KR20150130721A - Ultra thin polarizing plate and image display device comprising the same - Google Patents
Ultra thin polarizing plate and image display device comprising the same Download PDFInfo
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- KR20150130721A KR20150130721A KR1020140057665A KR20140057665A KR20150130721A KR 20150130721 A KR20150130721 A KR 20150130721A KR 1020140057665 A KR1020140057665 A KR 1020140057665A KR 20140057665 A KR20140057665 A KR 20140057665A KR 20150130721 A KR20150130721 A KR 20150130721A
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- Prior art keywords
- polarizer
- polarizing plate
- sensitive adhesive
- pressure
- weight
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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
-
- 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
-
- 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
- B32B2307/00—Properties of the layers or laminate
- B32B2307/40—Properties of the layers or laminate having particular optical properties
- B32B2307/42—Polarizing, birefringent, filtering
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Polarising Elements (AREA)
Abstract
The present invention relates to an ultra-thin polarizing plate, and more particularly, to a polarizing plate having a protective film on one surface of a polarizer, a pressure-sensitive adhesive layer formed on the other surface of the surface to which the protective film is adhered, And an antistatic agent containing an antistatic agent, thereby providing an antistatic property and preventing loss of iodine anions in the polarizer, thereby exhibiting excellent optical characteristics and durability.
Description
The present invention relates to an ultra-thin polarizing plate and an image display apparatus having the same.
BACKGROUND ART [0002] A liquid crystal display device (LCD) is used for various purposes such as a notebook computer, a mobile phone, and a liquid crystal TV, and is generally composed of a liquid crystal cell containing a liquid crystal and a polarizer, do.
The polarizing plate used in the liquid crystal display is generally a polyvinyl alcohol (PVA) resin film arranged in a predetermined direction, and a polarizer (or a polarizing plate) having a thickness of about 30 탆 in which an iodine compound or a dichroic polarizing material is adsorbed and oriented, Polarizing film "), and on both sides of the polarizer, first and second polarizer protective films of about 80 μm thickness, typified by triacetyl cellulose (TAC), are laminated through an adhesive, respectively And has a multilayer structure in which a pressure sensitive adhesive layer to be laminated on the liquid crystal cell is laminated on one side of the polarizer protective film.
Since each constituent film of such a polarizing plate is made of a material having a different molecular structure and composition, it has different physicochemical properties. Polarizers, in which PVA is a stretched film, shrink or swell under high temperature and humidity, so that the constituting films of the polarizing plate are bent or easily fall off, and bubbles are generated.
Especially recently, the market for slim liquid crystal display devices such as a slim large wall-mounted TV, a mobile type computer, a car TV, a display of a car navigation system, and a mobile phone is rapidly expanding. Accordingly, a thin and lightweight ultra thin polarizing plate (UTP) has been required to thin the entire module of a liquid crystal display device.
As a method for producing such an ultra-thin polarizer, a method of thinning the thickness of the polarizer or the polarizer protective film and a method of removing one layer of the polarizer protective film in the configuration of the polarizer have been proposed. However, in the conventional polarizing plate described above, the polarizing plate shrinks or expands under high temperature and humidity, so that the constituent films of the polarizing plate are not durable or lifted from the liquid crystal cell, and the polarizing plate is stretched in the stretching direction There was a problem that it tore easily. In addition, there is a problem that a foreign substance is mixed into an optical member due to a static electricity problem generated when the liquid crystal cell is bonded to the liquid crystal cell, thereby causing defects. Furthermore, since the UTP polarizer is in direct contact with the iodine-based polarizer and the pressure-sensitive adhesive, the degree of freedom of iodine due to the lowering of the crosslink density due to the penetration of moisture under the conditions of durability, there is a concern that the optical characteristic is deteriorated by -out. Accordingly, in the production of an ultra-thin polarizing plate, improvement in optical durability as well as durability and antistatic property of a pressure-sensitive adhesive are urgently required.
