WO2016114256A1

WO2016114256A1 - Surface protection film, and optical member

Info

Publication number: WO2016114256A1
Application number: PCT/JP2016/050667
Authority: WO
Inventors: 賢一片岡; 奈津子渡部; 数馬三井; 天野　立巳
Original assignee: 日東電工株式会社
Priority date: 2015-01-16
Filing date: 2016-01-12
Publication date: 2016-07-21

Abstract

Provided are a surface protection film with which it is possible to achieve anti-static properties and temporal stability in peeling electrostatic potential, and an optical member. The surface protection film of the present invention is provided with a base material having a first surface and a second surface, an anti-static layer provided on the first surface of the base material, and an adhesive layer formed from an adhesive composition on the second surface of the base material, wherein the surface protection film is characterized in that: the anti-static layer is formed from an anti-static composition containing polyaniline sulfonic acid and polythiophenes doped by polyanions as conductive polymer components, and a binder; and the mixture ratio (mass ratio) of the polyaniline sulfonic acid and the polythiophenes doped by polyanions is 90:10-10:90.

Description

Surface protective film and optical member

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

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

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

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

In recent years, PEDOT (poly (3,4-ethylenedioxythiophene) / PSS (polystyrene sulfonic acid) (polythiophene type) is used as a conductive polymer used to impart an antistatic function to the surface layer of the surface protective film. However, when an antistatic layer is formed using the conductive polymer, PSS (corresponding to a dopant) is desorbed from PEDOT as time passes, and the surface There may be an increase in resistivity and peeling voltage, and there may be problems such as an increase in surface resistivity (deterioration) due to oxidation degradation and photodegradation. When this 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, the present invention has been made in view of the above circumstances, and as a result of intensive research, it is an object of the present invention to provide a surface protective film and an optical member that can achieve antistatic properties and stability over time of peeling voltage.

That is, the surface protective film of the present invention has a substrate having a first surface and a second surface, an antistatic layer provided on the first surface of the substrate, and an adhesive to the second surface of the substrate. A polythiophene doped with polyaniline sulfonic acid and polyanions as a conductive polymer component, and a surface protective film comprising a pressure-sensitive adhesive layer formed from an adhesive composition, and The blend ratio (mass ratio) of the polythiophene doped with the polyaniline sulfonic acid and the polyanions is 90:10 to 10:90, formed from an antistatic composition containing a binder. It is characterized by being.

In the surface protective film of the present invention, the polythiophene is preferably poly (3,4-ethylenedioxythiophene) (PEDOT).

In the surface protective 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, the antistatic composition preferably contains a melamine-based crosslinking agent and / or an isocyanate-based crosslinking agent as a crosslinking agent.

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

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

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

In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains 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 protective 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 of an antistatic agent composition containing a specific conductive polymer component in a specific ratio. Accordingly, it is possible to provide a surface protective film and an optical member that can achieve antistatic properties based on the antistatic layer and stability over time of the peeling band voltage, and are useful.

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

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

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

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

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

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

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

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

Various additives such as antioxidants, ultraviolet absorbers, plasticizers, colorants (pigments, dyes, etc.), antistatic agents, antiblocking agents, etc., are blended in the resin material constituting the base material as necessary. May be. For example, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer are applied to the first surface of the polyester film (the surface on which the antistatic layer is provided). The surface treatment may be performed. Such a surface treatment can be, for example, a treatment for enhancing the adhesion between the substrate and the antistatic layer. Surface treatment in which polar groups such as hydroxyl groups are introduced on the surface of the substrate can be preferably employed. Moreover, the surface treatment similar to the above may be given to the 2nd surface (surface by which the adhesive layer is formed) of a base material. Such a surface treatment may be a treatment for enhancing the adhesion between the film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

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

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

<Antistatic layer (topcoat layer)>
The surface protective film of the present invention is provided on a base material having a first surface (back surface) and a second surface (surface opposite to the first surface), and the first surface (back surface) of the base material. A surface protective film comprising an antistatic layer and an adhesive layer formed of an adhesive composition on the second surface of the substrate, wherein the antistatic layer is a polyaniline sulfone as a conductive polymer component. A polythiophene doped with an acid and a polyanion, and an antistatic agent composition containing a binder, wherein the polythiophene is doped with the polyaniline sulfonic acid and the polyonion. The blending ratio (mass ratio) is 90:10 to 10:90. When the surface protective film has an antistatic layer (topcoat layer), the antistatic property of the surface protective film and the stability over time of the stripping voltage are improved, which is a preferred embodiment. In particular, the polyaniline sulfonic acid and the polythiophenes doped with the polyions are blended within the above range, so that the polyaniline sulfonic acids alone or the polythiophenes doped with the polyions can be used alone. Compared with the case where it mix | blends, although the time-dependent stability of antistatic property improves, the following reasons are estimated. Polythiophenes doped in polyanions are complexed by anion groups of polyanions coordinated to polythiophenes, and the conduction mechanism is the intramolecular conductivity of polythiophenes occurring in the complex, polythiophenes The intermolecular conduction and the conduction between complex structures are known. Here, the conduction between the complex structures is a rate-determining process because the intermolecular distance is large. Generally, by using polyaniline sulfonic acid, which is a polymer higher than polythiophenes, the polyaniline sulfonic acid connects between the complexes composed of polythiophenes and polyanions, and itself has conductivity. It is presumed that the antistatic property is improved and the stability is increased, and by using these together, it becomes very useful as a surface protective film.

<Conductive polymer>
The antistatic layer contains polyanilinesulfonic acid and polythiophenes doped with polyions as conductive polymer components. Compared to the combination of each of the conductive polymers, the polyaniline sulfonic acid is responsible for the conduction between the polythiophene / polyanion complex structures, so the conductivity is increased and the antistatic layer is based on an antistatic layer. And the peeling voltage over time can be stabilized, which is useful.

The conductive polymer is preferably used in an amount of 1 to 1000 parts by weight, more preferably 5 to 750 parts by weight, even more preferably 100 parts by weight of the binder contained in the antistatic layer (topcoat 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. If the amount of the conductive polymer used is too large, the adhesion of the antistatic layer to the substrate may be reduced, or the transparency may be reduced. There is a risk of lowering, which is not preferable.

The polyaniline sulfonic acid used as the conductive polymer component preferably has a polystyrene equivalent weight average molecular weight (Mw) of 5 × 10 ⁵ or less, more preferably 3 × 10 ⁵ or less. In addition, the weight average molecular weight of these conductive polymers is usually preferably 1 × 10 ³ or more, and more preferably 5 × 10 ³ or more.

