KR20180086138A - Polarizing plate - Google Patents

Abstract

The present invention provides an optical member having a surface protection film for a polarizing plate which uses a polarizing plate having a surface protection film for a polarizing plate having a specific configuration (laminating order) to prevent whitening or tag destruction of a panel of a liquid crystal display (LCD) or the like when peeling the surface protection film for a polarizing plate after laminating (affixing) the polarizing plate on the liquid crystal display or the like to use the polarizing plate, and has excellent peeling electrification prevention, contamination resistance, and durability. The polarizing plate having a surface protection film includes: a polarizer; a surface protection film for a polarizing plate on at least one surface of the polarizer; and an antistatic layer formed on an opposite side of the surface coming in contact with the polarizer of the surface protection film for a polarizing plate by an antistatic composition including a conductive polymer. The polarizing plate having a surface protection film for a polarizing plate includes: a base film; an adhesive layer on one surface of the base film; and a surface protection film for a polarizing plate having an antistatic layer on an opposite side of the surface coming in contact with the adhesive layer of the base film. The adhesive layer of the surface protection film for a polarizing plate is arranged to laminate the surface protection film for a polarizing plate on the antistatic layer of the polarizing plate.

Description

POLARIZING PLATE

The present invention relates to a polarizing plate having a surface protective film for a polarizing plate. Particularly, the polarizing plate having the above-mentioned surface protective film can form an image display device such as a liquid crystal display (LCD), an organic EL display, a CRT, or a PDP as an optical film alone or as an optical film laminated thereon.

In a liquid crystal display device, an organic EL display device, or the like, it is indispensable to arrange a polarizer in a liquid crystal cell in the liquid crystal display device, for example, from the image forming system thereof, and a polarizing plate is generally adhered.

For example, in the production of a liquid crystal display panel, a polarizing plate bonded to a liquid crystal cell has a pressure-sensitive adhesive layer constituting a surface protective film for a polarizing plate in order to prevent occurrence of scratches and contamination during processing, To the surface of the polarizing plate. However, the surface protective film is peeled off when it becomes unnecessary, which causes static electricity to be generated when peeling off, resulting in whitening on the liquid crystal panel, or destruction of the tag.

In order to suppress the generation of such static electricity, an antistatic agent such as an alkali metal salt is mixed with the pressure-sensitive adhesive layer to give antistatic properties (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2009-251281

However, when an antistatic agent is added to the pressure-sensitive adhesive layer as in Patent Document 1, the adhesive force based on the pressure-sensitive adhesive layer becomes insufficient, or the antistatic agent bleeds out to contaminate the surface of the polarizing plate. It is difficult to achieve compatibility.

Further, in the polarizing plate after peeling the surface protective film for polarizing plate, problems such as scratches may occur in subsequent steps, and durability such as scratch resistance is required.

Therefore, the present invention has been made in view of the above circumstances, and as a result, it has been found that by using a polarizing plate (polarizing plate) having a surface protective film for a polarizing plate having a specific constitution (in order of lamination), the polarizing plate is laminated When the surface protective film for polarizing plate is peeled off after use, it is possible to prevent the whitening of the panel or the tag of the panel such as the liquid crystal display device and to provide a surface protective film for polarizing plate excellent in peeling electrification preventing property and excellent in stain resistance and durability And an optical member having an optical axis.

That is, a polarizing plate having a surface protective film of the present invention is a polarizing plate having a polarizer and a polarizer protective film on at least one side of the polarizer, wherein the polarizer protective film comprises a conductive polymer- A surface protective film for a polarizing plate having an antistatic layer on the opposite side of a surface of the base film which is in contact with the pressure sensitive adhesive layer, Wherein the surface protective film for the polarizing plate is laminated on the antistatic layer of the polarizing plate via the pressure-sensitive adhesive layer of the surface protective film for the polarizing plate, and the pressure-sensitive adhesive composition for forming the pressure- Is not contained.

In the polarizing plate having a surface protective film of the present invention, it is preferable that the protective film for a polarizer is at least one kind selected from the group consisting of a (meth) acrylic resin, a cyclic olefin resin, a polyester resin and a polycarbonate resin It is preferably formed by a resin.

In the polarizing plate having the surface protective film of the present invention, it is preferable that the polarizing protective film has an ultraviolet absorbing function.

A polarizing plate having a surface protective film for a polarizing plate of the present invention is characterized by including a surface protective film for a polarizing plate having an antistatic layer, a base film and a pressure sensitive adhesive layer formed by a pressure sensitive adhesive composition containing no antistatic component, An antistatic layer formed by an antistatic agent composition, a protective film for a polarizer, and a polarizer, and laminated on the antistatic layer of the polarizing plate via a pressure-sensitive adhesive layer of the surface protective film for the polarizer, (A polarizing plate) having a surface protective film for a polarizing plate, and the surface protective film for a polarizing plate is peeled off after the polarizing plate is laminated (adhered) to a liquid crystal display The antistatic layer constituting the polarizing plate and the antistatic layer constituting the polarizing plate are in a specific position (in the order of lamination) When it is possible to prevent the destruction of the bleaching or tag of a panel such as a device, it is useful to excellent anti-peeling electrification. In addition, since the antistatic component is not contained (substantially) in the pressure-sensitive adhesive layer, contamination due to the antistatic component in the pressure-sensitive adhesive layer can be prevented and the antistatic property of the antistatic layer of the pressure- It is possible to provide an optical member having a surface protective film for a polarizing plate which is also excellent in flexibility and durability (scratch resistance).

1 is a schematic cross-sectional view showing an example of a polarizing plate having a surface protective film for a polarizing plate according to the present invention.
2 is a schematic cross-sectional view showing an example of the configuration of a polarizing plate having a surface protective film for a polarizing plate according to the present invention.
3 is an explanatory view showing a method of measuring the peeling electrification voltage.

Hereinafter, embodiments of the present invention will be described in detail.

<Overall Structure of Polarizer Having Surface Protective Film for Polarizer>

1, the polarizing plate surface protective film 2 is a polarizing plate having a surface protective film for a polarizing plate disclosed in JP-A- And the antistatic layer 10 is laminated on one side of the polarizing plate 3. The polarizing plate 3 has a polarizer 22 and a protective film 21 for polarizer which are in contact with at least one surface of the polarizer 22 and a polarizer of the protective film 21 for polarizer And an antistatic layer 20 laminated on the surface opposite to the surface. The polarizing plate surface protective film may be a polarizing plate 1 having a surface protective film for polarizing plate which is directly laminated (contacted) with the antistatic layer 20 of the polarizing plate 3 via the pressure-sensitive adhesive layer 20 . The polarizing plate having the surface protective film for a polarizing plate described herein may be either a roll type or a leaf type.

&Lt; Base film of surface protective film for polarizing plate &

The surface protective film for a polarizing plate used in the present invention is characterized by having a base film and an antistatic layer on one side of the base film opposite to the side in contact with the pressure sensitive adhesive layer of the base film. In the techniques disclosed herein, the resin material constituting the base film can be used without particular limitation, and examples thereof include resins having excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, flexibility and dimensional stability Is preferably used. In particular, since the base film has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like, and it can be wound in a roll form, which is useful.

As the base film (substrate, support), for example, a polyester resin, a cellulose polymer, a polycarbonate polymer, an acrylic polymer and the like are mixed with a main resin component (main component in a resin component, typically 50% ) As the base film can be preferably used as the base film. Or a base film composed of two or more kinds of blends of these polymers.

Various additives such as antioxidants, ultraviolet absorbers, plasticizers, colorants (pigments, dyes, etc.) may be added to the resin material constituting the substrate film if necessary. For example, known or conventional surface treatments such as corona discharge treatment, plasma treatment, ultraviolet ray irradiation treatment, acid treatment, alkali treatment, and application of a primer may be performed. Such a surface treatment may be, for example, a treatment for enhancing the adhesion (adhesion property of the pressure-sensitive adhesive layer) between the base film and the pressure-sensitive adhesive layer.

The surface protective film for a polarizing plate used in the present invention may be a plastic film formed by an antistatic treatment as the base film. Use of the base film is preferable because the surface protective film for a polarizing plate itself can be prevented from being charged during peeling. In addition, when the base film is a plastic film and the antistatic treatment is applied to the plastic film, it is possible to reduce the electrification of the surface protective film per se for the polarizing plate itself and to obtain an electrification preventing performance against the adherend. The method for imparting the antistatic function is not particularly limited and conventionally known methods can be used. For example, an antistatic resin and a conductive polymer composed of an antistatic agent and a resin component, a conductive polymer containing a conductive material, A method of depositing or plating a conductive material, a method of kneading an antistatic agent, and the like.

