KR20150017446A - Polarizing plate and preparing method thereof - Google Patents

Abstract

The present invention relates to a polarizing plate and a manufacturing method thereof. More specifically, the polarizing plate includes: a polarizer which is plasma-discharge treated by a gas including the compound which has an unsaturated bond and includes a hydroxy group, a carboxy group, an ester group, or a hydroxyl group; and a protection film which is attached to the processed surface of the polarizer with a photo-curing adhesive agent. The present invention can significantly increase the adhesion between the polarizer and the protection film while ensuring excellent durability and heat and water resistance. Accordingly, the adhesion can be maintained even when the plate is exposed to high temperature and humidity conditions for a long time.

Description

[0001] The present invention relates to a polarizing plate and a polarizing plate,

The present invention relates to a polarizing plate and a manufacturing method thereof.

Polarizing plates used in various image display devices such as a liquid crystal display (LCD), an electroluminescence (EL) display, a plasma display (PDP), a field emission display (FED) and an OLED are generally made of polyvinyl alcohol alcohol, PVA) film comprises a polarizer in which an iodine compound or a dichroic polarizing material is adsorbed and oriented, a polarizer protective film is laminated on one side of the polarizer, and a polarizer protective film, a liquid crystal cell Layer structure in which a pressure-sensitive adhesive layer and a release film are laminated in this order.

2. Description of the Related Art In recent years, various types of image display devices have become larger and larger, and accordingly polarizers and polarizing plates used are also becoming larger. Therefore, the handling becomes more disadvantageous in the handling process in the process, and the amount of deformation generated under repeated high temperature and low temperature environments during use is further increased, and a polarizer excellent in durability is required.

The polarizer and the protective film are bonded together by an adhesive interposed therebetween. When the adhesion between the polarizer and the protective film is poor, deformation may occur during handling or use during processing. When the film is exposed to a long- A phenomenon may occur. Therefore, the adhesive plays an important role in the durability of the polarizing plate.

However, since a polarizer having a low shrinkage and a high durability is required and cross-linking is performed so as to have a high degree of crosslinking, the number of hydroxy groups distributed on the surface of the polarizer is reduced and it is difficult to have a sufficient adhesive force. Particularly, This can be significantly reduced.

Accordingly, there is a need to develop a polarizing plate having both low shrinkage and high durability and excellent adhesive strength at the same time.

Korean Patent Laid-Open Publication No. 2009-82197 discloses a polarizer protective film, a polarizing plate, and an image display device, but fails to provide an alternative to the above problem.

Korea Patent Publication No. 2009-82197

An object of the present invention is to provide a polarizing plate in which the adhesive force between a polarizer and a protective film is remarkably improved.

An object of the present invention is to provide a polarizing plate excellent in water resistance at room temperature and having excellent durability.

An object of the present invention is to provide a polarizing plate having an excellent adhesive force even when exposed to high temperature and high humidity for a long time.

It is an object of the present invention to provide a method for producing such a polarizing plate.

1. A polarizer comprising a polarizer having an unsaturated bond and subjected to a plasma discharge treatment with a gas containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group, and a protective film bonded to the treatment surface of the polarizer with a photo- , A polarizer.

2. The composition according to 1 above, wherein the compound having a unsaturated bond and containing a hydroxyl group is selected from allyl alcohol, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl ) Acrylate. ≪ / RTI >

3. The polarizer of claim 1, wherein the compound having a unsaturated bond and containing a carboxyl group is at least one of (meth) acrylic acid and 2-carboxyethyl acrylate.

4. The composition according to item 1, wherein the compound having an unsaturated bond and containing an ester group is selected from the group consisting of vinyl (meth) acrylate, glycidyl (meth) acrylate, methyl (meth) acrylate, (Meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and propyl (meth) acrylate.

5. The polarizer according to item 1, wherein the compound having an unsaturated bond and containing a hydroxyl group is diallyl polycarbonate.

6. The polarizer according to item 1 above, wherein the compound having an unsaturated bond and containing a hydroxyl group is a cyclic acid anhydride.

7. The method of claim 6, wherein the cyclic acid anhydride is selected from the group consisting of maleic anhydride, citraconic anhydride, itaconic anhydride, 2-dodecene-1-yl succinic anhydride, 2H-pyran-2,6 (3H) (3H) -dione and 3-methylene dihydro-2H-pyran-2,6 (3H) -Dione. ≪ / RTI >

8. The polarizing plate according to item 1 above, wherein the plasma-treated surface of the polarizer comprises a hydroxyl group or a carboxyl group.

9. The polarizer of claim 1, wherein the polarizer is a polyvinyl alcohol film, a dehydrated polyvinyl alcohol film, a dehydrochlorinated acid-treated polyvinyl alcohol film, a polyethylene terephthalate film, an ethylene-vinyl acetate copolymer film, an ethylene- A cellulose film, or a partially saponified film thereof.

10. The protective film according to 1 above, wherein the protective film is selected from the group consisting of a polyester film, a cellulose film, a polycarbonate film, an acrylic film, a styrene film, a polyolefin film, a vinyl chloride film, a polyamide film, Based film, a polyether ketone-based film, a sulfide polyphenylene-based film, a vinyl alcohol-based film, a vinylidene chloride film, a vinyl butyral film, an allylate film, a polyoxymethylene film, a urethane- A polarizer, which is a silicon-based film.

11. A method of manufacturing a plasma display panel, comprising: plasma-treating at least one surface of a polarizer with a gas having an unsaturated bond and containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group; And bonding the protective film to the processed surface of the polarizer with a photo-curable adhesive.

