KR20160050887A - Surface protective film for optical film and polarizer comprising thereof - Google Patents

Surface protective film for optical film and polarizer comprising thereof Download PDF

Info

Publication number
KR20160050887A
KR20160050887A KR1020140150030A KR20140150030A KR20160050887A KR 20160050887 A KR20160050887 A KR 20160050887A KR 1020140150030 A KR1020140150030 A KR 1020140150030A KR 20140150030 A KR20140150030 A KR 20140150030A KR 20160050887 A KR20160050887 A KR 20160050887A
Authority
KR
South Korea
Prior art keywords
protective film
layer
surface protective
film
optical film
Prior art date
Application number
KR1020140150030A
Other languages
Korean (ko)
Inventor
최병운
김형욱
최영은
Original Assignee
동우 화인켐 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 동우 화인켐 주식회사 filed Critical 동우 화인켐 주식회사
Priority to KR1020140150030A priority Critical patent/KR20160050887A/en
Publication of KR20160050887A publication Critical patent/KR20160050887A/en

Links

Images

Classifications

    • 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
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • 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
    • 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
    • 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
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • 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 a surface protective film for an optical film capable of absorbing moisture and a polarizing plate having the same, and more particularly to a polarizing plate for absorbing moisture such as calcium alginate or polyacrylamide having an average particle diameter of 0.1 to 2.5 μm To a surface protective film for an optical film containing a water-soluble particle and a polarizing plate comprising the same.
The polarizer is a low-moisture-content polarizer having a water content of less than 3% by weight due to the water-absorbing particles. The polarizer is excellent in durability and moisture absorption and curl is not generated. In addition, coloring of the polarizer due to moisture is prevented, The validity period or the retention period can be increased.
Such a polarizing plate is also applicable to various flat panel displays, preferably LCD panels and OLED panels, and is particularly applicable to OLED panels having a small amount of iodine-stained polarizer.

Description

TECHNICAL FIELD [0001] The present invention relates to a surface protective film for an optical film and a polarizing plate comprising the same. BACKGROUND ART [0002]

The present invention relates to a surface protective film for optical films having good moisture resistance and durability and an effect of suppressing curling, and a low permeability high permeability polarizing plate comprising the same.

BACKGROUND ART A flat panel display such as a liquid crystal display (LCD) and an organic light emitting diode (OLED) is composed of a large number of optical films made of a synthetic resin or an optical resin plate, have.

Unpolarized light emitted from the light source of the flat panel display is incident on the liquid crystal cell only by the linearly polarized light through the polarizing plate, and the intensity of the transmitted light is adjusted according to the degree of rotation of the polarization axis of the incident light and gray scale representation between black and white is possible . That is, the polarizing plate is one of the key materials for visually confirming the image implemented in the flat panel display.

In the case of an OLED, one polarizing plate and a quarter wavelength retardation film are used for the purpose of preventing reflection to an external light source, although two polarizing plates are usually used in an LCD.

Specifically, the polarizing plate for OLED is composed of a polarizing plate and a quarter-wave plate. At this time, light incident from the outside becomes linearly polarized light through the linearly polarized light layer and is circularly polarized through the quarter-wave retardation layer. Polarized light and linearly polarized light, the polarized direction of the polarized light is changed, and the reflected light is prevented from transmitting through the polarizing plate composed of the linearly polarized light layer, thereby preventing reflection.

Although OLED panels do not require a polarizer when implementing colors by themselves, polarizers for OLEDs, preferably polarizers with high transmittance, are used for implementing black color and preventing reflection of external light, which is particularly required in low power OLED panels.

Currently, the transmittance of LCD polarizer is 42% and the transmittance of OLED polarizer is 44%, so OLED polarizer is less iodine than LCD polarizer. As a result, when evaluating the reliability of the polarizing plate, iodine breakdown or sublimation occurs more easily in the oven, and the destruction and sublimation cause the durability of the polarizing plate for OLED to be weak.

Various methods have been suggested for solving the durability problems such as color dropout and redness which are caused in the reliability evaluation due to the low iodine dyeing of such high permeability polarizer.

For example, Korean Patent Publication No. 2010-0087339 Specifically, it discloses that when the boron and iodine content in the polarizer and the moisture content in the polarizing plate satisfy a certain relational expression, the durability of the polarizing plate is improved and the color separation phenomenon does not occur in a high temperature and high humidity environment.

On the other hand, a polarizing plate is obtained by orienting a polymer chain in a stretching direction by stretching a polyvinyl alcohol (PVA) film, immersing it in iodine and a dichroic dye solution, and arranging iodine molecules and dye molecules side by side in the stretching direction.

The PVA film dyed with iodine and a dichroic substance acts as a polarizer, and the mechanical strength of the film itself is weak, and it tends to shrink in the direction of stretching shrinkage due to changes in temperature or humidity as the stretching process proceeds. Therefore, the structure of surface treatment-TAC-adhesive-PVA-adhesive-TAC-adhesive, in which a triacetate cellulose (TAC) film that protects the polarizer is bonded to the top, bottom or both sides of the polarizer is the most basic form.

The polarizing plate is provided with a coating treatment having characteristics such as hardness enhancement, anti-reflection, low reflection, surface protection, etc. on the surface of the TAC film or polarizer according to the required characteristics. In addition, a retardation compensation film that can exhibit optimum effects such as birefringence, dichroism, reflection, and brightness enhancement is further stacked.

The polarizer and the protective film are usually bonded using an aqueous adhesive agent. At this time, the polarizer and the protective film are bonded to each other in a state of containing a predetermined amount of water, and are then hot-dried and cooled at room temperature. In this process, as the moisture is removed, the polarizer and the polarizer protective film are shrunk and contracted again at the room temperature cooling process. Such contraction causes curling of the polarizing plate to be bent.

Further, the polarizing plate may have a phenomenon in which the constituent members of the side portion are lifted or peeled off under high temperature or high pressure conditions. In this case, water may easily flow into the inside of the polarizing plate from the outside in the handling process including transport and storage of the polarizing plate. The influxed water expands the polarizing plate and is dried according to changes in temperature and humidity in the post-process, thereby shrinking the polarizing plate and further exacerbating curl generation.

When the curled polarizing plate is bonded to the cell, bubble generation, lifting, or peeling may occur on the bonding surface, which may lower the bonding durability and cause problems of appearance defects. Such flat panel display devices are often used under high temperature or high temperature and high humidity conditions depending on a wide use. Therefore, the polarizing plate is required to have reliability (durability) that does not deteriorate optical characteristics even in a high temperature environment or a high temperature and high humidity environment.

In order to solve the problems caused by the moisture of the polarizing plate, Korean Patent Laid-Open Publication No. 2006-0119132 discloses that a coating layer is formed on the side surface of the polarizing plate laminate using a usual acryl, silicone, urethane or epoxy waterproofing liquid, thereby causing shrinkage and expansion of the polarizing plate, Thereby suppressing the occurrence of curl.

Korean Patent Laid-Open Publication No. 2013-0102451 discloses a protective film for moisture barrier property, mechanical strength, thermal stability, etc. formed on both sides of a polarizer, and a portion to which an adhesive used for suppressing curling, And control the curl by controlling the curl.

Korean Patent Laid-Open Publication No. 2008-0043699 discloses a method of controlling curl generated due to moisture by bonding TAC having different thicknesses and moisture contents to both sides of a polarizer.

These patents solve some of the problems of curl, but the effect is not sufficient and the problem of discoloration can not be solved yet. A new problem arises in that the thickness of the polarizer is increased by the addition of another layer.

Korean Patent Publication No. 2010-0087339 Korean Patent Publication No. 2006-0119132 Korean Patent Publication No. 2013-0102451 Korean Patent Publication No. 2008-0043699

As a result of various studies for producing a low-moisture-permeability polarizer having stable quality and high transmittance, a protective film for moisture absorption of a polarizing plate was produced, and a material for absorbing moisture in the protective film was used, As a result of the experiment, it was confirmed that a high-quality polarizing plate can be produced because no color separation phenomenon and no curling occurred, thereby completing the present invention.