The thickness of the base film is 50 占 퐉 or more, preferably 50 to 200 占 퐉, more preferably 70 to 150 占 퐉, and further preferably 75 to 130 占 퐉. When the thickness of the base film is within the above range, bonding workability when bonding the surface protective film for polarizing plate to the polarizing plate and transportability after bonding are favorable.

<Pressure-sensitive adhesive layer of surface protective film for polarizing plate>

The pressure-sensitive adhesive layer constituting the surface protective film for a polarizing plate used in the present invention is formed by a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition does not contain an antistatic component. The pressure-sensitive adhesive composition contains a pressure-sensitive adhesive polymer, and the pressure-sensitive adhesive polymer can be used without particular limitation as long as it has stickiness. Examples of the pressure sensitive adhesive composition include acrylic pressure sensitive adhesives containing a (meth) acrylic polymer, urethane pressure sensitive adhesives containing a urethane polymer, and silicone pressure sensitive adhesives containing a silicone polymer. Particularly in view of adhesiveness and transparency, ) It is particularly preferable to use an acrylic pressure-sensitive adhesive containing an acrylic polymer.

In the pressure-sensitive adhesive layer used in the present invention, the pressure-sensitive adhesive composition preferably contains a crosslinking agent. Further, in the present invention, the pressure-sensitive adhesive composition may be used to form a pressure-sensitive adhesive layer. For example, when the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive containing the (meth) acrylic polymer, by appropriately controlling and crosslinking the constituent units, the constituent ratio, the selection and the addition ratio of the (meth) acrylic polymer, This excellent pressure-sensitive adhesive layer (surface protective film for polarizing plate) can be obtained.

As the crosslinking agent, an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative and a metal chelate compound may be used, and in particular, the use of an isocyanate compound is a preferable form. These compounds may be used alone or in combination of two or more.

Further, the pressure-sensitive adhesive composition may contain other known additives such as a crosslinking catalyst, a lubricant, a powder such as a colorant, a pigment, a plasticizer, a tackifier, a low molecular weight polymer, a surface lubricant, a leveling agent, , A corrosion inhibitor, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, a silane coupling agent, an inorganic or organic filler, a metal powder, a particulate, a foaming agent and the like.

Also, the pressure-sensitive adhesive composition is characterized in that it does not contain an antistatic component. The term &quot; not containing an antistatic component &quot; means that the pressure-sensitive adhesive layer contains substantially no antistatic agent, The surface resistance value of the surface of the pressure-sensitive adhesive layer is 10 &lt; ¹³ &gt; or more). When the pressure-sensitive adhesive composition contains an antistatic component, contamination usually occurs due to transfer of the antistatic component from the pressure-sensitive adhesive layer. However, the pressure-sensitive adhesive layer used in the present invention is a layer in which the pressure- This contamination can be prevented by not including it, and it is excellent in stain resistance and becomes a preferable form.

&Lt; Antistatic layer of surface protective film for polarizing plate >

The surface protective film for a polarizing plate used in the present invention is characterized by having a base film and an antistatic layer on one side of the substrate film opposite to the side in contact with the pressure sensitive adhesive layer on one side of the base film. By providing an antistatic layer on the outermost layer (back surface of the base film) of the surface protective film for a polarizing plate, a grounding effect is exhibited, which is excellent in peeling electrification prevention property.

In order to form the antistatic layer, it is preferable that antistatic treatment is performed on the base film. As the antistatic treatment, a general antistatic treatment method can be used and is not particularly limited. For example, a method of providing an antistatic layer on the back surface of the substrate film (the surface opposite to the pressure-sensitive adhesive layer) or the like can be used.

Examples of the method of providing the antistatic layer include an antistatic agent or an antistatic resin containing an antistatic agent and a resin component; a method of applying a conductive resin composition containing a conductive material and a resin component or a conductive polymer to a base film; Or a method of vapor-depositing or plating them.

Examples of the antistatic agent include a cationic antistatic agent having a cationic functional group (e.g., a primary amino group, a secondary amino group, a tertiary amino group, etc.) such as a quaternary ammonium salt or a pyridinium salt; Anionic antistatic agents having anionic functional groups such as sulfonic acid salts, sulfuric acid ester salts, phosphonic acid salts and phosphoric acid ester salts; Amphoteric antistatic agents such as alkyl betaines and derivatives thereof, imidazolines and derivatives thereof, alanines and derivatives thereof; Nonionic type antistatic agents such as amino alcohols and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof; Furthermore, an ion-conductive polymer obtained by polymerizing or copolymerizing a monomer having an ion-conductive group represented by the cationic antistatic agent, the anionic antistatic agent and the positive ionic antistatic agent can be mentioned.

Specifically, examples of the cationic antistatic agent include cationic antistatic agents having a quaternary ammonium group such as alkyltrimethylammonium salt, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salt, acyl chloride choline, and polydimethylaminoethyl methacrylate. (Meth) acrylate copolymers, styrenic copolymers having quaternary ammonium groups such as polyvinylbenzyltrimethylammonium chloride, and diallylamine copolymers having quaternary ammonium groups such as polydiallyldimethylammonium chloride. Examples of the anion-type antistatic agent include alkylsulfonic acid salts, alkylbenzenesulfonic acid salts, alkylsulfuric acid ester salts, alkyl ethoxy sulfuric acid ester salts, alkyl phosphoric acid ester salts and sulfonic acid group-containing styrene copolymers. Examples of the positive ion type antistatic agent include alkyl betaine, alkyl imidazolium betaine, and carbobetaine graft copolymer. Examples of the nonionic antistatic agent include fatty acid alkylolamides, di- (2-hydroxyethyl) alkylamines, polyoxyethylene alkylamines, fatty acid glycerin esters, polyoxyethylene glycol fatty acid esters, sorbitan fatty acid esters, Polyoxyethylene alkyl ethers, polyethylene glycols, polyoxyethylenediamines, polyethers, copolymers composed of polyesters and polyamides, methoxypolyethylene glycol (meth) acrylates, and the like. .

Examples of the conductive polymer include polyaniline, polypyrrole, and polythiophene.

Examples of the conductive material include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, copper iodide, And alloys or mixtures thereof.

As the resin component, a general-purpose resin such as polyester, acrylic, polyvinyl, urethane, melamine, and epoxy is used. When the antistatic agent is a polymer-type antistatic agent, the resin component may not be contained in the antistatic resin. The antistatic resin may also contain a compound such as a melamine-based, urea-based, glyoxal-based or acrylamide-based compound, an epoxy based compound or an isocyanate based compound which is methylol or alkylol as a crosslinking agent.

Examples of the method of forming the antistatic layer by application include a method of diluting the antistatic resin, the conductive polymer and the conductive resin composition with a solvent or a dispersion medium such as an organic solvent or water, applying the coating liquid to the substrate film, . Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol and isopropanol. These can be used singly or in combination. As a coating method, a known coating method is used. Specifically, a roll coating, a gravure coating, a reverse coating, a roll brush, a spray coating, an air knife coating, an impregnation and a curtain coating can be mentioned.

The thickness of the antistatic layer (antistatic resin layer, conductive polymer layer, conductive resin composition layer) formed by the application is preferably 0.001 to 5 mu m, more preferably 0.005 to 1 mu m.

Examples of the method for depositing or plating the conductive material include vacuum deposition, sputtering, ion plating, chemical vapor deposition, spray pyrolysis, chemical plating, and electroplating.

The thickness of the antistatic layer (conductive material layer) formed by the deposition or plating is preferably 20 to 10000 Å (0.002 to 1 탆), and more preferably 50 to 5000 Å (0.005 to 0.5 탆).

<Surface Protective Film for Polarizing Plate>

The surface protective film for a polarizing plate used in the present invention is characterized by having a base film and an antistatic layer on one side of the base film opposite to the side in contact with the pressure sensitive adhesive layer, The pressure-sensitive adhesive layer is formed by crosslinking the pressure-sensitive adhesive composition after the application of the pressure-sensitive adhesive composition, but it is also possible to transfer the pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition after crosslinking to a base film or the like.

