KR102637902B1 - Polarizing plate - Google Patents

Abstract

[Problem] The present invention uses a polarizing plate (polarizing plate) having a surface protection film for a polarizing plate having a specific configuration (stacking order), and then laminating (attaching) this polarizing plate to a liquid crystal display (LCD) or the like, and then using the polarizing plate. Provides an optical member having a surface protection film for polarizing plates that can prevent whitening of panels such as liquid crystal display devices and destruction of tags when peeling off a surface protection film, and has excellent peeling antistatic properties, contamination resistance, and durability. do.
[Solution] A polarizing plate having a surface protection film of the present invention has a polarizer and a protective film for polarizers on at least one side of the polarizer, and includes a conductive polymer on the side of the protective film for polarizers opposite to the surface in contact with the polarizer. For a polarizing plate having an antistatic layer formed by an antistatic agent composition, a base film, and an adhesive layer on one side of the base film, and an antistatic layer on the side opposite to the side in contact with the adhesive layer of the base film. It is a polarizing plate having a surface protection film for a polarizing plate having a surface protection film, and is characterized in that the surface protection film for a polarizing plate is laminated on an antistatic layer of the polarizing plate through an adhesive layer of the surface protection film for a polarizing plate.

Description

Polarizer{POLARIZING PLATE}

The present invention relates to a polarizing plate having a surface protection film for a polarizing plate. In particular, the polarizing plate having the surface protection film can be used alone or as an optical film laminated thereon to form an image display device such as a liquid crystal display (LCD), an organic EL display, a CRT, or a PDP.

In liquid crystal displays, organic EL displays, etc., from their image forming method, for example, it is essential to arrange a polarizer in a liquid crystal cell, and a polarizer is generally attached.

For example, in the production of a liquid crystal display panel, the polarizing plate bonded to the liquid crystal cell is an adhesive layer that constitutes the surface protection film for the polarizing plate in order to prevent scratches and contamination during processing, transportation, etc. It is attached to the surface of the polarizer through an interposer. However, this surface protection film is peeled off at a stage when it is no longer needed, but when peeling off, static electricity is generated and defects such as whitening of the liquid crystal panel or destruction of the tag become problems.

In order to suppress the generation of such static electricity, attempts have been made to impart antistatic properties by blending an antistatic agent such as an alkali metal salt in the adhesive layer (for example, patent document 1).

Japanese Patent Publication No. 2009-251281

However, by mixing an antistatic agent in the adhesive layer as shown in Patent Document 1, problems such as the adhesive strength based on the adhesive layer becoming insufficient or the antistatic agent bleeding out and contaminating the surface of the polarizing plate occur, resulting in poor adhesive properties and contamination resistance. Coexistence is becoming difficult.

Additionally, in the polarizing plate after peeling off the surface protection film for polarizing plate, problems such as scratches may occur in subsequent processes, and durability such as scratch resistance is required.

Therefore, as a result of intensive research in consideration of the above circumstances, the present invention has been developed by using a polarizing plate (polarizing plate) having a surface protection film for a polarizing plate having a specific configuration (stacking order), thereby laminating (attaching) this polarizing plate to a liquid crystal display device, etc. When peeling off the surface protection film for polarizer after use, it can prevent whitening of panels such as liquid crystal display devices and destruction of tags, and has excellent peeling antistatic properties, as well as excellent contamination resistance and durability. The purpose is to provide an optical member having a.

That is, the polarizing plate having the surface protection film of the present invention has a polarizer and a protective film for a polarizer on at least one side of the polarizer, and a charged plate containing a conductive polymer on the side of the protective film for the polarizer opposite to the side in contact with the polarizer. A polarizing plate having an antistatic layer formed of an antistatic agent composition, and a surface protection film for polarizing plates having a base material and an adhesive layer on one side of the base film, and having an antistatic layer on the side opposite to the side in contact with the adhesive layer of the base film. A polarizing plate having a surface protection film for a polarizing plate, wherein the surface protection film for a polarizing plate is laminated on an antistatic layer of the polarizing plate via an adhesive layer of the surface protective film for a polarizing plate, and the adhesive composition forming the adhesive layer is antistatic. It is characterized by not containing any ingredients.

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

As for the polarizing plate with the surface protection film of this invention, it is preferable that the said protective film for polarizers has an ultraviolet-ray absorption function.

The polarizing plate having the surface protection film for polarizing plates of the present invention includes an antistatic layer, a base film, and a surface protection film for polarizing plates having an adhesive layer formed by an adhesive composition not containing an antistatic component, and a conductive polymer. It includes a polarizing plate having an antistatic layer formed by an antistatic agent composition, a protective film for a polarizer, and a polarizer, and is laminated on the antistatic layer of the polarizing plate through an adhesive layer of the surface protection film for a polarizing plate, thereby forming a specific configuration (order of stacking). It becomes a polarizing plate (polarizing plate) having a surface protection film for a polarizing plate, and when this polarizing plate is laminated (attached) to a liquid crystal display (LCD), etc., and the surface protection film for a polarizing plate is peeled off after use, a surface protection film for a polarizing plate is formed. By locating the antistatic layer and the antistatic layer constituting the polarizing plate at a specific position (order of stacking), whitening of a panel such as a liquid crystal display device or destruction of a tag can be prevented, and the peeling antistatic property is excellent, making it useful. In addition, by containing (substantially) no antistatic component in the adhesive layer, contamination due to the antistatic component in the adhesive layer can be prevented and contamination resistance is excellent, and the antistatic layer of the polarizing plate contains a conductive polymer. It is useful because it is possible to provide an optical member having a surface protection film for a polarizing plate that is excellent in flexibility and durability (scratch resistance) by forming the antistatic agent composition.

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

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

<Overall structure of polarizing plate with surface protection film for polarizing plate>

The polarizing plate having a surface protection film for a polarizing plate disclosed herein, for example, as shown in FIG. 1, the surface protection film for a polarizing plate 2 has an adhesive layer 12 on at least one side of the base film 11, and another It has a configuration in which an antistatic layer 10 is laminated on one side, and the polarizer 3 has a protective film 21 for a polarizer on at least one side of the polarizer 22 and is in contact with the polarizer of the protective film 21 for the polarizer. Examples include those having an antistatic layer 20 laminated on one side and the other side. In addition, the polarizing plate surface protection film includes the polarizing plate 1 having a surface protection film for a polarizing plate configured to be directly laminated (in contact) with the antistatic layer 20 of the polarizing plate 3 via the adhesive layer 20. . Additionally, the polarizing plate having the surface protection film for polarizing plates disclosed herein may be of a roll type or a sheet type.

<Base film of surface protection film for polarizing plate>

The surface protection film for polarizing plates used in the present invention is characterized by having a base film, an adhesive layer on one side of the base film, and an antistatic layer on the side opposite to the surface of the base film in contact with the adhesive layer. In the technology disclosed herein, the resin material constituting the base film can be used without particular restrictions, but for example, those having excellent properties such as transparency, mechanical strength, thermal stability, moisture shielding, isotropy, flexibility, and dimensional stability can be used. It is desirable to use In particular, since the base film has flexibility, the adhesive composition can be applied using a roll coater or the like and can be wound into a roll, which is useful.

As the base film (base material, support), for example, polyester-based polymer, cellulose-based polymer, polycarbonate-based polymer, acrylic polymer, etc. are used as the main resin component (main component in the resin component, typically 50% by weight or more). A plastic film composed of a resin material (component that occupies) can be preferably used as the base film. The base film may be a blend of two or more of these polymers.

The resin material constituting the base film may be blended with various additives such as antioxidants, ultraviolet absorbers, plasticizers, and colorants (pigments, dyes, etc.) as needed. For example, known or customary surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, or application of a primer may be performed. This surface treatment may be, for example, a treatment to increase the adhesion between the base film and the adhesive layer (anchoring property of the adhesive layer).

