JP2015120337A - Surface protection film, method for manufacturing surface protection film, and optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface protection film achieving antistatic property and stability in a peeling electrostatic potential with time, a method for manufacturing the surface protection film, and an optical member.SOLUTION: A surface protection film 1 includes a substrate 12 having a first surface and a second surface, an antistatic layer 11 disposed on the first surface of the substrate 12, and a pressure-sensitive adhesive layer 13 disposed on the second surface of the substrate 12. The antistatic layer is formed of an antistatic composition comprising a polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate crosslinking agent as a crosslinking agent. The antistatic composition further contains a fatty acid amide as a slip additive. The substrate 12 is a polyester film. The pressure-sensitive adhesive composition comprises at least one compound selected from an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, and a silicone pressure-sensitive adhesive, and further an antistatic component.

Description

  The present invention relates to a surface protective film, a method for producing the surface protective film, and an optical member.

  The present invention includes a base material having a first surface and a second surface, an antistatic layer provided on the first surface of the base material, and an adhesive layer provided on the second surface of the base material. In detail, it is related with the surface protection film provided with the antistatic function. The surface protective film according to the present invention is suitable for applications that are affixed to plastic products and the like that are likely to generate static electricity. In particular, as a surface protective film used for the purpose of protecting the surface of an optical member (for example, a polarizing plate, a wave plate, a phase difference plate, an optical compensation film, a reflection sheet, a brightness enhancement film used in a liquid crystal display). Useful.

  A surface protective film (also referred to as a surface protective sheet) generally has a configuration in which an adhesive layer is provided on a film-like substrate (support). Such a protective film is bonded to an adherend (protected body) through the pressure-sensitive adhesive layer, and is used for the purpose of protecting the adherend from scratches and dirt during processing and transportation. For example, a panel of a liquid crystal display is formed by bonding an optical member such as a polarizing plate or a wave plate to a liquid crystal cell via an adhesive layer. In the manufacture of such a liquid crystal display panel, a polarizing plate to be bonded to a liquid crystal cell is once manufactured in a roll form, and then unwound from this roll and cut into a desired size according to the shape of the liquid crystal cell. . Here, in order to prevent the polarizing plate from being rubbed and scratched with a transport roll or the like in an intermediate step, a measure is taken to attach a surface protective film to one side or both sides (typically, one side) of the polarizing plate. This surface protective film is peeled off and removed when it is no longer needed.

  In general, since the surface protective film and the optical member are made of a plastic material, they have high electrical insulation and generate static electricity due to friction or peeling. For this reason, static electricity tends to be generated even when the surface protective film is peeled off from the optical member such as a polarizing plate, and when voltage is applied to the liquid crystal with this static electricity remaining, the alignment of the liquid crystal molecules is lost, There is also a concern that the panel may be lost. Also, the presence of static electricity can be a factor that attracts dust and reduces workability. Under such circumstances, the surface protection film is subjected to an antistatic treatment. For example, as a surface layer (topcoat layer, back layer) of the surface protection film, an antistatic layer is formed or an antistatic coating is applied. Thus, an antistatic function is provided (see Patent Documents 1 and 2).

  In recent years, PEDOT (poly (3,4-ethylenedioxythiophene) / PSS (polystyrene sulfonate) (polythiophene type) system is used as a conductive polymer used to impart an antistatic function to the surface layer of the surface protective film. However, if the water dispersion type is stored in a solution state, agglomerates are generated, and a uniform antistatic layer cannot be formed. In addition, when an antistatic layer is formed using the conductive polymer, PSS (corresponding to a dopant) is desorbed from PEDOT with the passage of time, and the surface resistance value and peeling band voltage are reduced. In addition, there is a risk that problems such as an increase in surface resistance (deterioration) due to oxidation deterioration or light deterioration may occur.

  In addition, when an increase (deterioration) in the surface resistance value or the like occurs, static electricity is generated when the surface protective film is peeled off from the adherend, which may cause a problem.

JP 2004-223923 A JP 2008-255332 A

  Accordingly, in view of the above circumstances, the present invention provides a surface protective film, a method for producing the surface protective film, and an optical member that can achieve antistatic properties and stability over time of the stripping voltage, as a result of earnest research. Objective.

  That is, the surface protective film of the present invention has a substrate having a first surface and a second surface, an antistatic layer provided on the first surface of the substrate, and an adhesive to the second surface of the substrate. A surface protective film comprising a pressure-sensitive adhesive composition, wherein the antistatic layer comprises polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based cross-linking agent as a cross-linking agent. It is formed from the antistatic agent composition containing this.

  In the surface protective film of the present invention, the antistatic agent composition preferably further contains a fatty acid amide as a lubricant.

  In the surface protective film of the present invention, the base material is preferably a polyester film.

  In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains at least one selected from the group consisting of an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive.

  In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains an antistatic component.

  The optical member of the present invention is preferably protected by the surface protective film.

  The method for producing a surface protective film of the present invention is a method for producing the surface protective film, comprising: preparing an aqueous solution containing the antistatic agent composition; and applying the aqueous solution to the first surface of the substrate. And drying to prepare an antistatic layer.

  In the surface protective film of the present invention, the antistatic layer provided on the first surface (back surface) of the base material is an antistatic agent composition containing a specific conductive polymer component, a binder, and a crosslinking agent. As a result, it is possible to form a uniform antistatic layer, excellent workability, and furthermore, a surface protection film and surface protection that can achieve antistatic properties based on the antistatic layer and stability over time of the stripping voltage. A film production method and an optical member can be provided and are useful.

It is typical sectional drawing which shows one structural example of the surface protection film which concerns on this invention. It is explanatory drawing which shows the measuring method of peeling voltage.

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

<Overall structure of surface protective film>
The surface protective film disclosed herein is generally in the form of a pressure-sensitive adhesive sheet, pressure-sensitive adhesive tape, pressure-sensitive adhesive label, pressure-sensitive adhesive film or the like, and in particular, an optical component (for example, a liquid crystal display panel such as a polarizing plate or a wave plate) It is suitable as a surface protective film for protecting the surface of the optical component during processing or transportation of the optical component used as a component. The pressure-sensitive adhesive layer in the surface protective film is typically formed continuously, but is not limited to such a form, and is formed in a regular or random pattern such as a spot or stripe. It may be an adhesive layer. In addition, the surface protective film disclosed herein may be in the form of a roll or a single sheet.

  A typical configuration example of the surface protective film disclosed herein is schematically shown in FIG. The surface protective film 1 includes a base material (for example, a polyester film) 12, an antistatic layer 11 provided on the first surface 12, and a second surface of the base material 12 (on the side opposite to the antistatic layer 11). And a pressure-sensitive adhesive layer 13 provided on the surface). The surface protective film 1 is used by sticking the pressure-sensitive adhesive layer 13 to an adherend (a surface to be protected, for example, the surface of an optical component such as a polarizing plate). The surface protective film 1 before use (that is, before sticking to the adherend) is peeled so that the surface of the pressure-sensitive adhesive layer 13 (sticking surface to the adherend) is at least the pressure-sensitive adhesive layer 13 side. It may be in a form protected by a liner. Alternatively, even when the surface protective film 1 is wound in a roll shape, the pressure-sensitive adhesive layer 13 comes into contact with the back surface of the base material 12 (the surface of the antistatic layer 11) and the surface thereof is protected. Good.

  As shown in FIG. 1, the antistatic layer 11 is formed directly on the first surface of the substrate 12 (without any other layer), and the antistatic layer 11 is exposed on the back surface of the surface protective film 1. (In other words, the mode in which the antistatic layer 11 also serves as a topcoat layer) is provided with an antistatic layer in which the antistatic layer 11 is provided on the substrate 12 as compared with the configuration in which the antistatic layer is provided separately from the topcoat layer. A film (and thus a surface protective film using the film) is advantageous from the viewpoint of improving productivity because the number of layers constituting the surface protective film can be reduced.

<Base material>
The surface protective film of the present invention has a base material having a first surface (back surface) and a second surface (surface opposite to the first surface). In the technology disclosed herein, the resin material constituting the substrate can be used without any particular limitation. For example, transparency, mechanical strength, thermal stability, moisture shielding property, isotropic property, flexibility It is preferable to use a material excellent in properties such as property and dimensional stability. In particular, since the base material has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like, and can be wound into a roll shape, which is useful.

  Examples of the substrate (support) 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; An acrylic polymer such as methyl methacrylate; and the like, a plastic film composed of a resin material having a main resin component (a main component of the resin component, typically a component occupying 50% by mass or more) as the base material It can be preferably used. Other examples of the resin material include styrene polymers such as polystyrene and acrylonitrile-styrene copolymers; olefin polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers; Examples of the resin material include vinyl chloride polymers; amide polymers such as nylon 6, nylon 6,6, and aromatic polyamide. Still other examples of the resin material include imide polymers, sulfone polymers, polyether sulfone polymers, polyether ether ketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers. , Arylate polymers, polyoxymethylene polymers, epoxy polymers and the like. The base material which consists of 2 or more types of blends of the polymer mentioned above may be sufficient.

  As the substrate, a plastic film made of a transparent thermoplastic resin material can be preferably used. Among the plastic films, it is more preferable to use a polyester film. Here, the polyester film is one having 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 as a main resin component. Say. Such a polyester film has preferable properties as a substrate for a surface protective film, such as excellent optical properties and dimensional stability, and has a property of being easily charged as it is.

  Various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, and a colorant (pigment, dye, etc.) may be blended in the resin material constituting the substrate as necessary. For example, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer are applied to the first surface of the polyester film (the surface on which the antistatic layer is provided). The surface treatment may be performed. Such a surface treatment can be, for example, a treatment for enhancing the adhesion between the substrate and the antistatic layer. A surface treatment in which a polar group such as a hydroxyl group (—OH group) is introduced on the surface of the substrate can be preferably employed. Moreover, the surface treatment similar to the above may be given to the 2nd surface (surface by which the adhesive layer is formed) of a base material. Such a surface treatment may be a treatment for enhancing the adhesion between the film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

  The surface protective film of the present invention has an antistatic function by having an antistatic layer on the base material, but it is also possible to use a plastic film that has undergone antistatic treatment as the base material. is there. The use of the substrate is preferable because the surface protection film itself can be prevented from being charged when peeled off. Moreover, the base material is a plastic film, and by applying an antistatic treatment to the plastic film, it is possible to reduce the surface protection film itself and to have an excellent antistatic ability to the adherend. In addition, there is no restriction | limiting in particular as a method to provide an antistatic function, A conventionally well-known method can be used, for example, antistatic resin which consists of an antistatic agent and a resin component, a conductive polymer, and a conductive substance. Examples thereof include a method of applying a conductive resin, a method of depositing or plating a conductive material, a method of kneading an antistatic agent, and the like.

  As thickness of the said base material, it is 5-200 micrometers normally, Preferably it is about 10-100 micrometers. When the thickness of the base material is within the above range, it is preferable because the workability for bonding to the adherend and the workability for peeling from the adherend are excellent.

<Antistatic layer (topcoat layer)>
The surface protective film of the present invention is provided on a base material having a first surface (back surface) and a second surface (surface opposite to the first surface), and the first surface (back surface) of the base material. A surface protection film comprising an antistatic layer and an adhesive layer formed of an adhesive composition on the second surface of the substrate, wherein the antistatic layer is polyanilinesulfonic acid as a conductive polymer component And an antistatic agent composition containing a polyester resin as a binder and an isocyanate crosslinking agent as a crosslinking agent. When the surface protective film has an antistatic layer (topcoat layer), the antistatic property of the surface protective film and the stability over time of the stripping voltage are improved, which is a preferred embodiment.

<Conductive polymer>
The antistatic layer contains polyaniline sulfonic acid as a conductive polymer component. By using the conductive polymer, the antistatic property based on the antistatic layer and the peel voltage over time can be satisfied. The polyaniline sulfonic acid is “water-soluble”, but can be fixed in the antistatic layer by using an isocyanate-based crosslinking agent described later, and water resistance can be improved. By using the water-soluble conductive polymer-containing aqueous solution, an antistatic layer having an excellent surface resistance value with time can be obtained, which is a preferred embodiment. On the other hand, when the conductive polymer used in forming the antistatic layer is “water-dispersible”, aggregates are generated when the antistatic layer is formed using the water-dispersible conductive polymer-containing solution. This is not preferable because it tends to be easy and cannot be applied uniformly, and the surface resistance value with time tends to be extremely inferior.

  The amount of the conductive polymer used is preferably 10 to 200 parts by weight, more preferably 25 to 150 parts by weight, and still more preferably, with respect to 100 parts by weight of the binder contained in the antistatic layer (topcoat layer). Is 40-120 parts by mass. If the amount of the conductive polymer used is too small, the antistatic effect may be reduced. If the amount of the conductive polymer used is too large, the adhesion of the antistatic layer to the substrate may be reduced, or the transparency may be reduced. There is a risk of lowering, which is not preferable.

The polyaniline sulfonic acid used as the conductive polymer component preferably has a polystyrene equivalent weight average molecular weight (Mw) of 5 × 10 ⁵ or less, more preferably 3 × 10 ⁵ or less. In addition, 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.

As a method of forming the antistatic layer, a method of applying and drying (or curing) a coating material for forming the antistatic layer on the first surface of the base material (support) can be adopted. The conductive polymer component contains polyaniline sulfonic acid, a polyester resin as a binder, and an isocyanate crosslinking agent as a crosslinking agent as essential components, and the essential component is dissolved in water (conductive polymer aqueous solution). Or simply referred to as an aqueous solution). Such an aqueous conductive polymer solution is prepared by, for example, dissolving a conductive polymer having a hydrophilic functional group (which can be synthesized by a method such as copolymerizing a monomer having a hydrophilic functional group in the molecule) in water. can do. Examples of the hydrophilic functional group include a sulfo group, amino group, amide group, imino group, hydroxyl group, mercapto group, hydrazino group, carboxyl group, quaternary ammonium group, sulfate group (—O—SO ₃ H), phosphorus An acid ester group (for example, —O—PO (OH) ₂ ) and the like are exemplified. Such hydrophilic functional groups may form a salt.

  Moreover, as a commercial item of the said polyaniline sulfonic acid aqueous solution, Mitsubishi Rayon Co., Ltd. brand name "aqua-PASS" etc. are illustrated.

  The antistatic layer disclosed herein contains polyaniline sulfonic acid (polyaniline type) as an essential component as the conductive polymer component. For example, one or more other antistatic components (conductive polymer) Organic conductive materials other than the above, inorganic conductive materials, antistatic agents, etc.) may be included together. In a preferred embodiment, the antistatic layer contains substantially no antistatic component other than the conductive polymer, that is, the antistatic component contained in the antistatic layer is substantially only a conductive polymer. The embodiment consisting of can be implemented more preferably.

