KR20210121022A - Optical film, polarizing plate, and image display device - Google Patents

Abstract

An optical film comprising a resin layer A, wherein the resin layer A is formed of a resin A, wherein the resin A contains 50 wt% or more of an alicyclic structure-containing polymer and a UV absorber, the optical film comprising: The light transmittance in a wavelength of 300 nm or more and 410 nm or less is 10% or less, the light transmittance in a wavelength of 430 nm is 80% or more, and the increase rate of the light transmittance in a wavelength of 410 nm or more and 420 nm or less is 4.0%/nm or more, optical film.

Description

Optical film, polarizing plate, and image display device

The present invention relates to an optical film, a polarizing plate, and an image display device.

An image display apparatus may be equipped with the circular polarizing plate for reducing reflection of external light. Since an image display apparatus can be used in environments, such as outdoors with a large ultraviolet-ray intensity, in order to protect a polarizer from an ultraviolet-ray, the optical film containing a ultraviolet absorber may be equipped in an image display apparatus (patent document 1).

Japanese Laid-Open Patent Publication No. 2017-187619

In order to reduce the influence on the color of a displayed image, the optical film with which the image display apparatus is equipped has considered that it is preferable that the light transmittance of the light of a visible region is high. For example, when the absorption loss of the light transmittance of light in the visible region is large, the absorption of light at a specific wavelength in the visible region becomes large, and a color image may be obtained when the screen is set to a white display state.

On the other hand, when a retardation film such as a λ/4 plate is used for the circular polarizing plate of the image display device, depending on the wavelength dispersion of the retardation Re in the in-plane direction of the retardation film, the image display device is observed from the front direction. The color of the case may deviate from the original color. For example, when the retardation Re in the in-plane direction of the retardation film is forward wavelength dispersion, light of a wavelength in the violet to blue region reflected by the reflective electrode of the image display device or the like passes through the polarizer and is visually recognized , when the screen is set to a black display state, the screen may appear blue in some cases. Here, that the retardation in the in-plane direction has forward wavelength dispersion means that the retardation Re (450) in the in-plane direction at a wavelength of 450 nm and the retardation Re (550) in the in-plane direction at a wavelength of 550 nm are the following means that the expression is satisfied.

Re(450)/Re(550) ≥ 1

Accordingly, an optical film capable of protecting the image display device from ultraviolet rays and improving color when the image display device is viewed from the front direction; a polarizing plate capable of protecting the image display device from ultraviolet rays and improving color when the image display device is viewed from the front direction; There is a demand for an image display device in which the color when viewed from the front direction is improved.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the present inventors earnestly examined. As a result, the light transmittance in a wavelength of 300 nm or more and 410 nm or less is 10% or less, the light transmittance in a wavelength of 430 nm is 80% or more, and the increase rate of the light transmittance in a wavelength of 410 nm or more and 420 nm or less is 4.0%/nm By the above optical film, it found out that the said subject was solved, and completed this invention.

That is, the present invention provides the following.

[1] An optical film comprising a resin layer A,

The resin layer A is formed of the resin A,

The resin A contains 50% by weight or more of an alicyclic structure-containing polymer and a UV absorber,

The optical film has a light transmittance of 10% or less at a wavelength of 300 nm or more and 410 nm or less, a light transmittance of 80% or more at a wavelength of 430 nm, and an increase rate of the light transmittance at a wavelength of 410 nm or more and 420 nm or less, 4.0% /nm or more,

optical film.

[2] Further comprising a resin layer B1 and a resin layer B2,

The resin layer B1 is formed on one surface of the resin layer A,

The resin layer B2 is formed on the other surface of the resin layer A,

The resin layer B1 is formed of a thermoplastic resin B1 having a UV absorber content of 3.0 wt% or less,

The optical film according to [1], wherein the resin layer B2 is formed of a thermoplastic resin B2 having an ultraviolet absorber content of 3.0 wt% or less.

[3] The optical film according to [2], which is a co-extrusion film.

[4] The optical film according to any one of [1] to [3], wherein the ultraviolet absorber contains a compound having a sesamol structure and a benzotriazole structure.

[5] The optical film according to any one of [1] to [4], wherein the retardation Re (590) in the in-plane direction at a wavelength of 590 nm is 0.1 nm or more.

[6] A polarizing plate comprising the optical film according to any one of [1] to [5] and a polarizer.

[7] The polarizing plate according to [6], further comprising a retardation layer C having an in-plane direction retardation Re (590) of 70 nm or more at a wavelength of 590 nm.

[8] An image display device comprising the polarizing plate according to [6] or [7].

The present disclosure also includes the following contents.

[9] The method for producing the optical film according to [3], comprising:

The thermoplastic resin B1, the resin A, and the thermoplastic resin B2 are co-extruded from a die to form an extruded film in which the layer of the thermoplastic resin B1, the layer of the resin A, and the layer of the thermoplastic resin B2 are laminated in this order. The manufacturing method of the optical film including the process of obtaining.

Advantageous Effects of Invention According to the present invention, an optical film capable of protecting an image display device from ultraviolet rays and improving the color when the image display device is observed from the front direction; a polarizing plate capable of protecting the image display device from ultraviolet rays and improving color when the image display device is viewed from the front direction; It is possible to provide an image display device in which the color when observed from the front direction is improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the optical film which concerns on 2nd Embodiment.
It is sectional drawing which shows typically the polarizing plate which concerns on 3rd Embodiment.
It is sectional drawing which shows typically the polarizing plate which concerns on 4th Embodiment.
4 is a cross-sectional view schematically showing an image display device according to a fifth embodiment.
5 is a cross-sectional view schematically showing an image display device according to a sixth embodiment.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, this invention is not limited to embodiment and the example shown below, In the range which does not deviate from the range which does not deviate from the Claim of this invention and its equivalent, it can change arbitrarily and can implement it. In addition, the same code|symbol is attached|subjected to the element same as the element already demonstrated, and the description may be abbreviate|omitted.

In the following description, the frontal direction of the image display device refers to the normal direction of the screen of the image display device unless otherwise specified, and specifically refers to the direction of 0° of declination and 0° of azimuth of the screen. .

In the following description, the color when the image display device is observed from the front direction may be simply referred to as "front color". Improving the front color means bringing the bluish black display state or the yellowish white display state when the image display device is viewed from the front direction close to the intended original black display state or white display state. it means.

In the following description, the term "plate" includes not only a rigid member, but also a member having flexibility, for example, a resin film, unless otherwise specified.

In the following description, the slow axis of the film or layer indicates the slow axis in the plane of the film or layer, unless otherwise specified.

In the following description, unless otherwise specified, the angle formed by the optical axis (slow axis, transmission axis, absorption axis, etc.) of each layer in a member including a plurality of layers is defined as the thickness direction of the layer. Shows the viewing angle.

In the following description, "circularly polarizing plate" includes not only circularly polarizing plate in a narrow sense but also elliptically polarizing plate.

In the following description, the "long" film refers to a film having a length of 5 times or more with respect to the width, and preferably has a length of 10 times or more, and specifically, the extent to which it is wound in a roll and stored or transported. A film with a length of There is no restriction|limiting in particular in the upper limit of the length of a film, For example, it can be made into 100,000 times or less with respect to a width|variety.

