JP2020003675A - Adhesive composition, surface protection film, and optical film - Google Patents

Abstract

To provide an adhesive composition for reflective polarizing films, which offers superior peeling electrification with reflective polarizing films and can be used for surface protection films dedicated for use with reflective polarizing films.SOLUTION: An adhesive composition for reflective polarizing films is provided, containing an ionic compound adapted to be liquid at room temperature (25°C) and to exhibit viscosity (25°C) of 550 mPa s, and an adhesive polymer.SELECTED DRAWING: None

Description

  The present invention relates to a pressure-sensitive adhesive composition, a surface protection film, and an optical film.

  The pressure-sensitive adhesive composition for a reflective polarizing film of the present invention can be used for a surface protective film for a reflective polarizing film used for protecting the surface of the reflective polarizing film used for a liquid crystal display or the like, and is useful. It is.

  2. Description of the Related Art In recent years, when transporting optical components and electronic components and mounting them on a printed circuit board, individual components are transported in a state of being wrapped in a predetermined sheet or in a state of sticking an adhesive tape. Among them, surface protective films are widely used particularly in the field of optical and electronic components.

  The surface protection film is generally bonded to a protected object via an adhesive layer applied to the base film side, and is used for the purpose of preventing scratches and stains generated during processing and transport of the protected object (Patent Reference 1). For example, a panel of a liquid crystal display is formed by bonding an optical film such as a polarizing film or a reflective polarizing film (for example, a brightness enhancement film) to a liquid crystal cell via an adhesive layer. In these optical films, a surface protective film is bonded via an adhesive layer to prevent scratches and stains generated during processing and transport of the protected object.

  In particular, in recent years, the integration of optical films has been progressing, and the reflection type polarizing film has been integrated with an optical film such as a polarizer or a polarizing film via an adhesive layer or an adhesive layer to form a liquid crystal display panel. It may be used by pasting it on.

  A reflective polarizing film (e.g., a brightness enhancement film) is an optical film having a function of transmitting polarized light orthogonal to the direction of its reflection axis and reflecting parallel polarized light, and is formed of a material having a different refractive index anisotropy. In this case, a multilayer structure is used in which thin films are alternately laminated.

  Until the reflective polarizing film is integrated with the polarizing film, when using a polarizing film with a reflective polarizing film for a panel, a surface protective film is applied to the surface of the reflective polarizing film via an adhesive layer. It is attached, but then, when the surface protective film is no longer needed, it is charged with static electricity when peeled off from the reflective polarizing film, and when used for a panel, whitening of the panel occurs, lowering the inspection efficiency Cause a problem. In particular, when the reflective polarizing film has a multilayer structure, it is easily charged, which is a problem.

  In recent years, the use of an alkali metal salt, which is an antistatic agent, for the pressure-sensitive adhesive layer constituting the surface protective film has been improved to improve the antistatic property of peeling.For example, when the surface protective film is peeled from the polarizing film, the panel is Attempts have been made to suppress the whitening phenomenon. However, even when the antistatic peeling property can be imparted to the polarizing film, the whitening phenomenon of the panel cannot be prevented for the reflective polarizing film formed by the multilayer structure that is easily charged. is the current situation.

JP 2017-203167 A

  Therefore, development of a surface protection film that can protect not only the polarizing film but also the surface of the reflective polarizing film formed by the multilayer structure is demanded.

  Therefore, an object of the present invention is to solve the problems with the conventional reflective polarizing film, and to provide a reflective polarizing film that can be used as a surface protective film having excellent antistatic properties for peeling-off polarizing film. It is an object of the present invention to provide a pressure-sensitive adhesive composition for a polarizing film.

  That is, the pressure-sensitive adhesive composition for a reflective polarizing film of the present invention exhibits a liquid at room temperature (25 ° C.) and an ionic compound having a viscosity (25 ° C.) of 550 mPa · s or less, and a pressure-sensitive adhesive polymer. It is characterized by containing.

  In the pressure-sensitive adhesive composition for a reflective polarizing film of the present invention, the pressure-sensitive adhesive polymer may be at least one selected from the group consisting of a (meth) acryl-based polymer, a urethane-based polymer, and a silicone-based polymer. preferable.

  The pressure-sensitive adhesive composition for a reflective polarizing film of the present invention preferably contains a silicone component.

  The surface protective film for a reflective polarizing film of the present invention preferably has an adhesive layer formed of the adhesive composition for a reflective polarizing film on at least one surface of the substrate film.

  The optical film of the present invention preferably has the surface protective film for a reflective polarizing film and a reflective polarizing film.

  The present invention can provide a pressure-sensitive adhesive composition for a reflective polarizing film that can be used for a surface protective film specialized for use in a reflective polarizing film having excellent antistatic properties for peeling off the reflective polarizing film, Useful.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic sectional drawing of the polarizing film with a reflective polarizing film to which the surface protective film which concerns on embodiment of this invention was stuck. The schematic block diagram of the electric potential measurement part used for the measurement of peeling charge voltage in an Example etc.

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

<Overall structure of surface protection film>
The surface protective film disclosed herein is generally in the form of a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive tape, a pressure-sensitive adhesive label, a pressure-sensitive adhesive film, and the like. It is suitable as a surface protection film for protecting the surface. The pressure-sensitive adhesive layer in the surface protection film is typically formed continuously, but is not limited to such a form.For example, it is formed in a regular or random pattern such as a dot shape, a stripe shape, and the like. It may be an adhesive layer. Further, the surface protective film disclosed herein may be in the form of a roll or a single sheet.

<Base film>
The surface protective film for a reflective polarizing film of the present invention (hereinafter sometimes simply referred to as “surface protective film”) preferably has a base film. In the technology disclosed herein, the resin material constituting the base film can be used without any particular limitation. For example, transparency, mechanical strength, heat stability, moisture shielding property, isotropic property, It is preferable to use one having excellent properties such as flexibility and dimensional stability. In particular, since the base film has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like and can be wound into a roll, which is useful.

  Examples of the base film include polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polybutylene terephthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate polymers; polymethyl methacrylate and the like. An acrylic polymer; a plastic film composed of a resin material containing a cycloolefin-based polymer or the like as a main resin component (a main component of the resin component, typically a component occupying 50% by weight or more); It can be preferably used as a film. Other examples of the resin material include styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer; olefin-based polymers such as polyethylene, polypropylene, polyolefin having a cyclic or norbornene structure, and ethylene-propylene copolymer; Examples of the resin material include vinyl chloride-based polymers; amide-based polymers such as nylon 6, nylon 6,6, and aromatic polyamide. Still other examples of the resin material include an imide polymer, a sulfone polymer, a polyether sulfone polymer, a polyether ether ketone polymer, a polyphenylene sulfide polymer, a vinyl alcohol polymer, a vinylidene chloride polymer, and a vinyl butyral polymer. Allylate polymers, polyoxymethylene polymers, epoxy polymers and the like. A base film composed of a blend of two or more of the above-mentioned polymers may be used.

  As the base film, a plastic film made of a transparent thermoplastic resin material can be preferably used. It is a more preferable embodiment to use a polyester film among the plastic films. Here, the polyester film refers to a film mainly containing a polymer material (polyester resin) having a main skeleton based on an ester bond, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polybutylene terephthalate. Say. Such a polyester film has preferable characteristics as a base film of a surface protective film, such as excellent optical properties and dimensional stability, but has a property of being easily charged as it is.

  Various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, and a colorant (eg, a pigment or a dye) may be added to the resin material constituting the base film, if necessary. For example, a known or commonly used surface treatment such as a corona discharge treatment, a plasma treatment, an ultraviolet irradiation treatment, an acid treatment, an alkali treatment, and application of a primer may be applied. Such a surface treatment may be, for example, a treatment for increasing the adhesion between the base film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

  In the surface protective film of the present invention, a plastic film which has been subjected to an antistatic treatment can be used as the base film. The use of the base film is preferable because the charging of the surface protective film itself when peeled is suppressed. In addition, the base film is a plastic film, and the antistatic treatment is applied to the plastic film to reduce the charge of the surface protection film itself and to reduce the antistatic ability of the adherend (reflection type polarizing film). Excellent things are obtained. The method of imparting the antistatic function is not particularly limited, and a conventionally known method can be used. For example, an antistatic resin or a conductive polymer including an antistatic agent and a resin component, a conductive polymer, or a conductive substance may be used. Examples of the method include a method of applying a conductive resin to be contained, a method of depositing or plating a conductive substance, a method of kneading an antistatic agent and the like, and a method of forming an antistatic layer.