The surface protection film for polarizing plates used in the present invention can also use a plastic film that has been subjected to antistatic treatment as the base film. By using the base film, it is preferable because charging of the surface protection film for polarizing plates itself when peeled is suppressed. In addition, the base film is a plastic film, and by antistatic treatment on the plastic film, charging of the surface protection film itself for a polarizing plate is reduced, and an excellent antistatic ability to the adherend is obtained. Also, as a method for imparting an antistatic function, there is no particular limitation and conventionally known methods can be used, for example, applying an antistatic resin consisting of an antistatic agent and a resin component, a conductive polymer, or a conductive resin containing a conductive material. Examples include a method of depositing or plating a conductive material, or a method of kneading an antistatic agent, etc.

The thickness of the base film is 50 μm or more, preferably 50 to 200 μm, more preferably 70 to 150 μm, and even more preferably 75 to 130 μm. If the thickness of the base film is within the above range, the bonding workability when bonding the surface protection film for a polarizing plate to a polarizing plate and the transportability after bonding are improved, which is preferable.

<Adhesive layer of surface protection film for polarizer>

The adhesive layer constituting the surface protection film for a polarizing plate used in the present invention is formed of an adhesive composition, and the adhesive composition is characterized in that it does not contain an antistatic component. The adhesive composition contains an adhesive polymer, and the adhesive polymer can be used without particular limitation as long as it has adhesive properties. As the adhesive composition, for example, an acrylic adhesive containing a (meth)acrylic polymer, a urethane adhesive containing a urethane polymer, a silicone adhesive containing a silicone polymer, etc. are used, especially from the viewpoint of adhesiveness, transparency, etc. ) It is particularly preferable to use an acrylic adhesive containing an acrylic polymer.

As for the pressure-sensitive adhesive layer used in the present invention, it is preferable that the pressure-sensitive adhesive composition contains a crosslinking agent. Additionally, in the present invention, the pressure-sensitive adhesive composition can be used to form an adhesive layer. For example, when the adhesive composition is an acrylic adhesive containing the (meth)acrylic polymer, by appropriately controlling the structural units, composition ratio, selection and addition ratio of the crosslinking agent, etc. of the (meth)acrylic polymer, more heat resistance can be achieved. This excellent adhesive layer (surface protection film for polarizing plate) can be obtained.

As the crosslinking agent, isocyanate compounds, epoxy compounds, melamine-based resins, aziridine derivatives, metal chelate compounds, etc. may be used, and the use of isocyanate compounds is particularly preferred. Additionally, these compounds may be used individually or two or more types may be mixed.

Additionally, the adhesive composition may contain other known additives, for example, crosslinking catalysts, lubricants, colorants, powders such as pigments, plasticizers, tackifiers, low molecular weight polymers, surface lubricants, leveling agents, and antioxidants. , corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, thin substances, etc. can be added as appropriate depending on the intended use.

In addition, the adhesive composition is characterized in that it does not contain an antistatic component. “Does not contain an antistatic component” means that it does not substantially contain an antistatic agent, and includes an adhesive layer (e.g., an adhesive layer that does not exert an antistatic function) For example, this means that the surface resistance value of the surface of the adhesive layer is 10 ¹³ or more. In addition, when the adhesive composition contains an antistatic component, contamination usually occurs due to the antistatic component being transferred from the adhesive layer. However, in the adhesive layer used in the present invention, the adhesive composition substantially contains the antistatic component. By not containing it, this contamination can be prevented, and it has excellent contamination resistance, making it a desirable form.

<Antistatic layer of surface protection film for polarizer>

The surface protection film for a polarizing plate used in the present invention is characterized by having a base film, an adhesive layer on one side of the base film, and an antistatic layer on the side opposite to the surface of the base film in contact with the adhesive layer. By providing an antistatic layer on the outermost layer (back of the base film) of the surface protection film for a polarizing plate, a grounding effect is achieved, and antistatic peeling properties are excellent, resulting in a desirable form.

In order to form the antistatic layer, it is preferable that the base film is subjected to antistatic treatment. As the antistatic treatment, it is possible to use a general antistatic treatment method and is not particularly limited, but for example, a method of providing an antistatic layer on the back of the base film (the side opposite to the adhesive layer) can be used.

As a method of providing the antistatic layer, a method of applying an antistatic agent or an antistatic resin containing an antistatic agent and a resin component, a conductive resin composition or a conductive polymer containing a conductive material and a resin component to a base film, or a method of applying a conductive material A method of depositing or plating may be mentioned.

Examples of the antistatic agent include cationic antistatic agents having cationic functional groups (e.g., first amino group, second amino group, third amino group, etc.) such as quaternary ammonium salts and pyridinium salts; Anionic antistatic agents having anionic functional groups such as sulfonates, sulfuric acid esters, phosphonates, and phosphoric acid esters; Zwitterionic antistatic agents such as alkylbetaine and its derivatives, imidazoline and its derivatives, and alanine and its derivatives; Nonionic antistatic agents such as amino alcohol and its derivatives, glycerin and its derivatives, polyethylene glycol and its derivatives; Furthermore, an ionic conductive polymer obtained by polymerizing or copolymerizing a monomer having an ionic conductive group represented by the cationic antistatic agent, anionic antistatic agent, or amphoteric antistatic agent is included.

Specifically, the cationic antistatic agent includes a quaternary ammonium group such as alkyltrimethylammonium salt, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salt, choline acyl chloride, and polydimethylaminoethyl methacrylate. (meth)acrylate copolymers, styrene-based copolymers having quaternary ammonium groups such as polyvinylbenzyltrimethylammonium chloride, and diallylamine copolymers having quaternary ammonium groups such as polydiallyldimethylammonium chloride. Examples of the anionic antistatic agent include alkyl sulfonate salts, alkyl benzene sulfonate salts, alkyl sulfuric acid ester salts, alkyl ethoxy sulfuric acid ester salts, alkyl phosphoric acid ester salts, and styrene-based copolymers containing sulfonic acid groups. Examples of the zwitterionic antistatic agent include alkyl betaine, alkylimidazolium betaine, and carbobetaine graft copolymer. Examples of the nonionic antistatic agents include fatty acid alkylolamide, di-(2-hydroxyethyl)alkylamine, polyoxyethylene alkylamine, fatty acid glycerin ester, polyoxyethylene glycol fatty acid ester, sorbitan fatty acid ester, and polyoxysor. Non-carbonated fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyethylene glycol, polyoxyethylene diamine, copolymer made of polyether, polyester, and polyamide, methoxypolyethylene glycol (meth)acrylate, etc. You can.

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

Examples of the conductive materials 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, general-purpose resins such as polyester, acrylic, polyvinyl, urethane, melamine, and epoxy are used. In addition, when the antistatic agent is a polymer-type antistatic agent, the antistatic resin does not need to contain the above resin component. In addition, the antistatic resin can also contain methylolated or alkylolated melamine-based, urea-based, glyoxal-based, acrylamide-based compounds, epoxy-based compounds, and isocyanate-based compounds as crosslinking agents.

As a method of forming the antistatic layer by application, the antistatic resin, conductive polymer, or conductive resin composition is diluted with a solvent or dispersion medium such as an organic solvent or water, and the coating solution is applied to a base film and dried. I can hear it. 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 individually or in combination. As for the application method, known application methods are used, and specific examples include roll coat, gravure coat, reverse coat, roll brush, spray coat, air knife coat, impregnation, and curtain coat method.

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

Methods 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 deposition or plating is preferably 20 to 10,000 Å (0.002 to 1 μm), and more preferably 50 to 5,000 Å (0.005 to 0.5 μm).

<Surface protection film for polarizer>

The surface protection film for a polarizing plate used in the present invention has a base film, an adhesive layer on one side of the base film, and an antistatic layer on the side opposite to the side in contact with the adhesive layer of the base film. As a method of forming a pressure-sensitive adhesive layer by crosslinking the pressure-sensitive adhesive composition, it is generally performed after application of the pressure-sensitive adhesive composition, but it is also possible to transfer the pressure-sensitive adhesive layer made of the crosslinked pressure-sensitive adhesive composition to a base film or the like.