12. The composition according to 11 above, wherein the compound having a hydroxyl group and having an unsaturated bond is selected from the group consisting of allyl alcohol, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl ) Acrylate. ≪ / RTI >

13. The method of producing a polarizing plate according to 11 above, wherein the compound having an unsaturated bond and containing a carboxyl group is at least one of (meth) acrylic acid and 2-carboxyethyl acrylate.

14. The composition of claim 11 wherein the compound having an unsaturated bond and containing an ester group is selected from the group consisting of vinyl (meth) acrylate, glycidyl (meth) acrylate, methyl (meth) acrylate, ethyl (Meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and propyl (meth) acrylate.

15. The method for producing a polarizing plate according to 11 above, wherein the compound having an unsaturated bond and containing a hydroxyl group is diallyl polycarbonate.

16. The method for producing a polarizing plate according to 11 above, wherein the compound having an unsaturated bond and containing a hydroxyl group is a cyclic acid anhydride.

17. The method of claim 16, wherein the cyclic acid anhydride is selected from the group consisting of maleic anhydride, citraconic anhydride, itaconic anhydride, 2-dodecene-1-ylsuccinic anhydride, 2H-pyran-2,6 (3H) (3H) -dione and 3-methylene dihydro-2H-pyran-2,6 (3H) -Dione. ≪ / RTI >

18. The method of producing a polarizer according to 11 above, wherein the compound is contained in an amount of 1 to 5% by volume of the total gas volume.

19. The production method of a polarizing plate according to 11 above, wherein the applied voltage for the plasma discharge treatment is 1 to 10 kV.

20. The production method of a polarizing plate according to 11 above, wherein the operating frequency of the power source of the plasma discharge processing apparatus is from 1 kHz to 150 MHz.

21. The method for producing a polarizing plate according to 11 above, wherein the inter-electrode distance of the plasma discharge processing apparatus is 0.5 to 50 mm.

The polarizing plate of the present invention is remarkably excellent in adhesion between the polarizer and the protective film.

The polarizing plate of the present invention is excellent in durability because of excellent temperature resistance at room temperature.

The polarizing plate of the present invention can maintain excellent adhesion even when exposed for a long time under high temperature and high humidity conditions.

The present invention includes a polarizer having an unsaturated bond and subjected to a plasma discharge treatment with a gas containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group, and a protective film bonded to the treated surface of the polarizer with a photo- To a polarizing plate capable of maintaining excellent adhesiveness even when exposed under a high temperature and a high humidity condition for a long time, and a method for producing the polarizing plate, which can remarkably improve the adhesion between the polarizer and the protective film,

A polyvinyl alcohol film is usually used in the production of a polarizer. When a polyvinyl alcohol polarizer is bonded to a protective film through an adhesive, a hydroxyl group distributed on the surface of the polarizer reacts with a polar group present on the protective film surface, I have.

However, since a low shrinkage and high durability polarizer is required and crosslinking is performed so as to have a high degree of crosslinking, the number of hydroxyl groups distributed on the surface of the polarizer decreases, making it difficult to have sufficient adhesion.

Accordingly, the present invention increases the density of the hydroxyl group or carboxyl group on the surface of the polarizer by plasma discharge treatment of the polarizer with a gas containing an unsaturated bond and containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group, The adhesion with the protective film is remarkably improved.

Hereinafter, the present invention will be described in detail with reference to an embodiment of the present invention.

The polarizing plate of the present invention comprises a polarizer having an unsaturated bond and subjected to plasma discharge treatment with a gas containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group, and a protective film bonded to the treatment surface of the polarizer with a photo- .

The polarizer according to the present invention is a polarizer having an unsaturated bond and subjected to plasma discharge treatment with a gas containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a non-hydroxyl group to introduce a hydroxyl group or a carboxyl group into the surface thereof, And the water resistance and peel strength at the temperature resistance are remarkably improved. An ester group and a hydroxyl group are introduced, the adhesion is remarkably improved, which is judged to be due to hydration by a hydroxyl group, an epoxy group, moisture contained in the adhesive to be described later, and a hydroxyl group or a carboxyl group.

The plasma discharge treatment may be performed on one side or both sides of the polarizer.

The gas used in the plasma discharge treatment has an unsaturated bond and contains a compound containing a hydroxyl group, a carboxyl group, an ester group or a non-hydroxyl group.

The compound having an unsaturated bond and having a hydroxyl group has an unsaturated bond so as to be bonded to the carbon skeleton of the polarizer by a radical generated by a plasma discharge treatment and is not particularly limited as long as it is a compound having a hydroxy group, Compounds such as allyl alcohol, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate can be used. These may be used alone or in combination of two or more.

Similarly, the compound having an unsaturated bond and having a carboxyl group is not particularly limited and includes, for example, (meth) acrylic acid, 2-carboxyethyl acrylate and the like. These may be used alone or in combination of two or more.

Similarly, the compound having an unsaturated bond and having an ester group is not particularly limited, and examples thereof include vinyl (meth) acrylate, glycidyl (meth) acrylate, methyl (meth) acrylate, ethyl Butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and propyl (meth) acrylate. These may be used alone or in combination of two or more.

Similarly, the compound having an unsaturated bond and having a hydroxyl group is not particularly limited, and for example, diallyl polycarbonate and the like can be given. These may be used alone or in combination of two or more.

Preferably, the present invention has the above unsaturated bond, and the compound having a hydroxyl group may be a cyclic acid anhydride. By carrying out the plasma discharge treatment with a gas containing a cyclic acid anhydride having an unsaturated bond, two carboxyl groups can be introduced to the surface of the polarizer per one molecule of the cyclic acid anhydride, and thus the adhesion improving effect is excellent.