In the following description, the retardation Re in the in-plane direction of the layer is a value represented by Re = (nx - ny) x d, unless otherwise specified. Incidentally, the retardation Rth in the thickness direction of the layer is a value represented by Rth = [{(nx + ny)/2} - nz] × d, unless otherwise specified. Here, nx represents the refractive index of the direction which gives the largest refractive index as a direction (in-plane direction) perpendicular to the thickness direction of a layer. ny represents the refractive index of the direction orthogonal to the direction of nx as the said in-plane direction of a layer. nz represents the refractive index in the thickness direction of the layer. d represents the thickness of the layer. The measurement wavelength is 590 nm, unless otherwise stated.

In the following description, the directions of elements are "parallel", "vertical", and "orthogonal", unless otherwise specified, within a range that does not impair the effects of the present invention, for example, ±3°, ±2 The error within the range of ° or ±1 ° may be included.

[One. optical film]

The optical film which concerns on one Embodiment of this invention contains the resin layer A.

The resin layer A is formed of the resin A. Resin A which is the material of resin layer A contains 50 weight% or more of the alicyclic structure containing polymer with respect to resin A, and a ultraviolet absorber.

Further, the optical film has a light transmittance of 10% or less at a wavelength of 300 nm or more and 410 nm or less, a light transmittance of 80% or more at a wavelength of 430 nm, and an increase rate of the light transmittance at a wavelength of 410 nm or more and 420 nm or less, 4.0 %/nm or more.

[1.1. Resin A]

Resin A contains an alicyclic structure containing polymer. Here, the alicyclic structure-containing polymer is a polymer in which the structural unit of the polymer has an alicyclic structure. Resin containing such an alicyclic structure containing polymer is excellent in performance, such as transparency, dimensional stability, retardation expression property, and the stretchability at low temperature normally.

The alicyclic structure-containing polymer may be a polymer having an alicyclic structure in the main chain, a polymer having an alicyclic structure in the side chain, a polymer having an alicyclic structure in the main chain and side chain, and a mixture of two or more thereof in any ratio. have. Especially, the polymer which has an alicyclic structure in a main chain from a viewpoint of mechanical strength and heat resistance is preferable.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Especially, a cycloalkane structure and a cycloalkene structure are preferable from a viewpoint of a mechanical strength and heat resistance, and a cycloalkane structure is especially preferable especially.

The number of carbon atoms constituting the alicyclic structure per one alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, particularly Preferably it is 15 or less. When the number of carbon atoms constituting the alicyclic structure is within this range, the mechanical strength, heat resistance, and moldability of Resin A are highly balanced.

An alicyclic structure-containing polymer WHEREIN: The ratio of the structural unit which has an alicyclic structure can be selected according to the purpose of use of an optical film. The proportion of structural units having an alicyclic structure in the alicyclic structure-containing polymer is preferably 55% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and usually 100% by weight or more. can be done below. When the ratio of the structural unit having an alicyclic structure in the alicyclic structure-containing polymer is within this range, the transparency and heat resistance of the resin A become good.

Among the alicyclic structure-containing polymers, cycloolefin polymers are preferable. A cycloolefin polymer is a polymer which has a structure obtained by superposing|polymerizing a cycloolefin monomer. A cycloolefin monomer is a compound which has a ring structure formed from carbon atoms, and has a polymerizable carbon-carbon double bond in the ring structure. Examples of the polymerizable carbon-carbon double bond include a carbon-carbon double bond capable of polymerization such as ring-opening polymerization. In addition, examples of the ring structure of the cycloolefin monomer include monocyclic, polycyclic, condensed polycyclic, bridged ring, and polycyclic combinations thereof. Especially, a polycyclic cycloolefin monomer is preferable from a viewpoint of highly balancing characteristics, such as dielectric characteristic and heat resistance of the polymer obtained.

Preferred examples of the cycloolefin polymers include norbornene polymers, monocyclic cyclic olefin polymers, cyclic conjugated diene polymers, and hydrides thereof. Among these, norbornene-based polymers are particularly suitable because of their good moldability.

Examples of the norbornene-based polymer include a ring-opened polymer of a monomer having a norbornene structure and a hydride thereof; The addition polymer of the monomer which has a norbornene structure, and its hydride are mentioned. Further, examples of the ring-opened polymer of the monomer having a norbornene structure include a ring-opened homopolymer of one type of monomer having a norbornene structure, a ring-opened copolymer of two or more types of monomers having a norbornene structure, and norbornene and ring-opened copolymers of a monomer having a nene structure and other monomers copolymerizable therewith. In addition, as an example of the addition polymer of the monomer which has a norbornene structure, the addition homopolymer of one type of monomer which has a norbornene structure, the addition copolymer of two or more types of monomers which have a norbornene structure, and norbornene An addition copolymer with the monomer which has a nene structure, and other monomer copolymerizable with this is mentioned. Among these, the hydride of the ring-opened polymer of the monomer which has a norbornene structure is especially suitable from viewpoints of moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, etc.

Examples of the monomer having a norbornene structure include bicyclo[2.2.1]hepto-2-ene (common name: norbornene), tricyclo[4.3.0.1 ^2,5 ]deca-3,7-diene (common name) : dicyclopentadiene), 7,8-benzotricyclo[4.3.0.1 ^2,5 ]deca-3-ene (common name: methanotetrahydrofluorene), tetracyclo[4.4.0.1 ^2,5 .1 ^{7 ,10} ]dodeca-3-ene (common name: tetracyclododecene), and derivatives of these compounds (eg, those having a substituent on the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. In addition, these substituents are the same or different, and two or more may couple|bond with the ring. The monomer which has a norbornene structure may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

Examples of the polar group include a hetero atom and an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, an amide group, an imide group, a nitrile group, and a sulfonic acid group. As a polymer constituting the resin A, those containing such a polar group or those not containing a polar group can be preferably used.

Examples of the monomer having a norbornene structure and a monomer capable of ring-opening copolymerization include monocyclic olefins and derivatives thereof such as cyclohexene, cycloheptene and cyclooctene; Cyclic conjugated dienes, such as cyclohexadiene and cycloheptadiene, and its derivative(s) are mentioned. The monomer which has a norbornene structure and the monomer which can be ring-opening copolymerizable may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The ring-opening polymer of the monomer having a norbornene structure can be produced, for example, by polymerizing or copolymerizing the monomer in the presence of a ring-opening polymerization catalyst.

Examples of the monomer capable of addition copolymerization with the monomer having a norbornene structure include ?-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, and 1-butene, and derivatives thereof; cycloolefins such as cyclobutene, cyclopentene and cyclohexene and derivatives thereof; and non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, and 5-methyl-1,4-hexadiene. Among these, alpha-olefin is preferable and ethylene is more preferable. In addition, the monomer which has a norbornene structure, and the monomer which can be addition-copolymerized may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The addition polymer of the monomer which has a norbornene structure can be manufactured, for example by superposing|polymerizing or copolymerizing a monomer in presence of an addition polymerization catalyst.

Hydrogenated substances of the above-mentioned ring-opened polymers and addition polymers, for example, in the solution of these ring-opened polymers and addition polymers, in the presence of a hydrogenation catalyst containing a transition metal such as nickel or palladium, carbon-carbon unsaturated bonds , Preferably it can be produced by hydrogenation of 90% or more.

Examples of the monocyclic cyclic olefinic polymer include addition polymers of cyclic olefinic monomers having a monocyclic ring, such as cyclohexene, cycloheptene, and cyclooctene.