  Examples of the organic conductive substance include cation type antistatic agents having a cationic functional group such as a quaternary ammonium salt, a pyridinium salt, a primary amino group, a secondary amino group, and a tertiary amino group; sulfonates and sulfates Anionic antistatic agents having an anionic functional group such as salts, phosphonates, phosphate esters; amphoteric ionic antistatic agents such as alkylbetaines and their derivatives, imidazolines and their derivatives, alanine and their derivatives; amino alcohols Nonionic antistatic agents such as glycerin and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof; polymerization of monomers having the cation type, anion type or zwitterion type ion conductive groups (for example, quaternary ammonium base) Or an ion conductive polymer obtained by copolymerization; poly Include; thiophene, polyaniline, polypyrrole, polyethylene imine, a conductive polymer such as an allylamine polymer. Such an antistatic agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the inorganic conductive material include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, Examples thereof include copper iodide, ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide), and the like. Such inorganic conductive materials may be used alone or in combination of two or more.

  Examples of the antistatic agent include a cationic antistatic agent, an anionic antistatic agent, an amphoteric ion antistatic agent, a nonionic antistatic agent, and a single ion having a cationic, anionic or zwitterionic ion conductive group. Examples thereof include an ion conductive polymer obtained by polymerizing or copolymerizing a monomer.

<Binder>
The antistatic layer contains a polyester resin as an essential component as a binder. The polyester resin is preferably a resin material containing polyester as a main component (typically exceeding 50% by mass, preferably 75% by mass or more, for example, 90% by mass or more). The polyester typically includes polyvalent carboxylic acids (typically dicarboxylic acids) having two or more carboxyl groups in one molecule and derivatives thereof (an anhydride, esterified product, halogenated product of the polyvalent carboxylic acid). Selected from one or two or more compounds (polyhydric carboxylic acid component) selected from, and polyhydric alcohols (typically diols) having two or more hydroxyl groups in one molecule. It is preferable to have a structure in which one or more compounds (polyhydric alcohol component) are condensed.

  Examples of compounds that can be employed as the polyvalent 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, dimethyl Adipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6-tetramethylsuberic acid, azelaic acid, sebacic acid, perfluoro Sebacic acid, brassic acid, dodecyl dicar Aliphatic dicarboxylic acids such as acid, tridecyl dicarboxylic acid, tetradecyl dicarboxylic acid; cycloalkyl dicarboxylic acid (for example, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4- (2- Alicyclic dicarboxylic acids such as norbornene) dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantane dicarboxylic acid, spiroheptane dicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, methylisophthalic acid, Dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorenedicarboxylic acid, anthracenedical Bonic acid, biphenyl dicarboxylic acid, biphenylene dicarboxylic acid, dimethyl biphenylene dicarboxylic acid, 4,4 "-p-terephenylene dicarboxylic acid, 4,4" -p-quarelphenyl dicarboxylic acid, bibenzyl dicarboxylic acid, azobenzene dicarboxylic acid, Homophthalic acid, phenylenediacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyldiacetic acid, biphenyldipropionic acid, 3,3 ′-[4,4 ′-(methylenedi-p-biphenylene) dipropion Aromatic dicarboxylic acids such as acid, 4,4′-bibenzyldiacetic acid, 3,3 ′ (4,4′-bibenzyl) dipropionic acid, oxydi-p-phenylenediacetic acid; Acid anhydrides of any of the polyhydric carboxylic acids mentioned above (Eg alkyl esters). It can be a monoester, a diester or the like. ); Acid halides corresponding to any of the polyvalent carboxylic acids described above (for example, dicarboxylic acid chloride); and the like.

  Preferable examples of the compound that can be employed as the polyvalent carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and acid anhydrides thereof; adipic acid, sebacic acid, azelaic acid, succinic acid, Aliphatic dicarboxylic acids such as fumaric acid, maleic acid, hymic acid, 1,4-cyclohexanedicarboxylic acid, and acid anhydrides thereof; and lower alkyl esters of the dicarboxylic acids (for example, monoalcohols having 1 to 3 carbon atoms) Ester) and the like.

  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, and 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- Diols such as 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A, and bisphenol A Is mentioned. Other examples include alkylene oxide adducts (for example, ethylene oxide adducts, propylene oxide adducts, etc.) of these compounds.

The molecular weight of the polyester resin is, for example, about 5 × 10 ^{3 to} 1.5 × 10 ⁵ (preferably 1 × 10 5) as a weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography (GPC). ^4-6 × 10 ⁴ ). Moreover, the glass transition temperature (Tg) of the said polyester resin can be 0-120 degreeC (preferably 10-80 degreeC), for example.

  As the polyester resin, a commercially available product name “Vylonal” manufactured by Toyobo Co., Ltd. can be used.

  The antistatic layer (topcoat layer) is a resin other than a polyester resin (for example, acrylic) as a binder as long as the performance of the surface protective film disclosed herein (for example, performance such as antistatic properties) is not significantly impaired. Resin, acrylic resin, acrylic styrene resin, acrylic silicone resin, silicone resin, polysilazane resin, polyurethane resin, fluororesin, polyolefin resin and the like. A preferred embodiment of the technology disclosed herein is a case where the binder of the antistatic layer is substantially composed only of a polyester resin. For example, the antistatic layer whose ratio of the polyester resin to a binder is 98-100 mass% is preferable. The proportion of the binder in the entire antistatic layer can be, for example, 50 to 95% by mass, and usually 60 to 90% by mass is appropriate.

<Lubricant>
The antistatic layer (topcoat layer) in the technique disclosed herein is preferably a fatty acid amide as a lubricant. By using fatty acid amide as a lubricant, a further release treatment (for example, a treatment in which a known release treatment agent such as a silicone release agent or a long-chain alkyl release agent is applied and dried) is applied to the surface of the antistatic layer. Even in the case where the coating is not performed, an antistatic layer (topcoat layer) having both sufficient slipping property and printing adhesion can be obtained, which can be a preferable mode. Thus, the aspect in which the surface of the antistatic layer is not further peeled can prevent whitening due to the peeling treatment agent (for example, whitening due to storage under heating and humidification conditions). This is preferable. It is also advantageous from the viewpoint of solvent resistance.

  Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, N-oleylparticic acid amide, 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 lauric acid amide, ethylene bis stearic acid Amides, ethylene bishydroxystearic acid amides, ethylene bisbehenic acid amides, hexamethylene bisstearic acid amides, hexamethylene bisbehenic acid amides, hexamethylene hydroxystearic acid amides N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl Examples include adipic acid amide, N, N′-dioleyl sebacic acid amide, m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N, N′-stearyl isophthalic acid amide, and the like. These lubricants may be used alone or in combination of two or more.

  The ratio of the lubricant to the whole antistatic layer can be 1 to 50% by mass, and usually 5 to 40% by mass is appropriate. When there is too little content rate of a lubricant, it exists in the tendency for slipperiness to fall easily. If the content of the lubricant is too large, the print adhesion may be lowered.

  The technique disclosed herein can be carried out in a mode in which the antistatic layer (topcoat layer) contains other lubricant in addition to the fatty acid amide, as long as the application effect is not greatly impaired. Examples of such other lubricants include various waxes such as petroleum wax (paraffin wax, etc.), mineral wax (montan wax, etc.), higher fatty acid (cellotic acid, etc.), and neutral fat (palmitic acid triglyceride, etc.). It is done. Alternatively, in addition to the wax, a general silicone-based lubricant, a fluorine-based lubricant, and the like may be supplemented. The technology disclosed herein can be preferably implemented in an embodiment that does not substantially contain such a silicone-based lubricant, a fluorine-based lubricant and the like. However, as long as the application effect of the technology disclosed herein is not significantly impaired, the inclusion of a silicone compound used for a purpose other than the lubricant (for example, as an antifoaming agent for a coating material for forming an antistatic layer described later) Is not to be excluded.

<Crosslinking agent>
The antistatic layer contains an isocyanate-based crosslinking agent as a crosslinking agent. By using the isocyanate-based crosslinking agent, the water-soluble polyaniline sulfonic acid, which is an essential component when forming the antistatic layer, can be fixed in the binder, has excellent water resistance, and further improves printing adhesion. The effect can be realized.

  In addition, as the isocyanate-based crosslinking agent, it is preferable to use a blocked isocyanate-based crosslinking agent that is stable even in an aqueous solution. Specific examples of the blocked isocyanate-based crosslinking agent include isocyanate-based crosslinking agents that can be used in the preparation of general pressure-sensitive adhesive layers and antistatic layers (topcoat layers) (for example, pressure-sensitive adhesive layers described later). Isocyanate compounds (isocyanate-based cross-linking agents)) alcohols, phenols, thiophenols, amines, imides, oximes, lactams, active methylene compounds, mercaptans, imines, ureas, diaryl compounds And those blocked with sodium bisulfite can be used.

  The antistatic layer in the technique disclosed herein may contain other antistatic components, antioxidants, colorants (pigments, dyes, etc.), fluidity modifiers (thixotropic agents, thickeners, etc.), if necessary. It may contain additives such as film-forming aids, surfactants (such as antifoaming agents), and preservatives.

<Formation of antistatic layer>
The antistatic layer (topcoat layer) is a liquid composition (for forming an antistatic layer) in which essential components such as the conductive polymer component and additives used as necessary are dissolved in an appropriate solvent (such as water). Can be suitably formed by a technique including applying a coating material, an antistatic agent composition) to a substrate. For example, a method of applying the coating material to the first surface of the substrate and drying it, and performing a curing treatment (heat treatment, ultraviolet treatment, etc.) as necessary can be preferably employed. The NV (nonvolatile content) of the coating material can be, for example, 5% by mass or less (typically 0.05 to 5% by mass), and usually 1% by mass or less (typically 0.10 to 10%). 1 mass%) is appropriate. In the case of 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 mass% (for example, 0.10 to 0.40 mass%). Thus, a more uniform antistatic layer can be formed by using a low NV coating material.

  As the solvent constituting the coating material for forming the antistatic layer, a solvent capable of stably dissolving the components for forming the antistatic layer is preferable. Such a 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 such as n-hexane and cyclohexane. Hydrocarbons; aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, and cyclohexanol; alkylene glycol monoalkyl ether (for example, ethylene glycol monomethyl ether) , Ethylene glycol monoethyl ether), glycol ethers such as dialkylene glycol monoalkyl ether; and the like can be used. In a preferred embodiment, the solvent of the coating material is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol).

<Properties of antistatic layer>
The thickness of the antistatic layer in the technique disclosed herein is typically 3 to 500 nm, preferably 3 to 100 nm, and more preferably 3 to 60 nm. If the thickness of the antistatic layer is too small, it becomes difficult to form the antistatic layer uniformly (for example, the thickness of the antistatic layer varies greatly depending on the location). Unevenness may be likely to occur. On the other hand, if it is too thick, the properties of the substrate (optical properties, dimensional stability, etc.) may be affected.

In a preferred embodiment of the surface protective film disclosed herein, the surface resistance value (Ω / □) measured on the surface of the antistatic layer is preferably less than 1.0 × 10 ¹¹ , more preferably. , 5.0 × 10 ^{10 or} less, and more preferably 1.0 × 10 ^{10 or} less. A surface protective film exhibiting a surface resistance value within the above range can be suitably used as a surface protective film used in the processing or transporting of articles that dislike static electricity such as liquid crystal cells and semiconductor devices. The surface resistance value can be calculated from the surface resistance value measured under an atmosphere of 23 ° C. and 50% RH using a commercially available insulation resistance measuring device.

  The surface protective film disclosed herein preferably has a property that the back surface (surface of the antistatic layer) can be easily printed with water-based ink or oil-based ink (for example, using an oil-based marking pen). Such a surface protective film has an identification number or the like of the adherend to be protected in the process of transporting the adherend (for example, an optical component) performed in a state in which the surface protective film is attached. Suitable for describing and displaying. Therefore, it is preferable that the surface protective film has excellent printability. For example, it is preferable that the solvent is alcohol-based and has high printability for oil-based inks containing pigments. Moreover, it is preferable that the printed ink is difficult to be removed by rubbing or transfer (that is, excellent in print adhesion). The surface protective film disclosed herein may also have a solvent resistance that does not cause a noticeable change in appearance even if the print is wiped with alcohol (for example, ethyl alcohol) when correcting or erasing the print. preferable.

  The surface protective film disclosed herein can be implemented in an embodiment including other layers in addition to the base material, the pressure-sensitive adhesive layer, and the antistatic layer. Examples of the arrangement of the “other layer” include a space between the first surface (back surface) of the substrate and the antistatic layer, a space between the second surface (front surface) of the substrate and the pressure-sensitive adhesive layer, and the like. The layer disposed between the back surface of the substrate and the antistatic layer can be, for example, a layer containing an antistatic component (the above-described antistatic layer). The layer disposed between the front surface of the substrate and the pressure-sensitive adhesive layer can be, for example, an undercoat layer (anchor layer) or an antistatic layer that enhances the anchoring property of the pressure-sensitive adhesive layer with respect to the second surface. It may be a surface protective film having a configuration in which an antistatic layer is disposed on the front surface of the substrate, an anchor layer is disposed on the antistatic layer, and an adhesive layer is disposed thereon.

<Adhesive composition>
The surface protective film of the present invention has the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, and as the pressure-sensitive adhesive composition, if it has adhesiveness, Can be used without particular limitation, for example, acrylic pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, synthetic rubber-based pressure-sensitive adhesive, natural rubber-based pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, etc. can be used. It is at least one selected from the group consisting of a pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive, and particularly preferably, an acrylic pressure-sensitive adhesive using a (meth) acrylic polymer is used. .

  When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, the (meth) acrylic polymer constituting the acrylic pressure-sensitive adhesive has an alkyl group having 1 to 14 carbon atoms as a raw material monomer constituting the acrylic pressure-sensitive adhesive (meta ) Acrylic monomers can be used. As said (meth) acrylic-type monomer, 1 type (s) or 2 or more types can be used as a main component. By using the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend (protected body) to be low, and light releasability and re-peeling. A surface protective film having excellent properties 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 acrylate and / or methacrylate. Further, the “main component” in the present invention means the largest component in the total amount of constituent components, preferably more than 40% by mass, more preferably more than 50% by mass, and still more preferably 60% by mass. It means exceeding%.

  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, 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, etc. It is done.

  Among these, the surface protective film of the present invention includes hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl. 6 to 14 carbon atoms such as (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate and the like. A (meth) acrylic monomer having an alkyl group is preferred. In particular, by using a (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend to be low, and the removability is excellent.