The compound having a non-hydroxyl group and having the unsaturated bond is not particularly limited, and examples of the cyclic acid anhydride include maleic anhydride, citraconic anhydride, itaconic anhydride, 2-dodecen-1-yl succinic anhydride , 2H-pyran-2,6 (3H) -dione, 5-methyl-2H-pyran-2,6 (3H) Methylene dihydro-2H-pyran-2,6 (3H) -dione and the like. These may be used alone or in combination of two or more.

The polarizer according to the present invention may be a polarizer commonly used in the art, which is produced according to a process including a step of swelling, dyeing, crosslinking, stretching, washing, drying, and the like.

The type of the polarizer-forming film is not particularly limited as long as it is a dichroic substance, that is, a film which can be dyed with iodine. Examples thereof include a polyvinyl alcohol film, a dehydrated polyvinyl alcohol film, a dehydrochlorinated polyvinyl alcohol film, Polyethylene terephthalate film, ethylene-vinyl acetate copolymer film, ethylene-vinyl alcohol copolymer film, cellulose film, partially saponified film thereof and the like. Of these, a polyvinyl alcohol-based film is preferable because it has an excellent effect of enhancing the uniformity of the degree of polarization in the plane and is excellent in dye affinity for iodine.

The thickness of the film for forming a polarizer is not particularly limited, and may be, for example, 10 to 150 mu m.

The swelling step is carried out by immersing the polarizer-forming film in a swelling tank filled with an aqueous swelling solution before dyeing to remove impurities such as dust and anti-blocking agent deposited on the surface of the polarizer-forming film, swelling the polarizer- Is a step for improving the physical properties of the polarizer by improving the efficiency and preventing the uneven dyeing.

Water (pure water, deionized water) can usually be used as a swelling aqueous solution, and when a small amount of glycerin or potassium iodide is added thereto, the swelling of the polymer film and the processability can be improved.

The content of glycerin and potassium iodide is not particularly limited and may be, for example, 5 wt% or less and 10 wt% or less, respectively, in the total weight of the aqueous swelling solution.

The temperature of the swelling bath is not particularly limited, and may be, for example, 20 to 70 캜, preferably 25 to 55 캜. When the temperature of the swelling bath is 20 to 70 캜, the stretching and dyeing efficiency is excellent thereafter, and expansion of the film due to excessive swelling can be prevented.

The execution time (swelling bath immersion time) of the swelling step is not particularly limited, and may be, for example, 180 seconds or less, preferably 90 seconds or less. It is possible to prevent excessive swelling and saturation when the immersion time is 180 seconds or less, to prevent breakage due to softening of the polyvinyl alcohol-based film and to improve the polarization degree by uniformly adsorbing iodine in the dyeing step have.

The swelling step is performed as needed, and can be omitted.

The dyeing step is a step of dipping the polarizing film in a dyeing bath filled with a dyeing aqueous solution containing a dichroic substance, for example, iodine, to adsorb iodine to the polarizing film.

The dyeing aqueous solution may comprise water, a water-soluble organic solvent or a mixed solvent thereof and iodine. The content of iodine may be 0.01 to 1 part by weight based on 100 parts by weight of water.

The dyeing aqueous solution may further contain iodide as a solubilizing aid for improving the dyeing efficiency.

The kind of iodide is not particularly limited and includes, for example, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide and the like , And potassium iodide is preferred in view of high solubility in water. These may be used alone or in combination of two or more.

The content of iodide is not particularly limited and may be, for example, 0.5 to 20 parts by weight based on 100 parts by weight of water.

As the dichroic material, a dichroic dye may also be used. In this case, the dichroic dye may be contained in an amount of 1 * 10 ^-4 to 10 parts by weight, preferably 1 * 10 ^-3 to 1 part by weight, .

The temperature of the dye bath is not particularly limited and may be, for example, 5 to 45 캜, and preferably 10 to 35 캜.

The immersion time of the film for forming a polarizer in the dyeing tank is not particularly limited and may be, for example, 20 seconds to 30 minutes, preferably 2 to 10 minutes.

The cross-linking step is a step of immersing the dyed polarizer-forming film in a crosslinking aqueous solution so as to fix the adsorbed iodine molecules so that the dyeability due to physically adsorbed iodine molecules is not lowered by the external environment. Although dichroic dyes are not often eluted in a humidity environment, iodine molecules often dissolve or sublimate depending on the environment when the crosslinking reaction is unstable, and sufficient crosslinking reaction is required.

The aqueous solution for crosslinking may further comprise water as a solvent and a boron compound such as boric acid or sodium borate, and may further comprise an organic solvent mutually soluble with water.

The boron compound imparts rigidity to the polarizer-forming film to suppress the occurrence of wrinkles in the process, thereby improving the handling property and forming the iodine orientation.

The content of the boron compound is not particularly limited and may be, for example, 2 to 15 parts by weight, and preferably 5 to 12 parts by weight based on 100 parts by weight of water.

The aqueous crosslinking solution may further contain a small amount of iodide to obtain the uniformity of the degree of polarization in the plane of the polarizer.

The iodide may be the same as that used in the dyeing step.

The content of iodide is not particularly limited and may be, for example, 0.1 to 15 parts by weight, and preferably 5 to 12 parts by weight based on 100 parts by weight of water. If the content of iodide is less than 0.1 parts by weight with respect to 100 parts by weight of water, the iodide ions in the film may escape to increase the transmittance and change the color of the polarizer. If the content of iodide is more than 15 parts by weight, Can be reduced.

