KR20150009154A - Polarizing plate and display devices comprising the same - Google Patents
Polarizing plate and display devices comprising the same Download PDFInfo
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- KR20150009154A KR20150009154A KR1020130083263A KR20130083263A KR20150009154A KR 20150009154 A KR20150009154 A KR 20150009154A KR 1020130083263 A KR1020130083263 A KR 1020130083263A KR 20130083263 A KR20130083263 A KR 20130083263A KR 20150009154 A KR20150009154 A KR 20150009154A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/14—Protective coatings, e.g. hard coatings
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
- G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
- G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3083—Birefringent or phase retarding elements
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133528—Polarisers
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/13363—Birefringent elements, e.g. for optical compensation
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Abstract
The present invention relates to a polarizing plate and an image display apparatus having the polarizing plate and a protective film on both sides of the polarizer and the polarizer, wherein one of the protective films has a surface treatment layer on its surface, A pencil having a hardness of 5B or more of a pencil having a hardness of 5B or more of the pencil connected to the surface of the film is contacted and reciprocated and the weight of the weight is increased to 300 g or more at the time of occurrence of cracking in the surface treatment layer, And an image display apparatus having the polarizer.
Description
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate and an image display apparatus having the polarizing plate. More particularly, the present invention relates to a polarizing plate having improved crack resistance and an image display apparatus having the same.
Polymer films typified by cellulose ester, polyester, polycarbonate, cycloolefin polymer, vinyl polymer, and polyimide are used for optical films such as retardation films and polarizing plates. Since these polymers can produce films superior in planarity and uniformity, they are widely used as films for optical use.
However, the optical films are frequently subjected to excessive pressure partially or totally in the process of being applied to the product and actually used. If an external force more than a certain level is applied to the surface of the polymer material, surface damage will occur. Such surface damage accelerates the damage of the material itself, thereby losing the original function of the polymer material and accelerating the replacement time.
In particular, recent optical polymer films are subjected to various surface treatments in order to add optical functionality. Such surface treatment may cause cracking or breakage when a certain amount of external force is applied to the polymer film.
In this respect, it is necessary to specifically investigate the hardness of the polymer film to be used. The pencil hardness method is most widely known as the hardness measurement method.
However, the known pencil hardness method has a disadvantage in that the hardness of the polymer film can not be determined by a specific quantitative value.
On the other hand, transparent protective films such as triacetylcellulose (TAC) films have been widely used for optical films such as polarizing plates and retardation films used in image display devices. However, since the TAC film is relatively expensive, an acrylic film such as PMMA has recently been proposed as an alternative to the TAC film. Korean Patent Publication No. 2011-0117243 discloses a technique using an acrylic resin as a protective film of a polarizing plate.
However, since acrylic films have rigid properties, they are fragile even under a weak pressure.
An object of the present invention is to provide a polarizing plate capable of minimizing damage due to external impact by improving cracking property.
Another object of the present invention is to provide a polarizing plate having a crack resistance, which is quantitatively measured according to a novel cracking property measurement method, of not less than a predetermined value and which is excellent in crack resistance.
It is still another object of the present invention to provide a polarizing plate having an antiglare layer with improved crack resistance and excellent antiglare property.
1. A polarizing plate comprising a polarizer and a protective film on both surfaces of the polarizer, wherein the first protective film has a surface treatment layer on its surface, and a pencil lead having a hardness of 5B or more, Wherein the weight of the weight weight is 300 g or more at the time when the weight of the weight weight is increased and the surface treatment layer is broken.
2. The protective film as described in 1 above, wherein the protective film is at least one selected from the group consisting of polyester resins, cellulose resins, polycarbonate resins, acrylic resins, styrene resins, polyolefin resins, amide resins, imide resins, Based resin, a sulfone-based resin, a polyetheretherketone-based resin, a sulfided polyphenylene-based resin, a vinyl alcohol-based resin, a vinylidene chloride-based resin, a vinylbutyral-based resin, an allylate-based resin, a polyoxymethylene- Wherein the polarizing plate comprises at least one selected from the following.
3. The polarizing plate according to item 1 above, wherein the protective film comprises at least one selected from the group consisting of a cellulose resin, an acrylic resin and a polyolefin resin.