In addition, the method of forming the adhesive layer on the base film is not particularly limited, but for example, the adhesive composition (solution) is applied to the base film, the polymerization solvent, etc. is dried and removed to form the adhesive layer on the base film. . After that, curing may be performed for the purpose of adjusting the migration of components in the adhesive layer or adjusting the crosslinking reaction. Additionally, when applying the pressure-sensitive adhesive composition onto a base film to produce a surface protection film for a polarizing plate, one or more solvents other than the polymerization solvent may be newly added to the pressure-sensitive adhesive composition so as to enable uniform application on the base film.

Additionally, as a method for forming an adhesive layer when manufacturing the surface protection film for a polarizing plate used in the present invention, a known method used for manufacturing adhesive tapes is used. Specifically, examples include roll coat, gravure coat, reverse coat, roll brush, spray coat, air knife coating method, extrusion coating method using a die coater, etc.

The surface protection film for a polarizing plate used in the present invention is usually produced so that the thickness of the adhesive layer is about 3 to 100 μm, preferably about 5 to 50 μm. It is preferable that the thickness of the adhesive layer is within the above range because it is easy to obtain an appropriate balance of re-peelability and adhesiveness.

Additionally, the surface protection film for polarizing plates used in the present invention preferably has a total thickness of 5 to 300 μm, more preferably 10 to 200 μm, and most preferably 12 to 100 μm. If it is within the above range, the adhesion properties (repeelability, adhesiveness, etc.), workability, and appearance properties are excellent, resulting in a desirable form. Additionally, the total thickness refers to the sum of the thicknesses including all layers such as the base film, adhesive layer, antistatic layer, and other layers.

The surface protection film for a polarizing plate disclosed herein may be implemented in a form that further includes other layers in addition to the base film, adhesive layer, and antistatic layer. Examples of the other layers include an antistatic layer and an undercoating layer (anchor layer) that improves the anchoring properties of the adhesive layer.

<Polarizer>

The polarizing plate used in the present invention has a polarizer and a protective film for a polarizer on at least one side of the polarizer, and is formed of an antistatic agent composition containing a conductive polymer on the side of the protective film for the polarizer opposite to the side in contact with the polarizer. It is characterized by having an antistatic layer. Additionally, a structure in which an adhesive layer is laminated on at least one side of the polarizer can be used, and another optical member (for example, a retardation film, a liquid crystal display, etc.) can be placed on the side of the adhesive layer opposite to the surface in contact with the polarizer. etc. can be stacked. In addition, the antistatic layer located on the surface layer of the polarizing plate and the adhesive layer constituting the surface protection film for the polarizing plate are directly laminated (in contact with each other).

<Polarizer>

The polarizer used in the present invention uses a polyvinyl alcohol-based resin. As a polarizer, for example, a dichroic substance such as iodine or a dichroic dye is adsorbed on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene-vinyl acetate copolymer-based partially saponified film, and uniaxial Examples include polyene-based oriented films such as stretched ones, dehydrated products of polyvinyl alcohol, and dehydrochlorinated products of polyvinyl chloride. Among these, polarizers made of dichroic substances such as polyvinyl alcohol-based films and iodine are suitable.

A polarizer obtained by dyeing the polyvinyl alcohol-based film with iodine and stretching it uniaxially can be produced, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine, dyeing it, and stretching it to 3 to 7 times the original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, etc., and may also be immersed in an aqueous solution such as potassium iodide. Additionally, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol-based film with water, not only can contamination and anti-blocking agents on the surface of the polyvinyl alcohol-based film be removed, but also swelling of the polyvinyl alcohol-based film has the effect of preventing unevenness such as staining in dyeing. Stretching may be performed after dyeing with iodine, may be carried out while dyeing, or may be carried out after stretching and then dyed with iodine. It can be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

The thickness of the polarizer can be appropriately determined, but is preferably 30 μm or less, more preferably 28 μm or less, and even more preferably 5 to 25 μm. Such a polarizer has little thickness unevenness, is excellent in thinness and visibility, and has little dimensional change, so it is excellent in durability against thermal shock.

The polarizer has optical properties expressed by the single transmittance T and polarization degree P according to the following formula: P>-(100.929T-42.4-1) ) is preferably configured to satisfy the conditions. A polarizer configured to satisfy the above conditions uniquely has the performance required as a display for a liquid crystal TV using a large display element. Specifically, the contrast ratio is 1000:1 or more and the maximum luminance is 500㏅/㎡ or more. As another use, for example, it is bonded to the viewing side of an organic EL cell.

<Protective film for polarizer>

The material constituting the protective film for the polarizer is not particularly limited, but a polymer (resin) having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, ultraviolet ray absorption, etc. is preferred. For example, polyester polymers (polyester resin) such as polyethylene terephthalate and polyethylene naphthalate, (meth)acrylic polymers such as polymethyl methacrylate {(meth)acrylic resin}, and polycarbonate polymers ( polycarbonate-based resin) and the like. Additionally, polyethylene, polypropylene, and polyolefin (cyclic olefin resin) having a cyclo or norbornene structure can also be cited as examples of the polymer forming the protective film for the polarizer. Among these, the protective film for the polarizer is preferably formed of at least one type of resin selected from the group consisting of (meth)acrylic resin, cyclic olefin resin, polyester resin, and polycarbonate resin, It is particularly preferable to use a resin having an ultraviolet ray absorption function. These protective films for polarizers are usually bonded to the polarizer with an adhesive layer.

Additionally, the protective film for polarizer may contain one or more suitable additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, discoloration inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants, etc. The content of the polymer in the protective film for polarizer is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . If the content of the polymer in the protective film for a polarizer is 50% by weight or less, there is a risk that the polymer may not be able to sufficiently exhibit its original high transparency.

The thickness of the protective film for polarizer can be appropriately determined, but generally, from the viewpoint of strength, workability such as handling, thinness, etc., it is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 10 to 60 μm is preferred.

A functional layer such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer, or an anti-glare layer may be installed on the surface of the protective film for the polarizer that does not adhere the polarizer. In addition, the functional layers such as the hard coat layer, anti-reflection layer, anti-sticking layer, diffusion layer, and anti-glare layer can not only be installed on the polarizer protective film itself, but can also be installed separately from the polarizer protective film. .

Additionally, when laminating a polarizer and a protective film for a polarizer, an easy-adhesion layer can be provided between the protective film for a polarizer and the adhesive layer.

<Anti-static layer of polarizer>

A polarizing plate having a surface protection film for a polarizing plate of the present invention has a polarizer and a protective film for a polarizer on at least one side of the polarizer, and a charge comprising a conductive polymer on the side of the protective film for the polarizer opposite to the side in contact with the polarizer. It has a polarizing plate having an antistatic layer formed of an antistatic agent composition, and the surface protection film for a polarizing plate is laminated on the antistatic layer of the polarizing plate through an adhesive layer of the surface protection film for a polarizing plate. Since the antistatic layer is formed of an antistatic agent composition containing a conductive polymer, an increase in surface resistance can be suppressed even in a high temperature environment, and an antistatic layer with excellent flexibility and durability is obtained, making it a desirable form.

In addition, by having an antistatic layer on the surface of the polarizing plate, there is no need to impart antistatic properties to the adhesive layer constituting the surface protection film for the polarizing plate that is directly laminated (in contact) with the antistatic layer, and ultimately, it is necessary to mix the antistatic component. Since it is not necessary, it is preferable because it has excellent stain resistance and good appearance. In particular, by blending the polyaniline sulfonic acid and the polythiophenes doped with the polyanions within the above range, the polyaniline sulfonic acid alone or the polythiophenes doped with the polyanions are blended alone. The reason why antistatic stability in a high-temperature environment is improved compared to other cases is presumed to be as follows. Polythiophenes doped with polyanions form a complex by coordinating polythiophenes with anionic groups of polyanions, and their conduction mechanism is the intramolecular conduction of polythiophenes that occurs in the complex, poly The intermolecular and intercomplex challenges of thiophenes are known. Here, the challenge between complex structures is a rate-limiting process due to the distance between molecules. By using polyaniline sulfonic acid, which is a higher molecular weight than polythiophenes, polyaniline sulfonic acid connects the complexes made of polythiophenes and polyanions and is also conductive, thereby increasing the conductivity between the complexes, improving antistatic properties, and improving high temperature. It is presumed that stability in the environment has increased, making it very useful as a polarizing plate. Additionally, when the polyaniline sulfonic acid is used alone as the conductive polymer, the initial conductivity is low, so the peeling electrification voltage and surface resistance value are likely to increase over time.