The temperature of the crosslinking bath is not particularly limited and may be, for example, 50 ° C or higher, preferably 50 to 85 ° C, more preferably 60 to 80 ° C.

The immersion time of the film for forming a polarizer in the crosslinking bath may be 60 seconds to 1,200 seconds, preferably 150 to 600 seconds, more preferably 200 to 400 seconds.

The order of the stretching step is not particularly limited, and may be performed before, after, or after the dyeing step, and may be performed simultaneously with at least one step selected from the group consisting of a swelling step, a dyeing step and a crosslinking step .

The stretching ratio of the stretching step is not particularly limited, and may be, for example, such that the cumulative stretching ratio is 4 to 8 times. When the cumulative stretching ratio is within the above range, the effect of improving the durability of the polarizer can be maximized. In the present specification, "cumulative stretching ratio" represents the value of the product of the stretching ratio at each step.

The washing step is a step of immersing the crosslinked and stretched polarizer forming film in a water bath filled with aqueous solution for washing to remove unnecessary residues such as boric acid attached to the polarizing film in the previous steps.

The aqueous solution for washing may be water (deionized water).

The temperature of the water bath is not particularly limited and can be, for example, 5 to 60 ° C, and preferably 10 to 40 ° C.

The immersion time of the polarizer-forming film in the water bath may be 1 to 120 seconds.

The wash step may be performed each time previous steps such as dyeing step, crosslinking step or stretching step are completed. It may also be repeated one or more times, and the number of repetition is not particularly limited.

The drying step is a step of drying the washed polyvinyl alcohol-based film and further improving the orientation of the iodine molecules dyed by the necking by drying, thereby obtaining a polarizer excellent in optical characteristics.

Examples of the drying method include natural drying, air drying, heat drying, far-infrared drying, microwave drying, hot air drying and the like.

The drying temperature is not particularly limited and can be, for example, 30 to 100 ° C, preferably 50 to 80 ° C.

The drying time is not particularly limited and can be suitably performed so that the polarizer can be sufficiently dried, and can be performed, for example, for 1 to 10 minutes, preferably for 2 to 10 minutes.

The thickness of the polarizer manufactured through the above process may be 5 to 40 탆, and the contact angle of the surface water may be 50 캜 or more. In particular, when the content of boric acid in the crosslinking bath, the drying temperature, and the time are controlled in order to produce a low shrinkage and highly durable polarizer, the water contact angle may be 60 ° or more.

The protective film is bonded to at least one surface of the polarizer including the plasma discharge treated surface.

The protective film is not particularly limited as long as it is a film excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like. Specifically, polyester films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate; Cellulose-based films such as diacetylcellulose and triacetylcellulose; Polycarbonate-based films; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene-based films such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin films such as cycloolefin, cycloolefin copolymer, polynorbornene, polypropylene, polyethylene, and ethylene propylene copolymer; Vinyl chloride film; Polyamide-based films such as nylon and aromatic polyamide; Imidazole film; Sulfone based films; Polyether ketone-based films; A sulfided polyphenylene-based film; Vinyl alcohol film; Vinylidene chloride films; Vinyl butyral film; Allylate-based films; Polyoxymethylene-based films; Urethane-based films; Epoxy-based films; Silicone-based films, and the like. Among them, a cellulose-based film having a surface saponified (saponified) by alkali or the like is preferable in consideration of polarization characteristics or durability. The protective film may also have an optical compensation function such as a retardation function.

The protective film may contain one or more suitable additives. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, coloring inhibitors, flame retardants, nucleating agents, antistatic agents, pigments and colorants.

The protective film may be one in which an easy-bonding process for improving the bonding strength has been performed on the surface to be bonded to the polarizer.

The bonding facilitating treatment is not particularly limited as long as the bonding strength between the polarizer and the protective film can be improved. For example, dry treatment such as primer treatment, plasma treatment and corona treatment; Chemical treatment such as alkali treatment (saponification treatment); Low-pressure UV treatment and the like.

The thickness of the protective film is not particularly limited, and may be, for example, 10 to 200 mu m, and preferably 10 to 150 mu m.

The photo-curable adhesive composition is cured by light irradiation to bond the polarizer and the protective film.

The photo-curable adhesive composition according to the present invention provides an excellent adhesive force so that the peeling force is not degraded under the aged and anti-wet heat environment of the polarizer and the protective film treated by the plasma discharge.

The photocurable adhesive composition may comprise a photopolymerizable compound and a photopolymerization initiator.

The photopolymerizable compound may be a photo-radical polymerizable compound or a photo-cationic polymerizable compound.

Examples of the photo-radical polymerizable compound include monofunctional monomers such as methyl (meth) acrylate, allyl methacrylate, 2-ethoxyethyl (meth) acrylate, isodecyl (Meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2-hydroxyethyl (Meth) acrylate, isooctyl (meth) acrylate, isooctyl (meth) acrylate, stearyl (meth) acrylate, tetrapurfuryl ) Monofunctional monomers such as acrylate, dimethylaminoethyl (meth) acrylate and the like; Butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, bisphenol A- (Meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (Meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl (meth) acrylate, ethylene oxide modified di (meth) acrylate, bis (Hydroxyethyl) isocyanurate di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylcyclohexyl di (meth) acrylate, dimethyloldicyclopentane diacrylate , Ethylene oxide-modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol diacrylate, neopentyl glycol-modified trimethylolpropane diacrylate, adamantyl bifunctional monomers such as tandi acrylate; (Meth) acrylate such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional monomers such as tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, glycerol tri ; Tetrafunctional monomers such as diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ditrimethylol propane tetra (meth) acrylate; Pentafunctional monomers such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And caprolactone-modified dipentaerythritol hexa (meth) acrylate. Of these, mono- to trifunctional monomers are preferable. These may be used alone or in combination of two or more.