Examples of the cyclic conjugated diene-based polymer include a polymer obtained by cyclizing an addition polymer of a conjugated diene-based monomer such as 1,3-butadiene, isoprene and chloroprene; 1,2- or 1,4-addition polymers of cyclic conjugated diene-based monomers such as cyclopentadiene and cyclohexadiene; and hydrides thereof.

Commercially available resin can be used as an alicyclic structure containing polymer and resin containing it. Examples of commercially available resins include Zeonoa (manufactured by Nippon Zeon Corporation), Aton (manufactured by JSR Corporation), TOPAS (manufactured by Polyplastics Corporation), and APEL (manufactured by Mitsui Chemicals Corporation).

The content of the alicyclic structure-containing polymer in the resin A is usually 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, and usually 100% by weight or less. When the content of the alicyclic structure-containing polymer in the resin A is equal to or greater than the lower limit, the resin A can have excellent characteristics of the alicyclic structure-containing polymer.

Resin A may contain only 1 type of alicyclic structure containing polymer, and may contain it as a combination of 2 or more types of arbitrary ratios.

[1.2. UV absorber]

Resin A contains a ultraviolet absorber. A ultraviolet absorber means the agent which has one or more absorption maxima in wavelength 250nm or more and 400 nm or less in a light absorption spectrum. Here, the "agent" may be composed of one type of substance or a composition composed of two or more substances. In addition to having an absorption maximum at a wavelength of 400 nm or less, a ultraviolet absorber may have an absorption maximum in the range exceeding wavelength 400 nm. Resin A may contain only 1 type of ultraviolet absorber, and may contain it as a combination of 2 or more types of arbitrary ratios.

As the ultraviolet absorber, in the light absorption spectrum having a wavelength of 250 nm or more and 450 nm or less, it is preferable to use an agent having a maximum absorption at a wavelength of 400 nm or less. Thereby, an optical film can absorb an ultraviolet-ray effectively, and can protect components of an image display apparatus, such as a polarizer, from an ultraviolet-ray.

The light absorption spectrum of the ultraviolet absorber is measured by an ultraviolet/visible spectrometer (eg, "UV-2450" manufactured by Shimadzu Corporation), measuring wavelength: 250 nm to 450 nm, solvent: chloroform or methanol, concentration: 10 ppm, cell: optical path length It can be measured under the condition of a 1 cm quartz cell.

As the ultraviolet absorber, it is preferable to use an ultraviolet absorber whose wavelength of light exhibiting the maximum absorbance in the light absorption spectrum at a wavelength of 250 nm or more and 450 nm or less is in the range of 350 nm or more and 400 nm or less. Hereinafter, in the light absorption spectrum at a wavelength of 250 nm or more and 450 nm or less, a specific UV absorber having a wavelength of light exhibiting the maximum absorbance in the range of 350 nm or more and 400 nm or less may be referred to as UV absorber U1. By using the ultraviolet absorber in which the wavelength of the light which shows the maximum absorbance exists in the said range, it is an optical film WHEREIN: The light transmittance of wavelength 300nm or more and 410 nm or less can be suppressed low effectively. As a result, the amount of light with a wavelength of 300 nm or more and 410 nm or less emitted from the image display device can be effectively suppressed, and the color when the image display device is observed from the front can be effectively improved.

As the ultraviolet absorber U1, a ultraviolet absorber containing a compound having a sesamol structure and a benzotriazole structure can be used. As an example of the compound containing a sesamol structure and a benzotriazole structure, the compound I represented by the following general formula (1) is mentioned, The compound I is preferable.

[Formula 1]

In the general formula (1),

R ¹ is a hydrogen atom, a halogen atom, a (C1-C8) alkyl group, a (C1-C8) alkyloxy group, a hydroxy group, an amino group, a C1-C4 linear or branched mono-substituted amino group, a C1-C4 Linear or branched disubstituted amino group, nitro group, carboxy group, (C1 to C8)alkyloxycarbonyl group, hydroxy (C1 to C8)alkyl group, (C1 to C8)alkylcarbonyloxy (C1 to C8)alkyl group, carboxy (C1) to C3)alkyl group, (Cx)alkyloxycarbonyl(Cy)alkyl group, aryl group, acyl group, sulfo group, or cyano group. Here, the description of (Cm to Cn) immediately before “alkyl” means that the alkyl has m or more and n or less carbon atoms, and the description of (Cm) immediately before “alkyl” means that the alkyl is It means that the number of carbon atoms is m. x and y are each an integer of 1 or more, and x + y is 2 or more and 10 or less.

R ¹ is preferably a hydrogen atom or a (Cx)alkylcarbonyl(Cy)oxyalkyl group.

As a specific example of compound I, the compound mentioned in Japanese Patent No. 5416171 can be mentioned. Compound I can be prepared by the method described in Japanese Patent No. 5416171.

The content of the compound containing the sesamol structure and the benzotriazole structure in the ultraviolet absorber is preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 90% by weight or more, and 100% by weight. % or less.

The content of the ultraviolet absorber in the resin A is preferably 2.0% by weight or more, more preferably 4.0% by weight or more, still more preferably 6.0% by weight or more, preferably 30% by weight or less, more preferably 25% by weight or less, more preferably 20% by weight or less. By making the content rate of the ultraviolet absorber in the resin A fall within the above range, the ultraviolet absorber is suppressed from bleed out from the resin layer A, the image display device is effectively protected from ultraviolet rays, and the front color of the image display device is reduced can be improved

[1.3. Optional components included in Resin A]

Resin A may contain arbitrary components other than said ultraviolet absorber. Examples of such optional ingredients include antioxidants; light stabilizers; wax; nucleating agent; optical brighteners; inorganic fillers; coloring agent; flame retardant; flame retardant preparations; antistatic agent; plasticizer; near infrared absorbers; lubricant; filler; and any polymer other than the alicyclic structure-containing polymer; and the like. In addition, as an arbitrary component, you may use individually by 1 type, and may use it combining two or more types by arbitrary ratios.

[1.4. any layer that may be included in the optical film]

The optical film may contain the layer arbitrary other than the said resin layer A. As such an arbitrary layer, a contact bonding layer, the layer which has retardation, a hard-coat layer, etc. are mentioned.

[1.5. Characteristics of Optical Film]

(The light transmittance in wavelength 300nm or more and 410 nm or less)

As for the optical film, the light transmittance in wavelength 300nm or more and 410 nm or less is 10 % or less normally. That the light transmittance in wavelength 300nm or more and 410 nm or less is 10% or less means that the maximum value of the light transmittance in the range of wavelength 300nm or more and 410 nm or less is 10% or less. The light transmittance of the optical film at a wavelength of 300 nm or more and 410 nm or less is usually 10% or less, preferably 8% or less, more preferably 5% or less, and ideally 0%, but 0% or more or 0.01% or more. can be done with

When the light transmittance in the wavelength of 300 nm or more and 410 nm or less of an optical film is below the said upper limit, an image display apparatus can be effectively protected from an ultraviolet-ray, and the front color of an image display apparatus can be improved. In particular, the organic component contained in an organic electroluminescent element (organic EL element) is especially easy to deteriorate by the ultraviolet-ray of a long wavelength. Therefore, deterioration of the organic component contained in organic electroluminescent element can be suppressed effectively, and the lifetime of an organic electroluminescent display can be extended.

The light transmittance of the optical film can be measured using an ultraviolet visible near-infrared spectrophotometer (eg, "V-7200" manufactured by Nippon Kogyo Co., Ltd.).