In addition, when the polythiophenes doped with the above-mentioned polyanions are used alone, the initial conductivity is high, but the polyanions (equivalent to the dopant) desorb more easily than the polythiophenes over time, causing peeling over time. This is undesirable as it is easy for an increase in charging voltage or surface resistance value to occur.

<Conductive polymer>

The antistatic layer is preferably formed from an antistatic agent composition containing polyanilinesulfonic acid and polythiophene doped with polyanions as a conductive polymer component. By combining the above-mentioned conductive polymers, compared to the case where each of the conductive polymers is combined individually, the conductivity is increased because polyanilinesulfonic acid takes charge of the conduction between the core and shell structures of polythiophenes and polyanions, and the peeling antistatic property based on the antistatic layer is achieved. And it is useful because it can stabilize antistatic properties in a high-temperature environment.

The content of the conductive polymer is preferably 1 to 90% by weight, more preferably 5 to 80% by weight, further preferably 10 to 70% by weight, and most preferably, based on the total components included in the antistatic layer. is 20 to 50% by weight. If the content of the conductive polymer is too small, the antistatic effect may be reduced, and if the content of the conductive polymer is too high, the adhesion of the antistatic layer to the base material (protective film for polarizer) may decrease or transparency may decrease. It is not desirable.

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

Examples of commercially available products of the polyaniline sulfonic acid include the product name “aqua-PASS” manufactured by Mitsubishi Rayon Corporation.

Examples of polythiophenes used as the conductive polymer component include polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), and poly(3). -butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene) , poly (3-octadecylthiophene), poly (3-bromothiophene), poly (3-chlorothiophene), poly (3-iodothiophene), poly (3-cyanothiophene), poly (3 -phenylthiophene), poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly( 3-ethoxythiophene), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly(3-heptyloxythiophene), poly(3-octyloxythiophene), poly(3- Decyloxythiophene), poly(3-dodecyloxythiophene), poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene), poly(3,4-dimethoxythiophene) ), poly(3,4-diethoxythiophene), poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene), poly(3,4-dihexyloxythiophene) , poly (3,4-dihexyloxythiophene), poly (3,4-dioctyloxythiophene), poly (3,4-didecyloxythiophene), poly (3,4-didodecyloxythiophene), Poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butenedioxythiophene), poly(3-methyl-4-methoxythiophene), poly (3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), poly( 3-methyl-4-carboxybutylthiophene). These may be used alone or in mixture of two or more types. Among them, poly(3,4-ethylenedioxythiophene) (PEDOT) is preferable from the viewpoint of conductivity.

As for the polythiophenes, the degree of polymerization is preferably 2 to 1000, more preferably 5 to 100. If it is within the above range, it is preferable because it has excellent conductivity.

The polyanions are polymers of structural units having an anionic group, and act as dopants for polythiophenes. Examples of the polyanions include polystyrenesulfonic acid, polyvinylsulfonic acid, polyallylsulfonic acid, polyacrylsulfonic acid, polymethacrylsulfonic acid, poly(2-acrylamide-2-methylpropanesulfonic acid), polyisoprenesulfonic acid, and polysulfoethyl. Methacrylate, poly(4-sulfobutyl methacrylate), polymethalyloxybenzenesulfonic acid, polyvinylcarboxylic acid, polystyrenecarboxylic acid, polyallylcarboxylic acid, polyacrylcarboxylic acid, polymethacrylcarboxylic acid Acid, poly(2-acrylamide-2-methylpropanecarboxylic acid), polyisoprenecarboxylic acid, polyacrylic acid, polysulfonated phenylacetylene, etc. can be mentioned. These may be homopolymers or two or more types of copolymers. Among them, polystyrene sulfonic acid (PSS) is preferable.

The weight average molecular weight (Mw) of the polyanions is preferably 1,000 to 1,000,000, more preferably 2,000 to 500,000. If it is within the above range, it is preferable because doping and dispersibility for polythiophenes are excellent.

Commercially available products of polythiophenes doped with the above-mentioned polyanions include, for example, poly(3,4-ethylenedioxythiophene)/polystyrenesulfonic acid (PEDOT/PSS) under the trade name “Bytron P” manufactured by BAYER. Examples include the brand name “Sepuljida” manufactured by S Polymer, the brand name “Berazol” manufactured by Soken Chemical Company, and the brand name “Denatron P-502RG” manufactured by Nagase Chemtex. Among them, when PEDOT/PSS is used in the antistatic layer constituting the polarizing plate, the occurrence of contamination is suppressed and contamination resistance is excellent compared to the case where antistatic components are used in the adhesive layer constituting the surface protection film for the polarizing plate, and PEDOT Since /PSS is a conductive polymer, an antistatic layer with excellent flexibility and durability is obtained, making it a desirable form.

The antistatic agent composition has a mixing ratio (weight ratio) of the polyaniline sulfonic acid and the polythiophene doped with the polyaniline (the polyaniline sulfonic acid: the polythiophene doped with the polyanion) of 90. :10 to 10:90 is preferable, more preferably 85:15 to 15:85, and still more preferably 80:20 to 20:80. If it is within the above range, the surface resistance value can be suppressed low, and the stability of the surface resistance value in particular in a high temperature environment is excellent, making it a desirable form. Additionally, when the content of polyaniline sulfonic acid is low or when the content of polythiophenes doped with the polyanions is low, the surface resistance value in a high temperature environment tends to increase, which is not preferable.

<Binder>

The antistatic layer may include a binder component and can be used without particular restrictions, but is formed by an antistatic agent composition containing a polyester resin as a binder in order to provide solvent resistance, mechanical strength, antistatic properties, and thermal stability. desirable. The polyester resin is preferably a resin material containing polyester as a main component (typically more than 50% by weight, preferably more than 75% by weight, for example, more than 90% by weight). The polyesters are typically composed of polyhydric carboxylic acids (typically dicarboxylic acids) having two or more carboxyl groups per molecule and their derivatives (anhydrides, esters, halides, etc. of the polyhydric carboxylic acids). One or two or more types of compounds selected from (polyhydric carboxylic acid component) and one or two or more compounds selected from polyhydric alcohols (typically diols) having two or more hydroxyl groups in one molecule ( It is preferable to have a structure in which polyhydric alcohol component) is condensed.

Examples of compounds that can be employed as the polyhydric carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±)-malic acid, meso-tartaric acid, Itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid, Methyladipic acid, dimethyladipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6- Aliphatic dicarboxylic acids such as tetramethylsuberic acid, azelaic acid, sebacic acid, perfluorosebacic acid, brassylic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid, and tetradecyldicarboxylic acid; Cycloalkyldicarboxylic acids (e.g. 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-(2-norbornene)dicarboxylic acid, 5-cyclohexanedicarboxylic acid, Alicyclic dicarboxylic acids such as norbornene-2,3-dicarboxylic acid (hymic acid), adamantane dicarboxylic acid, and spiroheptane dicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, and methyl Isophthalic acid, dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methyl terephthalic acid, dimethyl terephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorenedicarboxylic acid, anthracenedicarboxylic acid, Biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4''-p-terephenylenedicarboxylic acid, 4,4''-p-kwa Relphenyldicarboxylic acid, bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid, phenylene diacetic acid, phenylene dipropionic acid, naphthalene dicarboxylic acid, naphthalene dipropionic acid, biphenyl diacetic acid, biphenyl dicarboxylic acid Propionic acid, 3,3'-[4,4'-(methylenedi-p-biphenylene)dipropionic acid, 4,4'-bibenzyldiacetic acid, 3,3'(4,4'-bibenzyl)di Aromatic dicarboxylic acids such as propionic acid and oxydi-p-phenylene diacetic acid; acid anhydrides of any of the above-mentioned polyhydric carboxylic acids; esters of any of the above-mentioned polyhydric carboxylic acids (e.g., alkyl esters, monoesters, di esters, etc.); acid halides corresponding to any of the above-mentioned polyvalent carboxylic acids (for example, dicarboxylic acid chloride); and the like.

