KR20190079451A - Liquid crystal retardation film, laminate comprising the same, polarizing plate comprising the same and light emitting display apparatus compsiring the same - Google Patents

Abstract

Provided are a liquid crystal retardation film having an absorbance ratio of 50% to 65% in equation 1, a laminate including the same, a polarizing plate including the same, and a luminescent display device including the same, wherein the equation 1 is absorbance ratio = Amax/A. × 100. Provided is a liquid crystal retardation film having excellent durability during UV irradiation.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal phase difference film, a laminate including the same, a polarizing plate including the same, and a light emitting display device including the same. BACKGROUND ART [0002] Liquid crystal retardation films,

The present invention relates to a liquid crystal phase difference film, a laminate including the same, a polarizing plate including the same, and a light emitting display including the same.

The organic light emitting display includes a polarizing plate including a polarizing film and a retardation layer, thereby making external light incident into the organic light emitting device linearly polarized and circularly polarized, thereby preventing incident light from being emitted to the outside, thereby improving visibility. In recent years, in order to make the polarizing plate thinner, the retardation layer is formed of a liquid crystal retardation film.

Generally, a liquid crystal retardation film can exhibit a retardation by forming an alignment film on a substrate and then supporting the liquid crystal and orienting the liquid crystal in accordance with the alignment direction of the alignment film. Recently, a liquid crystal phase difference film which is produced by aligning a liquid crystal by polarized UV without an alignment film has been developed. However, in the case of a liquid crystal retardation film oriented in one direction by polarized UV, when UV is incident from the outside in the process of using the liquid crystal, the remaining liquid crystal is not crosslinked and the retardation of the original liquid crystal retardation film is changed, There was a problem that it could fall. However, when the liquid crystal is excessively oriented in one direction, there is a problem that cracks are generated on the surface of the film in the liquid crystal alignment direction upon transfer from the substrate.

The background art of the present invention is described in Japanese Laid-Open Patent Publication No. 2014-032270.

An object of the present invention is to provide a liquid crystal phase difference film having excellent durability in UV irradiation.

Another object of the present invention is to provide a liquid crystal phase difference film in which cracking on the surface can be suppressed during transfer.

Another object of the present invention is to provide a liquid crystal phase difference film which is low in yellowness and can be used for a display device or the like.

It is still another object of the present invention to provide a laminate, a polarizing plate, and a light emitting display including the liquid crystal retardation film of the present invention.

The liquid crystal phase difference film of the present invention may have an absorbance ratio of 50% to 65% of the following formula 1:

<Formula 1>

Absorption ratio = A _max / A _I × 100

(In the above formula 1, A _I is the absorbance of the liquid crystal phase difference film at a wavelength of 263 nm,

A _max is the maximum absorbance of the liquid crystal phase difference film at a wavelength of 290 nm to 360 nm).

The laminate of the liquid crystal retardation film of the present invention may comprise the substrate and the liquid crystal retardation film of the present invention formed on at least one side of the substrate.

The polarizing plate of the present invention may include the liquid crystal retardation film of the present invention.

The light emitting display of the present invention may include the liquid crystal phase difference film of the present invention.

The present invention provides a liquid crystal phase difference film having excellent durability in UV irradiation.

The present invention provides a liquid crystal phase difference film in which cracking on the surface can be suppressed during transfer.

The present invention provides a liquid crystal phase difference film which is low in yellowness and can be used for a display device or the like.

The present invention provides a laminate, a polarizing plate, and a light emitting display including the liquid crystal retardation film of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a conceptual diagram for explaining the absorbance ratio of Equation 1 for the liquid crystal phase difference film of the present invention. Fig.

The present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In the present specification, "in-plane retardation (Re)" is represented by the following formula A, "thickness direction retardation (Rth)" is represented by the following formula B, "biaxiality degree (NZ)" is represented by the following formula These are all values measured at a wavelength of 550 nm:

<Formula A>

Re = (nx - ny) xd

<Formula B>

Rth = ((nx + ny) / 2 - nz) xd

<Formula C>

NZ = (nx - nz) / (nx - ny)

(Where nx, ny and nz are refractive indexes in the x-axis, y-axis and z-axis directions of the retardation layer at wavelengths of 550 nm and d is the thickness (unit: nm) of the retardation layer) .