The method for forming the pressure-sensitive adhesive layer on the base film is not particularly limited. For example, the pressure-sensitive adhesive composition (solution) is coated on the base film and the pressure-sensitive adhesive layer is formed on the base film by drying and removing the polymerization solvent . Thereafter, curing may be performed for the purpose of adjusting the component migration of the pressure-sensitive adhesive layer and adjusting the crosslinking reaction. When the pressure-sensitive adhesive composition is applied onto a base film to produce a surface protective film for a polarizing plate, at least one solvent other than the polymerization solvent may be newly added to the pressure-sensitive adhesive composition so as to be uniformly applied on the base film.

As a method for forming a pressure-sensitive adhesive layer in the production of the surface protective film for a polarizing plate used in the present invention, a known method used for production of pressure-sensitive adhesive tapes is used. Specific examples include an extrusion coating method using a roll coat, a gravure coat, a reverse coat, a roll brush, a spray coat, an air knife coating method, a die coater, or the like.

The surface protective film for a polarizing plate used in the present invention is usually produced so that the thickness of the pressure sensitive adhesive layer is about 3 to 100 탆, preferably about 5 to 50 탆. When the thickness of the pressure-sensitive adhesive layer is within the above-mentioned range, it is preferable that a proper balance of re-peeling property and adhesiveness can be easily obtained.

The total thickness of the surface protective film for a polarizing plate used in the present invention is preferably 5 to 300 占 퐉, more preferably 10 to 200 占 퐉, and most preferably 12 to 100 占 퐉. Within the above-mentioned range, it is preferable because it is excellent in adhesive property (re-release property, adhesiveness, etc.), workability, and appearance. The total thickness means a total thickness including all layers such as a base film, a pressure-sensitive adhesive layer, an antistatic layer, and other layers.

The surface protective film for a polarizing plate disclosed herein may be embodied in a form further comprising another layer in addition to the base film, the pressure-sensitive adhesive layer and the antistatic layer. Examples of the other layer include an undercoating layer (anchor layer) for enhancing the transparency of the antistatic layer and the pressure-sensitive adhesive layer.

<Polarizer>

The polarizing plate used in the present invention is formed by an antistatic agent composition comprising a polarizer and a protective film for a polarizer on at least one side of the polarizer and on the side opposite to the side of the polarizing protective film in contact with the polarizer, And an antistatic layer formed on the substrate. (For example, a phase difference film or a liquid crystal display device) may be provided on the surface of the pressure-sensitive adhesive layer opposite to the surface in contact with the polarizing plate, And the like can be stacked. An antistatic layer positioned on the surface layer of the polarizing plate and a pressure-sensitive adhesive layer constituting the surface protective film for the polarizing plate are directly laminated (in contact with each other).

<Polarizer>

As the polarizer used in the present invention, a polyvinyl alcohol-based resin is used. As the polarizer, a dichromatic material such as iodine or a dichroic dye is adsorbed on a hydrophilic polymer film such as a polyvinyl alcohol film, a partially porous polyvinyl alcohol film or an ethylene / vinyl acetate copolymerization system partial saponification film, Stretched polyvinyl alcohol films, stretched polyvinyl alcohol films, polyvinyl alcohol dehydrated films, polyvinyl chloride dehydrochlorinated films, and the like. Among them, a polyvinyl alcohol film and a polarizer made of a dichromatic material such as iodine are suitable.

The polarizer obtained by dyeing the polyvinyl alcohol-based film with iodine and uniaxially stretching can be produced, for example, by dying polyvinyl alcohol in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride or the like, and may be immersed in an aqueous solution such as potassium iodide. If necessary, the polyvinyl alcohol film may be dipped in water and washed with water before dyeing. By washing the polyvinyl alcohol film with water, it is possible not only to clean the surface of the polyvinyl alcohol film surface and the antiblocking agent but also to swell the polyvinyl alcohol film to prevent unevenness such as uneven dyeing. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching, followed by dyeing with iodine. It can be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Though the thickness of the polarizer can be suitably determined, it is preferably 30 占 퐉 or less, more preferably 28 占 퐉 or less, further preferably 5-25 占 퐉. Such a polarizer is excellent in durability against thermal shock because it has less thickness unevenness, is excellent in thin layer properties and visibility, and has small dimensional change.

The polarizer is characterized in that the optical characteristics exhibited by the simple transmittance T and the polarization degree P satisfy the following formula: P> - (100.929T-42.4-1) x 100 (where T <42.3) or P≥99.9 ) Is satisfied. The polarizer configured to satisfy the above conditions uniquely has the performance required as a liquid crystal TV display using a large display element. Specifically, it has a contrast ratio of 1000: 1 or more and a maximum luminance of 500 cd / m 2 or more. As another use, for example, it is bonded to the viewer side of the organic EL cell.

<Protective Film for Polarizer>

The material constituting the protective film for a polarizer is not particularly limited, but a polymer (resin) excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, ultraviolet ray absorbability and the like is preferable. (Meth) acrylic polymer} such as polyethylene terephthalate and polyethylene naphthalate (polyester resin) such as polyethylene terephthalate and polyethylene naphthalate, (meth) acrylic polymer such as polymethyl methacrylate}, polycarbonate polymer ( Polycarbonate resin) and the like. Polyolefins (cyclic olefin resins) having polyethylene or polypropylene, cyclo-based or norbornene structure, and the like are also examples of polymers forming the protective film for polarizer. Among them, the polarizer protective film is preferably formed of at least one resin selected from the group consisting of a (meth) acrylic resin, a cyclic olefin resin, a polyester resin and a polycarbonate resin, It is particularly preferable to use a resin having an ultraviolet ray absorbing function. These protective films for polarizers are usually bonded to polarizers by an adhesive layer.

The protective film for a polarizer may contain one or more optional additives. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, coloring inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants and the like. The content of the polymer in the protective film for a polarizer is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, particularly preferably 70 to 97% by weight . When the content of the polymer in the protective film for a polarizer is 50% by weight or less, there is a possibility that the transparency and the like inherently possessed by the polymer can not be sufficiently expressed.

The thickness of the protective film for a polarizer can be suitably determined, but is generally 100 탆 or less, more preferably 80 탆 or less, further preferably 80 탆 or less from the viewpoints of workability such as strength and handling properties, 10 to 60 mu m is preferable.

A functional layer such as a hard coat layer, an antireflection layer, an anti-sticking layer, a diffusion layer, or an anti-glare layer may be provided on the surface of the polarizing protective film on which the polarizer is not adhered. The functional layers such as the hard coat layer, the antireflection layer, the anti-sticking layer, the diffusion layer and the anti-glare layer can be provided on the protective film for the polarizer itself or separately from the protective film for the polarizer .

Further, in the lamination of the polarizer and the polarizer protective film, an easy adhesion layer can be provided between the polarizer protective film and the adhesive layer.

<Antistatic Layer of Polarizer>

A polarizing plate having a surface protective film for a polarizing plate according to the present invention is a polarizing plate having a polarizer and a polarizer protective film on at least one surface of the polarizer, Wherein the surface protective film for polarizing plate is laminated on the antistatic layer of the polarizing plate via the pressure-sensitive adhesive layer of the surface protective film for polarizing plate, wherein the antistatic layer has an antistatic layer formed by the antistatic composition. Since the antistatic layer is an antistatic layer formed of an antistatic composition containing a conductive polymer, an increase in surface resistance can be suppressed even in a high-temperature environment, and an antistatic layer excellent in flexibility and durability can be obtained and a preferable form is obtained.

Further, by providing an antistatic layer on the surface of the polarizing plate, it is not necessary to impart antistatic properties to the pressure-sensitive adhesive layer constituting the surface protective film for polarizing plate which is directly laminated (contacted) with the antistatic layer, It is preferable that it is excellent in stain resistance and appearance. Particularly, by combining the polyaniline sulfonic acid and the polythiophene doped with the polyanion, within the above range, the polyaniline sulfonic acid alone or the polythiophene doped with the polyanion may be added alone The reason why the stability of the antistatic property under a high temperature environment is improved as compared with the case is presumed as follows. The polythiophenes doped with polyanions have a structure in which the polythiophenes form a complex for the anion group of the polyanion, and the conductive mechanism thereof is not limited to the intramolecular challenge of polythiophenes occurring in the complex, The challenge between the intermolecular challenges of thiophenes and the complex structure is known. Here, the challenge between complex structures is a rate-limiting process because the intermolecular distance is small. By using polyaniline sulfonic acid, which is a polymer higher than polythiophenes, in combination, polyaniline sulfonic acid bonds between composites composed of polythiophenes and polyanions and has conductivity itself, so that the conductivity between the composites is enhanced, and the antistatic property is improved, It is presumed that the stability under the environment is increased, and it becomes very useful as a polarizing plate. When the above-mentioned polyaniline sulfonic acid is used alone as the conductive polymer, the initial conductivity is low, so that the peeling electrification voltage and the surface resistance value are likely to increase with time.