  The thickness of the base film is usually about 5 to 200 μm, preferably about 10 to 100 μm. When the thickness of the base film is within the above range, the workability of laminating on the adherend (reflection type polarizing film) and the workability of peeling off from the adherend are preferable.

  The surface protective film disclosed herein can be implemented in an embodiment including an antistatic layer and another layer in addition to the base film and the pressure-sensitive adhesive layer. Examples of the other layer include an undercoat layer (anchor layer) for improving the anchoring property of the antistatic layer and the pressure-sensitive adhesive layer.

<Adhesive composition>
The pressure-sensitive adhesive composition for a reflective polarizing film of the present invention is in a liquid state at room temperature (25 ° C.) and contains an ionic compound having a viscosity (25 ° C.) of 550 mPa · s or less, and a pressure-sensitive adhesive polymer. It is characterized by the following. By using the ionic compound, compared to an optical film such as a polarizing film, after being applied to a reflective polarizing film formed of a multilayer structure that is easily charged, even after peeling, peeling antistatic properties. And a preferred embodiment.

  The pressure-sensitive adhesive composition of the present invention can be used without any particular limitation as long as it contains a pressure-sensitive adhesive polymer, and a pressure-sensitive adhesive layer can be formed from the pressure-sensitive adhesive composition. As the pressure-sensitive adhesive composition, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a synthetic rubber-based pressure-sensitive adhesive, a natural rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and the like, among which more preferably, The adhesive polymer is at least one selected from the group consisting of a (meth) acryl-based polymer, a urethane-based polymer, and a silicone-based polymer, and an acrylic-based pressure-sensitive adhesive containing a (meth) acryl-based polymer, urethane Urethane-based pressure-sensitive adhesive containing a silicone-based polymer, and those using (contained) at least one selected from the group consisting of silicone-based pressure-sensitive adhesives containing a silicone-based polymer, more preferably, That is, an acrylic pressure-sensitive adhesive using a (meth) acrylic polymer that is a polymer is used.

  When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, the (meth) acryl-based polymer, which is a pressure-sensitive adhesive polymer that forms the acrylic pressure-sensitive adhesive, is used as a raw material monomer for forming the same. A (meth) acrylic monomer having a group can be used as the main monomer. As the (meth) acrylic monomer, one or more kinds can be used. By using the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it is easy to control the peeling force (adhesive force) to an adherend (reflection type polarizing film) to be low, and light A surface protective film having excellent releasability (removability) can be obtained.

  In the present invention, the (meth) acrylic polymer refers to an acrylic polymer and / or a methacrylic polymer, and the (meth) acrylate refers to an acrylate and / or a methacrylate. Further, as the (meth) acrylic monomer, one or more kinds can be used as a main component.

  Specific examples of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and s-butyl (meth). ) Acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl ( (Meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, and the like. Can be

  In particular, the surface protective film includes n-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, and n-nonyl. (Meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. (Meth) acrylic monomers having an alkyl group having 4 to 14 carbon atoms are preferred. In particular, by using a (meth) acrylic monomer having an alkyl group having 4 to 14 carbon atoms, the peeling force (adhesive force) to the adherend (reflective polarizing film) can be easily controlled to be low, and Excellent peelability (removability).

  In particular, it is preferable to contain 70% by weight or more of a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, based on 100% by weight of the total amount of the monomer components constituting the (meth) acrylic polymer. , More preferably 80% by weight or more, further preferably 85 to 99% by weight, particularly preferably 88 to 98% by weight. If the content is less than 70% by weight, the wettability of the pressure-sensitive adhesive composition and the cohesive strength of the pressure-sensitive adhesive layer become poor, which is not preferable.

  Further, it is preferable that the (meth) acrylic polymer contains a hydroxyl group-containing (meth) acrylic monomer as a monomer component. As the hydroxyl group-containing (meth) acrylic monomer, one kind or two or more kinds can be used. The use of the hydroxyl group-containing (meth) acrylic monomer makes it easier to control crosslinking of the pressure-sensitive adhesive composition, and thus balances the improvement of wettability by flow and the reduction of peeling force (adhesive force) in peeling. Easy to control.

  Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate , 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, and the like. . In particular, the use of a hydroxyl group-containing (meth) acrylic monomer having an alkyl group having 4 or more carbon atoms is preferable because light release at the time of high-speed release is facilitated.

  The hydroxyl group-containing (meth) acrylic monomer preferably contains 20% by weight or less, more preferably 18% by weight or less, based on 100% by weight of the total amount of the monomer components constituting the (meth) acrylic polymer. , More preferably 0.1 to 16% by weight, particularly preferably 1 to 14% by weight. It is preferable for it to be in the above-mentioned range because the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the obtained pressure-sensitive adhesive layer can be easily controlled.

  Further, as another polymerizable monomer component, the Tg is set to 0 ° C. or lower (usually −100 ° C. or higher) so that the glass transition temperature and the peeling of the (meth) acrylic polymer can be improved because the adhesion performance can be easily balanced. A polymerizable monomer or the like for adjusting the properties can be used as long as the effects of the present invention are not impaired.

  As the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer, and other polymerizable monomers other than the hydroxyl group-containing (meth) acrylic monomer, A carboxyl group-containing (meth) acrylic monomer can be used. By using the carboxyl group-containing (meth) acrylic monomer, an increase in the adhesive force of the surface protective film (adhesive layer) over time can be suppressed, and the light peelability (removability) and the increase in the adhesive force can be suppressed. It is excellent in prevention property and workability, and also excellent in shear force as well as cohesive force of the pressure-sensitive adhesive layer, which is preferable.

  Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, and carboxyl pentyl (meth) acrylate.

  The carboxyl group-containing (meth) acrylic monomer is preferably 0 to 3% by weight, preferably 0.001 to 2% by weight, based on 100% by weight of the total amount of the monomer components constituting the (meth) acrylic polymer. Is more preferable, 0.005 to 1% by weight is more preferable, and 0.001 to 0.5% by weight is particularly preferable. It is preferable for it to be in the above-mentioned range because the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the obtained pressure-sensitive adhesive layer can be easily controlled.

  Further, other polymerizable monomers can be used without any particular limitation as long as the properties of the present invention are not impaired. For example, components for improving cohesion and heat resistance such as cyano group-containing monomers, vinyl ester monomers, and aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and N-acryloyl morpholine In addition, a component having a functional group that functions as a base for improving a peeling force (adhesive force) or a crosslinking point, such as a vinyl ether monomer, can be used as appropriate. Among them, it is preferable to use a cyano group-containing monomer, an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, and a nitrogen-containing monomer such as N-acryloylmorpholine. One or more of these polymerizable monomers can be used.

  Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethyl Examples include methacrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, diacetoneacrylamide and the like.

  Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

  Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl (meth) acrylate.

  Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, and vinyl laurate.

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrenes.

  Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

  Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether.

  The other polymerizable monomer is preferably 0 to 30% by weight, more preferably 0 to 20% by weight, based on 100% by weight of the total amount of the monomer components constituting the (meth) acrylic polymer. . The other polymerizable monomers can be appropriately adjusted to obtain desired properties.

  Further, the (meth) acrylic polymer may further contain an alkylene oxide group-containing reactive monomer as a monomer component.

  The (meth) acrylic polymer preferably has a weight average molecular weight (Mw) of 100,000 to 2,000,000, more preferably 200,000 to 1,000,000, further preferably 300,000 to 800,000, particularly preferably 300,000 to 700,000. It is. When the weight average molecular weight is smaller than 100,000, adhesive force tends to remain due to a decrease in the cohesive force of the pressure-sensitive adhesive layer. On the other hand, when the weight average molecular weight is more than 2,000,000, the fluidity of the polymer decreases, the wetting on the adherend (reflection type polarizing film) becomes insufficient, and the adherend and the pressure-sensitive adhesive layer of the surface protective film become It tends to cause blistering that occurs during The weight average molecular weight refers to a value obtained by measurement by GPC (gel permeation chromatography).

