JP6742723B2 - Surface protection film and optical member - Google Patents

Description

The present invention relates to a surface protection film and an optical member.

The present invention has 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. More specifically, the present invention relates to a surface protection film having an antistatic function. The surface protective film according to the present invention is suitable for applications such as being attached to a plastic product or the like that is prone to generate static electricity. In particular, as a surface protective film used for the purpose of protecting the surface of optical members (for example, polarizing plates, wavelength plates, retardation plates, optical compensation films, reflection sheets, brightness enhancement films used in liquid crystal displays, etc.) It is useful.

The surface protective film (also referred to as a surface protective sheet) generally has a structure in which a pressure-sensitive adhesive layer is provided on a film-shaped base material (support). Such a protective film is attached to an adherend (protected object) via the pressure-sensitive adhesive layer, and is used for the purpose of protecting the adherend from scratches and stains during processing and transportation. For example, a liquid crystal display panel is formed by bonding optical members such as a polarizing plate and a wave plate to a liquid crystal cell via an adhesive layer. In the production of such a liquid crystal display panel, a polarizing plate to be attached to a liquid crystal cell is used after being produced in a roll form, unrolled 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 scratched by rubbing against 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. The surface protective film is peeled off and removed when it is no longer needed.

In general, the surface protection film and the optical member are made of a plastic material, and therefore have high electric insulation and generate static electricity due to friction or peeling. Therefore, static electricity is easily generated even when the surface protective film is peeled off from the optical member such as the polarizing plate, and if a voltage is applied to the liquid crystal with the static electricity remaining, the alignment of liquid crystal molecules is lost, Moreover, there is a concern that the panel may be damaged. In addition, the presence of static electricity can also be a factor that attracts dust and reduces workability. Under such circumstances, antistatic treatment is performed on the surface protective film. For example, formation of an antistatic layer or application of an antistatic coating as a surface layer (top coat layer, back layer) of the surface protective film. Therefore, an antistatic function is provided (see Patent Document 1).

Further, in recent years, PEDOT (poly(3,4-ethylenedioxythiophene)/PSS (polystyrene sulfonate) (polythiophene type) has been used as a conductive polymer used to impart an antistatic function to the surface layer of a surface protective film. However, when the conductive polymer is used to form the antistatic layer, PSS (corresponding to the dopant) is desorbed from PEDOT and the surface of the antistatic layer is formed. The resistivity and peeling electrification voltage may increase, and there may be problems such as an increase (deterioration) in surface resistivity due to oxidative deterioration and photodegradation. When it occurs, static electricity is generated when the surface protective film is peeled off from the adherend, which may cause a problem.

JP, 2008-255332, A

Therefore, in view of the above circumstances, an object of the present invention is to provide a surface protective film and an optical member that can achieve antistatic properties and stability of peeling electrification voltage over time as a result of intensive research.

That is, the surface protective film of the present invention is 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 pressure-sensitive adhesive layer formed of an adhesive composition, wherein the antistatic layer is a conductive polymer component, polyanilinesulfonic acid, and polythiophenes doped with polyanions, and A polythiophene compound formed from an antistatic agent composition containing a binder, wherein the polyanilinesulfonic acid and the polythiophenes doped with the polyanions have a mixing ratio (mass ratio) of 90:10 to 10:90. It is characterized by being.

In the surface protection film of the present invention, the polythiophenes are preferably poly(3,4-ethylenedioxythiophene) (PEDOT).

In the surface protection film of the present invention, the polyanions are preferably polystyrene sulfonic acid (PSS).

In the surface protective film of the present invention, the binder is preferably a polyester resin.

In the surface protective film of the present invention, it is preferable that the antistatic agent composition contains a melamine-based crosslinking agent and/or an isocyanate-based crosslinking agent as a crosslinking agent.

In the surface protection film of the present invention, the antistatic agent composition contains, as a lubricant, at least one selected from the group consisting of fatty acid amides, fatty acid esters, silicone lubricants, fluorine lubricants, and wax lubricants. It is preferable.

In the surface protection 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 acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, and silicone pressure-sensitive adhesives.

In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains a polyether compound.

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 protection film.

In the surface protective film of the present invention, the antistatic layer provided on the first surface (back surface) of the substrate is formed from an antistatic agent composition containing a specific conductive polymer component in a specific ratio. By using the above, it is possible to provide an antistatic property based on the antistatic layer and a surface protective film capable of achieving stability of peeling electrification voltage over time, and an optical member, which is useful.

It is a typical sectional view showing one example of composition of a surface protection film concerning the present invention. It is explanatory drawing which shows the measuring method of peeling electrification voltage.

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

<Overall structure of surface protection film>
The surface protective film disclosed herein is in a form generally referred to as an adhesive sheet, an adhesive tape, an adhesive label, an adhesive film, and the like, and is particularly 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 protection film that protects the surface of an optical component when it is processed or conveyed. 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 dots or stripes. It may be an adhesive layer. The surface protective film disclosed herein may be in the form of a roll or a sheet.

A typical configuration example of the surface protection film disclosed herein is schematically shown in FIG. This surface protection film 1 includes a base material (for example, a polyester film) 12, an antistatic layer 11 provided on a first surface 12 of the base material 12, and a second surface of the base material 12 (on a 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 attaching the pressure-sensitive adhesive layer 13 to an adherend (a subject 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 being adhered to an adherend) has a surface (the surface to be adhered to the adherend) of the pressure-sensitive adhesive layer 13 which is a release surface at least on the pressure-sensitive adhesive layer 13 side. It may be in a form protected by a liner. Alternatively, even if the surface protective film 1 is wound in a roll shape, the pressure-sensitive adhesive layer 13 is in contact with the back surface of the substrate 12 (the surface of the antistatic layer 11) to protect the surface. Good.

As shown in FIG. 1, a mode in which the antistatic layer 11 is directly formed on the first surface of the base material 12 (without interposing other layers), and the antistatic layer 11 is exposed on the back surface of the surface protective film 1. (That is, the antistatic layer 11 also serves as the topcoat layer) has an antistatic layer in which the antistatic layer 11 is provided on the base material 12 as compared with a configuration in which the antistatic layer is provided separately from the topcoat layer. The film (and thus the surface protection film using the film) can reduce the number of layers constituting the surface protection film, and is therefore advantageous from the viewpoint of improving productivity.

<Substrate>
The surface protective film of the present invention is characterized by having a base material having a first surface (back surface) and a second surface (surface opposite to the first surface). In the technique disclosed herein, the resin material forming the base material can be used without particular limitation, and examples thereof include transparency, mechanical strength, thermal stability, moisture shielding property, isotropic property, and flexibility. It is preferable to use those having excellent properties such as properties 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, which is useful.

Examples of the base material (support) include polyester-based polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate-based polymers; poly. A plastic film composed of a resin material containing an acrylic polymer such as methyl methacrylate; or the like as a main resin component (a main component among resin components, typically 50% by mass or more) is used as the base material. It can be preferably used. Other examples of the resin material include styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer; olefin-based polymers such as polyethylene, polypropylene, polyolefin having a cyclic or norbornene structure, and ethylene-propylene copolymer; Examples of the resin material include vinyl chloride polymers; amide polymers such as nylon 6, nylon 6,6, and aromatic polyamides; As still another example of the resin material, an imide polymer, a sulfone polymer, a polyether sulfone polymer, a polyether ether ketone polymer, a polyphenylene sulfide polymer, a vinyl alcohol polymer, a vinylidene chloride polymer, a vinyl butyral polymer. , Arylate-based polymers, polyoxymethylene-based polymers, epoxy-based polymers and the like. It may be a substrate composed of a blend of two or more of the above-mentioned polymers.

A plastic film made of a transparent thermoplastic resin material can be preferably used as the base material. Among the plastic films, the use of a polyester film is a more preferable embodiment. Here, the polyester film is a film containing a polymer material (polyester resin) having a main skeleton based on an ester bond such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polybutylene terephthalate as a main resin component. Say. The polyester film has favorable properties as a base material for the surface protection film, such as excellent optical properties and dimensional stability, and has a property of being easily charged as it is.

Various additives such as antioxidants, ultraviolet absorbers, plasticizers, colorants (pigments, dyes, etc.), antistatic agents, antiblocking agents, etc. are added to the resin material constituting the base material, if necessary. It may have been done. The first surface of the polyester film (the surface on the side where the antistatic layer is provided) is, for example, known or commonly used for corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, undercoating agent coating and the like. The surface treatment may be applied. Such a surface treatment can be, for example, a treatment for increasing the adhesion between the base material and the antistatic layer. A surface treatment in which a polar group such as a hydroxyl group is introduced on the surface of the substrate can be preferably adopted. Further, the same surface treatment as described above may be applied to the second surface of the base material (the surface on the side where the adhesive layer is formed). Such surface treatment may be a treatment for enhancing the adhesion between the film and the pressure-sensitive adhesive layer (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 which has been subjected to an antistatic treatment as the base material. is there. The use of the base material is preferable because the surface protection film itself can be prevented from being charged when it is peeled off. Further, the base material is a plastic film, and by subjecting the plastic film to an antistatic treatment, it is possible to obtain an article in which the surface protection film itself has a reduced charge and the adherend has an excellent antistatic ability. The method for imparting the antistatic function is not particularly limited, and a conventionally known method can be used. For example, an antistatic resin or conductive polymer composed of an antistatic agent and a resin component, or a conductive substance can be used. Examples thereof include a method of applying a conductive resin contained therein, a method of depositing or plating a conductive substance, and a method of kneading an antistatic agent and the like.

The thickness of the substrate is usually 5 to 200 μm, preferably 10 to 150 μm. When the thickness of the base material is within the above range, the workability of attaching to the adherend and the workability of peeling from the adherend are excellent, which is preferable.

<Antistatic layer (top coat layer)>
The surface protection 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 protective film comprising an antistatic layer and a pressure-sensitive adhesive layer formed on the second surface of the base material with a pressure-sensitive adhesive composition, wherein the antistatic layer comprises a polyaniline sulfone as a conductive polymer component. Acid, and polythiophenes doped with polyanions, and those formed from an antistatic agent composition containing a binder, of polythiophenes doped with the polyanilinesulfonic acid and the polyonions The compounding ratio (mass ratio) is 90:10 to 10:90. When the surface protective film has an antistatic layer (top coat layer), the antistatic property of the surface protective film and the stability of the peeling electrification voltage over time are improved, which is a preferred embodiment. In particular, by blending the polyanilinesulfonic acid and polythiophenes doped with the polyonions within the above range, the polyanilinesulfonic acid alone or the polythiophenes doped with the polyonions alone. Although the stability of antistatic property over time is improved as compared with the case of blending, the following reasons are presumed. Polythiophenes doped with polyanions form a complex by coordinating the anion groups of polyanions with polythiophenes, and the conduction mechanism is the intramolecular conductivity of polythiophenes occurring in the complex, polythiophenes. It is known that the intermolecular conductivity of the compound and the conductivity between the complex structures. Here, the conduction between the composite structures is a rate-determining process because the intermolecular distance is large. In general, polyaniline sulfonic acid, which is a polymer higher than polythiophenes, is used together to connect the polyaniline sulfonic acid between the composites composed of polythiophenes and polyanions, and the conductive property of the polyaniline sulfonic acid itself leads to the conductivity between the composites. It is presumed that the antistatic property is improved and the stability is increased. By using these in combination, it becomes very useful as a surface protective film.

<Conductive polymer>
The antistatic layer is characterized by containing polyanilinesulfonic acid and polythiophenes doped with polyonions as conductive polymer components. Due to the combination of the conductive polymers, the polyanilinesulfonic acid plays a role in conducting the conduction between the complex structures of polythiophenes/polyanions as compared with the case where they are individually blended, so that the conductivity is enhanced and the antistatic property based on the antistatic layer is prevented. The stability and the peeling electrification voltage over time can be stabilized, which is useful.

The amount of the conductive polymer used is preferably 1 to 1000 parts by mass, more preferably 5 to 750 parts by mass, and still more preferably 100 parts by mass of the binder contained in the antistatic layer (top coat layer). Is 10 to 500 parts by mass. If the amount of the conductive polymer used is too small, the antistatic effect may be reduced, and if the amount of the conductive polymer used is too large, the adhesion to the base material of the antistatic layer may be reduced, or the transparency may be low. It is not preferable because it may decrease.