The liquid crystal retardation film of the present invention is a non-alignment film liquid crystal retardation film having no alignment film, and may be composed of a crosslinked material of a photo alignment liquid crystal material. The photo-aligned liquid crystal material may include a photoreactive liquid crystal polymer having a photosensitive reactor.

The liquid crystalline polymer may have a unit composed of a mesogen-forming group and a photosensitive reactive group on the side chain (side chain) of the liquid crystalline polymer. By having the unit in the side chain, the liquid crystal polymer is oriented by the dimerization by linearly polarized UV irradiation, so that the retardation can be realized.

The mesogen-forming group is not particularly limited as long as it can impart liquid crystallinity to the liquid crystalline polymer. The mesogen-forming group may include a mesogen group as well as a hydrogen bonding mesogen which does not exhibit liquid crystallinity but exhibits liquid crystallinity by hydrogen bonding between molecules.

The mesogen group may be a group -Ar1-Y-Ar2- (wherein Ar1 and Ar2 each independently represent a substituted or unsubstituted arylene group having 6 to 20 carbon atoms or a substituted or unsubstituted heteroarylene group having 4 to 20 carbon atoms, Y is a single bond, an alkylene group having 1 to 3 carbon atoms, -CH = CH-, -C≡C-, -O-, -N = N-, -COO-, -OCO-, 6 to 10 arylene groups). The alignment positions of Ar1 and Ar2 are not particularly limited as long as they give liquid crystallinity. A para-configuration when Ar1 and Ar2 are phenylene groups, and a 2,6-configuration when Ar1 and Ar2 are naphthalene groups.

The photosensitive reactor is a functional group capable of being crosslinked by light energy, and examples thereof include a functional group capable of being crosslinked by a light energy such as a cinnamoyl group, a cinnamylidene group, a (meth) acryloyl group, a (meth) acryloyl group, a coumarin group, a benzophenone group, And the like. The (meth) acryloyl group-containing group may be a furyl (meth) acryloyl group, a biphenyl (meth) acryloyl group or a naphthyl (meth) acryloyl group. For example, the photosensitive reactor can be a cinnamoyl group, a coumarin group or a quinone group. The dimerization reaction may proceed in the photosensitive reactor when irradiated with a wavelength of 300 to 400 nm.

In this unit, the mesogen former and the photosensitive reactor may be directly bonded or may be bonded through a linking group. The linking group having a carbon number of 1 to 10 alkylene group, -O-, -S-, -SO-, -SO 2 -, -CH = CH-, -C≡C-, -N = N-, -COO-, -OCO- or an arylene group having 6 to 10 carbon atoms. The linking unit may be either alone or in combination with two or more of the units listed above.

In one embodiment, the unit can be represented by the following formula 1 or 2:

&Lt; Formula 1 >

(Wherein p is an integer of 1 to 12, q is an integer of 0 to 12, X is a single bond, an alkylene group having 1 to 10 carbon atoms, -O-, -S-, -SO-, -SO ₂ -, -CH = CH-, -C≡C-, -N = N-, -COO-, -OCO- or an arylene group having 6 to 10 carbon atoms, R ₁ and R ₂ each independently represent a hydrogen atom, An alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a halogen atom, W is a cinnamoyl group, a cinnamylidene group, a (meth) acryloyl group, a (Meth) acryloyl group-containing group, coumarin group, benzophenone group or quinone group). R ₁ in the same benzene group in the formula (1) may be the same or different. R ₂ in the same benzene group in Formula (1) may be the same or different.

(2)

(Wherein r is an integer of 0 to 12, s is 0 or 1, m is 0 or 1, n is an integer of 1 to 3, X is a single bond, an alkylene group having 1 to 10 carbon atoms, -O- _{, -S-, -SO-, -SO 2 -} , -CH = CH-, -C≡C-, -N = N-, -COO-, -OCO- , or an arylene group having 6 to 10, R ₅ , R ₆ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a halogen atom). In the formula (2), R ₅ in the same benzene group may be the same or different. In the formula (2), R ₆ in the same benzene group may be the same or different.