4. The polarizing plate of 1 above, wherein the first protective film comprises an acrylic resin.
5. The polarizing plate according to item 1 above, wherein the surface treatment layer is at least one selected from the group consisting of an antiglare layer, an antistatic layer, an scratch resistant layer, an antifouling layer, a hard coat layer, a high refractive index layer and a low refractive index layer.
6. The polarizing plate of 5 above, wherein the surface treatment layer is an antiglare layer.
7. The polarizing plate according to 1 above, wherein the surface treatment layer is formed from a composition for forming a surface treatment layer comprising urethane (meth) acrylate and polyester (meth) acrylate.
8. The polarizer of claim 7, wherein the urethane (meth) acrylate is 2 to 6 functional and the polyester (meth) acrylate is 2 to 5 functional.
9. The polarizer according to claim 8, wherein the 2- to 5-functional polyester (meth) acrylate is contained in an amount of 20 to 50 parts by weight based on 100 parts by weight of the solid content in the composition.
10. The polarizing plate according to claim 8, wherein the 2- to 6-functional urethane (meth) acrylate is contained in an amount of 45 to 85 parts by weight based on 100 parts by weight of solids in the composition.
11. The polarizing plate according to item 1 above, wherein the second protective film is an optical compensation film.
12. An image display device comprising the polarizing plate of any one of 1 to 11 above.
The polarizing plate of the present invention has a cracking property measured according to the novel cracking property measurement method provided by the present invention and has a predetermined value (300 g) or more, so that crack resistance suitable for commercialization can be expressed by a specific numerical standard.
In addition, the polarizing plate of the present invention has a surface treatment layer containing polyurethane acrylate and polyester acrylate, so that it can have excellent crack resistance.
Further, the surface treatment layer according to the present invention can be used as a layer having various optical functions. For example, when used as an antiglare layer, the anti-cracking property of the polarizing plate can be remarkably improved.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing an example of crack property measurement according to the present invention. Fig.
The present invention relates to a polarizing plate having excellent crack resistance suitable for commercial use.
Hereinafter, the present invention will be described in more detail.
The polarizing plate of the present invention comprises a polarizer and a protective film on both sides of the polarizer, and one of the protective films has a surface treatment layer on its surface.
Polarizer
The polarizer according to the present invention can be applied without any particular limitation in the art. For example, a polarizer is one in which a dichroic dye is adsorbed and oriented on a stretched polymer film.
The polymer film constituting the polarizer is not particularly limited as long as it is a film which can be dyed with a dichroic substance such as iodine. Specifically, the polymer film may be a polyvinyl alcohol film, an ethylene-vinyl acetate copolymer film, an ethylene-vinyl alcohol copolymer film , Cellulose films, partially saponified films thereof, and the like; Or a dehydrated polyvinyl alcohol film, a dehydrochloric acid-treated polyvinyl alcohol film, and the like. Of these, a polyvinyl alcohol-based film is preferable because it has an excellent effect of enhancing the uniformity of the degree of polarization in the plane and is excellent in dye affinity for a dichroic substance.
More preferably, it may be a polyvinyl alcohol-based film obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Other monomers copolymerizable with vinyl acetate include acrylamide monomers having an unsaturated carboxylic acid type, an unsaturated sulfonic acid type, an olefin type, a vinyl ether type, and an ammonium group.
The polyvinyl alcohol resin may also be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polymerization degree of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000.
Such a polyvinyl alcohol-based resin film is used as the original film of the polarizer. The method of forming the film of the polyvinyl alcohol-based resin is not particularly limited, and a known method can be used. The thickness of the original film is not particularly limited, and may be, for example, 10 to 150 mu m.
The polarizer is produced by using a disc method using a known method. For example, swelling, dyeing, crosslinking, stretching, and the like, and the order and the number of the steps are not particularly limited. The final draw ratio is about 4.5 to 7.0 times, preferably about 5.0 to 6.5 times.
Protective film
The polarizing plate of the present invention has protective films on both sides of the polarizer.