Accordingly, an object of the present invention is to provide a surface protective film for an optical film, which can attach to a polarizing plate and absorb moisture in the polarizing plate, thereby realizing a low permeability high permeability polarizing plate.

Another object of the present invention is to provide a low-moisture-content polarizing plate having a protective film on a polarizing plate and having good moisture resistance and durability, a high transmittance, and suppressed curling.

In order to achieve the above object, the present invention provides a surface protective film for an optical film in which an adherent layer and a back surface layer are sequentially laminated,

Wherein the adhered layer includes one kind of water-absorbing particles selected from the group consisting of metal alginate, polyacrylamide, and combinations thereof.

The surface protective film for an optical film further includes an intermediate layer between the adhered layer and the back layer.

At this time, the water-absorbing particles may be included in at least one layer of the intermediate layer and the adhered layer.

The water-absorbing particles preferably have an average particle diameter of 0.1 to 2.5 占 퐉, preferably 0.5 to 2.0 占 퐉.

Such water-absorbing particles are contained in an amount of from 5 to 40% by weight, preferably from 10 to 30% by weight, of the entire deposited layer composition.

The present invention also relates to an optical film comprising an upper and a lower protective film; And a polarizer interposed therebetween, wherein the protective film of any one of the upper and lower protective films is a surface protective film for an optical film as described above.

Wherein the polarizer is a low permeability high permeability polarizer having a water content of less than 3% by weight.

The surface protective film for an optical film proposed in the present invention is attached to one side of a polarizing plate, thereby realizing a low permeability high permeability, high durability polarizing plate.

The polarizing plate is excellent in durability and moisture resistance and not only does not cause curling, but also can prevent the color of the polarizer from dropping due to the conventional moisture, thereby increasing the shelf life or storage period of the polarizing plate without deteriorating quality.

Such a polarizing plate is also applicable to various flat panel displays, preferably LCD panels and OLED panels, and is particularly applicable to OLED panels having a small amount of iodine-stained polarizer.

1 is a cross-sectional view showing a surface protective film for an optical film according to a first embodiment of the present invention.
2 is a cross-sectional view showing a surface protective film for an optical film according to a second embodiment of the present invention.
3 is a cross-sectional view showing a surface protective film for an optical film according to a third embodiment of the present invention.
4 is a cross-sectional view illustrating a surface protective film for an optical film according to a fourth embodiment of the present invention.
5 is a cross-sectional view illustrating a surface protective film for an optical film according to a fifth embodiment of the present invention.
6 is a cross-sectional view showing a surface protective film for an optical film according to a sixth embodiment of the present invention.
7 is a cross-sectional view illustrating a surface protective film for an optical film according to a seventh embodiment of the present invention.
8 is a cross-sectional view illustrating a surface protective film for an optical film according to an eighth embodiment of the present invention.
FIG. 9 is a graph showing a change in moisture content of a protective film according to the content of calcium alginate prepared in Production Example 1. FIG.
10 is a view showing a reliability evaluation result of a polarizing plate into which a surface protective film for an optical film is introduced.

The surface protective film for an optical film according to the present invention is attached to a polarizing plate to protect the polarizing plate, removes water present in the polarizing plate, realizes a low permeability high permeability polarizing plate, And before the polarizing plate is bonded.

Such a surface protective film for optical film is a 'moisture-absorbing protective film' having a structure in which a layer for absorbing moisture and a layer for protecting a polarizing plate from the outside are laminated, and is a multilayer film of at least two layers or more.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 is a cross-sectional view showing a surface protective film for an optical film according to a first embodiment of the present invention.

The protective film of Fig. 1 is composed of an adhered layer 1 and a back layer 3.

The adhesive layer (1) of the present invention is a layer which is in contact with another film in a protective film and must have a tackiness which is easy to adhere and peel off, and is also referred to as an adhesive layer. This adhered layer 1 is a surface directly contacting the polarizing plate, and water-absorbing particles are used in the present invention in order to prevent quality deterioration such as color separation of the polarizing plate due to moisture.

The 'water-absorbing particle' referred to in the present specification means a polymer material having a function of absorbing moisture and having a spherical particle shape.

These polymeric materials have the property of 'hydrogel', and the polymer is partially connected to each other by bonds of certain specific sites in the chain (eg, hydrogen bonds) to form a three-dimensional network structure. At this time, upon contact with moisture, hydration occurs in which moisture is absorbed in the network structure, swelling occurs, and the translucent water-absorbing particles are changed transparently by the swelling. This absorption process is an irreversible process, and once absorbed moisture is not dehydrated unless there is an additional process.

This feature can have several effects.

First, in the case of a surface protective film for an optical film, the transparency must be maintained to a certain degree, and transparency is increased when the water-absorbing particle absorbs moisture, so that the above requirements can be met.

Secondly, the shape (e.g., porosity) of the polymer material can be easily controlled so that the particle size can be easily controlled and a high specific surface area can be secured.

Thirdly, the swelling rate can be easily controlled by controlling not only the material, particle size, and shape but also the amount of the used material, and the degree of moisture absorption can be easily controlled when applied to a low-moisture polarizing plate.

Fourthly, when the surface protective film for an optical film including the water-absorbing particles is bonded to the polarizing plate, moisture present in the polarizing plate or absorbed by the polarizing plate from the outside can be effectively absorbed, and moisture is transferred to the polarizing plate The dehydration does not occur.

Preferably, the material of the water-absorbing particles includes one selected from the group consisting of metal alginate, polyacrylamide, and combinations thereof, and they may be used individually or in combination.

In the mixed use, metal alginate and polyacrylamide can be used in a weight ratio of 1: 0.1 to 1:10, and water absorption effect and transparency can be further secured through such mixing use.

The metal alginate may be a divalent alkali metal alginate selected from the group consisting of calcium alginate, barium alginate, strontium alginate, and combinations thereof, preferably calcium alginate. These divalent alkali metal alginates are superior to the monovalent sodium alginate in water absorption ability.

The water content and the swelling rate of the calcium alginate particles after preparation of the calcium alginate particles were measured in Production Example 1 of the present invention. As a result, it was confirmed that the calcium alginate particles were able to absorb moisture effectively. Due to these water-absorbing particles, it is possible to effectively absorb the moisture present in the polarizing plate or in the surrounding environment, that is, from the outside, thereby effectively preventing the problem of discoloration or curling of the polarizer.

At this time, a known hydrogel polymer may be further added to the water-absorbing particles. The hydrogel polymer is a polymer structure having a three-dimensional network structure containing an aqueous phase. The hydrogel polymer is composed of a hydrophilic polymer, which is freezing and thawing, crystallization, radiation, hydrogen bonding interaction Physical crosslinking such as chemical crosslinking, chargeinteraction, hydrophobic interaction, stereocomplexation, or the like, or chemical crosslinking through covalent bonding using a crosslinking agent it means. The hydrogel polymer usable in the present invention is not particularly limited, and any known hydrogel polymer may be used.

Typically, hydrogel polymers can be largely divided into natural polymers and synthetic polymers, which preferably have hydrophilic functional groups such as OH, COOH, NH 2 , and sulfonic acids in the molecular structure.

Examples of natural polymers include modified alginate, chitosan, cyclodextrin, hyaluronic acid, agarose, starch, carraquinone, gum arabic, xanthan gum, carboxymethylcellulose, gelatin, pectin, collagen, fibrin, and combinations thereof And the like.