(Light transmittance at a wavelength of 430 nm)

As for the optical film, the light transmittance in wavelength 430 nm is 80 % or more normally, Preferably it is 82 % or more, More preferably, it is 85 % or more, It is so preferable that it is high, but it is 100 % or less normally. When the light transmittance in the wavelength of 430 nm of an optical film is more than the said lower limit, it does not have a big influence on the color tone of an image display apparatus, but the front color of an image display apparatus can be improved. This effect is remarkable especially when the light emitting element contained in an image display apparatus is an organic electroluminescent element. As for the organic electroluminescent element used for an image display apparatus, there are many elements whose light emission intensity rises rapidly from wavelength 430 nm vicinity to the long wavelength side. Therefore, by making the light transmittance in wavelength 430nm of an optical film more than the said lower limit, the light of wavelength 430nm vicinity emitted from organic electroluminescent element becomes difficult to be absorbed by an optical film. As a result, the influence on the color of the image display device can be reduced.

(Increase rate of light transmittance in wavelength 410 nm or more and 420 nm or less)

The optical film has an increase rate R of light transmittance at a wavelength of 410 nm or more and 420 nm or less, usually 4.0%/nm or more, preferably 4.2%/nm or more, more preferably 4.5%/nm or more, particularly preferably 4.7 %/nm or more, preferably large, but may be 7.0%/nm or less.

The increase rate R (%/nm) is calculated by the following formula.

R(%/nm) = (T(420) - T(410))/(420 - 410)

In the above formula, T (420) is the light transmittance (%) at the wavelength of 420 nm of the optical film, T (410) is the light transmittance (%) at the wavelength of 410 nm of the optical film, the unit of the denominator is nm.

When the increase rate R of the optical film is equal to or greater than the lower limit, the optical film can transmit light having a wavelength of 430 nm at a high rate while effectively absorbing light having a wavelength of 300 nm or more and 410 nm or less. As a result, it is possible to effectively protect the image display apparatus from ultraviolet rays, and to improve the front color of the image display apparatus without greatly affecting the color tone of the image display apparatus.

(In-plane direction retardation of optical film)

The retardation Re (590) in the in-plane direction at a wavelength of 590 nm of the optical film is preferably 0.1 nm or more, more preferably 1 nm or more, still more preferably 2 nm or more, preferably 300 nm or less, more preferably is 270 nm or less, more preferably 250 nm or less. Thereby, the optical film can have a function as retardation films, such as a λ/4 plate.

It is preferable that in-plane direction retardation of an optical film has forward wavelength dispersion property. Specifically, Re(450)/Re(550) is preferably 1 or more, and more preferably larger than 1.

In the case where the in-plane directional retardation of the optical film has forward wavelength dispersion, it is possible to particularly improve the front color of the image display device.

[1.6. thickness of resin layer A]

The thickness of the resin layer A is preferably 3 µm or more, more preferably 5 µm or more, still more preferably 7 µm or more, preferably 50 µm or less, more preferably 40 µm or less, still more preferably 30 µm or less. When the thickness of the resin layer A is more than the said lower limit, an image display apparatus can be effectively protected from an ultraviolet-ray. In addition, it is possible to effectively improve the front color of the image display apparatus without greatly affecting the color of the image display apparatus. When the thickness of the resin layer A is below the said upper limit, the optical film containing the resin layer A can be thinned.

[1.7. Optical film of 1st Embodiment]

The optical film which concerns on 1st Embodiment is an optical film which consists of resin layer A. The resin layer A is formed of the said resin A. The optical film of the present embodiment is also described in [1.5. Characteristics of the optical film].

The optical film of this embodiment can be manufactured by a conventionally well-known method. For example, an optical film can be manufactured by the melt-molding method or the solution casting method, and the melt-molding method is preferable. The optical film may be further subjected to processing such as stretching and trimming.

[1.8. Optical film of 2nd embodiment]

The optical film which concerns on 2nd Embodiment further contains the resin layer B1 and the resin layer B2 in the resin layer A, the resin layer B1 is formed on one surface of the resin layer A, The other of the resin layer A The resin layer B2 is formed on the surface. The resin layer B1 is formed of a thermoplastic resin B1 having a content rate of the ultraviolet absorber of 3.0% by weight or less. The resin layer B2 is formed of the thermoplastic resin B2 having a content rate of the ultraviolet absorber of 3.0% by weight or less.

1 : is sectional drawing which shows typically the optical film which concerns on 2nd Embodiment. As shown in FIG. 1, the optical film 100 is the resin layer 102 as the resin layer B1 so that it may contact the resin layer 101 on one surface 101U of the resin layer 101 as the resin layer A. ) is formed. Moreover, on the other surface 102D of the resin layer 101, the resin layer 103 as resin layer B2 is formed so that the resin layer 101 may contact.

Thermoplastic resin B1 contains a thermoplastic polymer normally. Although there is no limitation in particular as a thermoplastic polymer, An alicyclic structure containing polymer is preferable. As the alicyclic structure-containing polymer, the same polymer as the alicyclic structure-containing polymer contained in the resin A can be selected.

The content of the alicyclic structure-containing polymer in the thermoplastic resin B1 is preferably 97.0% by weight or more, more preferably 98.0% by weight or more, and still more preferably 98.5% by weight or more. When the content rate of the alicyclic structure-containing polymer in the thermoplastic resin B1 is equal to or more than the lower limit, the thermoplastic resin B1 can have excellent characteristics of the alicyclic structure-containing polymer.

In the thermoplastic resin B1, the content of the ultraviolet absorber is usually 3.0% by weight or less, preferably 2.0% by weight or less, more preferably 1.5% by weight or less, still more preferably 1.0% by weight or less, particularly preferably is substantially 0% by weight, and most preferably contains no ultraviolet absorber. When the content rate of the ultraviolet absorber of thermoplastic resin B1 is below the said upper limit, it can suppress that a ultraviolet absorber bleeds out to the surface of an optical film.

The thermoplastic resin B1 may contain an optional component other than the above polymer. As the optional component, the same component as the optional component that the resin A may contain can be used.

Thermoplastic resin B2 contains a thermoplastic polymer normally. Although there is no limitation in particular as a thermoplastic polymer, An alicyclic structure containing polymer is preferable. As the alicyclic structure-containing polymer, the same polymer as the alicyclic structure-containing polymer contained in the resin A can be selected.

The content of the alicyclic structure-containing polymer in the thermoplastic resin B2 is preferably 97.0% by weight or more, more preferably 98.0% by weight or more, and still more preferably 98.5% by weight or more. When the content rate of the alicyclic structure-containing polymer in the thermoplastic resin B2 is equal to or greater than the lower limit, the thermoplastic resin B2 can have excellent characteristics of the alicyclic structure-containing polymer.

In the thermoplastic resin B2, the content of the ultraviolet absorber is usually 3.0% by weight or less, preferably 2.0% by weight or less, more preferably 1.5% by weight or less, still more preferably 1.0% by weight or less, particularly preferably is substantially 0% by weight, and most preferably contains no ultraviolet absorber. When the content rate of the ultraviolet absorber of thermoplastic resin B2 is below the said upper limit, it can suppress that a ultraviolet absorber bleeds out to the surface of an optical film.

Thermoplastic resin B2 may contain arbitrary components other than said polymer. As the optional component, the same component as the optional component that the resin A may contain can be used.