  In particular, it is preferable to contain 50% by mass or more of a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms with respect to 100% by mass of the total amount of monomer components constituting the (meth) acrylic polymer. More preferably, it is 60 mass% or more, More preferably, it is 70 mass% or more, Most preferably, it is 80-93 mass%. If it is less than 50% by mass, the appropriate wettability of the pressure-sensitive adhesive composition and the cohesive strength of the pressure-sensitive adhesive layer will be inferior, which is not preferable.

  In the pressure-sensitive adhesive composition of the present invention, the (meth) acrylic polymer preferably contains a (meth) acrylic monomer having a hydroxyl group as a raw material monomer. As said (meth) acrylic-type monomer which has the said hydroxyl group, 1 type (s) or 2 or more types can be used as a main component.

  By using the (meth) acrylic monomer having a hydroxyl group, it is easy to control the crosslinking of the pressure-sensitive adhesive composition, and it is easy to control the balance between the improvement of wettability by flow and the reduction of the adhesive strength in peeling. Become. Furthermore, unlike carboxyl groups and sulfonate groups that can generally act as crosslinking sites, hydroxyl groups have moderate interactions with ionic compounds that are antistatic components (antistatic agents) and organopolysiloxanes having oxyalkylene chains. Therefore, it can be suitably used also in terms of antistatic properties.

  Examples of the (meth) acrylic monomer having a hydroxyl group 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, vinyl alcohol, Examples include allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. In particular, it is preferable to use a (meth) acrylic monomer having a hydroxyl group having 4 or more carbon atoms in the alkyl group, since light release at the time of high-speed peeling is easy.

  It is preferable to contain 15% by mass or less of the (meth) acrylic monomer having a hydroxyl group with respect to 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. Is 1 to 13% by mass, more preferably 2 to 11% by mass, and most preferably 3.5 to 10% by mass. Within the above range, the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the resulting pressure-sensitive adhesive layer can be easily controlled, which is preferable.

  In addition, as another polymerizable monomer component, the Tg is 0 ° C. or lower (usually −100 ° C. or higher) for the reason that it is easy to balance the adhesive performance, and the glass transition temperature or peeling of the (meth) acrylic polymer. A polymerizable monomer or the like for adjusting the property can be used as long as the effects of the present invention are not impaired.

  As other polymerizable monomers other than the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer and the (meth) acrylic monomer having a hydroxyl group, A (meth) acrylic monomer having a carboxyl group can be used.

  Examples of the (meth) acrylic monomer having a carboxyl group include (meth) acrylic acid, carboxylethyl (meth) acrylate, carboxylpentyl (meth) acrylate, itaconic acid, maleic acid, and fumaric acid.

  The (meth) acrylic monomer having a carboxyl group is preferably 10 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. More preferably, the amount is less than 3 parts by weight, more preferably less than 3 parts by weight, and most preferably less than 0.01 part by weight and less than 1 part by weight. When the amount exceeds 10 parts by mass, a large number of acid functional groups such as carboxyl groups having a large polar action exist, and when an ionic compound is blended as an antistatic component, an acid functional group such as a carboxyl group is included in the ionic compound. By interacting with each other, ion conduction is hindered, conductivity efficiency is lowered, and sufficient antistatic properties may not be obtained, which is not preferable.

  Furthermore, the (meth) acrylic monomer having a C1-C14 alkyl group used in the (meth) acrylic polymer, the (meth) acrylic monomer having a hydroxyl group, and the (meth) having a carboxyl group Other polymerizable monomers other than acrylic monomers can be used without particular limitation as long as they do not impair the characteristics of the present invention. For example, cohesive strength / heat resistance improving components such as cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine In addition, a component having a functional group functioning as an adhesive strength improvement or a crosslinking base point such as a vinyl ether monomer can be appropriately used. These polymerizable monomers may be used alone or in combination of two or more.

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

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

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethyl styrene, α-methyl styrene, other substituted styrenes, and the like.

  Examples of amide group-containing monomers include acrylamide, methacrylamide, diethyl acrylamide, N-vinyl pyrrolidone, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N, N-diethyl acrylamide, N, N-diethyl methacryl. Examples include amide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, and diacetone acrylamide.

  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, N, N-dimethylaminopropyl (meth) acrylate, and the like.

  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, isobutyl vinyl ether, and the like.

  In the present invention, other polymerizable monomers other than the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the (meth) acrylic monomer having a hydroxyl group, and the (meth) acrylic monomer having a carboxyl group are as follows: The amount is preferably 0 to 40 parts by mass, more preferably 0 to 30 parts by mass with respect to 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. By using the other polymerizable monomer within the above range, when an ionic compound is used as an antistatic agent, a good interaction with the ionic compound and a good removability can be appropriately adjusted. .

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

  In addition, the average addition mole number of the oxyalkylene unit of the alkylene oxide group-containing reactive monomer is preferably 1 to 40 from the viewpoint of compatibility with the ionic compound as the antistatic component, and 3 to 40. More preferably, it is more preferably 4 to 35, and particularly preferably 5 to 30. When the average added mole number is 1 or more, the effect of reducing the contamination of the adherend (protected body) tends to be obtained efficiently. Moreover, when the said average addition mole number is larger than 40, since interaction with an ionic compound is large and there exists a tendency for the viscosity of an adhesive composition to rise and for coating to become difficult, it is unpreferable. Note that the terminal of the oxyalkylene chain may be a hydroxyl group or may be substituted with another functional group.

  The alkylene oxide group-containing reactive monomer may be used alone or in combination of two or more, but the total content is the total amount of monomer components of the (meth) acrylic polymer. The content is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, still more preferably 4% by mass or less, and 3% by mass or less. Particularly preferred is 1% by mass or less. When the content of the alkylene oxide group-containing reactive monomer exceeds 10% by mass, the interaction with the ionic compound is increased, ionic conduction is hindered, and the antistatic property is lowered, which is not preferable.

  Examples of the oxyalkylene unit of the alkylene oxide group-containing reactive monomer include those having an alkylene group having 1 to 6 carbon atoms, such as an oxymethylene group, an oxyethylene group, an oxypropylene group, and an oxybutylene group. It is done. The hydrocarbon group of the oxyalkylene chain may be linear or branched.

  The alkylene oxide group-containing reactive monomer is more preferably a reactive monomer having an ethylene oxide group. By using a (meth) acrylic polymer having a reactive monomer having an ethylene oxide group as the base polymer, the compatibility between the base polymer and the ionic compound is improved, and bleeding to the adherend is suitably suppressed, and the A fouling pressure-sensitive adhesive composition is obtained.

  Examples of the alkylene oxide group-containing reactive monomer include (meth) acrylic acid alkylene oxide adducts and reactive surfactants having reactive substituents such as acryloyl group, methacryloyl group, and allyl group in the molecule. can give.

  Specific examples of the (meth) acrylic acid alkylene oxide adduct include, for example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, polyethylene glycol-polybutylene glycol (meth) ) Acrylate, polypropylene glycol-polybutylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, octoxy polyethylene glycol (meth) acrylate, lauroxy polyethylene Glycol (meth) acrylate, stearoxy polyethylene glycol Le (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, octoxypolyethylene glycol - polypropylene glycol (meth) acrylate.

  Specific examples of the reactive surfactant include, for example, an anionic reactive surfactant having a (meth) acryloyl group or an allyl group, a nonionic reactive surfactant, and a cationic reactive surfactant. Can be given.

  The (meth) acrylic polymer preferably has a weight average molecular weight (Mw) of 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, still more preferably 300,000 to 3,000,000. When the weight average molecular weight is smaller than 100,000, the adhesive force tends to be generated due to the reduced cohesive force of the pressure-sensitive adhesive layer. On the other hand, when the weight average molecular weight exceeds 5,000,000, the fluidity of the polymer is lowered, the wetness to the adherend (for example, polarizing plate) becomes insufficient, and the adherend and the pressure-sensitive adhesive layer of the surface protective film It tends to cause blisters that occur during the period. In addition, a weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

  The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C. or lower, more preferably −10 ° C. or lower (usually −100 ° C. or higher). When the glass transition temperature is higher than 0 ° C., the polymer is difficult to flow, for example, the wettability to the polarizing plate becomes insufficient, and it tends to cause blisters generated between the polarizing plate and the pressure-sensitive adhesive layer of the surface protective film. There is. In particular, when the glass transition temperature is set to −61 ° C. or lower, an adhesive layer excellent in wettability to the polarizing plate and light peelability is easily obtained. In addition, the glass transition temperature of a (meth) acrylic-type polymer can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

  The polymerization method of the (meth) acrylic polymer is not particularly limited, and can be polymerized by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. From the viewpoint of characteristics such as low contamination to the adherend (protected body), solution polymerization is a more preferable embodiment. Further, the polymer obtained may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, and the like.

  When the pressure-sensitive adhesive layer uses a urethane-based pressure-sensitive adhesive, any appropriate urethane-based pressure-sensitive adhesive can be adopted as the urethane-based pressure-sensitive adhesive. As such a urethane type adhesive, Preferably, what consists of urethane resin obtained by making a polyol and a polyisocyanate compound react is mentioned. Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, and polycaprolactone polyol. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and the like.

  When the pressure-sensitive adhesive layer uses a silicone-based pressure-sensitive adhesive, any appropriate silicone-based pressure-sensitive adhesive can be adopted as the silicone-based pressure-sensitive adhesive. As such a silicone-based pressure-sensitive adhesive, one obtained by blending or agglomerating a silicone resin can be preferably used.

  Examples of the silicone adhesive include addition reaction curable silicone adhesives and peroxide curable silicone adhesives. Among these silicone pressure-sensitive adhesives, peroxides (benzoyl peroxide and the like) are not used, and decomposition products are not generated. Therefore, an addition reaction curable silicone pressure-sensitive adhesive is preferable.

  As the curing reaction of the addition reaction curable silicone pressure-sensitive adhesive, for example, when obtaining a polyalkyl silicone pressure-sensitive adhesive, generally, a method of curing a polyalkylhydrogensiloxane composition with a platinum catalyst can be mentioned.

<Antistatic component in adhesive layer>
In the surface protective film of the present invention, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer preferably contains an antistatic component, and more preferably contains an ionic compound as the antistatic component. Examples of the ionic compound include alkali metal salts and / or ionic liquids. By containing these ionic compounds, excellent antistatic properties can be imparted. The pressure-sensitive adhesive layer (using the antistatic component) obtained by crosslinking the pressure-sensitive adhesive composition containing the antistatic component as described above is an adherend that is not antistatic when peeled (for example, a polarizing plate) ), And a surface protective film with reduced contamination on the adherend is obtained. For this reason, it becomes very useful as an antistatic surface protective film in a technical field related to optical and electronic components in which charging and contamination are particularly serious problems.

Since the alkali metal salt has high ion dissociation properties, it is preferable in that it exhibits excellent antistatic ability even with a small amount of addition. Examples of the alkali metal salt include a cation composed of Li ⁺ , Na ⁺ , K ⁺ , Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SCN. _{^{-, ClO 4 -, NO 3}} -, CH 3 COO -, C 9 H 19 COO -, CF 3 COO -, C 3 F 7 COO -, CH 3 SO 3 -, CF 3 SO 3 -, C 4 F 9 SO ₃ ⁻ , C ₂ H ₅ OSO ₃ ⁻ , C ₆ H ₁₃ OSO ₃ ⁻ , C ₈ H ₁₇ OSO 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 ⁻ , _{^{HF 2 -, (CN) 2}} N ^{_{, (CF 3 SO 2) (}} CF 3 CO) N -, (CH 3) 2 PO 4 -, (C 2 H 5) 2 PO 4 -, CH 3 (OC 2 H 4) 2 OSO 3 -, C 6 A metal salt composed of an anion composed of H ₄ (CH ₃ ) SO ₃ ⁻ , (C ₂ F ₅ ) ₃ PF ₃ ⁻ , CH ₃ CH (OH) COO ⁻ , and (FSO ₂ ) ₂ N ⁻ is preferable. Used for. More _{preferably, LiBr, LiI, LiBF 4,} LiPF 6, LiSCN, LiClO 4, LiCF 3 SO 3, Li (CF 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, Li (FSO 2 ) ₂ N, lithium salts such as Li (CF ₃ SO ₂ ) ₃ C, more preferably LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li ( C ₃ F ₇ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO ₂ ) ₂ N, Li (FSO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C are used. These alkali metal salts may be used alone or in combination of two or more.

  Further, by using the ionic liquid as an antistatic component (antistatic agent), an adhesive layer having a high antistatic effect can be obtained without impairing the adhesive properties. Although details of the reason why excellent antistatic properties can be obtained by using ionic liquids are not clear, ionic liquids have a low melting point (melting point of 100 ° C. or lower) compared to ordinary ionic compounds, so molecular movement is easy. It is considered that excellent antistatic ability can be obtained. In particular, when antistatic is applied to the adherend, it is considered that an excellent peeling antistatic property on the adherend can be achieved by transferring a very small amount of the ionic liquid to the adherend. In particular, since an ionic liquid having a melting point of room temperature (25 ° C.) or less can be transferred to an adherend more efficiently, excellent antistatic properties can be obtained.

  In addition, since the ionic liquid is liquid at a temperature of 100 ° C. or lower, it can be easily added and dispersed or dissolved in the pressure-sensitive adhesive as compared with a solid salt. Further, since the ionic liquid has no vapor pressure (nonvolatile), it has a characteristic that the antistatic property is continuously obtained without disappearing with time. The ionic liquid refers to a molten salt (ionic compound) having a melting point of 100 ° C. or lower and exhibiting a liquid state.

  As said ionic liquid, what consists of an organic cation component represented by the following general formula (A)-(E) and an anion component is used preferably. An ionic liquid having these cations provides a further excellent antistatic ability.

R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a hetero atom, and R _b and R _c May be the same or different and each represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom. However, when the nitrogen atom contains a double bond, there is no R _c .

R _d in the formula (B) represents a hydrocarbon group having 2 to 20 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a hetero atom, R _e , R _f And R _g may be the same or different and each represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom.

R _h in the formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a hetero atom, R _i , R _j , And R _k may be the same or different and each represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom.

Z in the formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁ , R _m , R _n , and R _o are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. In addition, a functional group in which a part of the hydrocarbon group is substituted with a hetero atom may be used. However, when Z is a sulfur atom, there is no _Ro .

R _P in the formula (E) represents a hydrocarbon group having 1 to 18 carbon atoms, a part of the hydrocarbon group may be substituted by a functional group with a heteroatom.