When the polythiophenes doped with the polyanions are used alone, the initial conductivity is high, but the polyanion (corresponding to the dopant) is more likely to be desorbed than the polythiophene with the elapse of time, An increase in voltage, surface resistance, or the like tends to occur.

&Lt; Conductive polymer &

It is preferable that the antistatic layer is formed of an antistatic agent composition containing polythiophenes doped with polyaniline sulfonic acid and polyanion as a conductive polymer component. By the combination of the conductive polymers, the polyaniline sulfonic acid is responsible for the conductivity between the core shell structure of the polythiophene / polyanion type, compared with the case where the conductive polymer is used alone, so that the conductivity is increased and the peeling electrification prevention And antistatic property in a high temperature environment can be stabilized and useful.

The content of the conductive polymer is preferably from 1 to 90% by weight, more preferably from 5 to 80% by weight, still more preferably from 10 to 70% by weight based on the total components contained in the antistatic layer, Is 20 to 50% by weight. If the content of the conductive polymer is too small, the antistatic effect tends to be small. If the content of the conductive polymer is too large, there is a fear that the adhesion of the antistatic layer to the base material (protective film for polarizer) Which is undesirable.

The polyaniline sulfonic acid used as the conductive polymer component preferably has a weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography (GPC) of 5 x 10 ⁵ or less, more preferably 3 x 10 ⁵ or less Do. The weight average molecular weight of these conductive polymers is preferably 1 x 10 ³ or more, and more preferably 5 x 10 ³ or more.

As a commercially available product of the above-mentioned polyaniline sulfonic acid, trade name "aqua-PASS" manufactured by Mitsubishi Rayon Co., Ltd. and the like are exemplified.

Examples of the polythiophenes used as the conductive polymer component include polythiophenes such as polythiophene, poly (3-methylthiophene), poly (3-ethylthiophene) (3-hexylthiophene), poly (3-decylthiophene), poly (3-decylthiophene) , Poly (3-chlorothiophene), poly (3-cyanothiophene), poly (3-bromothiophene) (3-hydroxythiophene), poly (3-methoxythiophene), poly (3,4-dimethylthiophene) (3-heptyloxythiophene), poly (3-octylthiophene), poly (3-butoxythiophene) (3-octadecyloxythiophene), poly (3,4-dihydroxythiophene), poly (3,4-dimethoxyphene) Poly (3,4-dibutoxy thiophene), poly (3,4-diethoxythiophene), poly Poly (3,4-dioctyloxythiophene), poly (3,4-dideoxylthiophene), poly (3,4-dioctyloxythiophene) , Poly (3,4-ethylenedioxythiophene), poly (3,4-propylene dioxythiophene), poly (3,4-butenedioxythiophene) (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxyethylthiophene) Poly (3-methyl-4-carboxybutylthiophene). These may be used singly or in combination of two or more. Among them, poly (3,4-ethylenedioxythiophene) (PEDOT) is preferable from the viewpoint of conductivity.

The degree of polymerization of the polythiophenes is preferably 2 to 1000, and more preferably 5 to 100. If it is within the above range, it is preferable since conductivity is excellent.

The polyanion is a polymer of a constituent unit having an anionic group and acts as a dopant for the polythiophenes. Examples of the polyanions include polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallylsulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly (2-acrylamido-2-methylpropanesulfonic acid), polyisoprenesulfonic acid, (Meth) acrylate, methacrylate, poly (4-sulfobutyl methacrylate), polymethallyloxybenzenesulfonic acid, polyvinylcarboxylic acid, polystyrenecarboxylic acid, polyallylcarboxylic acid, polyacrylic carboxylic acid, Acid, poly (2-acrylamido-2-methylpropanecarboxylic acid), polyisoprenecarboxylic acid, polyacrylic acid, and polysulfonated phenylacetylene. These homopolymers may be used or two or more copolymers may be used. Of these, polystyrene sulfonic acid (PSS) is preferred.

The polyanions have a weight average molecular weight (Mw) of preferably 1,000 to 1,000,000, and more preferably 2,000 to 500,000. Within this range, the polythiophene is preferred because it is excellent in doping and dispersibility.

Examples of commercially available products of polythiophenes doped with the polyanion include poly (3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (PEDOT / PSS), trade name "Bytron P" Trade name &quot; Denatron P-502RG &quot; manufactured by Nagase Chemtex Co., Ltd., and the like. In particular, when PEDOT / PSS is used as the antistatic layer constituting the polarizing plate, the occurrence of contamination is suppressed and the stain resistance is excellent compared with the case of using the antistatic component in the pressure-sensitive adhesive layer constituting the surface protective film for polarizing plate, / PSS is a conductive polymer, an antistatic layer having excellent flexibility and durability can be obtained and a preferable form is obtained.

The antistatic agent composition may be prepared by mixing the polyaniline sulfonic acid and the polythiophenes doped with the polyaniline (weight ratio) (polyaniline sulfonic acid: polythiophenes doped with the polyanions) to 90 : 10 to 10:90, more preferably 85:15 to 15:85, and even more preferably 80:20 to 20:80. Within this range, the surface resistance value can be suppressed to a low level, and particularly, the surface resistance value stability under a high temperature environment is excellent, which is a preferable form. When the content of the polyaniline sulfonic acid is small or the content of the polythiophene doped with the polyanion is small, the surface resistance value under a high temperature environment tends to rise, which is not preferable.

<Binder>

The antistatic layer may contain a binder component and may be used without any particular limitation, but it is formed by an antistatic agent composition containing a polyester resin as a binder in order to impart a solvent resistance, a mechanical strength, a charging property and a thermal stability desirable. The polyester resin is preferably a resin material containing a polyester as a main component (typically, more than 50 wt%, preferably 75 wt% or more, for example, 90 wt% or more). The polyester is typically prepared from polyvalent carboxylic acids (typically dicarboxylic acids) having two or more carboxyl groups in one molecule and derivatives thereof (anhydrides, esters, halides, etc. of the polyvalent carboxylic acids) One or two or more compounds selected from one or more compounds (polyvalent carboxylic acid component) selected from polyvalent alcohols (typically, diols) having at least two hydroxyl groups in one molecule And a polyhydric alcohol component) condensed with each other.

Examples of compounds usable as the polyvalent carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±) But are not limited to, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, Methyl adipic acid, dimethyadipic acid, tetramethyladipic acid, methylene adipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6- Aliphatic dicarboxylic acids such as tetramethylsuburic acid, azelaic acid, sebacic acid, perfluorosevacic acid, brassylic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid and tetradecyldicarboxylic acid; Cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4- (2-norbornene) dicarboxylic acid, 5- Alicyclic dicarboxylic acids such as norbornene-2,3-dicarboxylic acid (hydamic acid), adamantanedicarboxylic acid and spiroheptanedicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, methyl There may be mentioned, for example, acid anhydrides such as isophthalic acid, dimethyl isophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethyl terephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalene dicarboxylic acid, oxofluorene dicarboxylic acid, Biphenyl dicarboxylic acid, biphenylene dicarboxylic acid, dimethyl biphenylene dicarboxylic acid, 4,4'-p-terphenylenedicarboxylic acid, 4,4'-p-crown Benzene dicarboxylic acid, azobenzene dicarboxylic acid, homophthalic acid, phenylene diacetic acid, 4,4'- (methylene di-p-biphenylene) dipropionic acid, 4, 4 '- (methylene di-p-biphenylene) dicarboxylic acid, naphthalene dicarboxylic acid, naphthalene diphopropionic acid, biphenyl diacetic acid, Aromatic dicarboxylic acids such as 4'-bibenzyl diacetic acid, 3,3 '(4,4'-bibenzyl) dipropionic acid, and oxydi-p-phenylene diacetic acid; (For example, an alkyl ester, a monoester, a diester, etc.) of any of the above-described polyvalent carboxylic acids, an acid halide corresponding to any of the polyvalent carboxylic acids described above (for example, dicarboxylic acid chloride ); And the like.

 Preferable examples of the compounds usable as the polyvalent carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid, and acid anhydrides thereof; Aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, hy- phamic acid and 1,4-cyclohexanedicarboxylic acid, and acid anhydrides thereof; And lower alkyl esters of the dicarboxylic acids (for example, esters with monoalcohols having 1 to 3 carbon atoms).

