material that can be inevitably mixed in the manufacturing process, for example, a foreign material generated by an alignment treatment of a liquid crystal compound, and more specifically, a foreign material (rubbing waste) generated by a rubbing process. When the retardation film is composed of a stretched film, such foreign matter is not present in the first place, and even if foreign matter is present, no display defect is caused due to the thickness of the stretched film. It is estimated to be. As described above, one of the features of the present invention is to prevent the adverse effect of a foreign substance that can cause a problem (display defect) when the retardation film is formed of a very thin liquid crystal material. Specifically, in one embodiment, the number of actual foreign substances in the retardation film made of a liquid crystal material is 100 / m ² or more, and may be, for example, about 150 / m ² to 300 / m ² . The average particle diameter of the foreign matter is typically 1.3 μm or less, and preferably 0.1 μm to 1.0 μm. In order to achieve such an average particle diameter range, a treatment for removing most of foreign substances having a particle diameter of 3 μm or more by, for example, blowing air onto the rubbed surface of the alignment film after the rubbing treatment. It is preferred to do so. On the other hand, in the circularly polarizing plate according to the embodiment of the present invention, the number of display defects is preferably 10 / m ² or less, and more preferably 8 / m ² or less. That is, according to the embodiment of the present invention, even when a large number of foreign substances exist in the retardation film, most of such foreign substances can be prevented from being recognized as display defects. The number of existing foreign substances can be recognized and measured by observing the circularly polarizing plate with, for example, an optical microscope (for example, a differential interference microscope). The number of display defects is recognized as a bright spot in a pseudo crossed Nicol state obtained by arranging a circularly polarizing plate in, for example, an optical microscope and arranging an inspection circularly polarizing plate using a retardation film composed of a stretched film. Can be measured.

The thickness of the retardation film functioning as a λ / 4 plate is 1.5 μm or more, and the surface is substantially flat. The upper limit of the thickness of the retardation film is not particularly limited, but can be 5 μm. With such a thickness, it is possible to make the surface substantially flat even if foreign matter is present. In this specification, “substantially flat” means that there is no protrusion having a height of 0.4 μm or more.

(4) The ratio of the thickness of the retardation film to the average particle diameter of the foreign matter is preferably 1.2 or more, more preferably 1.5 to 4.0. When the ratio is in such a range, the generation of projections due to foreign matter can be reduced, and a substantially flat surface can be favorably realized. As a result, display defects due to foreign matter can be favorably prevented.

(Second retardation film)
As the retardation film used in the present invention, a film obtained by laminating and integrating a second retardation film on the above retardation film can be used. In the case of using a laminate in which a plurality of types of retardation films such as the second retardation film are laminated, at least one of the plurality of types of retardation films constituting the laminate is used. Contains a liquid crystal material, satisfies the expressions (α) and (β), and has a film thickness of 1.5 μm or more. As the second retardation film, it is preferable to use a film produced without performing a treatment such as a rubbing treatment or a photo-alignment treatment. Such a retardation film can suppress the occurrence of alignment defects and the like, has almost no bright spot defects, and does not impair display quality. For example, as the second retardation film, a film having a refractive index characteristic showing a relationship of nz> nx ≧ ny is preferably used. By providing the second retardation film having such a refractive index characteristic, for example, when used as an anti-reflection polarizing plate, the angle dependence of the effect of absorbing reflected light is reduced, and the light is reflected at various angles. This is preferable because the emitted reflected light can be prevented from being emitted.

において In one embodiment, the second retardation film has a refractive index nx = ny. Here, “nx = ny” includes not only a case where nx and ny are exactly equal but also a case where nx and ny are substantially equal. Specifically, it means that Re (550) is less than 10 nm.

Ｒ Rth (550) of the second retardation film is preferably -260 nm to -10 nm, more preferably -230 nm to -15 nm, and still more preferably -215 nm to -20 nm. When the content is in such a range, the above-mentioned effect becomes remarkable, and thus it is preferable.

The second retardation film can be formed of any appropriate material, and is not particularly limited, but is preferably a liquid crystal layer fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method for forming the liquid crystal layer include, for example, the liquid crystal compounds and the formation methods described in JP-A-2002-333842, [0020] to [0042]. In this case, the thickness is preferably from 0.1 μm to 5 μm, more preferably from 0.2 μm to 3 μm.

位相 Re (550) at a wavelength of 550 nm of the retardation film on which the second retardation film is laminated is also 90 to 190 nm, preferably 110 to 170 nm, and more preferably 120 to 160 nm. When Re (550) of the second retardation film is within this range, even when the second retardation film is laminated with the first retardation film functioning as a λ / 4 plate, the laminated retardation film also functions as a λ / 4 plate. I do.