The polyanilinesulfonic 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. The weight average molecular weight of these conductive polymers is usually preferably 1×10 ³ or more, more preferably 5×10 ³ or more.

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

Examples of the polythiophenes used as the conductive polymer component include polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), Poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly( 3-bromothiophene), poly(3-chlorothiophene), poly(3-iodothiophene), poly(3-cyanothiophene), poly(3-phenylthiophene), poly(3,4-dimethylthiophene), poly( 3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly (3-heptyloxythiophene), poly(3-octyloxythiophene), poly(3-decyloxythiophene), poly(3-dodecyloxythiophene), poly(3-octadecyloxythiophene), poly(3,4- Dihydroxythiophene), poly(3,4-dimethoxythiophene), poly(3,4-diethoxythiophene), poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene), poly(3 ,4-dihexyloxythiophene), poly(3,4-diheptyloxythiophene), poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene), poly(3,4-di) Dodecyloxythiophene), poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butenedioxythiophene), poly(3-methyl-4-methoxy) Thiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene, poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), poly(3 -Methyl-4-carboxybutylthiophene), which may be used alone or in combination of two or more. Among them, poly(3,4-ethylene) is preferable from the viewpoint of conductivity. Dioxythiophene) (PEDOT) is preferred.

The polythiophenes have a degree of polymerization of preferably 2 to 1000, more preferably 5 to 100. It is preferable for it to be in the above-mentioned range since the conductivity is excellent.

The polyanions are polymers of constitutional units having an anion group, and act as a dopant for polythiophenes. Examples of the polyanions include polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamido-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, Polysulfoethyl methacrylate, poly(4-sulfobutyl methacrylate), polymethallyloxybenzenesulfonic acid, polyvinylcarboxylic acid, polystyrenecarboxylic acid, polyallylcarboxylic acid, polyacrylcarboxylic acid, polymethacrylcarboxylic acid, poly(2-acrylamide 2-Methylpropanecarboxylic acid), polyisoprenecarboxylic acid, polyacrylic acid, polysulfonated phenylacetylene, and the like. These may be homopolymers or copolymers of two or more types. Among them, polystyrene sulfonic acid (PSS) is preferable from the viewpoint of improving the conductivity and dispersibility of polythiophenes.

The weight average molecular weight (Mw) of the polyanions is preferably 1,000 to 1,000,000, more preferably 2,000 to 500,000. Within the above range, the doping and dispersibility in the polythiophenes are excellent, which is preferable.

Examples of commercially available polythiophenes doped with the polyanions include poly(3,4-ethylenedioxythiophene)/polystyrenesulfonic acid (PEDOT/PSS) under the trade name "Bytron P" manufactured by BAYER, Shin-Etsu. An example is a trade name “Sepul Gida” manufactured by Polymer Co., Ltd., and a trade name “Verazol” manufactured by Soken Kagaku Co., Ltd.

The antistatic agent composition has a mixing ratio (mass ratio) of the polyanilinesulfonic acid and polythiophenes doped with the polyanions (the polyanilinesulfonic acid:polythiophenes doped with the polyanions)), It is 90:10 to 10:90, preferably 85:15 to 15:85, and more preferably 80:20 to 20:80. Within the above range, the surface resistivity can be suppressed, and particularly, the stability of the surface resistivity over time is excellent, which is a preferred embodiment. Incidentally, in the case of the polyaniline sulfonic acid alone, the initial conductivity is low, so that the peeling electrification voltage and the surface resistivity are likely to increase over time, and in the case of the polythiophenes alone doped with the polyanions, the initial Although it has high conductivity, polyanions (corresponding to dopants) are more easily desorbed from polythiophenes over time, which is not preferable because the peeling electrification voltage and surface resistivity are likely to increase over time.

<Binder>
The antistatic layer contains a binder in order to impart solvent resistance, mechanical strength, and thermal stability. As the binder, acrylic resin, acrylic urethane resin, acrylic styrene resin, acrylic silicone resin, silicone resin, fluororesin, styrene resin, polyester resin, alkyd resin, polyurethane resin, amide resin, polyolefin resin, polysilazane resin, and their modification Alternatively, a copolymer resin may be used. Moreover, you may use the said resin individually or in combination of 2 or more types. Among the above resins, a polyester resin is preferably used because it has excellent solvent resistance.

The polyester resin is preferably a resin material containing polyester as a main component (typically more than 50% by mass, preferably 75% by mass or more, for example, 90% by mass or more). The polyester typically includes polyvalent carboxylic acids having two or more carboxyl groups in one molecule (typically dicarboxylic acids) and derivatives thereof (anhydrides, esterified products, halogens of the polyvalent carboxylic acids). Compound or the like) selected from 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 components) are condensed.

Examples of the compound that can be adopted as the polycarboxylic 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 Aliphatic dicarboxylic acids such as sebacic acid, brassic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid, and tetradecyldicarboxylic acid; cycloalkyldicarboxylic acid (for example, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), Alicyclic dicarboxylic acids such as 1,4-(2-norbornene)dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantanedicarboxylic acid, spiroheptanedicarboxylic acid; phthalic acid, isophthalic acid, dithio Isophthalic acid, methylisophthalic acid, dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorangecarboxylic acid, anthracenedicarboxylic acid , Biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4"-p-terephenylenedicarboxylic acid, 4,4"-p-quarrelphenyldicarboxylic acid, bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid , Phenylenediacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyldiacetic acid, biphenyldipropionic acid, 3,3'-[4,4'-(methylenedi-p-biphenylene)dipropionic acid, Aromatic dicarboxylic acids such as 4,4′-bibenzyldiacetic acid, 3,3′(4,4′-bibenzyl)dipropionic acid, oxydi-p-phenylenediacetic acid; acids of any of the above-mentioned polycarboxylic acids Anhydride; S of any of the above polyvalent carboxylic acids Tell (eg alkyl ester. It can be a monoester, a diester and the like. ); an acid halide (for example, dicarboxylic acid chloride) corresponding to any of the above-mentioned polyvalent carboxylic acids; and the like.

Preferred examples of the compound that can be used as the polyvalent carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalene dicarboxylic 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 their acid anhydrides; and lower alkyl esters of the dicarboxylic acids (for example, with monoalcohols having 1 to 3 carbon atoms) Ester) and the like.

On the other hand, examples of compounds that can be adopted 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 of these compounds (eg, ethylene oxide adducts, propylene oxide adducts, etc.).

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

As the polyester resin, for example, product names Bayronal MD-1100, MD-1200, MD-1245, MD-1335, MD-1480, MD-1500, MD-1930, MD-1985, MD-2000 manufactured by Toyobo Co., Ltd. , Trade name, plus coat Z-221, Z-446, Z-561, Z-565, Z-880, Z-3310, RZ-105, RZ-570, Z-730, Z-760 manufactured by Kyodo Chemical Industry Co., Ltd. , Z-592, Z-687, Z-690, PESRESIN A-110, A-120, A-124GP, A-125S, A-160P, A-520, A-613D, A-615GE manufactured by Takamatsu Yushi Co., Ltd. , A-640, A-645GH, A-647GEX, A-680, A-684G, WAC-14, WAC-17XC and the like.

The antistatic layer (top coat layer) is a binder other than polyester resin (eg, acrylic resin) as long as the performance (eg, antistatic property) of the surface protective film disclosed herein is not significantly impaired. Resin, acrylic urethane resin, acrylic styrene resin, acrylic silicone resin, silicone resin, fluororesin, styrene resin, alkyd resin, polyurethane resin, amide resin, polyolefin resin, polysilazane resin, etc., or their modified or copolymerized resin. Or one or more resins). In a preferred embodiment of the technology disclosed herein, the binder of the antistatic layer is substantially composed of polyester resin. For example, an antistatic layer in which the proportion of polyester resin in the binder is 98 to 100% by 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 suitable.

<Lubricant>
The antistatic layer (topcoat layer) in the technology disclosed herein comprises, as a lubricant, at least one selected from the group consisting of fatty acid amides, fatty acid esters, silicone lubricants, fluorine lubricants, and wax lubricants. It is the preferred embodiment to use. A mode in which the release of the antistatic layer is not further performed by using the lubricant (for example, a known release agent such as a silicone release agent or a long-chain alkyl release agent is applied and dried). Also in this case, since an antistatic layer (top coat layer) having both sufficient slipperiness and print adhesion can be obtained, it can be a preferable embodiment. As described above, the embodiment in which the surface of the antistatic layer is not further subjected to the peeling treatment may prevent the whitening (for example, the whitening due to the storage under the heating and humidifying conditions) caused by the peeling treatment agent. It is preferable in terms. It is also advantageous in terms of solvent resistance.

Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, N-oleylpaltimic acid amide, and N-stearyl stearic acid. Amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid Amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisbehenic acid amide, hexamethylenebisbehenic acid amide, hexamethylenehydroxystearic acid amide, N,N'-distearyl adipate amide, N,N ′-Distearyl sebacic acid amide, ethylenebisoleic acid amide, ethylenebiserucic acid amide, hexamethylenebisoleic acid amide, N,N′-dioleyl adipamic acid amide, N,N′-dioleyl sebacic acid amide, m -Xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-stearylisophthalic acid amide and the like can be mentioned. These lubricants may be used alone or in combination of two or more.

Specific examples of the fatty acid ester include polyoxyethylene bisphenol A lauric acid ester, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, behenic acid monoglyceride, cetyl 2-ethylhexanoate, isopropyl myristate, palmitine. Isopropyl acid, cholesteryl isostearate, lauryl methacrylate, methyl coconut fatty acid, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol Examples include tetrapalmitate, stearyl stearate, isotridecyl stearate, triglyceride 2-ethylhexanoate, butyl laurate, octyl oleate and the like. These lubricants may be used alone or in combination of two or more.

Specific examples of the silicone lubricant include polydimethylsiloxane, polyether modified polydimethylsiloxane, amino modified polydimethylsiloxane, epoxy modified polydimethylsiloxane, carbinol modified polydimethylsiloxane, mercapto modified polydimethylsiloxane, and carboxyl modified polydimethyl. Siloxane, methyl hydrogen silicone, methacryl modified polydimethylsiloxane, phenol modified polydimethylsiloxane, silanol modified polydimethylsiloxane, aralkyl modified polydimethylsiloxane, fluoroalkyl modified polydimethylsiloxane, long chain alkyl modified polydimethylsiloxane, higher fatty acid modified ester Examples include modified polydimethylsiloxane, higher fatty acid amide modified polydimethylsiloxane, and phenyl modified polydimethylsiloxane. These lubricants may be used alone or in combination of two or more.

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

Specific examples of the wax lubricant include petroleum wax (paraffin wax etc.), vegetable wax (carnauba wax etc.), mineral wax (Montan wax etc.), higher fatty acid (cerotic acid etc.) and neutral fat (palmitin). Various waxes such as acid triglyceride). These lubricants may be used alone or in combination of two or more.

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

<Crosslinking agent>
The antistatic layer preferably contains, as a cross-linking agent, at least one selected from the group consisting of a silane coupling agent, an epoxy-based cross-linking agent, a melamine-based cross-linking agent, and an isocyanate-based cross-linking agent. It is a preferred embodiment to use the melamine-based crosslinking agent and/or the isocyanate-based crosslinking agent. An electrically conductive polymer component that is an essential component when forming an antistatic layer, polyanilinesulfonic acid, and polythiophenes doped with polyanions can be fixed in a binder, and excellent in water resistance and solvent resistance. Further, it is possible to realize effects such as improvement of print adhesion. In particular, by using a melamine-based cross-linking agent, water resistance and solvent resistance are improved, by using an isocyanate-based cross-linking agent, water resistance and print adhesion are improved, and by using these cross-linking agents in combination, , Water resistance, solvent resistance, and print adhesion are improved, which is useful.