It is an object of the present invention to provide an ultra-thin polarizer capable of exhibiting excellent optical characteristics under severe conditions of high temperature and high humidity.
It is an object of the present invention to provide an ultra-thin polarizer capable of exhibiting excellent durability even in severe conditions of high temperature and high humidity.
It is an object of the present invention to provide a polarizing plate capable of exhibiting excellent antistatic performance.
It is another object of the present invention to provide an image display apparatus having the above polarizing plate.
1. A protective film is attached to one surface of a polarizer and a pressure-sensitive adhesive layer is formed on the other surface of the surface to which the protective film is attached,
Wherein the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition comprising an acrylic copolymer and an antistatic agent containing an iodine anion.
2. The ultra-thin polarizer according to 1 above, wherein the antistatic agent further comprises an organic cation having at least three alkyl groups of 3 to 20 carbon atoms in the molecule.
3. The antistatic agent according to 1 above, wherein the antistatic agent is at least one selected from compounds represented by the following general formulas (1) to (3):
[Chemical Formula 1]
(2)
(3)
(Wherein X is a sulfur atom, a nitrogen atom or a phosphorus atom,
R 1 , R 2 , R 3 , R 1 'and R 2 ' are each independently an alkyl group having 3 to 20 carbon atoms,
When X is a sulfur atom, R 4 is a non-bonded electron pair,
When X is a nitrogen atom or phosphorus atom, R 4 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms,
R 3 'and R 4 ' each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms).
4. The ultra-thin polarizer according to 1 above, wherein the antistatic agent is contained in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the acrylic copolymer.
5. An image display device comprising the polarizing plate of any one of 1 to 4 above.
INDUSTRIAL APPLICABILITY The present invention suppresses the loss of iodine anions of a polarizer and can exhibit excellent optical characteristics even under severe conditions of high temperature and high humidity.
The present invention can exhibit excellent durability even under severe conditions of high temperature and high humidity.
Further, the present invention can exhibit excellent antistatic performance.
The present invention relates to an ultra-thin polarizing plate, and more particularly, to a polarizing plate having a protective film on one surface of a polarizer, a pressure-sensitive adhesive layer formed on the other surface of the surface to which the protective film is adhered, And an antistatic agent containing an antistatic agent, thereby providing an antistatic property and preventing loss of iodine anions in the polarizer, thereby exhibiting excellent optical characteristics and durability.
Hereinafter, the present invention will be described in more detail.
Ultra Thin Polarizing Plate refers to a direct bonding of a polarizer and a pressure-sensitive adhesive layer without a separate protective film to realize a slimmed image display device. However, such an ultra-thin polarizing plate easily penetrates moisture and foreign matter into the inside of the polarizer under severe conditions of high temperature and high humidity, and the cross-linking density of the polarizer is lowered, and the durability of the polarizer shrinks and expands, . In particular, there is a problem that the degree of freedom of iodide ion increases in the polarizer, and the iodine ion easily bleeds out from the polarizer, thereby significantly deteriorating optical characteristics.
However, the ultra-thin polarizing plate according to the present invention has an antistatic property by forming a pressure-sensitive adhesive layer using an antistatic agent containing an iodine anion, thereby preventing the loss of iodine anions in the polarizer even under severe conditions of high temperature and high humidity, And optical properties.
More specifically, the KI ion salt used in the polarizer manufacturing process is subjected to an ion exchange reaction with the ionic antistatic agent MX contained in the pressure-sensitive adhesive under the moisture-resistant condition, so that KI in the polarizer moves to the pressure-sensitive adhesive layer, Of MX in the polarizer layer moves to the polarizer layer, which results in a decrease in the concentration of iodine anion in the polarizer and a decrease in the polarization degree of the polarizer due to the decrease in the concentration of iodine anion. INDUSTRIAL APPLICABILITY By using MI (iodine-based antistatic agent) as an antistatic agent in the pressure-sensitive adhesive layer in order to suppress lowering of the concentration of iodine anions in the polarizer, the concentration of iodine anions in the polarizer can be prevented from being lowered I will. Further, by making the molecular structure of the MI cation bulky, the ion exchange reaction between KI and MI can be minimized, and the lowering of the polarization degree can be further suppressed.