Examples of the photo cationic polymerizable compound include bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; Novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; Aliphatic epoxy resins, alicyclic epoxy resins, naphthalene type epoxy resins, polyfunctional epoxy resins, biphenyl type epoxy resins, glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins; Alcohol type epoxy resins such as hydrogenated bisphenol A type epoxy resins; Halogenated epoxy resins such as brominated epoxy resins; An epoxy group-containing compound such as a rubber-modified urethane resin, a urethane-modified epoxy resin, an epoxidized polybutadiene, an epoxidized styrene-butadiene-styrene block copolymer, an epoxy group-containing polyester resin, an epoxy group-containing polyurethane resin and an epoxy group- (Phenoxymethyl) oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl- (3-ethyl-3 - {[3- (triethoxysilyl) propoxy] methyl} oxetane, phenol novolak oxetane, 1,4-bis { (3-ethyl-3-oxetanyl) methoxy] methyl} benzene, etc. These compounds may be used singly or in combination of two or more.

The photopolymerization initiator is used for improving the efficiency of the curing reaction. Examples thereof include photo radical polymerization initiators such as acetophenone, benzophenone, thioxanthone, benzoin and benzoin alkyl ether; Aromatic diazonium salts, aromatic sulfonium salts, aromatic iodo aluminum salts, and benzoin sulfonic acid esters. Examples of the photo cationic polymerization initiator include commercially available products such as Opethoma-SP-151, Opethama-SP-170, Opethoma-SP-171 (Asahi Kogyo Co.), IGACURE- 103, NTS-103, NDS-103 (Midori Chemical), CPI-110A (Sanfrasa), etc. . These may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited and may be, for example, 0.5 to 10 parts by weight based on 100 parts by weight of the photopolymerizable compound. When the content is within the above range, it has a proper curing rate and has excellent durability.

The coating method of the photocurable adhesive composition is not particularly limited and a known method can be used in the art. Examples of the coating method include a bar coater, an air knife, a gravure, a reverse roll, a kiss roll, a spray, a blade, a die coater, Coating or the like can be used.

The coating thickness of the photocurable adhesive composition is not particularly limited, and may be coated to, for example, 0.01 to 10 탆, preferably 0.5 to 5 탆.

The present invention also provides a method for producing the polarizing plate.

Hereinafter, one embodiment of the method for producing a polarizing plate of the present invention will be described in detail.

First, at least one surface of the polarizer is subjected to plasma discharge treatment with a gas containing a cyclic acid anhydride having an unsaturated bond.

By subjecting at least one surface of the polarizer to a plasma discharge treatment with a gas containing an unsaturated bond and containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group, the compound is reacted with a radical generated by a plasma discharge treatment Bonded to the carbon skeleton, the density of the hydroxyl group or the carboxyl group on the surface of the polarizer is increased. This is combined with the polar group on the surface of the protective film to remarkably improve the adhesion between the polarizer and the protective film. An ester group and a non-hydroxyl group.

The compound having an unsaturated bond and containing a hydroxyl group, a carboxyl group, an ester group or a non-hydroxyl group may be the compound described above.

Preferably, the present invention has the above unsaturated bond, and the compound having a hydroxyl group may be a cyclic acid anhydride. By carrying out the plasma discharge treatment with a gas containing a cyclic acid anhydride having an unsaturated bond, two carboxyl groups can be introduced to the surface of the polarizer per one molecule of the cyclic acid anhydride, and thus the adhesion improving effect is excellent.

The compound having an unsaturated bond and having a hydroxyl group may be a cyclic acid anhydride as described above.

The gas used for the plasma discharge treatment further includes an inert gas used for the movement of the compound. For example, nitrogen, argon, helium and the like. These may be used alone or in combination of two or more.

The content of the compound having an unsaturated bond and including a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group is not particularly limited and may be, for example, 1 to 5% by volume in total gas volume, preferably 3 to 5% % ≪ / RTI > When the content is less than 1 vol%, the effect of improving the adhesion may be insufficient. When the content is more than 5 vol%, a hydroxy group or a carboxyl group is excessively introduced to make it impossible to react with all the polar groups on the surface of the protective film. The adhesive force may be lowered.

A compound having an unsaturated bond and containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group is vaporized in a heatable vaporizer and contained in the gas.

The temperature of the vaporizer is not particularly limited and may be, for example, 50 to 200 ° C.

The flow rate of the gas flowing into the plasma discharge treatment treatment can be appropriately adjusted by the temperature of the vaporizer and the flow rate of the inert gas.

The voltage applied to generate the plasma is not particularly limited, and may be, for example, 1 to 10 kV.

The operating frequency of the power source is not particularly limited. For example, the operating frequency of the power source may be in the range of 1 KHz to 150 MHz, and may be in the higher GHz range. In view of minimizing the thermal deformation of the plasma- .

The distance between the electrodes of the plasma apparatus is determined in consideration of the pressure and concentration of the base gas, the thickness of the solid dielectric, the magnitude of the applied voltage, etc. Generally, if the distance between the electrodes is short, a stable discharge plasma tends to be obtained.