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

Further, it is a preferred embodiment that a blocked isocyanate-based crosslinking agent that is stable in an aqueous solution is used as the isocyanate-based crosslinking agent. Specific examples of the blocked isocyanate-based cross-linking agent include isocyanate-based cross-linking agents that can be used in the preparation of general pressure-sensitive adhesive layers and antistatic layers (top coat layers) (for example, used in the pressure-sensitive adhesive layer described below. Isocyanate compounds) to alcohols, phenols, thiophenols, amines, imides, oximes, lactams, active methylene compounds, mercaptans, imines, ureas, diaryl compounds, and sodium bisulfite. You can use the one blocked with.

The antistatic layer in the technology disclosed herein, if necessary, other antistatic components, antioxidants, colorants (pigments, dyes, etc.), fluidity modifiers (thixotropic agents, thickeners, etc.), It may contain additives such as a film-forming aid, a surfactant (such as a defoaming agent), and a preservative. It is also possible to contain a glycidyl compound, a polar solvent, a polyhydric aliphatic alcohol, a lactam compound, etc. as the conductivity improver.

<Formation of antistatic layer>
The antistatic layer (topcoat layer) is a liquid composition (antistatic layer) in which essential components such as the conductive polymer component and additives used as necessary are dissolved or dispersed in a suitable solvent (such as water). It can be suitably formed by a method including applying a coating material for formation, an antistatic agent composition) to a substrate. For example, a method of applying the coating material to the first surface of the base material, drying the coating material, and performing a curing treatment (heat treatment, ultraviolet treatment, etc.) as necessary can be preferably adopted. 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% by mass) is suitable. When forming an antistatic layer having a small thickness, the NV of the coating material is preferably 0.05 to 0.50% by mass (e.g. 0.10 to 0.40% by mass). By using the low NV coating material as described above, a more uniform antistatic layer can be formed.

The solvent constituting the antistatic layer-forming coating material is preferably one that can stably dissolve or disperse the components for forming the antistatic layer. 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 compounds 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, cyclohexanol; alkylene glycol monoalkyl ethers (for example, ethylene glycol monomethyl ether) , Ethylene glycol monoethyl ether), dialkylene glycol monoalkyl ether, and other glycol ethers; and the like. In a preferred aspect, 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).

Further, in order to improve dispersion stability in a solvent, it is possible to include a basic organic compound capable of coordinating or binding to the anion group of the polyanions as an ion pair. Examples of the basic organic compound include known amine compounds, amine compound hydrochlorides, cationic emulsifiers, and basic resins.

Specific examples of the basic organic compound include methyloctylamine, methylbenzylamine, N-methylaniline, dimethylamine, diethylamine, diethanolamine, N-methylethanolamine, di-n-propylamine, diisopropylamine, methyl- Isopropanolamine, dibutylamine, di-2-ethylhexylamine, aminoethylethanolamine, 3-amino-1-propanol, isopropylamine, monoethylamine, 2-ethylhexylamine, t-butylamine, N-(2-aminoethyl)- 3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, Amine compounds such as 3-aminopropyltriethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane, hydrochlorides of primary amines such as monomethylamine, monoethylamine and stearylamine, dimethylamine, diethylamine and distearylamine. Secondary amine hydrochlorides, tertiary amine hydrochlorides such as trimethylamine, triethylamine, stearyldimethylamine, etc., quaternary ammonium salts such as stearyltrimethylammonium chloride, distearyldimethylammonium chloride, stearyldimethylbenzylammonium chloride, monoethanolamine Hydrochlorides of ethanolamines such as diethanolamine and triethanolamine, and hydrochlorides of polyethylene polyamines such as ethylenediamine and diethylenetriamine.

Specific examples of the cationic emulsifier include alkylammonium salt, alkylamidobetaine, alkyldimethylamine oxide and the like.

Specific examples of the basic resin include polyester-based, acrylic-based, and urethane-based polymer copolymers having a weight average molecular weight (Mw) of 1,000 to 1,000,000. If the weight average molecular weight of the basic resin is less than 1000, sufficient steric hindrance may not be obtained, and the dispersing effect may be reduced. Even if the weight average molecular weight is more than 1,000,000, agglomeration may occur. ..

The amine value of the basic resin is preferably 5 to 200 mgKOH/g. If it is less than 5 mgKOH/g, the interaction with the polyanions doped in the polythiophenes tends to be insufficient, and a sufficient dispersion effect may not be obtained. On the other hand, when the amine value of the basic resin exceeds 200 mgKOH/g, the steric hindrance layer becomes smaller than the affinity part for the polyanions doped in the polythiophenes, and the dispersion effect may be insufficient.

Examples of the basic resin include Solsperse 17000, Solsperse 20000, Solsperse 24000, Solsperse 32000 (manufactured by Zeneca Corporation), Disperbyk-160, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk, Diperbyk, Diperbyk, Diperbyk. (Manufactured by Big Chemie), Azisper PB711, Azisper PB821, Azisper PB822, Azisper PB824 (manufactured by Ajinomoto Co., Inc.), Epomin 006, Epomin 012, Epomin 018 (manufactured by Nippon Shokubai Co., Ltd.), EFKA4046, EFKA4330, EFKA4330, EFKAA. Manufactured by Kusumoto Kasei Kagaku Co., etc., and they can be used alone or in combination. Particularly, Azisper PB821, Azisper PB822, and Azisper PB824 are preferable in terms of dispersibility and conductivity during use.

The amount of the basic compound used is not limited, but is in the range of 1 part by mass to 100,000 parts by mass, preferably 10 parts by mass to 10,000 parts by mass with respect to 100 parts by mass of the total amount of the polythiophenes and the polyanions. It is preferably added.

<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, in the thickness of the antistatic layer, the thickness varies depending on the location). Unevenness may easily occur. On the other hand, if it is too thick, it may affect the characteristics of the substrate (optical characteristics, dimensional stability, etc.).

In a preferred embodiment of the surface protective film disclosed herein, the surface resistivity (Ω/□) measured on the surface of the antistatic layer is preferably less than 1.0×10 ¹¹ , and more preferably , 5.0×10 ^{10 or} less, and more preferably 1.0×10 ^{10 or} less. The surface protective film having a surface resistivity within the above range can be preferably used as a surface protective film used in the processing or transportation of articles such as liquid crystal cells and semiconductor devices that are sensitive to static electricity. The surface resistivity can be calculated from the surface resistivity measured in 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 a water-based ink or an oil-based ink (for example, using an oil-based marking pen). Such a surface protective film, in the process of processing or transporting the adherend (eg optical components) performed in a state where the surface protective film is attached, the identification number of the adherend to be protected is added to the surface protective film. Suitable to describe and display. Therefore, it is preferable that the surface protective film has excellent printability. For example, it is preferable that the solvent is alcoholic and has high printability with respect to oil-based inks of the type containing a pigment. Further, it is preferable that the printed ink is difficult to be removed due to rubbing or transfer (that is, the printing adhesion is excellent). The surface protective film disclosed herein may also have solvent resistance to such an extent that when the print is corrected or erased, the print does not noticeably change even if it is wiped off with alcohol (eg, ethyl alcohol). preferable.

The surface protection film disclosed herein may be embodied also in an embodiment including other layers in addition to the substrate, the pressure-sensitive adhesive layer, and the antistatic layer. Examples of the arrangement of such "another layer" include between the second surface (front surface) of the substrate and the pressure-sensitive adhesive layer. The layer arranged between the front surface of the substrate and the pressure-sensitive adhesive layer may be, for example, an undercoat layer (anchor layer) that enhances the anchoring property of the pressure-sensitive adhesive layer to the second surface, an antistatic layer, or the like. The surface protection film may have a structure 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 protection film of the present invention has the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition, as long as it has adhesiveness, It can be used without particular limitation, and for example, an acrylic adhesive, a urethane adhesive, a synthetic rubber adhesive, a natural rubber adhesive, a silicone adhesive, and the like can also be used, and among them, an acrylic adhesive is more preferable. It is at least one selected from the group consisting of pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives, and it is particularly preferable to use an acrylic pressure-sensitive adhesive that uses a (meth)acrylic polymer. ..

When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, the (meth)acrylic polymer forming the acrylic pressure-sensitive adhesive has an alkyl group having 1 to 14 carbon atoms as a raw material monomer forming the pressure-sensitive adhesive (meth). ) Acrylic monomers can be used as the main monomer. As said (meth)acrylic-type monomer, 1 type(s) or 2 or more types can be used. By using the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it becomes easy to control the peeling force (adhesive force) to an adherend (protected object) to be low, and light peeling A surface protective film having excellent properties and removability can be obtained. The (meth)acrylic polymer in the present invention means an acrylic polymer and/or a methacrylic polymer, and the (meth)acrylate means an acrylate and/or a methacrylate.

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 and the like. To be

Among them, 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. (Meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate and the like having 6 to 14 carbon atoms. Preferable examples are (meth)acrylic monomers having an alkyl group. In particular, by using a (meth)acrylic monomer having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the peeling force (adhesive force) to an adherend to be low and the removability is excellent. Becomes

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 60% by mass or more, further preferably 70 to 99% by mass, and most preferably 80 to 98% by mass. When it is less than 50% by mass, the wettability of the pressure-sensitive adhesive composition and the cohesive force of the pressure-sensitive adhesive layer are deteriorated, which is not preferable.

Further, in the pressure-sensitive adhesive composition of the present invention, it is preferable that the (meth)acrylic polymer contains a hydroxyl group-containing (meth)acrylic monomer as a raw material monomer. As the hydroxyl group-containing (meth)acrylic monomer, one kind or two or more kinds can be used.

By using the above-mentioned hydroxyl group-containing (meth)acrylic monomer, it becomes easier to control the crosslinking of the pressure-sensitive adhesive composition and the balance between improvement of wettability by flow and reduction of peeling force (adhesive force) during peeling is achieved. Easy to control. Further, unlike a carboxyl group or a sulfonate group that can generally act as a crosslinking site, a hydroxyl group has an appropriate interaction with an ionic compound that is an antistatic component (antistatic agent) or a polyether compound. Also, in terms of antistatic property, it can be preferably used.

Examples of the hydroxyl group-containing (meth)acrylic monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. , 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, N-methylol (meth)acrylamide, etc. Can be given. In particular, it is preferable to use a hydroxyl group-containing (meth)acrylic monomer in which the alkyl group has 4 or more carbon atoms because light peeling at high speed peeling is facilitated.

With respect to 100 parts by mass of the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the hydroxyl group-containing (meth)acrylic monomer is preferably contained in an amount of 25 parts by mass or less, more preferably , 1 to 22 parts by mass, more preferably 2 to 20 parts by mass, and most preferably 3 to 18 parts by mass. Within the above range, the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the obtained pressure-sensitive adhesive layer can be easily controlled, which is preferable.

Further, as other polymerizable monomer components, Tg is set to 0° C. or lower (usually −100° C. or higher) for the reason that the adhesive performance is easily balanced, and the glass transition temperature and peeling of the (meth)acrylic polymer are A polymerizable monomer or the like for adjusting the properties can be used within a range that does not impair the effects of the present invention.

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

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

The carboxyl group-containing (meth)acrylic monomer is preferably 5 parts by mass or less, and preferably 3 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. The amount is more preferably the following, more preferably 2 parts by mass or less, and most preferably 0.01 parts by mass or more and less than 0.1 parts by mass. When it exceeds 5 parts by mass, a large number of acid functional groups such as carboxyl groups having a large polar action are present, and when an ionic compound or a polyether compound that is an antistatic component (antistatic agent) is compounded, Interaction of an acid functional group such as a carboxyl group with the preventive component may hinder ionic conduction, reduce the conductivity efficiency, and prevent sufficient antistatic properties from being obtained, which is not preferable.

Further, a (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms, a hydroxyl group-containing (meth)acrylic monomer, and a carboxyl group-containing (meth)acrylic system used in the (meth)acrylic polymer. As the other polymerizable monomer other than the monomer, any polymerizable monomer may be used without particular limitation as long as it does not impair the characteristics of the present invention. For example, cohesive force/heat resistance improving components such as cyano group-containing monomers, vinyl ester monomers, and aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine. A component having a functional group such as a vinyl ether monomer which improves the peeling force (adhesive force) or serves as a cross-linking base point can be appropriately used. Among them, it is preferable to use a cyano group-containing monomer, an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, and a nitrogen-containing monomer such as N-acryloylmorpholine. By using the nitrogen-containing monomer, it is possible to secure an appropriate peeling force (adhesive force) without causing floating or peeling, and to obtain a surface protective film having excellent shearing force, which is useful. These polymerizable monomers may be used either individually or in combination of two or more.