The thermoplastic resin B1 and the thermoplastic resin B2 may be different types of resins with different polymers, component ratios, physical properties, etc. included. However, it is preferable that thermoplastic resin B1 and thermoplastic resin B2 are the same resin from a viewpoint of suppressing the curl of an optical film, and a viewpoint of making manufacture of an optical film easy.

The thickness of the resin layer B1 is preferably 1 µm or more, more preferably 2 µm or more, preferably 15 µm or less, and more preferably 10 µm or less.

The range of the thickness of the resin layer B2 can be made the same as the range of the thickness of the resin layer B1. From a viewpoint of suppressing the curl of an optical film, it is preferable that resin layer B1 and resin layer B2 have mutually the same thickness.

The ratio ((B1 + B2)/A1) of the total thickness of the resin layer B1 and the resin layer B2 to the thickness of the resin layer A1 is preferably 1/25 or more, more preferably 1/10 or more, still more preferably Preferably it is 1/5 or more, Preferably it is 10/1 or less, More preferably, it is 6/1 or less, More preferably, it is 4/1 or less.

The optical film of the present embodiment is also described in [1.5. Characteristics of the optical film].

The optical film of this embodiment can be manufactured by a previously well-known manufacturing method. For example, the optical film of this embodiment can be manufactured by the melt molding method or the solution casting method.

It is preferable that it is manufactured by the melt molding method, and, as for the optical film of this embodiment, it is more preferable that it is manufactured by the co-extrusion method. Examples of the co-extrusion method include a co-extrusion T-die method, a co-extrusion inflation method, and a co-extrusion lamination method. Among them, the coextrusion T-die method is preferable.

The manufacturing method of the optical film by the coextrusion T-die method is demonstrated below.

The thermoplastic resin B1, the resin A, and the thermoplastic resin B2 are melted, and each is supplied to a T-die and co-extruded. By co-extrusion, the extruded film in which the layer of the thermoplastic resin B1, the layer of the resin A, and the layer of the thermoplastic resin B2 were laminated|stacked in this order is obtained. An elongate optical film is obtained by cooling an extruded film on a cooling roll normally, and then winding it up on a winding roll.

With respect to the optical film obtained by the said coextrusion method, you may further perform a process, such as extending|stretching and trimming, as needed.

[1.9. Use of optical film]

The optical film can be suitably used as an element of a polarizing plate, such as a polarizing plate protective film and (lambda)/4 plate. The polarizing plate containing an optical film can be used suitably as a polarizing plate couple|bonded with image display apparatuses, such as a liquid crystal display device and an organic electroluminescent display.

[2. Polarizer]

A polarizing plate according to an embodiment of the present invention includes the optical film disclosed above and a polarizer.

[2.1. polarizer]

As the polarizer, for example, a film of an appropriate vinyl alcohol polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol is dyed with a dichroic substance such as iodine and a dichroic dye, stretching treatment, crosslinking treatment, etc. Films in which proper treatment of Further, other examples of the polarizer include a polarizer having a function of separating polarized light into reflected light and transmitted light, such as a grid polarizer, a multilayer polarizer, and a cholesteric liquid crystal polarizer. Especially, the polarizer which consists of a polyvinyl alcohol resin film containing polyvinyl alcohol is preferable. Such a polarizer can transmit linearly polarized light when natural light is incident, and in particular, it is preferable that the light transmittance and the degree of polarization are excellent. Although 5 micrometers - 80 micrometers are common as for the thickness of a polarizer, it is not limited to this.

[2.2. optical film]

The optical film contained in the polarizing plate is [1. Optical film], it is the same as that of the optical film demonstrated in.

The optical film may be a film in which retardation Re(590) in the in-plane direction at a wavelength of 590 nm is 0.1 nm or more, or may be a film in which Re(590) is 300 nm or less.

For example, as an optical film, a polarizing plate can be made to function as a circularly polarizing plate by selecting the film which functions as (lambda)/4 plate.

The polarizer may be formed on either side of the one side and the other side of the optical film. For example, when the optical film further includes a resin layer B1 and a resin layer B2 in addition to the resin layer A like the optical film according to the second embodiment, the optical film is a polarizer, a resin layer B1, a resin layer A, and resin layer B2 may be provided in this order, and a polarizer, resin layer B2, resin layer A, and resin layer B1 may be provided in this order.

[2.3. Polarizing plate of 3rd embodiment]

In the polarizing plate which concerns on 3rd Embodiment, the optical film is formed on one surface of a polarizer. 2 : is sectional drawing which shows typically the polarizing plate which concerns on 3rd Embodiment. As shown in FIG. 2 , the polarizing plate 210 includes an optical film 211 and a polarizer 214 . The optical film 211 is formed on one surface 214U of the polarizer 214 so that the polarizer 214 may contact.

The optical film 211 is preferably a film functioning as a λ/4 plate.

When the optical film 211 is a film functioning as a λ/4 plate, the angle between the slow axis of the optical film 211 and the transmission axis of the polarizer is preferably 45° or an angle close thereto, specifically is preferably 45°±5°, more preferably 45°±3°, still more preferably 45°±1°. Thereby, the polarizing plate can function as a circularly polarizing plate.

In another embodiment, other layers, such as a contact bonding layer, may be formed between a polarizer and an optical film.

In another embodiment, a layer having a phase difference, such as a λ/2 plate, may be formed between the polarizer and the optical film.

[2.4. Polarizing plate of 4th embodiment]

The polarizing plate which concerns on 4th Embodiment further contains the optical film, a polarizer, and the retardation layer C. In the retardation layer C, retardation Re (590) in the in-plane direction at a wavelength of 590 nm is usually 70 nm or more, preferably 80 nm or more, more preferably 90 nm or more, and preferably 300 nm or less. The retardation layer C may be, for example, a layer having a function as a λ/4 plate or a layer having a function as a λ/2 plate.

3 : is sectional drawing which shows typically the polarizing plate which concerns on 4th Embodiment. As shown in FIG. 3 , the polarizing plate 220 includes an optical film 221 , a polarizer 224 , and a retardation layer 225 as the retardation layer C . On one surface 224U of the polarizer 224, the optical film 221 is formed so that the polarizer 224 may be contact|connected. The retardation layer 225 is formed on the other surface 224D of the polarizer 224 so as to be in contact with the polarizer 224 .

As for the optical film 221, it is preferable that the retardation Re (590) of the in-plane direction in wavelength 590nm is 0 nm or a value close to it, Specifically, Preferably it is less than 10 nm, More preferably, it is 5 nm or less. Thereby, it can suppress that the polarization state of the linearly polarized light which has passed through the polarizer 224 changes.

In another embodiment, other layers, such as a contact bonding layer, may be formed between a polarizer and an optical film. In another embodiment, other layers, such as a contact bonding layer, may be formed between a polarizer and retardation layer.

[3. image display device]

An image display apparatus according to an embodiment of the present invention includes the polarizing plate disclosed above and an image display apparatus. As the image display device, any type of image display device can be used. As an example of an image display apparatus, the organic electroluminescent display provided with the liquid crystal display device provided with a liquid crystal cell, and organic electroluminescent element is mentioned. Hereinafter, preferred embodiment of the image display device will be described.