  Examples of the cation represented by the formula (A) include a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, and a morpholinium cation.

  Specific examples include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl. -3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidi Cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium Cation, 1-ethyl-1-propylpyrrolidini Cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium Cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation, pyrrolidinium-2-one cation, 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpi Peridinium cation, 1-methyl-1-pentylpiperidinium cation 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1 -Ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1-propyl -1-butylpiperidinium cation, 1,1-dibutylpiperidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole Cations, N-ethyl-N-methylmorpholinium cations, etc. It is done.

  Examples of the cation represented by the formula (B) include an imidazolium cation, a tetrahydropyrimidinium cation, and a dihydropyrimidinium cation.

  Specific examples include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, and 1-helium. Xyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazole Cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3 -Dimethylimidazolium cation, 1- (2-metho (Ciethyl) -3-methylimidazolium cation, 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium Cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium Cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium Cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium kathi Emissions, such as 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation.

  Examples of the cation represented by the formula (C) include a pyrazolium cation and a pyrazolinium cation.

  Specific examples include, for example, 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation, 1-ethyl-2,3,5-trimethylpyrazolium cation. 1-propyl-2,3,5-trimethylpyrazolium cation, 1-butyl-2,3,5-trimethylpyrazolium cation, 1-ethyl-2,3,5-trimethylpyrazolinium cation, 1 -Propyl-2,3,5-trimethylpyrazolinium cation, 1-butyl-2,3,5-trimethylpyrazolinium cation and the like.

  Examples of the cation represented by the formula (D) include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. And so on.

  Specific examples include, for example, tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutyl Ethylsulfonium Kachi , Dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, diallyldimethylammonium cation And tributyl- (2-methoxyethyl) phosphonium cation. Among them, asymmetric such as triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, etc. Tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N, N -Dimethyl-N-ethyl-N-propyla Monium cation, N, N-dimethyl-N-ethyl-N-butylammonium cation, N, N-dimethyl-N-ethyl-N-pentylammonium cation, N, N-dimethyl-N-ethyl-N-hexylammonium cation N, N-dimethyl-N-ethyl-N-heptylammonium cation, N, N-dimethyl-N-ethyl-N-nonylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N, N-diethyl-N-propyl-N-butylammonium cation, N, N-dimethyl-N-propyl-N-pentylammonium cation, N, N-dimethyl-N-propyl-N-hexylammonium cation, N, N- Dimethyl-N-propyl-N-heptylammonium cation, N, N-di Tyl-N-butyl-N-hexylammonium cation, N, N-diethyl-N-butyl-N-heptylammonium cation, N, N-dimethyl-N-pentyl-N-hexylammonium cation, N, N-dimethyl- N, N-dihexylammonium cation, trimethylheptylammonium cation, N, N-diethyl-N-methyl-N-propylammonium cation, N, N-diethyl-N-methyl-N-pentylammonium cation, N, N-diethyl -N-methyl-N-heptylammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylheptylammonium cation, N, N- Dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N-butyl-N-hexylammonium cation, N, N-dipropyl- N, N-dihexylammonium cation, N, N-dibutyl-N-methyl-N-pentylammonium cation, N, N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethylammonium cation, N-methyl- N-ethyl-N-propyl-N-pentylammonium cation is preferably used.

Examples of the cation represented by the formula (E) include a sulfonium cation. Further, the formula Specific examples of R _P in (E) is a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, An octadecyl group etc. are mentioned.

On the other hand, the anion component is not particularly limited as long as it satisfies that it becomes an ionic liquid. For example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH 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 ⁻ , HF ₂ ⁻ , (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 -, _{^{9 H 19 COO -, (CH}} 3) 2 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.

Moreover, as the anion component, an anion represented by the following formula (F) can also be used.

  As an anion component, an anion component containing a fluorine atom is particularly preferably used because an ionic liquid having a low melting point is obtained.

Specific examples of the ionic liquid used in the present invention are appropriately selected from a combination of the cation component and the anion component. For example, 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl -3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethane Sulfonyl) imide, 1-hexylpyridinium tetrafluoroborate, 1,1-dimethylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpyrrolidinium bis ( Trifluoromethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-pentyl Pyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1 -Ethyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-pentylpyrrolidinium bis (trifluorome Sulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1,1-dipropylpyrrole Dinium bis (triple olomethanesulfonyl) imide, 1-propyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1,1-dibutylpyrrolidinium bis (triple methanesulfonyl) imide, 1-propylpi Peridinium bis (trifluoromethanesulfonyl) imide, 1-pentylbiberidinium bis (trifluoromethanesulfonyl) imide, 1,1-dimethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpiperidi Niu Mubis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-butylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1- Pentylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-heptylpiperidinium bis (trifluoromethanesulfonyl) imide, 1 -Ethyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-butylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-pentylpiperidinium bis (trif Olomethanesulfonyl) imide, 1-ethyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-heptylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1-dipropyl Piperidinium bis (trifluoromethanesulfonyl) imide, 1-propyl-1-butylpiperidiniumpis (trifluoromethanesulfonyl) imide, 1,1-dibutylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1-dimethyl Pyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-ethylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (pentafluoroethanesulfonyl) imi 1-methyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-pentylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-hexylpyrrolidinium Bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-heptylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-propylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1- Ethyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-pentylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (penta Fluoroethanesulfonyl) imi 1-ethyl-1-heptylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dipropylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-propyl-1-butylpyrrolidinium Bis (pentafluoroethanesulfonyl) imide, 1,1-dibutylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-pentylpiperidinium bis (venta) Fluoroethanesulfonyl) imide, 1,1-dimethylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-ethylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-propylpi Peridinium (Pentafluoroethanesulfonyl) imide, 1-methyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl -1-hexylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-heptylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-propylpiperidinium bis (penta Fluoroethanesulfonyl) imide, 1-ethyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1- Hexyl piperidinium Bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-heptylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dipropylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-propyl -1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dibutylpiperidinium bis (pentafluoroethanesulfonyl) imide, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2- Phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium Acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazole 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl), 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide Imido, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexa Fluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3- Methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1- Hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl -3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium Bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium tetrafluoroborate, 2-methylpyrazolium tetrafluoroporate, 1-ethyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-2, 3,5-trimmer Tylpyrazolium bis (pentafluoroethanesulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazolium bis (pentafluoroethanesulfonyl) imide, 1-butyl-2,3,5-trimethylpyrazolium Bis (pentafluoroethanesulfonyl) imide, 1-ethyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) trifluoroacetamide, 1-propyl-2,3,5-trimethylpyrazolium bis (trifluoro) (Romethanesulfonyl) trifluoroacetamide, 1-butyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) ) Imide, -Propyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) imide, 1-butyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-2,3 , 5-trimethylpyrazolinium bis (pentafluoroethanesulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazolinium bis (pentafluoroethanesulfonyl) imide, 1-butyl-2,3,5-trimethyl Pyrazolinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) trifluoroacetamide, 1-propyl-2,3,5-trimethylpyrazolinium Bis (trifluoromethanesulfonyl) Trifluoroacetamide, 1-butyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) trifluoroacetamide, tetrapentylammonium trifluoromethanesulfonate, tetrapentylammonium bis (trifluoromethanesulfonyl) imide, tetrahexylammonium trifluoro Lomethanesulfonate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, tetrahebutylammonium trifluoromethanesulfonate, tetraheptylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium Screw Trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, N, N-diethyl-N- Methyl-N- (2
-Methoxyethyl) ammonium trifluoromethanesulfonate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-Nmethyl-N- (2- Methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, tetraoctylphosphonium trifluoromethanesulfonate, Tetraoctylphosphonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-propyl Propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-pentylammonium bis (trifluoro) Romethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-nonylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N -Propi Ru-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-hexylammonium Bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) Imide, N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, , N-dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) Imido, N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N- Diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, triethylpentylammonium vinyl (Trifluoromethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl-N-ethylammonium bis (trifluoromedansulfonyl) imide, N, N-dipropyl-N-methyl -N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N, N-dihexylammonium bis ( Trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-hexylammonium bis (t Trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, 1-butylpyridinium (trifluoromethane) Sulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N-ethyl-N-methylmorpholine Examples thereof include nium thiocyanate and 4-ethyl-4-methylmorpholinium methyl carbonate.

  A commercially available ionic liquid as described above may be used, but it can also be synthesized as follows. The method of synthesizing the ionic liquid is not particularly limited as long as the target ionic liquid can be obtained. In general, however, it is described in the document “Ionic liquids—the forefront and future of development” [CMC Publishing Co., Ltd.] As described, a halide method, a hydroxide method, an acid ester method, a complex formation method, a neutralization method, and the like are used.

  The synthesis method of the halide method, hydroxide method, acid ester method, complex formation method, and neutralization method will be described below using a nitrogen-containing onium salt as an example. Other sulfur-containing onium salts, phosphorus-containing onium salts, etc. This ionic liquid can also be obtained by the same method.

The halide method is a method carried out by reactions as shown in the following formulas (1) to (3). First, a tertiary amine and an alkyl halide are reacted to obtain a halide. (Reaction formula (1), chlorine, bromine and iodine are used as the halogen) Acid (HA) or salt (MA, M having the anionic structure (A ⁻ ) of the ionic liquid intended for the obtained halide A target ionic liquid (R ₄ NA) is obtained by reacting with a target anion such as ammonium, lithium, sodium, potassium and the like to form a salt.

The hydroxide method is a method performed by reactions as shown in (4) to (8). First, halide (R ₄ NX) is subjected to ion exchange membrane electrolysis (reaction formula (4)), OH type ion exchange resin method (reaction formula (5)) or reaction with silver oxide (Ag ₂ O) (reaction formula ( 6)) to obtain the hydroxide (R ₄ NOH). (Chlorine, bromine and iodine are used as the halogen) The obtained hydroxide is subjected to the reaction of the reaction formulas (7) to (8) in the same manner as the halogenation method, and the target ionic liquid (R ₄ NA ) Is obtained.

The acid ester method is a method performed by reactions as shown in (9) to (11). First, a tertiary amine (R ₃ N) is reacted with an acid ester to obtain an acid ester product. (Reaction formula (9), as the acid ester, an ester of an inorganic acid such as sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid or carbonic acid, or an organic acid such as methanesulfonic acid, methylphosphonic acid or formic acid) The target ionic liquid (R ₄ NA) is obtained from the obtained acid ester using the reactions of the reaction formulas (10) to (11) in the same manner as in the halogenation method. Further, by using methyl trifluoromethanesulfonate, methyl trifluoroacetate or the like as the acid ester, an ionic liquid can be obtained directly.

The complex formation method is a method performed by reactions as shown in (12) to (15). First, a quaternary ammonium halide (R ₄ NX), a quaternary ammonium hydroxide (R ₄ NOH), a quaternary ammonium carbonate ester (R ₄ NOCO ₂ CH ₃ ) or the like is added to hydrogen fluoride (HF) or Reaction with ammonium fluoride (NH ₄ F) gives a quaternary ammonium fluoride salt. (Reaction Formulas (12) to (14)) The obtained quaternary ammonium fluoride salt is complexed with fluorides such as BF ₃ , AlF ₃ , PF ₅ , AsF ₅ , SbF ₅ , NbF ₅ , TaF _5. An ionic liquid can be obtained. (Reaction Formula (15))

The neutralization method is a method performed by a reaction as shown in (16). Tertiary amine and HBF ₄ , HPF ₆ , CH ₃ COOH, CF ₃ COOH, CF ₃ SO ₃ H, (CF ₃ SO ₂ ) ₂ NH, (CF ₃ SO ₂ ) ₃ CH, (C ₂ F ₅ SO ₂ ) ₂ It can be obtained by reacting with an organic acid such as NH.

  R in the formulas (1) to (16) represents hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom. Good.

  In addition, the said ionic liquid may be used independently and may mix and use 2 or more types.

  Moreover, 1 mass part or less is preferable with respect to 100 mass parts of said (meth) acrylic-type polymers, 0.001-0.9 mass part is more preferable, More preferably, it is 0.00. 005 to 0.8 parts by mass, most preferably 0.01 to 0.5 parts by mass. It is preferable for it to be in the above-mentioned range since it is easy to achieve both antistatic properties and low contamination.

<Organopolysiloxane having an oxyalkylene chain>
In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains an organopolysiloxane having an oxyalkylene chain, and more preferably contains an organopolysiloxane having an oxyalkylene main chain. By using the organopolysiloxane, it is presumed that the surface free energy on the surface of the pressure-sensitive adhesive is reduced and light release is realized.

(式中、Ｒ_１及び／又はＲ_２は、炭素数１〜６のオキシアルキレン鎖を有し、前記オキシアルキレン鎖中のアルキレン基は、直鎖又は分岐していてもよく、前記オキシアルキレン鎖の末端が、アルコキシ基、又は、ヒドロキシル基であってもよい。また、Ｒ_１又はＲ_２のいずれか一方が、ヒドロキシル基でもよく、又は、アルキル基、アルコキシ基であってもよく、前記アルキル基、アルコキシ基の一部が、ヘテロ原子で置換された官能基であってもよい。ｎは、１〜３００の整数である。) As the organopolysiloxane, a known organopolysiloxane having a polyoxyalkylene main chain can be used as appropriate, and is preferably represented by the following formula.

(Wherein R ₁ and / or R ₂ has an oxyalkylene chain having 1 to 6 carbon atoms, and the alkylene group in the oxyalkylene chain may be linear or branched, and the oxyalkylene chain) The terminal of may be an alkoxy group or a hydroxyl group, and either R ₁ or R ₂ may be a hydroxyl group, or may be an alkyl group or an alkoxy group. A functional group in which a part of the group or alkoxy group is substituted with a hetero atom may be used, and n is an integer of 1 to 300.)

  The organopolysiloxane has a siloxane-containing site (siloxane site) as the main chain and an oxyalkylene chain bonded to the end of the main chain. By using the organosiloxane having an oxyalkylene chain, it is presumed that the compatibility of the (meth) acrylic polymer and the ionic compound is balanced and light release is realized.

Moreover, as said organopolysiloxane in this invention, the following structures can be used, for example. 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 as the oxyalkylene chain, an oxymethylene group, an oxyethylene group, an oxy Examples thereof include a propylene group and an oxybutylene group, and among them, an oxyethylene group and an oxypropylene group are preferable. In addition, when both R ₁ and R ₂ have an oxyalkylene chain, they may be the same or different.