As the respective protective films usable in the present invention, films excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy and the like can be used. Specific examples include polyester resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; Cellulose-based resins such as diacetylcellulose and triacetylcellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, cyclo- or norbornene-structured polyolefins, ethylene-propylene copolymers; Vinyl chloride resin; Amide resins such as nylon and aromatic polyamide; Imide resin; Polyether sulfone type resin; Sulfone based resin; Polyether ether ketone resin; A sulfided polyphenylene resin; Vinyl alcohol-based resin; Vinylidene chloride resins; Vinyl butyral resin; Allylate series resin; Polyoxymethylene type resin; Epoxy resin, and the like, and a film composed of the blend of the thermoplastic resin may also be used. Further, a film made of a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, or silicone or a film made of an ultraviolet curable resin may be used. The same material may be used for both sides of the protective film on both sides of the polarizer, or another material may be used. A cellulose resin, an acrylic resin and a polyolefin resin can be preferably used. In order to exhibit the anti-cracking effect and synergistic effect of the surface treatment layer of the present invention, an acrylic resin is more preferable.
The content of the thermoplastic resin in the polarizer protective film is preferably 50 to 100% by weight, preferably 50 to 99% by weight, more preferably 60 to 98% by weight, and most preferably 70 to 97% by weight. When the content is less than 50% by weight, the inherent high transparency of the thermoplastic resin may not be sufficiently exhibited.
Such a transparent protective film may contain one or more suitable additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment and a colorant.
Further, if necessary, the protective film may be surface-treated. Examples of the surface treatment include a chemical treatment such as an alkaline treatment including a dry treatment such as a plasma treatment, a corona treatment, a primer treatment, and a saponification treatment.
Further, if necessary, at least one of the protective films on both sides of the polarizer may further have optical functionality. For example, an optical compensation film in which a liquid crystal compound or a polymer compound thereof is aligned on the surface of a substrate, a reflection type polarization separation film which transmits a certain kind of polarized light and reflects polarized light of a property opposite to that, An optical compensation film including a cyclic polyolefin resin, a reflecting film having a reflecting function on the surface, a transflective film having both a reflecting function and a transmitting function, and the like. In this respect, Or may be a laminate of two or more layers. The optically functional protective film may preferably be an optical compensation film. When an optical compensation film is adopted, it is preferable that the opposite surface protective film on the side where the surface treatment layer is formed is an optical compensation film.
In addition, the polarizing plate of the present invention may be a polarizing plate in which an adhesive layer and a release film are sequentially laminated on a second protective film which is a protective film opposite to the first protective film. In this case, in the later-described crack property measurement, contact and reciprocation of the pencil lead are performed on the surface of the release film which is the opposite side of the first protective film.
Surface treatment layer
The polarizing plate of the present invention has a surface treatment layer on any one of the protective films (first protective film).
The surface treatment layer according to the present invention is a surface treatment layer excellent in crack resistance. Specifically, a pencil having a hardness of 5B or more of a pencil having a weight added on its surface is contacted and reciprocated, and the weight of the weight is increased. When the weight of the surface treatment layer is 300 g or more, And is a surface-treated layer having properties. The cracking property measuring method will be described later in the cracking property measuring method.
The surface treatment layer having excellent crack resistance of the present invention can be formed of a composition for forming a surface treatment layer containing urethane (meth) acrylate and polyester (meth) acrylate. In the present invention, (meth) acrylate refers to acrylate, methacrylate or both.
The urethane (meth) acrylate can be prepared by reacting a compound having a polyfunctional (meth) acrylate having a hydroxyl group in the molecule and an isocyanate group in the presence of a catalyst according to a method known in the art. Specific examples of the polyfunctional (meth) acrylate having a hydroxyl group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl (Metha) acrylate mixture, and a mixture of dipentaerythritol penta / hexa (meth) acrylate, a mixture of pentaerythritol tetra (meth) acrylate and caprolactone ring-opening hydroxyacrylate. Specific examples of the compound having an isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, Diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) cyclohexane, trans-1,4-cyclohexane diisocyanate, Diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene-1, Diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenyl isocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate And trifunctional isocyanate derived from trimethane propanol adduct toluene diisocyanate It may be at least one member selected from the group consisting of a carbonate.
The polyester (meth) acrylate can be prepared by reacting a polyester polyol and an acrylic acid according to methods known in the art. The polyester (meth) acrylate may be, for example, a polyester acrylate, a polyester diacrylate, a polyester tetraacrylate, a polyester hexaacrylate, a polyester pentaerythritol triacrylate, a polyester pentaerythritol tetraacryl And polyester pentaerythritol hexaacrylate, but is not limited to these.