[3.1. Image display device according to the fifth embodiment]

The image display apparatus of 5th Embodiment contains an optical film, a polarizer, and an image display element. 4 is a cross-sectional view schematically showing an image display device according to a fifth embodiment. The image display device 310 according to the present embodiment includes a polarizer 214 , an optical film 211 , and an image display element 316 in this order. The optical film 211 preferably has a function as a λ/4 plate as described above. Thereby, the polarizing plate 210 provided with the polarizer 214 and the optical film 211 can suppress reflection of external light.

In the image display device 310 , the optical film 211 absorbs at least a part of the ultraviolet rays that have passed through the polarizer 214 , so that the amount of the ultraviolet rays reaching the image display element 316 can be reduced. Therefore, the life of the image display device 310 can be extended.

In addition, the optical film 211 included in the image display device 310 effectively absorbs light having a wavelength of 300 nm or more and 410 nm or less among the light reflected by the image display element 316 . As a result, the front color of the image display device 310 can be improved by suppressing light having a wavelength of 300 nm or more and 410 nm or less from being visually recognized by being transmitted through the polarizer 214 to the outside. In addition, the optical film 211 can transmit light having a wavelength of 430 nm at a high rate. As a result, it is possible to improve the front color of the image display device without significantly affecting the color of the image display device 310 .

[3.2. Image display device according to the sixth embodiment]

The image display apparatus of 6th Embodiment contains an optical film, a polarizer, the retardation layer C, and an image display element. 5 is a cross-sectional view schematically showing an image display device according to a sixth embodiment. As shown in FIG. 5 , the image display device 320 according to the present embodiment includes an optical film 221 , a polarizer 224 , a retardation layer 225 as a retardation layer C, and an image display element 326 . included in order. The optical film 221 with which the image display device 320 is equipped absorbs at least a part of ultraviolet-ray from the outside. Thereby, the ultraviolet rays reaching the polarizer 224 can be reduced to protect the polarizer 224 from ultraviolet rays. Moreover, the optical film 221 effectively absorbs the light with a wavelength of 300 nm or more and 410 nm or less among the light reflected by the image display element 326. As shown in FIG. As a result, the front color of the image display device 320 can be improved by suppressing that light having a wavelength of 300 nm or more and 410 nm or less passes through the retardation layer 225 and passes through the polarizer 224 and is visually recognized. In addition, the optical film 221 can transmit light having a wavelength of 430 nm at a high rate. As a result, it is possible to improve the front color of the image display apparatus without significantly affecting the color of the image display apparatus 320 .

Example

Hereinafter, the present invention will be specifically described with reference to Examples. However, this invention is not limited to the Example shown below, In the range which does not deviate from the Claim of this invention and its equivalent range, it can change arbitrarily and implement it.

In the following description, "%" and "part" indicating the quantity are based on weight, unless otherwise specified. In addition, the operation demonstrated below was performed under conditions of normal temperature and normal pressure, unless otherwise indicated.

[Assessment Methods]

(Maximum absorption wavelength of UV absorber)

About the ultraviolet absorber, the light absorption spectrum in wavelength 250nm or more and wavelength 450nm or less was measured on the following conditions.

・Apparatus: Ultraviolet visible spectrophotometer (“UV-2450” manufactured by Shimadzu Corporation)

·Solvent: chloroform

Concentration: 10 ppm

Cell: 1 cm quartz

From the obtained light absorption spectrum, the maximum absorption wavelength was read.

(Glass Transition Temperature)

The glass transition temperature of the resin was measured using a differential scanning calorimeter (DSC). The temperature increase rate was 10°C/min.

(Light transmittance of the film)

The light transmittance of the optical film in wavelength 300nm - 450nm was measured using the ultraviolet-visible near-infrared spectrophotometer ("V-7200" by Nippon Kogyo Co., Ltd.). The data collection interval at the time of measurement was set to 1 nm.

From the obtained spectrum, the maximum light transmittance (%) in wavelength 300nm or more and 410 nm or less, and the light transmittance in wavelength 430nm were read.

The increase rate R of the light transmittance at a wavelength of 410 nm or more and 420 nm or less is obtained from the light transmittance T (420) (%) at a wavelength of 420 nm and the light transmittance T (410) (%) at a wavelength of 410 nm, from the following formula calculated.

R(%/nm) = (T(420) - T(410))/(420 - 410)

(thickness of resin layer A)

In Examples 1-3 and Comparative Examples 1-3, the thickness of the film was measured with the contact-type film thickness meter, and it was set as the thickness of the resin layer A.

In Examples 4 to 8 and Comparative Example 4, the thickness of the resin layer A was measured by cutting the film in the thickness direction and observing the cross section with an optical microscope.

(Method for measuring in-plane retardation Re (590) of film)

In-plane retardation Re(590) in the wavelength of 590 nm of the film was measured by "AxoScan" manufactured by AXOMETRICS at a measurement wavelength of 590 nm.

(Lightfastness test)

Examples 1-8 and the optical film of Comparative Examples 1-4 were used and the light resistance test by irradiation of an ultraviolet-ray was done. Irradiation was performed using the super xenon weather meter (SX75: made by Suga Test Co., Ltd.) on ^{conditions of 72 W/m<2>} , black panel temperature 63 degreeC, and humidity 50%RH. The optical film was taken out after 300 hours of irradiation, and the retention of the absorbance in wavelength 410nm was calculated|required according to the following formula.

Retention (%) = (A ₁ /A ₀ ) × 100

Here, A ₀ is the absorbance at a wavelength of 410 nm of the optical film before the light resistance test, A ₁ is the absorbance at a wavelength of 410 nm of the optical film after the light resistance test, A ₀ and A ₁ are the above-mentioned ultraviolet visible near-infrared spectroscopy. It measured using the photometer ("V-7200" by Nippon Kogyo Co., Ltd.).

From the obtained value of the retention of absorbance, light resistance was judged on the following reference|standard.

A: The retention of absorbance is 80% or more.

B: The retention of absorbance is less than 80%.

(color display performance)

Evaluation of color display performance was performed as follows.

The optical film to be evaluated was pasted together on the visual recognition side of a commercially available organic electroluminescent image display apparatus (Galaxy-S, the Samsung company make).

The organic electroluminescent image display apparatus was made into a white display state, and the hue was observed from the front direction of a display surface using the viewing angle measurement evaluation apparatus ("ErgoScope" by Autronic-MELCHERS). The color display performance was evaluated according to the following criteria.

A: It was uniform throughout and no color change was observed.

B: It was almost uniform as a whole, and the change of color was hardly seen.

C: A change in color was seen on the image.

[Preparation Example 1 Compound (a1): Synthesis of 6-(2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol]

[Formula 2]

Equipped with an Allihn condenser, a thermometer, and a stirring device in a 200 ml four-necked flask, 15.2 g (0.110 mol) of orthonitroaniline, 25.4 g (0.162 mol) of 62.5% sulfuric acid were put and dissolved, and while stirring, 85 ml of water was added. To this, 21.7 g (0.113 mol) of a 36% aqueous sodium nitrite solution was added dropwise at 3 to 7°C, followed by stirring at the same temperature for 2 hours to obtain 147 g of an aqueous diazonium salt solution. Equipped with a tube condenser, a thermometer, and a stirring device in a 500 ml four-necked flask, 120 ml of methanol, 4.6 g (0.115 mol) of sodium hydroxide, 6.2 g (0.058 mol) of sodium carbonate, and 15.2 g (0.110 mol) of sesamol were put and mixed, An aqueous solution of a diazonium salt was added dropwise at 3 to 7°C, followed by stirring at the same temperature for 4 hours. The pH was adjusted to 4 with 62.5% sulfuric acid, and the resulting precipitate was filtered, washed with water and dried to obtain 40.3 g of red crystals. This 40.3 g was repulped with an aqueous isopropyl alcohol solution to obtain 22.0 g of 6-(2-nitrophenylazo)benzo[1,3]dioxol-5-ol as red crystals.