Examples of the synthetic polymer include modified polyacrylamide, polyvinyl alcohol, polyvinyl acetate, poly (C2 to C3) alkylene glycol, poly (C2 to C3) alkylene oxide, polyhydroxybutyrate, polystyrene, polyvinylpyrrolidone, One kind selected from the group consisting of polyacrylic acid, polymaleic acid, polyglycolic acid, polylactic acid, polycaprolactone, and copolymers thereof.

In addition, the natural and synthetic polymers may be used individually or in combination, and other hydrophilic substances such as polypeptides may be introduced, if necessary.

More specifically, the combinable hydrogel polymer is selected from the group consisting of polyvinyl alcohol-polyvinylpyrrolidone (PVA-PVP), polyethylene glycol-polyvinyl alcohol (PEG-PVA), polyvinyl alcohol-polyacrylic acid (PVA- (PEO-PLA), polyethylene glycol-polylactic acid (PEG-PLA), polyethyleneglycol-poly (vinyl alcohol), polyvinyl alcohol-polyvinylacetate (PEG-PCA), polyethylene glycol-polylactic acid-polyethylene glycol (PEG-PLA-PEG), polyethylene glycol-poly (lacto- co- glycolic acid) -polyethylene glycol (PEG- polycaprolactone-polyethylene glycol (PEG-PCL-PEG), polylactic acid-polyethylene glycol-polylactic acid (PLA-PEG-PLA), poly (polyethylene glycol-co-peptides) (P (PEG- co -peptide) ) , Polyethylene glycol-polybutylene oxide (PEG-PBO), poly Ethylene glycol-poly (ε- caprolactone-co-lactide) (PEG-PCLA), polyethylene glycol-bis- (polyacrylic acid-acrylate) (PEG-bis- (PLA- acrylate)), polyacrylamide-polystyrene (PAAm-PS), poly-acrylamide-polymaleic acid (PMA-PAAm), polyacrylamide-polyacrylic acid (PAA-PAAm), poly (acrylic acid -co--hydroxyethyl methacrylate) (P (AA- co (HEMA)), poly (methyl methacrylate-co-hydroxyethyl methacrylate) (P (MMA- co- HEMA)), polyacrylic acid-carboxymethyl chitosan (PAA-CMC), collagen- - g-poly (sodium acrylate), polyacrylamide / sodium alginate, cellulose-alginate, alginate-g - (PEO-PPO-PEO), alginate-g - (polyethylene oxide-polypropylene oxide-polyethylene oxide)), Poly (lactone- co -aryl sulfonic acid sodium)), poly (polylactic- co -glycolic acid- co -serine) ).

Such water-absorbing particles are spherical particles having an average particle diameter of 0.1 to 2.5 占 퐉, preferably 0.5 to 2.0 占 퐉. If the average particle size of the water-absorbing particles is too small, coagulation will occur to each other, which can not achieve uniform dispersion in the adhesive layer 1, or an excessive amount must be used for moisture absorption. There is a risk of degradation. On the contrary, when the particles are too large, cracks may occur during dispersion in the adhered layer 1, which may cause breakage. In addition, there is a possibility that the transparency of the surface protective film for an optical film is lowered. Use it properly.

As described above, the content of the water-absorbing particles whose particle size is controlled is controlled so as to exhibit a sufficient level of moisture absorption within a range not lowering the transparency.

Preferably, the water-absorbing particles may be used in an amount of 5 to 40% by weight, preferably 10 to 30% by weight, based on 100% by weight of the composition constituting the entire adhered layer (1). If the content is less than the above range, it is difficult to secure a sufficient water absorption effect, and problems such as occurrence of curling and discoloration of polarizer are difficult to be solved and durability is lowered, Which makes it difficult to produce such a product. On the other hand, when the amount is in excess of the above range, the moisture resistance can be improved, but not only the transparency of the surface protective film for optical film is lowered, but also the adhesive property or adhesion ability to the polarizing plate It may be deteriorated. Therefore, it is suitably used within the above range.

In addition to the above-mentioned water-absorbing particles, the adhesive layer 1 has properties of a heatable adherent layer or a pressure-sensitive adhesive layer and includes a tacky composition for adhesion to a polarizing plate. Such a composition is not only adhesive, but also transparency, Composition and content are controlled in consideration of physical properties such as tensile strength as a film.

Preferably, the adhered layer (1) comprises a low-density polyethylene, a styrene-based elastomer, and a polyurethane together with the water-absorbing particles.

Polyethylene is different in properties depending on the polymerization method and is distinguished by density difference. The low density polyethylene has a density in the range of 0.910 to 0.925 g / cm < 3 >, which is smaller in hardness than the high density polyethylene having a density in the range of 0.941 to 0.965 g / cm3, but has excellent elongation and cold resistance. Used to provide.

The low density polyethylene is used in an amount of 30 to 90% by weight, preferably 40 to 80% by weight, within 100% by weight of the total adhesion layer (1) composition. If the content is less than the above range, the transparency, strength and hardness of the adhered layer 1 are lowered to cause a problem with the quality of the entire protective film. On the contrary, if the content exceeds the above range, It is preferable to use them appropriately within the above range.

The styrene-based elastomer, which is another constituent of the adhered layer (1), imparts tackiness in the protective film so as to be adhered well to other films. So that it has properties of a heat-sensitive adhesive layer or a pressure-sensitive adhesive layer.

Such styrene-based elastomers include block copolymers of styrene-based polymer block and olefin-based polymer block, block copolymer of styrene-based polymer block and styrene-based monomer and olefin-based monomer, or random copolymer of styrene and olefin , And at least one styrene-based elastomer selected from the hydrogenated products thereof are preferably used. When the styrene-based elastomer has an unsaturated double bond derived from an olefin, it is preferable that the unsaturated double bond is hydrogenated if necessary in view of enhancing heat resistance.

Among these, a block copolymer of a random copolymer block of a styrene polymer block, a styrene monomer and an olefin monomer, or a random copolymer of styrene and an olefin is preferable, and a styrene content of 5 to 30 wt% and a butadiene content 95 to 70% by weight is preferable.

Such a styrene-based elastomer has a weight average molecular weight of 100,000 to 600,000, and more preferably 200,000 to 500,000.

Preferably, the styrene elastomer according to the present invention is at least one selected from the group consisting of SIBS (styrene-isoprene-butadiene-styrene block copolymer), SBS (styrene-butadiene-styrene block copolymer), SIS (styrene-isoprene-styrene block copolymer) , SEBS (styrene-ethylene-butylene-styrene block copolymer), SEPS (styrene-ethylene-propylene-styrene block copolymer) Butadiene copolymer), SBPS (styrene-ethylene-propylene-styrene copolymer), and a combination thereof. Preferably, SBC is used.

The styrene-based elastomer comprises 5 to 40% by weight, preferably 10 to 30% by weight, based on 100% by weight of the total adhesion layer (1) composition. If the amount of the styrene-based elastomer exceeds the range, the tackiness is insufficient. On the contrary, if the content is low, the cohesive force is decreased and the adherend is contaminated at the time of peeling.

The polyurethane is used to improve the adhesion and adhesion of the adhered layer 1 so that the surface protective film for an optical film can be adhered well to the polarizing plate without a separate adhesive layer. The polyurethane has high wettability and can increase the adhesion of the polarizer to the film. For example, the polyurethane film can be used when the film of the polarizer to be attached has high non-tackiness (e.g., PET material).

The polyurethane proposed in the present invention is preferably formed by the reaction of a polyol and an isocyanate. At this time, the polyol may be a polyester polyol, a polyether polyol, a polycarbonate diol, or the like.

The polyester polyol is typically obtained by reacting a polybasic acid component with a polyol component. The polybasic acid component may be, for example, ortho-phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalene dicarboxylic acid, 2,5-naphthalene dicarboxylic acid, 2,6- Aromatic dicarboxylic acids such as acid, biphenyldicarboxylic acid, and tetrahydrophthalic acid; Aliphatic dicarboxylic acids such as oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, linoleic acid, maleic acid, fumaric acid, mesaconic acid and itaconic acid; Alicyclic dicarboxylic acids such as hexahydrophthalic acid, tetrahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; Or reactive derivatives thereof such as acid anhydrides, alkyl esters, and acid halides, and these may be used alone or in combination of two or more.