The liquid crystalline polymer may further include a unit which does not have a photosensitive reactor but has a mesogen-forming group. Specifically, the unit may be represented by the following Formula 3:

(3)

(Wherein p is an integer of 1 to 12, q is an integer of 0 to 12, Y is a single bond, an alkylene group having 1 to 10 carbon atoms, -O-, -S-, -SO-, -SO ₂ -, -CH = CH-, -C≡C-, -N = N-, -COO-, -OCO- or an arylene group having 6 to 10 carbon atoms, R ₃ and R ₄ each independently represent a hydrogen atom, An alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a halogen atom, T is a hydrogen atom, a hydroxyl group, An alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen, and a haloalkyl group having 1 to 10 carbon atoms). R ₃ may be the same or different in the same benzene group in the formula (3). In formula (3), R ₄ in the same benzene group may be the same or different.

In one embodiment, the liquid crystalline polymer may include a unit having a mesogen former and a photosensitive reactor in a side chain by polymerizing a monomer having a polymerizable group in the mesogen-forming group, the photosensitive reactor. The polymerizable group may be an acryloyl group, a methacryloyl group, an epoxy group, a vinyl ether group or the like.

The photo-aligned liquid crystal material may further comprise a liquid crystalline low molecule. The liquid crystalline low molecular weight has a weight average molecular weight lower than that of the liquid crystalline polymer and may have the above-mentioned mesogen former and photosensitive group. The mesogen-forming group and the photosensitive group may be bonded directly or via a linking group. In one embodiment, the liquid crystalline low molecular weight can be represented by the following formula:

&Lt; Formula 4 >

(In the formula 4, p, q are each independently 0 or 1, X is a single bond, an alkylene group, -O-, -S-, -SO-, -SO 2 C 1 -C 10 -, -CH = CH-, a -C≡C-, -N = N-, -COO-, -OCO- or a group having 6 to 10 carbon atoms in the arylene group, Z _1, Z ₂ is a single bond, having from 1 to 20 carbon atoms are each independently an alkylene group , An alkenylene group having 2 to 20 carbon atoms, R ₇ and R ₈ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, (Meth) acryloyl group, a coumarin group, a benzophenone group, a (meth) acryloyl group, a (meth) acryloyl group, a cinnamyl group, a cinnamylidene group, Rake is nongi). In formula (4), R ₁ and R ₂ in the same benzene group may be the same or different.

The inventors of the present invention have found out that in the liquid crystal phase difference film comprising the above-mentioned photo-orientable liquid crystal material, the ratio of the absorbance of the liquid crystal retardation film at a wavelength of 263 nm, which is the reference wavelength peak, to the maximum absorbance of the liquid crystal retardation film at a wavelength of 290 nm to 360 nm, 1 to 50% to 65%, the in-plane retardation change rate of the liquid crystal retardation film is low even when UV is irradiated to the liquid crystal retardation film, so that the liquid crystal retardation film is excellent in durability and reliability, It is possible to suppress the occurrence of cracks on the surface of the film, and the low yellowing degree can be used for a polarizing plate or a display device, thereby completing the present invention.

<Formula 1>

Absorption ratio = A _max / A _I × 100

(In the above formula 1, A _I is the absorbance of the liquid crystal phase difference film at a wavelength of 263 nm,

A _max is the maximum absorbance of the liquid crystal phase difference film at a wavelength of 290 nm to 360 nm).

Preferably, A _max can be measured at a wavelength of 314 nm.

Fig. 1 is a conceptual diagram for explaining the absorbance ratio of the formula 1 of the present invention. Fig. Absorbance A _I is measured at a wavelength of 263 nm with a wavelength of I. The absorbance is measured at a wavelength of 290 nm with wavelength II and a wavelength of 360 nm with wavelength III, and the maximum absorbance A _max is calculated. Then, the absorbance ratio can be calculated according to Equation (1).