Suitable examples of compounds that can be employed as the polyhydric carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and their acid anhydrides; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, hymic acid, and 1,4-cyclohexanedicarboxylic acid, and their acid anhydrides; and lower alkyl esters of the above dicarboxylic acids (for example, esters with monoalcohols having 1 to 3 carbon atoms).

On the other hand, examples of compounds 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, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl-1, Diols such as 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A, bisphenol A, etc. can be mentioned. Other examples include alkylene oxide adducts (e.g., ethylene oxide adducts, propylene oxide adducts, etc.) of these compounds.

The molecular weight of the polyester resin is the 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 × It may be about 10 ⁴ to 6×10 ⁴ ). Additionally, the glass transition temperature (Tg) of the polyester resin may be, for example, 0 to 120°C (preferably 10 to 80°C).

Commercially available products of the polyester resin include, for example, Toyobo Co., Ltd. under the trade names Vilonal MD-1100, MD-1200, MD-1245, MD-1335, MD-1480, MD-1500, MD-1930, and MD-1985. , MD-2000, brand name Plascoat Z-221, Z-446, Z-561, Z-565, Z-880, Z-3310, RZ-105, RZ-570, Z-730 manufactured by Koh Kagaku Kogyo Co., Ltd. , Z-760, Z-592, Z-687, Z-690, pes resin A-110, A-120, A-124GP, A-125S, A-160P, A-520, A- manufactured by Takamatsu Yushi Co., Ltd. Examples include 613D, A-615GE, A-640, A-645GH, A-647GEX, A-680, A-684G, WAC-14, WAC-17XC, etc.

The antistatic layer may contain a resin other than polyester resin (e.g., acrylic resin, acrylic-urethane resin, (one or two 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, polyolefin resin, etc.) It is also possible to use When using the above resins in combination, an antistatic layer in which the proportion of polyester resin in the binder is 51 to 100% by weight is preferable. The proportion of the binder in the entire antistatic layer can be, for example, 50 to 95% by weight, and usually 60 to 90% by weight is appropriate.

<Active>

The antistatic agent composition used when forming the antistatic layer in the technology disclosed herein uses at least one type selected from the group consisting of fatty acid amide, fatty acid ester, silicone-based lubricant, fluorine-based lubricant and wax-based lubricant as a lubricant. This is the preferred form. By using the above-mentioned lubricant, sufficient slipperiness can be achieved even in a form in which the surface of the antistatic layer is not subjected to additional peeling treatment (for example, a treatment of applying a known peeling treatment agent such as a silicone-based release agent or a long-chain alkyl-based release agent and drying it). This can be a desirable form because an antistatic layer that achieves both print adhesion can be obtained. In this way, in the form in which no additional peeling treatment is applied to the surface of the antistatic layer, whitening caused by the peeling treatment agent (for example, whitening due to storage under heating and humidification conditions) can be prevented in advance. desirable. It is also advantageous from the viewpoint of solvent resistance.

Specific examples of the fatty acid amides 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, and N-stearyl. Stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis laur Acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylenehydroxystearic acid amide, N, N'- Distearyl adipic acid amide, N, N'-distearyl sebacic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N, N'-dioleyl adipic acid amide, N ,N'-dioleylsebacic acid amide, m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-stearyl isophthalic acid amide, etc. These lubricants may be used individually or in combination of two or more types.

Specific examples of the fatty acid esters include polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, behenate monoglyceride, cetyl 2-ethylhexanoate, and myrist. Isopropyl acid, isopropyl palmitate, cholesteryl isostearate, lauryl methacrylate, methyl palm fatty acid, methyl laurate, methyl oleate, methyl stearate, myristyl myrstate, octyldodecyl myrstate. , pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, isotridecyl stearate, 2-ethylhexanoate triglyceride, butyl laurate, octyl oleate, etc. I can hear it. These lubricants may be used individually or in combination of two or more types.

Specific examples of the silicone-based lubricant include polydimethylsiloxane, polyether-modified polydimethylsiloxane, amino-modified polydimethylsiloxane, epoxy-modified polydimethylsiloxane, carbinol-modified polydimethylsiloxane, mercapto-modified polydimethylsiloxane, carboxyl-modified polydimethylsiloxane, Methyl hydrogen silicone, methacrylic modified polydimethylsiloxane, phenol modified polydimethylsiloxane, silanol modified polydimethylsiloxane, aralkyl modified polydimethylsiloxane, fluoroalkyl modified polydimethylsiloxane, long chain alkyl modified polydimethylsiloxane, higher fatty acid modified. Examples include ester-modified polydimethylsiloxane, higher fatty acid amide-modified polydimethylsiloxane, and phenyl-modified polydimethylsiloxane. These lubricants may be used individually or in combination of two or more types.

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

Specific examples of the wax-based lubricant include petroleum wax (paraffin wax, etc.), vegetable wax (carnauba wax, etc.), mineral wax (montan wax, etc.), higher fatty acid (cerotic acid, etc.), neutral fat (triglyceride palmitic acid, etc.) Various waxes such as ceride, etc. can be mentioned. These lubricants may be used individually or in combination of two or more types.

The proportion of the lubricant in the entire antistatic layer can be 1 to 50% by weight, and usually 5 to 40% by weight is appropriate. If the content ratio of the lubricant is too small, the slipperiness tends to decrease easily. If the lubricant content is too high, print adhesion or back peeling force (adhesion) may decrease.

The antistatic agent composition forming the antistatic layer preferably contains, as a crosslinking agent, at least one selected from the group consisting of a silane coupling agent, an epoxy-based crosslinking agent, a melamine-based crosslinking agent, and an isocyanate-based crosslinking agent, and among these, the melamine-based crosslinking agent is particularly preferred. It is a preferred form by using a cross-linking agent and/or an isocyanate-based cross-linking agent. When forming an antistatic layer, a conductive polymer component (for example, polyaniline sulfonic acid or polythiophene doped with polyanions) can be immobilized in the binder, resulting in excellent water resistance and solvent resistance, as well as improved print adhesion, etc. The effect can be realized. In particular, water resistance and solvent resistance are improved by using a melamine-based crosslinking agent, water resistance and print adhesion are improved by using an isocyanate-based crosslinking agent, and water resistance, solvent resistance, and print adhesion are improved and useful by using these crosslinking agents in combination.

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

Additionally, as the isocyanate-based crosslinking agent, it is preferable to use a blocked isocyanate-based crosslinking agent that is stable even in aqueous solutions. Specific examples of the blocked isocyanate-based crosslinking agent include isocyanate-based crosslinking agents that can be used in the production of general adhesive layers and antistatic layers, including alcohols, phenols, thiophenols, amines, imides, oximes, lactams, and activated methylene compounds. , mercaptans, imines, ureas, diaryl compounds, sodium bisulfite, etc. can be used.

The antistatic layer in the technology disclosed herein may optionally contain antistatic agents, antioxidants, colorants (pigments, dyes, etc.), fluidity modifiers (thixotropic agents, thickeners, etc.), film forming aids, surfactants (defoamer, etc.), It may contain additives such as preservatives. Additionally, it is possible to contain glycidyl compounds, polar solvents, polyhydric aliphatic alcohols, lactam compounds, etc. as conductivity improvers.

<Formation of antistatic layer>

The antistatic layer is a liquid composition (coating material for forming an antistatic layer, antistatic agent composition) in which additives used according to the conductive polymer component are dissolved or dispersed in an appropriate solvent (water, etc.) and applied to the substrate (protective film for polarizer). It can be suitably formed by a method including. For example, a method of applying the above-mentioned coating material to one side of a base material (protective film for polarizer), drying it, and performing a hardening treatment (heat treatment, ultraviolet treatment, etc.) as necessary can be preferably adopted. The NV (non-volatile matter) of the coating material can 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). It is appropriate to do so. When forming an antistatic layer with a small thickness, it is preferable that the NV of the coating material is, for example, 0.05 to 0.50% by weight (for example, 0.10 to 0.40% by weight). In this way, a more uniform antistatic layer can be formed by using a low NV coating material.