積層 To laminate and integrate the second retardation film, an arbitrary adhesive layer or pressure-sensitive adhesive layer can be used. The adhesive layer or the pressure-sensitive adhesive layer is made of, for example, an acrylic pressure-sensitive adhesive having a (meth) acrylic-based polymer as a base polymer or a rubber-based pressure-sensitive adhesive formed from a rubber-based resin. It exhibits adhesiveness, cohesiveness, and adhesive properties, and is excellent in weather resistance, heat resistance, and the like, and is therefore preferable. As the adhesive, various forms such as a water-based adhesive, a solvent-based adhesive, a hot-melt adhesive, and an active energy ray-curable adhesive are used, and a water-based adhesive or an active energy ray-curable adhesive is preferable. In addition, any known adhesive or pressure-sensitive adhesive layer can be used.

(Circularly polarizing plate)
Any appropriate adhesive (adhesive layer) or pressure-sensitive adhesive is used for laminating the layers constituting the circularly polarizing plate of the present invention. For lamination of the polarizing film and the retardation film, typically, an active energy ray (for example, ultraviolet ray) curable adhesive or pressure-sensitive adhesive layer is 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. The thickness of the pressure-sensitive adhesive layer is 1 to 30 μm, more preferably 3 to 20 μm, and further preferably 3 to 15 μm.

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

(Configuration of circular polarizing plate)
The configuration of the circularly polarizing plate of the present invention will be described in more detail.

For example, when a single-sided protective polarizing plate having a protective film on only one side of the polarizing film is used, a circular polarizing plate composed of a protective film / a polarizing film / an adhesive layer / a retardation film can be used. When a double-sided protective polarizing plate having a protective film on both sides of a polarizing film is used, a circularly polarizing plate composed of a protective film / a polarizing film / a protective film / an adhesive layer / a retardation film can be used. .

In the above structure, the angle between the absorption axis of the polarizing film and the slow axis of the retardation film is 35 ° to 55 °, more preferably 38 ° to 52 °, still more preferably 40 ° to 50 °, and 42 °. ° to 48 ° is more preferable, and 44 to 46 ° is particularly preferable.
When the angle is in such a range, a desired circular polarization function can be realized, which is preferable. In this specification, when an angle is referred to, unless otherwise specified, the angle includes angles in both clockwise and counterclockwise directions.

円 The circularly polarizing plate of the present invention may include an intervening layer such as an adhesive layer or a pressure-sensitive adhesive layer, an undercoat layer (primer layer), or an easy-adhesion layer other than those described above.

機能 Further, a functional layer can be provided on the circularly polarizing plate of the present invention. Provision of the functional layer is preferable because it is possible to suppress defects such as through cracks and nanoslits generated in the polarizing film. The functional layer can be formed from various forming materials. The functional layer can be formed, for example, by applying a resin material to the polarizing film.

Examples of the resin material for forming the functional layer include a polyester resin, a polyether resin, a polycarbonate resin, a polyurethane resin, a silicone resin, a polyamide resin, a polyimide resin, a PVA resin, and an acrylic resin. Can be mentioned. These resin materials can be used alone or in combination of two or more. Among them, one or more selected from the group consisting of polyurethane-based resins and polyvinyl alcohol (PVA) -based resins are preferable. PVA-based resins are more preferred. The form of the resin may be any of a water-based resin and a solvent-based resin. The form of the resin is preferably an aqueous resin, and more preferably a PVA resin. Further, as the aqueous resin, an acrylic resin aqueous solution or a urethane resin aqueous solution can be used.

The functional layer has a thickness of preferably 15 μm or less, more preferably 10 μm or less, still more preferably 8 μm or less, and still more preferably 6 μm or less, because the optical reliability and water resistance are reduced when the functional layer is too thick. Is more preferably 5 μm or less, particularly preferably 3 μm or less. On the other hand, the thickness of the functional layer is preferably at least 0.2 μm, more preferably at least 0.5 μm, even more preferably at least 0.7 μm. The functional layer having such a thickness is preferable because generation of cracks can be suppressed.

(Circular polarizing plate with adhesive)
The circularly polarizing plate of the present invention can be formed into a circularly polarizing plate with an adhesive by providing an adhesive layer on at least one surface. The pressure-sensitive adhesive layer can be provided on the side opposite to the polarizing film side with respect to the retardation film. The pressure-sensitive adhesive used is not particularly limited, and a known adhesive can be used.

粘着 As the pressure-sensitive adhesive layer, any material may be used as long as it is excellent in optical transparency and exhibits appropriate wettability, cohesiveness, and adhesive properties such as adhesiveness, but those having excellent durability and the like are preferably used. Specific examples of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer include a pressure-sensitive adhesive (also referred to as an acrylic pressure-sensitive adhesive or a rubber-based pressure-sensitive adhesive) made of an acrylic resin or a rubber-based resin.

The pressure-sensitive adhesive layer formed from the acrylic pressure-sensitive adhesive is not particularly limited, but includes butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and (meth) acrylic acid. (Meth) acrylate resins such as 2-ethylhexyl and copolymer resins using two or more of these (meth) acrylates are preferably used. In addition, a polar monomer is copolymerized in these resins. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, 2-N, N-dimethylaminoethyl (meth) Monomers having polar functional groups such as carboxyl groups, hydroxyl groups, amide groups, amino groups, and epoxy groups, such as acrylates and glycidyl (meth) acrylates, may be mentioned. In addition, a crosslinking agent is usually blended into the adhesive together with the acrylic resin.