Examples of the compound that can be employed as the polyhydric alcohol component include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, Methyl-1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, Diols such as 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A, . Other examples include alkylene oxide adducts of these compounds (e.g., ethylene oxide adduct, propylene oxide adduct, etc.).

The molecular weight of the polyester resin is a number average molecular weight (Mn) in terms of standard polystyrene measured by gel permeation chromatography (GPC), for example, about 5 × 10 ³ to 1.5 × 10 ⁵ (preferably 1 × 10 ⁴ to 6 x 10 ⁴ ). The glass transition temperature (Tg) of the polyester resin may be, for example, from 0 to 120 캜 (preferably from 10 to 80 캜).

Examples of commercially available products of the above polyester resins include Vylon MD-1100, MD-1200, MD-1245, MD-1335, MD-1480, MD-1500, MD-1930, MD-1985 , Plascoat Z-221, Z-446, Z-561, Z-565, Z-880, Z-3310, RZ-105, RZ-570 and Z-730 manufactured by Kokugaku Kogyo Co., A-110, A-120, A-124GP, A-125S, A-160P, A-520, A-520 manufactured by Takamatsu Yushi Co., Ltd., Z-760, Z-592, Z- 613D, A-615GE, A-640, A-645GH, A-647GEX, A-680, A-684G, WAC-14 and WAC-17XC.

The antistatic layer may contain a resin other than a polyester resin (for example, an acrylic resin, an acryl-urethane resin, an acrylic-urethane resin, or a polyimide resin) as a binder so long as it does not significantly impair the performance (for example, One or more resins selected from acrylic-styrene resin, acrylic-silicone resin, silicone resin, polysilazane resin, fluorine resin, styrene resin, alkyd resin, urethane resin, amide resin and polyolefin resin) It is also possible to use. When the resin is used in combination, an antistatic layer having a proportion of the polyester resin in the binder of 51 to 100% by weight is preferable. The proportion of the binder in the entire antistatic layer may be, for example, 50 to 95% by weight, and usually 60 to 90% by weight.

<Lubricant>

The antistatic agent composition used in forming the antistatic layer in the techniques disclosed herein is a lubricant containing at least one member selected from the group consisting of a fatty acid amide, a fatty acid ester, a silicone lubricant, a fluorine lubricant and a wax lubricant Is a preferred form. Even in a form in which the surface of the antistatic layer is not subjected to further peeling treatment (for example, coating and drying of a known peeling agent such as a silicone-based releasing agent and a long-chain alkyl-based releasing agent) by using the lubricant, It is possible to obtain an antistatic layer having both of the adhesiveness of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer. The form in which the surface of the antistatic layer is not further subjected to the peeling treatment can prevent the peeling due to the peeling treatment agent (for example, whitening by preservation under the heating and humidifying conditions) desirable. It is also advantageous in terms of solvent resistance.

Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, N-oleyl palmitic acid amide, But are not limited to, stearic acid amide, stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylene bisstearic acid amide, Hexamethylenebisbenzamide amide, hexamethylene bis-stearamide, hexamethylene hydroxystearamide, N, N'-dicyclohexylmaleimide, amide, amide, amide, amide, amide, acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, N, N'-distearyl sebacic acid amide, ethylene bis-oleic acid amide, ethylene bis-erucic acid amide, hexamethylene N, N'-dioleoyl sebacic acid amide, m-xylylene bis stearic acid amide, m-xylylene bis hydroxystearic acid amide, N, N'-dioleoyl adipic acid amide, , N'-stearyl isophthalic acid amide, and the like. These lubricants may be used alone or in combination of two or more.

Specific examples of the fatty acid esters include polyoxyethylene bisphenol A lauric acid ester, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, behenic acid monoglyceride, 2-ethylhexanoate, But are not limited to, isopropyl palmitate, isopropyl palmitate, cholesteryl isostearate, lauryl methacrylate, methyl coconut fatty acid, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, , Pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, isostearyl stearate, 2-ethylhexanoic acid triglyceride, butyl laurate, octyl oleate and the like . These lubricants may be used alone or in combination of two or more.

Specific examples of the silicone base lubricant include polydimethylsiloxane, polyether-modified polydimethylsiloxane, amino-modified polydimethylsiloxane, epoxy-modified polydimethylsiloxane, carbinol-modified polydimethylsiloxane, mercapto- modified polydimethylsiloxane, Methylol modified silicone, methacryl modified polydimethylsiloxane, phenol modified polydimethylsiloxane, silanol modified polydimethylsiloxane, aralkyl modified polydimethylsiloxane, fluoroalkyl modified polydimethylsiloxane, long chain alkyl modified polydimethylsiloxane, Ester-modified polydimethylsiloxane, higher fatty acid amide-modified polydimethylsiloxane, and phenyl-modified polydimethylsiloxane. These lubricants may be used alone or in combination of two or more.

Specific examples of the fluorine-containing lubricant include perfluoroalkane, perfluorocarboxylic acid ester, fluorine-containing block copolymer, polyether polymer having fluorinated alkyl group, and the like. These lubricants may be used alone or in combination of two or more.

Specific examples of the wax-based lubricants include petroleum waxes (such as paraffin wax), vegetable waxes (such as carnauba wax), mineral waxes (such as montan wax), higher fatty acids (such as cetric acid), triglycerides And the like). These lubricants may be used alone or in combination of two or more.

The proportion of the lubricant in the whole antistatic layer may be 1 to 50% by weight, and usually 5 to 40% by weight. If the content of the lubricant is too small, the slidability tends to decrease. If the content of the lubricant is too large, the pressure-sensitive adhesive properties and the peel strength (adhesive force) on the back surface may deteriorate.

The antistatic agent composition for forming the antistatic layer preferably contains at least one member selected from the group consisting of a silane coupling agent, an epoxy crosslinking agent, a melamine crosslinking agent and an isocyanate crosslinking agent as the crosslinking agent, By using a cross-linking agent and / or an isocyanate-based cross-linking agent. (For example, polythiophenes doped with polyaniline sulfonic acid or polyanions) can be immobilized in the binder when the antistatic layer is formed, which is excellent in water resistance and solvent resistance, Effect can be realized. Particularly, use of a melamine-based crosslinking agent improves water resistance and solvent resistance. By using an isocyanate-based crosslinking agent, water resistance and adhesiveness of the ink are improved. When these crosslinking agents are used in combination, water resistance, solvent resistance,

As the melamine-based crosslinking agent, melamine, alkylated melamine, methylol melamine, alkoxylated methyl melamine, and the like can be used.

As the isocyanate crosslinking agent, it is preferable to use a blocked isocyanate crosslinking agent stable in an aqueous solution. Specific examples of the blocked isocyanate-based crosslinking agent include an isocyanate-based crosslinking agent that can be used in the production of a general pressure-sensitive adhesive layer or antistatic layer in the presence of an alcohol, a phenol, a thiophenol, an amine, an imide, a oxime, a lactam, , Mercaptans, imines, ureas, diaryl compounds and sodium bisulfite.

Antistatic agents, colorants (pigments, dyes, etc.), flowability-adjusting agents (thixotropic agents, thickeners, etc.), film-forming auxiliaries, surfactants (defoaming agents, etc.) Preservatives, and the like. It is also possible to add a glycidyl compound, a polar solvent, a polyvalent aliphatic alcohol, a lactam compound and the like as a conductivity improver.

&Lt; Formation of antistatic layer >

The antistatic layer imparts a liquid composition (a coating material for forming an antistatic layer, an antistatic agent composition) obtained by dissolving or dispersing an additive to be used according to the conductive polymer component or the like to a substrate (protective film for polarizer) dissolved or dispersed in a suitable solvent , And the like. For example, a method of applying the coating material to one surface of a substrate (protective film for polarizer), drying, and optionally curing (heat treatment, ultraviolet ray treatment, etc.) may be employed. The NV (nonvolatiles) of the coating material may be, for example, 5% by weight or less (typically 0.05 to 5% by weight) and usually 1% by weight or less (typically 0.10 to 1% by weight) . In the case of forming the antistatic layer with a small thickness, it is preferable that NV of the coating material is, for example, 0.05 to 0.50 wt% (for example, 0.10 to 0.40 wt%). By using such a low NV coating material, a more uniform antistatic layer can be formed.