The ultra-thin polarizer according to an embodiment of the present invention includes a polarizer, a protective film attached to one surface of the polarizer, and a pressure-sensitive adhesive layer formed on the other surface to which the protective film is attached.
< Polarizer >
The polarizer of the present invention uses iodine as a dichroic dye in which a dichroic dye is adsorbed and oriented on a stretched polyvinyl alcohol resin film.
The polyvinyl alcohol-based resin constituting the polarizer can be obtained by saponifying a polyvinyl acetate-based 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 of the present invention is produced by continuously uniaxially stretching a polyvinyl alcohol-based film in an aqueous solution, staining with a dichroic dye and adsorbing, treating with an aqueous solution of boric acid, and washing and drying.
The uniaxial stretching of the polyvinyl alcohol film may be performed before dyeing, concurrently with dyeing, or may be performed after dyeing. If uniaxial stretching is carried out after dyeing, it may be carried out before the boric acid treatment, or may be carried out during the boric acid treatment. Of course, it is also possible to perform uniaxial stretching in a plurality of such steps. For uniaxial stretching, other rolls or rolls of different circumferences may be used. The uniaxial stretching may be either dry stretching in air or wet stretching in the state of being swollen with a solvent. The stretching ratio is usually 4 to 8 times.
As a step of dyeing a stretched polyvinyl alcohol film with a dichroic dye, for example, a method of immersing a polyvinyl alcohol film in an aqueous solution containing a dichroic dye can be used. Iodine is used as the dichroic dye. It is preferable that the polyvinyl alcohol film is pre-immersed in water before dyeing to swell.
In the dyeing step, a method of dying and dyeing a polyvinyl alcohol-based film into an aqueous solution for dyeing usually containing iodine and potassium iodide can be used. Usually, the content of iodine in an aqueous solution for dyeing is 0.01 to 1 part by weight with respect to 100 parts by weight of water (distilled water), and the content of potassium iodide is 0.5 to 20 parts by weight with respect to 100 parts by weight of water. The temperature of the aqueous solution for dyeing is usually 20 to 40 占 폚, and the immersion time (dyeing time) is usually 20 to 1,800 seconds.
The step of treating the dyed polyvinyl alcohol film with boric acid can be carried out by immersing it in an aqueous solution containing boric acid. The content of boric acid in an aqueous solution containing boric acid is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight based on 100 parts by weight of water. Since iodine is used as the dichroic dye, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The content thereof is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, based on 100 parts by weight of water. The temperature of the boric acid-containing aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C., and more preferably 60 to 80 ° C. The immersing time is usually 60 to 1,200 seconds, preferably 150 to 600 seconds, Preferably 200 to 400 seconds.
After the boric acid treatment, the polyvinyl alcohol film is usually washed with water and dried. The washing treatment can be carried out by immersing the boric acid-treated polyvinyl alcohol-based film in water. The water temperature of the water treatment is usually 5 to 40 占 폚, and the immersion time is usually 1 to 120 seconds. After washing with water, the polarizer can be obtained. The drying treatment can be usually carried out using a hot air dryer or a far infrared ray heater. The drying treatment temperature is usually 30 to 100 占 폚, preferably 50 to 80 占 폚, and the drying time is usually 60 to 600 seconds, preferably 120 to 600 seconds.
The thickness of the polarizer according to the present invention is not particularly limited, but may be, for example, 5 to 80 탆.
<Protection film>
The protective film of the present invention is formed only on the other surface of the surface on which the pressure-sensitive adhesive layer of the polarizer is formed, and is not used as a base material when the pressure-sensitive adhesive layer is formed.