In addition, various additives may be blended in the adhesive. Suitable additives include silane coupling agents and antistatic agents. The silane coupling agent is effective in increasing the adhesion to glass. Antistatic agents are effective in reducing or preventing the generation of static electricity.

厚み At least one of the adhesives preferably has a thickness of 3 to 50 μm. More preferably, it is 3 to 30 μm.

When the pressure-sensitive adhesive layer has conductivity, its resistance value may be appropriately selected, but is preferably, for example, in the range of 1 × 10 ⁹ to 1 × 10 ¹¹ Ω / □.

The method of forming the pressure-sensitive adhesive layer formed on the circularly polarizing plate can be performed by a known method.

(Laminate)
A laminate can be obtained by laminating a window or a touch sensor described later on the circularly polarizing plate of the present invention. The window may be made of glass, other than those described below. Examples of the laminate include a laminate including a circularly polarizing plate and a touch sensor, a laminate including a circularly polarizing plate and a window, or a laminate including a circularly polarizing plate, a touch sensor, and a window. In the laminate including the circularly polarizing plate, the touch sensor, and the window, the window, the touch sensor, and the circularly polarizing plate may be stacked in this order, or the window, the circularly polarizing plate, and the touch sensor may be stacked in this order. You may.

(Image display device)
An image display device according to the present invention includes the circularly polarizing plate or the laminate according to the present invention.
For example, a circularly polarizing plate can be laminated on the image display device via the pressure-sensitive adhesive layer.

公知 Any known image display device can be used. For example, the circularly polarizing plate of the present invention can be suitably used for an organic EL display device. In particular, it can be suitably used as an antireflection polarizing plate of a flexible organic EL display device.

(Flexible image display device)
The flexible image display device includes a laminate for a flexible image display device and an organic EL display panel, and the laminate for a flexible image display device is arranged on the viewing side with respect to the organic EL display panel, and is configured to be bendable. I have. The laminate for a flexible image display device may include a window, a circularly polarizing plate, and a touch sensor, and the order of lamination thereof is arbitrary, but a window, a circularly polarizing plate, a touch sensor or a window from the viewing side, It is preferable that the touch sensor and the circularly polarizing plate are stacked in this order. The presence of the circularly polarizing plate on the viewing side of the touch sensor is preferable because the pattern of the touch sensor is hardly viewed and the visibility of the displayed image is improved. Each member can be laminated using an adhesive, a pressure-sensitive adhesive or the like.
Further, a light-shielding pattern may be provided on any one of the window, the circularly polarizing plate, and the touch sensor.

(Window)
The window is disposed on the viewing side of the flexible image display device, and has a role of protecting other components from external impact or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer. However, a window in a flexible image display device is not rigid and rigid like glass, and has flexible characteristics. The window may be made of a flexible transparent substrate, and may include a hard coat layer on at least one surface.

透明 The transparent substrate used for the window has a visible light transmittance of 70% or more, preferably 80% or more. As the transparent substrate, any transparent polymer film can be used. Specifically, polyolefins such as polyethylene, polypropylene, polymethylpentene, norbornene or cycloolefin derivatives having a monomer unit containing cycloolefin, and (modified) cellulose such as diacetylcellulose, triacetylcellulose, and propionylcellulose , Acrylics such as methyl methacrylate (co) polymer, polystyrenes such as styrene (co) polymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, ethylene-vinyl acetate copolymer , Polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyesters such as polycarbonate and polyarylate, polyamides such as nylon Polyimides, polyamides imides, polyether imides, polyether sulfones, polysulfones, polyvinyl alcohols, polyvinyl acetals, polyurethanes, may be a film formed of a polymer such as epoxy resins. These polymers can be used alone or in combination of two or more. This polymer film may be an unstretched, uniaxial or biaxially stretched film. Preferably, among the transparent substrates described above, a polyamide film, a polyamideimide film or a polyimide film, a polyester film, an olefin film, an acrylic film, and a cellulose film excellent in transparency and heat resistance are preferable. It is also preferable to disperse inorganic particles such as silica, organic fine particles, and rubber particles in the polymer film. In addition, colorants such as pigments and dyes, fluorescent brighteners, dispersants, plasticizers, heat stabilizers, light stabilizers, infrared absorbers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. May be contained. The transparent substrate has a thickness of 5 to 200 μm, preferably 20 to 100 μm.

The window may be provided with a hard coat layer on at least one surface 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 such a range, there is an effect that sufficient abrasion resistance is ensured and excellent flex resistance. Further, curl generation due to curing shrinkage can be reduced.

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiating active energy rays or thermal energy. Above all, those based on active energy ray curing are preferable. An active energy ray is defined as an energy ray that can decompose a compound that generates an active species to generate an active species. Examples of the active energy ray include visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, γ-ray, and electron beam. Ultraviolet light is particularly preferred. The hard coat composition contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound.