As the solvent constituting the coating material for forming the antistatic layer, it is preferable that the antistatic layer can stably dissolve or disperse the components to be formed. Such a solvent may be an organic solvent, water, or a mixture thereof. Examples of the organic solvent include esters such as ethyl acetate; Ketones such as methyl ethyl ketone, acetone, and cyclohexanone; Cyclic ethers such as tetrahydrofuran (THF) and dioxane; aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane; Aromatic hydrocarbons such as toluene and xylene; Aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, and cyclohexanol; Glycol ethers such as alkylene glycol monoalkyl ethers (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) and dialkylene glycol monoalkyl ether; And the like can be used. In a preferred form, the solvent of the coating material is water or a water-based mixed solvent (for example, a mixed solvent of water and ethanol).

In addition, in order to improve dispersion stability with respect to a solvent, it is possible to include a basic organic compound capable of coordinating or bonding as an ion pair in the anion group of the polyanion. Examples of the basic organic compound include a known amine compound, a hydrochloride salt of an amine compound, a cationic emulsifier, and a basic resin.

Specific examples of the basic organic compound include aliphatic amines such as methyloctylamine, methylbenzylamine, N-methyl aniline, dimethylamine, diethylamine, diethanolamine, N-methylethanolamine, di- , Methyl-isopropanolamine, dibutylamine, di-2-ethylhexylamine, aminoethylethanolamine, 3-amino-1-propanol, isopropylamine, monoethylamine, 2-ethylhexylamine, Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) Amines such as ethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane, monomethylamine, monoethylamine, stearylamine , Hydrochloric acid salts of primary amines such as hydrochloric acid, nitric acid, sulfuric acid, nitric acid, sulfuric acid, A salt of a tertiary amine such as trimethylamine, triethylamine or stearyldimethylamine, a quaternary ammonium salt such as stearyltrimethylammonium chloride, distearyldimethylammonium chloride or stearyldimethylbenzylammonium chloride, a monoethanolamine, Hydrochloride of ethanolamine such as diethanolamine and triethanolamine, and hydrochloride of polyethylenepolyamines such as ethylenediamine and diethylenetriamine.

Specific examples of the cationic emulsifier include alkylammonium salts, alkylamidobetaines, alkyldimethylamine oxides, and the like.

Specific examples of the basic resin include a polyester-based, an acrylic-based, and a urethane-based polymer copolymer and have a weight average molecular weight (Mw) of 1,000 to 1,000,000. If the weight average molecular weight of the basic resin is less than 1000, sufficient steric hindrance can not be obtained and the dispersing effect may be deteriorated. If the weight average molecular weight is more than 1,000,000, the cohesive action may occur.

The amine value of the basic resin is preferably 5 to 200 mgKOH / g. If it is less than 5 mgKOH / g, the interaction of the polythiophenes with the polyanion species doped with the polythiophenes tends to become insufficient, and a sufficient dispersing effect may not be obtained in some cases. On the other hand, if the amine value of the basic resin exceeds 200 mgKOH / g, the steric hindrance layer becomes smaller than the affinity for the polyanion which is doped to the polythiophene, and the dispersing effect becomes insufficient in some cases.

Examples of the basic resin include Solsperse 17000, Solsperse 20000, Solsperse 24000, Solsperse 32000 (manufactured by Zeneca KK), Disperbyk-160, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk-170, Disperbyk-2000 (Manufactured by Nippon Shokubai Kabushiki Kaisha), Disperbyk-2001 (manufactured by Big Chemical), Ajisper PB711, Ajisper PB821, Ajisper PB822, Ajisper PB824 (manufactured by Ajinomoto K.K.), Epomin 006, EFKA 4300, EFKA 4510 (manufactured by EFKA) and Disalone DA-400N (manufactured by Gusumoto Kasei Kagaku Co., Ltd.), which can be used alone or in combination. Particularly, Ajisper PB821, Ajisper PB822 and Ajisper PB824 are preferable from the viewpoints of dispersibility and conductivity at the time of use.

The content of the basic compound is not limited, but is preferably 1 part by weight to 100,000 parts by weight, more preferably 10 parts by weight to 100,000 parts by weight, based on 100 parts by weight of the total of polythiophenes and polyanions Can be added.

&Lt; Characteristics of Antistatic Layer >

The thickness of the antistatic layer (after heat elongation) is preferably 100 nm or less, more preferably 3 to 100 nm, and still more preferably 20 to 80 nm. If the thickness of the antistatic layer is too small, it is difficult to uniformly form the antistatic layer (for example, the thickness of the antistatic layer varies in accordance with the location), and the appearance of the polarizing plate tends to be uneven . On the other hand, if it is too thick, the properties (optical characteristics, dimensional stability, etc.) of the polarizing plate may be affected.

The surface resistivity (Ω / □) measured on the surface of the antistatic layer is preferably 1.0 × 10 ⁸ or less, more preferably 1.0 × 10 ⁴ to 1.0 × 10 ⁸ , and still more preferably 1.0 × 10 ⁶ To 1.0 x 10 &lt; ^{7 &} gt ;. The polarizing plate exhibiting the surface resistance value within the above range is capable of suppressing the charging of the surface protective film for the polarizing plate due to the triboelectrification occurring in the processing step and the carrying step to thereby prevent attraction of the dust or deterioration in workability And can be suitably used. The surface resistance value can be calculated from a surface resistance value measured under an atmosphere of a temperature of 23 DEG C and a humidity of 50% RH using a commercially available insulation resistance measuring apparatus.

&Lt; First pressure-sensitive adhesive layer &

A first pressure-sensitive adhesive layer may be laminated on at least one side of the polarizing plate, and another optical member (for example, a retardation film or a retardation film) may be provided on a surface of the first pressure- Liquid crystal display device, etc.) (see Fig. 2). A suitable pressure-sensitive adhesive (pressure-sensitive adhesive composition) can be used for the first pressure-sensitive adhesive layer, and the kind thereof is not particularly limited. Examples of the pressure-sensitive adhesive include rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone pressure-sensitive adhesives, urethane pressure-sensitive adhesives, vinyl alkyl ether pressure-sensitive adhesives, polyvinyl alcohol pressure-sensitive adhesives, polyvinylpyrrolidone pressure-sensitive adhesives, polyacrylamide pressure-sensitive adhesives and cellulose pressure-sensitive adhesives. Among these pressure-sensitive adhesives (pressure-sensitive adhesive compositions), those having excellent optical transparency, suitably wettability, cohesiveness and adhesiveness, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as this feature.

Examples of the method for forming the first pressure sensitive adhesive layer include a method of applying the pressure sensitive adhesive (pressure sensitive adhesive composition) to a separator which has been subjected to a release treatment, drying and removing a polymerization solvent to form a pressure sensitive adhesive layer and then transferring the pressure sensitive adhesive layer onto a polarizing plate, Applying the pressure-sensitive adhesive, and drying and removing a polymerization solvent or the like to form a pressure-sensitive adhesive layer on the polarizer. Further, in application of the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added. As the separator treated for separation, a silicon separator is preferably used.

In the step of applying the pressure-sensitive adhesive (pressure-sensitive adhesive composition) on the separator and drying the pressure-sensitive adhesive layer to form the pressure-sensitive adhesive layer, the pressure-sensitive adhesive may be dried appropriately in accordance with the purpose. Preferably, a method of heating and drying the coating film is used. The heat drying temperature is preferably 40 to 200 占 폚, more preferably 50 to 180 占 폚, particularly preferably 70 to 170 占 폚. By setting the heating temperature within the above range, a pressure-sensitive adhesive layer having excellent adhesive properties can be obtained.

As a method of forming the pressure-sensitive adhesive layer, various methods are used. Specifically, it is possible to use a roll coating, a kiss roll coating, a gravure coat, a reverse coat, a roll brush, a spray coat, a dip roll coat, a bar coat, a knife coat, an air knife coat, a curtain coat, An extrusion coating method and the like.

The thickness of the first pressure-sensitive adhesive layer is preferably 2 to 50 占 퐉, more preferably 2 to 40 占 퐉, and still more preferably 5 to 35 占 퐉.

The separator can protect the first pressure-sensitive adhesive layer until it is provided for practical use. Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate and polyester film, porous materials such as paper, cloth and nonwoven fabric, nets, foam sheets, metal foils, A plastic film can be suitably used because of its excellent surface smoothness. The plastic film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, and examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, A copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

If necessary, the separator may also be subjected to antistatic treatment such as releasing treatment with a releasing agent such as silicone, fluorine, long chain alkyl or fatty acid amide-based releasing agent or silica powder, antistatic treatment, coating type, kneading type or vapor deposition type. Particularly, the releasability from the first pressure-sensitive adhesive layer can be further improved by suitably carrying out the surface treatment of the release film, such as silicone treatment, long chain alkyl treatment or fluorine treatment.