The polyol component is not particularly limited as long as it has two or more hydroxy groups in the molecule, and any suitable polyol may be employed. For example, the polyol may be at least one selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, Diethylene glycol, triethylene glycol, polyethylene glycol (PEG), diethylene glycol, triethylene glycol, triethylene glycol, triethylene glycol, , Dipropylene glycol, polytetramethylene glycol (PTMG), polypropylene glycol (PPG), 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, bisphenol A, bisphenol F, glycerin, -Trimethylolpropane, 1,2,5-hexatriol, pentaerythritol, glucose, sucrose, and sorbitol.

Further, the polyether polyol is typically obtained by ring-opening polymerization of an alkylene oxide to a polyhydric alcohol. As the polyhydric alcohol, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, etc. may be used alone or in combination of two or more.

Further, the polycarbonate polyol may be at least one or more selected from the group consisting of, for example, poly (hexamethylene carbonate) glycol and poly (cyclohexanecarbonate) glycol.

On the other hand, the isocyanate compound is not limited as long as it is a compound having two or more NCO groups, and examples thereof include toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5- (XDI), such as tolylene diisocyanate (TODI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), p-phenylenediisocyanate, transcyclohexane, 1,4-diisocyanate and xylene diisocyanate May be used alone or in combination of two or more.

In the present invention, the polyurethane may be used in an amount of 0 to 15% by weight, preferably 1 to 10% by weight, in the entire adhesion layer (1) composition. If the content exceeds the above range, the residue of the adhered layer (1) composition may cause contamination of the polarizing plate during desorption of the surface protective film for optical film in the polarizing plate due to high adhesive force, Use it properly.

The composition of the adhered layer (1) may further include a known tackifier in addition to the above composition. Examples of such a tackifier include polyterpenes having a glass transition temperature (Tg) of 30 to 100 캜 and a softening temperature of 30 to 150 캜. As the structural units of the polyterpene, there are α-pinene, β-pinene and dipentene, and also hydrogenated products (hydrogenated terpene resins). Modified materials include terpene styrene resin and terpene phenol resin. Examples of the rosin include rosin, polymerized rosin, hydrogenated rosin, rosin-modified product, glycerin ester of rosin or hydrogenated rosin as a derivative, and pentaerythritol ester. Among them, a terpene phenol resin is preferable from the viewpoint of uniform mixing with a styrene-based elastomer.

On the other hand, the backing layer 3 located on the adhered layer 1 prevents the blocking phenomenon of the film sticking to each other upon winding, protects the polarizing plate from the outside, and prevents surface scratches. In order to prevent the blocking phenomenon (i.e., anti-blocking property), it has a slip property and has suitable strength, dimensional stability and transparency for protecting the polarizing plate.

The backing layer 3 is made of polypropylene, which is excellent in transparency, strength and dimensional stability, and an inorganic filler is used for imparting slipperiness and anti-blocking property thereto. Preferably, 90 to 95.5% by weight of polypropylene and 0.05 to 10% by weight of an inorganic filler are included in the total backing layer 3 composition.

The polypropylene may be a homopolymer of a propylene monomer or a copolymer of an alpha -olefin monomer, and may preferably be a polypropylene homopolymer for high strength. The α-olefin may be selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, Sen, and a combination thereof.

Such polypropylene is not limited in its structure and includes both isotactic, syndiotactic and atactic structures.

As described above, the inorganic filler increases the degree of roughness of the surface of the backing layer (3), thereby facilitating slip between the films during winding, improving the anti-blocking property to improve the winding property, and significantly improving the defective rate of the film after winding For use.

Such an inorganic filler is not specifically mentioned in the present invention, and known inorganic particles may be used. Typical examples include silica, calcium carbonate, magnesium carbonate, titanium dioxide, clay, talc, magnesium hydroxide, aluminum hydroxide, zeolite, zirconia, antimony oxide and zinc oxide.

However, when the inorganic filler is present in the back layer 3, the particle size and the content of the inorganic filler are controlled within a range that does not cause a decrease in the physical properties of the film while sufficiently exhibiting slip property.

Preferably, the inorganic filler has an average particle size of 1 to 10 탆, preferably 1 to 5 탆, and the content thereof is 0.05 to 10% by weight, preferably 0.1 to 5% It is used in weight%.

If the particle size is less than the above range, uniform dispersion can not be achieved throughout the backing layer 3 due to lumps of the particles in the film forming process, and conversely, if the particle size is used in excess of the above range, The transparency of the surface protective film for the entire optical film is largely lowered due to the opacity peculiar to silica and the particles may become a crack point in the film and cause breakage.

If the content is less than the above range, the slipping property of the backing layer 3 is not sufficient and blocking phenomenon occurs in which the films adhere to each other at the time of winding into a roll. On the other hand, if the content exceeds the above range, And the particle may become a crack point in the film and cause breakage. Therefore, it is suitably used within the above-mentioned range.

At this time, the back layer 3 may further include other compositions to improve slip properties for various purposes, for example, to more effectively prevent blocking during winding, to improve mechanical properties and optical characteristics, and to improve workability.

Preferably, the propylene /? - olefin copolymer is contained in an amount of 40 wt% or less, more preferably 10 to 40 wt%, low-density polyethylene 20 wt% or less, more preferably 1 to 20 wt% 10% by weight or less, more preferably 0.5 to 10% by weight, of the fluorine compound.

The propylene -? - olefin copolymer may be a random or block copolymer in which propylene and an? -Olefin are copolymerized, and preferably a propylene-ethylene random copolymer, as mentioned in the above-mentioned layer (1). Such a propylene -? - olefin copolymer has elasticity and can improve not only the flexibility of the film but also the processability, heat resistance and flexibility of the film.

At this time, the flexibility of the copolymer increases as the content of? -Olefin is increased, but the melting point of the copolymer is lowered to lower the processability. On the contrary, when the content is lower, the heat resistance is improved. , And the content of? -Olefin in the copolymer is preferably 3 to 7% by weight.

The low-density polyethylene follows the content mentioned in the above-mentioned deposited layer (1) and is used for increasing the strength or flexibility of the film.

The fluorine compound is characterized by having a polyfluorohydrocarbon group or a polyfluoro hydrocarbon group containing an etheric oxygen atom. The back layer preferably comprises a propylene resin containing 0.5 to 10% by weight of a fluorine-containing compound containing a polyfluoro-hydrocarbon group and a polyoxyethylene group at the same time. However, the polyfluoro-hydrocarbon group and polyoxyethylene Examples of the fluorine-containing compound include (meth) acrylic esters having a perfluoroalkyl group having 1 to 18 carbon atoms as the monomer (a), and examples of the monomer (b) and the monomer (c) (Meth) acrylic acid ester having an ethylene group and the like.

The perfluoroalkyl group of the monomer (a) preferably has 1 to 18 carbon atoms, more preferably 1 to 6 carbon atoms. Such a perfluoroalkyl group may be either linear or branched. These may be used alone or in combination of two or more.

Such a (meth) acrylic acid ester having a perfluoroalkyl group is commercially available from Kyoeisha Kagaku Co., Ltd., or can be synthesized by a known method using a commercially available fluorine-containing compound as a raw material.

As the monomer (b) containing a polyoxyethylene group, it is preferable that it has a structure in which 1 to 30 oxyethylene units (-CH 2 -CH 2 -O-) are cascade, more preferably 1 to 20 units . In addition, an oxypropylene unit (-CH 2 -CH (CH 3 ) -O-) may be contained in the chain. As a preferable example, polyethylene glycol monomethacrylate having 8 oxyethylene units can be exemplified. The monomers (b) may be used singly or in combination of two or more.