In the case of the present invention, the inter-electrode distance may be 0.5 to 50 mm. When the distance between the electrodes is less than 0.5 mm, the concentration of the gas in the base gas varies greatly between the electrodes, the activation treatment may be uneven, and the thickness of the object to be disposed between the electrodes becomes limited. In addition, when the interelectrode distance exceeds 50 mm, it may be difficult to generate a uniform discharge plasma.

As the polarizer, the polarizer described above can be used.

Thereafter, a protective film is bonded to the treated surface of the polarizer with a photo-curable adhesive.

As the photo-curable adhesive composition and protective film, the above-described composition and protective film may be used.

The coating thickness of the photocurable adhesive composition is not particularly limited, and may be coated to, for example, 0.01 to 10 탆, preferably 0.5 to 5 탆.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

Manufacturing example  One. Polarizer  Produce

A polyvinyl alcohol film having a thickness of 75 탆 and an average degree of polymerization of 2,400 and a saponification degree of 99.9 mol% or more was uniaxially stretched by a dry method about 5 times and immersed in water (distilled water) at 60 캜 for 1 minute while maintaining the stretched state And immersed for 60 seconds in an aqueous solution at 28 DEG C in which the weight ratio of after-iodine / potassium iodide / distilled water was 0.05 / 5/100. Subsequently, the substrate was immersed in an aqueous 72 ° C aqueous solution having a weight ratio of potassium iodide / boric acid / distilled water of 8.5 / 8.5 / 100 for 300 seconds, washed with distilled water at 26 ° C for 20 seconds and then dried at 65 ° C for 10 minutes to obtain a polyvinyl alcohol film To prepare an iodine adsorbed polarizer. The water contact angle of the surface of the polarizer measured was 56 °.

Manufacturing example  2. Polarizer  Produce

A polarizer was prepared in the same manner as in Production Example 1, except that it was dried at 75 캜 in the drying process. The water contact angle of the measured polarizer surface was 58 °.

Manufacturing example  3. Polarizer  Produce

A polarizer was prepared in the same manner as in Production Example 1, except that it was dried at 85 캜 in the drying process. The water contact angle of the measured polarizer surface was 62 °.

Example  And Comparative Example

Plasma discharge treatment was performed on one surface of the polarizer using a plasma discharge treatment apparatus (PN-APP300TT, Mieikei Co., Ltd.).

The reaction gas was supplied to the pulsarama electrode portion at a flow rate of 10 L / min using a mixture of the acid anhydride and the remaining amount of nitrogen as shown in Table 1 below. An AC power source having a frequency of 20 kHz was used as the power source of the plasma generator, and a voltage of 8.5 kV was applied. The distance between the plasma electrodes was 2 mm and the discharge processing speed was 300 mm / sec.

Thereafter, a corona discharge treatment was performed on the surface of the stretched norbornene-based protective film (thickness 70 mu m) and the polymethylmethacrylate film (thickness 50 mu m) bonded to the polarizer.

Thereafter, the photo-curable adhesive composition was coated on the corona discharge treated surface of the drawn norbornene resin film to a thickness of 3 mu m with a bar coater, and the polarizer was bonded thereon.

A polymethylmethacrylate film was also coated with the photo-curable adhesive composition and bonded to the other side of the polarizer.

Thereafter, the laminate was irradiated with ultraviolet rays at a UVA standard integrated light quantity of 300 mJ / cm ² from one surface with an ultraviolet light irradiation device (Fusion Hose Fusion Hub) equipped with a belt conveyor to cure the adhesive composition, To prepare a polarizing plate.

The compositions and contents of the polarizer, the photo-curable adhesive composition and the acid anhydride used in the respective Examples and Comparative Examples are as shown in Table 1 below.

division Photo-curing adhesive composition Polarizer In gas
compound
(C) The photopolymerizable compound
(A) Photopolymerization initiator
(B) ingredient content
(Parts by weight) ingredient content
(Parts by weight) ingredient content
(volume%) Example 1 A-1 / A-2 47/50 B-1 3 Production Example 1 C-1 One Example 2 A-1 / A-2 47/50 B-1 3 Production Example 2 C-1 One Example 3 A-1 / A-2 47/50 B-1 3 Production Example 3 C-1 One Example 4 A-1 / A-2 47/50 B-1 3 Production Example 1 C-2 One Example 5 A-1 / A-2 47/50 B-1 3 Production Example 2 C-2 One Example 6 A-1 / A-2 47/50 B-1 3 Production Example 3 C-2 One Example 7 A-1 / A-2 47/50 B-1 3 Production Example 1 C-1 3 Example 8 A-1 / A-2 47/50 B-1 3 Production Example 1 C-1 5 Example 9 A-3 / A-4 45/50 B-2 5 Production Example 1 C-1 One Example 10 A-3 / A-4 45/50 B-2 5 Production Example 1 C-2 One Example 11 A-2 / A-4 48/47 B-1 / B-2 2/3 Production Example 1 C-1 One Example 12 A-1 / A-4 48/47 B-1 / B-2 2/3 Production Example 1 C-2 One Example 13 A-1 / A-2 47/50 B-1 3 Production Example 1 C-3 One Example 14 A-1 / A-2 47/50 B-1 3 Production Example 2 C-4 3 Example 15 A-1 / A-2 47/50 B-1 3 Production Example 1 C-5 One Example 16 A-1 / A-2 47/50 B-1 3 Production Example 2 C-1 /
C-6 1/1 Example 17 A-1 / A-2 47/50 B-1 3 Production Example 1 C-6 One Example 18 A-1 / A-2 47/50 B-1 3 Production Example 2 C-6 One Example 19 A-1 / A-2 47/50 B-1 3 Production Example 3 C-6 One Example 20 A-3 / A-4 45/50 B-2 5 Production Example 1 C-6 One Example 21 A-3 / A-4 45/50 B-2 5 Production Example 1 C-7 One Example 22 A-3 / A-4 45/50 B-2 5 Production Example 1 C-1 7 Comparative Example 1 A-1 / A-2 47/50 B-1 3 Production Example 1 - - Comparative Example 2 A-3 / A-4 45/50 B-2 5 Production Example 1 - - Comparative Example 3 A-3 / A-4 45/50 B-2 5 Production Example 2 - - Comparative Example 4 A-1 / A-2 47/50 B-1 3 Production Example 2 - - Comparative Example 5 A-1 / A-2 47/50 B-1 3 Production Example 3 - - A-1: phenoxyglycidyl ether
A-2: 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate
A-3: 4-hydroxybutyl acrylate
A-4: Dimethylaminoethyl acrylate
B-1: CPI-110A (Sanfrasa)
B-2: Irg184 (Ciba)
C-1: Maleic anhydride
C-2: Citraconic anhydride
C-3: 2H-Pyran-2,6 (3H) -dione
C-4: Diallyl pyrocarbonate
C-5: methyl acrylate
C-6: Acrylic acid
C-7: Allyl alcohol