The urethane (meth) acrylate and the polyester (meth) acrylate are preferably contained in a total amount of 92 to 99 parts by weight based on 100 parts by weight of the solid content in the composition according to the present invention. If the content is less than 92 parts by weight, cracking may occur due to over-curing. If the content is more than 99 parts by weight, physical properties may be deteriorated due to uncured.
In one embodiment of the present invention, the composition for forming a surface treatment layer may comprise a mixture of 2 to 5 functional polyester (meth) acrylate and 2 to 6 functional urethane (meth) acrylate.
2 to 5-functional polyester (meth) acrylate is preferably contained in an amount of 20 to 50 parts by weight based on 100 parts by weight of the solid content in the composition. If the content of the 2 to 5 functional polyester (meth) acrylate is less than 20 parts by weight, the cracking property is deteriorated. If the content is more than 50 parts by weight, mechanical property deterioration may occur.
It is also preferable that the 2 to 6-functional urethane (meth) acrylate is contained in an amount of 45 to 85 parts by weight based on 100 parts by weight of the solid content of the composition. If the content of the 2 to 6-functional urethane (meth) acrylate is less than 45 parts by weight, the mechanical properties may deteriorate. If the content is more than 85 parts by weight, crack property may be deteriorated.
If necessary, the composition for forming a surface treatment layer according to the present invention may further comprise a photocurable monomer.
Examples of the monomer include photo-curable functional groups such as (meth) acryloyl groups, vinyl groups, styryl groups, allyl groups, and other monomers used in the art having unsaturated groups in the molecule, A monomer having a diene group can be used.
Examples of the monomer having a (meth) acryloyl group include neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di Acrylate, trimethylolpropane tri (meth) acrylate, trimethylol ethane tri (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (Meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, Acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acrylate, tripentaerythritol hexa (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, hydroxyethyl (Meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobutyl (meth) acrylate, , Phenoxyethyl (meth) acrylate, and isobonol (meth) acrylate, but are not limited thereto.
In particular, the use of the photo-curable monomer in the range of the content of the urethane (meth) acrylate in the mixture with the polyester (meth) acrylate can be used to increase the workability and compatibility of the photocurable coating composition , An equivalent level of cracking characteristics can be obtained.
The composition for forming a surface treatment layer according to the present invention may further comprise a photoinitiator and a solvent.
The photoinitiator can be used without limitation as long as it is used in the art. Specifically, the photoinitiator may be at least one selected from the group consisting of hydroxy ketones, aminoketones, and hydrogen recycling photoinitiators.
Examples of the photoinitiator include 2-methyl-1- [4- (methylthio) phenyl] 2-morpholinepropanone-1, diphenylketone, benzyldimethylketal, 2- 4-hydroxycyclophenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4- Quinolone acetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexyl phenyl ketone, benzophenone, and diphenyl (2,4,6-trimethylbenzoyl) phosphine Oxide, and the like.
The photoinitiator is preferably contained in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the composition. If the amount of the photoinitiator is less than 0.05 part by weight, the curing speed of the composition is slow and uncured, resulting in poor mechanical properties. If the amount is more than 10 parts by weight, cracking may occur due to overaging.
The solvent is not particularly limited and can be used without limitation as long as it is used in the technical field. Specific examples thereof include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and diacetone alcohol, esters such as methyl formate, methyl acetate, ethyl acetate, ethyl lactate and butyl acetate, nitromethane, Nitrogen-containing compounds such as pyridine, pyrrolidone and N, N-dimethylformamide, ethers such as diisopropyl ether, tetrahydrofuran, dioxane and dioxolane, methylene chloride, chloroform, trichloroethane and tetrachloroethane Halogenated hydrocarbons, and other materials such as dimethyl sulfoxide, propylene carbonate, and 2-methoxyethanol. The solvents exemplified above may be used alone or in combination of two or more. More specifically, at least one selected from the group consisting of methyl acetate, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and 2-methoxyethanol may be used.