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

Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethyl. Methacrylamide, N,N'-methylenebisacrylamide, N,N-dimethylaminopropyl acrylamide, N,N-dimethylaminopropyl methacrylamide, diacetone acrylamide and the like can be mentioned.

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

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

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

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

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 hydroxyl group-containing (meth)acrylic monomer, the carboxyl group-containing (meth)acrylic monomer, It is preferably 0 to 40 parts by mass, and more preferably 0 to 30 parts by mass, relative 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 or a polyether compound as an antistatic component is used, good interaction and good removability are adjusted appropriately. be able to.

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

The average addition mole number of oxyalkylene units of the alkylene oxide group-containing reactive monomer is from 1 to 40 from the viewpoint of compatibility with the ionic compound which is the antistatic component and the polyether compound. It is preferably 3 to 40, more preferably 4 to 35, still more preferably 5 to 30. When the average number of added moles is 1 or more, the effect of reducing contamination of the adherend (protected object) tends to be efficiently obtained. Further, when the average number of added moles is more than 40, the interaction with the ionic compound or the polyether compound is large, and the viscosity of the pressure-sensitive adhesive composition increases, which tends to make coating difficult, which is preferable. Absent. In addition, 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 the monomer components of the (meth)acrylic polymer. It is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, further preferably 4% by mass or less, and 3% by mass or less. It is particularly preferable that the amount is 1% by mass or less. When the content of the alkylene oxide group-containing reactive monomer exceeds 20% by mass, the interaction with the ionic compound or the polyether compound becomes large, the ionic conduction is hindered, and the antistatic property is deteriorated, which is preferable. Absent.

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, and examples thereof include an oxymethylene group, an oxyethylene group, an oxypropylene group, and an oxybutylene group. To be The hydrocarbon group of the oxyalkylene chain may be linear or branched.

Further, it is more preferable that the alkylene oxide group-containing reactive monomer is a reactive monomer having an ethylene oxide group. By using a reactive monomer-containing (meth)acrylic polymer having an ethylene oxide group as the base polymer, the compatibility of the base polymer with the ionic compound as the antistatic component and the polyether compound is improved, and the adhesion is improved. Bleeding to the body is suitably suppressed, and a low-staining 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 a reactive substituent 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, lauropolyethylene Examples thereof include glycol (meth)acrylate, stearoxy polyethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate, and octoxy polyethylene glycol-polypropylene glycol (meth)acrylate.

Further, 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, a cationic reactive surfactant, and the like. Can be given.

The weight average molecular weight (Mw) of the (meth)acrylic polymer is preferably 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, and further preferably 300,000 to 3,000,000. When the weight average molecular weight is less than 100,000, adhesive strength tends to occur due to a decrease in 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 and the adherend (for example, a polarizing plate) is insufficiently wetted, resulting in the adherend and the pressure-sensitive adhesive layer of the surface protective film. It tends to cause blisters that occur between. The weight average molecular weight refers to that obtained by measurement 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 hard to flow, for example, the wetting of the polarizing plate becomes insufficient, which tends to cause blistering between the polarizing plate and the pressure-sensitive adhesive layer of the surface protective film. There is. In particular, by setting the glass transition temperature to -61°C or lower, it becomes easy to obtain a pressure-sensitive adhesive layer having excellent wettability to a polarizing plate and light peeling property. The glass transition temperature of the (meth)acrylic polymer can be adjusted within the above range by appropriately changing the monomer components used and the composition ratio.

The method of polymerizing the (meth)acrylic polymer is not particularly limited, and it can be polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. Solution polymerization is a more preferable aspect from the viewpoint of characteristics such as low contamination to the adherend (object to be protected). The polymer obtained may be a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, or the like.

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

When a silicone-based pressure-sensitive adhesive is used for the pressure-sensitive adhesive layer, any suitable silicone-based pressure-sensitive adhesive can be adopted. As such a silicone-based pressure-sensitive adhesive, those obtained by blending or aggregating a silicone resin (silicone-based polymer, silicone component) can be preferably adopted.

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

As the curing reaction of the addition reaction-curable silicone-based pressure-sensitive adhesive, for example, when a polyalkylsilicone-based pressure-sensitive adhesive is obtained, a method of generally 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 forming 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 an alkali metal salt and/or an ionic liquid. By containing these ionic compounds, excellent antistatic properties can be imparted. The pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition containing the antistatic component as described above (using the antistatic component) is an adherend that is not antistatic when peeled (for example, a polarizing plate. ) Is prevented, and the surface protection film has reduced contamination on the adherend. Therefore, it is very useful as an antistatic surface protective film in the technical field related to optical/electronic parts in which charging and contamination are particularly serious problems.

Since the alkali metal salt has a high ionic dissociation property, it is preferable in that it exhibits an excellent antistatic ability even when added in a small amount. Examples of the alkali metal salt include a cation composed of Li ⁺ , Na ⁺ , and 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 H 4 (CH 3) SO 3 -, (C 2 F 5) 3 PF 3 -, CH 3 CH (OH) COO -, _{and, (FSO 2) 2} N ^- from A metal salt composed of the following anion is preferably used. 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, and 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 is 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 property. Although the details of why excellent antistatic properties are obtained by using an ionic liquid are not clear, ionic liquids have a lower melting point (melting point 100°C or less) than ordinary ionic compounds, so molecular motion is easy. Therefore, it is considered that excellent antistatic ability can be obtained. Particularly, when antistatic to the adherend is attempted, it is considered that the ionic liquid is transferred to the adherend in an extremely small amount, whereby the excellent antistatic property of peeling on the adherend is achieved. In particular, an ionic liquid having a melting point of room temperature (25° C.) or lower can transfer to an adherend more efficiently, and therefore, excellent antistatic property can be obtained.

Further, since the ionic liquid is liquid at any temperature of 100° C. or lower, it can be easily added to the pressure-sensitive adhesive and dispersed or dissolved as compared with a solid salt. Further, since the ionic liquid has no vapor pressure (nonvolatile), it has a characteristic that it does not disappear over time and the antistatic property is continuously obtained. The ionic liquid refers to a molten salt (ionic compound) which has a melting point of 100° C. or lower and is in a liquid state.

As the ionic liquid, those composed of an organic cation component represented by the following general formulas (A) to (E) and an anion component are preferably used. By using the ionic liquid having these cations, it is possible to obtain an ionic liquid having further excellent antistatic ability.

R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms, which 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 Are the same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may be a functional group in which a part of the hydrocarbon group is 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 and R _f. , And R _g are the same or different and each represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and a functional group in which a part of the hydrocarbon group is substituted with a hetero atom may be used.

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

Z in the above 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. Alternatively, 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 R _o .

R _P in the formula (E) represents a hydrocarbon group having 1 to 18 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a hetero atom.

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-propylpyrrolidinide Cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium Cation, 1-ethyl-1-propylpyrrolidinium 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-propylpipe Peridinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidin cation 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 Examples include -1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole cation, and N-ethyl-N-methylmorpholinium cation. To be

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

As a specific example, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-to Xyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazole Lithium 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-methoxyethyl)-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 cation And a 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation and the like.

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 Examples include -propyl-2,3,5-trimethylpyrazolinium cation and 1-butyl-2,3,5-trimethylpyrazolinium cation.

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 substituted with an alkenyl group, an alkoxyl group, or an epoxy group. There are things such as things.

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 cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, diallyldimethyl Examples thereof include ammonium cation and tributyl-(2-methoxyethyl)phosphonium cation. Among them, 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-propylammonium cation, N,N-dimethyl-N-ethyl-N-butylammonium cation, N,N-dimethyl-N-ethyl-N-pentylammonium cation, N,N-dimethyl -N-ethyl-N-hexyl ammonium cation, N,N-dimethyl-N-ethyl-N-heptyl ammonium cation, N,N-dimethyl-N-ethyl-N-nonyl ammonium 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-hexyl ammonium cation, N,N-dimethyl-N-propyl-N-heptyl ammonium cation, N,N-dimethyl-N-butyl-N-hexyl ammonium cation, N,N-diethyl-N-butyl-N- Heptyl ammonium cation, N,N-dimethyl-N-pentyl-N-hexyl ammonium cation, N,N-dimethyl-N,N-dihexyl ammonium cation, trimethyl heptyl ammonium cation, N,N-diethyl-N-methyl-N -Propyl ammonium cation, N,N-diethyl-N-methyl-N-pentyl ammonium cation, N,N-diethyl-N-methyl-N-heptyl ammonium cation, N,N-diethyl-N-propyl-N-pentyl cation Ammonium 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-dihexyl ammonium cation, N,N-dibutyl-N-methyl-N-pentyl ammonium cation, N,N-dibutyl-N-methyl-N-hexyl ammonium cation, trioctyl methyl ammonium cation, N-methyl- The N-ethyl-N-propyl-N-pentylammonium cation is preferably used.

Examples of the cation represented by the formula (E) include a sulfonium cation and the like. Further, specific examples of R _P in the formula (E) include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tridecyl group, a tetradecyl group, Examples include octadecyl group.

On the other hand, the anion component is not particularly limited as long as it satisfies the requirement of becoming an ionic liquid, and 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 -, C 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.

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

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

Specific examples of the ionic liquid used in the present invention are appropriately selected and used from the 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-pentylpyrrolidinium bis(trifluoromethanesulfonyl)imide , 1-methyl-1-hexylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-heptylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-propylpyrrolidinium bis To (trifluoromethanesulfonyl)imide, 1-ethyl-1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-pentylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1- Xylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-heptylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1,1-dipropylpyrrolidinium bis(triple oromethanesulfonyl)imide, 1 -Propyl-1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1,1-dibutylpyrrolidinium bis(triple oromethanesulfonyl)imide, 1-propylpiperidinium bis(trifluoromethanesulfonyl)imide, 1- Pentyl biveridinium bis(trifluoromethanesulfonyl)imide, 1,1-dimethylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-ethylpiperidinium 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(trifluoromethanesulfonyl) ) Imido, 1-ethyl-1-hexylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-heptylpiperidinium bis(trifluoromethanesulfonyl)imide, 1,1-dipropylpiperidinium Bis(trifluoromethanesulfonyl)imide, 1-propyl-1-butylpiperidinium pis(trifluoromethanesulfonyl)imide, 1,1-dibutylpiperidinium bis(trifluoromethanesulfonyl)imide, 1,1-dimethylpyrrolidinium Bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-ethylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl -1-Butylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-pentylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-hexylpyrrolidinium bis(pentafluoro Ethanesulfonyl)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(pentafluoroethanesulfonyl) Imi 1,1-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(penta Fluoroethanesulfonyl)imide, 1,1-dimethylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-ethylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-propylpi Peridinium bis(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 (Pentafluoroethanesulfonyl)imide, 1-ethyl-1-butylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-pentylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl- 1-hexylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-heptylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1,1-dipropylpiperidinium bis(pentafluoroethane) Sulfonyl)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- Methyl imidazolium Acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazo Lithium perfluorobutane sulfonate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(pentafluoroethanesulfonyl) Imido, 1-ethyl-3-methylimidazolium tris(trifluoromethanesulfonyl)methide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 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 tetra Fluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methyl Imidazolium 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(trifluoro Methanesulfonyl)imide, 1-butyl-2,3,5-trimethylpyrazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-2,3,5-trimethyl 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 Rhomethanesulfonyl)trifluoroacetamide, 1-butyl-2,3,5-trimethylpyrazolium bis(trifluoromethanesulfonyl)trifluoroacetamide, 1-ethyl-2,3,5-trimethylpyrazolinium bis(trifluoromethanesulfonyl) ) Imido, 1-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-Trimethylpyrazolinium 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, tetrapentyl ammonium trifluoromethane sulfonate, tetrapentyl ammonium bis( Trifluoromethanesulfonyl)imide, tetrahexylammonium trifluoromethanesulfonate, tetrahexylammonium bis(trifluoromethanesulfonyl)imide, tetrahebutylammonium trifluoromethanesulfonate, tetraheptylammonium bis(trifluoromethanesulfonyl)imide, diallyldimethylammonium tetrafluoroborate, Diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis( Lifluoromethanesulfonyl)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-propylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-ethyl-N-butylammonium bis(trifluoro Methanesulfonyl)imide, N,N-dimethyl-N-ethyl-N-pentylammonium bis(trifluoromethanesulfonyl)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-propyl-N-butylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-propyl-N-pentyl Ammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-propyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-propyl-N-heptylammonium bis(trifluoromethanesulfonyl) ) Imido, 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-hexyl ammonium bis(trifluoromethanesulfonyl)imide , N,N-dimethyl-N,N-dihexyl ammonium bis(trifluoromethanesulfonyl)imide, trimethylheptyl ammonium bis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl-N-propylammonium bis(trifluoromethane Sulfonyl)imide, 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 bis(trifluoromethanesulfonyl)imide, triethylheptylammonium bis(trifluoromethanesulfonyl) ) Imido, N,N-dipropyl-N-methyl-N-ethylammonium bis(trifluoromedanesulfonyl)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(trifluoromethanesulfonyl)imide, trioctylmethylammonium bis(trifluoromethanesulfonyl)imide, N-methyl -N-ethyl-N-propyl-N-pentylammonium bis(trifluoromethanesulfonyl)imide, 1-butylpyridinium (trifluoromethanesulfonyl)trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl)trifluoroacetamide , 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl)trifluoroacetamide, N-ethyl-N-methylmorpholinium thiocyanate, 4-ethyl-4-methylmorpholinium methyl carbonate and the like.