Experimental Example

(1) Evaluation of adhesion

The polarizers prepared in Examples and Comparative Examples were allowed to stand at room temperature for 1 hour, and then the adhesiveness between the polarizer and the protective film was evaluated to such an extent that the blades were inserted when the blade of the cutter was pushed between the polarizer and the protective film.

◎: The cutter blade does not enter between the polarizer and the protective film.

○: The cutter blade enters 2 mm or less between the polarizer and the protective film

DELTA: The blade of the cutter enters between 2 mm and 5 mm or less between the polarizer and at least one protective film

X: The blade of the cutter enters the gap between the polarizer and at least one protective film without any difficulty

(2) Water temperature  evaluation

After leaving the polarizing plate prepared in the above Examples and Comparative Examples at 23 占 폚 and 55% relative humidity for 24 hours, a sample of 5 cm 占 2 cm was prepared with the absorption axis (stretching direction) as long sides. Then, the short sides of each sample were gripped, and 80% of the longitudinal direction was immersed in a water bath of 60 ° C for 4 hours, and then taken out to wipe out the water.

Since the polarizer shrinks due to immersion in hot water, the distance from the end of the protective film at the center of the short side of the sample to the shrunk polarizer was measured and made to be the shrink length.

In addition, since iodine eluted from the periphery of the polarizer due to hot water immersion and discolored, the distance from the end of the shrunk polarizer at the center of the short side of the sample to the uncolored portion was defined as the iodine dropout length.

The sum of the shrinkage length and the iodine dropout length was taken as the total erosion length. That is, the total erosion length is the distance from the end of the protective film at the center of the short side of the sample to the non-decolorized portion of the polarizer. The smaller the erosion length is, the better the water resistance is.

◎: total erosion length less than 2mm

○: total erosion length is 2 mm or more to less than 3 mm

△: total erosion length is 3 mm or more and less than 5 mm

X: Total erosion length is 5mm or more

(3) Peel force  evaluation

The polarizing plates prepared in Examples and Comparative Examples were allowed to stand at room temperature for 1 hour, and then bonded to a soda-lime glass with an acrylic pressure-sensitive adhesive. Thereafter, the autoclave was performed at a pressure of 2 atm, a temperature of 50 ° C, and a time of 20 minutes to remove bubbles generated during the bonding.

Soda glass / pressure-sensitive adhesive / corona treated norbornene resin film / monomer Plasma treated polarizer / corona treated polymethylmethacrylate resin In the film constitution, a norbornene-based COP film in the soda glass direction and a knife And 180 DEG peel force (measuring speed 300 mm / min) was measured on the adhesive layer surface when the polarizer was peeled off using an autograph

(4) Wet heat (85 [deg.] C, 85% RH ) After 120 hours Peel force

The peel strength after standing for 120 hours under the humid heat condition (85 DEG C, 85% RH) was evaluated.

The polarizing plates prepared in Examples and Comparative Examples were put into an oven with an anti-wet heat (85 ° C, 85% RH) and taken out after 120 hours, and a 180 ° peeling force (measuring speed 300 mm / min) was measured in the same manner as the peeling force evaluation method Respectively.

division Adhesiveness Water temperature Peel force (N / 25mm) After 120 hours of moist heat
Peel force (N / 25mm) Example 1 ◎ ○ 2.4 3.1 Example 2 ◎ ○ 2.3 2.9 Example 3 ◎ ○ 2.1 1.8 Example 4 ◎ ○ 2.3 2.9 Example 5 ◎ ○ 2.2 2.8 Example 6 ◎ ○ 2.1 2.0 Example 7 ◎ ◎ 3.1 3.5 Example 8 ◎ ◎ 3.8 4.2 Example 9 ◎ ○ 2.3 2.3 Example 10 ◎ ○ 2.2 2.2 Example 11 ◎ ○ 2.4 2.4 Example 12 ◎ ○ 2.4 2.3 Example 13 ◎ ○ 2.3 3.0 Example 14 ◎ ○ 1.8 2.1 Example 15 ◎ ○ 1.9 2.2 Example 16 ◎ ◎ 2.8 3.3 Example 17 ◎ ○ 1.9 2.1 Example 18 ◎ ○ 1.8 1.9 Example 19 ◎ ○ 1.8 1.8 Example 20 ◎ ○ 1.6 1.6 Example 21 ◎ ○ 1.6 1.6 Example 22 ◎ ○ 1.5 1.5 Comparative Example 1 ○ ○ 0.9 1.0 Comparative Example 2 ○ △ 0.7 0.1 Comparative Example 3 ○ △ 0.3 0.1 Comparative Example 4 ○ ○ 0.8 0.7 Comparative Example 5 △ △ 0.6 0.3

Referring to Table 2, the polarizing plates of Examples 1 to 21 were excellent in adhesive property and water resistance at room temperature. In addition, the peel strength was excellent, and the peel strength was also excellent even when it was left under the heat and humidity resistant condition.