Examples of commercial products of the polyaniline sulfonic acid include a 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-diheptyloxy) Thiophene), poly (3,4-dioctyloxythiophene), poly (3,4-di Siloxythiophene), poly (3,4-didodecyloxythiophene), poly (3,4-ethylenedioxythiophene), poly (3,4-propylenedioxythiophene), poly (3,4-butenedioxy) Thiophene), poly (3-methyl-4-methoxythiophene), poly (3-methyl-4-ethoxythiophene), poly (3-carboxythiophene, poly (3-methyl-4-carboxythiophene), poly (3- Methyl-4-carboxyethylthiophene) and poly (3-methyl-4-carboxybutylthiophene), which may be used alone or in combination of two or more. From the viewpoint of properties, poly (3,4-ethylenedioxythiophene) (PEDOT) is preferable.

The polythiophene has a polymerization degree of preferably 2 to 1000, more preferably 5 to 100. It is preferable for it to be within the above range because of its excellent conductivity.

The polyanion is a polymer of a structural unit having an anion group, and acts as a dopant for the polythiophene. 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), polymethallyloxybenzene sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly (2-acrylamide) -2-methylpropanecarboxylic acid), polyisoprene carboxylic acid, polyacrylic acid, polysulfonated phenylacetylene and the like. These homopolymers may be sufficient and 2 or more types of copolymers may be sufficient. Of these, polystyrenesulfonic acid (PSS) is preferable from the viewpoint of improving the conductivity and dispersibility of polythiophenes.

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

Examples of commercially available polythiophenes doped with the polyanions include poly (3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS) trade name “Bytron P” manufactured by BAYER, Shin-Etsu. Examples include the product name “Sepluzida” manufactured by Polymer Co., Ltd. and the product name “Verazol” manufactured by Soken Chemical Co.

The antistatic agent composition has a blending ratio (mass ratio) of the polyaniline sulfonic acid and the polythiophenes doped with the polyanions (the polyaniline sulfonic acid: the polythiophenes doped with the polyanions)). 90:10 to 10:90, preferably 85:15 to 15:85, and more preferably 80:20 to 20:80. If it is in the said range, surface resistivity can be suppressed and it is excellent in especially the stability of surface resistivity over time, and becomes a preferred embodiment. In the case of the polyaniline sulfonic acid alone, since the initial conductivity is low, an increase in the peel voltage and surface resistivity with time is likely to occur, and in the case of the polythiophene alone doped with the polyanions, the initial Although the conductivity is high, polyanions (corresponding to dopants) are more likely to be detached from polythiophenes over time, which is not preferable because peeling voltage and surface resistivity with time are likely to increase.

<Binder>
The antistatic layer contains a binder in order to impart solvent resistance, mechanical strength, and thermal stability. Binders include acrylic resin, acrylic urethane resin, acrylic styrene resin, acrylic silicone resin, silicone resin, fluorine resin, styrene resin, polyester resin, alkyd resin, polyurethane resin, amide resin, polyolefin resin, polysilazane resin, and their modifications. Or a copolymer resin is mentioned. The above resins may be used alone or in combination of two or more. Among the above resins, a polyester resin is preferably used because it is particularly excellent in solvent resistance.

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

Examples of compounds that can be employed as the polyvalent carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±) -malic acid, meso -Tartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid, methyladipic acid, dimethyl Adipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6-tetramethylsuberic acid, azelaic acid, sebacic acid, perfluoro Sebacic acid, brassic acid, dodecyl dica Aliphatic dicarboxylic acids such as boronic acid, tridecyl dicarboxylic acid, tetradecyl dicarboxylic acid; cycloalkyl dicarboxylic acids (for example, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4- (2- Alicyclic dicarboxylic acids such as norbornene) dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantane dicarboxylic acid, spiroheptane dicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, methylisophthalic acid, Dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methyl terephthalic acid, dimethyl terephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorenedicarboxylic acid, anthracenedica Rubonic acid, biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4 "-p-terephenylenedicarboxylic acid, 4,4" -p-quarelphenyldicarboxylic 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) dipropion Aromatic dicarboxylic acids such as acids, 4,4′-bibenzyldiacetic acid, 3,3 ′ (4,4′-bibenzyl) dipropionic acid, oxydi-p-phenylenediacetic acid; An acid anhydride of any of the polyvalent carboxylic acids described above Tell (eg alkyl esters). It can be a monoester, a diester or the like. ); Acid halides corresponding to any of the polyvalent carboxylic acids described above (for example, dicarboxylic acid chloride); and the like.

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

On the other hand, examples of compounds that can be employed as the polyhydric alcohol component include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. Neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl- Diols such as 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A and bisphenol A Is mentioned. Other examples include alkylene oxide adducts (for example, ethylene oxide adducts, propylene oxide adducts, etc.) of these compounds.

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

Examples of the polyester resin include trade names Vylonal MD-1100, MD-1200, MD-1245, MD-1335, MD-1480, MD-1500, MD-1930, MD-1985, MD-2000 manufactured by Toyobo Co., Ltd. Trade names plus coats 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-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 (topcoat layer) is a resin other than a polyester resin (for example, acrylic) as a binder as long as the performance of the surface protective film disclosed herein (for example, performance such as antistatic properties) is not significantly impaired. Resin, acrylic urethane resin, acrylic styrene resin, acrylic silicone resin, silicone resin, fluorine resin, styrene resin, alkyd resin, polyurethane resin, amide resin, polyolefin resin, polysilazane resin, etc., and their modified or copolymer resins 1 type, or 2 or more types of resins). A preferred embodiment of the technology disclosed herein is a case where the binder of the antistatic layer is substantially composed only of a polyester resin. For example, an antistatic layer in which the proportion of the polyester resin in the binder is 98 to 100% by mass is preferable. The proportion of the binder in the whole antistatic layer can be, for example, 50 to 95% by mass, and usually 60 to 90% by mass is appropriate.

<Lubricant>
The antistatic layer (top coat layer) in the technique disclosed herein comprises at least one selected from the group consisting of fatty acid amides, fatty acid esters, silicone-based lubricants, fluorine-based lubricants, and wax-based lubricants as lubricants. Use is a preferred embodiment. By using the lubricant, the surface of the antistatic layer is not subjected to a further release treatment (for example, a treatment in which a known release treatment agent such as a silicone release agent or a long-chain alkyl release agent is applied and dried). In this case, an antistatic layer (topcoat layer) having both sufficient slipperiness and print adhesion can be obtained, which can be a preferable embodiment. Thus, the aspect in which the surface of the antistatic layer is not further peeled can prevent whitening due to the peeling treatment agent (for example, whitening due to storage under heating and humidification conditions). This is preferable. It is also advantageous from the viewpoint of solvent resistance.