The ionic liquids may be used alone or in combination of two or more.

The content (total amount) of the antistatic component is preferably 1 part by mass or less, more preferably 0.001 to 0.9 part by mass, and even more preferably 100 parts by mass of the (meth)acrylic polymer. Is 0.005 to 0.8 parts by mass, and most preferably 0.01 to 0.7 parts by mass. Within the above range, it is easy to achieve both antistatic property and low contamination property, which is preferable.

<Polyether compound in adhesive layer>
In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains a polyether compound (polyether component), and more preferably contains an organopolysiloxane having an oxyalkylene chain. It is more preferable to contain an organopolysiloxane having an alkylene main chain. It is presumed that the use of the organopolysiloxane reduces the surface free energy of the pressure-sensitive adhesive surface and realizes light release.

(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 above-mentioned organopolysiloxane, a known organopolysiloxane having a polyoxyalkylene main chain can be used as appropriate, but is preferably one represented by the following formula.

(In the formula, 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. May have an alkoxy group or a hydroxyl group, and either R ₁ or R ₂ may have a hydroxyl group, or may have an alkyl group or an alkoxy group. A part of the group or the alkoxy group may be a functional group in which a hetero atom is substituted, and n is an integer of 1 to 300.)

As the organopolysiloxane, one having a siloxane-containing site (siloxane site) as a main chain and an oxyalkylene chain bonded to the end of the main chain is used. It is speculated that by using the organosiloxane having an oxyalkylene chain, the compatibility with the (meth)acrylic polymer, the antistatic component, and the like is balanced, and light release is realized.

Further, as the organopolysiloxane in the present invention, for example, the following constitution can be used. Specifically, R ₁ and/or R ₂ in the formula has an oxyalkylene chain containing a hydrocarbon group having 1 to 6 carbon atoms, and 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. When R ₁ and R ₂ both have an oxyalkylene chain, they may be the same or different.

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

Further, the terminal of the oxyalkylene chain may be an alkoxy group or a hydroxyl group, but among them, an alkoxy group is more preferable. When a separator is attached to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface, the organopolysiloxane having a hydroxyl group at the terminal causes an interaction with the separator, resulting in adhesion (peeling) when peeling the separator from the surface of the pressure-sensitive adhesive layer. Power may increase.

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

Specific examples of the organopolysiloxane having an oxyalkylene chain include commercially available products having trade names of X-22-4952, X-22-4272, X-22-6266, KF-6004, and KF-889. (Above, manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (above, manufactured by Toray Dow Corning), IM22 (manufactured by Asahi Kasei Wacker) 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) an oxyalkylene chain in the main chain, it is also possible to use an organosiloxane having (bonding) an oxyalkylene chain in the side chain, and it is possible to use an oxysilane in the side chain rather than the main chain. It is a more preferred embodiment to use an organosiloxane having an alkylene chain. As the above-mentioned organopolysiloxane, a known organopolysiloxane having a polyoxyalkylene side chain can be used as appropriate, but it is preferably represented by the following formula.

(In the formula, R ₁ is a monovalent organic group, R ₂ , R ₃ and R ₄ are alkylene groups, R ₅ is hydrogen or an organic group, m and n are integers of 0 to 1000, provided that m and n are the same. It does not become 0. a and b are integers from 0 to 100. However, a and b do not become 0 at the same time.)

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

Specific examples of the organosiloxane include, for example, commercial products KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640 and KF. -642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (above, Shin-Etsu Chemical Co., Ltd. (Company) 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-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460 (manufactured by Momentive Performance Materials). , BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (manufactured by Big Chemie Japan), and the like. 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, and more preferably 3 to 14. When the HLB value is out of the above range, the adherence to the adherend deteriorates, which is not preferable.

The pressure-sensitive adhesive composition may contain a polyoxyalkylene chain-containing compound which is a polyether compound (polyether component) containing no organopolysiloxane. By containing the compound in the pressure-sensitive adhesive, a pressure-sensitive adhesive having excellent wettability to the adherend can be obtained.

Specific examples of the polyoxyalkylene chain-containing compound containing no organopolysiloxane include, for example, polyoxyalkylene alkylamines, polyoxyalkylene diamines, polyoxyalkylene fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene alkylphenyls. Nonionic surfactants such as ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl allyl ethers, polyoxyalkylene alkyl phenyl allyl ethers; polyoxyalkylene alkyl ether sulfate ester salts, polyoxyalkylene alkyl ether phosphate ester salts, Anionic surfactants such as polyoxyalkylene alkyl phenyl ether sulfuric acid ester salts and polyoxyalkylene alkyl phenyl ether phosphoric acid ester salts; other cationic surfactants having a polyoxyalkylene chain (polyalkylene oxide chain) and both ions Examples of the surfactant include a polyoxyalkylene chain-containing polyether compound (and a derivative thereof) and a polyoxyalkylene chain-containing acrylic compound (and a derivative thereof). 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 kinds.

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

Further, a specific example of the acrylic compound having a polyoxyalkylene chain is a (meth)acrylate polymer having an oxyalkylene group. As the oxyalkylene group, the number of added oxyalkylene units is preferably 1 to 50, more preferably 2 to 30 from the viewpoint of coordination of the ionic compound when the ionic compound is used as the antistatic component. 2 to 20 is more preferable. Further, the terminal of the oxyalkylene chain may be a hydroxyl group as it is, 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 (meth)acrylic acid alkylene oxide as a monomer unit (component), and specific examples of the (meth)acrylic acid alkylene oxide are Examples of the ethylene glycol group-containing (meth)acrylate include, for example, methoxy-polyethylene glycol (meth)acrylate type such as methoxy-diethylene glycol (meth)acrylate, methoxy-triethylene glycol (meth)acrylate, ethoxy-diethylene glycol ( Butoxy-polyethylene glycol (meth), such as meth-acrylate, ethoxy-polyethylene glycol (meth)acrylate type such as ethoxy-triethylene glycol (meth)acrylate, butoxy-diethylene glycol (meth)acrylate, butoxy-triethylene glycol (meth)acrylate. ) Acrylate type, phenoxy-polyethylene glycol (meth)acrylate type such as phenoxy-diethylene glycol (meth)acrylate, phenoxy-triethylene glycol (meth)acrylate, 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.

Further, as the monomer unit (component), other monomer unit (component) other than the (meth)acrylic acid alkylene oxide can be used. 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) ) Acrylate and/or methacrylate having an alkyl group having 1 to 14 carbon atoms such as acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, and n-tetradecyl (meth)acrylate. Is mentioned.

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- It is also possible to appropriately use acryloylmorpholine, vinyl ethers and the like.

In a more preferable aspect, the polyoxyalkylene chain-containing compound not containing the organopolysiloxane is a compound having a (poly)ethylene oxide chain in at least a part thereof. 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 pressure-sensitive adhesive composition is obtained. To be Above all, when a PPG-PEG-PPG block copolymer is used, a pressure-sensitive adhesive excellent in low stain resistance can be obtained. As the polyethylene oxide chain-containing compound, the mass of the (poly)ethylene oxide chain in the whole polyoxyalkylene chain-containing compound not containing the organopolysiloxane is preferably 5 to 90 mass %, more preferably 5 to 85. %, more preferably 5 to 80% by weight, and most preferably 5 to 75% by weight.

As the molecular weight of the polyoxyalkylene chain-containing compound containing no organopolysiloxane, those having a number average molecular weight (Mn) of 50,000 or less are suitable, preferably 200 to 30,000, more preferably 200 to 10,000, and usually Is preferably 200 to 5,000. If the Mn is too large, the compatibility with the acrylic polymer decreases and the pressure-sensitive adhesive layer tends to whiten. If the Mn is less than 200, contamination with the polyoxyalkylene compound may easily occur. In addition, here, Mn means a polystyrene conversion value obtained by GPC (gel permeation chromatography).

Further, specific examples of the commercially available product of the polyoxyalkylene chain-containing compound containing no organopolysiloxane include, for example, ADEKA Pluronic 17R-4, ADEKA Pluronic 25R-2 (all of which are manufactured by ADEKA Corporation), Latemur PD- 420, Latemur PD-420, Latemur PD-450, Emulgen 120 (manufactured by Kao Corporation), Aqualon HS-10, KH-10, Neugen EA-87, EA-137, EA-157, EA-167, EA-177 ( Above, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and the like.

The content of the polyether compound is preferably 0.01 to 3 parts by mass, more preferably 0.03 to 2 parts by mass, and still more preferably 100 parts by mass of the (meth)acrylic polymer. 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) are easily achieved.

<Crosslinking agent>
In the surface protection film of the present invention, the pressure-sensitive adhesive composition preferably contains a crosslinking agent. In the present invention, the pressure-sensitive adhesive composition is used to form a pressure-sensitive adhesive layer. For example, when the pressure-sensitive adhesive contains the (meth)acrylic polymer, by appropriately adjusting the structural unit, the structural ratio of the (meth)acrylic polymer, the selection and addition ratio of the cross-linking agent and the like, Thus, a surface protective film (adhesive layer) having more excellent heat resistance can be obtained.

As the cross-linking 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, and the use of the isocyanate compound is a preferred embodiment. Further, these compounds may be used alone or in combination of two or more kinds.

Examples of the isocyanate compound include trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), aliphatic polyisocyanates such as dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate (IPDI), 1, Alicyclic isocyanates such as 3-bis(isocyanatomethyl)cyclohexane, 2,4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate (XDI) and other aromatic isocyanates, and the above isocyanate compound Examples of the modified polyisocyanate include an allophanate bond, a biuret bond, an isocyanurate bond, a uretdione bond, a urea bond, a carbodiimide bond, a uretonimine bond, and an oxadiazinetrione bond. For example, as commercially available products, trade name Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (Takeda Pharmaceutical Co., Ltd.), Sumidule T80, Sumidule L, Death Module N3400 (above, Sumika Bayer Urethane) Company), Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (above, manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. These isocyanate compounds may be used alone or in combination of two or more, and it is also possible to use a bifunctional isocyanate compound and a trifunctional or higher functional isocyanate compound in combination. By using a cross-linking agent in combination, both tackiness and repulsion resistance (adhesion to curved surface) can be achieved, and a surface protective film with more excellent adhesion reliability can be obtained.