The solvent constituting the coating material for forming the antistatic layer is preferably one that can stably dissolve or disperse the components for forming the antistatic layer. This solvent may be an organic solvent, water, or a mixed solvent 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 ether (for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) and dialkylene glycol monoalkyl ether; One or two or more types selected from the like can be used. In a preferred form, the solvent for the coating material is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol).

Additionally, in order to improve dispersion stability in solvents, it is possible to include a basic organic compound capable of coordinating or bonding as an ion pair to an anionic group of polyanions. Examples of basic organic compounds include known amine compounds, hydrochloride salts of amine compounds, cationic emulsifiers, and basic resins.

Specifically, the basic organic compounds include methyloctylamine, methylbenzylamine, N-methylaniline, dimethylamine, diethylamine, diethanolamine, N-methylethanolamine, di-n-propylamine, and diisopropylamine. , methyl-isopropanolamine, dibutylamine, di-2-ethylhexylamine, aminoethylethanolamine, 3-amino-1-propanol, isopropylamine, monoethylamine, 2-ethylhexylamine, t-butylamine, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltri Amine compounds such as ethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane, monomethylamine, monoethylamine, and stearylamine. Hydrochloride salts of primary amines such as dimethylamine, diethylamine, distearylamine, etc., hydrochlorides of tertiary amines such as trimethylamine, triethylamine, and stearyldimethylamine, and stearyltrimethylammonium. Quaternary ammonium salts such as chloride, distearyldimethylammonium chloride, and stearyldimethylbenzylammonium chloride; hydrochlorides of ethanolamines such as monoethanolamine, diethanolamine, and triethanolamine; and polyethylenepolyamines such as ethylenediamine and diethylenetriamine. Hydrochloride salts, etc. can be mentioned.

Specific examples of the cationic emulsifier include alkylammonium salt, alkylamide betaine, and alkyldimethylamine oxide.

Specific examples of the basic resin include those made of polyester-based, acrylic-based, and urethane-based polymer copolymers and having a weight average molecular weight (Mw) of 10 million to 1 million. If the weight average molecular weight of the basic resin is less than 1000, sufficient steric hindrance may not be obtained and the dispersion effect may be reduced, and even if the weight average molecular weight is greater than 1 million, conversely, aggregation may occur.

Additionally, the amine value of the basic resin is preferably 5 to 200 mgKOH/g. If it is less than 5 mgKOH/g, the interaction with polyanions doped with polythiophene tends to become insufficient, and a sufficient dispersion effect may not be obtained. On the other hand, when the amine value of the basic resin exceeds 200 mgKOH/g, the steric hindrance layer decreases compared to the affinity portion for polyanions doped with polythiophene, and the dispersion effect may become insufficient.

Examples of the basic resin include Solsperse 17000, Solsperse 20000, Solsperse 24000, Solsperse 32000 (manufactured by Zeneca Corporation), Disperbyk-160, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk-170, and Disperbyk-2000. , Disperbyk-2001 (manufactured by Big Chemistry), Azisper PB711, Azisper PB821, Azisper PB822, Azisper PB824 (manufactured by Ajinomoto Co., Ltd.), Eformin 006, Eformin 012, Eformin 018 (Nippon Shokubai Gabu) (manufactured by Shikigaisha), EFKA 4046, EFKA 4300, EFKA 4330, EFKA 4510 (manufactured by EFKA), and Disphalon DA-400N (manufactured by Kusumoto Kasei Kagaku), etc., and can be used alone or in combination. In particular, AZISPER PB821, AZISPER PB822, and AZISPER PB824 are preferable from the viewpoint of dispersibility and conductivity during use.

There is no limitation on the content of the basic compound, but it is preferably in the range of 1 to 100,000 parts by weight, more preferably in the range of 10 to 10,000 parts by weight, based on a total of 100 parts by weight of polythiophenes and polyanions. It can be added.

<Properties of antistatic layer>

The thickness of the antistatic layer (after heat stretching) is preferably 100 nm or less, more preferably 3 to 100 nm, and even more preferably 20 to 80 nm. If the thickness of the antistatic layer is too small, it becomes difficult to form the antistatic layer uniformly (for example, the variation in the thickness of the antistatic layer depending on the location increases), and therefore, stains are likely to occur on the exterior of the polarizer. You can. On the other hand, if it is too thick, it may affect the characteristics of the polarizing plate (optical characteristics, dimensional stability, etc.).

The surface resistance value (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 even more preferably 1.0×10 ⁶ to 1.0×10 ⁷ . A polarizing plate having a surface resistance value within the above range suppresses electrification of the surface protection film for polarizing plates due to frictional electrification occurring during the processing or conveyance process, and prevents it from attracting dust or deteriorating workability. It becomes possible and can be used appropriately. Additionally, the surface resistance value can be calculated from the surface resistance value measured in an atmosphere of 23°C and 50% RH humidity using a commercially available insulation resistance measuring device.

<First adhesive layer>

A structure in which a first adhesive layer is laminated on at least one side of the polarizing plate can be used, and another optical member (for example, a retardation film or liquid crystal display devices, etc.) can be laminated (see Figure 2). An appropriate adhesive (adhesive composition) can be used in the first adhesive layer, and there is no particular limitation on its type. Examples of adhesives include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives. Among these adhesives (adhesive compositions), those that are excellent in optical transparency, exhibit appropriate adhesive properties of wettability, cohesiveness and adhesiveness, and are excellent in weather resistance, heat resistance, etc. are preferably used. An acrylic adhesive that exhibits these characteristics is preferably used.

As a method of forming the first adhesive layer, for example, the adhesive (adhesive composition) is applied to a separator that has been peeled, the polymerization solvent is dried and removed to form an adhesive layer, and then transferred to a polarizing plate. It is manufactured by applying the adhesive, drying and removing the polymerization solvent, etc. to form an adhesive layer on the polarizer. In addition, when applying the adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate. As the separator subjected to the peeling treatment, a silicone separator is preferably used.

In the process of forming an adhesive layer by applying and drying the adhesive (adhesive composition) on such a separator, an appropriate method may be adopted as a method of drying the adhesive depending on the purpose. Preferably, a method of heating and drying the coating film is used. The heat drying temperature is preferably 40 to 200°C, more preferably 50 to 180°C, and particularly preferably 70 to 170°C. By keeping the heating temperature within the above range, an adhesive layer with excellent adhesive properties can be obtained.

Various methods are used as a method of forming the adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Methods such as an extrusion coating method can be mentioned.

The thickness of the first adhesive layer is preferably 2 to 50 μm, more preferably 2 to 40 μm, and still more preferably 5 to 35 μm.

The separator can protect the first adhesive layer until it is put to practical use. As the constituent material of the separator, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and non-woven fabric, and suitable materials such as nets, foam sheets, metal foil, and laminates thereof. Examples include thin foils, but plastic films are suitably used because they have excellent surface smoothness. The plastic film is not particularly limited as long as it is a film that can protect the adhesive layer, and examples include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, and vinyl chloride. Examples include copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, and ethylene-vinyl acetate copolymer films.

If necessary, the separator can also be subjected to mold release and antifouling treatment using silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, silica powder, etc., or antistatic treatment such as coating type, paste type, or vapor deposition type. In particular, by appropriately performing a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the release film, the peelability from the first adhesive layer can be further improved.

The thickness of the separator is usually preferably 5 to 50 μm, and more preferably 15 to 40 μm.

The polarizing plate disclosed herein may be implemented in a form that further includes other layers in addition to the antistatic layer, the protective film for polarizer, the polarizer, and the intervening layer (adhesive layer, first pressure-sensitive adhesive layer, etc.).