In the formula (1), A _I represents the moiety of the liquid crystal which is not photo-reacted by the UV irradiation in the liquid crystal contained in the liquid crystal phase difference film. In one embodiment, the liquid crystal moiety may be -Ar1-Y-Ar2- group as described above.

In the above formula (1), A _max denotes the moiety of the liquid crystal which is photo-reacted by the UV irradiation in the liquid crystal contained in the liquid crystal phase difference film. In one embodiment, the moiety of the liquid crystal may be a cinnamoyl group, a coumarin group, or a quinone group, but is not limited thereto. Preferably, the absorbance ratio of the formula (1) may be 50% to 60%.

In one embodiment, the liquid crystal phase difference film may have an in-plane retardation (Re) of 80 nm to 130 nm at a wavelength of 550 nm, and a rate of change of in-plane retardation according to the following formula 2 may be 5% or less. The in-plane retardation of the liquid crystal retardation film is 90 to 120 nm, 100 to 120 nm, the in-plane retardation change rate is 2.5% or less, and 2% or less, for example, in the range of the in- Can be:

<Formula 2>

Plane retardation change ratio = Re (b) - Re (a) | / Re (a) x 100

(In the above formula 2, Re (a) represents the initial Re (unit: nm) of the liquid crystal retardation film at a wavelength of 550 nm,

Re (b) is Re (unit: nm) after UV irradiation of the liquid crystal retardation film at a wavelength of 550 nm.

Re (b) &amp;le; Re (a) in the above equation (2). Re (b) in the formula 2 may be 80 nm to 120 nm, for example, 90 nm to 120 nm, and 100 nm to 120 nm.

The "UV irradiation" may mean irradiating the liquid crystal retardation film with UV at a wavelength of 200 nm to 400 nm at an intensity of 0.68 W / m ² for 500 hours. "Re of the initial phase of the liquid crystal phase difference film" may mean Re of the liquid crystal phase difference film before UV irradiation.

In one embodiment, the liquid crystal phase difference film has an in-plane retardation of 80 nm to 130 nm at a wavelength of 550 nm, and when a liquid crystal retardation film is fixed on a substrate with an adhesive layer and then released, the number of cracks generated in the slow axis direction on the retardation film surface is 0 . The substrate may be a glass plate; Or a polyester resin such as polyethylene terephthalate, a cellulose resin such as triacetyl cellulose, a polycarbonate resin, or an acrylic resin film. The pressure-sensitive adhesive layer may comprise a conventional pressure sensitive adhesive (PSA) known to those skilled in the art, and may be formed of a pressure-sensitive adhesive composition including, for example, a (meth) acrylic copolymer and a curing agent.

In one embodiment, the liquid crystal phase difference film may have an in-plane retardation of 80 nm to 130 nm at a wavelength of 550 nm and a yellowness of 3 or less, for example, 2 or less. Within this range, it can be used in a display device.

Wherein the liquid crystal phase difference film comprises a step of applying a composition for liquid crystal phase shifting containing the photo-aligned liquid crystal material to a substrate to obtain a coating, a step of irradiating polarized UV to the coating, a step of heating the coating, Can be produced by a process of irradiating non-polarized UV. The liquid crystal phase difference film of the present invention can reach the absorbance ratio of the formula 1 by adjusting the irradiation dose of the polarized UV and the irradiation dose of the unpolarized UV in the step of irradiating the unpolarized UV in the step of irradiating the polarized UV.

The substrate is a glass plate; Or a polyester resin such as polyethylene terephthalate, a cellulose resin such as triacetyl cellulose, a polycarbonate resin, or an acrylic resin film.

The composition for liquid phase phase shifting may comprise a solvent. The composition may further comprise conventional additives. The solvent may include at least one of THF (tetrahydrofuran), DME (dimethoxyethane), EGM (ethylene glycol monomethyl ether), DMSO (dimethyl sulfoxide), and diethylene glycol dimethyl ether, Do not. The composition for liquid crystal phase shifting may be contained in an amount of 5 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the solvent.

The composition for liquid crystal phase shifting can be applied by a conventional method such as a spin coater, a slit coater, a spray coater, a roll coater or the like.