The kind of the protective film is not particularly limited as long as it is excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, etc., and examples thereof include polyester films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate; Cellulose-based films such as diacetylcellulose and triacetylcellulose; Polycarbonate film; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene-based films such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin-based films such as polyethylene, polypropylene, cyclo-based or norbornene-structured polyolefin, and ethylene propylene copolymer; Polyimide-based films; Polyethersulfone-based films; A sulphone film, or the like can be used, but the present invention is not limited thereto.
If necessary, a surface treatment layer such as a hard coating layer, an antireflection layer, and an antiglare layer may be further laminated on the protective film. Specifically, the hard coat layer serves to prevent the surface of the polarizing plate from being damaged, and may be formed of, for example, an acrylic or silicone resin having excellent adhesiveness and hardness. The antireflection layer is for preventing reflection of external light on the surface of the polarizing plate, and may be formed by a known method. In addition, the antiglare layer is for preventing the visibility that occurs when external light is reflected on the surface of the polarizing plate. For example, the antiglare layer may be formed by a roughening method such as a sandblast method or an embossing method, or by mixing transparent ultrafine particles A method in which a composition is applied and cured, or the like.
The thickness of the protective film is not particularly limited, but may be 10 to 200 占 퐉, preferably 10 to 150 占 퐉.
< The pressure- >
The pressure-sensitive adhesive layer of the present invention is directly bonded to the polarizer without a separate protective film, so that the polarizer can be made thinner and lighter. Further, it is formed of a pressure-sensitive adhesive composition comprising an antistatic agent containing an iodine anion, so that the polarizing plate according to the present invention can exhibit excellent durability even under severe conditions of high temperature and high humidity.
Pressure-sensitive adhesive composition
The pressure-sensitive adhesive composition used in the present invention includes an acrylic copolymer and an antistatic agent containing an iodine anion.
The acrylic copolymer used in the present invention preferably contains a (meth) acrylate monomer having an alkyl group having 1-12 carbon atoms, and a polymerizable monomer having a crosslinkable functional group.
Here, (meth) acrylate means acrylate and methacrylate.
Examples of the (meth) acrylate monomer having an alkyl group having 1-12 carbon atoms include n-butyl (meth) acrylate, 2-butyl (meth) acrylate, (Meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (Meth) acrylate, n-butyl acrylate, nonyl (meth) acrylate, decyl (meth) acrylate and lauryl Or a mixture thereof. These may be used alone or in combination of two or more.
The polymerizable monomer having a cross-linkable functional group is a component for imparting durability and cutability by reinforcing the cohesive strength or adhesive strength of the pressure-sensitive adhesive composition by chemical bonding, and examples thereof include monomers having a hydroxy group, monomers having a carboxyl group, monomers having an amide group, Monomers having a tertiary amine group, and the like. These monomers may be used alone or in admixture of two or more.
Examples of the monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl Hydroxypropyleneglycol (meth) acrylate, hydroxyalkylene glycol having 2 to 4 carbon atoms in the alkylene group (e.g., methoxyethyl (meth) acrylate, Hydroxybutyl vinyl ether, 8-hydroxyoctyl vinyl ether, 9-hydroxynonyl (meth) acrylate, 4-hydroxybutyl vinyl ether, Vinyl ether, and 10-hydroxydecyl vinyl ether, among which 4-hydroxybutyl vinyl ether is preferable.
Examples of the monomer having a carboxyl group include monovalent acids such as (meth) acrylic acid and crotonic acid; Dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid, and monoalkyl esters thereof; 3- (meth) acryloylpropionic acid; A succinic anhydride ring-opening addition adduct of 2-hydroxyalkyl (meth) acrylate in which the alkyl group has 2 to 4 carbon atoms, anhydrous succinic ring opening adduct of a hydroxyalkylene glycol (meth) acrylate having 2 to 4 carbon atoms in the alkylene group , And compounds obtained by ring-opening addition of succinic anhydride to a caprolactone adduct of 2-hydroxyalkyl (meth) acrylate in which the alkyl group has 2-3 carbon atoms. Of these, (meth) acrylic acid is preferable.