  Further, the glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C or lower, more preferably -20 ° C or lower, further preferably -40 ° C or lower, and particularly preferably -50 ° C. Or less (usually -100 ° C or higher). When the glass transition temperature is higher than 0 ° C., the polymer is less likely to flow and, for example, the wetting on the adherend (reflection type polarizing film) becomes insufficient, and between the adherend and the pressure-sensitive adhesive layer of the surface protective film. It tends to cause blistering. In particular, by setting the glass transition temperature to −60 ° C. or lower, it becomes easy to obtain an adhesive layer excellent in wettability to an adherend and light releasability (removability). The glass transition temperature of the (meth) acrylic polymer can be adjusted within the above range by appropriately changing the monomer components and the composition ratio used.

  The method for polymerizing the (meth) acrylic polymer is not particularly limited, and can be polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization. Solution polymerization is a more preferred embodiment from the viewpoint of characteristics such as low contamination to the adherend (reflection type polarizing film). Further, the obtained polymer may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer and the like.

When a urethane-based pressure-sensitive adhesive is used for the pressure-sensitive adhesive layer, any appropriate urethane-based pressure-sensitive adhesive can be adopted. As such a urethane-based pressure-sensitive adhesive, preferably, a urethane-based pressure-sensitive adhesive obtained by reacting a polyol with a polyisocyanate compound is used. Examples of the polyol include a polyether polyol, a polyester polyol, a polycarbonate polyol, and a polycaprolactone polyol. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate.

  When a silicone-based pressure-sensitive adhesive is used for the pressure-sensitive adhesive layer, any appropriate silicone-based pressure-sensitive adhesive can be employed. As such a silicone-based pressure-sensitive adhesive, one obtained by blending or aggregating a silicone-based polymer, which is a pressure-sensitive adhesive polymer, can be preferably used.

  Examples of the silicone adhesive include an addition reaction-curable silicone adhesive and a peroxide-curable silicone adhesive. Among these silicone-based pressure-sensitive adhesives, addition reaction-curable silicone-based pressure-sensitive adhesives are preferable because they do not use peroxides (such as benzoyl peroxide) and do not generate decomposition products.

  As a curing reaction of the addition reaction-curable silicone-based pressure-sensitive adhesive, for example, when a polyalkylsilicone-based pressure-sensitive adhesive is obtained, a method of curing a polyalkylhydrogensiloxane composition with a platinum catalyst is generally used.

<Ionic compound>
The pressure-sensitive adhesive composition is characterized by being in a liquid state at room temperature (25 ° C.) and containing an ionic compound having a viscosity (25 ° C.) of 550 mPa · s or less. The ionic compound is a so-called ionic liquid, and refers to a molten salt that exhibits a liquid state at room temperature (25 ° C.). By containing the ionic compound, excellent antistatic properties and peeling antistatic properties can be imparted. Although the reason why the excellent antistatic property is obtained by using the ionic compound is not clear, it is liquid at room temperature (25 ° C.), and therefore, compared to a solid antistatic agent at room temperature, the adhesive is It is considered that the compound can be easily added to (adhesive composition) and dispersed or dissolved, and excellent antistatic ability can be obtained. In particular, when antistatic is applied to an adherend (reflection type polarizing film), a very small amount of an ionic compound is transferred to the adherend, so that excellent exfoliation antistatic property on the adherend is achieved. it is conceivable that.

  The ionic compound has a viscosity at 25 ° C. (room temperature) of 550 mPa · s or less, preferably 500 mPa · s or less, more preferably 450 mPa · s or less, and still more preferably 10 to 50 mPa · s or less. 400 mPa · s, particularly preferably 15 to 250 mPa · s. If the viscosity of the ionic compound at 25 ° C. is within the above range, the electric conductivity (conductivity) of the ionic compound tends to be high, and the generated peeling voltage can be quickly released, The fluidity of the ionic compound is high, the dispersion in the pressure-sensitive adhesive layer is also good, and the ionic compound easily moves to the surface of the pressure-sensitive adhesive layer which comes into contact with the adherend (reflection type polarizing film), so that high-dimensional It is possible to prevent peeling charging, which is a preferable embodiment. The measurement of the viscosity in the present invention is a value measured at 25 ° C. using a viscometer (RE-85U, manufactured by Toki Sangyo Co., Ltd.) The cone rotor uses 1 ° 34 ′ × R24, and the rotation speed is It was measured as 12 rpm.

  The electric conductivity (25 ° C.) of the ionic compound is preferably 0 to 20 mS / cm, more preferably 0.01 to 18 mS / cm, and still more preferably 0.1 to 16 mS / cm. It is. When the electrical conductivity (conductivity) at 25 ° C. of the ionic compound is within the above range, it is possible to quickly release the generated peeling electrostatic voltage, and to easily adhere to the adherend (reflection type polarizing film) having a multilayer structure. ), Excellent peeling antistatic properties can be exhibited, which is a preferred embodiment.

The ionic compound may be in a liquid state at room temperature (25 ° C.) and have a viscosity (25 ° C.) of 550 mPa · s or less. For example, a compound comprising a cation component (organic cation component) and an anion component It is preferably used, and particularly, from the viewpoints of low viscosity and high electric conductivity (conductivity), the following ionic compounds are preferably used.
For example, as the ionic compound, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide, 1-ethyl-3-methylimidazolium bis (trifluoromethane Sulfonyl) imide, 1-methyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium bis (trifluoro) 1-decyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-dodecylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl 2,3-dimethylimidazolium bis (trifluoromethanesulfonyl) imide, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-2-dimethylimidazolium bis (trifluoromethanesulfonyl) ) Imide, 1-ethyl-3-vinylimidazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-vinylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (trifluoro) 1-butyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-butyl-1-methylpiperidinium bis (trifluoromethanesulfonyl) imide, 4- (2- (Toxiethyl) -4-methylmorpholinium bis (trifluoromethanesulfonyl) imide, 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) ) Imide, 1-butyl-4-methylpyridinium tetrafluoroborate, 1-butyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-hexyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-octyl -4-methylpyridinium bis (trifluoromethanesulfonyl) imide, tributyldodecylphosphonium bis (trifluoromethanesulfonyl) imide, trimethyl Pyrammonium bis (trifluoromethanesulfonyl) imide, butyltrimethylammonium bis (trifluoromethanesulfonyl) imide, triethylsulfonium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium trifluoromethanesulfonic acid, and the like, Among them, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, triethyl Sulfonium bis (trifluoromethanesulfonyl) imide and 1-butyl-3-methylpyridinium trifluoromethanesulfonate have low viscosity and electric Preferably used in view of Shirubedo (conductivity).

  These ionic compounds may be used alone or as a mixture of two or more.

  The content of the ionic compound is, for example, preferably 0.01 to 5 parts by weight, more preferably 0.02 to 4 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer constituting the pressure-sensitive adhesive composition. Parts by weight, more preferably 0.05 to 3 parts by weight, particularly preferably 0.1 to 2 parts by weight. When the content is within the above range, the surface protective film of the present invention is preferable because the antistatic property and the low contamination property are easily compatible with the adherend (the reflective polarizing film).

<Silicone component>
It is preferable that the viscous surface protective film for a reflective polarizing film of the present invention contains a silicone component. By using the silicone component, the surface free energy of the surface of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is reduced, lightening at the time of peeling can be realized, and the surface of the pressure-sensitive adhesive layer of the ionic compound can be reduced. Is promoted, so that the peeling voltage can be suppressed, which is a preferable embodiment.

<Organopolysiloxane having oxyalkylene chain>
As the silicone component, for example, an organopolysiloxane having an oxyalkylene chain can be used. As the organopolysiloxane, a known organopolysiloxane having a polyoxyalkylene main chain can be appropriately used, but is preferably represented by the following formula.
(Wherein, R ₁ and / or R ₂ have an oxyalkylene chain having 1 to 6 carbon atoms, and the alkylene group in the oxyalkylene chain may be linear or branched; May be an alkoxy group or a hydroxyl group, and _one of R _{1 and} R ₂ may be a hydroxyl group, or may be an alkyl group or an alkoxy group; (A part of the group and the alkoxy group may be a functional group substituted with a hetero atom. N is an integer of 1 to 300.)

  As the organopolysiloxane, one having a siloxane-containing site (siloxane site) as a main chain and an oxyalkylene chain bonded to the terminal of the main chain is used. It is presumed that the use of the organosiloxane having an oxyalkylene chain balances the compatibility with the adhesive polymer and the ionic compound, and realizes light exfoliation.