The solvent is preferably contained in an amount of 0.1 to 85 parts by weight based on 100 parts by weight of the composition. If the content of the solvent is less than 0.1 parts by weight, the viscosity is high and the workability is poor. When the content of the solvent is more than 85 parts by weight, a long time is required in the drying and curing process.
If necessary, the surface treatment layer of the present invention may further have additional functionality in addition to crack resistance. The additional functionality is not particularly limited as long as it is a layer that can be provided on the protective film of the polarizer. For example, at least one or more of an antiglare layer, an antistatic layer, an scratch layer, an antifouling layer, a hard coat layer, a high refractive index layer, and a low refractive index layer may be selected. Preferably, it may be an antiglare layer.
Therefore, in order to further provide additional functionality, the surface treatment layer of the present invention may further include necessary components in each case. For example, it may further include anti-glare particles, antistatic agents, antifouling agents, and the like, but the present invention is not limited thereto, and may include components known in the art depending on additional functionality.
If necessary, the composition for forming a surface treatment layer may contain, in addition to the above-mentioned components, components commonly used in the art such as antioxidants, UV absorbers, light stabilizers, thermal polymerization inhibitors, leveling agents, An activator, a lubricant, and the like.
Crack Castle How to measure
The polarizing plate of the present invention has excellent crack resistance, and the present invention provides a crack evaluation method capable of quantitatively evaluating crack resistance.
The cracking property evaluation method according to the present invention is a method of evaluating cracking property in which a pencil lead of a pencil connected in an additional weight on an opposite surface of a first protective film having a surface treatment layer is contacted and reciprocated, The weight at the time of occurrence of cracking is judged as the degree of cracking of the surface-treated polarizing plate.
The pencil hardness method used in the past to measure the cracking property is a method of measuring the hardness of a measurement surface by whether or not a pencil lead is brought into contact with and moved on a surface to be hardened to cause scratches on the surface. Further, according to the conventional pencil hardness method, the hardness of the measurement surface is determined by the hardness of the pencil lead that generates the scratch. Therefore, the hardness of the measurement surface is only grasped by the degree of hardness of the pencil lead, and more specific and quantitative determination is impossible.
On the other hand, FIG. 2 schematically shows an embodiment of a method for measuring the cracking property of a polarizing plate having a surface treatment layer according to the present invention.
In the present invention, the cracking property is measured by not contacting the surface of the polarizing plate to be measured with the surface treatment layer but contacting the opposite surface with a pencil lead and reciprocating motion. The inventors of the present invention have found that the present invention is based on the fact that, when a surface-treated surface of a polarizing plate is directly pressed against a surface of a polarizing plate, the surface of the polarizing plate is pressed on the opposite surface, Therefore, the present invention can measure a more accurate degree of breakage of the surface-treated face of the polarizing plate.
Further, the present invention can change the pressure applied to the polarizing plate to be measured by connecting a weight to a pencil to be used, and confirm the breaking (cracking) behavior of the polarizing plate according to the change of the weight. The weight of the weights connected to the pencil is increased while the pencil is reciprocated to determine the weight at the time when cracks are generated in the surface-treated surface as the degree of cracking of the surface-treated surface of the polarizer, . Thus, the cracking property of the polarizing plate can be evaluated quantitatively.
The pencil used in the present invention is not particularly limited, and for example, a pencil used in the pencil hardness method may be used in the present invention. A more specific example is the pencil specified in KS G 2603, Republic of Korea.
In the present invention, the surface of the second protective film opposite to the first protective film on which the surface treatment layer of the polarizing plate is formed is brought into contact with the pencil lead of the pencil to reciprocate. Since the weight of the pencil is further connected, the polymer film is pressed by the pressure corresponding thereto, and when a certain level of pressure is applied, a crack phenomenon occurs on the surface-treated surface of the polarizer, which is the opposite side of the surface with which the pencil lead is in contact .
As described above, the weight at the time of occurrence of cracks is judged as the degree of cracking of the polarizing plate having the surface treatment layer. For more precise measurement, it is desirable to reduce the degree of increase in weight. For example, it may be increased by 100 g, preferably by 50 g, more preferably by 10 g, but is not limited thereto. The degree of increase can be appropriately selected in consideration of the required accuracy of the measurement, the measurement time required, and the like.