A 300 ml 4-neck flask was equipped with a tube condenser, a thermometer and a stirring device, 22.0 g (0.077 mol) of this red crystal, 100 ml of isopropyl alcohol, 50 ml of water, 3.7 g (0.093 mol) of sodium hydroxide, 0.2 g of hydroquinone, 60 % hydrazine hydrate 3.6g (0.043 mol) was added, stirred at 50-55° C. for 1 hour, pH was adjusted to 7 with 62.5% sulfuric acid, and the resulting precipitate was filtered, washed with water, and dried, and 6-(2H-benzotriazole). 18.4 g of -2-yl)benzo[1,3]dioxol-5-ol-N-oxide was obtained.

Equipped with a tube condenser, a thermometer, and a stirring device in a 1000 ml 4-neck flask, 18.4 g (0.068 mol) of N-oxide, 360 ml of toluene, 120 ml of water, and 8.9 g (0.136 mol) of zinc powder were added and mixed, and 62.5% sulfuric acid was added. 31.9 g (0.203 mol) was added dropwise at 70 to 75° C. for 1 hour, followed by stirring at the same temperature for 1 hour. It left still to separate and remove the aqueous layer of the lower layer, wash with 100 ml of warm water, add 0.6 g of activated carbon, and decolorize by stirring under reflux. After heat filtration, 180 ml of toluene was recovered from the filtrate, cooled to 5° C., and the precipitated crystals were filtered, washed with 30 ml of toluene, dried at 60° C., and yellow crystals (melting point 195° C.) 9.9 g of phosphorus compound (a1) was obtained. The yield of compound (a1) from orthonitroaniline was 35%.

Moreover, as a result of measuring the ultraviolet-visible absorption spectrum of compound (a1), the maximum absorption wavelength was 367 nm, and the absorbance in wavelength 367nm was 20900.

[Preparation Example 2 Compound (a2): Synthesis of 6-(5-methylcarbonyloxyethyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol]

[Formula 3]

A 200 ml 4-neck flask was equipped with a tube condenser, a thermometer, and a stirring device, and 2.0 g of 6-(5-hydroxyethyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol (0.0067 mol), 50 ml of toluene, 1.6 g (0.0266 mol) of acetic acid, and 0.1 g (0.0010 mol) of methanesulfonic acid were added, and dehydrated under reflux at 110 to 115°C for 4 hours. After washing 3 times with 50 ml of warm water, 0.1 g of activated carbon was added, and the mixture was decolorized by stirring under reflux. After filtration at hot time, the precipitated crystals were filtered, washed with 10 ml of toluene, and dried at 60° C. to obtain 2.2 g of compound (a2). The yield from 6-(5-hydroxyethyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol was 96%.

Moreover, as a result of measuring the ultraviolet-visible absorption spectrum of compound (a2), the maximum absorption wavelength was 368 nm, and the absorbance in wavelength 368 nm was 22500.

[Example 1]

(Preparation of Resin A)

Cycloolefin resin C1 ("Zeonoa" manufactured by Nippon Zeon Corporation, glass transition temperature Tg=126°C) containing 99% by weight or more of a cycloolefin polymer as an alicyclic structure-containing polymer was dried. 92 parts of dried cycloolefin resin C1 and the compound (a1) (a compound containing a sesamol structure and a benzotriazole structure, 8 parts of compound) whose R<^1> is a hydrogen atom was mixed using the twin screw extruder, and resin A1 was obtained.

(Manufacture of film)

A single screw extruder equipped with a gear pump and filter was prepared. Resin A1 was put into this single screw extruder and melted. The molten resin A1 was passed through a gear pump followed by a filter, extruded from a T-die, and passed through a cooling roll to obtain an optical film having a thickness of 20 µm. The obtained optical film was evaluated by the said method.

[Example 2]

In manufacture of resin A, except having changed the following matter, it carried out similarly to Example 1, the 20-micrometer-thick optical film was obtained, and this was evaluated.

- The amount of cycloolefin resin C1 was changed to 94 parts.

- Compound (a2) (a compound containing a sesamol structure and a benzotriazole structure as an ultraviolet absorber, prepared in Preparation Example 2 above, in place of 8 parts of compound (a1), in the formula (1), R ^{6 parts of compounds in which 1} is a methylcarbonyloxyethyl group) were used.

[Example 3]

In manufacture of resin A, the following matter was changed and except having adjusted the manufacturing conditions of the film, it carried out similarly to Example 1, the 15 micrometers-thick optical film was obtained, and this was evaluated.

- In place of 92 parts of cycloolefin resin C1, 93 parts of cycloolefin resin C2 ("Aton" manufactured by JSR Corporation) containing 99% by weight or more of a cycloolefin polymer as an alicyclic structure-containing polymer was used.

- The amount of compound (a1) was changed to 7 parts.

[Example 4]

As the thermoplastic resin B1 and the thermoplastic resin B2, the cycloolefin resin C1 was prepared. As the resin A, the resin A1 was prepared. Three single screw extruders equipped with gear pumps and filters were prepared. In three single screw extruders, the resin C1, the resin A1, and the resin C1 were respectively charged, melted, and passed through a gear pump and then a filter. Then, the molten resin C1, resin A1, and resin C1 are co-extruded from a T-die having a three-layer flow path, and passed through a cooling roll, (layer of resin C1/layer of resin A1/layer of resin C1) ) to obtain an optical film having a thickness of 34 µm and evaluated it. The thickness of the layer of resin A1 was 20 micrometers.

[Example 5]

As the thermoplastic resin B1 and the thermoplastic resin B2, 98.5 parts of the dried cycloolefin resin C1 and the compound (a1) as an ultraviolet absorber prepared in Production Example 1 above (in the formula (1), R ¹ is a hydrogen atom) The resin obtained by mixing 1.5 parts of phosphorus compound) using a twin screw extruder was prepared. As resin A, resin A2 in which the following items were changed in the manufacturing method of the said resin A1 was prepared.

- The amount of cycloolefin resin C1 was changed to 93 parts.

- The amount of compound (a1) was changed to 7 parts.

Using these resins, except having adjusted the manufacturing conditions of a film, it carried out similarly to Example 4, and obtained the 34-micrometer-thick optical film, and evaluated this. The thickness of the layer of resin A2 was 20 micrometers.

[Example 6]

As Resin A, Resin A3 was prepared in the same manner as in Preparation of Resin A1, except that the following items were changed.

- The amount of cycloolefin resin C1 was changed to 95 parts.

- The amount of compound (a1) was changed to 5 parts.

Resin A3 was used instead of resin A1, and except having adjusted the manufacturing conditions of a film, it carried out similarly to Example 4, and obtained the 90-micrometer-thick optical film, Then, this optical film was biaxially stretched apparatus (Toyo Seiki) It stretched using EX10-B) by a manufacturing company, and the 58-micrometer-thick optical film was obtained, and this was evaluated. The thickness of the layer of resin A3 was 30 micrometers.

[Example 7]

As Resin A, Resin A4 was prepared in the same manner as in Preparation of Resin A1, except that the following items were changed.