The radical polymerizable compound is a compound having a radical polymerizable group. The radically polymerizable group contained in the radically polymerizable compound may be any functional group capable of causing a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond. Specific examples include a vinyl group and a (meth) acryloyl group. When the radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be the same or different. The number of radically polymerizable groups in one molecule of the radically polymerizable compound is preferably two or more from the viewpoint of improving the hardness of the hard coat layer. As the radical polymerizable compound, a compound having a (meth) acryloyl group is preferable, and a polyfunctional acrylate monomer having 2 to 6 (meth) acryloyl groups in one molecule is preferable. Oligomers having several (meth) acryloyl groups in the molecule called compounds or epoxy (meth) acrylates, urethane (meth) acrylates, and polyester (meth) acrylates are preferred. Can be used. It preferably contains at least one selected from epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate.

The cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, and a vinyl ether group. The number of the cationically polymerizable groups contained in one molecule of the cationically polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of improving the hardness of the hard coat layer. In addition, as the cationic polymerizable compound, a compound having at least one of an epoxy group and an oxetanyl group as a cationic polymerizable group is preferable. Cyclic ether groups such as an epoxy group and an oxetanyl group are preferable in that shrinkage due to the polymerization reaction is small. Among the cyclic ether groups, compounds having an epoxy group among compounds having various structures are easily available, do not adversely affect the durability of the obtained hard coat layer, and are easy to control the compatibility with the radical polymerizable compound. There is an advantage. The oxetanyl group among the cyclic ether groups is more likely to have a higher degree of polymerization than the epoxy group, is less toxic, hastens the rate of forming a network obtained from the cationically polymerizable compound in the obtained hard coat layer, Even in a region where the polymerizable compound is mixed, there is an advantage that an unreacted monomer is not left in the film and an independent network is formed.

Examples of the cationically polymerizable compound having an epoxy group include, for example, a polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, or a cyclohexene ring or a cyclopentene ring-containing compound, which is treated with a suitable oxidizing agent such as hydrogen peroxide or peracid. Alicyclic epoxy resin obtained by epoxidation; polyglycidyl ether of aliphatic polyhydric alcohol or its alkylene oxide adduct, polyglycidyl ester of aliphatic long-chain polybasic acid, homopolymer of glycidyl (meth) acrylate, Aliphatic epoxy resins such as copolymers; bisphenols such as bisphenol A, bisphenol F and hydrogenated bisphenol A, or glycidyl ethers produced by reacting derivatives thereof such as alkylene oxide adducts and caprolactone adducts with epichlorohydrin Ether, and novolac epoxy resins such as a and glycidyl ether type epoxy resins derived from bisphenols are exemplified.
The hard coat composition may further include a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cationic polymerization initiator, a radical and cationic polymerization initiator, and the like can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations, thereby promoting radical polymerization and cationic polymerization.

The radical polymerization initiator only needs to be capable of releasing a substance that initiates radical polymerization by at least one of irradiation with active energy rays and heating. For example, examples of the thermal radical polymerization initiator include organic peroxides such as hydrogen peroxide and perbenzoic acid, and azo compounds such as azobisbutyronitrile.

Examples of the active energy ray radical polymerization initiator include a Type 1 radical polymerization initiator in which radicals are generated by decomposition of a molecule and a Type 2 radical polymerization initiator in which a radical is generated by a hydrogen abstraction reaction in the presence of a tertiary amine. Yes, they can be used alone or in combination.

The cationic polymerization initiator may be any one that can release a substance that initiates cationic polymerization by at least one of irradiation with active energy rays and heating. As the cationic polymerization initiator, an aromatic iodonium salt, an aromatic sulfonium salt, a cyclopentadienyl iron (II) complex and the like can be used. These can initiate cationic polymerization by either or both of irradiation with active energy rays and heating depending on the difference in structure. The polymerization initiator may include 0.1 to 10% by weight based on 100% by weight of the entire hard coat composition. When the content of the polymerization initiator is less than 0.1% by weight, the curing cannot be sufficiently advanced, and it is difficult to realize the mechanical properties and adhesion of the finally obtained coating film. If the content exceeds 10% by weight, poor adhesion, cracking and curling due to curing shrinkage may occur.

The hard coat composition may further include at least one selected from the group consisting of a solvent and an additive. The solvent is capable of dissolving or dispersing the polymerizable compound and the polymerization initiator, and may be used without limitation as long as it is known as a solvent for a hard coat composition in the technical field. The additive may further include inorganic particles, a leveling agent, a stabilizer, a surfactant, an antistatic agent, a lubricant, an antifouling agent, and the like.