The number of reciprocations of the pencil lead is not particularly limited either. It is possible to reciprocate about 3 to 10 times in consideration of the specific type of material to be measured and the time required for measurement, but the present invention is not limited thereto.
The angle of the pencil lead with the contact surface can be determined as needed. For example, it may have an angle of 45 ° to 90 ° with respect to the contacting surface. In addition, the pencil lead may be prepared to be exposed to about 3 to 6 mm. It is preferable to polish the end of the pencil lead in contact with the measurement object flat to maintain the reliability of measurement.
In the present invention, the cracking property can be further classified according to the hardness of the pencil lead. 5H, 4H, 3H, 2H, H, F, HB, B, 2B, 3B, 4B, 5B, 6B, 7B, 8B, and 9B. Therefore, for example, if the polymer film to be measured is classified according to the hardness of the pencil lead used for cracking measurement such as 100 g of a certain polymer film in 100 g of H pencil and 100 g of other polymer film in HB pencil, It can be determined finely.
The polarizing plate of the present invention is characterized in that cracks are generated at 300 g or more when measured with a pencil lead having a hardness of 5B or more according to the above crack evaluation method. When the pencil hardness measured with a pencil hardness of 5B or more is less than 300 g, there is a problem that the polarizing plate is fragile during handling. In the present invention, the better the crack resistance, the better, so the upper limit of the weight is not particularly limited. For example, 5,000 g when measured with a pencil having a hardness of 5B or higher, but this is merely an example, and not limited thereto.
Thus, since the polarizing plate of the present invention has a cracking property of 300 g or more, there is little possibility of breakage in the manufacturing process of the image display apparatus using the polarizing plate of the present invention or in transportation or storage.
Image display device
The polarizing plate of the present invention can be included as an element of an image display apparatus. Examples of the image display device include a liquid crystal display device, an OLED, and a PDP. Other components and assemblies of the image display apparatus can adopt those well known in the art, and therefore, the image display apparatus of the present invention is not particularly limited, except that the polarizing plate of the present invention described above is used, , ≪ / RTI >
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.
Manufacturing example : Surface treatment layer ≪ Preparation of composition for forming &
A composition for forming a surface treatment layer was prepared in terms of the composition (based on solid content) shown in Table 1 below (parts by weight). As the solvent, a mixed solvent of isopropyl alcohol and methyl ethyl ketone in a weight ratio of 1: 1 was used.
PETA: pentaerythritol triacrylate
PEA: polyester tetraacrylate (tetrafunctional, Mw = 1800)
Repellent particles: acrylic particles (average particle size = 4 탆)
Photoinitiator: I-184 (Shiba)
Example 1-5 and Comparative Example 1-2: Polarizing plate manufacturing
As a first protective film, a polyacrylic resin film (thickness: 80 탆, trade name: "Technoroy S001", manufactured by Sumitomo Chemical Co., Ltd.) was used. On one surface of the first protective film, a surface treatment layer (The antiglare layer) was formed by irradiating with UV light to form a surface treatment layer (antiglare layer) (the coating thickness was 5 占 퐉 for Preparation Examples 1-6 and 8 占 퐉 for Preparation Example 7) ).
As a second protective film, a polycyclic olefin-based film (thickness: 50 mu m, trade name "ZEONOR film ", manufactured by Nippon Zeon) was used.
An epoxy adhesive was applied between the polyvinyl alcohol polarizer and the two protective films to a thickness of 1 to 5 탆, and the adhesive was cured by irradiating with UV light, and then an acrylic adhesive was applied thereto to a thickness of 20 탆 To prepare a polarizing plate as shown in Table 2 below.
Test Example
The polarizer thus prepared was subjected to the following tests, and the results are shown in Table 2 below.
One. Crack Castle evaluation
<Evaluation method>
The prepared polarizing plate was prepared in a size of 5 cm * 5 cm, and the surface treatment layer of the first protective film was brought into contact with the substrate of the measuring instrument and fixed with a glass tape.
The pencil was prepared with a cutter knife at a pencil diameter of 5 to 6 mm, and the end of the pencil was flattened and polished smoothly. At this time, the pencil was a pencil (5B) manufactured by Mitsubishi.