As another monomers (c) containing another polyoxyethylene group, di (meth) acrylate having a structure in which an oxyethylene unit is 1 to 30 contiguous chains and having a double bond at both terminal ends, Polyethylene glycol dimethacrylate having a number average molecular weight of 8, and the like. These monomers (c) may be used singly or in combination of two or more.

The ratio of the monomer (a), the monomer (b) and the monomer (c) is 1 to 80% by weight, the monomer (b) is 1 to 80% by weight, the monomer (c) %.

The fluorine-containing compound having a polyfluoro hydrocarbon group and a polyoxyethylene group may be copolymerized with monomers capable of copolymerizing the above three monomers in a range of less than 50% by weight. Examples of such a monomer include methylene, vinyl acetate, vinyl chloride, vinyl fluoride, vinyl halide, styrene, methylstyrene, (meth) acrylic acid and its ester, (meth) acrylamide monomer and (meth) allyl monomer.

The polymerization method for obtaining a fluorine-containing compound having a polyfluoro hydrocarbon group and a polyoxyethylene group by using the monomer may be any of bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization. In addition to thermal polymerization, Polymerization may also be employed.

As described above, the protective film for an optical film according to the first embodiment of the present invention has a two-layer structure of an adhering layer 1 and a backing layer 3, and the adhered layer 1 has a water absorbing ability The back layer 3 contains an inorganic filler as an active ingredient in order to impart slipperiness.

At this time, each layer may further contain known additives for various purposes, and the content of the additives is preferably 5 wt% or less in each layer composition. These additives may be lubricants, antioxidants, ultraviolet absorbers, pigments, antistatic agents, nucleating agents, heat stabilizers, UV absorbers, flame retardants and the like.

The thicknesses of the adhering layer 1 and the backing layer 3 according to the present invention have sufficient physical properties to be applied as a protective film of a polarizing plate and have a sufficient range of securing sufficient effects according to the purpose of each layer and the intended use .

Such a two-layer surface protective film for optical films is manufactured by adjusting the thickness of each layer so that it can be applied as a surface protective film of a polarizing plate having appropriate physical properties. Preferably, the deposited layer 1 is 15 to 50% of the total thickness and the intermediate layer 5 is 50 to 85%. Specifically, the thickness of the adhesive layer 1 is 3 to 50 탆, and the thickness of the back layer 3 is 2 to 50 탆. From the viewpoints of moldability and ease of use, the surface protective film for an optical film having a two- Mu] m to 100 [mu] m, preferably 20 to 100 [mu] m.

At this time, if the thickness of the adhering layer 1 is too thin, the adhesive property and the water absorption effect of the film are not sufficient. On the contrary, if the thickness is too thick, peeling is difficult to be performed when the film is detached from the polarizing plate, or the polarizing plate may be contaminated upon peeling.

If the thickness of the backing layer 3 is less than the above range, not only the protection of the polarizing plate can be effectively performed but also prevention of blocking can be difficult. On the contrary, if the thickness is too large, .

On the other hand, the surface protective film for an optical film having the above structure may further include an intermediate layer 5 between the adhered layer 1 and the back layer 3.

2 is a cross-sectional view showing a surface protective film for an optical film according to a second embodiment of the present invention.

The surface protective film for an optical film of Fig. 2 is composed of an adhered layer 1, an intermediate layer 5 and a back layer 3. At this time, the adhered layer 1 and the back layer 3 are as described in the first embodiment.

The intermediate layer (5) of the present invention serves as a support for the adhering layer (1) and the back layer (3), and polypropylene excellent in transparency and strength is used.

The polypropylene may be a homopolymer of a propylene monomer or a copolymer of an? -Olefin and a propylene monomer. The thickness of the polypropylene is preferably 5 to 1000 μm, more preferably 10 to 500 μm, in view of the above physical properties. If the thickness exceeds the above range, the thickness of the surface protective film for the entire optical film becomes too thick, which may lower the windability.

In addition, the intermediate layer 5 may further include water-absorbing particles present in the adhered layer 1 if necessary. Such a water-absorbing particle has a water-absorbing effect as mentioned in the adhered layer (1), and is contained in the intermediate layer (5), thereby blocking moisture from the outside and absorbing moisture present in the polarizing plate more effectively .

The water-absorbing particles contained in the intermediate layer 5 may be used in an amount of 5 to 40% by weight, preferably 10 to 30% by weight, in the whole intermediate layer 5 composition. At this time, the content range is limited to that mentioned in the deposited layer (1) of the first embodiment.

The surface protective film for an optical film according to the second embodiment of the present invention has a three-layer structure of an adhered layer 1, an intermediate layer 5 and a back layer 3, and the adhered layer 1 and / The intermediate layer (5) contains water-absorbing particles for imparting water absorbing ability and the back layer (3) contains an inorganic filler as an active ingredient for imparting slip property. At this time, the water-absorbing particles should be present at a certain level in the surface protective film for the entire optical film, and if they are present in each of the adhered layer (1), the intermediate layer (5) do. Further, when the water-absorbing particles are present in the back layer 3, blocking occurs more seriously during winding.

Such a three-layered surface protective film for an optical film is manufactured by adjusting the thickness of each layer so that it can be applied as a surface protective film of a polarizing plate having appropriate physical properties. Preferably, the deposited layer 1 is 10 to 30% of the total thickness, the intermediate layer 5 is 50 to 80%, and the back layer 3 is 5 to 20%. Specifically, the thickness of the adhering layer 1 is 3 to 20 占 퐉, the thickness of the intermediate layer 5 is 10 to 100 占 퐉, and the thickness of the backing layer 3 is 2 to 10 占 퐉. In view of moldability and ease of use, It is preferable that the surface protective film for the optical film of layer structure has a thickness of 15 to 130 탆, preferably 20 to 100 탆.

In the surface protective film for an optical film according to the first and second embodiments described above, the water absorbing particles are contained in the adhered layer and / or the intermediate layer to effectively block moisture introduced from the outside. At this time, the swelling rate varies depending on the material of the water-absorbing particles, but the moisture content is 50% by weight or more, and water can be effectively absorbed by about 10 to 50% of the weight of the water-absorbing particles. As a result, it becomes possible to manufacture a low-water-content polarizing plate by efficiently absorbing water that flows into the polarizing plate from the outside when the polarizing plate is attached to the polarizing plate or can not be removed in the drying process.

The production of the surface protective film for optical films of two-layer and three-layer structure according to the first and second embodiments proposed in the present invention is not particularly limited in the present invention, and follows a known film processing process. For example, various methods such as a blade method, a gravure roll coating, a slit die coating, and a lamination method are possible, and a slit die coating method can be preferably used.

For example, the compositions constituting each layer are melt-extruded in individual extruders, laminated and integrated in a nip, and co-extruded in a so-called three-layer structure to form a laminate of the back layer, the intermediate layer and the adhesive layer, A method of producing a surface protective film is possible.

Further, a method of melt-extruding the back layer, the intermediate layer and the pressure-sensitive adhesive layer individually and then integrally laminating the pressure-sensitive adhesive layer on the back surface layer and / or the intermediate layer by a lamination method.

In the former, known methods such as the inflation method and the T-die method are used. In the latter method, the melt extrusion method or extrusion coating method using dry lamination or T-die can be used. The hot melt co-extrusion method by the T-die method is preferable in terms of quality and economy.

The surface protective film for an optical film according to the present invention is preferably applicable to a polarizing plate. Upper and lower protective films; And a polarizer interposed therebetween, wherein the surface protective film for an optical film can be used for one or both of an upper portion and a lower portion of the polarizer. The surface protective film for an optical film can also be introduced as a release film. The polarizer includes upper and lower protective films and a polarizer interposed therebetween. An anti-reflection (AR) layer, an anti-glare (AG) layer, a scratch- Various layers such as an adhesive layer, an adhesive layer, or a retardation layer can be laminated.