(Touch sensor)
The touch sensor is used as an input unit. Various types of touch sensors have been proposed, such as a resistive film type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, and a capacitance type, and any type may be used. Among them, the capacitance type is preferable. The capacitive touch sensor is divided into an active area and a non-active area located outside the active area. The active area is an area corresponding to an area (display unit) where a screen is displayed on the display panel, and is an area where a user's touch is sensed. Display area). The touch sensor has a flexible substrate; a sensing pattern formed on an active region of the substrate; a touch pattern formed on an inactive region of the substrate, and is connected to an external driving circuit through the sensing pattern and a pad unit. For each sensing line. The same material as the transparent substrate of the window can be used as the substrate having flexible characteristics. The substrate of the touch sensor preferably has a toughness of 2,000 MPa% or more from the viewpoint of suppressing cracks in the touch sensor. More preferably, the toughness may be from 2,000 MPa to 30,000 MPa%.

The sensing pattern may include a first pattern formed in a first direction and a second pattern formed in a 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, and must be electrically connected to each other in order to detect a touched point. The first pattern is a form in which each unit pattern is connected to each other via a joint, whereas the second pattern is a structure in which each unit pattern is separated from each other in an island form. A separate bridge electrode is required for connection. As the sensing pattern, a known transparent electrode material can be applied. For example, 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, and the like, and these can be used alone or in combination of two or more. Preferably, ITO can be used. 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 alone or in combination of two or more.

The bridge electrode may be formed on the insulating layer above the sensing pattern with an insulating layer interposed therebetween. The bridge electrode is formed on the substrate, and the insulating layer and the sensing pattern may be formed thereon. The bridge electrode may be formed of the same material as the sensing pattern, and may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more of these. You can also. Since the first and second patterns must be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joint 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 connect the second pattern through a contact hole formed in the insulating layer. The touch sensor has a difference in transmittance between a pattern region where a pattern is formed and, a non-pattern region where a pattern is not formed, specifically, a light transmittance induced by a difference in refractive index in these regions. As a means for appropriately compensating for the difference, an optical adjustment layer may be further included between the substrate and the electrode, and the optical adjustment layer may include an inorganic insulating material or an organic insulating material. The optical control layer can be formed by coating a photocurable composition containing a photocurable organic binder and a solvent on a substrate. The photocurable composition may further include inorganic particles. The refractive index of the optical control layer can be increased by the inorganic particles.

The photocurable organic binder may include, for example, a copolymer of monomers such as an acrylate monomer, a styrene monomer, and a carboxylic acid monomer. The photocurable organic binder may be a copolymer containing different repeating units such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit. The inorganic particles may include, for example, zirconia particles, titania particles, alumina particles, and the like. The photocurable composition may further include additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

層 Each layer (window, circularly polarizing plate, touch sensor) forming the laminate for a flexible image display device can be laminated with an adhesive. Adhesives include water-based adhesives, organic solvent-based adhesives, solvent-free adhesives, solid adhesives, solvent volatile adhesives, moisture-curable adhesives, heat-curable adhesives, anaerobic-curable adhesives, and active energy ray-curable adhesives. General-purpose adhesives such as adhesives, hardener-mixed adhesives, hot-melt adhesives, pressure-sensitive adhesives (adhesives), and rewetting adhesives can be used. Among them, water-based adhesives, active energy ray-curable adhesives, and pressure-sensitive adhesives are often used. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive strength and the like, and is 0.01 μm to 500 μm, preferably 0.1 μm to 300 μm. Although present, the thickness types may be the same or different.

(Shading pattern)
The light-shielding pattern can be applied as at least a part of a bezel or a housing of the flexible image display device. The visibility of the image is improved by concealing the wiring arranged on the peripheral portion of the flexible image display device by the light-shielding pattern so that the wiring is difficult to see. The 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 has various colors such as black, white, and metal. The light-shielding pattern can be formed of a pigment for realizing a color and a polymer such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, or silicone. These can be used alone or in a mixture of two or more. The light-shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light-shielding pattern may be 1 μm to 100 μm, preferably 2 μm to 50 μm. It is also preferable to provide a shape such as inclination in the thickness direction of the optical pattern.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, parts and percentages representing the content or the use amount are based on weight unless otherwise specified. In addition, the measurement of each physical property in the following examples was performed by the following method.

(1) Measurement of thickness:
The measurement was performed using a digital micrometer “MH-15M” manufactured by Nikon Corporation.

(2) Measurement of in-plane retardation and thickness direction retardation:
Using a phase difference meter “KOBRA (registered trademark) -WPR” made by Oji Scientific Instruments based on the parallel Nicol rotation method, in-plane retardation and thickness direction retardation at each wavelength at 23 ° C. It was measured.

(3) Number of Real Foreign Substances The circularly polarizing plates obtained in Examples and Comparative Examples were observed at a magnification of 50 using a differential interference microscope (OLYMPUS LG-PS2), and the number of recognized foreign substances was measured.

(4) Number of Display Defects The number of display defects was observed at a magnification of 100 times using a digital optical microscope (Digital Microscope VHX-500 manufactured by Keyence Corporation). Specifically, the circularly polarizing plates obtained in the examples and comparative examples were placed in a microscope, and observation was performed in a pseudo crossed Nicols state in which the circularly polarizing plates prepared in Production Example 5 described below were placed as inspection polarizing plates. went. The number of observed bright spots was defined as the number of display defects.