Examples of the monomer having an amide group include (meth) acrylamide, N-isopropyl acrylamide, N-tertiary butyl acrylamide, 3-hydroxypropyl (meth) acrylamide, 4-hydroxybutyl (Meth) acrylamide, 8-hydroxyoctyl (meth) acrylamide, and 2-hydroxyethylhexyl (meth) acrylamide. Of these, (meth) acrylamide is preferable.
Examples of the monomer having a tertiary amine group include N, N- (dimethylamino) ethyl (meth) acrylate, N, N- (diethylamino) ethyl (meth) Methacrylate, and the like.
The polymerizable monomer having a crosslinkable functional group is preferably contained in an amount of 0.05 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1-12 carbon atoms . When the content is less than 0.05 part by weight, the cohesive force of the pressure-sensitive adhesive becomes small and durability may be deteriorated. When the content is more than 10 parts by weight, a high gel fraction may lower the adhesive strength and cause durability problems.
The acrylic copolymer may further contain other polymerizable monomers other than the above monomers in an amount not lowering the adhesive force, for example, 10% by weight or less based on the total amount.
The method for producing the copolymer is not particularly limited and can be produced by methods such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization, which are commonly used in the art, and solution polymerization is preferable. In addition, a solvent, a polymerization initiator, a chain transfer agent for molecular weight control and the like which are usually used in polymerization can be used.
The acrylic copolymer preferably has a weight average molecular weight (polystyrene conversion, Mw) of 50,000 to 2,000,000, more preferably 400,000 to 2,000,000 as measured by Gel Permeation Chromatography (GPC). When the weight-average molecular weight is less than 50,000, cohesion between co-polymers may be insufficient, which may cause problems in adhesion durability. If the weight average molecular weight is more than 2,000,000, a large amount of a diluting solvent may be required in order to ensure fairness in coating.
The antistatic agent used in the present invention essentially contains an iodine anion, thereby making it possible to exhibit excellent optical characteristics and durability even under severe conditions of high temperature and high humidity.
More specifically, under the conditions of high temperature and high humidity, the degree of freedom of the iodine anion is increased inside the polarizer, so that an anion exchange reaction easily occurs between the polarizer and the pressure-sensitive adhesive layer. The present invention includes an iodine anion in the pressure- The concentration of the iodide ion of the polarizer is not lowered, and excellent optical characteristics can be maintained.
The cation of the antistatic agent used in the present invention may be an organic cation.
The organic cation may contain three or more alkyl groups having 3 to 20 carbon atoms in the molecule. In this case, the volume occupied by the cations in the composition is increased so that the degree of freedom of the anion in the ion- It is judged that it is possible to inhibit the movement of the dense structure to the polarizer composed of the crosslinked polyvinyl alcohol resin.
Specific examples of the antistatic agent according to the present invention may be at least one compound selected from the compounds represented by the following formulas (1) to (3), but the present invention is not limited thereto. In view of reducing the degree of freedom of ions depending on the volume, 1 is preferably used.
[Chemical Formula 1]
(2)
(3)
In the above formulas, X is a sulfur atom, a nitrogen atom or a phosphorus atom, R 1 , R 2 , R 3 , R 1 'and R 2 ' are each independently an alkyl group having 3 to 20 carbon atoms, and when X is a sulfur atom , R 4 is, if non-covalent electron pair, and, X is a nitrogen atom or a phosphorus atom, R 4 is a hydrogen atom or a C 1 alkyl group of 1 to 20, R 3 'and R 4' each independently represent a hydrogen atom or a group having 1 to 20 carbon atoms Alkyl group.