<Polarizing plate with surface protection film for polarizing plate>

The polarizing plate having the surface protection film of the present invention includes the polarizing plate, the surface protection film for the polarizing plate, and the surface protection film for the polarizing plate being laminated on the antistatic layer of the polarizing plate through the adhesive layer of the surface protecting film for the polarizing plate. It is characterized by having The polarizing plate having the surface protection film of the present invention has a specific configuration (stacking order), so that when the surface protection film for polarizing plate is peeled off after use by laminating (attaching) this polarizing plate to a liquid crystal display (LCD) or the like, the polarizing plate is used as a polarizing plate. Since the antistatic layer constituting the antistatic protective film and the antistatic layer constituting the polarizing plate are located at a specific position (order of stacking), whitening of panels such as liquid crystal displays and destruction of tags can be prevented, and peeling antistatic properties are possible. Excellent and useful. In addition, the adhesive layer has excellent contamination resistance by not using an antistatic component, and has excellent flexibility and durability (scratch resistance) by having an antistatic layer constituting the polarizing plate, making it useful.

[Example]

Hereinafter, several examples related to the present invention will be described, but it is not intended to limit the present invention to those shown by these specific examples. In addition, “part” and “%” in the following description are based on weight, unless otherwise specified. Additionally, the mixing amount (additional amount) in the table is shown.

In addition, each characteristic in the description below was measured or evaluated as follows. In addition, about the preparation method of the polarizing plate described below, the surface protection film for polarizing plates, and the polarizing plate having the surface protection film for polarizing plates, it was prepared according to the structure, positional relationship, etc. described in Table 1.

<Preparation of protective film for polarizer>

Acrylic resin (brand name: Acrypet VH, Tg: 113°C, manufactured by Mitsubishi Rayon Co., Ltd.) was vacuum dried at 100°C to remove moisture and residual oxygen. A mixture of 100 parts by weight of deaerated acrylic resin and 30 parts by weight of acrylic rubber (Product name: AR12, manufactured by Nippon Zeon Co., Ltd.) was purged with nitrogen from the raw material hopper to the extruder using a twin-screw extruder (Device name: TEM35B, Toshiba Kikai ( It was supplied to Co., Ltd., melted at a cylinder set temperature of 230 to 270°C, and pelletized to obtain raw material pellets. The obtained raw material pellets are vacuum dried at 100°C, supplied to a single-screw extruder (equipment name: SE-65, manufactured by Toshiba Kikai Co., Ltd.) purged with nitrogen from the raw material hopper to the extruder, and melted at 230 to 270°C in a cylinder set. After passing through a coat hanger type T die and cooling in a chrome-plated casting roll at 120°C and a cooling chrome-plated casting roll at 90°C, an acrylic resin film (thickness: 40㎛) is used as a protective film for a polarizer in a film winding device. ) was obtained.

<Preparation of protective film for polarizer having antistatic layer (polymer type)>

Denatron P-502RG (containing PEDOT/PSS) manufactured by Nagase Chemtex, an antistatic agent composition, was applied onto the acrylic resin film (thickness: 40㎛), which is the protective film for the polarizer, using wire bar #6, and then heated at 120°C. was dried for 60 seconds to produce 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 3.12×10 ⁶ Ω/□.

<Preparation of protective film for polarizer having antistatic layer (metal type)>

On the acrylic resin film (thickness: 40 μm), which is the protective film for the polarizer, tin-based oxide S-1, manufactured by Mitsubishi Material Electronics Chemicals, which is an antistatic agent composition, was applied using wire bar #6, and then applied at 120°C. It was dried for 60 seconds to produce 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 1.21×10 ⁶ Ω/□.

<Production of polarizer>

A 75㎛ thick polyvinyl alcohol film (degree of polymerization: 2300, degree of saponification: 99.9%, width: 1000mm, thickness: 75㎛, manufactured by Kuraray Co., Ltd.: VF-PS7500) was immersed in pure water at 30°C for 60 seconds. It was stretched up to a stretching ratio of 2.5 times.

Next, dyeing was performed for 45 seconds in an iodine aqueous solution at 30°C (weight ratio: pure water/iodine (I)/potassium iodide (KI)=100/0.01/1).

After that, it was stretched in a 4% by weight boric acid aqueous solution so that the stretching ratio was 5.8 times. After stretching, the film was immersed in pure water for 10 seconds and then dried at 50°C for 3 minutes while maintaining the tension of the film to obtain a polarizer. The thickness of this polarizer was 25㎛, and the moisture content was 14% by weight.

<Preparation of adhesive aqueous solution>

100 parts by weight of a polyvinyl alcohol-based resin containing an acetoacetyl group (average degree of polymerization: 1200, degree of saponification: 98.5 mol%, degree of acetoacetyl group modification: 5 mol%) and 50 parts by weight of methylolmelamine in pure water (water temperature: 30°C). An aqueous solution was prepared by dissolving it in and adjusting the solid content to 3.7% by weight. An aqueous adhesive solution was prepared by adding 18 parts by weight of alumina colloid aqueous solution (average particle diameter: 15 nm, solid content concentration: 10% by weight, positive charge) to 100 parts by weight of the aqueous solution. The viscosity of the adhesive aqueous solution was 9.6 mPa·s. The pH of the adhesive aqueous solution ranged from 4 to 4.5. This was used as an adhesive aqueous solution.

<Laminate the antistatic layer of the polarizing plate on the adhesive layer side of the surface protection film for polarizing plate (side of the surface protective film for polarizing plate)>

The adhesive aqueous solution was applied to the surface opposite to the antistatic layer of the protective film for a polarizer with an antistatic layer so that the thickness of the adhesive layer after drying was about 55 nm, thereby producing a protective film for a polarizer with an adhesive layer.

Thereafter, under a temperature condition of 23°C, the protective film for a polarizer having the adhesive layer is bonded to one side of the polarizer with a roll so that the adhesive layer of the protective film for a polarizer having the adhesive layer is in contact with the polarizer. This was used to make a laminate. The laminate was dried at 70°C for 10 minutes to produce a polarizing plate (1).

<Laminate the polarizer of the polarizing plate on the adhesive layer side of the surface protection film for the polarizing plate (polarizer side)>

The adhesive aqueous solution was applied to the surface of the antistatic layer of the protective film for a polarizer having an antistatic layer so that the thickness of the adhesive layer after drying was about 55 nm, thereby producing a protective film with an adhesive layer.

Thereafter, under a temperature condition of 23°C, the protective film for a polarizer having the adhesive layer is bonded to one side of the polarizer with a roll so that the adhesive layer of the protective film for a polarizer having the adhesive layer is in contact with the polarizer. This was used to make a laminate. The laminate was dried at 70°C for 10 minutes to produce a polarizing plate (2).

<Preparation of a polarizing plate in which the protective film for a polarizer of a polarizing plate without an antistatic layer is laminated on the adhesive layer side of the surface protective film for a polarizing plate>

With respect to the polarizer protective film having an antistatic layer of the polarizing plate 1, the adhesive aqueous solution is applied to one side of the polarizer protective film without an antistatic layer so that the thickness of the adhesive layer after drying is about 55 nm, forming an adhesive layer. A protective film for a polarizer having a was produced.

Thereafter, under a temperature condition of 23° C., the protective film for a polarizer having the adhesive layer is bonded to one side of the polarizer with a roll so that the adhesive layer of the protective film for a polarizer having the adhesive layer is in contact with the polarizer. This was used to make a laminate. The laminate was dried at 70°C for 10 minutes to produce a polarizing plate (3).

<Surface protection film for polarizer used>

<E-MASK RP207>

As a surface protection film for polarizing plates, the brand name "E-MASK RP207" manufactured by Nitto Denko Co., Ltd. with the composition shown in Table 1 was used.

<AS3-830>

As a surface protection film for polarizing plates, the brand name "AS3-830" manufactured by Fujimori Kogyo Co., Ltd. and having the composition shown in Table 1 was used.

<NSA35-H>

As a surface protection film for a polarizing plate, the brand name "Sunnytect NSA35-H" manufactured by Sun A Gaken Co., Ltd. with the composition shown in Table 1 was used.