[Production Example 1] Production of polarizing film A 30 μm-thick polyvinyl alcohol film (average degree of polymerization: about 2400, degree of saponification of 99.9 mol% or more) was uniaxially stretched about 4 times by dry stretching, and the tension was further maintained. After immersion in pure water at 40 ° C. for 40 seconds, dyeing treatment was performed by immersing in an aqueous solution of iodine / potassium iodide / water having a weight ratio of 0.052 / 5.7 / 100 at 28 ° C. for 30 seconds. Was. Then, it was immersed in an aqueous solution of potassium iodide / boric acid / water having a weight ratio of 11.0 / 6.2 / 100 at 70 ° C. for 120 seconds. Successively, after washing with pure water at 8 ° C. for 15 seconds, while maintaining the tension at 300 N, the film was dried at 60 ° C. for 50 seconds and then at 75 ° C. for 20 seconds, and iodine was adsorbed and oriented on the polyvinyl alcohol film. A polarizing film having a thickness of 12 μm was obtained.

[Production Example 2] Production 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 a composition for forming an alignment film.
To a mixture of the following polymerizable liquid crystal compound A and polymerizable liquid crystal compound B at a mass ratio of 90:10, 1.0 part of a leveling agent (F-556; manufactured by DIC), and polymerization initiation 6 parts of an agent, 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one ("Irgacure 369 (Irg369)", manufactured by BASF Japan Ltd.) was added.
Further, 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 to obtain a liquid crystal composition.
Polymerizable liquid crystal compound A was produced by the method described in JP-A-2010-31223. The polymerizable liquid crystal compound B was produced according to the method described in JP-A-2009-173893. The respective molecular structures are shown below.
[Polymerizable liquid crystal compound A]

[Polymerizable liquid crystal compound B]

[Production of laminated body composed of support base material, alignment film, and alignment liquid crystal cured film]
After performing a corona treatment on a cycloolefin-based film (trade name “ZF-14-50” manufactured by Zeon Corporation) having a thickness of 50 μm as a supporting base material, a composition for forming an alignment film is applied using a bar coater. And dried at 60 ° C. for 1 minute and further at 80 ° C. for 3 minutes to form a film having a thickness of 89 nm.
Subsequently, a rubbing treatment was performed on the surface of the obtained film to form an alignment film. The rubbing treatment was performed using a semi-automatic rubbing device (trade name: LQ-008 type, manufactured by Joyo Engineering Co., Ltd.) and using a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Kako Co., Ltd.) with a pushing amount of 0.15 mm. The rotation was performed at 500 rpm and at a condition of 16.7 mm / s. Thereafter, compressed air was blown on the rubbed surface of the alignment film. The direction of the rubbing treatment was set to be 45 ° counterclockwise when viewed from the viewing side with respect to the direction of the absorption axis of the polarizing film when the rubbing treatment was performed.
Next, the liquid crystal composition is applied to the alignment film using a bar coater and dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp [trade name of Ushio Inc .: “Unicure VB-15201BY-A”] UV irradiation (integrated light quantity at a wavelength of 365 nm in a nitrogen atmosphere: 500 mJ / cm ² ) to form an alignment liquid crystal cured film and obtain a laminate comprising a substrate, an alignment film and a retardation film Was.

Re (λ) of the retardation film produced by the above method was obtained by laminating a cycloolefin-based film as a supporting base material after laminating to a glass via an adhesive (by peeling this cycloolefin-based film, The resulting film was referred to as “retardation film A”). When the thickness of the obtained retardation film A was measured with a laser microscope, the thickness was 2.1 μm. As a result of measuring the phase difference value Re (λ) at each wavelength, Re (450) = 121 nm, Re (550) = 142 nm, and Re (650) = 146 nm. Re (550) was in the range of 90 to 190 nm, and functioned as a λ / 4 plate. Re (450) / Re (550) = 0.85 and Re (650) / Re (550) = 1.03, which satisfied the relationship represented by the expressions (α) and (β). In addition, no protrusion having a height of 0.4 μm or more was found on the surface of the retardation film A, and it was confirmed that the film was substantially flat.

[Production Example 3] Production of retardation film B A 2% by mass aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000, completely saponified, manufactured by Wako Pure Chemical Industries, Ltd.) was used as a composition for forming an alignment film.

Next, 10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF, trade name Paliocolor LC242) and a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by Ciba Specialty Chemicals, trade name Irgacure (registered trademark) 907) 0.5 g of a benzotriazole-based ultraviolet absorber (containing 1%) was dissolved in 40 g of toluene to prepare a liquid crystal composition.