More specific examples of the antistatic agent include the compounds represented by the following formulas (4) to (8).
[Chemical Formula 4]
[Chemical Formula 5]
[Chemical Formula 6]
(7)
[Chemical Formula 8]
The content of the antistatic agent is not particularly limited as long as it is within the range of its function. For example, the content of the antistatic agent may be 0.1 to 3 parts by weight, preferably 0.5 to 1 part by weight, based on 100 parts by weight of the acrylic copolymer. When the above range is satisfied, excellent antistatic properties are exhibited, and the release of iodine ions from the polarizer is effectively suppressed, whereby the optical characteristics and durability of the polarizer can be remarkably improved. If it is contained in an amount of less than 0.1 part by weight, it is difficult to exhibit its effect in a very small amount, and when it exceeds 3 parts by weight, adhesion durability due to bleeding out of an antistatic agent from a pressure- do.
The pressure-sensitive adhesive composition of the present invention may further comprise a crosslinking agent.
The crosslinking agent is a component for reinforcing the cohesive force of the pressure-sensitive adhesive by properly crosslinking the copolymer, and the kind thereof is not particularly limited. Examples thereof include isocyanate compounds and epoxy compounds, which may be used alone or in combination of two or more.
Examples of the isocyanate compound include tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate , Diisocyanate compounds such as naphthalene diisocyanate; An adduct obtained by reacting 3 moles of a diisocyanate compound with 1 mole of a polyhydric alcohol compound such as trimethylolpropane, an isocyanurate compound in which 3 moles of a diisocyanate compound is self-condensed, a diisocyanate obtained from 2 moles of 3 moles of a diisocyanate compound And multifunctional isocyanate compounds containing three functional groups such as burette, triphenylmethane triisocyanate and methylene bistriisocyanate in which the remaining one mole of diisocyanate is condensed in urea.
Examples of the epoxy compound include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol Hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, glycerol diglycidyl ether, glycerol diglycidyl ether, Diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcinol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, trimethylol propane triglycidyl ether, pentaerythritol Polyglycidyl ether, sorbitol polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, tris (glycidyl) isocyanurate N, N ', N'-tetraglycidyl-m-glycidoxyethyl isocyanurate, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, Xylylenediamine, and the like.
In addition, an isocyanate compound, an epoxy compound, and a melamine compound may be used alone or in admixture of two or more. Examples of the melamine-based compound include hexamethylol melamine, hexamethoxymethyl melamine, and hexabutoxymethyl melamine.
The crosslinking agent is preferably contained in an amount of 0.1 to 15 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the copolymer based on the solid content. When the content is less than 0.1 parts by weight, the cohesive force becomes small due to insufficient crosslinking, resulting in deterioration of durability and deterioration of cutability. If the content is more than 15 parts by weight, excessive crosslinking reaction may cause a problem of relaxation of residual stress.
The pressure-sensitive adhesive composition of the present invention may further comprise a silane coupling agent.
The silane coupling agent is added in order to improve the adhesion between the pressure-sensitive adhesive and the glass substrate. The type of the silane coupling agent is not particularly limited as long as it is within a functional range. Examples of the silane coupling agent include amino group, epoxy group, acetoacetyl group, polyalkylene glycol group, An alkoxysilane containing a functional group such as an acryl group or an alkyl group can be used.
The content of the silane coupling agent is not particularly limited, but is preferably 0.1 to 2.0 parts by weight, more preferably 0.1 to 0.5 parts by weight based on 100 parts by weight of the copolymer based on the solid content. If the content is less than 0.1 parts by weight, peeling may easily occur under the conditions of moist heat resistance, and if it is more than 2 parts by weight, peeling may occur under heat-resistant conditions.
The pressure-sensitive adhesive composition of the present invention may further contain additives such as a tackifier resin, an antioxidant, a leveling agent, a surface lubricant, a dye, a pigment, a defoaming agent, Fillers, light stabilizers, and the like.