By irradiating the application of the photo-alignment liquid crystal material with the polarized UV, the photo-dimerization reaction of the liquid crystal aligned in the same direction as the direction of the electric field of the polarized light UV proceeds, whereby the main alignment direction of the liquid crystal can be determined. When irradiating polarized UV, there is no particular limitation, but a wire grid polarizer (WGP) can be used. The wavelength when irradiated with polarized UV light may be 200 nm to 500 nm, for example, 300 nm to 500 nm. The irradiation dose during the polarized UV irradiation may be 100 mJ / cm ² to 1,000 mJ / cm ² , for example, 100 mJ / cm ² to 500 mJ / cm ² . Within this range, the absorbance ratio of Equation (1) can be reached when irradiated with non-polarized UV described below.

The solvent remaining in the photo-aligned liquid crystal material can be volatilized by the step of heating the coating. In addition, the liquid crystalline low molecular weight can be oriented in accordance with the dimerization orientation direction formed by the photo-dimerization reaction of the liquid crystalline polymer by the polarized UV irradiation. The heating may be 60 deg. C to 200 deg. C, for example, 60 deg. C to 140 deg.

By the step of irradiating the non-polarized UV, the liquid crystalline polymer or the mixture of the liquid crystalline polymer and the liquid crystalline low molecule can be crosslinked in the non-alignment direction (arbitrary direction) different from the alignment direction. In the present invention, the degree of crosslinking of the liquid crystalline polymer crosslinked in the alignment direction and the degree of crosslinking of the crosslinked liquid crystalline polymer or the mixture of the liquid crystalline polymer and the liquid crystalline low molecule can be reached to the absorbance ratio of the formula (1).

Irradiation of non-polarized UV may be a wavelength of 190 nm to 500 nm, for example, 200 nm to 400 nm. By reaching the absorbance ratio of the formula 1 within the above range, the durability during UV irradiation is excellent and there is no cracking during transfer, and the yellowing degree of the liquid crystal retardation film is low and can be used in a display device. Irradiation of unpolarized UV can be performed on at least one of a metal halide lamp and a high-pressure mercury lamp, and a metal halide lamp may be preferable considering the irradiation wavelength distribution.

When irradiated with a dose of a non-polarized UV is 500mJ / cm ² to 3,000mJ / cm ^2, for example, be a 500mJ / cm ² to 2,500mJ / cm ^2. Within the above range, by reaching the absorbance ratio of the formula (1) of the present invention, durability upon UV irradiation can be excellent and cracking can be avoided during transfer, and the yellowing degree of the liquid crystal retardation film is low and can be used in a display device.

The liquid crystal phase difference film may be a retardation layer exhibiting a refractive index relationship of nx> nz> ny at a wavelength of 550 nm, wherein nx may be 1.5 to 1.65, ny may be 1.4 to 1.55, and nz may be 1.5 to 1.6. Within the above range, an optical compensation effect can be obtained on the display device.

The liquid crystal phase difference film may have a degree of biaxiality of 0.2 to 0.8, for example, 0.4 to 0.6 at a wavelength of 550 nm. In the above range, an excellent viewing angle effect may be obtained.

The liquid crystal phase difference film may have a Rth of -50 nm to 50 nm, for example, -20 nm to 20 nm and -10 nm to 10 nm at a wavelength of 550 nm. Within this range, there may be a viewing angle improvement and antireflection effect.

The liquid crystal retardation film may have a thickness of 2 탆 or less, for example, 0.5 탆 to 2 탆. Within the above range, the polarizing plate thinning effect can be achieved.

The laminate of the liquid crystal retardation film of the present invention may comprise the substrate and the liquid crystal retardation film of the present invention formed on at least one side of the substrate.

The number of cracks generated in the direction of the slow axis at the surface of the phase difference film during transfer by releasing the liquid crystal retardation film from the base material may be 0 in the laminated product of the liquid crystal phase difference film. In the above range, it can be used as a retardation film. Further, the liquid crystal phase difference film is excellent in durability and reliability by satisfying the absorbance ratio of the formula (1).