After performing a corona treatment on a cycloolefin-based film (trade name “ZF-14-50” manufactured by Zeon Corporation) having a thickness of 50 μm as a supporting base material, a composition for forming an alignment film is applied using a bar coater. And dried at 60 ° C. for 1 minute and further at 80 ° C. for 3 minutes to form a film having a thickness of 95 nm.
Subsequently, a rubbing treatment was performed on the surface of the obtained film to form an alignment film. The rubbing treatment was performed using a semi-automatic rubbing device (trade name: LQ-008 type, manufactured by Joyo Engineering Co., Ltd.) and using a cloth (trade name: YA-20-RW, manufactured by Yoshikawa Kako Co., Ltd.) with a pushing amount of 0.15 mm. The rotation was performed at 500 rpm and at a condition of 16.7 mm / s. The direction of the rubbing treatment was set to be 45 ° counterclockwise when viewed from the viewing side with respect to the direction of the absorption axis of the polarizing film when the rubbing treatment was performed.

Next, the liquid crystal composition was applied on the alignment film using a bar coater, and dried at 100 ° C. for 1 minute. Thereafter, a retardation film B was formed on the alignment film by irradiating ultraviolet rays (in a nitrogen atmosphere, integrated light quantity at a wavelength of 365 nm: 1200 mJ / cm ² ) using a high-pressure mercury lamp. When the thickness of the obtained retardation film B was measured with a laser microscope, the thickness was 973 nm. When the retardation value was measured, Re (550) = 135 nm, and the orientation angle was 75 ° with respect to the longitudinal direction of the TAC. Further, when the retardation values at the wavelengths of 450 nm and 650 nm were measured, Re (450) = 145 nm and Re (650) = 132 nm. Re (450) / Re (550) = 1.07 and Re (650) / Re (550) = 0.98, which did not satisfy the relationship of the formulas (α) and (β). Many projections having a height of 0.4 μm or more were observed on the surface of the retardation film B, and were not substantially flat.

[Production Example 4] Preparation of Second Retardation Film C A commercially available vertical alignment film (JALS-204R, manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied to the surface of a base film (triacetyl cellulose film, 80 μm thick) with methyl ethyl ketone. : 1 and then applied with a wire bar coater (application amount 2.4 ml / m ² ). Immediately, it was dried with 120 ° C. warm air for 120 seconds.

Next, 3.8 g of the following rod-shaped liquid crystal compound, 0.06 g of a photopolymerization initiator (Irgacure (registered trademark) 907), 0.02 g of a sensitizer (Kayacure (registered trademark) DETX, manufactured by Nippon Kayaku Co., Ltd.) A solution was prepared by dissolving 0.002 g of the following vertical alignment agent on the air interface side in 9.2 g of methyl ethyl ketone. This solution was applied to the alignment film side of the film on which the alignment film was formed with a wire bar, and heated at 100 ° C. for 2 minutes to align the rod-shaped liquid crystal compound. Next, the rod-shaped liquid crystal compound was cross-linked by UV irradiation at 80 ° C. with a 120 W / cm ² high-pressure mercury lamp for 20 seconds, and then allowed to cool to room temperature to produce a retardation layer having the characteristics of a positive C plate. The thickness of the obtained retardation layer was 0.5 μm, and 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.

[Production Example 5] Production of circular polarizing plate for inspection On one surface of the polarizing film obtained in Production Example 1, a polyvinyl alcohol-based adhesive was applied so that the thickness of the adhesive layer became 0.1 µm, and a protective film was formed. After laminating a (triacetyl cellulose (TAC) film (trade name: KC2UAW, thickness: 25 μm, manufactured by Konica Minolta Co., Ltd.), drying was performed at 80 ° C. for 2 minutes to produce a polarizing plate with a single-sided protective film.
A phase difference film (stretched film manufactured by Zeon Corporation; ZD12 series) is provided on the polarizing film side of the obtained polarizing plate with a single-sided protective film via an acrylic adhesive (NCF # L2, manufactured by Lintec Co., Ltd., thickness 5 μm). Re (550) = 141 nm). Here, lamination was performed such that the slow axis of the retardation film was 45 ° clockwise with respect to the absorption axis of the polarizing film.

[Example 1]
A protective film (triacetyl cellulose (TAC) film (trade name) was applied to one side of the polarizing film obtained in Production Example 1 while applying a polyvinyl alcohol-based adhesive so that the thickness of the adhesive layer was 0.1 μm. : KC2UAW, thickness: 25 µm, manufactured by Konica Minolta Co., Ltd.) and dried at 80 ° C for 2 minutes to prepare a polarizing plate with a single-sided protective film.
The retardation film A obtained in Production Example 2 was bonded to the polarizing film side of the obtained polarizing plate with a single-sided protective film via an acrylic pressure-sensitive adhesive (manufactured by Lintec Corporation, NCF # L2, thickness 5 μm). . Here, lamination was performed such that the slow axis of the retardation film A was 45 ° counterclockwise with respect to the absorption axis of the polarizing film. Further, after the base film of the retardation film A was peeled off, an acrylic pressure-sensitive adhesive (manufactured by Lintec Corporation, P-3132, thickness 25 μm) was attached to obtain a circularly polarizing plate. The obtained circularly polarizing plate had a structure of TAC film / adhesive layer / polarizing film / acrylic pressure-sensitive adhesive layer / retardation film A / acrylic pressure-sensitive adhesive / separator.