Further, as the organopolysiloxane in the present invention, for example, the following configuration can be used. Specifically, R ₁ and / or R ₂ in the formula has an oxyalkylene chain containing a hydrocarbon group having 1 to 6 carbon atoms, and the oxyalkylene chain includes an oxymethylene group, an oxyethylene group, and an oxyalkylene chain. Examples thereof include a propylene group and an oxybutylene group, and among them, an oxyethylene group and an oxypropylene group are preferable. When R ₁ and R ₂ both have an oxyalkylene chain, they may be the same or different.

  Further, the hydrocarbon group of the oxyalkylene chain may be linear or branched.

  Further, the terminal of the oxyalkylene chain may be an alkoxy group or a hydroxyl group, and among them, an alkoxy group is more preferable. When a separator is bonded to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface, the organopolysiloxane having a hydroxyl group at the end thereof interacts with the separator and causes adhesion (peeling) when the separator is peeled off from the surface of the pressure-sensitive adhesive layer. Power may rise.

  N is an integer of 1 to 300, preferably 10 to 200, and more preferably 20 to 150. When n is within the above range, the compatibility with the base polymer is balanced, which is a preferable embodiment. Further, the molecule may have a reactive substituent such as a (meth) acryloyl group, an allyl group, and a hydroxyl group. The organopolysiloxanes may be used alone or in combination of two or more.

  Specific examples of the organopolysiloxane having an oxyalkylene chain include, for example, commercially available products having trade names of X-22-4952, X-22-4272, X-22-6266, KF-6004, and KF-889. (Manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (manufactured by Dow Corning Toray), IM22 (manufactured by Asahi Kasei Wacker Inc.), and the like. These compounds may be used alone or as a mixture of two or more.

Further, as the silicone component, in addition to the organosiloxane having an oxyalkylene chain in the main chain (bonding), it is also possible to use an organosiloxane having an oxyalkylene chain in the side chain (bonding). It is a more preferred embodiment to use an organosiloxane having an oxyalkylene chain in the side chain. As the organopolysiloxane, a known organopolysiloxane having a polyoxyalkylene side chain can be appropriately used, and is preferably represented by the following formula.
(Wherein, R ₁ is a monovalent organic group, R ₂ , R ₃ and R ₄ are alkylene groups, R ₅ is hydrogen or an organic group, m and n are integers of 0 to 1000, provided that m and n are the same. A and b are integers of 0 to 100, provided that a and b are not 0 at the same time.)

Further, as the organopolysiloxane in the present invention, for example, the following configuration can be used. Specifically, R ₁ in the formula is a monovalent group exemplified by an alkyl group such as a methyl group, an ethyl group and a propyl group, an aryl group such as a phenyl group and a tolyl group, or an aralkyl group such as a benzyl group and a phenethyl group. It is an organic group and each may have a substituent such as a hydroxyl group. As R ₂ , R ₃ and R _4, an alkylene group having 1 to 8 carbon atoms such as a methylene group, an ethylene group and a propylene group can be used. Here, R ₃ and R ₄ are different alkylene groups, and R ₂ may be the same as or different from R ₃ or R ₄ . One of R ₃ and R ₄ is preferably an ethylene group or a propylene group in order to increase the concentration of the ionic compound that can be dissolved in the polyoxyalkylene side chain. R ₅ may be a monovalent organic group exemplified by an alkyl group such as a methyl group, an ethyl group and a propyl group or an acyl group such as an acetyl group and a propionyl group, each having a substituent such as a hydroxyl group. May be. These compounds may be used alone or as a mixture of two or more. In addition, the molecule may have a reactive substituent such as a (meth) acryloyl group, an allyl group, a hydroxyl group, or the like. Among the above-mentioned organosiloxanes having a polyoxyalkylene side chain, an organosiloxane having a polyoxyalkylene side chain having a hydroxyl group terminal is preferable because it is presumed that the compatibility is easily balanced.

  Specific examples of the above-mentioned organosiloxane include, for example, trade names KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, and KF as commercial products. -642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (Shin-Etsu Chemical Co., Ltd.) SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ-7001, SH8400, SH8700 , SF8410, SF8422 (all manufactured by Dow Corning Toray), TSF-44 0, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460 (manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (manufactured by BYK Japan KK) and the like. These compounds may be used alone or in combination of two or more.

  The organosiloxane used in the present invention has an HLB (Hydrophile-Lipophile Balance) value of preferably from 1 to 16, more preferably from 3 to 14. If the HLB value is out of the above range, the contamination on the adherend (reflection type polarizing film) is deteriorated, which is not preferable.

<Ionic group-containing silicone>
In addition, an ionic group-containing silicone can be used as the silicone component. By using the ionic group-containing silicone, the silicone component having a low surface energy and the ionic compound are integrated, so that the transfer of the ionic compound to the surface of the pressure-sensitive adhesive layer is facilitated. Become.

As the ionic group-containing silicone, it is preferable to use an ionic group-containing silicone represented by the following formula (1). When the pressure-sensitive adhesive composition contains the ionic group-containing silicone, the pressure-sensitive adhesive layer is stuck to the surface of the adherend (reflection type polarizing film) due to the low surface free energy of the silicone chain. Even if stored, the ionic group-containing silicone does not penetrate into the adherend (from the surface of the adherend to the inside of the adherend) and tends to remain on the surface of the pressure-sensitive adhesive layer. This is a preferred embodiment in which the peeling charging characteristics are stable and the antistatic performance is maintained for a long period of time. The `` inside '' of the pressure-sensitive adhesive layer is, for example, when the pressure-sensitive adhesive layer is formed using the pressure-sensitive adhesive composition containing the ionic group-containing silicone, and is included in the pressure-sensitive adhesive layer. Point to. Further, the “surface” of the pressure-sensitive adhesive layer refers to, for example, when the pressure-sensitive adhesive layer is formed by using the pressure-sensitive adhesive composition containing the ionic group-containing silicone or not mixed, In order to protect the surface of the agent layer, the ionic group-containing silicone is applied (laminated) in advance on the surface of the separator to be attached, and when the adhesive layer is attached to the separator, It refers to the case where the ionic group-containing silicone is transferred (transferred) to the surface of the pressure-sensitive adhesive layer.
In the above formula (1), R _{1 to} R ₄ may be the same or different, and may have an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an aryl group, an alicyclic group, a fluorine-substituted alkyl group, an ion And at least _one of R _{1 to} R ₄ contains an ionic group. n is an integer of 0 to 100.

Further, as the ionic group contained in one or more of R _{1 to} R ₄ , an ionic group having an ammonium cation group or a phosphonium cation group is preferable. Among them, at least one of R _{1 to} R ₄ preferably comprises a cation structure represented by the following formula (a) or (b) and an anion component, or is represented by (c) or (d). Preferably, the zwitterion structure is

R _{5 to} R ₇ in the above formula (a) may be the same or different and represent any one of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group. m is an integer of 1 to 10.

R _{8 to} R ₁₀ in the above formula (b) may be the same or different and represent any of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group. m is an integer of 1 to 10.

On the other hand, the anion component is not particularly limited, and for example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH _{3 3} COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (C ₃ F ₇ SO ₂ ) ₂ N ⁻ , (C ₄ F ₉ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ^{− _{, F (HF) n -,}} (CN) 2 n -, C 4 F 9 SO 3 -, (C 2 F 5 SO 2) 2 n -, C 3 F 7 COO -, (CF 3 SO 2) (CF _{^{3 CO) N -, C 9}} H 19 COO -, (CH 3) _{^{PO 4 -, (C 2 H}} 5) 2 PO 4 -, C 2 H 5 OSO 3 -, C 6 H 13 OSO 3 -, C 8 H 17 OSO 3 -, CH 3 (OC 2 H 4) 2 OSO 3 _{^{-, C 6 H 4 (CH}} 3) SO 3 -, (C 2 F 5) 3 PF 3 -, CH 3 CH (OH) COO -, _{and, (FSO 2) 2} N ^- and the like are used.

R ₁₁ and R ₁₂ in the above formula (c) may be the same or different and represent any of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group, and R ₁₁ and R ₁₂ are It may form a ring, in which case it represents an alkylene group. m is an integer of 1 to 10, and p is an integer of 1 to 6.

R ₁₃ and R ₁₄ in the above formula (d) may be the same or different and represent any of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group, and R ₁₃ and R ₁₄ represent It may form a ring, in which case it represents an alkylene group. m is an integer of 1 to 10, and p is an integer of 1 to 6.