The substrate may include, but is not limited to, a glass plate, a polyester resin such as polyethylene terephthalate, a cellulose resin such as triacetyl cellulose, a polycarbonate resin, or an acrylic resin film. The liquid crystal phase difference film may be formed directly on the base material without the laminating layer, or may be formed on the liquid crystal phase difference film through the laminating layer.

The polarizing plate of the present invention may include the liquid crystal retardation film of the present invention.

In one embodiment, the polarizing plate includes a polarizing film, a first retardation film formed on one side of the polarizing film, and the first retardation film may include the liquid crystal retardation film of the present invention. Therefore, even if the polarizing film does not contain a UV absorber, the in-plane retardation change amount of the liquid crystal retardation film upon UV irradiation in the polarizing plate is low, so that durability and reliability can be excellent. The polarizing plate can be used as an antireflection polarizing plate in a light emitting display, but is not limited thereto.

The polarizing film may include a polyvinyl alcohol polarizer obtained by dyeing iodine or the like on a polyvinyl alcohol film or a polyene polarizer obtained by dehydration of a polyvinyl alcohol film. The polarizer may have a thickness of 5 占 퐉 to 50 占 퐉. And can be used for a display device in the above range.

The polarizing film may include the polarizer described above and a protective layer formed on at least one side of the polarizer. The protective layer may comprise one or more of an optically transparent, protective film or protective coating layer. The protective film may include a protective film formed of an optically transparent resin. The protective film may be formed by melting and extruding the resin. If necessary, a further stretching process may be added. The resin includes a cyclic polyolefin-based resin including a cellulose ester-based resin including triacetyl cellulose and the like, an amorphous cyclic olefin polymer (COP), a polycarbonate-based resin, polyethylene terephthalate Based resin, a polyacrylate-based resin including a polyamide-based resin, a polyimide-based resin, a non-cyclic-polyolefin-based resin, and a polymethylmethacrylate resin, A polyvinyl alcohol-based resin, a polyvinyl chloride-based resin, and a polyvinylidene chloride-based resin.

The protective coating layer may be formed of an active energy ray-curable resin composition comprising an active energy ray-curable compound and a polymerization initiator.

The thickness of the protective layer may be in the range of 5 탆 to 200 탆, specifically 30 탆 to 120 탆, 50 탆 to 100 탆 in the protective film type, and 5 탆 to 50 탆 in the protective coating layer type. And can be used for a display device in the above range. A functional coating layer, for example, a hard coating layer, a translucent layer, an antireflection layer, or the like may be further formed on one side or both sides of the protective layer.

In another embodiment, the polarizing plate of the present invention comprises a polarizing film, a sequentially formed first retardation film and a second retardation film formed on one side of the polarizing film, wherein one of the first retardation film and the second retardation film And may include the liquid crystal phase difference film of the present invention. The other of the first retardation film and the second retardation film may include a retardation film having an in-plane retardation different from that of the liquid crystal retardation film of the present invention.

In one embodiment, the second retardation film is the liquid crystal retardation film of the present invention, and the first retardation film has Re at 220 nm to 280 nm and preferably 230 nm to 280 nm at a wavelength of 550 nm. In the above range, the side reflectance can be lowered. The second phase difference film may include at least one of a liquid crystal phase difference film and a resin film, but is not limited thereto.

The light emitting display of the present invention may include the polarizing plate for the light emitting display of the present invention. The light emitting display may be an apparatus including a light emitting element. The light emitting device includes an organic or organic light emitting device and includes a light emitting diode such as a light emitting diode (OLED), an organic light emitting diode (OLED), a quantum dot light emitting diode (QLED) can do. For example, the light emitting display device may include an organic light emitting element display device.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Example  One

15 parts by weight of MHZC-100A (Hayashi telempu) containing a liquid crystal polymer as a photo-orientable material was dissolved in 100 parts by weight of a solvent THF (tetrahydrofuran) to prepare a liquid crystal retardation film composition.