The obtained circularly polarizing plate was cut out to a size of 100 mm × 100 mm. The obtained circularly polarizing plate was subjected to the evaluations of (3) and (4). As a result of inspecting 100 of the obtained circularly polarizing plates, the number of existing foreign substances of the retardation film A was about 200 / m ² , and the number of display defects of the circularly polarizing plate was 7 / m ² . The foreign substance was polyvinyl alcohol and was rubbing waste.

[Example 2]
A protective film (triacetyl cellulose (TAC) film (trade name) was applied to both surfaces of the polarizing film obtained in Production Example 1 while applying a polyvinyl alcohol-based adhesive so that the thickness of the adhesive layer was 0.1 μm. : KC2CT, thickness: 20 µm, manufactured by Konica Minolta) and dried at 80 ° C for 2 minutes to prepare a polarizing plate with a double-sided protective film.
Evaluation samples were prepared in the same manner as in Example 1 except that the polarizing plate with a single-sided protective film was changed to the polarizing plate with a double-sided protective film. The obtained circularly polarizing plate had a structure of TAC film / adhesive layer / polarizing film / adhesive layer / TAC film / acrylic pressure-sensitive adhesive layer / retardation film A / acrylic pressure-sensitive adhesive / separator. .

The obtained circularly polarizing plate was cut out to a size of 100 mm × 100 mm. The obtained circularly polarizing plate was subjected to the evaluations of (3) and (4). As a result of inspecting 100 of the obtained circularly polarizing plates, the number of actual foreign substances of the retardation film was about 200 / m ² , and the number of display defects of the circularly polarizing plate was 6 / m ² . The foreign substance was polyvinyl alcohol and was rubbing waste.

[Example 3]
A protective film (triacetyl cellulose (TAC) film (trade name) was applied to one side of the polarizing film obtained in Production Example 1 while applying a polyvinyl alcohol-based adhesive so that the thickness of the adhesive layer was 0.1 μm. : KC2UAW, thickness: 25 µm, manufactured by Konica Minolta Co., Ltd.) and dried at 80 ° C for 2 minutes to prepare a polarizing plate with a single-sided protective film.
The retardation film A obtained in Production Example 2 was bonded to the polarizing film side of the obtained polarizing plate with a single-sided protective film via an acrylic pressure-sensitive adhesive (manufactured by Lintec Corporation, NCF # L2, thickness 5 μm). . Here, lamination was performed such that the slow axis of the retardation film A was 45 ° counterclockwise with respect to the absorption axis of the polarizing film. Further, after the base film of the retardation film A was peeled off, the retardation film C obtained in Production Example 4 was bonded via an acrylic pressure-sensitive adhesive (manufactured by Lintec Corporation, NCF # L2, thickness 5 μm). Finally, after peeling the base film of the retardation film C, an acrylic pressure-sensitive adhesive (manufactured by Lintec Corporation, P-3132, thickness 25 μm) was attached to obtain a circularly polarizing plate. The obtained circularly polarizing plate has a structure of TAC film / adhesive layer / polarizing film / adhesive layer / retardation film A / acrylic adhesive / retardation film C / acrylic adhesive / separator. Was.

[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 circularly polarizing plate was cut out to a size of 100 mm × 100 mm. The obtained circularly polarizing plate was subjected to the evaluations of (3) and (4). As a result of inspecting 100 obtained circularly polarizing plates, the number of actual foreign substances of the retardation film was about 200 / m ² , and the number of display defects of the circularly polarizing plate was 168 / m ² . The foreign substance was polyvinyl alcohol and was rubbing waste.

According to the present invention, a circularly polarizing plate which is extremely thin, has excellent anti-reflection properties, and has a reduced adverse effect on display performance of an image display device due to foreign matter can be obtained, which is useful.

Claims

A polarizing film and a retardation film functioning as a λ / 4 plate are provided in this order, and an angle between an absorption axis of the polarizing film and a slow axis of the retardation film is 35 ° to 55 °,
The retardation film includes a liquid crystal material,
The retardation film satisfies the following formulas (α) and (β);
Re (450) / Re (550) ≦ 1.00 (α)
1.00 ≦ Re (650) / Re (550) (β)
The retardation film contains foreign matter,
The thickness of the retardation film is 1.5 μm or more,
A circularly polarizing plate, wherein the surface of the retardation film is substantially flat.
[Wherein, Re (450) represents an in-plane retardation value at a wavelength of 450 nm, Re (550) represents an in-plane retardation value at a wavelength of 550 nm, and Re (650) represents an in-plane retardation value at a wavelength of 650 nm. Represent. ]
The circularly polarizing plate according to claim 1, wherein the foreign matter is rubbing waste.
A laminate comprising the circularly polarizing plate according to claim 1 and a touch sensor.
An image display device comprising the circularly polarizing plate according to claim 1.
An image display device comprising the laminate according to claim 3.
The image display device according to claim 4, wherein the image display device is an organic electroluminescence display device.