  Since such an ionic group-containing silicone contains a silicone chain, it is stored in a high-temperature environment with the pressure-sensitive adhesive layer adhered to the surface of the adherend (reflective polarizing film) due to the low surface free energy of the silicone chain. Even in this case, the ionic group-containing silicone does not penetrate into the adherend (from the surface of the adherend to the inside of the adherend) and tends to remain on the surface of the pressure-sensitive adhesive layer. The properties are stable, the antistatic performance is maintained for a long time, and it can be suitably used as an antistatic agent.

  Examples of the ionic group-containing silicone include, for example, commercially available products such as X-40-2450 and X-40-2750 (all manufactured by Shin-Etsu Chemical Co., Ltd.). These compounds may be used alone or in combination of two or more.

  Further, for example, the content of the silicone component is preferably 0.01 to 5 parts by weight, more preferably 0.03 to 3 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer which is an adhesive polymer. Parts, more preferably 0.05 to 1 part by weight. It is preferable that the content is in the above-mentioned range, since it is easy to achieve both the antistatic property for peeling and the light peeling property (removability).

<Fluorine oligomer>
The pressure-sensitive adhesive composition may contain a fluorine-based oligomer. By containing the fluorine-based oligomer in the pressure-sensitive adhesive composition, when the obtained pressure-sensitive adhesive layer (surface protective film) is adhered to an adherend (reflection-type polarizing film), the fluorine site in the fluorine-based oligomer is Light peeling effect due to low surface free energy can be exhibited.

  The fluorine-based oligomer preferably has a hydroxyl value of 1 or more, more preferably 5 or more, further preferably 10 or more, particularly preferably 20 or more, and most preferably 40 or more. When the hydroxyl value of the fluorinated oligomer is 1 or more, the interaction between the fluorinated oligomer and the adhesive polymer is strengthened, the transfer amount to the adherend (reflection type polarizing film) is reduced, and the Slippage (shift), floating and peeling can be suppressed. Furthermore, it is preferable that the hydroxyl value is 20 or more, because the stain resistance (low stain resistance) is more excellent. Further, the hydroxyl value of the fluorine-based oligomer is preferably 500 or less, more preferably 400 or less. When the hydroxyl value of the fluorine-based oligomer exceeds 500, the reaction between the fluorine-based oligomer and the cross-linking agent is prioritized, which hinders the reaction between the original cross-linking agent and the adhesive polymer, and the cohesive force may be reduced. This is not preferred.

  Specific examples of the fluorine-based oligomer include, for example, commercially available trade names of Megafac F-577, F-556, F-559, F-562, F-563, F-569, F-571 (or more) And DIC). These compounds may be used alone or as a mixture of two or more.

  The content of the fluorine-based oligomer is based on 100 parts by weight of an adhesive polymer (a base polymer, for example, a (meth) acryl-based polymer, a urethane-based polymer, a silicone-based polymer, etc.) constituting the pressure-sensitive adhesive composition. , 0.01 to 5 parts by weight, more preferably 0.02 to 4 parts by weight, still more preferably 0.04 to 3 parts by weight, and most preferably 0.06 to 2 parts by weight. When it is within the above range, after the surface protective film used in the present invention is bonded to an adherend (reflection type polarizing film), slippage (deviation), floating and peeling can be suppressed, and further, a light peeling effect is obtained. Excellent and preferred. In order to satisfy the appearance as a surface protective film, the content of the fluorine-based oligomer is preferably 0.01 to 1.5 parts by weight based on 100 parts by weight of the adhesive polymer.

<Crosslinking agent>
In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains a crosslinking agent. In the present invention, the pressure-sensitive adhesive layer can be formed by using the pressure-sensitive adhesive composition. For example, when the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive containing the (meth) acrylic polymer, the constitutional unit, the composition ratio of the (meth) acrylic polymer, the selection and the addition ratio of the crosslinking agent, and the like are appropriately determined. By controlling and crosslinking, a surface protective film (adhesive layer) having more excellent heat resistance can be obtained.

  As the crosslinking agent used in the present invention, an isocyanate compound, an epoxy compound, a melamine-based resin, an aziridine derivative, a metal chelate compound, or the like may be used. In particular, the use of an isocyanate compound is a preferred embodiment. Further, these compounds may be used alone or in combination of two or more.

  Examples of the isocyanate compound include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI) and dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate (IPDI), Alicyclic isocyanates such as 3-bis (isocyanatomethyl) cyclohexane, aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate (XDI), and the isocyanate compound Allophanate bond, biuret bond, isocyanurate bond, uretdione bond, urea bond, carbodiimide bond, A modified polyisocyanate modified by a retonimine bond, an oxadiazinetrione bond, or the like can be given. For example, as commercial products, trade names Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (manufactured by Mitsui Chemicals, Inc.), Sumidur T80, Sumidur L, Desmodur N3400 (above, Sumika Bayer Urethane Co., Ltd.) ), Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (all manufactured by Tosoh Corporation) and the like. These isocyanate compounds may be used alone or in combination of two or more, and it is also possible to use a bifunctional isocyanate compound and a trifunctional or more functional isocyanate compound in combination. By using a cross-linking agent in combination, it is possible to achieve both adhesiveness and repulsion resistance (adhesion to a curved surface), and a surface protective film having more excellent adhesive properties can be obtained.

  Examples of the epoxy compound include N, N, N ', N'-tetraglycidyl-m-xylenediamine (trade name: TETRAD-X, manufactured by Mitsubishi Gas Chemical Company) and 1,3-bis (N, N-diene). Glycidylaminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company) and the like.

  Examples of the melamine-based resin include hexamethylolmelamine. Examples of the aziridine derivative include HDU, TAZM, TAZO (trade names, manufactured by Mutual Pharmaceutical Co., Ltd.) as commercial products.

  Examples of the metal chelate compound include aluminum, iron, tin, titanium, nickel and the like as metal components, and acetylene, methyl acetoacetate, ethyl lactate and the like as chelate components.

  The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 20 parts by weight, and more preferably 0.1 to 15 parts by weight based on 100 parts by weight of the (meth) acrylic polymer. More preferably, it is more preferably 0.5 to 10 parts by weight, and particularly preferably 1 to 5 parts by weight. When the content is less than 0.01 part by weight, crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the obtained pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained. It tends to cause glue residue. On the other hand, if the content exceeds 20 parts by weight, the cohesive strength of the polymer is large, the fluidity is reduced, and the wetting on the adherend (reflective polarizing film) becomes insufficient, and the adherend and the adhesive It tends to cause blisters generated between the layer and the pressure-sensitive adhesive composition layer.

  The pressure-sensitive adhesive composition may further contain a crosslinking catalyst for causing any of the above-described crosslinking reactions to proceed more effectively. Examples of such a crosslinking catalyst include tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonato) iron, tris (hexane-2,4-dionato) iron, and tris (heptane-2,4-dionato). ) Iron, tris (heptane-3,5-dionato) iron, tris (5-methylhexane-2,4-dionato) iron, tris (octane-2,4-dionato) iron, tris (6-methylheptane-2) , 4-dionato) iron, tris (2,6-dimethylheptane-3,5-dionato) iron, tris (nonane-2,4-dionato) iron, tris (nonane-4,6-dionato) iron, tris ( 2,2,6,6-tetramethylheptane-3,5-dionato) iron, tris (tridecane-6,8-dionato) iron, tris (1-phenylbutane-1,3) -Dionato) iron, tris (hexafluoroacetylacetonato) iron, tris (ethyl acetoacetate) iron, tris (acetoacetate-n-propyl) iron, tris (isopropylacetoacetate) iron, tris (acetoacetate-n-butyl) ) Iron, tris (acetoacetate-sec-butyl) iron, tris (acetoacetate-tert-butyl) iron, tris (methyl propionyl acetate) iron, tris (ethyl propionyl acetate) iron, tris (propionyl acetate-n-propyl) Iron, tris (propionyl acetate-isopropyl) iron, tris (propionyl acetate-n-butyl) iron, tris (propionyl acetate-sec-butyl) iron, tris (propionyl acetate-tert-butyl) iron, tris (benzyl acetoacetate) iron , Tris (dimethyl malonate) iron, tris (diethyl malonate) iron, trimethoxyiron Triethoxy iron, triisopropoxy iron, can be used an iron-based catalyst such as ferric chloride. One of these crosslinking catalysts may be used alone, or two or more thereof may be used in combination.