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

Specific examples of the fatty acid ester include polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, monoglyceride behenate, cetyl 2-ethylhexanoate, isopropyl myristate, palmitic acid Isopropyl acid, cholesteryl isostearate, lauryl methacrylate, coconut fatty acid methyl, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol Tetrapalmitate, stearyl stearate, isotridecyl stearate, 2-ethylhexanoic acid triglyceride Butyl laurate, and the like octyl oleate. 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, carboxyl modified polydimethyl. Siloxane, methyl hydrogen silicone, methacrylic modified polydimethylsiloxane, phenol modified polydimethylsiloxane, silanol modified polydimethylsiloxane, aralkyl modified polydimethylsiloxane, fluoroalkyl modified polydimethylsiloxane, long chain alkyl modified polydimethylsiloxane, higher fatty acid modified ester Modified polydimethylsiloxane, higher fatty acid amide modified polydimethylsiloxane, phenyl modified poly Dimethyl siloxane. 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, polyether polymer having a fluorinated alkyl group, and the like. These lubricants may be used alone or in combination of two or more.

Specific examples of the wax-based lubricant include petroleum wax (paraffin wax, etc.), plant wax (carnauba wax, etc.), mineral wax (montan wax, etc.), higher fatty acid (serotic acid, etc.), and neutral fat (palmitin). And various waxes such as acid triglyceride). These lubricants may be used alone or in combination of two or more.

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

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

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

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

The antistatic layer in the technique disclosed herein may contain other antistatic components, antioxidants, colorants (pigments, dyes, etc.), fluidity modifiers (thixotropic agents, thickeners, etc.), if necessary. It may contain additives such as film-forming aids, surfactants (such as antifoaming agents), and preservatives. Moreover, it is also possible to contain a glycidyl compound, a polar solvent, a polyhydric aliphatic alcohol, a lactam compound, etc. as a 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 an appropriate solvent (water or the like). A coating material for forming, an antistatic agent composition) can be suitably formed by a technique including applying to a substrate. For example, a method of applying the coating material to the first surface of the substrate and drying it, and performing a curing treatment (heat treatment, ultraviolet treatment, etc.) as necessary can be preferably employed. The NV (nonvolatile content) of the coating material can be, for example, 5% by mass or less (typically 0.05 to 5% by mass), and usually 1% by mass or less (typically 0.10 to 10%). 1 mass%) is appropriate. In the case of forming an antistatic layer having a small thickness, it is preferable that the NV of the coating material is, for example, 0.05 to 0.50 mass% (for example, 0.10 to 0.40 mass%). Thus, a more uniform antistatic layer can be formed by using a low NV coating material.

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

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

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-aminopropyl Amine compounds such as limethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, hydrochlorides of primary amines such as monomethylamine, monoethylamine, stearylamine, dimethylamine, diethylamine, Quaternary ammonium salts such as distearylamine and other secondary amine hydrochlorides, tribasic amine hydrochlorides such as trimethylamine, triethylamine and stearyldimethylamine, stearyltrimethylammonium chloride, distearyldimethylammonium chloride and stearyldimethylbenzylammonium chloride , Hydrochlorides of ethanolamines such as monoethanolamine, diethanolamine and triethanolamine, polyethylene such as ethylenediamine and diethylenetriamine Hydrochloride salt of Riamin acids and the like.

Specific examples of the cationic emulsifier include alkyl ammonium salts, alkyl amide betaines, and alkyl dimethyl amine oxides.

Specific examples of the basic resin include those made of a polyester-based, acrylic-based, or urethane-based polymer copolymer, and those 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 dispersion effect may be reduced. Even if the weight average molecular weight is greater than 1,000,000, an aggregating action may occur. .

The amine value of the basic resin is preferably 5 to 200 mgKOH / g. If it is less than 5 mgKOH / g, the interaction with polyanions doped in 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 may be reduced and the dispersion effect may be insufficient as compared with the affinity part for polyanions doped in polythiophenes.

Examples of the basic resin include Solsperse 17000, Solsperse 20000, Solsperse 24000, Solsperse 32000 (manufactured by Geneca Corporation), Disperbyk-160, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk-170, Disperbyk-170, (By Big Chemie), Addisper PB711, Addisper PB821, Addisper PB822, Addisper PB824 (Ajinomoto Co., Inc.), Epomin 006, Epomin 012, Epomin 018 (Nippon Shokubai Co., Ltd.), EFKA4046, EFKA4300, EFKA4330, EFKA4330, EFKA4330 Made) Ron DA-400 N (manufactured by Kusumoto Chemicals Chemical Co.), etc., and can be used alone or in combination. In particular, Addisper PB821, Addisper PB822, and Addisper 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 weight to 100,000 parts by weight, preferably 10 parts by weight to 10,000 parts by weight with respect to a total of 100 parts by weight of the polythiophenes and the polyanions. It is preferable to be added.

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

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

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

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

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

When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, the (meth) acrylic polymer constituting the acrylic pressure-sensitive adhesive has an alkyl group having 1 to 14 carbon atoms as a raw material monomer constituting the acrylic pressure-sensitive adhesive (meta ) Acrylic monomers can be used as 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 strength) to the adherend (protected body) to be low and light peeling. A surface protective film excellent in removability and removability can be obtained. In the present invention, the (meth) acrylic polymer refers to an acrylic polymer and / or a methacrylic polymer, and the (meth) acrylate refers to acrylate and / or 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, etc. It is done.

Among these, the surface protective film of the present invention includes hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl. 6 to 14 carbon atoms such as (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. (Meth) acrylic monomers having an alkyl group are preferred. In particular, by using a (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the peel force (adhesive force) to the adherend low and has excellent removability. It 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, it is 60% by mass or more, more preferably 70 to 99% by mass, and most preferably 80 to 98% by mass. If it is less than 50% by mass, the appropriate wettability of the pressure-sensitive adhesive composition and the cohesive strength of the pressure-sensitive adhesive layer will be inferior, which is not preferable.

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

By using the hydroxyl group-containing (meth) acrylic monomer, it becomes easy to control the crosslinking of the pressure-sensitive adhesive composition, and as a result, balance between improvement of wettability by flow and reduction of peeling force (adhesive strength) in peeling. It becomes easier to control. Furthermore, unlike carboxyl groups and sulfonate groups that can generally act as crosslinking sites, hydroxyl groups have moderate interactions with ionic compounds and polyether compounds that are antistatic components (antistatic agents). Also, it can be suitably used in terms of antistatic properties.

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 having 4 or more carbon atoms in the alkyl group because light release at high speed peeling is easy.