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

  Furthermore, the end of the oxyalkylene chain may be an alkoxy group or a hydroxyl group, but more preferably an alkoxy group. When the separator is bonded to the surface of the adhesive layer for the purpose of protecting the adhesive surface, the organopolysiloxane having a hydroxyl group at the end causes an interaction with the separator, and adhesion (peeling) occurs when the separator is removed from the surface of the adhesive layer. The power may increase.

  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 and a preferred embodiment is obtained. Furthermore, you may have reactive substituents, such as a (meth) acryloyl group, an allyl group, and a hydroxyl group, in a molecule | numerator. The organopolysiloxane 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, KF-889. (Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (Toray Dow Corning, Inc.), IM22 (Asahi Kasei Wacker Co., Ltd.) and the like. These compounds may be used alone or in combination of two or more.

(式中、Ｒ_１は１価の有機基、Ｒ_２，Ｒ_３及びＲ_４はアルキレン基、Ｒ_５は水素もしくは有機基、ｍ及びｎは０〜１０００の整数。但し、ｍ, ｎが同時に０となることはない。ａ及びｂは０〜１００の整数。但し、ａ, ｂが同時に０となることはない。) In addition to the organosiloxane having (bonding) the oxyalkylene chain in the main chain, it is also possible to use an organosiloxane having (bonding) the oxyalkylene chain in the side chain. The use of an organosiloxane having an alkylene chain is a more preferred embodiment. As the organopolysiloxane, an organopolysiloxane having a known polyoxyalkylene side chain can be used as appropriate, 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, and m and n are integers from 0 to 1000, provided that m and n are simultaneously (A and b are integers from 0 to 100, provided that a and b are not 0 at the same time.)

Moreover, as said organopolysiloxane in this invention, the following structures can be used, for example. Specifically, R ₁ in the formula is a monovalent group exemplified by an alkyl group such as a methyl group, an ethyl group or a propyl group, an aryl group such as a phenyl group or a tolyl group, or an alkyl group such as a benzyl group or a phenethyl group. It is an organic group, and each may have a substituent such as a hydroxyl group. R ₂ , R ₃ and R ₄ may be an alkylene group having 1 to 8 carbon atoms such as a methylene group, an ethylene group or a propylene group. 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 an ionic compound that can be dissolved in the polyoxyalkylene side chain. R ₅ may be an alkyl group such as a methyl group, an ethyl group or a propyl group, or a monovalent organic group exemplified by an acyl group such as an acetyl group or a propionyl group, each having a substituent such as a hydroxyl group. It may be. These compounds may be used alone or in combination of two or more. Moreover, you may have reactive substituents, such as a (meth) acryloyl group, an allyl group, and a hydroxyl group, in a molecule | numerator. Among the organosiloxanes having a polyoxyalkylene side chain, an organosiloxane having a polyoxyalkylene side chain having a hydroxyl group terminal is presumed to have a good balance of compatibility.

  Specific examples of the organosiloxane include, for example, commercial names KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF. -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) 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 (above, manufactured by Toray Dow Corning), TSF-44 0, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4442, TSF-4460 (manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (manufactured by Big Chemie Japan) can be used. These compounds may be used alone or in combination of two or more.

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

  Moreover, 0.01-5 mass parts is preferable with respect to 100 mass parts of said (meth) acrylic-type polymers, More preferably, it is 0.03-3 mass parts, More preferably. Is 0.05 to 1 part by mass, most preferably 0.05 to 0.5 part by mass. It is preferable for it to be in the above-mentioned range since both antistatic properties and light releasability (removability) can be easily achieved.

<Crosslinking agent>
In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains a crosslinking agent. Moreover, in this invention, it is set as an adhesive layer using the said adhesive composition. For example, when the pressure-sensitive adhesive contains the (meth) acrylic polymer, the structural unit of the (meth) acrylic polymer, the structural ratio, the selection and addition ratio of the crosslinking agent, etc. are appropriately adjusted for crosslinking. Thus, 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 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. Moreover, these compounds may be used independently and may be used in mixture of 2 or more types.

  Examples of the isocyanate compound (isocyanate-based crosslinking agent) include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), dimer diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate. (IPDI), alicyclic isocyanates such as 1,3-bis (isocyanatomethyl) cyclohexane, aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate (XDI) , Allophanate bond, biuret bond, isocyanurate bond, uretdione bond, urea If, carbodiimide coupling, uretonimine bond, polyisocynate modified product obtained by modifying the like oxadiazinetrione bond. For example, as commercial products, the product names Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (above, manufactured by Takeda Pharmaceutical Company Limited), Sumijoule T80, Sumijoule L, Death Module N3400 (above, Sumika Bayer Urethane) Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. These isocyanate compounds may be used alone, or may be used in combination of two or more, and a bifunctional isocyanate compound and a trifunctional or higher isocyanate compound may be used in combination. By using a cross-linking agent in combination, it becomes possible to achieve both tackiness and resilience resistance (adhesiveness to a curved surface), and a surface protective film with better adhesion reliability can be obtained.

  The isocyanate compound (when a bifunctional isocyanate compound and a trifunctional or higher functional isocyanate compound are used in combination as the isocyanate crosslinking agent, the blending ratio (weight ratio) of both compounds is [bifunctional isocyanate]. Compound] / [Trifunctional or higher functional isocyanate compound] (weight ratio) is preferably 0.1 / 99.9 to 50/50, more preferably 0.1 / 99.9 to 20/80, 0.1 / 99.9 to 10/90 is more preferable, 0.1 / 99.9 to 5/95 is more preferable, and 0.1 / 99.9 to 1/99 is most preferable. Thus, it becomes a pressure-sensitive adhesive layer excellent in adhesiveness and repulsion resistance, and is a preferred embodiment.

  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-dioxy). Glycidylaminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.).

  Examples of the melamine resin include hexamethylol melamine. Examples of the aziridine derivative include commercially available product names HDU, TAZM, TAZO (manufactured by Mutual Yakugyo Co., Ltd.) and the like.

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

  The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 10 parts by mass, and 0.1 to 8 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer. It is more preferably contained, more preferably 0.5 to 5 parts by mass, and most preferably 1.0 to 2.5 parts by mass. When the content is less than 0.01 parts by mass, the crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the resulting pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained, It tends to cause glue residue. On the other hand, when the content exceeds 10 parts by mass, the cohesive force of the polymer is large, the fluidity is lowered, the wettability to the adherend (for example, polarizing plate) becomes insufficient, and the adherend and the pressure-sensitive adhesive. There is a tendency to cause blisters generated between the layer (adhesive composition layer). Furthermore, when the amount of the crosslinking agent is large, the peeling charging property tends to be lowered. These crosslinking agents may be used alone or in combination of two or more.

  The pressure-sensitive adhesive composition may further contain a cross-linking catalyst for causing any of the cross-linking reactions described above to proceed more effectively. Examples of such crosslinking catalysts include tin 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 (tridecan-6,8-dionato) iron, tris (1-phenylbutane-1,3) Diato) iron, tris (hexafluoroacetylacetonato) iron, tris (ethyl acetoacetate) iron, tris (acetoacetate-n-propyl) iron, tris (isopropyl acetoacetate) iron, tris (acetoacetate-n-butyl) Iron, tris (acetoacetate-sec-butyl) iron, tris (acetoacetate-tert-butyl) iron, tris (methyl propionylacetate) iron, tris (ethyl propionylacetate) iron, tris (propionylacetate-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, trimethoxy iron, Iron-based catalysts such as triethoxy iron, triisopropoxy iron, and ferric chloride can be used. These crosslinking catalysts may be used alone or in combination of two or more.

  The content (use amount) of the crosslinking catalyst is not particularly limited, but is preferably about 0.0001 to 1 part by mass with respect to 100 parts by mass of the (meth) acrylic polymer, for example, 0.001 -0.5 mass part is more preferable. Within the above range, when the pressure-sensitive adhesive layer is formed, the speed of the crosslinking reaction is high, and the pot life of the pressure-sensitive adhesive composition becomes long, which is a preferred embodiment.

  The pressure-sensitive adhesive composition may contain a polyoxyalkylene chain-containing compound that does not contain organopolysiloxane. By containing the said compound in an adhesive, the adhesive which was further excellent in the wettability to a to-be-adhered body can be obtained.

  Specific examples of the polyoxyalkylene chain-containing compound not containing the organopolysiloxane include, for example, polyoxyalkylene alkylamine, polyoxyalkylene diamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkylphenyl. Nonionic surfactants such as ether, polyoxyalkylene alkyl ether, polyoxyalkylene alkyl allyl ether, polyoxyalkylene alkyl phenyl allyl ether; polyoxyalkylene alkyl ether sulfate ester salt, polyoxyalkylene alkyl ether phosphate ester salt, Polyoxyalkylene alkyl phenyl ether sulfate ester salt, polyoxyalkylene alkyl phenyl ether phosphate ester Anionic surfactants such as tellurium salts; other cationic surfactants having polyoxyalkylene chains (polyalkylene oxide chains), amphoteric surfactants, polyether compounds having polyoxyalkylene chains (and derivatives thereof) And acrylic compounds having a polyoxyalkylene chain (and derivatives thereof) and the like. Moreover, you may mix | blend a polyoxyalkylene chain containing monomer with an acrylic polymer as a polyoxyalkylene chain containing compound. Such polyoxyalkylene chain-containing compounds may be used alone or in combination of two or more.

  Specific examples of the polyether compound having a polyoxyalkylene chain include polypropylene glycol (PPG) -polyethylene glycol (PEG) block copolymer, PPG-PEG-PPG block copolymer, and PEG-PPG-PEG. Examples thereof include block copolymers. Examples of the derivative of the polyether compound having a polyoxyalkylene chain include an oxypropylene group-containing compound whose end is etherified (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.), an oxypropylene group whose end is acetylated Containing compounds (terminal acetylated PPG and the like), and the like.

  Specific examples of the acrylic compound having a polyoxyalkylene chain include a (meth) acrylate polymer having an oxyalkylene group. As said oxyalkylene group, 1-50 are preferable from a viewpoint that an ionic compound coordinates, and 2-30 are more preferable, and 2-20 are more preferable for the addition mole number of an oxyalkylene unit. The terminal of the oxyalkylene chain may be a hydroxyl group, or may be substituted with an alkyl group, a phenyl group or the like.

  The (meth) acrylate polymer having an oxyalkylene group is preferably a polymer containing an alkylene oxide (meth) acrylate as a monomer unit (component). Specific examples of the (meth) acrylate alkylene oxide Examples of the ethylene glycol group-containing (meth) acrylate include methoxy-polyethylene glycol (meth) acrylate types such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol ( Ethoxy-polyethylene glycol (meth) acrylate type such as meth) acrylate, ethoxy-triethylene glycol (meth) acrylate, butoxy-diethylene glycol (meth) acrylate, Butoxy-polyethylene glycol (meth) acrylate type such as xy-triethylene glycol (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate type such as phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate, Examples include 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate type, and methoxy-polypropylene glycol (meth) acrylate type such as methoxy-dipropylene glycol (meth) acrylate.

  Moreover, other monomer units (components) other than the (meth) acrylic acid alkylene oxide can also be used as the monomer units (components). Specific examples of other monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 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) ) Acrylates, isodecyl (meth) acrylates, n-dodecyl (meth) acrylates, n-tridecyl (meth) acrylates, n-tetradecyl (meth) acrylates and other acrylates and / or methacrylates having 1 to 14 carbon atoms And the like.

  Further, as other monomer units (components) other than the (meth) acrylic acid alkylene oxide, carboxyl group-containing (meth) acrylate, phosphoric acid group-containing (meth) acrylate, cyano group-containing (meth) acrylate, vinyl esters , Aromatic vinyl compound, acid anhydride group-containing (meth) acrylate, hydroxyl group-containing (meth) acrylate, amide group-containing (meth) acrylate, amino group-containing (meth) acrylate, epoxy group-containing (meth) acrylate, N- Acryloylmorpholine, vinyl ethers, and the like can be used as appropriate.

  As a more preferred embodiment, the polyoxyalkylene chain-containing compound not containing the organopolysiloxane is a compound having a (poly) ethylene oxide chain at least partially. By blending the (poly) ethylene oxide chain-containing compound, the compatibility between the base polymer and the antistatic component is improved, bleeding to the adherend is suitably suppressed, and a low-staining adhesive composition is obtained. It is done. In particular, when a PPG-PEG-PPG block copolymer is used, a pressure-sensitive adhesive excellent in low contamination can be obtained. As said polyethylene oxide chain containing compound, it is preferable that the weight of the (poly) ethylene oxide chain to the whole polyoxyalkylene chain containing compound which does not contain the said organopolysiloxane is 5-90 mass%, More preferably, it is 5-85. % By mass, more preferably 5 to 80% by mass, most preferably 5 to 75% by mass.

  The molecular weight of the polyoxyalkylene chain-containing compound not containing the organopolysiloxane is suitably a number average molecular weight (Mn) of 50000 or less, preferably 200-30000, more preferably 200-10000, 200 to 5000 are preferably used. When Mn is larger than 50000, the compatibility with the acrylic polymer is lowered and the pressure-sensitive adhesive layer tends to be whitened. If Mn is less than 200, contamination with the polyoxyalkylene compound may easily occur. In addition, Mn means the value of polystyrene conversion obtained by GPC (gel permeation chromatography) here.

  Specific examples of commercially available polyoxyalkylene chain-containing compounds that do not contain the organopolysiloxane include, for example, Adekapluronic 17R-4, Adekapluronic 25R-2 (all of which are manufactured by ADEKA), Emulgen 120 ( And Kao).

  As a compounding quantity of the polyoxyalkylene chain containing compound which does not contain the said organopolysiloxane, it can be set as 0.005-20 mass parts with respect to 100 mass parts of acrylic polymers, Preferably it is 0.01-10. Part by mass, more preferably 0.05 to 5 parts by mass, most preferably 0.1 to 1 part by mass. If the blending amount is too small, the effect of preventing bleeding of the antistatic component is reduced, and if it is too much, contamination by the polyoxyalkylene compound may easily occur.