The composition was applied to a polyethylene terephthalate film (thickness: 80 탆, manufactured by toyobo), which was a base film, and dried at 60 캜. Ultraviolet light from an LED lamp (600 W, wavelength 365 nm) was passed through a WGP (wire grid polarizer) to irradiate the dried coating material with linearly polarized UV at 300 mJ / cm ² . After irradiation, it was heated at 130 캜 and cooled. The obtained coating material was irradiated with a non-polarized UV at 700 mJ / cm ² with a metal halide lamp (6 KW, wavelength: 200 nm to 400 nm) to prepare a liquid crystal retardation film having a thickness of 2 탆.

Example  2

In Example 1, a liquid crystal retardation film was produced in the same manner, except that unpolarized UV was irradiated with a metal halide lamp at 1,400 mJ / cm ² .

Example  3

In Example 1, a liquid crystal retardation film was produced in the same manner, except that unpolarized UV was irradiated at 2,100 mJ / cm ² with a metal halide lamp.

Example  4

A liquid crystal retardation film was produced in the same manner as in Example 1 except that the linear polarized UV was irradiated at 500 mJ / cm ² .

Comparative Example  One

In Example 1, a liquid crystal retardation film was produced in the same manner, except that a non-polarized UV of 700 mJ / cm ² was not irradiated with a metal halide lamp.

Comparative Example  2

A liquid crystal retardation film was produced in the same manner as in Example 1, except that polarized UV was not irradiated and unpolarized UV was irradiated with a metal halide lamp at 700 mJ / cm ² .

Comparative Example  3

In Example 1, a liquid crystal retardation film was produced in the same manner, except that unpolarized UV was irradiated with a metal halide lamp at 3,500 mJ / cm ² .

The liquid crystal phase difference films prepared in Examples and Comparative Examples The following physical properties were evaluated, and the results are shown in Table 1 below.

Property evaluation

(1) Absorbance: The prepared liquid crystal retardation film was measured for absorbance at a wavelength of 263 nm and maximum absorbance at a wavelength of 290 to 360 nm using V-650 (Jasco). The absorbance ratio of the formula 1 was calculated using the absorbance measured.

(2) UV durability: Re was measured at a wavelength of 550 nm using Axoscan for the prepared liquid crystal retardation film and represented by Re (a). The liquid crystal retardation film was irradiated with a UV light having a wavelength of 200 nm to 400 nm under a Carbon-arc lamp for 500 hours in a liquid crystal retardation layer at an intensity of 0.68 W / m ² , Re was measured at a wavelength of 550 nm in the same manner as described above, Respectively. The in-plane retardation change ratio was calculated according to the formula 2 using the obtained Re at 550 nm.

(3) Cracking during transfer: After laminating the liquid crystal surface to the film coated with the adhesive layer, remove the polyethylene terephthalate and measure the number of cracks. "X" when no crack occurred, and "O" when only one crack occurred.

(4) Whether yellowing occurred: Whether yellowing occurred or not was evaluated for the produced liquid crystal retardation film. When the liquid crystal phase difference film was evaluated by naked eye, it was evaluated as "X" when yellowing did not occur and "O" when yellowing occurred.

Example Comparative Example One 2 3 4 One 2 3 The irradiation dose of polarized UV (mJ / cm ² ) 300 300 300 500 300 0 300 Dose of the non-polarized UV (mJ / cm ²⁾ 700 1400 2100 700 0 700 3500 Absorbance @ 263 nm 3.44 3.49 3.45 3.44 3.47 3.69 3.46 Maximum absorbance
@ 290 nm ~ 360 nm 2.05 1.98 1.9 2 2.33 3.21 1.68 Absorbance ratio (%) of formula (1) 59.6 56.7 55.1 58.1 67.1 87.0 48.6 Re (a) (nm) 115.6 110.8 105.6 115.0 130.0 0.8 87.6 Re (b) (nm) 114.4 109.8 105.0 113.7 115.0 - 85.0 The in-plane retardation change ratio (%) of the formula (2) 1.04 0.90 0.57 1.13 11.54 - 2.97 Crack occurrence X X X X O O X Yellowing X X X X X X O

As shown in Table 1, the liquid crystal retardation film of the present invention has excellent durability during UV irradiation, can suppress cracking on the surface at the time of transfer, has no yellowing and low yellowing, .