Preferably, the hydroxyl group-containing (meth) acrylic monomer is contained in an amount of 25 parts by mass or less, more preferably 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. 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 resulting pressure-sensitive adhesive layer can be easily controlled, which is preferable.

As another polymerizable monomer component, the glass transition temperature and release of the (meth) acrylic polymer should be adjusted so that the Tg is 0 ° C. or lower (usually −100 ° C. or higher) because the adhesive performance is easily balanced. A polymerizable monomer or the like for adjusting the property can be used as long as the effects of the present invention are not impaired.

As the polymerizable monomer other than the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer, and 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, carboxylpentyl (meth) acrylate, and the like.

The carboxyl group-containing (meth) acrylic monomer is preferably 5 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. More preferably, it is 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 the amount 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 as an antistatic component (antistatic agent) is blended, An acid functional group such as a carboxyl group interacts with the prevention component, etc., which impedes ion conduction, lowers the conductivity efficiency, and may not provide sufficient antistatic properties.

Further, the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the hydroxyl group-containing (meth) acrylic monomer, and the carboxyl group-containing (meth) acrylic used in the (meth) acrylic polymer. Any other polymerizable monomer other than the monomer can be used without particular limitation as long as it does not impair the characteristics of the present invention. For example, cohesive strength / heat resistance improving components such as cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine In addition, a component having a functional group functioning as an improvement in peeling strength (adhesive strength) such as a vinyl ether monomer or as a crosslinking base point can be appropriately used. Among these, 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. Use of a nitrogen-containing monomer is useful because it can ensure an appropriate peeling force (adhesive strength) that does not cause floating or peeling, and can provide a surface protective film having excellent shearing force. These polymerizable monomers can be used alone 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, and N, N-diethyl. Examples include methacrylamide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, and diacetone acrylamide.

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

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

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

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

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

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

In the present invention, the polymerizable monomer other than the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the hydroxyl group-containing (meth) acrylic monomer, and the carboxyl group-containing (meth) acrylic monomer, The amount is preferably 0 to 40 parts by mass, and more preferably 0 to 30 parts by mass with respect to 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. By using the other polymerizable monomer within the above range, when using an ionic compound or a polyether compound as an antistatic component, a good interaction and a good removability are appropriately adjusted. 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 the oxyalkylene unit of the alkylene oxide group-containing reactive monomer is 1 to 40 from the viewpoint of compatibility with an ionic compound as an antistatic component or a polyether compound. It is preferably 3 to 40, more preferably 4 to 35, and particularly preferably 5 to 30. When the average added mole number is 1 or more, the effect of reducing the contamination of the adherend (protected body) tends to be obtained efficiently. Further, when the average added mole number is larger than 40, it is preferable because the interaction with the ionic compound or the polyether compound is large and the viscosity of the pressure-sensitive adhesive composition tends to increase to make coating difficult. Absent. Note that the terminal of the oxyalkylene chain may be a hydroxyl group or may be substituted with another functional group.

The alkylene oxide group-containing reactive monomer may be used alone or in combination of two or more, but the total content is the total amount of monomer components of the (meth) acrylic polymer. The content is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, still more preferably 4% by mass or less, and 3% by mass or less. Particularly preferred is 1% by mass or less. If the content of the alkylene oxide group-containing reactive monomer exceeds 20% by mass, the interaction with the ionic compound or the polyether compound is increased, ionic conduction is hindered, and the antistatic property is decreased. 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, such as an oxymethylene group, an oxyethylene group, an oxypropylene group, and an oxybutylene group. It is done. The hydrocarbon group of the oxyalkylene chain may be linear or branched.

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, compatibility between the base polymer and the ionic compound or the polyether compound as an antistatic component is improved, and the deposition is performed. Bleed to the body is suitably suppressed, and a low-staining adhesive composition is obtained.

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

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

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

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

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

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

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

When using a silicone-based pressure-sensitive adhesive for the pressure-sensitive adhesive layer, any appropriate silicone-based pressure-sensitive adhesive can be adopted. As such a silicone-based pressure-sensitive adhesive, one obtained by blending or agglomerating a silicone resin (silicone-based polymer, silicone component) can be preferably used.

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

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

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

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

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

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

As 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. An ionic liquid having these cations provides a further excellent antistatic ability.

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

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

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

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

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

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

Specific examples include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl. -3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidi Cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium Cation, 1-ethyl-1-propylpyrrolidi Cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium Cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation, pyrrolidinium-2-one cation, 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpi Peridinium cation, 1-methyl-1-pentylpiperidinium cation 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, Propyl-1-butylpiperidinium cation, 1,1-dibutylpiperidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethyl Carbazole cation, N-ethyl-N-methylmorpholinium cation, etc. I can get lost.

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

Specific examples include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-helium Xyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazole Rium 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-methyl Xylethyl) -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 On, such as 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation.

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

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

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

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

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

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

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

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

In addition, the said ionic liquid may be used independently, and 2 or more types may be mixed and used for it.

Further, 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 more preferably 100 parts by mass of the (meth) acrylic polymer. Is 0.005 to 0.8 parts by mass, most preferably 0.01 to 0.7 parts by mass. It is preferable for it to be in the above-mentioned range since it is easy to achieve both antistatic properties and low contamination.

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

As the organopolysiloxane, a known organopolysiloxane having a polyoxyalkylene main chain can be used as appropriate, and is preferably represented by the following formula.

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

As the organopolysiloxane, those having a siloxane-containing site (siloxane site) as the main chain and an oxyalkylene chain bonded to the end of the main chain are used. By using the organosiloxane having the oxyalkylene chain, it is presumed that the compatibility with the (meth) acrylic polymer and the antistatic component is balanced and light release is realized.

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

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

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

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

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

In addition to the organosiloxane having (bonding) the oxyalkylene chain in the main chain, it is also possible to use an organosiloxane having (bonding) the oxyalkylene chain in the side chain. The use of an organosiloxane having an alkylene chain is a more preferred embodiment. As the organopolysiloxane, an organopolysiloxane having a known polyoxyalkylene side chain can be used as appropriate, and is preferably represented by the following formula.

(Wherein R ₁ is a monovalent organic group, R ₂ , R ₃ and R ₄ are alkylene groups, R ₅ is hydrogen or an organic group, and m and n are integers from 0 to 1000, provided that m and n are simultaneously (A and b are integers from 0 to 100. However, a and b are not 0 at the same time.)

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

Specific examples of the organosiloxane include, for example, commercial names KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF. -642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (Shin-Etsu Chemical) SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ-7001, SH8400, SH8700 SF8410, SF8422 (above, manufactured by Toray Dow Corning), TSF-4 40, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4442, TSF-4460 (manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (manufactured by Big Chemie Japan) 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, more preferably 3 to 14. When the HLB value is out of the above range, the contamination of the adherend is deteriorated, which is not preferable.