When the isocyanate compound (bifunctional isocyanate compound and trifunctional or higher functional isocyanate compound) is used in combination, the compounding ratio (mass ratio) of both compounds is [difunctional isocyanate compound]/[3 [Functional isocyanate compound] (mass ratio) is preferably added at 0.1/99.9 to 50/50, more preferably 0.1/99.9 to 20/80, and 0.1/99. 0.99 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. By adjusting and blending within the above range, a pressure-sensitive adhesive layer having excellent adhesiveness and repulsion resistance is obtained, which is a preferable 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-di). Glycidylaminomethyl)cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Co., Inc.) and the like.

Examples of the melamine-based resin include hexamethylolmelamine. Examples of the aziridine derivative include commercial products such as HDU, TAZM, and TAZO (all manufactured by Mutual Yakuhin Co., Ltd.).

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

The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 20 parts by mass, and 0.1 to 15 parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer. It is more preferably contained, further preferably 0.5 to 10 parts by mass, and most preferably 1.0 to 6 parts by mass. When the content is less than 0.01 parts by mass, the cross-linking formation by the cross-linking agent becomes insufficient, the cohesive force of the obtained pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained in some cases. It tends to cause glue residue. On the other hand, when the content exceeds 20 parts by mass, the cohesive force of the polymer is large, the fluidity is lowered, and the adherend (for example, a polarizing plate) is insufficiently wetted, and the adherend and the adhesive are It tends to cause blisters generated between the layer (adhesive composition layer). Furthermore, if the amount of the cross-linking agent is large, the peeling electrification property tends to deteriorate. These cross-linking agents may be used alone or in combination of two or more.

The pressure-sensitive adhesive composition may further contain a crosslinking catalyst for more effectively promoting any of the above-mentioned crosslinking reactions. Examples of the crosslinking catalyst include tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris(acetylacetonato)iron, tris(hexane-2,4-dionato)iron, tris(heptane-2,4-dionate). ) Iron, tris(heptane-3,5-dionato)iron, tris(5-methylhexane-2,4-dionato)iron, tris(octane-2,4-dionato)iron, tris(6-methylheptane-2) ,4-Dionato)iron, tris(2,6-dimethylheptane-3,5-dionato)iron, tris(nonane-2,4-dionato)iron, tris(nonane-4,6-dionato)iron, tris( 2,2,6,6-Tetramethylheptane-3,5-dionato)iron, tris(tridecane-6,8-dionato)iron, tris(1-phenylbutane-1,3-dionato)iron, tris(hexa) Fluoroacetylacetonato)iron, tris(ethylacetoacetate)iron, tris(acetoacetate-n-propyl)iron, tris(isopropylacetoacetate)iron, tris(acetoacetate-n-butyl)iron, tris(acetoacetate-) sec-butyl)iron, tris(acetoacetate-tert-butyl)iron, tris(propionylmethylacetate)iron, tris(propionylethylacetate)iron, tris(propionylacetate-n-propyl)iron, tris(propionylisopropylacetate) 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 Iron-based catalysts such as iron tris(diethyl malonate), trimethoxy iron, 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 of the crosslinking catalyst is not particularly limited, but for example, preferably about 0.0001 to 1 part by mass, and 0.001 to 0.5 part by mass with respect to 100 parts by mass of the (meth)acrylic polymer. The mass part is more preferable. Within the above range, the rate of the crosslinking reaction when forming the pressure-sensitive adhesive layer is high, and the pot life of the pressure-sensitive adhesive composition is long, which is a preferred embodiment.

Further, the pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer has a weight average molecular weight (Mw) of preferably 1,000 or more and less than 30,000, more preferably 1,500 or more and less than 20,000, further preferably 2,000 or more and less than 10,000. The acrylic oligomer is a (meth)acrylic polymer containing an alicyclic structure-containing (meth)acrylic monomer represented by the following general formula as a monomer unit, and when used as an acrylic pressure-sensitive adhesive, It functions as an imparting resin, improves adhesiveness, and is effective in suppressing floating of the surface protection film.
CH ₂ =C(R ¹ )COOR ² [In the above general formula, 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 above general formula include cyclohexyl group, isobornyl group, dicyclopentanyl group, dicyclopentenyl group, adamantyl group, tricyclopentanyl group, tricyclopentenyl group and the like. A hydrogen group etc. can be mentioned. Examples of such (meth)acrylic acid ester having an alicyclic hydrocarbon group include cyclohexyl (meth)acrylate having a cyclohexyl group, isobornyl (meth)acrylate having an isobornyl group, and dicyclopentanyl group. Mention may be made of esters of (meth)acrylic acid such as dicyclopentanyl (meth)acrylate with alicyclic alcohols. Adhesion can be improved by allowing the acrylic oligomer to have an acrylic monomer having a relatively bulky structure as a monomer unit.

The amount of the acrylic oligomer blended is preferably 0.01 to 10 parts by mass, and 0.1 to 7 parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer. Is more preferable, 0.2 to 5 parts by mass is more preferable, and 0.3 to 2 parts by mass is most preferable. By using the compounding amount within the above range, the peeling force (adhesive force) to the adherend can be improved, and it is easy to suppress the floating, which is a preferable mode.

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

<Adhesive layer/surface protection film>
The surface protective film of the present invention is one in which the pressure-sensitive adhesive layer is formed on a substrate, and in that case, the crosslinking of the pressure-sensitive adhesive composition is generally performed after coating the pressure-sensitive adhesive composition. However, it is also possible to transfer the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition after crosslinking onto a substrate or the like.

The method for forming the pressure-sensitive adhesive layer on the base material is not particularly limited, but for example, the pressure-sensitive adhesive layer can be formed by applying the pressure-sensitive adhesive composition (solution) to the base material and drying and removing the polymerization solvent. It is manufactured by forming the above. After that, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer and adjusting the crosslinking reaction. Further, when the pressure-sensitive adhesive composition is applied onto a substrate to prepare a surface protective film, one or more solvents other than a polymerization solvent are added to the pressure-sensitive adhesive composition so that the pressure-sensitive adhesive composition can be uniformly applied onto the substrate. You may add it newly.

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

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

Further, the surface protective film of the present invention preferably has a total thickness of 8 to 300 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 this is a preferred embodiment. In addition, the said total thickness means the total of the thickness including 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 attached to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface, if necessary.

As a material for forming the separator, there are paper and a plastic film, and the plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it is a film capable of protecting 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 united 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 5 to 200 μm, preferably about 10 to 100 μm. It is preferable for it to be in the above-mentioned range since the workability of attaching to the pressure-sensitive adhesive layer and the workability of peeling from the pressure-sensitive adhesive layer are excellent. In the separator, if necessary, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder or the like, coating type, kneading type, vapor deposition type Antistatic treatment such as

The optical member of the present invention is preferably protected by the surface protection film. Since the surface protection film has excellent antistatic properties and stability of peeling electrification voltage over time, it can be used for surface protection applications (surface protection film) during processing, transportation, shipping, etc. It is useful for protecting the surface of. In particular, since it can be used for a plastic product or the like where static electricity is easily generated, it is very useful for antistatic applications in the technical field related to optical/electronic parts in which electrostatic charging is a particularly serious problem.

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

Moreover, 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 device (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.

Sample concentration: 0.2 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 Super H-RC (1)
Detector: Differential refractometer (RI)
The weight average molecular weight was calculated in terms of polystyrene. When the number average molecular weight (Mn) needs to be measured, it was measured in the same manner as the weight average molecular weight.

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

Formula: 1/(Tg+273)=Σ[Wn/(Tgn+273)]
[In the above formula, Tg (°C) is the glass transition temperature of the copolymer, Wn (-) is the mass fraction of each monomer, Tgn (°C) is the glass transition temperature of the homopolymer of each monomer, and n is the Indicates the type. ]
Literature value:
2-ethylhexyl acrylate (2EHA): -70°C
n-Butyl acrylate (BA): -55°C
4-hydroxybutyl acrylate (4HBA): -32°C
2-Hydroxyethyl acrylate (HEA): -15°C
Acrylic acid (AA): 106°C
N-vinylpyrrolidone (NVP): 80°C
Diethylacrylamide (DEAA): 81°C

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

<Measurement of surface resistivity>
The surface resistivity was measured according to JIS-K-6911 using a resistivity meter (HIRESTA UP MCP-HT450 type, manufactured by Mitsubishi Chemical Analytical) in an atmosphere of a temperature of 23° C. and a humidity of 50% RH.
The surface resistivity (Ω/□) measured on the surface of the antistatic layer in the present invention is as follows: light from a fluorescent lamp (400 lux) immediately after coating (initial stage) and at room temperature (23° C.×50% RH). After being left for 1 month (30 days) in an environment where it is directly exposed to light (aging), it is irradiated with ultraviolet rays in a 23°C x 50%RH environment (high pressure mercury lamp, accumulated light intensity: 4000 mJ/cm ² , irradiation time: 30 seconds). After standing still (UV irradiation), under each condition, it is preferably less than 1.0×10 ¹¹ , more preferably less than 5.0×10 ¹⁰ , and even more preferably 1.0. It is less than ×10 ¹⁰ . The surface protective film having a surface resistivity within the above range can be preferably used as a surface protective film used in the processing or transportation of articles such as liquid crystal cells and semiconductor devices that are sensitive to static electricity. The term “immediately after coating” means that the antistatic agent composition (solution) is applied, dried and immediately after forming the antistatic layer. The same applies below.

<Evaluation of printability (print adhesion)>
After printing on the surface of the antistatic layer using the X stamper manufactured by Shachihata under the measurement environment of 23° C.×50% RH, the Nichiban brand name Cellotape (registered trademark) is printed on the print. Adhesion, and then peeling under the conditions of a peeling speed of 30 m/min and a peeling angle of 180 degrees. After that, the surface after peeling is visually observed, and when 50% or more of the printing area is peeled off (poor printability), when 50% or more of the printing area remains without peeling (good printability) ) Was evaluated.

<Measurement of back surface peeling force>
The surface protection film related to each example is cut into a size of 70 mm in width and 100 mm in length, and the product name is Cellotape (registered trademark) (24 mm width, rubber-based adhesive tape) manufactured by Nichiban Co., Ltd. or the product name manufactured by Nitto Denko Corporation. No. 31B (19 mm width, acrylic adhesive tape) was pressure-bonded onto the antistatic layer (back surface layer) of the surface protection film at a pressure of 0.25 MPa and a speed of 0.3 m/min. This was left in an environment of 23° C.×50% RH for 30 minutes, and then peeled at a peeling speed of 0.3 m/min and a peeling angle of 180° in the same environment, and the back surface peeling force (N/24 mm: pair) Cellotape or N/19 mm: vs. No. 31B) was measured.
The back surface peeling force (N/24 mm: to cellophane tape) in the present invention is preferably 1 to 15 N/24 mm, more preferably 2 to 13 N/24 mm, and further preferably 3 to 10 N/. It is 24 mm. Further, the back surface peeling force (N/19 mm: to No. 31B) is preferably 1 to 15 N/19 mm, more preferably 2 to 13 N/19 mm, and further preferably 3 to 10 N/19 mm. Is. If the backside peeling force is out of the above range and the backside peeling force is too light (too low), the pickup tape does not stick to the backside of the surface protective film, and the surface protective film cannot be peeled off. It is not preferable because it becomes difficult to remove the pickup tape from the film.

<Measurement of sliding property (dynamic friction force)>
The surface protection film is cut into a size of 70 mm in width and 100 mm in length, and attached to an acrylic plate (trade name “Acrylite” manufactured by Mitsubishi Rayon Co., Ltd., thickness: 1 mm, width: 70 mm, length: 100 mm) to be a test piece. Prepared. The back surface (surface of the antistatic layer) of this test piece was faced down and placed on a flat PET film held horizontally, and a load of 1.5 kg was placed on the test piece. The test piece on which the load was placed 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 the conditions of a pulling speed of 300 mm/min and a pulling distance of 300 mm. The average value (n=3) of the dynamic friction force (N) was determined.
The slipperiness (dynamic friction force) (N) in the present invention is preferably 2 to 5, more preferably 2 to 4.8 or less, still more preferably 3 to 4.5 or less. is there. Within the above range, when handling an adherend to which a surface protective film is adhered, the back surface of the surface protective film (antistatic layer surface) has good slipperiness and is compatible with the back surface peeling force (adhesive force). And is advantageous in terms of workability.