FIGS. 3 to 7 show that the surface protective film for an optical film is introduced into a polarizing plate and can be applied to any position of the polarizing plate.

3 shows a third embodiment of the present invention in which a lower protective film 101, a polarizer 103, an adhesive 105, a TAC 107 and an upper protective film 109 are stacked in this order, The protective film is applied to the lower protective film.

FIG. 4 is a sectional view of a lower protective film 101, a TAC 107, an adhesive 105, a polarizer 103, an adhesive 105, a TAC 107, and an upper protective film 109 in the fourth embodiment of the present invention And the surface protective film for the optical film is applied to the lower protective film.

5 shows a fifth embodiment of the present invention in which a lower protective film 101, a polarizer 103, an adhesive 105, a TAC 107 and an upper protective film 109 are stacked in this order, The protective film is applied to the upper protective film.

6 is a cross-sectional view showing a sixth embodiment of the present invention in which the lower protective film 101, the adhesive 111, the retardation film 113, the adhesive 111, the polarizer 103, the adhesive 105, the TAC 107, And a protective film 109 are laminated in this order, and the surface protective film for optical film is applied to the lower protective film as a release film.

7 is a cross-sectional view showing a seventh embodiment of the present invention in which a lower protective film 101, an adhesive 111, a retardation film 113, an adhesive 105, a polarizer 103, an adhesive 105, a TAC 107, And a protective film 109 are stacked in this order, and the surface protective film for optical film is applied to the upper protective film.

8 is a sectional view showing an eighth embodiment of the present invention in which a lower protective film 101, a polarizer 103, an adhesive 105, a TAC 107 and an upper protective film 109 are stacked in this order, The protective film is applied to the upper and lower protective films.

Particularly, the surface protective film for an optical film of the present invention can solve the problem of color separation and curl caused by moisture. The surface protective film for an optical film may adhere to a polarizing plate to absorb moisture and be removed before bonding with the liquid crystal panel or the OLED panel to obtain a low moisture content polarizer having a water content of less than 3% by weight, preferably 2 to 3% by weight.

The low-moisture-permeability polarizing plate is a high-quality polarizing plate that does not generate high durability, moisture resistance, color separation and curling. As described above, by using the protective film as described above, the period of validity or storage period of the polarizing plate can be increased.

Such a polarizing plate is also applicable to various flat panel displays, preferably LCD panels and OLED panels, and is particularly applicable to OLED panels having a small amount of iodine-stained polarizer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims. In the following, "%" and "part" representing the content are on a mass basis unless otherwise specified.

Manufacturing example  1: Calcium Alginate  Particle synthesis

(1) Manufacturing

The reactor used for the preparation of the calcium alginate particles was a 2 L class, and 46 g of sodium alginate was completely dissolved by stirring in 500 ml of distilled water at 45 캜 for 24 hours. 500 ml of an aqueous sodium alginate solution and 60 ml of a surfactant (Tween 65, Sigma-Aldrich) were thoroughly stirred at 200 rpm through a stirrer to form a W / O emulsion in a reactor containing 1200 ml of hexadecane, , 5 ml of an aqueous phase prepared by dissolving 27.5 g of calcium chloride (CaCl 2 ) in 50 ml of distilled water was added dropwise thereto, and the mixture was stirred for 30 minutes.

The product was subjected to centrifugal dehydrator to remove hexadecane, the hexadecane-free particles were washed with hexane, and the water was removed using a freeze dryer to prepare calcium alginate particles having an average particle size of 0.1 to 2 탆.

(2) Measurement

In order to measure the moisture content of the prepared particles, it was put into a constant temperature and humidity device adjusted to the standard state ((20 ± 1 ° C., 65 ± 2% RH) by the Korean Industrial Standards KS K0220 method, After sufficiently drying at a temperature of 105 ± 2 ° C, the moisture content was calculated by the following formula 1 using the measured dry weight.

The moisture content of the prepared calcium alginate particles was confirmed to be 62.78%.

[Equation 1]

Moisture Regain (%) = W con - W dry / W dry X 100

W con : sample weight after conditioning

W dry : Sample weight after drying

Manufacturing example  2: Polyacrylamide  Particle synthesis

(1) Manufacturing

The polyacrylamide particles were prepared by dissolving 77.8 g of acrylamide and 15.6 g of N, N'-methylenebisacrylamide in 400 ml of distilled water and adding thereto a surfactant (Triton-X405, Sigma-Aldrich Corp. ) And 22.6 g of polyvinyl alcohol (PVA) (Mw = 9,000 to 10,000 g / mol, 80% hydrolyzed) are further dissolved. N, N ', N'-tetramethylenediamine (TMEDA, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to a 2L class double jacket reactor, and 940 ml of hexadecane was added thereto. , N, N, N ', N'-tetramethylenediamine) was added to the reaction mixture for 8 hours. After the reaction, the reaction mixture was washed with hexane and left for 12 hours without heating.

The washed particles were dried in a drying oven at 50 캜 for 10 hours to remove moisture to prepare polyacrylamide particles having an average particle size of 2 탆.

(2) Measurement

The moisture content of the obtained polyacrylamide particles was measured. The measurement method was as described in Preparation Example 1. The moisture content of the polyacrylamide particles produced was 55.27%.

Manufacturing example  3: Manufacture of surface protective film for optical film with 2-layer structure

The constituent resin of each layer of the surface protective film for an optical film having a two-layer structure according to the first embodiment of the present invention is as follows.

Adhesive layer (1): 50% by weight of linear low density polyethylene (hexene copolymerized polyethylene) having a density of 0.91 kg / m 3 and a MFR of 15 g / 10 min at 190 캜 as a pressure-sensitive adhesive layer resin, 30% by weight of a styrene-butadiene random copolymer of 10 g / 10 min and 20% by weight of water-absorbing particles was uniformly mixed with a Henschel mixer.

The 30 wt% master pellet of the hydrogenated terpenephenol was prepared by master pelletizing 40 wt% of the terpene phenol and 60 wt% of the linear low density polyethylene using a twin screw extruder.

(3): 45% by weight homopolypropylene having an MFR of 5 g / 10 min at 230 DEG C, 24% by weight (ethylene content: 5% by weight) of a propylene-ethylene random copolymer having an MFR of 35 g / Having a MFR of 2 g / 10 min and a density of 0.92 g / cm 3, and further containing 4 wt% of silica, a polyfluoro hydrocarbon group and a polyoxyethylene group in 90 wt% of the homopolypropylene 6% by weight was prepared as a master batch, and 25% by weight of the mixture was homogeneously mixed with a Henschel mixer.

Subsequently, using the resin for each layer prepared above, a T multifilament compound membrane having a punching width of 2400 mm having two extruders having a diameter of 90 mm (for a deposited layer) and a diameter of 65 mm (for a backing layer) was used, The composition was introduced into each extruder, and the discharge amount of each extruder was adjusted so that the ratio of the adhered layer thickness was 66% and the ratio of the back layer thickness was 34%, and extruded from the composite T-die at an extrusion temperature of 200 deg. Layer laminated film was once formed into a roll shape.

Manufacturing example  4: Manufacture of 3-layered surface protective film for optical film

The constituent resin of each layer of the surface protective film for an optical film having a three-layer structure according to the second embodiment of the present invention is as follows. At this time, the adhering layer 1 and the back layer 3 are as described in Production Example 3 above.

Intermediate layer (5): The same homopolypropylene as used for the back layer was used.