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

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

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

Further, specific examples of the acrylic compound having a polyoxyalkylene chain include a (meth) acrylate polymer having an oxyalkylene group. The oxyalkylene group has an addition mole number of oxyalkylene units of preferably 1 to 50, more preferably 2 to 30 from the viewpoint of coordination of the ionic compound when an ionic compound is used as the antistatic component. 2 to 20 is more preferable. The terminal of the oxyalkylene chain may be a hydroxyl group, or may be substituted with an alkyl group, a phenyl group or the like.

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

Further, as the monomer unit (component), other monomer units (components) other than the (meth) acrylic acid alkylene oxide can also 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) ) Acrylates, isodecyl (meth) acrylates, n-dodecyl (meth) acrylates, n-tridecyl (meth) acrylates, n-tetradecyl (meth) acrylates and other acrylates and / or methacrylates having an alkyl group of 1 to 14 carbon atoms And the like.

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

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

The molecular weight of the polyoxyalkylene chain-containing compound not containing the organopolysiloxane is suitably a number average molecular weight (Mn) of 50,000 or less, preferably 200 to 30,000, more preferably 200 to 10,000, 200 to 5000 is preferably used. When Mn is larger than 50000, the compatibility with the acrylic polymer is lowered and the pressure-sensitive adhesive layer tends to be whitened. If Mn is less than 200, contamination with the polyoxyalkylene compound may easily occur. In addition, Mn means the value of polystyrene conversion obtained by GPC (gel permeation chromatography) here.

Specific examples of commercially available polyoxyalkylene chain-containing compounds that do not contain the organopolysiloxane include, for example, Adekapluronic 17R-4, Adekapluronic 25R-2 (all of which are manufactured by ADEKA), Latem PD- 420, Latemul PD-420, Latemul PD-450, Emulgen 120 (manufactured by Kao), Aqualon HS-10, KH-10, Neugen EA-87, EA-137, EA-157, EA-167, EA-177 ( As mentioned above, Daiichi Kogyo Seiyaku Co., Ltd.) can be mentioned.

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 it is easy to achieve both antistatic properties and light releasability (removability).

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

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

When the above isocyanate compound (bifunctional isocyanate compound and trifunctional or higher isocyanate compound) is used in combination, the blending ratio (mass ratio) of both compounds is [bifunctional isocyanate compound] / [3 The functional or higher isocyanate compound] (mass ratio) is preferably 0.1 / 99.9 to 50/50, more preferably 0.1 / 99.9 to 20/80, and 0.1 / 99 9.9 to 10/90 is more preferable, 0.1 / 99.9 to 5/95 is more preferable, and 0.1 / 99.9 to 1/99 is most preferable. By adjusting and blending within the above range, a pressure-sensitive adhesive layer having excellent adhesiveness and repulsion resistance is obtained, which is a preferred embodiment.

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

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

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

The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 20 parts by mass, and preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer. It is more preferably contained, more preferably 0.5 to 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 crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the resulting pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained, It tends to cause glue residue. On the other hand, when the content exceeds 20 parts by mass, the cohesive force of the polymer is large, the fluidity is lowered, and the wettability to the adherend (for example, polarizing plate) becomes insufficient, and the adherend and the pressure-sensitive adhesive. There is a tendency to cause blisters generated between the layer (adhesive composition layer). Furthermore, when the amount of the crosslinking agent is large, the peeling charging property tends to be lowered. These crosslinking agents may be used alone or in combination of two or more.

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

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

Furthermore, the pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer preferably has a weight average molecular weight (Mw) of 1000 or more and less than 30000, more preferably 1500 or more and less than 20000, and still more preferably 2000 or more and less than 10,000. The acrylic oligomer is a (meth) acrylic polymer containing an alicyclic structure-containing (meth) acrylic monomer represented by the following general formula as a monomer unit. It functions as an imparting resin, improves adhesion, and is effective in suppressing the surface protection film from floating.
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]

As the alicyclic hydrocarbon group R ² in the above general formula, an alicyclic carbon such as a cyclohexyl group, an isobornyl group, a dicyclopentanyl group, a dicyclopentenyl group, an adamantyl group, a tricyclopentanyl group, a tricyclopentenyl group, etc. A hydrogen group etc. can be mentioned. Examples of the (meth) acrylic acid ester having such an alicyclic hydrocarbon group include cyclohexyl (meth) acrylate having a cyclohexyl group, isobornyl (meth) acrylate having an isobornyl group, and a dicyclopentanyl group. Mention may be made of esters of (meth) acrylic acid with alicyclic alcohols such as (meth) acrylic acid dicyclopentanyl. Adhesiveness can be improved by giving an acrylic oligomer as a monomer unit an acrylic monomer having a relatively bulky structure.

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

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

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

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

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

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

The total thickness of the surface protective film of the present invention is preferably 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 a preferred embodiment is obtained. In addition, the said total thickness means the sum total of the thickness containing all layers, such as a base material, an adhesive layer, and an antistatic layer.

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

The material constituting the separator includes paper and plastic film, but a plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer Examples thereof include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the separator is usually about 5 to 200 μm, preferably about 10 to 100 μm. It is preferable for it to be in the above-mentioned range since it is excellent in workability for bonding to the pressure-sensitive adhesive layer and workability for peeling from the pressure-sensitive adhesive layer. For the separator, if necessary, mold release and antifouling treatment with a silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, silica powder, etc., coating type, kneading type, vapor deposition type It is also possible to carry out antistatic treatment such as.

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

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

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

<Measurement of weight average molecular weight (Mw)>
The weight average molecular weight (Mw) was measured using a GPC apparatus (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.

Sample concentration: 0.2% by mass (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
column:
Sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1 piece)
Detector: Differential refractometer (RI)
The weight average molecular weight was determined in terms of polystyrene. Moreover, when the measurement of the number average molecular weight (Mn) was required, it measured similarly to 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 Represents the type. ]
Literature values:
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 reference values, “Synthesis / design of acrylic resin and development of new applications” (published by Central Management Development Center Publishing Department) and “Polymer Handbook” (John Wiley & Sons) were referred.