<Solvent resistance (appearance)>
When the antistatic layer (rear surface layer) of the surface protection film relating to each example was wiped with Bencott (made by Asahi Kasei Fibers Co., Ltd.) soaked in ethanol for 10 reciprocations, the appearance change was visually observed, and the antistatic layer was detached. Was evaluated as x, and the case where the antistatic layer was not detached was evaluated as o.

<Solvent resistance (measurement of surface resistivity)>
The antistatic layer (back surface layer) of the surface protection film relating to each example was wiped 10 times with Bencott (made by Asahi Kasei Fibers Co., Ltd.) impregnated with ethanol, and the resistivity meter (Mitsubishi The surface resistivity was measured using Hiresta UP MCP-HT450 type manufactured by Chemical Analytic Co., Ltd. according to JIS-K-6911.
The surface resistivity (Ω/□) measured on the surface of the antistatic layer in the present invention is preferably less than 1.0×10 ¹¹ and more preferably less than 5.0×10 ¹⁰ . , And more preferably less than 1.0×10 ¹⁰ . The surface protective film having a surface resistivity in the range is, for example, to wipe off stains on the surface protective film, so that even when wiped with ethanol, the surface resistivity can be suppressed to a low level, such as in a liquid crystal cell or a semiconductor device. As described above, it can be suitably used as a surface protective film used in the processing or transportation process of articles that dislike static electricity.

<Measurement of polarizing plate peeling electrification voltage (polarizing plate side)>
After cutting the surface protection film 1 according to each example into a size of 70 mm in width and 130 mm in length and peeling off the release liner, as shown in FIG. 2, the acrylic plate 10 (manufactured by Mitsubishi Rayon Co. On the surface of the polarizing plate 20 (SEG1423DU polarizing plate manufactured by Nitto Denko Corporation, width: 70 mm, length: 100 mm) attached to the product name "Acrylite", thickness: 1 mm, width: 70 mm, length: 100 mm), One end of the surface protective film 1 was projected by 30 mm from the end of the polarizing plate 20 and pressure-bonded with a hand roller.
This sample was left in an environment of 23° C.×50% RH for 1 day and then set at a predetermined position on a sample fixing base 30 having a height of 20 mm. The edge of the surface protective film 1 protruding 30 mm from the polarizing plate 20 was fixed to an automatic winder (not shown) and peeled off at a peeling angle of 150° and a peeling speed of 10 m/min. The potential of the surface of the adherend (polarizing plate) generated at this time is fixed at a position 100 mm in height from the center of the polarizing plate 40 (Kasuga Denki KK, model “KSD-0103”). The "initial polarizing plate peeling electrification voltage" was measured. The measurement was performed in an environment of 23° C. and 50% RH.
In addition, after leaving it for 1 month (30 days) at room temperature (23° C.×50% RH) in the environment where it is directly exposed to the light (400 lux) of the fluorescent lamp, like the “initial polarizing plate peeling electrification voltage”, It was measured as “polarizing plate peeling electrification voltage over time”, and after irradiation with ultraviolet rays (high pressure mercury lamp, accumulated light quantity: 4000 mJ/cm ² , irradiation time: 30 seconds) under an environment of 23° C.×50% RH, Polarizing plate peeling electrification voltage after UV irradiation", and these measurements were performed in an environment of 23°C x 50% RH.
The polarizing plate peeling electrification voltage is a peeling electrification voltage derived from the antistatic layer and the pressure-sensitive adhesive layer constituting the surface protective film of the present invention, and contributes to the antistatic property.
The peeling electrification voltage (kV) of the polarizing plate in the present invention (absolute value, initial value, elapsed time, all after UV irradiation) is preferably 0.6 or less, more preferably 0.5 or less, and further preferably Is 0.4 or less. Within the above range, for example, damage to the liquid crystal driver or the like can be prevented, which is a preferable mode.

<Measurement of peeling electrification voltage on film side (antistatic layer side of surface protection film)>
Similarly to the measurement of the polarizing plate peeling electrification voltage, the surface protective film 1 was peeled from the surface of the polarizing plate 20 at a peeling angle of 150° and a peeling speed of 10 m/min. The potential of the surface protective film 1 generated at this time was measured by a potential measuring device 40 (manufactured by Kasuga Electric Co., model “KSD-0103”) fixed at a height of 100 mm from the center of the surface protective film 1. , "Initial film side peeling electrification voltage" was measured. The measurement was performed in an environment of 23° C. and 50% RH.
In addition, after being left for 1 month (30 days) in an environment where the light of a fluorescent lamp (400 lux) is directly applied at room temperature (23° C.×50% RH), like the “initial film side peeling electrification voltage”, It was measured as the "film side peeling electrification voltage over time", and after irradiation with ultraviolet rays (high pressure mercury lamp, integrated light amount: 4000 mJ/cm ² , irradiation time: 30 seconds) under an environment of 23°C x 50% RH, ""Film side peeling electrification voltage after UV irradiation", and these measurements were performed in an environment of 23°C x 50% RH.
The film-side peeling electrification voltage is a peeling electrification voltage derived from the antistatic layer constituting the surface protective film of the present invention, and contributes to the antistatic property.
The film-side peeling electrification voltage (kV) (absolute value, initial value, elapsed time, after UV irradiation) in the present invention is preferably 0.6 or less, more preferably 0.5 or less, and further preferably Is 0.4 or less. Within the above range, the surface protective film after peeling is not charged and the workability is excellent, which is a preferable embodiment.

<Preparation of Aqueous Dispersion for Antistatic Layer A>
Polyester resin Bayronal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and poly(3,3). 4-ethylenedioxythiophene) (PEDOT)/polystyrenesulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), isocyanurate of hexamethylene diisocyanate blocked with diisopropylamine as a cross-linking agent, and fatty acid as a lubricant Oleamide amide, which is an amide, in a mixed solvent of water/ethanol (1/1), a binder in a solid content of 100 parts by mass, a polyanilinesulfonic acid in a solid content of 80 parts by mass, a PEDOT/PSS in a solid content of 20 parts by mass. Then, 10 parts by mass of the cross-linking agent in solid content and 10 parts by mass of the lubricant in solid content were added, and the mixture was stirred for about 20 minutes and sufficiently mixed. Thus, an aqueous dispersion for antistatic layer A having an NV of about 0.4% was prepared.

<Preparation of Aqueous Dispersion for Antistatic Layer B>
Polyester resin Bayronal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and poly(3,3). 4-ethylenedioxythiophene) (PEDOT)/polystyrene sulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), methoxylated methylol melamine as a cross-linking agent, carbinol-modified poly that is a silicone lubricant as a lubricant. Dimethyl siloxane (BY16-201, manufactured by Dow Corning Toray Co., Ltd.) in a mixed solvent of water/ethanol (1/1), 100 parts by mass of binder in solid content, 45 parts by mass of polyanilinesulfonic acid in solid content, PEDOT/ 30 parts by mass of PSS in solid content, 10 parts by mass of cross-linking agent in solid content, and 10 parts by mass of lubricant in solid content were added, and stirred for about 20 minutes to thoroughly mix. In this way, an aqueous dispersion for antistatic layer B having an NV of about 0.4% was prepared.

<Preparation of Aqueous Dispersion for Antistatic Layer C>
Polyester resin Bayronal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and poly(3,3). 4-ethylenedioxythiophene) (PEDOT)/polystyrenesulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), isocyanurate of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent, and methoxylation Methylol melamine, as a lubricant, a fluorine-containing block copolymer (Modiper F200, manufactured by NOF CORPORATION), which is a fluorine-based lubricant, in a mixed solvent of water/ethanol (1/1), a binder in a solid content of 100 parts by mass, polyanilinesulfonic acid To 25 parts by mass of solid content, 25 parts by mass of PEDOT/PSS in solid content, 10 parts by mass of each cross-linking agent, and 10 parts by mass of solid content of lubricant, and sufficiently stirred for about 20 minutes. Mixed in. Thus, an aqueous dispersion for the antistatic layer C having an NV of about 0.4% was prepared.

<Preparation of aqueous dispersion for antistatic layer D>
Polyester resin Bayronal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and poly(3,3). 4-ethylenedioxythiophene) (PEDOT)/polystyrene sulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), methoxylated methylol melamine as a cross-linking agent, and carnauba wax as a wax-type lubricant as a lubricant. In a mixed solvent of ethanol/ethanol (1/1), 100 parts by mass of binder, 20 parts by mass of polyaniline sulfonic acid in solid content, 80 parts by mass of PEDOT/PSS in solid content, and 10 parts by mass of crosslinking agent in solid content. 20 parts by mass of the lubricant and 20 parts by mass of the solid content were added, and the mixture was stirred for about 20 minutes and sufficiently mixed. In this manner, an aqueous dispersion for antistatic layer D having an NV of about 0.4% was prepared.

<Preparation of aqueous dispersion for antistatic layer K>
Acrylic resin (copolymer of methyl methacrylate/n-butyl acrylate/cyclohexyl methacrylate=6/2/1) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, Mitsubishi Rayon Co., Ltd.) as a conductive polymer. Manufactured by K.K.) and poly(3,4-ethylenedioxythiophene) (PEDOT)/polystyrenesulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), and methoxylated methylol melamine as a crosslinking agent in water/ethanol. In a mixed solvent of (1/1), 100 parts by mass of a binder, 25 parts by mass of a polyanilinesulfonic acid as a solid content, 75 parts by mass of a solid content of PEDOT/PSS, and 10 parts by mass of a crosslinking agent as a solid content. And were added and stirred for about 20 minutes to mix well. Thus, an aqueous dispersion for the antistatic layer K having an NV of about 0.4% was prepared.

<Preparation of Aqueous Dispersions for Antistatic Layers E to J>
Further, based on the content of the formulation in Table 1, water dispersions for antistatic layers E to J were obtained in the same manner as in the method for preparing the water dispersions for antistatic layers A to D.

<Preparation of Aqueous Dispersion for Antistatic Layer L>
Polyester resin Bayronal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and poly(3,3). 4-ethylenedioxythiophene) (PEDOT)/polystyrene sulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), isocyanurate of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent, and fluorine as a lubricant. Fluorine-containing block copolymer (Modiper F200, NOF Corp.), which is a lubricant, is mixed in a water/ethanol (1/1) mixed solvent with 100 parts by mass of binder and 25 parts by mass of polyanilinesulfonic acid as solid content. , PEDOT/PSS in a solid content of 25 parts by mass, a cross-linking agent in a solid content of 10 parts by mass, and a lubricant in a solid content of 170 parts by mass were added, and the mixture was stirred for about 20 minutes and sufficiently mixed. Thus, an aqueous dispersion for the antistatic layer L having an NV of about 0.4% was prepared.

<Preparation of aqueous dispersion for antistatic layer M>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline (weight average molecular weight 15,000, manufactured by Aldrich Co.) as a conductive polymer, and poly(3,4-ethylenedioxy). (Thiophene) (PEDOT)/polystyrene sulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), methoxylated methylol melamine as a cross-linking agent, and carnauba wax as a wax-type lubricant as a lubricant in water/ethanol (1/ In the mixed solvent of 1), 100 parts by mass of binder, 10 parts by mass of polyaniline as solid content, 90 parts by mass of PEDOT/PSS as solid content, 10 parts by mass of crosslinking agent as solid content, and solid content of lubricant as solid content. And 20 parts by mass were added, and the mixture was stirred for about 20 minutes and thoroughly mixed. In this way, an aqueous dispersion for the antistatic layer M having an NV of about 0.4% was prepared.

<Preparation of Acrylic Polymer 1 for Adhesive Layer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 100 parts by mass of 2-ethylhexyl acrylate (2EHA), 4 parts by mass of 2-hydroxyethyl acrylate (HEA), and 2 as a polymerization initiator. , 2'-Azobisisobutyronitrile (0.2 parts by mass) and ethyl acetate (157 parts by mass) were charged, and nitrogen gas was introduced while gently stirring, and polymerization was performed for 6 hours while maintaining the liquid temperature in the flask at about 65°C. The reaction was carried out to prepare an acrylic polymer 1 solution (40% by mass). The acrylic polymer 1 had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of −68° C.