The thickness of the separator is preferably 5 to 50 mu m, more preferably 15 to 40 mu m.

The polarizing plate disclosed herein may be embodied as including an antistatic layer, a protective film for a polarizer, a polarizer, and an intervening layer (such as an adhesive layer or a first pressure-sensitive adhesive layer) and further including another layer.

<Polarizing plate having a surface protective film for a polarizing plate>

The polarizing plate having the surface protective film of the present invention is characterized in that the polarizing plate and the surface protective film for polarizing plate are laminated on the antistatic layer of the polarizing plate via the pressure sensitive adhesive layer of the polarizing plate surface protective film . The polarizing plate having a surface protective film of the present invention has a specific configuration (in order of lamination), and when the polarizing plate is laminated (adhered) to a liquid crystal display (LCD) Since the antistatic layer constituting the protective film for the side wall and the antistatic layer constituting the polarizing plate are in specific positions (in the order of lamination), it is possible to prevent the destruction of the whitening of the panel or the tag of the liquid crystal display device or the like, It is excellent and useful. Further, the pressure-sensitive adhesive layer does not use an antistatic component, so that it has excellent stain resistance and has an antistatic layer constituting the polarizing plate, thereby being excellent in flexibility and durability (scratch resistance) and is useful.

[Example]

Hereinafter, some embodiments related to the present invention will be described, but the present invention is not intended to be limited to these specific examples. In the following description, &quot; part &quot; and &quot;% &quot; are by weight unless otherwise specified. The amount (amount added) in the table is shown.

Each characteristic in the following description was measured or evaluated as follows. The methods for preparing the polarizing plate and the surface protective film for a polarizing plate and the polarizing plate having the surface protective film for a polarizing plate described below were prepared according to the constitution, positional relationship, and the like described in Table 1.

<Preparation of Protective Film for Polarizer>

Acrylic resin (trade name: Acryphet VH, Tg: 113 ° C, manufactured by Mitsubishi Rayon Co., Ltd.) was vacuum-dried at 100 ° C to degas moisture and remaining oxygen. 30 parts by weight of an acrylic rubber (trade name: AR12, manufactured by Nippon Zeon Co., Ltd.) was added to 100 parts by weight of the degassed acrylic resin, and the mixture was charged into a twin screw extruder (equipment name: TEM35B, Ltd.), melted at a cylinder set temperature of 230 to 270 캜, and pelletized to obtain raw material pellets. The raw pellets thus obtained were vacuum-dried at 100 占 폚 and fed to a single screw extruder (equipment name: SE-65, manufactured by Toshiba Kiki K.K.) in which the feed hopper and the extruder were purged with nitrogen, melted at 230 to 270 占 폚 in a cylinder set Passed through a T-die of a coat hanger type, cooled on a casting roll made of chrome plated at 120 DEG C and a casting roll made of chrome plated with nickel at 90 DEG C, and then laminated on an acrylic resin film (thickness: ).

&Lt; Preparation of Protective Film for Polarizer Having Antistatic Layer (Polymer Type) >

Denatron P-502RG (containing PEDOT / PSS) manufactured by Nagase Chemtex Co., Ltd., which is an antistatic agent composition, was coated on the acrylic resin film (thickness: 40 탆) as a protective film for the polarizer using wire bar # 6, For 60 seconds to prepare a protective film for a polarizer having an antistatic layer (thickness of the antistatic layer: 80 nm). The surface resistance value of the obtained antistatic layer surface was 3.12 x 10 ⁶ ? / ?.

&Lt; Preparation of protective film for polarizer having antistatic layer (metal type) >

A tin oxide S-1 manufactured by Mitsubishi Materials Denshi Kasei Co., Ltd., which is an antistatic agent composition, was coated on an acrylic resin film (thickness: 40 탆) as a protective film for a polarizer using Wire Bar # 6, And dried for 60 seconds to prepare a protective film for a polarizer having an antistatic layer (thickness of the antistatic layer: 80 nm). The surface resistance value of the obtained antistatic layer surface was 1.21 x 10 &lt; ⁶ &gt;

<Production of Polarizer>

While immersing the polyvinyl alcohol film (polymerization degree: 2300, saponification degree: 99.9%, width: 1000 mm, thickness: 75 占 퐉, VR-PS7500, manufactured by Kuraray Co., Ltd.) in pure water at 30 占 폚 for 75 seconds And stretched to 2.5 times the draw ratio.

Then, the solution was stained for 45 seconds in an aqueous iodine solution (weight ratio: pure water / iodine (I) / potassium iodide (KI) = 100 / 0.01 / 1) at 30 占 폚.

Thereafter, it was stretched so as to have a draw ratio of 5.8 in a 4 wt% boric acid aqueous solution. After stretching, the film was immersed in pure water for 10 seconds, and dried at 50 DEG C for 3 minutes while maintaining the tension of the film to obtain a polarizer. The thickness of this polarizer was 25 mu m and the water content was 14 wt%.

<Preparation of aqueous adhesive solution>

100 parts by weight of a polyvinyl alcohol resin (average degree of polymerization: 1200, saponification degree: 98.5 mol%, acetoacetyl group degree of deformation: 5 mol%) containing acetoacetyl group and 50 parts by weight of methylolmelamine were mixed with pure water (water temperature: 30 DEG C) And adjusted to a solid content concentration of 3.7% by weight to prepare an aqueous solution. 18 parts by weight of an alumina colloid aqueous solution (average particle diameter: 15 nm, solid concentration: 10% by weight, positive charge) was added to 100 parts by weight of the aqueous solution to prepare an aqueous adhesive solution. The viscosity of the adhesive aqueous solution was 9.6 mPa · s. The pH of the aqueous adhesive solution was in the range of 4 to 4.5. This was used as an adhesive aqueous solution.

<Antistatic layer of polarizing plate was laminated on the pressure-sensitive adhesive layer side of the surface protective film for polarizing plate (on the surface protective film side for polarizing plate)>

The adhesive aqueous solution was coated on the surface opposite to the antistatic layer of the polarizer protective film having the antistatic layer so that the thickness of the dried adhesive layer became about 55 nm to prepare a protective film for a polarizer having an adhesive layer.

Thereafter, a protective film for a polarizer having the above-mentioned adhesive layer was laminated on one surface of the polarizer at a temperature of 23 占 폚 to form an adhesive layer of a polarizing protective film having the adhesive layer, Thereby obtaining a laminate. The laminate was dried at 70 캜 for 10 minutes to prepare a polarizing plate (1).

&Lt; Polarizer of polarizing plate was laminated on the pressure-sensitive adhesive layer side of the surface protective film for polarizing plate (polarizer side) >

On the surface of the antistatic layer of the protective film for a polarizer having the antistatic layer, the above-mentioned adhesive aqueous solution was applied so that the thickness of the dried adhesive layer became about 55 nm to prepare a protective film having an adhesive layer.

Thereafter, a protective film for a polarizer having the above-mentioned adhesive layer was laminated on one surface of the polarizer at a temperature of 23 占 폚 to form an adhesive layer of a polarizing protective film having the adhesive layer, Thereby obtaining a laminate. The laminate was dried at 70 캜 for 10 minutes to prepare a polarizing plate (2).

&Lt; Preparation of a polarizing plate in which a polarizing protective film of a polarizing plate having no antistatic layer was laminated on the pressure-sensitive adhesive layer side of the surface protective film for polarizing plate &

The polarizer protective film having the antistatic layer of the polarizing plate 1 was coated with the aqueous adhesive solution so that the thickness of the dried adhesive layer was about 55 nm on one side of the protective film for polarizer having no antistatic layer, Was prepared. &Lt; tb &gt; &lt; TABLE &gt;

Thereafter, a protective film for a polarizer having the above-mentioned adhesive layer was laminated on one surface of the polarizer at a temperature of 23 占 폚 to form an adhesive layer of a polarizing protective film having the adhesive layer, Thereby obtaining a laminate. The laminate was dried at 70 캜 for 10 minutes to prepare a polarizing plate (3).

<Surface Protective Film for Polarizing Plate Used>

<E-MASK RP207>

As the surface protective film for a polarizing plate, "E-MASK RP207" manufactured by Nitto Denko Corporation having the composition shown in Table 1 was used.

<AS3-830>

As the surface protective film for a polarizing plate, "AS3-830" manufactured by Fujimori Kogyo Kabushiki Kaisha having the composition shown in Table 1 was used.