<Measurement of surface resistivity>
The surface resistivity was measured in accordance with JIS-K-6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analytic, Hiresta UP MCP-HT450 type) in an atmosphere of temperature 23 ° C. and humidity 50% RH.
The surface resistivity (Ω / □) measured on the surface of the antistatic layer in the present invention is as follows: immediately after coating (initial), light from a fluorescent lamp at room temperature (23 ° C. × 50% RH) (400 lux) After leaving for 1 month (30 days) in an environment of direct exposure to light (aging), UV irradiation in a 23 ° C. × 50% RH environment (high pressure mercury lamp, integrated light quantity: 4000 mJ / cm ² , irradiation time: 30 seconds) After standing (UV irradiation), under each condition, it is preferably less than 1.0 × 10 ¹¹ , more preferably less than 5.0 × 10 ¹⁰ , and still more preferably 1.0. × ¹⁰ than ^10. A surface protective film exhibiting a surface resistivity within the above range can be suitably used as a surface protective film used in, for example, processing or transporting an article that dislikes static electricity such as a liquid crystal cell or a semiconductor device. The term “immediately after coating” means that the antistatic agent composition (solution) is coated, dried and immediately after the formation of the antistatic layer. The same applies hereinafter.

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

<Measurement of back peel force>
The surface protective film related to each example was cut to a size of 70 mm in width and 100 mm in length, and the product name Cello Tape (registered trademark) (24 mm width, rubber 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 layer) of the surface protective 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 degrees in the same environment, and the back surface peeling force (N / 24 mm: Cellophane or N / 19 mm: vs. No. 31B) was measured.
The back surface peeling force (N / 24 mm: against cello tape) in the present invention is preferably 1 to 15 N / 24 mm, more preferably 2 to 13 N / 24 mm, still more preferably 3 to 10 N / 24 mm. The back surface peeling force (N / 19 mm: 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. It is. If it is out of the above range and the back surface peeling force is too light (too low), the pick-up tape will not adhere to the back surface of the surface protective film, and the surface protective film cannot be peeled off. It becomes difficult to peel off the pickup tape from the film, which is not preferable.

<Measurement of slipperiness (dynamic frictional force)>
The surface protective film is cut to a size of 70 mm in width and 100 mm in length, and is bonded to an acrylic plate (trade name “Acrylite”, manufactured by Mitsubishi Rayon Co., Ltd., thickness: 1 mm, width: 70 mm, length: 100 mm). Prepared. This test piece was placed on a smooth PET film held horizontally with the back surface (antistatic layer surface) facing down, and a load of 1.5 kg was placed on the test piece. The test piece loaded with the load was attached to a tensile tester using a non-stretchable thread, and the test piece was pulled horizontally at a measurement temperature of 25 ° C. under a tensile speed of 300 mm / min and a tensile distance of 300 mm. The average value (n = 3) of the dynamic friction force (N) was determined.
The slipping property (dynamic frictional force) (N) in the present invention is preferably 2 to 5, more preferably 2 to 4.8 or less, and further preferably 3 to 4.5 or less. is there. Within the above range, when handling an adherend to which a surface protective film is attached, the back surface of the surface protective film (antistatic layer surface) has good sliding properties and is compatible with the back surface peeling force (adhesive strength). This is advantageous in terms of workability.

<Solvent resistance (appearance)>
When the antistatic layer of the antistatic layer (back layer) of the surface protection film in each example is wiped 10 times with Bencot (Asahi Kasei Fibers Co., Ltd.) soaked in ethanol, and the antistatic layer is detached. X, and the case where the antistatic layer was not detached was evaluated as ◯.

<Solvent resistance (measurement of surface resistivity)>
The antistatic layer (back layer) of the surface protective film in each example was wiped 10 times with a bencott soaked in ethanol (manufactured by Asahi Kasei Fibers), and the resistivity meter (Mitsubishi) under an atmosphere of temperature 23 ° C. and humidity 50% RH. The surface resistivity was measured according to JIS-K-6911 using Hiresta UP MCP-HT450 type manufactured by Chemical Analytics.
The surface resistivity (Ω / □) measured on the surface of the antistatic layer in the present invention is preferably less than 1.0 × 10 ¹¹ , more preferably less than 5.0 × 10 ¹⁰ . More preferably, it is less than 1.0 × 10 ¹⁰ . The surface protective film showing the surface resistivity within the above range is, for example, to wipe off dirt on the surface protective film, so that even when wiped with ethanol, the surface resistivity can be kept low, such as a liquid crystal cell or a semiconductor device. Thus, it can be suitably used as a surface protective film used in processing or conveying processes of articles that dislike static electricity.

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

<Measurement of film side peeling voltage (antistatic layer side of surface protective film)>
In the same manner as the measurement of the polarizing plate peeling voltage, the surface protective film 1 was peeled from the surface of the polarizing plate 20 so that the peeling angle was 150 ° and the peeling speed was 10 m / min. The potential of the surface protective film 1 generated at this time is measured by a potential measuring device 40 (model “KSD-0103” manufactured by Kasuga Denki Co., Ltd.), which is fixed at a position 100 mm from the center of the surface protective film 1. “Initial film side peeling voltage” was measured. The measurement was performed in an environment of 23 ° C. and 50% RH.
In addition, after being allowed to stand for 1 month (30 days) in an environment where light from a fluorescent lamp (400 lux) is directly applied at room temperature (23 ° C. × 50% RH), Measured as “time-lapse film side peeling voltage”, and after UV irradiation (high pressure mercury lamp, integrated light amount: 4000 mJ / cm ² , irradiation time: 30 seconds) in an environment of 23 ° C. × 50% RH, The film side peeling band voltage after UV irradiation ”was measured, and these measurements were performed in an environment of 23 ° C. × 50% RH.
In addition, a film side peeling voltage is a peeling voltage derived from the antistatic layer which comprises the surface protection film of this invention, and contributes to antistatic property.
The film side peeling voltage (kV) in the present invention (absolute value, initial, time, all after UV irradiation) is preferably 0.6 or less, more preferably 0.5 or less, and still more preferably. Is 0.4 or less. Within the above range, the surface protective film after peeling is not charged and is excellent in workability.

<Preparation of aqueous dispersion for antistatic layer A>
As a binder, polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.), as a conductive polymer, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.), and poly (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, fatty acid as lubricant Oleic acid amide, which is an amide, in a mixed solvent of water / ethanol (1/1), binder is 100 parts by mass in solid content, polyaniline sulfonic acid is 80 parts by mass in solid content, and PEDOT / PSS is 20 parts by mass in solid content , The cross-linking agent in a solid content of 10 Part by mass and 10 parts by mass of lubricant were added, and the mixture was stirred for about 20 minutes and mixed well. In this way, an aqueous dispersion for antistatic layer A having an NV of about 0.4% was prepared.