The pressure-sensitive adhesive composition comprising the above-described components is applied to the other surface of the surface to which the protective film of the polarizer is bonded to form a pressure-sensitive adhesive layer.
The coating method is not particularly limited as long as it is a method commonly used in the art. For example, the surface of the surface of the protective film of the polarizer bonded by the Meyer bar coating method, the gravure coating method, the die coating method, the dip coating method, And a method of coating on the other surface.
The thickness of the pressure-sensitive adhesive layer formed by the above method is not particularly limited, and may be, for example, 3 to 100 탆, and preferably 10 to 100 탆.
<Image Display Device>
The present invention also provides an image display apparatus including the ultra-thin polarizer.
The image display apparatus of the present invention may further include a configuration known in the art in addition to the ultra-thin polarizing plate.
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.
Synthetic example : Acrylic copolymer
86 parts by weight of n-butyl acrylate (BA), 7 parts by weight of methyl acrylate (MA), 2 parts by weight of 2-hydroxyethyl acrylate (2.0 parts by weight) , 5 parts by weight of acrylic acid, and 80 parts by weight of ethyl acetate as a solvent. Nitrogen gas was then purged for 1 hour to remove oxygen and then maintained at 62 ° C. After the mixture was homogenized, 0.07 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator and reacted for 6 hours to prepare a copolymer (A) having a weight average molecular weight of at least 1.5 million.
Manufacturing example 1: Preparation of pressure-sensitive adhesive composition
The ingredients listed in Table 1 were mixed in the above amounts and then diluted with methyl ethyl ketone for coating properties to prepare a pressure-sensitive adhesive composition.
B-1:
B-2:
B-3:
B-4:
B-5:
B-6:
B-8:
B-9:
B-10:
B-11:
B-12:
C: Coronate L (COR-L, manufactured by Nippon Polyurethane Industry Co., Ltd.)
D: KBM-403 (Shin-Etsu)
Example And Comparative Example
Example One
< Polarizer Manufacturing>
A polyvinyl alcohol resin film having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more and having a thickness of 75 탆 was immersed in pure water at 30 캜 for 2 minutes while stretching it to about 1.5 times. Thereafter, the film was stretched to about 2.0 times while immersed in a dyeing bath containing an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.01 / 1.0 / 100 and a temperature of 30 ° C for 3 minutes. Thereafter, it was stretched to about 2.0 times while immersing in an aqueous solution of potassium iodide / boric acid / water mixed at a weight ratio of 10/5/100 at 53 캜 for 1 minute. Thereafter, the film was washed with pure water at 15 DEG C for 1.5 seconds and then dried at 50 DEG C for 5 minutes to prepare a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol.
≪ Preparation of adhesive >
3 parts by weight of an acetoacetyl group-modified polyvinyl alcohol resin (Kosenol Z200, Nippon Synthetic Chemical Industry Co., Ltd.) and 0.3 parts by weight of a glyoxal crosslinking agent (SPM-01, Nippon Gosei Co., Ltd.) were added to 100 parts by weight of water, 50 parts by weight of copper sulfate was added to 100 parts by weight of the above adhesive composition to prepare an adhesive layer forming composition.
≪ Production of polarizing plate &
The prepared adhesive layer-forming composition was coated on one surface of the polarizer so that the dry film thickness was 0.1 m, and then the saponified acetylcellulose-based film (30 cm x 20 cm) was bonded. The bonded body was dried at a temperature of 60 캜 for 3 minutes to prepare a polarizing plate.
≪ Preparation of Polarizer with Adhesive >
The pressure-sensitive adhesive composition prepared according to Preparation Example 1 was coated on the other surface of the polarizer having the protective film so that the thickness after drying was 25 占 퐉 and dried at 100 占 폚 for 1 minute to form an adhesive layer to prepare an ultra-thin polarizing plate.