Furthermore, the pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer preferably has a weight average molecular weight of 1000 or more and less than 30000, more preferably 1500 or more and less than 20000, and still more preferably 2000 or more and less than 10,000. The acrylic oligomer is a (meth) acrylic polymer containing a (meth) acrylic monomer having an alicyclic structure represented by the following general formula (17) as a monomer unit, and is used as an acrylic pressure-sensitive adhesive. In the case, it functions as a tackifier resin, improves the adhesion, and is effective in suppressing the float of the surface protective film.
CH ₂ = C (R ¹ ) COOR ² (17)
[In Formula (17), R ¹ is a hydrogen atom or a methyl group, and R ² is an alicyclic hydrocarbon group having an alicyclic structure]

Examples of the alicyclic hydrocarbon group R ² in the general formula (17) include alicyclic hydrocarbon groups such as a cyclohexyl group, an isobornyl group, and a dicyclopentanyl group. Examples of the (meth) acrylic acid ester having such an alicyclic hydrocarbon group include cyclohexyl (meth) acrylate having a cyclohexyl group, isobornyl (meth) acrylate having an isobornyl group, and a dicyclopentanyl group. Mention may be made of esters of (meth) acrylic acid with alicyclic alcohols such as (meth) acrylic acid dicyclopentanyl. Adhesiveness can be improved by giving an acrylic oligomer as a monomer unit an acrylic monomer having a relatively bulky structure.

  Furthermore, in this embodiment, it is preferable that the alicyclic hydrocarbon group which comprises the said acrylic oligomer has a bridged ring structure. The bridged ring structure refers to an alicyclic structure having three or more rings. By giving the acrylic oligomer a more bulky structure such as a bridged ring structure, it is possible to further improve the adhesiveness of the re-peeling acrylic pressure-sensitive adhesive composition (re-peeling acrylic surface protective film).

Examples of R ² that is an alicyclic hydrocarbon group having a bridged ring structure include a dicyclopentanyl group represented by the following formula (3a) and a dicyclopentenyl group represented by the following formula (3b). And adamantyl group represented by the following formula (3c), tricyclopentanyl group represented by the following formula (3d), tricyclopentenyl group represented by the following formula (3e), and the like. In addition, when UV polymerization is employed in the synthesis of an acrylic oligomer or in the preparation of a pressure-sensitive adhesive composition, an alicyclic structure having three or more rings having a bridged ring structure is used because it is difficult to cause polymerization inhibition. Among the (meth) acrylic monomers possessed, in particular, a dicyclopentanyl group represented by the following formula (3a), an adamantyl group represented by the following formula (3c), and a trimethyl group represented by the following formula (3d) A (meth) acrylic monomer having a saturated structure such as a cyclopentanyl group can be suitably used as a monomer constituting the acrylic oligomer.

  Examples of the (meth) acrylic monomer having a tricyclic or higher alicyclic structure having a bridged ring structure include dicyclopentanyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyloxyethyl methacrylate, Dicyclopentanyloxyethyl acrylate, tricyclopentanyl methacrylate, tricyclopentanyl acrylate, 1-adamantyl methacrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-methyl-2-adamantyl acrylate, 2- Mention may be made of (meth) acrylic acid esters such as ethyl-2-adamantyl methacrylate and 2-ethyl-2-adamantyl acrylate. These (meth) acrylic monomers can be used alone or in combination of two or more.

  The acrylic oligomer of this embodiment may be a homopolymer of a (meth) acrylic monomer having an alicyclic structure, or a (meth) acrylic monomer having an alicyclic structure and another (meth) acrylic. It may be a copolymer with an acid ester monomer or a copolymerizable monomer.

Examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth ) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid 2-ethylhexyl, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic Of isodecyl acid, undecyl (meth) acrylate, dodecyl (meth) acrylate Una (meth) acrylic acid alkyl ester;
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate;
And (meth) acrylic acid esters obtained from terpene compound derivative alcohols. Such (meth) acrylic acid esters can be used alone or in combination of two or more.

  In addition to the (meth) acrylic acid ester component unit, the acrylic oligomer can be obtained by copolymerizing another monomer component (copolymerizable monomer) copolymerizable with (meth) acrylic acid ester. It is.

Other monomers copolymerizable with the (meth) acrylic acid ester include carboxyl groups such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Containing monomers;
Alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate monomer;
(Meth) acrylic acid alkali metal salts and the like;
Di (meth) acrylic acid ester of ethylene glycol, di (meth) acrylic acid ester of diethylene glycol, di (meth) acrylic acid ester of triethylene glycol, di (meth) acrylic acid ester of polyethylene glycol, di (meta) of propylene glycol ) Di (meth) acrylate monomers of (poly) alkylene glycols such as acrylate esters, di (meth) acrylate esters of dipropylene glycol, di (meth) acrylate esters of tripropylene glycol;
Polyvalent (meth) acrylate monomers such as trimethylolpropane tri (meth) acrylate;
Vinyl esters such as vinyl acetate and vinyl propionate;
Vinyl halide compounds such as vinylidene chloride and 2-chloroethyl (meth) acrylate;
An oxazoline group-containing polymerizable compound such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline;
Aziridine group-containing polymerizable compounds such as (meth) acryloylaziridine, (meth) acrylic acid-2-aziridinylethyl;
Epoxy group-containing vinyl monomers such as allyl glycidyl ether, (meth) acrylic acid glycidyl ether, (meth) acrylic acid-2-ethylglycidyl ether;
Hydroxyl group-containing vinyl monomers such as (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, adducts of lactones and (meth) acrylic acid-2-hydroxyethyl;
(Meth) acryloyl group at the end of polyalkylene glycol such as polypropylene glycol, polyethylene glycol, polytetramethylene glycol, polybutylene glycol, copolymer of polyethylene glycol and polypropylene glycol, copolymer of polybutylene glycol and polyethylene glycol, A macromonomer to which an unsaturated group such as a styryl group or a vinyl group is bonded;
Fluorine-containing vinyl monomers such as fluorine-substituted (meth) acrylic acid alkyl esters;
Acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride;
Aromatic vinyl compound monomers such as styrene, α-methylstyrene, vinyltoluene;
Reactive halogen-containing vinyl monomers such as 2-chloroethyl vinyl ether and monochloro vinyl acetate;
(Meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N An amide group-containing vinyl monomer such as ethylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-acryloylmorpholine;
Succinimide monomers such as N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- (meth) acryloyl-8-oxyhexamethylenesuccinimide;
Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide;
Itaconimides such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide System monomers;
N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N- Vinyloxazole, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N-vinylmorpholine, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole Nitrogen-containing heterocyclic monomers such as N-vinylisothiazole and N-vinylpyridazine;
N-vinylcarboxylic acid amides;
Lactam monomers such as N-vinylcaprolactam;
Cyanoacrylate monomers such as (meth) acrylonitrile;
(Meth) acrylic such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate Acid aminoalkyl monomers;
Imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide;
Isocyanate group-containing monomers such as 2-isocyanatoethyl (meth) acrylate;
Organosilicon-containing vinyl monomers such as vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, 2-methoxyethoxytrimethoxysilane;
Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxydecyl (meth) acrylate, (meta ) Hydroxyl-containing monomers such as hydroxyalkyl (meth) acrylates such as hydroxylauryl acrylate and (4-hydroxymethylcyclohexyl) methyl methacrylate;
(Meth) acrylic acid tetrahydrofurfuryl, fluorine atom-containing (meth) acrylate, silicone (meth) acrylate and other heterocyclic rings, halogen atoms, silicon atoms and the like, acrylic ester monomers;
Olefin monomers such as isoprene, butadiene, isobutylene;
Vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether;
Olefins or dienes such as ethylene, butadiene, isoprene, isobutylene;
Vinyl ethers such as vinyl alkyl ethers;
Vinyl chloride;
Other examples include macromonomers having a radical polymerizable vinyl group at the terminal of a monomer obtained by polymerizing a vinyl group. These monomers can be copolymerized with the (meth) acrylic acid ester alone or in combination.

  Examples of the acrylic oligomer include a copolymer of cyclohexyl methacrylate (CHMA) and isobutyl methacrylate (IBMA), a copolymer of cyclohexyl methacrylate (CHMA) and isobornyl methacrylate (IBXMA), methyl methacrylate (MMA) and isobornol. Nyl methacrylate (IBXMA) copolymer, cyclohexyl methacrylate (CHMA) and acryloylmorpholine (ACMO) copolymer, cyclohexyl methacrylate (CHMA) and diethyl acrylamide (DEAA) copolymer, 1-adamantyl acrylate (ADA) and Copolymer of methyl methacrylate (MMA), copolymer of dicyclopentanyl methacrylate (DCPMA) and isobornyl methacrylate (IBXMA) Copolymer of dicyclopentanyl methacrylate (DCPMA) and methyl methacrylate (MMA), copolymer of dicyclopentanyl methacrylate (DCPMA) and N-vinyl-2-pyrrolidone (NVP), dicyclopentanyl methacrylate (DCPMA) ) And hydroxyethyl methacrylate (HEMA), dicyclopentanyl methacrylate (DCPMA) and acrylic acid (AA), dicyclopentanyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl Methacrylate (IBXMA), isobornyl acrylate (IBXA), dicyclopentanyl acrylate (DCPA), 1-adamantyl methacrylate (ADMA), 1-adamantyl acrylate (ADA), Each homopolymers such chill methacrylate (MMA) can be exemplified.

  Furthermore, the acrylic oligomer may have a functional group having reactivity with an epoxy group or an isocyanate group. Examples of such functional groups include a hydroxyl group, a carboxyl group, an amino group, an amide group, and a mercapto group. When an acrylic oligomer is produced, a monomer having such a functional group is used (copolymerized). Also good.

  When the acrylic oligomer is a copolymer of a (meth) acrylic monomer having an alicyclic structure and another (meth) acrylic acid ester monomer or a copolymerizable monomer, it has an alicyclic structure (meth) The content of the acrylic monomer is preferably 5% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more in the total monomers constituting the acrylic oligomer (usually normal). Less than 100% by mass, preferably 90% by mass or less). If 5 mass% or more of the (meth) acrylic-type monomer which has an alicyclic structure is contained, adhesiveness can be improved, without reducing transparency.

  The acrylic oligomer has a weight average molecular weight of 1000 or more and less than 30000, preferably 1500 or more and less than 20000, and more preferably 2000 or more and less than 10,000. Adhesiveness falls that a weight average molecular weight is 30000 or more. On the other hand, if the weight average molecular weight is less than 1000, the molecular weight becomes low, which causes a decrease in the adhesive strength of the surface protective film.

  As a compounding quantity of the said acrylic oligomer, it is preferable that 0.01-10 mass parts is contained with respect to 100 mass parts of said (meth) acrylic-type polymers, and 0.1-7 mass parts is contained. Is more preferably 0.2 to 5 parts by mass, and most preferably 0.3 to 2 parts by mass. By using the blending amount in the above range, it is possible to improve the adhesive force to the adherend, and to easily suppress the float, which is a preferable mode.

  Furthermore, the pressure-sensitive adhesive composition may contain other known additives, such as powders such as colorants and pigments, surfactants, plasticizers, tackifiers, low molecular weight polymers, Surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, UV absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils, etc. Can be added as appropriate according to the intended use.

<Adhesive layer / surface protective film>
The surface protective film of the present invention is formed by forming the pressure-sensitive adhesive layer on a substrate. In this case, the pressure-sensitive adhesive composition is generally crosslinked after the pressure-sensitive adhesive composition is applied. However, it is also possible to transfer the pressure-sensitive adhesive layer comprising the crosslinked pressure-sensitive adhesive composition to a substrate or the like.

  The method for forming the pressure-sensitive adhesive layer on the base material is not particularly limited. For example, the pressure-sensitive adhesive layer is applied to the base material by applying the pressure-sensitive adhesive composition (solution) to the base material and drying and removing the polymerization solvent. It is produced by forming on top. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. Moreover, when producing a surface protective film by applying the pressure-sensitive adhesive composition on the substrate, one or more solvents other than the polymerization solvent are added to the pressure-sensitive adhesive composition so that the surface-protective film can be uniformly applied on the substrate. You may add a new one.

  Moreover, as a formation method of the adhesive layer at the time of manufacturing the surface protection film of this invention, the well-known method used for manufacture of adhesive tapes is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

  The surface protective film of the present invention is usually produced so that the pressure-sensitive adhesive layer has a thickness of 3 to 100 μm, preferably about 5 to 50 μm. It is preferable for the thickness of the pressure-sensitive adhesive layer to be within the above range because it is easy to obtain an appropriate balance between removability and adhesiveness.

  In addition, the surface protective film of the present invention preferably has a total thickness of 1 to 400 μm, more preferably 10 to 200 μm, and most preferably 20 to 100 μm. Within the above range, the adhesive properties (removability, adhesiveness, etc.), workability, and appearance properties are excellent and a preferred embodiment is obtained. In addition, the said total thickness means the sum total of the thickness containing all layers, such as a base material, an adhesive layer, and an antistatic layer.

<Separator>
In the surface protective film of the present invention, a separator can be bonded to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface as necessary.

  Examples of the material constituting the separator include paper and plastic film, and a plastic film is preferably used from the viewpoint of excellent surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer Examples thereof 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 since it is excellent in workability for bonding to the pressure-sensitive adhesive layer and workability for peeling from the pressure-sensitive adhesive layer. For the separator, if necessary, mold release and antifouling treatment with a silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, silica powder, etc., coating type, kneading type, vapor deposition type It is also possible to carry out antistatic treatment such as.

  The optical member of the present invention is preferably protected by the surface protective film. Since the surface protective film is excellent in antistatic properties and stability over time of the peeling band voltage, it can be used for surface protection applications (surface protective film) during processing, transportation, shipment, etc. Therefore, the optical member (polarizing plate, etc.) It is useful for protecting the surface of the film. In particular, since it can be used for plastic products and the like that are likely to generate static electricity, it is very useful for antistatic applications in the technical fields related to optical and electronic parts where charging is a particularly serious problem.

  Hereinafter, several examples related to the present invention will be described, but the present invention is not intended to be limited to those shown in the specific examples. In the following description, “part” and “%” are based on mass unless otherwise specified. Further, the blending amount (addition amount) in the table indicates the solid content or the solid content ratio.

  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) was measured using a GPC apparatus (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.

Sample concentration: 0.2% by mass (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.

<Glass transition temperature (Tg)>
The glass transition temperature Tg (° C.) was determined by the following formula (18) using the following literature value as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.

Formula (18): 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)] [wherein 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. ] Literature values:
2-ethylhexyl acrylate (2EHA): -70 ° C
4-hydroxybutyl acrylate (4HBA): -32 ° C
2-Hydroxyethyl acrylate (HEA): -15 ° C
Acrylic acid (AA): 106 ° C

  As reference values, “Synthesis / design of acrylic resin and development of new applications” (published by Central Management Development Center Publishing Department) and “Polymer Handbook” (John Wiley & Sons) were referred.