The pencil was brought into contact with the center of the second protective film at an angle of 45 DEG with respect to the surface of the second protective film. The weight of the initial weight connected to the pencil was set at 100 g, and the pencil moving speed was set at 30 rpm.
After the setting was completed, the substrate was moved from right to left to draw the pencil lead on the surface of the second protective film. After 3 cm, the test was stopped and the test was performed 3 times in total. The weight was evaluated by increasing the weight by 100 g to the point at which cracks or substrate breakage occurred.
<Evaluation Criteria>
A three-wavelength lamp was used to determine whether cracks and substrate breakage were visually observed. In the case where cracks or sagging were not recognized, presence or absence of cracks was determined using a loupe or an optical microscope. Cracks at the starting point of dropping the pencil were not included in the determination.
2. Pencil Hardness
<Evaluation method>
The surface of the first protective film of the prepared polarizing plate, that is, the surface treatment layer, was subjected to a 500 g load using a pencil hardness tester (PHT, Kobo Scientific Co., Ltd.) to measure the pencil hardness. The pencil was manufactured by Mitsubishi Corporation and measured five times per pencil hardness.
<Evaluation Criteria>
If the number of cigarettes is two or more, it is judged to be defective, and the pencil hardness is indicated by a pencil before the defective.
The above evaluation method is in conformity with the JIS K 3600 evaluation method.
3. Mandrel
<Evaluation method>
The polarizing plate is cut so that the transmission axis direction is 25 mm and the absorption axis direction is 250 mm.
The diameter of the mandrel rod was prepared as follows.
2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 25, 32 mm
The surface of the mandrel rod was placed on the outside and folded.
<Evaluation Criteria>
The diameter of the mandrel without surface cracking was confirmed at OK level when it was confirmed by transmission through a three-wavelength lamp.
The ROD used in the above evaluation conforms to the ISO 1519 standard.
4. Steel wool
<Evaluation method>
Scratch resistance was tested by reciprocating ten times under 1 kg / (2 cm x 2 cm) using a steel wool tester (WT-LCM100, Korea Protec Co., Ltd.) and evaluated based on the following criteria.
<Evaluation Criteria>
A: 0 scratches
A ': 1 to 10 scratches
B: 11 to 20 scratches
C: 21 to 30 scratches
D: More than 31 scratches
5. Haze
It was measured according to JIS K 7136 method.
(Antiglare layer)
(陸)
According to Table 2, it can be confirmed that the polarizing plate of the present invention has an excellent crack resistance of 300 g or more.
As a conventional evaluation method, it was not possible to judge the cracking property of the polarizing plates of Examples and Comparative Examples by pencil hardness or steel wool method, and it was found that there was some difference in the mandrel method between Examples and Comparative Examples However, the difference was not large, and the examples and the comparative examples showed the same values, respectively, so that no specific difference could be found.
However, according to the crack evaluation method according to the present invention, not only the difference between the embodiment and the comparative example is obvious but also it is understood that the minute difference of each polarizing plate can be clearly understood.
Claims (12)
The first protective film has a surface treatment layer on its surface,
A pencil having a hardness of not less than 5B of a pencil connected to the opposite side of the first protective film is contacted and reciprocated and the weight of the weight is increased so that the weight of the surface treatment layer at the time of occurrence of cracking is not less than 300 g Polarizer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020130083263A KR20150009154A (en) | 2013-07-16 | 2013-07-16 | Polarizing plate and display devices comprising the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020130083263A KR20150009154A (en) | 2013-07-16 | 2013-07-16 | Polarizing plate and display devices comprising the same |
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| Publication Number | Publication Date |
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| KR20150009154A true KR20150009154A (en) | 2015-01-26 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170111422A (en) * | 2016-03-28 | 2017-10-12 | 주식회사 에스티이케이 | Display protection film for shock absorbing |
| KR20170118356A (en) * | 2016-04-15 | 2017-10-25 | 엘지디스플레이 주식회사 | Liquid crystal display device |
-
2013
- 2013-07-16 KR KR1020130083263A patent/KR20150009154A/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170111422A (en) * | 2016-03-28 | 2017-10-12 | 주식회사 에스티이케이 | Display protection film for shock absorbing |
| KR20170118356A (en) * | 2016-04-15 | 2017-10-25 | 엘지디스플레이 주식회사 | Liquid crystal display device |
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