Example 2 to 7
An ultra-thin polarizing plate was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive compositions of Production Examples 2 to 7 were used instead of the pressure-sensitive adhesive composition of Production Example 1, respectively.
Comparative Example 1 to 7
An ultra-thin polarizing plate was produced in the same manner as in Example 1, except that the pressure-sensitive adhesive compositions of Production Examples 8 to 14 were used instead of the pressure-sensitive adhesive composition of Production Example 1, respectively.
Test Methods
1. Heat resistance durability evaluation
The pressure sensitive adhesive layer of the prepared ultra-thin polarizing plate was bonded to a Corning glass and autoclaved. After leaving at 80 캜 for 300 hours, bubbles and peeling were observed. The results are shown in Table 2 below.
<Evaluation Criteria>
◎: No bubbles or peeling at all
○: There are bubbles or peeling, but only in very small areas.
Δ: Bubbles or peeling were confirmed somewhat
X: Bubbles or peeling of 1 cm or more across the area are easily visible to the naked eye.
2. Antistatic property
The surface resistivity was measured, and the results are shown in Table 2 below.
<Evaluation Criteria>
⊚: The surface resistivity is less than 1 × 10 ^ 10
○: The surface resistivity is more than 1 × 10 ^ 10 and less than 5 × 10 ^ 10
?: The surface resistivity is more than 5X10 ^ 10 and less than 1X10 ^ 11
X: surface resistivity of 1X10 ^ 11 or more
3. Wet heat Optical durability evaluation
The pressure-sensitive adhesive layer of the prepared ultra-thin polarizing plate was bonded to a Corning glass and subjected to autoclave treatment. After left at 60 ° C and 90% for 300 hours, the degree of polarization was measured. The results are shown in Table 2 below.
<Evaluation Criteria>
⊚: a degree of polarization of 95% or more
○: The degree of polarization is less than 90% and 95% or more
?: The degree of polarization is less than 85% and 90% or more
X: Less than 85% of polarization
durability
Optical durability
Table 2 shows that the ultra-thin polarizer according to the present invention exhibits excellent antistatic properties and heat durability, as well as excellent optical durability because the iodide ion in the polarizer is not reduced even under the anti-wet heat conditions.
However, the antistatic property and optical durability of Example 7, which contained the antistatic agent in a somewhat excessive amount in the pressure-sensitive adhesive layer, were excellent, but it was confirmed that the durability in the heat-resistant condition was slightly lower than those in the other Examples.
It was confirmed that the polarizing plates of Comparative Examples 1 to 7 using the antistatic agent containing no iodine anion easily lost the iodine anions from the polarizer under the humid at room temperature condition and the optical durability was remarkably lowered.
Claims (5)
Wherein the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition comprising an acrylic copolymer and an antistatic agent containing an iodine anion.
[Chemical Formula 1]
(2)
(3)
(Wherein X is a sulfur atom, a nitrogen atom or a phosphorus atom,
R 1 , R 2 , R 3 , R 1 'and R 2 ' are each independently an alkyl group having 3 to 20 carbon atoms,
When X is a sulfur atom, R 4 is a non-bonded electron pair,
When X is a nitrogen atom or phosphorus atom, R 4 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms,
R 3 'and R 4 ' each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020140057665A KR20150130721A (en) | 2014-05-14 | 2014-05-14 | Ultra thin polarizing plate and image display device comprising the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020140057665A KR20150130721A (en) | 2014-05-14 | 2014-05-14 | Ultra thin polarizing plate and image display device comprising the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20150130721A true KR20150130721A (en) | 2015-11-24 |
Family
ID=54844967
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020140057665A KR20150130721A (en) | 2014-05-14 | 2014-05-14 | Ultra thin polarizing plate and image display device comprising the same |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR20150130721A (en) |
-
2014
- 2014-05-14 KR KR1020140057665A patent/KR20150130721A/en not_active Application Discontinuation
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