<Measurement of surface resistance value>
Measurement was performed in accordance with JIS-K-6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analytic, Hiresta UP MCP-HT450 type) in an atmosphere of temperature 23 ° C. and humidity 50% RH.
The surface resistance value (Ω / □) in the present invention is preferably less than 1.0 × 10 ¹¹ both at the initial stage and at room temperature (23 ° C. × 50% RH) × 1 week (7 days). More preferably, it is less than 5.0 × 10 ¹⁰ , and further preferably less than 1.0 × 10 ¹⁰ . A surface protective film exhibiting a surface resistance value within the above range can be suitably used as a surface protective film used in the processing or transporting of articles that dislike static electricity such as liquid crystal cells and semiconductor devices.

<Measurement of polarizing plate peeling voltage (polarizing plate side)>
After the surface protective film 1 according to each example was cut to a size of 70 mm in width and 130 mm in length and the release liner was peeled off, as shown in FIG. 2, the acrylic plate 10 (Mitsubishi Rayon Co., Ltd. On the surface of the polarizing plate 20 (manufactured by Nitto Denko Corporation, SEG1423DU polarizing plate, width: 70 mm, length: 100 mm) bonded to the product name “Acrylite”, thickness: 1 mm, width: 70 mm, length: 100 mm, The surface protective film 1 was pressure-bonded with a hand roller so that one end of the surface protective film 1 protruded 30 mm from the end of the polarizing plate 20.
The 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 base 30 having a height of 20 mm. The end of the surface protective film 1 that protruded 30 mm from the polarizing plate 20 was fixed to an automatic winder (not shown), and was peeled so that the peeling angle was 150 ° and the peeling speed was 10 m / min. The potential measuring device 40 (model “KSD-0103” manufactured by Kasuga Denki Co., Ltd.) in which the potential of the adherend (polarizing plate) surface generated at this time is fixed at a position 100 mm in height from the center of the polarizing plate 20. The “initial polarizing plate stripping voltage” was measured. The measurement was performed in an environment of 23 ° C. and 50% RH.
Further, after being allowed to stand for 7 days in an environment of 23 ° C. × 50% RH, the “polarizing plate peeling band voltage with time” was measured in the same manner as the “initial polarizing plate peeling band voltage”. The measurement was performed in an environment of 23 ° C. × 50% RH.
The polarizing plate peeling voltage is a peeling voltage derived from the antistatic layer and the pressure-sensitive adhesive layer constituting the surface protective film of the present invention, and contributes to antistatic properties.
The polarizing plate peeling voltage (kV) (both absolute value, initial and time) in the present invention is preferably 0.8 or less, more preferably 0.7 or less, and still more preferably 0.8. 5 or less. Within the above range, for example, damage to a liquid crystal driver or the like can be prevented, which is a preferable mode.

<Measurement of film side peeling voltage (antistatic layer side of surface protective film)>
In the same manner as the measurement of the polarizing plate peeling voltage, the surface protective film 1 was peeled from the surface of the polarizing plate 20 so that the peeling angle was 150 ° and the peeling speed was 10 m / min. The potential of the surface protective film 1 generated at this time is measured by a potential measuring device 40 (model “KSD-0103” manufactured by Kasuga Denki Co., Ltd.), which is fixed at a height of 100 mm from the center of the surface protective film 1. “Initial film side peeling voltage” was measured. The measurement was performed in an environment of 23 ° C. and 50% RH.
Further, after being allowed to stand for 7 days in an environment of 23 ° C. × 50% RH, the “polarizing plate peeling band voltage with time” was measured in the same manner as the “initial polarizing plate peeling band voltage”. The measurement was performed in an environment of 23 ° C. × 50% RH.
In addition, a film side peeling voltage is a peeling voltage derived from the antistatic layer which comprises the surface protection film of this invention, and contributes to antistatic property.
The film side peeling voltage (kV) in the present invention (absolute value, both initial and time) is preferably 0.8 or less, more preferably 0.7 or less, and still more preferably 0. 5 or less. Within the above range, the surface protective film after peeling is not charged and is excellent in workability.

<Measurement of slipperiness (dynamic frictional force)>
The surface protective film is cut to a size of 70 mm in width and 100 mm in length, and is bonded to an acrylic plate (trade name “Acrylite”, manufactured by Mitsubishi Rayon Co., Ltd., thickness: 1 mm, width: 70 mm, length: 100 mm). Prepared. This test piece was placed on a smooth PET film held horizontally with the back surface (antistatic layer surface) facing down, and a load of 1.5 kg was placed on the test piece. The test piece loaded with the load was attached to a tensile tester using a non-stretchable thread, and the test piece was pulled horizontally at a measurement temperature of 25 ° C. under a tensile speed of 300 mm / min and a tensile distance of 300 mm. The average value (n = 3) of the dynamic friction force (N) was determined.
In addition, as slipperiness (dynamic frictional force) (N) in this invention, Preferably it is 5 or less, More preferably, it is 4.5 or less, More preferably, it is 4 or less. Within the above range, when handling the adherend to which the surface protective film is attached, it is advantageous in terms of workability that the sliding property of the back surface of the base material (surface of the antistatic layer) is good.

<Evaluation of printability (print adhesion)>
After printing on the surface of the antistatic layer using an X stamper manufactured by Shachihata Co., Ltd. in a measurement environment of 23 ° C. × 50% RH, a Nichiban cello tape (registered trademark) was applied on the printed surface. Next, peeling is performed under conditions of a peeling speed of 30 m / min and a peeling angle of 180 °. Then, the surface after peeling was visually observed, and x (printability failure) when 50% or more of the print area was peeled off, and ○ (good printability) when 50% or more of the print area remained without peeling. ).

<Preparation of acrylic polymer (I) for pressure-sensitive adhesive layer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of 4-hydroxybutyl acrylate (4HBA), acrylic acid (AA) 0.02 parts by mass, 0.22 parts by mass of 2,2′-azobisisobutyronitrile and 157 parts by mass of ethyl acetate as a polymerization initiator were charged, nitrogen gas was introduced while gently stirring, and the liquid in the flask A polymerization reaction was carried out for 6 hours while maintaining the temperature at around 65 ° C. to prepare an acrylic polymer (I) solution (40% by mass). The acrylic polymer (I) had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of −67 ° C.

<Preparation of acrylic polymer (II) for adhesive layer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by mass of 2-ethylhexyl acrylate (2EHA), 4 parts by mass of 2-hydroxyethyl acrylate (HEA), 2 as a polymerization initiator , 2'-azobisisobutyronitrile and 157 parts by weight of ethyl acetate were charged, nitrogen gas was introduced while gently stirring, and the temperature in the flask was kept at around 65 ° C for 6 hours of polymerization. Reaction was performed and the acrylic polymer (II) solution (40 mass%) was prepared. The acrylic polymer (II) had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of −68 ° C.

<Preparation of acrylic polymer (III) for pressure-sensitive adhesive layer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of 4-hydroxybutyl acrylate (4HBA), acrylic acid (AA) 0.05 parts by mass, 0.22 parts by mass of 2,2′-azobisisobutyronitrile and 157 parts by mass of ethyl acetate as a polymerization initiator were charged, nitrogen gas was introduced while gently stirring, and the liquid in the flask The polymerization reaction was carried out for 6 hours while maintaining the temperature at around 65 ° C. to prepare an acrylic polymer (III) solution (40% by mass). The acrylic polymer (III) had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of −67 ° C.

<Preparation of acrylic polymer (IV) for pressure-sensitive adhesive layer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of 4-hydroxybutyl acrylate (4HBA), acrylic acid (AA) 0.1 part by mass, 0.22 part by mass of 2,2′-azobisisobutyronitrile and 157 parts by mass of ethyl acetate as a polymerization initiator were charged, nitrogen gas was introduced while gently stirring, and the liquid in the flask A polymerization reaction was carried out for 6 hours while maintaining the temperature at around 65 ° C. to prepare an acrylic polymer (IV) solution (40% by mass). The acrylic polymer (IV) had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of −67 ° C.

[Preparation of acrylic oligomer]
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, cooler, and dropping funnel, 100 parts by mass of toluene, dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, Hitachi Chemical Co., Ltd.) 60 parts by mass), 40 parts by mass of methyl methacrylate (MMA), and 3.5 parts by mass of methyl thioglycolate as a chain transfer agent were added. Then, after stirring for 1 hour at 70 ° C. in a nitrogen atmosphere, 0.2 part by weight of 2,2′-azobisisobutyronitrile was added as a polymerization initiator, and the reaction was performed at 70 ° C. for 2 hours. After making it react at 80 degreeC for 4 hours, it was made to react at 90 degreeC for 1 hour, and the acrylic oligomer solution (51 mass%) was obtained. The acrylic oligomer had a weight average molecular weight of 4000 and a glass transition temperature (Tg) of 144 ° C.

[Preparation of acrylic pressure-sensitive adhesive solution (A)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the isocyanurate of hexamethylene diisocyanate (as a crosslinking agent) is added to 500 parts by mass of this solution (solid content: 100 parts by mass). Nippon Polyurethane Industry Co., Ltd., Coronate HX) 3.5 parts by mass (solid content 3.5 parts by mass), 3 parts by mass of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst (solid content 0.03 parts by mass) Was added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (A).

[Preparation of acrylic adhesive solution (B)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-353, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass (100 parts by mass of the solid content) of this solution. 2 parts by weight of a solution obtained by diluting the product with ethyl acetate to 10% (solid content: 0.2 parts by weight), as an alkali metal salt as an antistatic agent, lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO ₂ ) ₂ : LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate 15 parts by weight (solid content 0.15 parts by weight), hexamethylene diisocyanate isocyanurate (Japan Polyurethane Industry Co., Ltd.) as a crosslinking agent Manufactured by Coronate HX) 3.5 parts by mass (solid content 3.5 parts by mass), 3 parts by mass of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst ( 0.03 parts by mass of solid content) was added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (B).

[Preparation of acrylic pressure-sensitive adhesive solution (C)]
The acrylic polymer (II) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the isocyanurate of hexamethylene diisocyanate (as a crosslinking agent) is added to 500 parts by mass (100 parts by mass of solid content) of this solution. Nippon Polyurethane Industry Co., Ltd., Coronate HX) 3.5 parts by mass (solid content 3.5 parts by mass), 3 parts by mass of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst (solid content 0.03 parts by mass) Was added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (C).

[Preparation of acrylic adhesive solution (D)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-353, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass (100 parts by mass of the solid content) of this solution. 2 parts by weight (solid content 0.2 parts by weight) diluted with ethyl acetate to 10%, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) as an ionic liquid as an antistatic agent 15 parts by mass of imide (EMITFSI, manufactured by Tokyo Chemical Industry Co., Ltd.) diluted with ethyl acetate to 1% (solid content 0.15 parts by mass), hexamethylene diisocyanate isocyanurate (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent , Coronate HX) 2 parts by mass (solid content 2 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (Mitsui Chemicals, Takene) 600) 0.3 parts by mass (solid content 0.3 parts by mass) and 3 parts by mass (solid content 0.03 parts by mass) of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst were mixed and stirred. The acrylic pressure-sensitive adhesive solution (D) was prepared.

[Preparation of acrylic adhesive solution (E)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-353, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass (100 parts by mass of the solid content) of this solution. 1) ethyl acetate diluted to 10% with ethyl acetate 2 parts by weight (solid content 0.2 parts by weight), 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide as an ionic liquid as an antistatic agent 15 parts by mass (EMISSI, Daiichi Kogyo Seiyaku Co., Ltd.) diluted to 1% with ethyl acetate (0.15 parts by mass of solid content), hexamethylene diisocyanate isocyanurate (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent Coronate HX) 2 parts by mass (solid content 2 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (Mitsui Chemicals, Takenate 600) .3 parts by mass (solid content: 0.3 parts by mass) and 3 parts by mass (solid content: 0.03 parts by mass) of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a cross-linking catalyst were mixed and stirred. A system pressure-sensitive adhesive solution (E) was prepared.

[Preparation of acrylic adhesive solution (F)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-353, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass (100 parts by mass of the solid content) of this solution. 2 parts by mass (0.2 mass parts solids) diluted with ethyl acetate to 10%, 1-ethyl-3-methylimidazolium trifluoromethanesulfonic acid (EMIFSS) as an ionic liquid as an antistatic agent 15 parts by mass (made by Daiichi Kogyo Seiyaku Co., Ltd.) diluted to 1% with ethyl acetate (solid content 0.15 parts by mass), as a cross-linking agent, isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate) HX) 2 parts by mass (solid content 2 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (Mitsui Chemicals, Takenate 600) Add 3 parts by weight (solid content 0.3 parts by weight) and 3 parts by weight dibutyltin dilaurate (1% by weight ethyl acetate solution) (solid content 0.03 parts by weight) as a crosslinking catalyst. An agent solution (F) was prepared.

[Preparation of acrylic adhesive solution (G)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-6004, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass of this solution (solid content: 100 parts by mass). 20 parts by mass (solid content 0.2 parts by mass) diluted with ethyl acetate to 1%, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide as an ionic liquid as an antistatic agent 15 parts by mass (BMPTFSI, manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate (solid content 0.15 parts by mass), trimethylolpropane / tolylene diisocyanate trimer adduct (as a crosslinking agent) Nippon Polyurethane Industry Co., Ltd., Coronate L) 3 parts by mass (solid content 3 parts by mass), dibutyltin dilaurate (1% by mass ethyl acetate solution) 3 as a crosslinking catalyst Added amount (the solid part 0.03 part by weight), and mixed and stirred to prepare an acrylic adhesive solution (G).

[Preparation of acrylic adhesive solution (H)]
The acrylic polymer (III) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-353, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass of this solution (solid content: 100 parts by mass). 4 parts by weight (solid content 0.4 parts by weight) obtained by diluting the product to 10% with ethyl acetate, and an alkali metal salt as an antistatic agent, lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO _{2 2} ) LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate 30 parts by mass (solid content 0.3 parts by mass), hexamethylene diisocyanate isocyanurate (Japan Polyurethane Industry Co., Ltd.) as a crosslinking agent Product, Coronate HX) 3 parts by mass (solid content 3 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (Mitsui Chemicals, Takenai) 600) 0.3 parts by mass (solid content 0.3 parts by mass) and 3 parts by mass (solid content 0.03 parts by mass) of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst were added, and the mixture was stirred. Acrylic pressure-sensitive adhesive solution (H) was prepared.