<Preparation of Acrylic Polymer 8 for Adhesive Layer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction 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, N-vinylpyrrolidone (NVP) 0.1 parts by mass, 0.22 parts by mass of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 157 parts by mass of ethyl acetate were charged, and gently. Nitrogen gas was introduced with stirring, the liquid temperature in the flask was maintained at around 65° C., and a polymerization reaction was carried out for 6 hours to prepare an acrylic polymer 8 solution (40 mass %). The acrylic polymer 8 had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of -67°C.

<Preparation of Acrylic Polymers 2-7, 9 and 10 for Adhesive Layer>
Acrylic polymers 2 to 7, 9 and 10 were obtained in the same manner as in the method for preparing the acrylic polymer 1 or 8 for the pressure-sensitive adhesive layer. The components other than the monomer component were blended in the same amount as the acrylic polymer 1.

<Preparation of Acrylic Adhesive 1 Solution for Adhesive Layer>
The acrylic polymer 1 solution (40% by mass) was diluted to 20% by mass with ethyl acetate, and 500 parts by mass of this solution (100 parts by mass of solid content) was added as a crosslinking agent to an isocyanurate body of hexamethylene diisocyanate (Nippon Polyurethane). Industrial Co., Ltd., Coronate HX:C/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) Part) and mixed and stirred to prepare an acrylic pressure-sensitive adhesive 1 solution.

<Preparation of Acrylic Adhesive 10 Solution for Adhesive Layer>
The acrylic polymer 10 solution (40% by mass) was diluted to 20% by mass with ethyl acetate, and 500 parts by mass (100 parts by mass of solid content) of this solution was added to organopolysiloxane (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.). 2 parts by mass (solid content 0.2 parts by mass) diluted with ethyl acetate to 10%, and lithium bis(trifluoromethanesulfone)imide (LiN(CF ₃ SO ₂ ) ₂ as an alkali metal salt as an antistatic component. : LiTFSI, manufactured by Tokyo Kasei Kogyo Co., Ltd.) to a solution of 15% by mass (solid content 0.15 parts by mass) diluted with ethyl acetate, and isocyanurate of hexamethylene diisocyanate as a cross-linking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX:C/HX) 1.0 part by mass (solid content 1.0 part by mass), and 1,3-bis(isocyanatomethyl)cyclohexane (Mitsui Chemicals, Inc., Takenate 600) 0.3 part by mass ( Solid content 0.3 parts by mass), 0.5 parts by mass of iron (III) acetylacetonate (1% by mass ethyl acetate solution) (solid content 0.005 parts by mass) as a cross-linking catalyst, and mixed and stirred. Then, an acrylic adhesive 10 solution was prepared.

<Preparation of Acrylic Adhesives 2-9 Solution for Adhesive Layer>
Acrylic adhesives 2 to 9 solutions were obtained in the same manner as the method for preparing the acrylic adhesives 1 or 10.

<Preparation of solution of urethane-based adhesive 11>
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, and Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000) which is a polyol having three hydroxyl groups 13 2 parts by mass of Sannix GP1000 (manufactured by Sanyo Kasei Co., Mn=1000), which is a polyol having three hydroxyl groups, and 18 parts by mass of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co.) as a crosslinking agent. As a catalyst, 0.04 parts by mass of iron (III) acetylacetonate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 210 parts by mass of ethyl acetate as a diluting solvent were mixed to obtain a urethane adhesive 11 solution. In addition, as a raw material of the urethane-based pressure-sensitive adhesive solution, all except the solvent are raw materials having a concentration of 100%.

<Preparation of 12 solutions of urethane adhesive>
As a catalyst, a urethane-based adhesive 12 solution was obtained in the same manner as the urethane-based adhesive 11 solution, except that 0.08 parts by mass of a tin-based catalyst dibutyltin dilaurate was used.

<Preparation of 13 solutions of urethane adhesive>
As the wettability improver, 30 parts by mass of isopropyl myristate (Exepar IPM, manufactured by Kao) and 0.5 part by mass of Irganox 1010 (manufactured by BASF) as an antioxidant were further added, except that the urethane adhesive 11 solution was added. A urethane-based pressure-sensitive adhesive 13 solution was obtained in the same manner as in.

<Preparation of Urethane Adhesive 14 Solution>
Polyether compound (KF-6004, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 part by mass, antistatic component 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI, manufactured by Daiichi Kogyo Co., Ltd.) ) A urethane adhesive 14 solution was obtained in the same manner as the urethane adhesive 13 solution except that 0.5 part by mass was further added.

<Preparation of Silicone Adhesive 15 Solution>
As a silicone-based 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.) 0.5 parts by mass) and 100 parts by mass of toluene as a solvent were mixed to obtain a silicone adhesive 15 solution.

<Preparation of Silicone Adhesive 16 Solution (R)>
0.2 parts by mass of a polyether compound (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.), lithium bis(trifluoromethanesulfonyl)imide (LiN(CF ₃ SO ₂ ) ₂ : LiTFSI, which is an antistatic component, Tokyo Chemical Industry Co., Ltd. Silicone pressure sensitive adhesive 16 solution was obtained in the same manner as in the above silicone pressure sensitive adhesive 15 solution, except that 0.3 part by mass was further added.

<Preparation of substrate with antistatic layer>
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 was coated with the aqueous dispersion of any of the antistatic layers (A) to (K) to give a thickness after drying. It was applied so as to have a thickness of 20, 30, 45 nm. The coated product was heated at 130° C. for 1 minute and dried to prepare a base material with an antistatic layer having an antistatic layer on the first surface of the PET film.

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

<Example 11>
<Production of surface protection film>
The urethane adhesive 11 solution is applied to the surface of the base material having the antistatic layer (base material with antistatic layer) opposite to the antistatic layer and heated at 130° C. for 1 minute to give a thickness of 10 μm. The adhesive layer of was formed. Next, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which is a silicone-treated separator on one side, was attached to the surface of the pressure-sensitive adhesive layer to prepare a surface protective film.

<Example 15>
<Production of surface protection film>
The silicone adhesive 15 solution is applied to the surface of the base material having the antistatic layer (base material with antistatic layer) opposite to the antistatic layer and heated at 150° C. for 1 minute to give a thickness of 10 μm. The adhesive layer of was formed. Next, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which is a silicone-treated separator on one side, was attached to the surface of the pressure-sensitive adhesive layer to prepare a surface protective film.

<Examples 2 to 10, Example 17, Example 18, and Comparative Examples 1 to 5>
A surface protective film was produced in the same manner as in Example 1 based on the formulation contents in Tables 1 to 3.

<Examples 12 to 14>
A surface protective film was produced in the same manner as in Example 11 based on the formulation contents in Tables 1 and 4.

<Example 16>
A surface protection film was produced in the same manner as in Example 15 based on the formulation contents in Tables 1 and 5.

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

The abbreviations in Tables 2 and 3 will be described below. Abbreviations in the other tables are based on the examples.
[Monomer component]
2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate 4HBA: 4-hydroxybutyl acrylate HEA: 2-hydroxyethyl acrylate AA: acrylic acid NVP: N-vinylpyrrolidone DEAA: diethyl acrylamide

[Polyether compound]
KF353: Organopolysiloxane having oxyalkylene chain (HLB value: 10) (Shin-Etsu Chemical Co., Ltd., trade name: KF-353)
KF6004: Organopolysiloxane having oxyalkylene chain (HLB value: 9) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-6004)
HS10: Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "Aqualon HS-10" (anionic surfactant)
EA137: Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "Neugen EA-137" (nonionic surfactant)

[Antistatic component (ionic compound)]
LITFSI: Lithium bis(trifluoromethanesulfonyl)imide (alkali metal salt, manufactured by Tokyo Chemical Industry Co., Ltd.) (100% active ingredient)
BMPTFSI: 1-Butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide (ionic liquid, manufactured by Sigma-Aldrich, liquid at 25° C.) (100% active ingredient)
EMIFSI: Ionic liquid: 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (ionic liquid, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) (100% active ingredient)

[Crosslinking agent]
C/HX: hexamethylene diisocyanate isocyanurate (manufactured by Nippon Polyurethane Company, trade name: Coronate HX) (100% active ingredient)
C/L: trimethylolpropane/tolylene diisocyanate (Nippon Polyurethane Industry Co., Ltd., trade name: Coronate L) (75% active ingredient)
Takenate 600: 1,3-bis(isocyanatomethyl)cyclohexane (Mitsui Chemicals, Inc., trade name: Takenate 600) (100% active ingredient)

[Crosslinking catalyst]
Sn: dibutyltin dilaurate (dibutyltin dilaurate) (manufactured by Tokyo Chemical Industry Co., Ltd.)
Fe: tris(acetylacetonato)iron (iron(III) acetylacetonate) (manufactured by Tokyo Chemical Industry Co., Ltd.)

注）表中の「＞１Ｅ＋１３」とは１０の１３乗を超えることを示す。

Note) “>1E+13” in the table means that it exceeds 10 to the 13th power.

From Table 6, in all of the examples, excellent surface resistivity, film-side peeling electrification voltage, and the like, and in the case of blending an ionic compound which is an antistatic agent and a polyether compound, a polarizing plate peeling electrification voltage It is also confirmed that when the antistatic layer contains a lubricant, the slipperiness is excellent, and when the adhesive layer contains an antistatic component, the polarizing plate peeling voltage is also excellent. It was Further, it was confirmed that the example using the polyester resin was excellent in solvent resistance as compared with the example 17 using the acrylic resin as the binder.

On the other hand, from Table 6, in Comparative Examples 1 to 5, since the conductive polymer constituting the antistatic layer was not blended in a desired ratio, the surface resistivity and the film-side peeling electrification voltage with time and after UV irradiation were changed. It was confirmed that it was inferior to the example. Particularly in Comparative Example 5, since the externally doped type polyaniline was used in place of the self-doped type polyaniline sulfonic acid having conductivity by itself, polythiophenes (PEDOT) to polyanions (PSS) (corresponding to a dopant) were used over time. It was confirmed that the surface resistivity with time was inferior to that of the example.

The surface protection film disclosed herein protects an optical member used as a constituent element of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescence (EL) display or the like during manufacturing or transportation. It is suitable as a surface protection film for In particular, a surface protective film (optical surface) applied to optical members such as a polarizing plate (polarizing film) for liquid crystal display panels, a wave plate, a retardation plate, an optical compensation film, a brightness enhancement film, a light diffusion sheet, and a reflection sheet. It is useful as a protective film).

1: Surface protection 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 (10)

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 antistatic layer is formed from a polyanilinesulfonic acid as a conductive polymer component, and a polythiophene doped with polyanions, and an antistatic agent composition containing a polyester resin as a binder. ,
The surface protection film, wherein the mixing ratio (mass ratio) of the polyanilinesulfonic acid and the polythiophenes doped with the polyanions is 90:10 to 10:90. The surface protection film according to claim 1, wherein the polythiophenes are poly(3,4-ethylenedioxythiophene) (PEDOT). The surface protection film according to claim 1, wherein the polyanions are polystyrene sulfonic acid (PSS). The antistatic agent composition, as a crosslinking agent, a melamine crosslinking agent, and / or a surface protective film according to any one of claims 1 to 3, characterized in that it comprises an isocyanate crosslinking agent. The antistatic agent composition contains, as a lubricant, at least one selected from the group consisting of fatty acid amides, fatty acid esters, silicone lubricants, fluorine lubricants, and wax lubricants. The surface protection film according to any one of to 4 . Surface protective film according to any one of claims 1 to 5, wherein the substrate is, which is a polyester film. The pressure-sensitive adhesive composition, an acrylic adhesive, a urethane adhesive, and to any one of claims 1 to 6, characterized in that it contains at least one member selected from the group consisting of silicone adhesive The surface protection film described. Surface protective film according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive composition, characterized by containing a polyether compound. Surface protective film according to any one of claims 1 to 8, wherein the pressure-sensitive adhesive composition, characterized in that it contains an antistatic component. Optical members, characterized in that it is protected by a surface protective film according to any one of claims 1-9.

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