<Production of a polarizing plate having a surface protection film for a polarizing plate>

The surface where the antistatic layer of the polarizer (1) manufactured above is exposed, or the surface where the polarizer of the polarizer (2) is exposed, or the protective film for the polarizer of the polarizer (3) without the antistatic layer is exposed. The surface of the adhesive layer of the surface protection film for polarizing plates was bonded to the surface with a roller and left at room temperature for 5 minutes to produce a polarizing plate with a surface protection film for polarizing plates.

<Measurement of surface resistance value of antistatic layer surface of polarizing plate>

Measurements were made according to JIS-K-6911 using a resistivity meter (Hiresta UP MCP-HT450 type, manufactured by Mitsubishi Chemical Analytech) in an atmosphere of a temperature of 23°C 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.

Additionally, the surface resistance value (Ω/□) measured on the surface of the antistatic layer of the polarizing plate was measured with the antistatic layer formed after applying and drying the antistatic agent composition (solution) to the base film.

In addition, the surface resistance value (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 , and even more preferably is 1.0×10 ⁶ to 1.0×10 ⁷ . The surface protection film for a polarizing plate having an antistatic layer showing a surface resistance value within the above range can be suitably used as a surface protection film used in the processing or conveyance process of articles that are resistant to static electricity, such as liquid crystal cells or semiconductor devices, for example. You can.

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

As shown in FIG. 3, the surface protection film 2 for a polarizing plate according to each example is cut to a size of 70 mm in width and 130 mm in length, the release liner is peeled from the surface of the adhesive layer, and then the acrylic film has been previously destaticized. The polarizing plate 3 (width: 70 mm, length: 100 mm) was bonded to the plate 31 (manufactured by Mitsubishi Rayon, brand name: "Acrylite", thickness: 1 mm, width: 70 mm, length: 100 mm). On the surface of 100 mm), one end of the surface protection film for polarizing plate 2 was made to protrude 30 mm from the end of the polarizing plate 20, and was pressed with a hand roller through an adhesive layer to prepare a sample.

This sample was left in an environment of 23° C. The end of the surface protection film 1, which protruded 30 mm from the polarizing plate 3, was fixed to an automatic winder (not shown) and peeled at a peeling angle of 150° and a peeling speed of 30 m/min. The potential on the surface of the adherend (polarizing plate) generated at this time is measured by measuring the potential on the surface of the adherend (polarizing plate) 32 (model "KSD-0103" manufactured by Kasuga Denki Co., Ltd.) fixed at a position of 100 mm in height from the center of the polarizing plate 20. The charging voltage was measured. Measurements were conducted in an environment of 23°C and 50%RH. In addition, when the polarizing plate did not have an antistatic layer, the surface potential of the protective film for polarizer was measured instead of the surface of the antistatic layer as the peeling electrification voltage.

In addition, the peeling electrification voltage is a peeling electrification voltage mainly derived from the antistatic layer constituting the surface protection film for polarizing plates of the present invention, and contributes to the peeling antistatic property.

The peeling charge voltage (absolute value) of the surface protection film for polarizing plates 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 arrangement of the polarizers in the polarizing plate is disturbed, which is not preferable. In addition, as an evaluation in Table 1, 0.4 kV or less was evaluated as ○ (good), and if it exceeded 0.4 kV, it was evaluated as × (recessive).

<Contamination resistance>

After attaching the surface of the adhesive layer of the surface protection film for a polarizing plate to the surface of the antistatic layer of the polarizing plate and holding it at 70°C for 120 hours, the presence or absence of contamination on the surface of the polarizing plate after peeling the surface protective film for a polarizing plate from the polarizing plate at a peeling speed of 30 m/min. It was confirmed by visual inspection. In addition, when the surface of the polarizing plate to which the surface of the adhesive layer of the surface protective film for polarizing plates is attached is not an antistatic layer but a protective film for polarizers, the presence or absence of contamination on the surface of the protective films for polarizers was visually confirmed.

As an evaluation, cases where contamination was not confirmed were evaluated as ○ (good), and cases where contamination was confirmed were evaluated as × (poor).

<Steel wool test (durability)>

Steel wool (#0000, manufactured by Nippon Steel Wool Co., Ltd.) was attached to a circular jig with a radius of 25 mm and the scratch resistance (durability) of the surface of the antistatic layer was evaluated under the condition of making 5 reciprocations of 10 cm in length with a load of 10 g. did. Cases where the number of visually confirmed defects was 10 or less were evaluated as ○ (good), and cases where the number exceeded 10 were evaluated as × (recessive). In addition, when the surface of the polarizing plate to which the surface of the adhesive layer of the surface protection film for polarizing plates is attached is not an antistatic layer, durability is not evaluated.

Regarding the polarizing plate having the surface protection film for polarizing plate according to the Examples and Comparative Examples, the above-described formulation details and the results of various measurements and evaluations are shown in Table 1.

Note) The “polymer type” in Table 1 refers to the use of a conductive polymer (PEDOT/PSS) as an antistatic component, and the metal type refers to the use of tin-based oxide as an antistatic component.

In addition, "the surface protection film side for polarizing plates" in Table 1 refers to the case where the adhesive layer surface of the surface protection film for polarizing plates contacts the exposed surface of the antistatic layer on the opposite side to a polarizer.

“Polarizer side” refers to the case where the adhesive layer surface of the surface protection film for polarizing plates contacts the exposed surface of the polarizer on the opposite side to the protective film for polarizers.

Additionally, if the antistatic layer of the polarizer does not exist, durability is not evaluated.

From Table 1, it was confirmed that in Example 1, the polarizing plate and the surface protection film for polarizing plates had an antistatic layer at a specific position, thereby providing excellent peeling antistatic properties, stain resistance, and durability (scratch resistance).

On the other hand, from Table 1, in the comparative example, when there is no position of the antistatic layer constituting the polarizing plate or the antistatic layer constituting the polarizing plate or the surface protection film for polarizing plate, the peeling antistatic property is poor, and the antistatic layer constituting the polarizing plate is poor. If the position of is not in the desired position, durability is low, and even in the case of an antistatic layer using a metal-type antistatic component, durability is poor, and if the adhesive layer that makes up the surface protection film for a polarizing plate contains an antistatic component, It was confirmed that contamination resistance was low.

The surface protection film constituting the polarizing plate having the surface protection film disclosed herein is suitable for use as a polarizing plate used as a component of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescence (EL) display, etc. You can.

1: Polarizing plate with surface protection film for polarizing plate
2: Surface protection film for polarizer
3: Polarizer
10: Antistatic layer
11: Base film
12: Adhesive layer
20: Antistatic layer
21: Protective film for polarizer
22: Polarizer
23: First adhesive layer
24: Phase contrast film
30: sample fixture
31: Acrylic plate
32: Potential meter

Claims (3)

A polarizing plate having a polarizer and a protective film for a polarizer on at least one side of the polarizer, and having an antistatic layer formed of an antistatic agent composition containing a conductive polymer on the side of the protective film for the polarizer opposite to the side in contact with the polarizer, and ,
A polarizing plate having a surface protection film for a polarizing plate having a base film and a surface protection film for a polarizing plate having an adhesive layer on one side of the base film and having an antistatic layer on the side opposite to the side in contact with the adhesive layer of the base film,
The surface protection film for the polarizing plate is laminated on the antistatic layer of the polarizing plate through the adhesive layer of the surface protecting film for the polarizing plate,
A polarizing plate having a surface protection film for a polarizing plate, characterized in that the adhesive composition forming the adhesive layer does not contain an antistatic component. The method of claim 1, wherein the protective film for polarizer is formed of at least one type of resin selected from the group consisting of (meth)acrylic resin, cyclic olefin resin, polyester resin, and polycarbonate resin. A polarizing plate having a surface protection film for a polarizing plate, characterized in that. The polarizing plate having a surface protection film for a polarizing plate according to claim 1 or 2, wherein the protective film for a polarizer has an ultraviolet ray absorption function.