<NSA35-H>

As a surface protective film for a polarizing plate, "trade name NSA35-H" manufactured by Aigaken Kabushiki Kaisha under the composition shown in Table 1 was used.

&Lt; Preparation of polarizing plate having surface protective film for polarizing plate >

The surface of the polarizing plate 1 on which the antistatic layer is exposed or the surface on which the polarizer of the polarizing plate 2 is exposed or the polarizing protective film of the polarizing plate 3 without the antistatic layer are exposed On the surface, the surface of the pressure-sensitive adhesive layer of the surface protective film for polarizing plate was joined with a roller and left for 5 minutes at room temperature to prepare a polarizing plate having a surface protective film for polarizing plate.

&Lt; Measurement of Surface Resistance Value of Antistatic Layer Surface of Polarizer >

The measurement was carried out in accordance with JIS-K-6911 using a resistivity meter (Hiresta UP MCP-HT450 type, manufactured by Mitsubishi Kagaku Analytec) in an atmosphere of a temperature of 23 캜 and a humidity of 50% RH. The applied voltage was 100 V and the surface resistance value was read 10 seconds after the start of the measurement.

The surface resistance (Ω / □) measured on the surface of the antistatic layer of the polarizing plate was measured in the state that the antistatic agent composition (solution) was coated on the base film and dried, and then the antistatic layer was formed.

The surface resistance (Ω / □) measured on the surface of the antistatic layer in the present invention is preferably 1.0 × 10 ⁸ or less, more preferably 1.0 × 10 ⁴ to 1.0 × 10 ⁸ , Is 1.0 × 10 ⁶ to 1.0 × 10 ⁷ . The surface protective film for a polarizing plate having an antistatic layer exhibiting a surface resistance value within the above range is suitably used as a surface protective film used in processing or transporting an article to avoid static electricity such as a liquid crystal cell or a semiconductor device .

<Measurement of peeling electrification voltage (peeling electrification preventing property)>

As shown in Fig. 3, the surface protective film 2 for the polarizing plate according to each example was cut into a size of 70 mm in width and 130 mm in length, the release liner was peeled from the surface of the pressure-sensitive adhesive layer, A polarizing plate 3 (width: 70 mm, length: 30 mm) according to each example bonded to a plate 31 (trade name "acrylite", thickness: 1 mm, width: 70 mm, length: 100 mm, manufactured by Mitsubishi Rayon Co., 100 mm) so that one end of the surface protective film 2 for the polarizing plate was projected out of the end of the polarizing plate 20 by 30 mm, and pressed with a hand roller through a pressure-sensitive adhesive layer to form a sample.

The sample was allowed to stand for one day under an environment of 23 DEG C x 50% RH, and then set at a predetermined position on a sample holding table 30 having a height of 20 mm. The end of the surface protective film 1 protruding 30 mm from the polarizing plate 3 was fixed to an automatic winding machine (not shown), and peeled off at a peeling angle of 150 ° and a peeling rate of 30 m / min. The electric potential of the surface of the adherend (polarizing plate) generated at this time was peeled off from a potential meter 32 (type "KSD-0103" manufactured by Kasuga Denshiki Co., Ltd.) fixed at a position 100 mm high from the center of the polarizer 20 Voltage was measured. The measurement was carried out in an environment of 23 캜 and 50% RH. When the polarizing plate had no antistatic layer, the surface potential of the protective film for the polarizer was measured with the peeling electrification voltage instead of the antistatic layer surface.

The peeling electrification voltage is a peeling electrification voltage mainly derived from the antistatic layer constituting the surface protective film for a polarizing plate of the present invention, and contributes to prevention of peeling electrification.

The peeling electrification voltage (maximum value) of the surface protective film for a polarizing plate of the present invention is preferably 0.4 kV or less, and more preferably 0.3 kV or less. If the peeling electrification voltage exceeds 0.4 kV, the polarizer arrangement in the polarizing plate is disturbed. In addition, as the evaluation in Table 1, evaluation was made as 0 (good) for 0.4 kV or less and x (heat) for a case exceeding 0.4 kV.

<Contamination resistance>

After the surface of the antistatic layer of the antistatic layer of the polarizing plate was adhered to the surface of the pressure-sensitive adhesive layer of the surface protective film for polarizing plate, the surface protective film for polarizing plate was peeled off at a peeling rate of 30 m / min from the polarizing plate after holding at 70 캜 for 120 hours. Was confirmed by eyes. Further, in the case where the surface of the polarizing plate to which the surface of the pressure-sensitive adhesive layer of the polarizing plate surface protective film is adhered is a protective film for a polarizer, not an antistatic layer, the presence or absence of contamination on the surface of the polarizing protective film was visually confirmed.

As the evaluation, the case where the contamination was not confirmed was evaluated as? (Good), and the case where the contamination was confirmed was evaluated as? (Thermal).

<Steel Wool Test (Durability)>

(Durability) of the surface of the antistatic layer was evaluated under the condition that a steel wool (# 0000, manufactured by Nippon Steel Wool Co., Ltd.) was attached to a circular jig having a radius of 25 mm, Respectively. (Good) when the number of scratches was 10 or less, and X (hot) when the number of scratches was 10 or more. Further, when the surface of the polarizing plate to which the surface of the pressure-sensitive adhesive layer of the surface protective film for polarizing plate is adhered is not an antistatic layer, evaluation of durability is not performed.

Table 1 shows the blending contents, various measurements and evaluations of the polarizing plate having the surface protective film for a polarizing plate according to Examples and Comparative Examples.

&Quot; Polymer type &quot; in Table 1 means that a conductive polymer (PEDOT / PSS) is used as an antistatic component, and the metal type is tin oxide as an antistatic component.

The term &quot; side of the surface protective film for polarizing plate &quot; in Table 1 refers to the case where the surface of the pressure sensitive adhesive layer of the surface protective film for polarizing plate is in contact with the exposed surface of the antistatic layer on the side opposite to the polarizer.

Refers to the case where the surface of the pressure-sensitive adhesive layer of the surface protective film for polarizing plate is in contact with the exposed surface of the polarizer on the opposite side of the protective film for polarizer.

When the antistatic layer of the polarizing plate is not present, the durability is not evaluated.

From Table 1, it was confirmed that the polarizing plate and the surface protective film for a polarizing plate in Example 1 had an antistatic layer at a specific position, so that the antistatic property of peeling, stain resistance and durability (scratch resistance) were excellent.

On the other hand, from Table 1, it can be seen from Table 1 that in the comparative example, in the absence of the antistatic layer constituting the polarizing plate or the antistatic layer constituting the polarizing plate or the surface protective film for polarizing plate, The durability is inferior and the durability of the antistatic layer using the antistatic component of metal type is also inferior. When the antistatic component is contained in the pressure-sensitive adhesive layer constituting the surface protective film for the polarizing plate It was confirmed that the stain resistance was poor.

The surface protective film constituting the polarizing plate having the surface protective film disclosed herein is suitably used for a polarizing plate used as a component of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescent (EL) .

1: Polarizing plate having a surface protective film for polarizing plate
2: Surface protective film for polarizer
3: polarizer
10: Antistatic layer
11: base film
12: pressure-sensitive adhesive layer
20: antistatic layer
21: Protective film for polarizer
22: Polarizer
23: first pressure-sensitive adhesive layer
24: retardation film
30: Sample Stands
31: acrylic plate
32: Potentiometer

Claims (3)

An antistatic layer formed by an antistatic agent composition comprising a polarizer and a protective film for a polarizer on at least one side of the polarizer and a conductive polymer on a side opposite to a side of the polarizer protective film which is in contact with the polarizer, ,
A polarizing plate having a base film and a surface protective film for a polarizing plate having a pressure-sensitive adhesive layer on one side of the base film and a surface protective film for polarizing plate having an antistatic layer on the side opposite to the side in contact with the pressure-
The surface protective film for the polarizing plate is laminated on the antistatic layer of the polarizing plate via the pressure-sensitive adhesive layer of the surface protective film for the polarizing plate,
Wherein the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains no antistatic component. The polarizer protective film according to claim 1, wherein the polarizer protective film is formed of at least one resin selected from the group consisting of a (meth) acrylic resin, a cyclic olefin resin, a polyester resin and a polycarbonate resin Wherein the polarizing plate has a surface protective film for a polarizing plate. The polarizing plate according to any one of claims 1 to 3, wherein the protective film for polarizer has an ultraviolet ray absorbing function.

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