[Preparation of acrylic adhesive solution (I)]
The acrylic polymer (IV) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-353, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass of this solution (solid content: 100 parts by mass). 4 parts by weight (solid content 0.4 parts by weight) obtained by diluting the product to 10% with ethyl acetate, and an alkali metal salt as an antistatic agent, lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO _{2 2} ) LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate 30 parts by mass (solid content 0.3 parts by mass), hexamethylene diisocyanate isocyanurate (Japan Polyurethane Industry Co., Ltd.) as a crosslinking agent Product, Coronate HX) 3 parts by mass (solid content 3 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (Mitsui Chemicals, Takenate 00) 0.5 parts by mass (solid content 0.5 parts by mass), 3 parts by mass of dibutyltin dilaurate (1% by mass ethyl acetate solution) (solid content 0.03 parts by mass) as a crosslinking catalyst, and mixing and stirring. Acrylic pressure-sensitive adhesive solution (I) was prepared.

[Preparation of acrylic adhesive solution (J)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (KF-353, Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass (100 parts by mass of the solid content) of this solution. 2 parts by weight of a solution obtained by diluting the product with ethyl acetate to 10% (solid content: 0.2 parts by weight), as an alkali metal salt as an antistatic agent, lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO ₂ ) ₂ : LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate 15 parts by mass (solid content 0.15 parts by mass), and isocyanurate of hexamethylene diisocyanate (Japan Polyurethane Industry Co., Ltd.) as a crosslinking agent Manufactured, Coronate HX) 3.5 parts by mass (solid content 3.5 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (manufactured by Mitsui Chemicals, Inc. Nate 600) 0.3 parts by mass (solid content 0.3 parts by mass), and 0.5 parts by mass of iron (III) acetylacetonate (1% by mass ethyl acetate solution) (solid content 0.005 parts by mass) as a crosslinking catalyst ) Was added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (J).

[Preparation of acrylic adhesive solution (K)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and the organopolysiloxane (x-22-6266, Shin-Etsu Chemical) is added to 500 parts by mass (100 parts by mass of the solid content) of this solution. 2 parts by weight (solid content 0.2 parts by weight) of a solution obtained by diluting 10% by ethyl acetate with lithium acetate, and lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO ₂ ) ₂ : LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate 15 parts by weight (solid content 0.15 parts by weight), hexamethylene diisocyanate isocyanurate (Japanese polyurethane) as a crosslinking agent Kogyo Co., Ltd., Coronate HX) 3 parts by mass (solid content 3 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (Mitsui Chemicals, Nate 600) 0.3 parts by mass (solid content 0.3 parts by mass) and 3 parts by mass (solid content 0.03 parts by mass) of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst were added and mixed and stirred. The acrylic pressure-sensitive adhesive solution (K) was prepared.

[Preparation of acrylic adhesive solution (L)]
The acrylic polymer (I) solution (40% by mass) is diluted to 20% by mass with ethyl acetate. 2 parts by weight of a solution obtained by diluting the product with ethyl acetate to 10% (solid content: 0.2 parts by weight), as an alkali metal salt as an antistatic agent, lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO _{2 2} ) LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate 15 parts by mass (solid content 0.15 parts by mass), and the acrylic oligomer solution diluted to 10% by mass with ethyl acetate 5 3.5 parts by mass (solid content 0.5 parts by mass), as a crosslinking agent, isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) Solid content 3.5 parts by mass) and 1,3-bis (isocyanatomethyl) cyclohexane (Mitsui Chemicals, Takenate 600) 0.3 parts by mass (solid content 0.3 parts by mass), dilaurin as a crosslinking catalyst 3 parts by weight (0.03 parts by weight of solid content) of dibutyltin acid (1% by weight ethyl acetate solution) was added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (L).

[Preparation of urethane-based adhesive solution (M)]
As a polyol, 85 parts by mass of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) which is a polyol having three hydroxyl groups, Sanniks GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn = 3000) 13 which is a polyol having three hydroxyl groups 2 parts by mass of Sannix GP1000 (manufactured by Sanyo Kasei Co., Ltd., Mn = 1000), 18 parts by mass of an isocyanate compound coronate HX (manufactured by Nippon Polyurethane Co., Ltd.), and iron as a catalyst (III) 0.04 parts by mass of acetylacetonate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 210 parts by mass of ethyl acetate as a diluent solvent were obtained to obtain a urethane-based pressure-sensitive adhesive solution (M). In addition, as a raw material of a urethane type adhesive solution, all except a solvent are raw materials with a density | concentration of 100%.

[Preparation of urethane-based adhesive solution (N)]
A urethane-based pressure-sensitive adhesive solution (N) was obtained in the same manner as the urethane-based pressure-sensitive adhesive solution (M) except that 0.08 parts by mass of the tin-based catalyst dibutyltin dilaurate was used as a catalyst.

[Preparation of urethane-based adhesive solution (O)]
The urethane-based pressure-sensitive adhesive solution (excluding the addition of 30 parts by mass of isopropyl myristate (Exepal IPM, manufactured by Kao Corporation) as a wettability improver and 0.5 parts by mass of Irganox 1010 (manufactured by BASF) as an antioxidant ( In the same manner as in M), a urethane-based pressure-sensitive adhesive solution (O) was obtained.

[Preparation of urethane-based adhesive solution (P)]
As an antistatic component, 0.1 part by mass of organopolysiloxane (KF-6004, manufactured by Shin-Etsu Chemical Co., Ltd.), 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (EMIFSI, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) A urethane-based pressure-sensitive adhesive solution (P) was obtained in the same manner as the urethane-based pressure-sensitive adhesive solution (O) except that 0.5 part by mass was further added.

[Preparation of silicone adhesive solution (Q)]
As a silicone-based pressure-sensitive adhesive, “X-40-3229” (solid content 60% by mass, manufactured by Shin-Etsu Chemical Co., Ltd.) is 100 parts by mass in solid content, and as a platinum catalyst, “CAT-PL-50T” (Shin-Etsu Chemical Co., Ltd.). (Product) 0.5 parts by mass and 100 parts by mass of toluene as a solvent were blended to obtain a silicone-based pressure-sensitive adhesive solution (Q).

[Preparation of silicone adhesive solution (R)]
As a silicone-based adhesive, “X-40-3229” (solid content 60 mass%, manufactured by Shin-Etsu Chemical Co., Ltd.) is 100 mass parts in solid content, and “CAT-PL-50T” (manufactured by Shin-Etsu Chemical Co., Ltd.) as a platinum catalyst. 0.5 parts by weight, 0.2 parts by weight of organopolysiloxane (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.), lithium bis (trifluoromethanesulfonyl) imide (LiN (CF ₃ SO ₂ ) ₂ : LiTFSI, Tokyo Chemical Industry 0.3 parts by mass) and 100 parts by mass of toluene as a solvent were blended to obtain a silicone-based pressure-sensitive adhesive solution (R).

<Preparation of aqueous solution for antistatic layers (C), (G) and (H)>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aquapass, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co.) as a conductive polymer, and hexamethylene blocked with diisopropylamine as a crosslinking agent Isocyanurate of diisocyanate, lubricant, oleic amide in water / ethanol (1/3) mixed solvent, binder in solid content of 100 parts by mass, conductive polymer in solid content of 75 parts by mass, and crosslinker in solid form 10 parts by weight and 30 parts by weight of solid lubricant were added and stirred for about 20 minutes to mix thoroughly. In this way, an aqueous solution for antistatic layer (C) having an NV of about 0.4% was prepared.
Further, based on the contents of Table 4, an aqueous solution for antistatic layer (G) and an aqueous solution for antistatic layer (H) were prepared in the same manner as the aqueous solution for antistatic layer (C).

<Preparation of aqueous solution for antistatic layer (D)>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aquapass, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co.) as a conductive polymer, and hexamethylene blocked with diisopropylamine as a crosslinking agent An isocyanurate body of diisocyanate in a water / ethanol (1/3) mixed solvent, a binder in a solid content of 100 parts by mass, a conductive polymer in a solid content of 75 parts by mass, and a crosslinking agent in a solids content of 10 parts by mass. In addition, it was stirred for about 20 minutes and mixed well. In this way, an aqueous solution for antistatic layer (D) having an NV of about 0.4% was prepared.

<Preparation of aqueous solution for antistatic layer (E)>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as the binder, poly (3,4-ethylenedioxythiophene) (PEDOT) 0.5% and polystyrene sulfonate (weight average molecular weight 150,000) as the conductive polymer (PSS) 0.8% aqueous solution (Bytron P, manufactured by HC Stark Co.) in a water / ethanol (1/1) mixed solvent, 100 parts by mass of binder in solid content, and conductive polymer 50 parts by mass and a melamine-based cross-linking agent were added in a solid content, and the mixture was stirred and mixed well for about 20 minutes. In this way, an aqueous solution for antistatic layer (E) having an NV of about 0.4% was prepared.

<Preparation of aqueous solution for antistatic layer (F)>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, and polyaniline sulfonic acid (aquapass, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co.) as a conductive polymer is mixed in water / ethanol (1/3). To the solvent, 100 parts by mass of the binder in a solid amount and 75 parts by mass of the conductive polymer in a solid content were added, and the mixture was stirred and mixed well for about 20 minutes. In this way, an aqueous solution for antistatic layer (C) having an NV of about 0.4% was prepared.

<Preparation of base material with antistatic layer>
The antistatic layer (C) is applied to the corona-treated surface of a transparent polyethylene terephthalate (PET) film (polyester film) having a thickness of 38 μm, a width of 30 cm, and a length of 40 cm. ) To (H) were applied so that the thickness after drying was 15, 30, or 45 nm. The coated material was heated to 130 ° C. for 1 minute and dried to prepare a substrate with an antistatic layer having an antistatic layer on the first surface of the PET film.

<Example 1>
[Production of surface protective film]
The acrylic pressure-sensitive adhesive solution (A) is applied to the surface opposite to the antistatic layer of the base material having the antistatic layer (base material with antistatic layer), heated at 130 ° C. for 1 minute, A pressure-sensitive adhesive layer having a thickness of 15 μm was formed. Next, the surface of the pressure-sensitive adhesive layer was bonded with a silicone-treated surface of a polyethylene terephthalate film (thickness 25 μm), which is a separator with one side treated with silicone, to prepare a surface protective film.

<Example 15>
The urethane-based pressure-sensitive adhesive solution (N) is applied to the surface opposite to the antistatic layer of the base material having the antistatic layer (base with antistatic layer), heated at 130 ° C. for 1 minute, A pressure-sensitive adhesive layer having a thickness of 10 μm was formed.
Next, the surface of the pressure-sensitive adhesive layer was bonded with a silicone-treated surface of a polyethylene terephthalate film (thickness 25 μm), which is a separator with one side treated with silicone, to prepare a surface protective film.

<Example 19>
The silicone-based pressure-sensitive adhesive solution (Q) is applied to the surface opposite to the antistatic layer of the base material having the antistatic layer (base with antistatic layer), heated at 150 ° C. for 1 minute, A pressure-sensitive adhesive layer having a thickness of 10 μm was formed. Next, the surface of the pressure-sensitive adhesive layer was bonded with a silicone-treated surface of a polyethylene terephthalate film (thickness 25 μm), which is a separator with one side treated with silicone, to prepare a surface protective film.

<Examples 2 to 14 and Comparative Examples 1 to 3>
Based on the content of Table 1, Table 4, and Table 5, a surface protective film was produced in the same manner as in Example 1.

<Examples 16 to 18>
Based on the contents of Tables 2, 4 and 5, surface protective films were produced in the same manner as in Example 15.

<Example 20>
A surface protective film was produced in the same manner as in Example 19 based on the contents of Tables 3 to 5.

  Table 6 shows the results of various measurements and evaluations described above for the surface protective films according to Examples and Comparative Examples.

注）表中の「＞１.０Ｅ＋１３」とは１０の１３乗を超えることを示す。

Note) “> 1.0E + 13” in the table indicates that 10 exceeds the 13th power.

  From Table 6, it is excellent in the surface resistance value and film side peeling band voltage which an antistatic layer contributes in all the Examples, and also by using an isocyanate type crosslinking agent as a crosslinking agent used for an antistatic layer. It was also confirmed that the printing adhesion was excellent. Moreover, in Example 2 etc. which mix | blended the antistatic component with the adhesive layer, it is excellent also in polarizing plate peeling band voltage, and in Example 1 etc. which mix | blended the lubricant with the antistatic layer, it is excellent also in slipperiness. It could be confirmed.

  On the other hand, from Table 6, in Comparative Examples 1 and 2, when a water-dispersed conductive polymer (PEDOT / PSS) is used as a component constituting the antistatic layer, it is used when preparing the antistatic layer. Aggregates are observed in the aqueous solution, and the antistatic layer contributes not only to the surface resistance value over time (measured after one week at room temperature) and the film-side release voltage derived from the antistatic layer, It was also confirmed that the polarizing plate peeling voltage derived from the pressure-sensitive adhesive layer cannot obtain the desired effect. Although details are not clear as the reason, it is presumed that deterioration of the antistatic property occurred as a whole of the surface protective film based on the deterioration of the antistatic layer. Moreover, compared with the comparative example 1 which mix | blended the antistatic component with the adhesive layer, in the comparative example 2 which was not mix | blended, the polarizing plate peeling band voltage resulted in especially inferior.

  In Comparative Example 3, a water-soluble type conductive polymer (polyaniline sulfonic acid) was used as a component constituting the antistatic layer, but an isocyanate-based crosslinking agent was not used as a crosslinking agent. It was confirmed to be inferior.

  The surface protective film disclosed herein protects the optical member during manufacturing or transportation of an optical member used as a component of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescence (EL) display, or the like. Therefore, it is suitable as a surface protective film. In particular, surface protective films (optical surfaces) applied to optical members such as polarizing plates (polarizing films) for liquid crystal display panels, wave plates, phase difference plates, optical compensation films, brightness enhancement films, light diffusion sheets, and reflective sheets It is useful as a protective film.

1: Surface protective film 10: Acrylic plate 20: Polarizing plate 30: Sample fixing base 40: Potential measuring device 11: Antistatic layer 12: Base material 13: Adhesive layer

Claims (7)

A base material having a first surface and a second surface, an antistatic layer provided on the first surface of the base material, and a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition on the second surface of the base material A surface protection film comprising:
The surface protection film, wherein the antistatic layer is formed from an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent.   The surface protection film according to claim 1, wherein the antistatic agent composition further contains a fatty acid amide as a lubricant.   The surface protective film according to claim 1, wherein the substrate is a polyester film.   The pressure-sensitive adhesive composition contains at least one selected from the group consisting of an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive. The surface protective film as described.   The surface-protective film according to claim 1, wherein the pressure-sensitive adhesive composition contains an antistatic component.   An optical member protected by the surface protective film according to claim 1. It is a manufacturing method of the surface protection film in any one of Claims 1-5,
Preparing an aqueous solution containing the antistatic agent composition;
Applying the aqueous solution to the first surface of the substrate and drying to prepare an antistatic layer, and a method for producing a surface protective film.

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