<Preparation of aqueous dispersion for antistatic layer B>
As a binder, polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.), as a conductive polymer, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.), and poly (3, 4-ethylenedioxythiophene) (PEDOT) / polystyrene sulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), methoxylated methylol melamine as a cross-linking agent, and carbinol-modified poly (silicone) as a lubricant. Dimethylsiloxane (BY16-201, manufactured by Toray Dow Corning) in a water / ethanol (1/1) mixed solvent, binder in a solid content of 100 parts by mass, polyaniline sulfonic acid in a solid content of 45 parts by mass, PEDOT / 30 parts by mass of PSS in solid content, crosslinking agent Was added in an amount of 10 parts by mass and the lubricant was added in an amount of 10 parts by mass. The mixture was stirred for about 20 minutes and mixed well. Thus, an aqueous dispersion for antistatic layer B having an NV of about 0.4% was prepared.

<Preparation of aqueous dispersion for antistatic layer C>
As a binder, polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.), as a conductive polymer, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.), and poly (3, 4-ethylenedioxythiophene) (PEDOT) / polystyrene sulfonic acid (PSS) (Baytron P, H, C, manufactured by Starck), isocyanurate of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent, and methoxylation Methylolmelamine, a fluorine-containing block copolymer (Modiper F200, manufactured by NOF Corporation) as a lubricant, a water / ethanol (1/1) mixed solvent, a binder in a solid content of 100 parts by mass, and polyanilinesulfonic acid as a lubricant The solid content 25 parts by mass, 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 lubricant in solids, and stirred for about 20 minutes and mixed well . Thus, an aqueous dispersion for antistatic layer C having an NV of about 0.4% was prepared.

<Preparation of aqueous dispersion for antistatic layer D>
As a binder, polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.), as a conductive polymer, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.), and poly (3, 4-ethylenedioxythiophene) (PEDOT) / polystyrene sulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), methoxylated methylol melamine as a crosslinking agent, and carnauba wax as a wax-based lubricant as water. In a mixed solvent of / ethanol (1/1), the binder is 100 parts by mass in solid amount, the polyanilinesulfonic acid is 20 parts by mass, PEDOT / PSS is 80 parts by mass, and the cross-linking agent is 10 in solids. Add 20 parts by weight of solids and lubricant and add 20 parts by weight for about 20 minutes Stir and mix well. In this way, an aqueous dispersion for antistatic layer D having an NV of about 0.4% was prepared.

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

<Preparation of aqueous dispersion for antistatic layers EJ>
In addition, based on the content of Table 1, the aqueous dispersions for antistatic layers E to J were obtained in the same manner as the preparation of the aqueous dispersion for antistatic layers A to D.

<Preparation of aqueous dispersion for antistatic layer L>
As a binder, polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.), as a conductive polymer, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.), and poly (3, 4-ethylenedioxythiophene) (PEDOT) / polystyrenesulfonic acid (PSS) (Baytron P, H, C, manufactured by Starck), isocyanurate of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent, fluorine as a lubricant Fluorine-containing block copolymer (Modiper F200, manufactured by NOF Corporation), a system lubricant, in a mixed solvent of water / ethanol (1/1), binder in a solid content of 100 parts by mass, and polyaniline sulfonic acid in a solid content of 25 parts by mass , Fix PEDOT / PSS 25 parts by mass in form, 10 parts by mass in solid content of the cross-linking agent, and 170 parts by mass in solid quantity of lubricant were added and stirred for about 20 minutes and mixed well. In this way, an aqueous dispersion for 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), and poly (3,4-ethylenedioxy) as a conductive polymer Thiophene) (PEDOT) / polystyrene sulfonic acid (PSS) (manufactured by Baytron P, H, C, Starck), methoxylated methylol melamine as a crosslinking agent, carnauba wax as a wax-based lubricant as water / ethanol (1 / In the mixed solvent of 1), 100 parts by mass of the binder in solid amount, 10 parts by mass of polyaniline, 90 parts by mass of PEDOT / PSS, 10 parts by mass of the crosslinking agent, and 10 parts by mass of the lubricant And 20 parts by mass was added and stirred for about 20 minutes to mix thoroughly. In this way, an aqueous dispersion for 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 inlet tube, and a condenser, 100 parts by mass of 2-ethylhexyl acrylate (2EHA), 4 parts by mass of 2-hydroxyethyl acrylate (HEA), 2 as a polymerization initiator 2,2'-azobisisobutyronitrile and 157 parts by mass of ethyl acetate were charged, nitrogen gas was introduced with gentle stirring, and the temperature in the flask was kept at around 65 ° C for 6 hours of polymerization. Reaction was performed 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 inlet tube, and a condenser, 100 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of 4-hydroxybutyl acrylate (4HBA), acrylic acid (AA) 0.02 part by mass, 0.1 part by mass of N-vinylpyrrolidone (NVP), 0.2 part by mass of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 157 parts by mass of ethyl acetate were charged gently. Nitrogen gas was introduced while stirring, and the polymerization temperature was kept at about 65 ° C. for 6 hours to prepare an acrylic polymer 8 solution (40% by 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 to 7, 9 and 10 for the pressure-sensitive adhesive layer>
Acrylic polymers 2 to 7, 9 and 10 were obtained in the same manner as the method for preparing the acrylic polymer 1 or 8 for the pressure-sensitive adhesive layer. In addition, about components other than a monomer component, the same quantity as the acrylic polymer 1 was mix | blended.

<Preparation of Acrylic Adhesive 1 Solution for Adhesive Layer>
The acrylic polymer 1 solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and isocyanurate of hexamethylene diisocyanate (Nippon Polyurethane) is added to 500 parts by mass (100 parts by mass of solid content) of this solution as a crosslinking agent. Kogyo Co., Ltd., Coronate HX: C / HX) 3.5 parts by mass (solid content 3.5 parts by mass), 3 parts by mass (solid content 0.03 mass) of dibutyltin dilaurate (1% by mass ethyl acetate solution) as a crosslinking catalyst Part) was added 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) is diluted to 20% by mass with ethyl acetate, and an organopolysiloxane (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.) is added to 500 parts by mass of this solution (solid content 100 parts by mass). 2 parts by weight of a solution diluted with ethyl acetate to 10% (solid content: 0.2 parts by weight), as an alkali metal salt as an antistatic component, lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO ₂ ) ₂ : LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted to 1% with ethyl acetate 15 parts by mass (solid content 0.15 parts by mass), as a crosslinking agent, isocyanurate of hexamethylene diisocyanate (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 (three Chemical Co., Takenate 600) 0.3 parts by mass (solid content 0.3 parts by mass), as a crosslinking catalyst, iron (III) acetylacetonate (1% by mass ethyl acetate solution) 0.5 parts by mass (solid content 0) 0.005 parts by mass) was added and mixed and agitated to prepare an acrylic pressure-sensitive adhesive 10 solution.