  The content of the crosslinking catalyst is not particularly limited. For example, the content is preferably about 0.0001 to 1 part by weight, and more preferably 0.001 to 0.5 part by weight based on 100 parts by weight of the (meth) acrylic polymer. Parts by weight are more preferred. When it is within the above range, the speed of the crosslinking reaction when the pressure-sensitive adhesive layer is formed is high, which is a preferable embodiment.

  Further, the pressure-sensitive adhesive composition may contain a compound that causes keto-enol tautomerism. For example, in a pressure-sensitive adhesive composition containing a cross-linking agent or a pressure-sensitive adhesive composition that can be used by blending a cross-linking agent, an embodiment containing the compound that produces the keto-enol tautomerism can be preferably employed. Thereby, an effect of suppressing an excessive increase in viscosity and gelation of the pressure-sensitive adhesive composition after blending the cross-linking agent and extending the pot life of the pressure-sensitive adhesive composition can be realized. When at least an isocyanate compound is used as the cross-linking agent, it is particularly significant to include a compound that causes keto-enol tautomerism. This technique can be preferably applied, for example, when the pressure-sensitive adhesive composition is in an organic solvent solution or solventless form.

  As the compound causing keto-enol tautomerism, various β-dicarbonyl compounds can be used. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, and 2,6-dimethylheptane- Β-diketones such as 3,5-dione; acetoacetates such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate and tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, and propionyl acetate propionyl acetates such as tert-butyl; ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, isobutyryl acetates such as tert-butyl isobutyryl acetate; malonic esters such as methyl malonate and ethyl malonate; And the like. Among them, preferred compounds include acetylacetone and acetoacetates. The compounds which cause such keto-enol tautomerism may be used alone or in combination of two or more.

  The content of the compound capable of producing the keto-enol tautomerism may be, for example, 0.1 to 20 parts by weight, and usually 0.5 to 20 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer. It is appropriate to use 15 parts by weight (for example, 1 to 10 parts by weight). If the amount of the compound is too small, it may be difficult to exert a sufficient use effect. On the other hand, if the compound is used more than necessary, it may remain in the pressure-sensitive adhesive layer and reduce cohesion.

  Further, the pressure-sensitive adhesive composition may contain other known additives, for example, powders such as lubricants, colorants, pigments, plasticizers, tackifiers, low molecular weight polymers, surface lubrication Use agents, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils, etc. It can be appropriately added depending on the intended use.

<Adhesive layer and surface protection film>
The surface protective film of the present invention preferably has an adhesive layer formed of the adhesive composition on at least one surface of the base film. The pressure-sensitive adhesive layer is obtained by crosslinking the pressure-sensitive adhesive composition, and is generally performed after the application of the pressure-sensitive adhesive composition. It is also possible to transfer it to a film or the like.

  The method for forming the pressure-sensitive adhesive layer on the substrate film is not particularly limited. For example, the pressure-sensitive adhesive composition (solution) is applied to a substrate film, and the polymerization solvent and the like are dried and removed to form the pressure-sensitive adhesive layer. It is produced by forming on a base film. Thereafter, curing may be performed for the purpose of adjusting the migration of components of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. Further, when preparing a surface protective film by applying the pressure-sensitive adhesive composition on the substrate film, so that it can be uniformly applied on the substrate film, one or more kinds of polymerization solvent other than the polymerization solvent in the pressure-sensitive adhesive composition. A new solvent may be added.

  In addition, as a method for forming the pressure-sensitive adhesive layer when the surface protective film of the present invention is produced, a known method used for producing pressure-sensitive adhesive tapes is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and extrusion coating using a die coater.

  The surface protective film of the present invention is usually prepared so that the pressure-sensitive adhesive layer has a thickness of 0.1 to 100 μm, preferably about 1 to 80 μm. It is preferable that the thickness of the pressure-sensitive adhesive layer be in the above-mentioned range because a proper balance between removability and adhesiveness can be easily obtained.

  Further, the total thickness of the surface protective film of the present invention is preferably from 8 to 300 µm, more preferably from 10 to 200 µm, most preferably from 20 to 100 µm. When the content is within the above range, the adhesive properties (removability, adhesiveness, etc.), workability, and appearance properties are excellent, which is a preferable embodiment. In addition, the said total thickness means the total of the thickness containing all the layers, such as a base film, an adhesive layer, and other layers.

<Separator>
It is preferable that a separator is attached to the surface protective film of the present invention on a surface of the pressure-sensitive adhesive layer opposite to a surface in contact with the base film. The separator, for the purpose of protecting the adhesive surface if necessary, it is possible to paste a separator on the surface of the pressure-sensitive adhesive layer, when pasting on the reflective polarizing film surface, peel off the separator and use be able to.

  Examples of the material constituting the separator include paper and a plastic film, and a plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it can protect 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, and a vinyl chloride copolymer. Examples include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the separator is usually about 5 to 200 μm, preferably about 10 to 100 μm. It is preferable for it to be in the above-mentioned range because the workability of laminating to the pressure-sensitive adhesive layer and the workability of peeling from the pressure-sensitive adhesive layer are excellent. The separator, if necessary, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder, etc., coating type, kneading type, evaporation type For example, an antistatic treatment such as the following may be performed.

<Reflective polarizing film>
A reflective polarizing film (e.g., a brightness enhancement film alone, or a laminate of a brightness enhancement film on a polarizing film, formed from a multilayer structure to which the surface protective film (the surface of the pressure-sensitive adhesive layer) is adhered and protected). And the like) are used in the form of a multilayer structure in which thin films formed of materials having different refractive index anisotropies are alternately laminated, so once charged, they are usually used. Even when an ionic compound or the like that is solid at room temperature, such as an alkali metal salt that is an antistatic agent, it is difficult to remove static electricity, and the peeling antistatic property and the antistatic property have other optical films (for example, polarization Film and the like). However, the use of the ionic compound used in the present invention is excellent in peeling antistatic property and antistatic property even for a reflective polarizing film which is easily charged, which is a preferable embodiment. In particular, when incorporating a reflective polarizing film integrated with a polarizing film that has been increasingly used in recent years into a liquid crystal display or the like (after removing the surface protective film), the whitening phenomenon of the panel can be suppressed, and workability and efficiency can be reduced. It is also excellent in property and is a preferred embodiment.

  In addition, the reflection type polarizing film in the present invention includes a brightness enhancement film having a multilayer structure alone, and a polarizing film obtained by laminating the brightness enhancement film.

  The brightness enhancement film included in the reflective polarizing film, when natural light is incident due to reflection from a backlight or a back side of a liquid crystal display device or the like, reflects linearly polarized light having a predetermined polarization axis or circularly polarized light having a predetermined direction, Other light shows the property of transmitting, further, a laminate of a brightness enhancement film and a polarizing film, while receiving light from a light source such as a backlight to obtain transmitted light of a predetermined polarization state, Light other than the predetermined polarization state is reflected without transmitting. The light reflected by the brightness enhancement film is further inverted through a reflection layer or the like provided on the rear side thereof and re-incident on the brightness enhancement film, and a part or all of the light is transmitted as light of a predetermined polarization state, thereby obtaining brightness. In addition to increasing the amount of light transmitted through the enhancement film, it is also possible to increase the amount of light that can be used for displaying an image such as a liquid crystal display by supplying polarized light that is hardly absorbed by the polarizer, thereby improving the luminance. An integrated polarizing film in which a polarizing film and a brightness enhancement film are bonded to each other is often used by being provided on the backlight side of a liquid crystal cell, but as disclosed in WO2006 / 038404, an international publication pamphlet. It can also be provided and used on the viewing side of the liquid crystal cell.

  As a brightness enhancement film, for example, a property of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of a dielectric or a multilayer laminate of thin films having different refractive index anisotropy, is used. As shown in the figure, such as a cholesteric liquid crystal polymer oriented film or a film in which the oriented liquid crystal layer is supported on a film substrate, it exhibits a property of reflecting either left-handed or right-handed circularly polarized light and transmitting other light. Any suitable one such as one can be used.