- The amount of cycloolefin resin C1 was changed to 89 parts.

- The amount of compound (a1) was changed to 11 parts.

Resin A4 was used instead of resin A1, and except having adjusted the manufacturing conditions of a film, it carried out similarly to Example 4, to obtain an optical film with a thickness of 35 micrometers, Then, this optical film was biaxially stretched apparatus (Toyo Seiki) It stretched using EX10-B) manufactured by a manufacturing company, and a 24 micrometer-thick optical film was obtained, and this was evaluated. The thickness of the layer of resin A4 was 10 micrometers.

[Example 8]

Except having adjusted the manufacturing conditions of the film, it carried out similarly to Example 4, obtained the 40-micrometer-thick optical film, Then, this optical film was stretched using the biaxial stretching apparatus (EX10-B by Toyo Seiki Seisakusho) Thus, an optical film having a thickness of 27 µm was obtained, and this was evaluated. The thickness of the layer of resin A1 was 13 micrometers.

[Comparative Example 1]

In manufacture of resin A, the following matter was changed and except having adjusted the manufacturing conditions of the film, it carried out similarly to Example 1, and obtained the 20-micrometer-thick optical film, and evaluated this.

- Instead of the cycloolefin resin C1, polyethylene terephthalate ("SA-8339P" manufactured by Unitica Co., Ltd.) was used.

- Instead of the compound (a1), a triazine-based ultraviolet absorber ("ADEKA STAB (registered trademark) LA-F70" manufactured by ADEKA) was used.

[Comparative Example 2]

In manufacture of resin A, except having changed the following matter, it carried out similarly to Example 1, the 20-micrometer-thick optical film was obtained, and this was evaluated.

- In place of 92 parts of cycloolefin resin C1, 90.5 parts of polyethylene terephthalate ("SA-8339P" manufactured by Unitica Corporation) was used.

・In place of 8 parts of compound (a1), 8 parts of a triazine-based ultraviolet absorber (“ADEKASTAB (registered trademark) LA-F70” manufactured by ADEKA) and 8 parts of an indole-based compound (“BONASORB (registered trademark) UA” manufactured by Orient Chemical Industry Co., Ltd.) -3911") 1.5 parts were used.

[Comparative Example 3]

In manufacture of resin A, the following matter was changed and except having adjusted the manufacturing conditions of the film, it carried out similarly to Example 1, and obtained the 20-micrometer-thick optical film, and evaluated this.

- The amount of cycloolefin resin C1 was changed to 98.5 parts.

- 1.5 parts of an indole compound ("BONASORB (trademark) UA-3911" manufactured by Orient Chemical Industry Co., Ltd.) was used instead of 8 parts of compound (a1).

[Comparative Example 4]

As Resin A, Resin A5 was prepared in the same manner as in Preparation of Resin A1, except that the following items were changed.

- The amount of cycloolefin resin C1 was changed to 98.5 parts.

- 1.5 parts of an indole compound ("BONASORB (trademark) UA-3911" manufactured by Orient Chemical Industry Co., Ltd.) was used instead of 8 parts of compound (a1).

Resin A5 was used instead of resin A1, except having adjusted the manufacturing conditions of the film, it carried out similarly to Example 4, the 34 micrometers optical film was obtained, and this was evaluated. The thickness of the layer of resin A5 was 20 micrometers.

The results of Examples and Comparative Examples are shown in the table below. The symbol in the following table|surface shows the following meaning.

C1: Cycloolefin resin (“Zeonoa” manufactured by Nippon Zeon)

C2: Cycloolefin resin ("Aton" manufactured by JSR)

a1: Compound (a1) prepared in Preparation Example 1

a2: Compound (a2) prepared in Preparation Example 2

LA-F70: "ADEKA STAB (registered trademark) LA-F70" manufactured by ADEKA

UA-3911: manufactured by Orient Chemical Industry Co., Ltd. "BONASORB (registered trademark) UA-3911"

Tmax (300-410): Maximum light transmittance (%) at a wavelength of 300 nm or more and 410 nm or less

T (430): light transmittance (%) at a wavelength of 430 nm

Increase rate R: Increase rate R of the light transmittance in wavelength 410nm or more and 420 nm or less (%/nm)

The light transmittance in a wavelength of 300 nm or more and 410 nm or less is 10% or less, the light transmittance in a wavelength of 430 nm is 80% or more, and the increase rate of the light transmittance in a wavelength of 410 nm or more and 420 nm or less is 4.0%/nm or more, Example, The single-layer optical film of 1, 2, and 3 can cut the light of the ultraviolet-ray contained in external light efficiently, without inhibiting the light from an organic electroluminescent image display apparatus. Thereby, while protecting the display element etc. of an organic electroluminescent image display apparatus from an ultraviolet-ray, it turns out that a clear display is possible without an image display apparatus almost changing a display color.

In addition, the light transmittance in a wavelength of 300 nm or more and 410 nm or less is 10% or less, the light transmittance in a wavelength of 430 nm is 80% or more, and the increase rate of the light transmittance in a wavelength of 410 nm or more and 420 nm or less is 4.0%/nm or more, The multilayer optical film of Examples 4, 5, 6, 7, and 8 can cut the light of the ultraviolet-ray contained in external light efficiently, without inhibiting the light from an organic electroluminescent image display apparatus. Thereby, while protecting the display element etc. of an organic electroluminescent image display apparatus from an ultraviolet-ray, it turns out that a clear display is possible without an image display apparatus changing almost a display color.

100: optical film
101: resin layer
101U: Cotton
102: resin layer
102D: Cotton
103: resin layer
210: polarizing plate
211: optical film
214: polarizer
214U: Cotton
220: polarizer
221: optical film
224: polarizer
224D: Cotton
224U: Cotton
225: retardation layer
310: image display device
316: image display element
320: image display device
326: image display element

Claims (8)

An optical film comprising a resin layer A, comprising:
The resin layer A is formed of the resin A,
The resin A contains 50% by weight or more of an alicyclic structure-containing polymer and a UV absorber,
The optical film has a light transmittance of 10% or less at a wavelength of 300 nm or more and 410 nm or less, a light transmittance of 80% or more at a wavelength of 430 nm, and an increase rate of the light transmittance at a wavelength of 410 nm or more and 420 nm or less, 4.0% /nm or more,
optical film. The method of claim 1,
Further comprising a resin layer B1 and a resin layer B2,
The resin layer B1 is formed on one surface of the resin layer A,
The resin layer B2 is formed on the other surface of the resin layer A,
The resin layer B1 is formed of a thermoplastic resin B1 having a UV absorber content of 3.0 wt% or less,
The said resin layer B2 is formed from the thermoplastic resin B2 whose content rate of a ultraviolet absorber is 3.0 weight% or less, The optical film. 3. The method of claim 2,
An optical film, which is a coextruded film. 4. The method according to any one of claims 1 to 3,
The optical film, wherein the ultraviolet absorber includes a compound having a sesamol structure and a benzotriazole structure. 5. The method according to any one of claims 1 to 4,
The optical film whose retardation Re(590) of the in-plane direction in wavelength 590nm is 0.1 nm or more. The polarizing plate containing the optical film in any one of Claims 1-5, and a polarizer. 7. The method of claim 6,
The polarizing plate further including the retardation layer C whose retardation Re (590) of the in-plane direction in wavelength 590 nm is 70 nm or more. The image display apparatus containing the polarizing plate of Claim 6 or 7.

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