Next, using the resin for each layer prepared above, a T-type composite material block having a width of 2400 mm and three extruders each having Φ 90 mm (for a deposited layer), Φ 65 mm (for a back layer) and Φ 115 mm And the prepared resin composition was introduced into each of the extruders to adjust the discharge amount of each extruder so that the adhering layer thickness ratio was 15%, the back layer thickness ratio was 8%, and the intermediate layer thickness ratio was 77%, and the extrusion temperature Each was extruded at 200 DEG C, and a three-layer laminated film having a film thickness of 40 mu m was formed and once wound into a roll shape.

Example  1 to 5 and Comparative Example  1 to 7: Polarizing plate production

A polyvinyl alcohol film (VF-PS # 7500, manufactured by KURARAY Co.) having a thickness of 75 탆 and an average degree of polymerization of 2,400 and a degree of saponification of 99.9 mol% or more was uniaxially stretched by 6 times in a dry manner, After immersing for 1 minute, it was immersed in an aqueous solution of 28 DEG C having a weight ratio of iodine / potassium iodide / water of 0.013 / 5/100 for 60 seconds. Thereafter, it was immersed in an aqueous solution at 55 캜 for a period of 300 seconds in which the weight ratio of potassium iodide / boric acid / water was 11/10/100. Subsequently, the film was washed with water at 10 DEG C for 20 seconds, and then dried at 45 DEG C for 4 minutes to prepare a polarizer (PVA, 28 mu m) having iodine adsorbed orientation in a polyvinyl alcohol resin.

A polarizing plate was prepared by bonding a TAC film (40 CHC, TOPPAN yarn, 40 μm) on one side of the prepared polarizer using an adhesive with a laminator and drying in an oven at 50 ° C. for 3 minutes.

A protective film AY-638 (Fujimori Co., Ltd.) or a protective film obtained from the above-mentioned production example was attached to the upper surface of the polarizing plate having the TAC film laminated thereon. Next, ZK-PF (Dores Corp.) or the protective film produced in the above-mentioned production example was attached to one side where no protective film was formed. Thus, a polarizing plate having a final protective film / TAC film / PVA / protective film structure was prepared. The protective film and its application layer used here are in accordance with the compositions shown in Tables 1 and 2.

Protective film Example 1 Example 2 Example 3 Example 4 Example 5 Layer structure Second floor 3rd Floor 3rd Floor 3rd Floor 3rd Floor Water-absorbing particles
(Particle size and content) calcium
Alginate
(2 탆, 20% by weight) calcium
Alginate
(2 탆, 20% by weight) Polyacrylic
Amide
(2 탆, 20% by weight) mix

(2 탆, 20% by weight) calcium
Alginate
(2 탆, 20% by weight) Applicable layer bottom bottom bottom bottom Top and bottom

Protective film Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Layer structure Second floor 3rd Floor 3rd Floor 3rd Floor 3rd Floor 3rd Floor 3rd Floor Water-absorbing particles
(Particle size and content) - - - calcium
Alginate
(2 탆, 1% by weight) calcium
Alginate
(2 탆, 50% by weight) Sodium
Alginate
(2 탆, 20% by weight) calcium
Alginate
(10 탆, 20% by weight) Applicable layer bottom bottom Top and bottom bottom bottom bottom bottom

Experimental Example  1: Measurement of moisture content (% by weight) of protective film according to particle content for water absorption

The moisture content of the protective film was measured according to the content of the calcium alginate particles obtained in Preparation Example 1. The results are shown in FIG. The protective film of the optical film was based on the composition of Example 1, and the calcium alginate particles were changed to 15 wt%, 20 wt%, 25 wt%, and 30 wt%, respectively.

Referring to FIG. 9, it can be seen that as the content of calcium alginate increases, the moisture content of the protective film increases linearly, and the protective film effectively absorbs moisture.

Experimental Example  2: Measurement of the moisture content (% by weight) of the polarizing plate according to the particle content for water absorption

The water content of the polarizer was measured according to the content of the calcium alginate particles obtained in Preparation Example 1 in order to confirm the implementation of the low water-content polarizer according to the calcium alginate introduction. The results are shown in Table 3 below. The protective film of the optical film was based on the composition of Example 1, and the content of the calcium alginate particles was 1 wt%, 5 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 40 wt% 50% by weight, respectively, and they were attached to the lower part of the polarizing plate.

Calcium alginate content
(weight%) 0 One 5 15 20 25 30 40 50 Polarizer water content (% by weight) 5.3 5.3 2.5 2.2 2.1 1.9 1.9 1.8 1.8

Referring to Table 3, as the content of calcium alginate was increased, the water content of the polarizing plate was decreased and the water content of the polarizing plate was decreased from 5% by weight to 2% by weight. This decrease was almost unchanged at a certain level of content.

Experimental Example  3: Polarizer water content and polarizer reliability and curl evaluation after commercialization

In order to confirm the quality of the protective film containing water absorbing particles obtained in the above Examples and Comparative Examples, the moisture content was evaluated after the polarizing plate structure described in Tables 1 and 2 was produced.

(1) Polarizer water content (% by weight)

It is put into a constant temperature and humidity device controlled to the standard state (20 ± 1 ° C, 65 ± 2% RH) by Korean Industrial Standard KS K0220 method and sufficiently conditioned for 48 hours and sufficiently dried at 105 ± 2 ℃ The moisture content was calculated by the following formula 1 using the dry weight measured later.

[Equation 1]

Moisture Regain (%) = W con - W dry / W dry X 100

W con : sample weight after conditioning

W dry : Sample weight after drying

(2) Reliability evaluation

Next, after removing the protective film including moisture absorbing particles for making the antireflection OLED polarizing plate product, the polarizing plate was laminated on the OLED panel with a polarizer absorption axis of 45 ° and a retardation film (QWP, Teijin) And then stored for 500 hours and 250 hours under the conditions of high temperature (85 ° C) and high temperature and high humidity (60 ° C, 95% RH), respectively, and then staining, discoloration and curl were evaluated. The obtained results are shown in Tables 3 and 4 below. At this time, the reliability evaluation is as follows.

○: No color missing

X: stain and color dropout

(3) curl evaluation

In the curl measurement evaluation, the distance between the edge of the polarized plate and the edge of the commercialized polarizing plate was measured, and the distance between the edge and the ground was measured with the counterclockwise upper side, And the distance from the ground to the corner portion was measured with the lower surface facing upward. The MAX value was taken for the four corners, and it was measured as a total of N = 5 and averaged.

division Example 1 Example 2 Example 3 Example 4 Example 5 Before and after polarizer production
Moisture content
(weight%) Early
Polarizer water content 5.5 5.5 5.5 5.5 5.5 Protective film
Moisture content after lamination 2.1 2.3 2.5 2.3 2.0 After polarizer production Reliability evaluation High temperature ○ ○ ○ ○ ○ Hot and humid ○ ○ ○ ○ ○ curl
evaluation Static 0 One One 0 0 Counterfeit 0 -One -One 0 0 Secondary Curl 0 -One 0 -One -One

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Before and after polarizer production
Moisture content
(weight%) Initial Polarizer Plate Moisture Content 5.5 5.5 5.5 5.5 5.5 5.5 5.5 Protective film
Moisture content after lamination 5.1 5.2 5.2 5.0 2.1 4.7 2.2 After polarizer production Reliability evaluation High temperature X X X X ○ X ○ Hot and humid X X X X ○ X ○ curl
evaluation Static 3 3 5 5 One 3 One Counterfeit -4 -3 -4 -2 -One -3 0 Secondary Curl -9 -9 -10 -9 -One -4 -One

Referring to Table 4, it can be seen that the moisture content of the polarizing plate decreases when the protective film containing the water absorbing particles is laminated according to the present invention.

10, no color unevenness was observed in all of Examples 2 to 3 and Comparative Example 2 immediately after commercialization, but after storage at high temperature for a long time and under high temperature and high humidity conditions, color separation and unevenness were not observed only in Examples 2 to 3 .

In comparison, Table 5 shows experimental results of the polarizer according to the comparative example for evaluating the moisture content, curl and reliability of the polarizer.