On the other hand, in Comparative Example 3 in which the absorbance ratio of Formula 1 is less than 50%, yellowing occurs and it can not be used in a display device. In Comparative Example 1 and Comparative Example 2 in which the absorbance ratio of Formula 1 was more than 65%, cracks occurred during transfer and the in-plane retardation change ratio of Formula 2 was high, so that durability and reliability were not good. Also, in Comparative Example 2 in which the absorbance ratio of Formula 1 was 87.0%, which was too high as compared with 65%, there was no target phase difference of the present invention before UV durability evaluation.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (13)

A liquid crystal phase difference film having an absorbance ratio of 50% to 65%
<Formula 1>
Absorption ratio = A _max / A _I × 100
(In the above formula 1, A _I is the absorbance of the liquid crystal phase difference film at a wavelength of 263 nm,
A _max is the maximum absorbance of the liquid crystal phase difference film at a wavelength of 290 nm to 360 nm).
The liquid crystal phase difference film according to claim 1, wherein the liquid crystal phase difference film is a non-alignment film liquid crystal phase difference film.
The liquid crystal phase difference film according to claim 1, wherein the liquid crystal phase difference film comprises a side chain crosslinkable liquid crystal.
The liquid crystal phase difference film according to claim 3, wherein the liquid crystal comprises a photo-alignment liquid crystal polymer.
The liquid crystal phase difference film according to claim 3, wherein the photoadynamic liquid crystal polymer comprises a unit represented by the following formula (1) or (2):
&Lt; Formula 1 >

(Wherein p is an integer of 1 to 12, q is an integer of 0 to 12, X is a single bond, an alkylene group having 1 to 10 carbon atoms, -O-, -S-, -SO-, -SO ₂ -, -CH = CH-, -C≡C-, -N = N-, -COO-, -OCO- or an arylene group having 6 to 10 carbon atoms, R ₁ and R ₂ each independently represent a hydrogen atom, An alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a halogen atom, W is a cinnamoyl group, a cinnamylidene group, a (meth) acryloyl group, a (Meth) acryloyl group-containing group, coumarin group, benzophenone group or quinone group),
(2)

(Wherein r is an integer of 0 to 12, s is 0 or 1, m is 0 or 1, n is an integer of 1 to 3, X is a single bond, an alkylene group having 1 to 10 carbon atoms, -O- _{, -S-, -SO-, -SO 2 -} , -CH = CH-, -C≡C-, -N = N-, -COO-, -OCO- , or an arylene group having 6 to 10, R ₅ , R ₆ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a halogen atom).
The liquid crystal phase difference film according to claim 1, wherein the liquid crystal phase difference film has an in-plane retardation of 80 nm to 130 nm at a wavelength of 550 nm.
The liquid crystal phase difference film according to claim 1, wherein the liquid crystal phase difference film has an in-plane retardation change ratio according to the following formula (2): 5%
<Formula 2>
Re (a) - Re (b) | / Re (a) 占 100
(In the above formula 2, Re (a) represents the initial Re (unit: nm) of the liquid crystal retardation film at a wavelength of 550 nm,
Re (b) is Re (unit: nm) after UV irradiation of the liquid crystal retardation film at a wavelength of 550 nm.
The liquid crystal phase difference film according to claim 1, wherein the liquid crystal phase difference film has a degree of biaxiality of 0.2 to 0.8 at a wavelength of 550 nm.
The liquid crystal phase difference film according to claim 1, wherein the liquid crystal retardation film has a yellowness degree of 3 or less.
materials; And a liquid crystal phase difference film according to any one of claims 1 to 9 formed on one surface of the substrate.
The liquid crystal phase difference film laminate according to claim 10, wherein the liquid crystal phase difference film laminate has zero cracks generated from the base material in the slow axis direction of the liquid crystal phase difference film at the time of transferring the liquid crystal phase difference film.
Polarizing film; And a liquid crystal retardation film according to any one of claims 1 to 9 formed on one surface of the polarizing film.
An optical display device comprising the polarizing plate of claim 12.

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