In particular, it was confirmed that the polarizing plate treated with a gas containing a cyclic acid anhydride was very effective.

In Example 22, the gas contained an excessive amount of maleic anhydride, and the effect was somewhat lowered, but the effect was still excellent.

However, the polarizers of Comparative Examples 1 to 5 were poor in adhesiveness and water resistance at room temperature, and in particular, the peeling force in the case of being left under the peeling force and moisture-resistant condition was very low.

Claims (21)

A polarizer which has an unsaturated bond and is subjected to plasma discharge treatment with a gas containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group, and
And a protective film bonded to the processed surface of the polarizer with a photo-curable adhesive.
[Claim 2] The method according to claim 1, wherein the compound having a unsaturated bond and containing a hydroxyl group is selected from the group consisting of allyl alcohol, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl Wherein the polarizing plate is at least one selected from the group consisting of a polarizing plate and a polarizing plate.
The polarizing plate according to claim 1, wherein the compound having an unsaturated bond and containing a carboxyl group is at least one of (meth) acrylic acid and 2-carboxyethyl acrylate.
(Meth) acrylate, glycidyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate and the like. Wherein the polarizing plate is at least one selected from the group consisting of t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and propyl (meth) acrylate.
The polarizing plate according to claim 1, wherein the compound having an unsaturated bond and containing a hydroxyl group is diallyl polycarbonate.
The polarizing plate according to claim 1, wherein the compound having a unsaturated bond and containing a hydroxyl group is a cyclic acid anhydride.
7. The method of claim 6, wherein the cyclic acid anhydride is selected from the group consisting of maleic anhydride, citraconic anhydride, itaconic anhydride, 2-dodecene-1-ylsuccinic anhydride, 2H- (3H) -dione and 3-methylene dihydro-2H-pyran-2,6 (3H) -dione Wherein the polarizing plate is at least one selected from the group consisting of a polarizing plate and a polarizing plate.
The polarizer of claim 1, wherein the plasma-treated surface of the polarizer comprises a hydroxyl group or a carboxyl group.
[2] The polarizer of claim 1, wherein the polarizer is selected from the group consisting of a polyvinyl alcohol film, a dehydrated polyvinyl alcohol film, a dehydrochlorinated acid-treated polyvinyl alcohol film, a polyethylene terephthalate film, an ethylene-vinyl acetate copolymer film, , A cellulose film or a partially sapphire film thereof.
[2] The method according to claim 1, wherein the protective film is a polyester film, a cellulose film, a polycarbonate film, an acrylic film, a styrene film, a polyolefin film, a vinyl chloride film, a polyamide film, Based film, a polyether ketone-based film, a sulfide polyphenylene-based film, a vinyl alcohol-based film, a vinylidene chloride film, a vinyl butyral film, an allylate film, a polyoxymethylene film, a urethane film, In polarizing plate.
Subjecting at least one surface of the polarizer to a plasma discharge treatment with a gas having an unsaturated bond and containing a compound containing a hydroxyl group, a carboxyl group, an ester group or a hydroxyl group; And
Bonding the protective film to the processed surface of the polarizer with a photo-curable adhesive
Wherein the polarizing plate is a polarizing plate.
[Claim 12] The method according to claim 11, wherein the compound having a unsaturated bond and containing a hydroxyl group is selected from the group consisting of allyl alcohol, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) Wherein the polarizing plate is at least one selected from the group consisting of a polarizing plate and a polarizing plate.
[Claim 12] The method according to claim 11, wherein the compound having a unsaturated bond and containing a carboxyl group is at least one of (meth) acrylic acid and 2-carboxyethyl acrylate.
(Meth) acrylate, glycidyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, Wherein the polarizing plate is at least one selected from the group consisting of acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and propyl (meth) acrylate.
The method for producing a polarizing plate according to claim 11, wherein the compound having an unsaturated bond and containing a hydroxyl group is diallyl polycarbonate.
The method for producing a polarizing plate according to claim 11, wherein the compound having an unsaturated bond and containing a hydroxyl group is a cyclic acid anhydride.
16. The method of claim 16, wherein the cyclic acid anhydride is selected from the group consisting of maleic anhydride, citraconic anhydride, itaconic anhydride, 2-dodecene-1-ylsuccinic anhydride, 2H- (3H) -dione and 3-methylene dihydro-2H-pyran-2,6 (3H) -dione Wherein the polarizing plate is at least one selected from the group consisting of a polarizing plate and a polarizing plate.
12. The method of claim 11, wherein the compound is comprised between 1 and 5% by volume of the total gas volume.
12. The method of manufacturing a polarizing plate according to claim 11, wherein the applied voltage for the plasma discharge treatment is 1 to 10 kV.
12. The method of manufacturing a polarizing plate according to claim 11, wherein the operating frequency of the power source of the plasma discharge processing apparatus is 1 KHz to 150 MHz.
12. The method of manufacturing a polarizing plate according to claim 11, wherein the inter-electrode distance of the plasma discharge processing apparatus is 0.5 to 50 mm.