<Preparation of Acrylic Adhesive 2-9 Solution for Adhesive Layer>
In the same manner as the method for preparing the acrylic pressure-sensitive adhesive 1 or 10, acrylic pressure-sensitive adhesive 2 to 9 solutions were obtained.

<Preparation of urethane adhesive 11 solution>
As a polyol, 85 parts by mass of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) which is a polyol having three hydroxyl groups, Sanniks GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn = 3000) 13 which is a polyol having three hydroxyl groups 2 parts by mass of Sannix GP1000 (Sanyo Kasei Co., Ltd., Mn = 1000) which is a polyol having three hydroxyl groups, 18 parts by mass of an isocyanate compound as a crosslinking agent (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.) As a catalyst, 0.04 parts by mass of iron (III) acetylacetonate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 210 parts by mass of ethyl acetate as a diluting solvent were blended to obtain a urethane-based adhesive 11 solution. In addition, as a raw material of a urethane type adhesive solution, all except a solvent are raw materials with a density | concentration of 100%.

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

<Preparation of urethane adhesive 13 solution>
The urethane-based pressure-sensitive adhesive 11 solution described above except that 30 parts by mass of isopropyl myristate (Exepal IPM, manufactured by Kao Corporation) is added as a wettability improver and 0.5 part by mass of Irganox 1010 (manufactured by BASF) is added as an antioxidant. In the same manner as above, a urethane pressure-sensitive adhesive 13 solution was obtained.

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

<Preparation of silicone pressure sensitive adhesive 15 solution>
As a silicone adhesive, “X-40-3229” (solid content 60 mass%, manufactured by Shin-Etsu Chemical Co., Ltd.) is 100 mass parts in solid content, and as a platinum catalyst, “CAT-PL-50T” (Shin-Etsu Chemical Co., Ltd.). (Manufactured) 0.5 parts by mass and 100 parts by mass of toluene as a solvent were blended to obtain a silicone adhesive 15 solution.

<Preparation of silicone adhesive 16 solution>
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 as} an antistatic component: LiTFSI, Tokyo Chemical Industry Co., Ltd. (Manufactured) A silicone pressure sensitive adhesive 16 solution was obtained in the same manner as the silicone pressure sensitive adhesive 15 solution except that 0.3 part by mass was further added.

<Preparation of base material with antistatic layer>
To 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, the aqueous dispersion of any one of the antistatic layers (A) to (K) is dried. It apply | coated so that it might become 20, 30, 45 nm. The coated material was heated to 130 ° C. for 1 minute and dried to prepare a substrate with an antistatic layer having an antistatic layer on the first surface of the PET film.

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

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

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

<Examples 2 to 10, Example 17, Example 18, and Comparative Examples 1 to 5>
Based on the contents of Tables 1 to 3, surface protective films were produced in the same manner as in Example 1.

<Examples 12 to 14>
Based on the contents of Tables 1 and 4, surface protective films were produced in the same manner as Example 11.

<Example 16>
Based on the contents of Tables 1 and 5, surface protective films were produced in the same manner as Example 15.

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

Abbreviations in Table 2 and Table 3 will be described below. Abbreviations in other tables are based on 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 compounds]
KF353: Organopolysiloxane having an oxyalkylene chain (HLB value: 10) (trade name: KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.)
KF6004: Organopolysiloxane having an oxyalkylene chain (HLB value: 9) (trade name: KF-6004, manufactured by Shin-Etsu Chemical Co., Ltd.)
HS10: manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name “AQUALON HS-10” (anionic surfactant)
EA137: Daiichi 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.) (active ingredient 100%)
BMPTFSI: 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide (ionic liquid, Sigma Aldrich, liquid at 25 ° C.) (active ingredient 100%)
EMIFSI: ionic liquid: 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (ionic liquid, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (active ingredient 100%)

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

[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.)

Note) “> 1E + 13” in the table means exceeding 10 13.

From Table 6, it is excellent in surface resistivity, a film side peeling voltage, etc. in all Examples, and when an ionic compound which is an antistatic agent and a polyether compound are blended, a polarizing plate peeling voltage In addition, when a lubricant is blended in the antistatic layer, the slipperiness is also excellent, and when an antistatic component is blended in the pressure-sensitive adhesive layer, it can be confirmed that the polarizing plate stripping voltage is also excellent. It was. Moreover, compared with Example 17 using an acrylic resin as a binder, in the Example using a polyester resin, it has confirmed that it was excellent also in solvent resistance.

On the other hand, from Table 6, in Comparative Examples 1 to 5, since the conductive polymer constituting the antistatic layer was not blended at a desired ratio, the surface resistivity and the film-side peeling band voltage after time and after UV irradiation were carried out. It was confirmed to be inferior to the examples. In particular, in Comparative Example 5, since the externally doped polyaniline was used instead of the self-doped polyaniline sulfonic acid having its own conductivity, the polythiophenes (PEDOT) to the polyanions (PSS) (corresponding to the dopant over time) It was confirmed that the surface resistivity over time was inferior to that of the example.

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

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

Claims

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 an antistatic agent composition containing polyanilinesulfonic acid and polythiophenes doped with polyanions as a conductive polymer component, and a binder,
A surface protective film, wherein a blending ratio (mass ratio) of the polyaniline sulfonic acid and the polythiophenes doped with the polyanions is 90:10 to 10:90.
The surface protective film according to claim 1, wherein the polythiophene is poly (3,4-ethylenedioxythiophene) (PEDOT).
The surface protection film according to claim 1 or 2, wherein the polyanions are polystyrene sulfonic acid (PSS).
The surface protective film according to any one of claims 1 to 3, wherein the binder is a polyester resin.
The surface protective film according to any one of claims 1 to 4, wherein the antistatic agent composition contains a melamine-based crosslinking agent and / or an isocyanate-based crosslinking agent as a crosslinking agent.
The antistatic agent composition contains at least one selected from the group consisting of a fatty acid amide, a fatty acid ester, a silicone lubricant, a fluorine lubricant, and a wax lubricant as a lubricant. The surface protective film according to any one of 5 to 5.
The surface protective film according to any one of claims 1 to 6, wherein the substrate is a polyester film.
The pressure-sensitive adhesive composition contains at least one selected from the group consisting of an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive. The surface protective film as described.
The surface protective film according to any one of claims 1 to 8, wherein the pressure-sensitive adhesive composition contains a polyether compound.
10. The surface protection film according to claim 1, wherein the pressure-sensitive adhesive composition contains an antistatic component.
An optical member which is protected by the surface protective film according to any one of claims 1 to 10.