<Optical film>
The optical film of the present invention preferably has the surface protective film for a reflective polarizing film and a reflective polarizing film. The surface protective film is excellent in antistatic property for peeling when peeled off after being attached to the surface of the reflective polarizing film, so when the surface protective film is peeled off from the reflective polarizing film when it is no longer needed, an electrostatic charge is generated. The whitening phenomenon of the panel due to the above can be suppressed, and a decrease in the inspection efficiency can be suppressed, which is a preferable embodiment. In addition, the optical film in the present invention is described as a laminate of a surface protective film and a reflective polarizing film, but in addition to the reflective polarizing film, further, a laminated film such as a polarizing film and other optical films. No problem.

  Hereinafter, examples and the like specifically illustrating the configuration and effects of the present invention will be described, but the present invention is not limited to these. Evaluation items in Examples and the like were measured as follows. In the following description, “parts” and “%” are based on weight unless otherwise specified.

  Further, each characteristic in the following description was measured or evaluated as follows.

<Measurement of weight average molecular weight (Mw)>
The weight average molecular weight (Mw) of the polymer used was measured using a GPC device (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.
Sample concentration: 0.2% by weight (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
column:
Sample column: TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column: TSKgel SuperH-RC (1)
Detector: Differential refractometer (RI)
The weight average molecular weight was determined in terms of polystyrene.

<Theoretical value of glass transition temperature (Tg)>
The glass transition temperature Tg (° C.) was determined by the following equation using the following literature value as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.

Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
[Where Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the weight fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer. Represents ]
Literature values:
2-ethylhexyl acrylate (2EHA): -70 ° C
4-hydroxybutyl acrylate (4HBA): -32 ° C
Acrylic acid (AA): 106 ° C

  As the above literature values, “Synthesis and design of acrylic resin and development of new applications” (published by the Central Business Development Center Publishing Division) and “Polymer Handbook” (John Wiley & Sons) were referred to.

[Example 1]
[Preparation of (meth) acrylic polymer (A)]
91 parts by weight of 2-ethylhexyl acrylate (2EHA), 9 parts by weight of 4-hydroxybutyl acrylate (4HBA), and 0 parts of acrylic acid (AA) were placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. .02 parts by weight, 0.2 parts by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 150 parts by weight of ethyl acetate were charged, and nitrogen gas was introduced with gentle stirring, and the liquid temperature in the flask was increased. Was maintained at about 65 ° C., and a polymerization reaction was carried out for 6 hours to prepare a (meth) acrylic polymer (A) solution (40% by weight). The acrylic polymer (A) had a weight average molecular weight (Mw) of 540,000 and a glass transition temperature (Tg) of -67 ° C.

(Preparation of solution of acrylic pressure-sensitive adhesive)
The acrylic polymer (A) solution (40% by weight) was diluted to 20% by weight with ethyl acetate, and 500 parts by weight (solid content: 100 parts by weight) of this solution was added to an ionic compound (ionic liquid: 1-ethyl-3). 1 part by weight (solid content: 0.1 part by weight) of a solution obtained by diluting methyl-imidazolium bis (trifluoromethanesulfonyl) imide (manufactured by Tokyo Chemical Industry Co., Ltd.) to 10% with ethyl acetate, and a polyether-modified silicone oil as a silicone component 0.8 part by weight (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.) (solids content: 0.8 part by weight), isocyanurate of hexamethylene diisocyanate which is a trifunctional isocyanate compound (Coronate HX, manufactured by Tosoh Corporation) as a crosslinking agent 3 parts by weight (3 parts by weight of solid content), 3 parts by weight of dioctyltin dilaurate (1% by weight in ethyl acetate solution) as a crosslinking catalyst (solid content of 0%) .03 parts by weight), and mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution.

(Preparation of antistatic treatment film)
Polyester resin Vironal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) was used as a binder, and 100 parts by weight of solid content. As a conductive polymer, poly (3,4-ethylenedioxythiophene) (PEDOT) / polystyrene sulfonic acid ( PSS) (Baytron P, manufactured by H, C, Starck) in a mixed solvent of water / ethanol (1/1) in which 100 parts by weight of solid content and 10 parts by weight of hexamethylolmelamine as a cross-linking agent are used as a crosslinking agent. In addition, the mixture was stirred for about 20 minutes and mixed well. In this manner, an antistatic solution of about 0.4% NV (non-volatile content) was prepared.

  The obtained antistatic agent solution was applied on a polyethylene terephthalate (PET) film (thickness: 38 μm) as a base film using a Meyer bar, and dried at 130 ° C. for 1 minute to remove the solvent. An antistatic layer (thickness: 0.2 μm) was formed to prepare an antistatic treatment film.

[Production of surface protective film]
The acrylic pressure-sensitive adhesive solution was applied to the surface of the antistatic treatment film opposite to the surface having the antistatic layer, and heated at 130 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 10 μm. Next, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm) having one surface subjected to silicone treatment was bonded to the surface of the pressure-sensitive adhesive layer to prepare a surface protective film.

[Polarizing film with reflective polarizing film]
One side of an amorphous IPA copolymerized PET film (thickness: 100 μm) having a water absorption of 0.75% and Tg of 75 ° C. is subjected to corona treatment, and the corona treated surface is treated with polyvinyl alcohol (degree of polymerization 4200, degree of saponification). 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z200" ) Was applied at a ratio of 9: 1, and dried at 60 ° C. to form a 11 μm-thick PVA-based resin layer on the substrate, thereby producing a laminate.
The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction between rolls having different peripheral speeds in an oven at 115 ° C. (air stretching).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 30 ° C. (a boric acid aqueous solution obtained by mixing 3 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, the laminate was immersed in a dyeing solution at 30 ° C. (3.5 parts by weight of potassium iodide and 0.5 part by weight of iodine with respect to 100 parts by weight of water) for 30 seconds to be dyed (dyeing treatment).
Then, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 30 ° C. (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) (crosslinking treatment). ).
Thereafter, the laminate was immersed in a boric acid aqueous solution (aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ° C. Uniaxial stretching was performed 2.7 times in the longitudinal direction between rolls having different speeds (underwater stretching).
Thereafter, the laminate is immersed in a washing bath at a liquid temperature of 30 ° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) for 10 seconds, and then immersed in hot air at 60 ° C. for 60 seconds. It was dried for 2 seconds (washing and drying step).
In this way, a PVA-based resin layer (polarizer) having a thickness of 5 μm was formed on the resin substrate, and a polarizer laminate was obtained.

(Production Example 1: Preparation of UV-curable adhesive)
40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO) and 3 parts by weight of a photoinitiator "IRGACURE 819" (manufactured by BASF) were mixed to prepare an ultraviolet-curable adhesive.

(Production Example 2: Production of conductive pressure-sensitive adhesive layer (B))
A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with ethyl acetate to 100 parts of the above monomer mixture (solid content), and nitrogen gas was introduced with gentle stirring. After replacing with nitrogen, the polymerization reaction was carried out for 7 hours while maintaining the liquid temperature in the flask at around 60 ° C. Thereafter, ethyl acetate was added to the obtained reaction solution to adjust the solid content concentration to 30%. In this way, a solution of an acrylic polymer (base polymer) having a weight average molecular weight of 1.4 million was prepared.
For 100 parts of the solid content of the acrylic polymer solution, 1.0 part of lithium bis (trifluoromethanesulfonyl) imide (manufactured by Mitsubishi Materials Electronic Chemicals) and ethylmethylpyrrolidinium bis (trifluoromethanesulfonyl) as antistatic agents 0.7 parts of imide (manufactured by Tokyo Chemical Industry), 0.095 parts of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui Chemicals, Takenate D110N) and 0.3 part of dibenzoyl peroxide as crosslinking agents, and organo as a silane coupling agent 0.2 parts of silane (manufactured by Soken Chemical Co., Ltd .: A100), 0.2 parts of a thiol group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd .: X41-1810), rework improver (manufactured by Kaneka Corporation, Cyril SAT10) 03 parts, and an antioxidant (manufactured by BASF, Rganox1010) by blending 0.3 parts of pressure-sensitive adhesive composition (solution) was prepared.
The obtained pressure-sensitive adhesive composition is applied on a release-treated polyethylene terephthalate substrate so that the thickness of the formed pressure-sensitive adhesive layer is 20 μm, and dried by a dryer at 120 ° C. for 3 minutes. Then, a conductive pressure-sensitive adhesive layer (B) with a separator was prepared.