Specifically, in Comparative Examples 1, 2 and 3, it was impossible to make a low-moisture polarizing plate using a protective film that does not contain water-absorbing particles, thereby causing stain and color dropout in the reliability evaluation, Respectively. Also, Comparative Example 6 containing sodium alginate particles had poor water absorption ability, and the results were similar to those of Comparative Examples 1, 2, and 3.

In Comparative Examples 5 and 7, the evaluation of reliability according to the low-moisture polarizing plate confirmed that curl, color drop, and smear phenomenon were good. However, in Comparative Example 5, when the calcium alginate particles were used in an excess amount of 50% by weight, the adhesion between the adhesive layer and the polarizing plate was weakened, resulting in partial interlayer peeling and weakening of the tensile strength. In Comparative Example 7 using 10 탆 calcium alginate particles, the polarizing film produced a dimple-like shape, and transparency was not good depending on the particle size. Therefore, it was confirmed that depending on the content and size of the water-absorbing particles, not only tackiness but also physical properties such as transparency, flexibility, and tensile strength as a film were affected.

From these results, it can be understood that when the content and particle size of the water-absorbing particles are controlled according to the present invention, a polarizer having a low water content can be realized.

The surface protective film for an optical film according to the present invention is introduced into a polarizing plate to provide a high transparency polarizing plate having a good moisture resistance and durability and an effect of suppressing curling and has a low water content and is also applicable to various flat panel displays, A flat panel display device can be realized.

1: Deposited layer 3: Back layer
5: intermediate layer 101: lower protective film
103: Polarizer 105: Adhesive
107: TAC 109: Top protective film
111: Pressure sensitive adhesive 113:

Claims (14)

A surface protective film for an optical film in which an adhering layer and a backing layer are sequentially laminated,
Wherein the adhered layer comprises one kind of water-absorbing particles selected from the group consisting of metal alginate, polyacrylamide, and combinations thereof. A surface protective film for an optical film in which an adhered layer, an intermediate layer and a back layer are sequentially laminated,
Wherein at least one of the adhered layer and the intermediate layer comprises one kind of water-absorbing particles selected from the group consisting of metal alginate, polyacrylamide, and combinations thereof. The surface protective film for an optical film according to claim 1 or 2, wherein the water-absorbing particles have an average particle diameter of 0.1 to 2.5 탆. The surface protective film for an optical film according to claim 1 or 2, wherein the moisture-absorbing particles comprise 5 to 40% by weight in the entire composition of the adhered layer. The surface protective film for an optical film according to claim 1 or 2, wherein the metal alginate is one kind of divalent alkali metal alginate selected from the group consisting of calcium alginate, barium alginate, strontium alginate, and combinations thereof. The water absorbing composition according to claim 1 or 2, wherein the water absorbing particles further comprise modified alginate, chitosan, cyclodextrin, hyaluronic acid, agarose, starch, carrakinan, gum arabic, xanthan gum, carboxymethyl cellulose, gelatin, pectin, A natural polymer selected from the group consisting of collagen, fibrin, and combinations thereof; And
(C2-C3) alkylene oxide, polyhydroxybutyrate (PHB), polystyrene, polyvinylpyrrolidone (PVP), polyvinyl pyrrolidone ), A synthetic polymer selected from the group consisting of polyacrylic acid, polymaleic acid, polyglycolic acid, polylactic acid, polycaprolactone, and copolymers thereof;
And a combination of these materials. The surface protective film for optical films according to claim 1, The adhesive layer according to claim 1 or 2, wherein the adhered layer comprises 30 to 90% by weight of low density polyethylene, 5 to 40% by weight of a styrene elastomer, and 0 to 15% by weight of a polyurethane within 100% by weight of the total adhered layer composition Wherein the surface protective film for optical film is a film. The surface protective film for an optical film according to claim 1 or 2, wherein the back layer comprises 90 to 99.5% by weight of polypropylene and 0.05 to 10% by weight of an inorganic filler. The surface protective film for an optical film according to claim 2, wherein the intermediate layer comprises polypropylene. The surface protective film for an optical film according to claim 1, wherein the adhesion layer of the surface protective film for an optical film has a thickness of 3 to 50 탆 and the thickness of the back surface layer is 2 to 50 탆. The optical film according to claim 2, wherein the adhesion layer of the surface protective film for an optical film has a thickness of 3 to 20 占 퐉, a thickness of the intermediate layer is 10 to 100 占 퐉, and a thickness of the backing layer is 2 to 10 占 퐉. Surface protection film. Upper and lower protective films; And a polarizer interposed therebetween,
Wherein one of the upper and lower protective films is a surface protective film for an optical film according to any one of claims 1 and 2. The method of claim 12,
Wherein the polarizer is a low-moisture-content polarizer having a water content of less than 3% by weight. The polarizing plate according to claim 12, wherein the surface protective film is a release film.
KR1020140150030A 2014-10-31 2014-10-31 Surface protective film for optical film and polarizer comprising thereof KR20160050887A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020140150030A KR20160050887A (en) 2014-10-31 2014-10-31 Surface protective film for optical film and polarizer comprising thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020140150030A KR20160050887A (en) 2014-10-31 2014-10-31 Surface protective film for optical film and polarizer comprising thereof

Publications (1)

Publication Number Publication Date
KR20160050887A true KR20160050887A (en) 2016-05-11

Family

ID=56025756

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020140150030A KR20160050887A (en) 2014-10-31 2014-10-31 Surface protective film for optical film and polarizer comprising thereof

Country Status (1)

Country Link
KR (1) KR20160050887A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2018230525A1 (en) * 2017-06-14 2020-04-30 パナソニックＩｐマネジメント株式会社 Display device and method of manufacturing display device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2018230525A1 (en) * 2017-06-14 2020-04-30 パナソニックＩｐマネジメント株式会社 Display device and method of manufacturing display device

Similar Documents

Publication Publication Date Title
EP2711765B1 (en) Liquid crystal display device, use of polarizer, use of protective film
JP6811549B2 (en) Laminated film and image display device
JP5850135B2 (en) Polyester film for protecting polarizer, polarizing plate and liquid crystal display device
TW200842416A (en) Optical film, polarizing plate, and image display apparatus
TW201617646A (en) Polarizing plate
TW201137460A (en) A liquid crystal display device
KR20100068178A (en) Polarizing plate and liquid crystal display device comprising the same
JP2013210598A (en) Polyester film for protecting polarizing plate
TWI708968B (en) Manufacturing method of image display device and image display device manufactured by the manufacturing method
WO2017115784A1 (en) Polarizer protection film and method for manufacturing same, polarizer, and liquid-crystal display device
KR102473609B1 (en) Method for manufacturing laminated polarizing plate and method for manufacturing polarizing plate
CN111480100B (en) Laminate for polarizing plate, laminate film roll, and method for producing same
TWI682852B (en) Coating film for protecting optical components
TW202027990A (en) Polarizing plate
KR20160050887A (en) Surface protective film for optical film and polarizer comprising thereof
JP6024271B2 (en) Acrylic film for protecting polarizer, polarizing plate, and liquid crystal display device
TW201601917A (en) Multilayer film and wound body
KR102607551B1 (en) Easily adhesive film and manufacturing method thereof, polarizing plate, and image display device
TW201842365A (en) Image display device production method, and image display device
TWI828805B (en) Polyester film and polarizing plate containing the polyester film
KR20070116309A (en) Adhesive and polarizing plate
KR20220079700A (en) Optical film, production method thereof, polarizer, and image display device
JP6587901B2 (en) Uniaxially stretched multi-layer easily adhesive film and optical member using the same
KR20130135782A (en) Polarizing plate and image display apparatus comprising the same
JP6160038B2 (en) Polyester film for polarizer protection

Legal Events

Date Code Title Description
WITN Withdrawal due to no request for examination