The ultraviolet curable adhesive of Production Example 1 was applied to the surface on the polarizer side of the polarizer laminate so that the thickness after curing became 1 μm, and a reflective polarizing film having a multilayer structure (manufactured by 3M Company, product (“APF V3”, thickness: 26 μm) was attached, and the ultraviolet-curable adhesive was cured.
Next, the PET film was peeled from the polarizer laminate, and the adhesive surface of the conductive adhesive layer with a separator (B) (thickness: 20 μm) of Production Example 2 was adhered to the peeled surface to obtain a reflective polarizing film. A polarizing film was produced.

  The polarizing film with a reflective polarizing film has a laminated structure of a conductive pressure-sensitive adhesive layer (B) (20 μm) / polarizer (5 μm) / adhesive layer (1 μm) / reflective polarizing film (26 μm). Was done.

(Polarizing film)
As a polarizing film not containing the reflective polarizing film, a product name "SEG1423DU" manufactured by Nitto Denko Corporation was used.

<Examples 2 to 11 and Comparative Examples 1 and 2>
Based on the compounding ratio in Table 1, in the same manner as in Example 1, a surface protective film, a sample for evaluation, and the like were produced. In addition, the compounding quantity in Table 1 showed the active ingredient.

<Measurement of initial peeling voltage>
The surface protective film 1 according to each example was cut into a size of 70 mm in width and 130 mm in length, and after peeling off the release liner, bonded to a glass plate, a polarizing film with a reflective polarizing film having a width of 70 mm and a length of 100 mm. 2, one end of the surface protective film is provided on the surface of the reflective polarizing film or the surface of the polarizing film 2 '(no reflective polarizing film, not shown). It was pressed by a hand roller so as to protrude 30 mm from the part (see FIG. 1).
This sample was left in an environment of 23 ° C. × 50% RH for one day, and then set at a predetermined position on a sample fixing table 3 having a height of 20 mm as shown in FIG. The end of the surface protective film 1 protruding 30 mm from the polarizing film 2 or the polarizing film 2 ′ was fixed to an automatic winding machine (not shown), and peeled off at a peeling angle of 150 ° and a peeling speed of 30 m / min. The potential of the surface of the adherend (the polarizing film 2 or the polarizing film 2 ′) generated at this time is fixed at a position 30 mm high from the center of the polarizing film 2 or the polarizing film 2 ′. "Initial exfoliation voltage" was measured with a model "STATIRON DZ-4" manufactured by Electrostatic Co., Ltd.). The measurement was performed in an environment of 23 ° C. and 50% RH.

<Measurement of peeling voltage at 70 ° C storage>
The surface protective film 1 according to each example was cut into a size of 70 mm in width and 130 mm in length, and after peeling off the release liner, bonded to a glass plate, a polarizing film with a reflective polarizing film having a width of 70 mm and a length of 100 mm. 2, one end of the surface protective film is provided on the surface of the reflective polarizing film or on the surface of the polarizing film 2 '(no reflective polarizing film, not shown). It was pressed by a hand roller so as to protrude 30 mm from the part (see FIG. 1).
After leaving this sample in a 70 ° C. environment for one day, it was set at a predetermined position on a sample fixing table 3 having a height of 20 mm as shown in FIG. The end of the surface protective film 1 protruding 30 mm from the polarizing film 2 or the polarizing film 2 'was fixed to an automatic winding machine (not shown), and peeled at a peeling angle of 150 ° and a peeling speed of 30 m / min. At this time, the potential of the surface of the adherend (the polarizing film 2 or the polarizing film 2 ′) generated at this time is fixed at a position 30 mm high from the center of the polarizing film 2 or the polarizing film 2 ′. The “static discharge voltage at 70 ° C. storage” was measured using a model “STATIRON DZ-4” manufactured by Electrostatic Co., Ltd.). The measurement was performed in an environment of 23 ° C. and 50% RH.

  The initial value of the polarizing film with the reflective polarizing film, and the absolute value of the peeling voltage after leaving at 70 ° C. for 1 day, preferably 0.7 kV or less, more preferably 0.6 kV or less. Yes, more preferably 0.5 kV or less. When the voltage is 0.7 kV or less, even in the case of a reflective polarizing film, whitening of the panel can be suppressed, and the working efficiency is not impaired, which is a preferable embodiment.

  In addition, the absolute value of the peeling voltage at the initial stage of the polarizing film (without the reflective polarizing film) and after leaving at 70 ° C. for 1 day is preferably 0.7 kV or less, more preferably 0 kV or less. 0.6 kV or less, and more preferably 0.5 kV or less. When it is 0.7 kV or less, whitening of the panel can be suppressed, and the working efficiency is not impaired, which is a preferable embodiment.

  According to the above-mentioned method, the peeling voltage of the polarizing film with the anti-reflective polarizing film of the produced surface protective film and the peeling electrostatic potential of the anti-polarizing film (without the reflective polarizing film) were measured and evaluated. Table 2 shows the obtained results.

Note) The number of parts of the ionic compound and the like indicates the blending amount with respect to 100 parts by weight of the polymer.

The abbreviations in Table 1 are described below.
<Ionic compound>
EMITFSI: ionic liquid, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (manufactured by Tokyo Chemical Industry Co., Ltd.)
BMPyTFSI: ionic liquid, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide (Nippon Carlit)
BMPyTFS: ionic liquid, 1-butyl-3-methylpyridinium trifluoromethanesulfonic acid (manufactured by Nippon Carlit Co., Ltd.)
EMISI: Ionic liquid, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (Daiichi Kogyo Seiyaku)
MPPTFSI: Ionic liquid, 1-methyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide (Toyo Gosei Co., Ltd.)
TMPATFSI: Ionic liquid: Trimethylpropylammonium bis (trifluoromethanesulfonyl) imide (Toyo Gosei Co., Ltd.)
MTOATFSI: ionic liquid, methyltrioctylammonium bis (trifluoromethanesulfonyl) imide (manufactured by Wako Pure Chemical Industries, Ltd.)
LiTFS: alkali metal salt, lithium trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.)
<Silicone component>
KF-353: organopolysiloxane having an oxyalkylene chain (trade name: KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.)
X-40-2450: Ionic group-containing silicone (Shin-Etsu Chemical Co., Ltd., trade name: X-40-2450)
<Fluorine oligomer>
F-562: Fluorine oligomer (trade name: Megafac F-562, manufactured by DIC)

  From the results in Table 2 above, in all the examples, the initial and, after high-temperature heating (leaving at 70 ° C. for 1 day), the peeling electrostatic voltage can be kept low, and as in the reflective polarizing film having a multilayer structure, Excellent peeling antistatic properties could be confirmed for optical films that are easily charged.

  On the other hand, in the comparative example, since no specific ionic compound was used, it was confirmed that the peeling electrostatic voltage to the polarizing film was suppressed. It was confirmed that the peeling voltage after heating at a high temperature (leaving at 70 ° C. for one day) showed a high value. In addition, from the results of the peeling voltage on the polarizing film, even if the peeling antistatic property for the polarizing film is included in the desired range, the peeling antistatic property for the reflective polarizing film is inferior to the examples. It was also confirmed that the reflective polarizing film having a multilayer structure was easily charged, and was hardly removed.

DESCRIPTION OF SYMBOLS 1 Surface protective film 2 Polarizing film with reflective polarizing film 2 'Polarizing film 3 Fixing table 4 Potentiometer 10 Antistatic layer 20 Base film 30 Adhesive layer 40 Reflective polarizing film 50 Adhesive layer 60 Polarizer 70 Conductivity Adhesive layer (B)

Claims (5)

  A pressure-sensitive adhesive composition for a reflective polarizing film, comprising a ionic compound which is liquid at room temperature (25 ° C.) and has a viscosity (25 ° C.) of 550 mPa · s or less, and a pressure-sensitive adhesive polymer. .   2. The reflective polarizing film according to claim 1, wherein the adhesive polymer is at least one selected from the group consisting of a (meth) acryl-based polymer, a urethane-based polymer, and a silicone-based polymer. 3. Adhesive composition.   The pressure-sensitive adhesive composition for a reflective polarizing film according to claim 1, further comprising a silicone component.   A surface protective film for a reflective polarizing film, comprising a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition according to any one of claims 1 to 3 on at least one surface of a substrate film.   An optical film, comprising: the surface protective film for a reflective polarizing film according to claim 4; and a reflective polarizing film.