WO2017115644A1

WO2017115644A1 - Surface protection film, method for producing surface protection film, and optical member

Info

Publication number: WO2017115644A1
Application number: PCT/JP2016/087069
Authority: WO
Inventors: 賢一片岡; 天野　立巳
Original assignee: 日東電工株式会社
Priority date: 2015-12-28
Filing date: 2016-12-13
Publication date: 2017-07-06
Also published as: TW201736130A; CN108368394A; JP2017119753A; KR20180097576A

Abstract

Provided are: a surface protection film which is capable of achieving antistatic properties, long-term stability of the peeling-charged electrostatic potential and print adhesion; a method for producing this surface protection film; and an optical member. A surface protection film according to the present invention is provided with: a base having a first surface and a second surface; an antistatic layer that is provided on the first surface of the base; and an adhesive layer that is formed on the second surface of the base with use of an adhesive composition. This surface protection film is characterized in that the antistatic layer is formed with use of an antistatic agent composition that contains a polyaniline sulfonic acid that serves as a conductive polymer component, a polyester resin that serves as a binder, and a melamine-based crosslinking agent that serves as a crosslinking agent.

Description

Surface protective film, method for manufacturing surface protective film, and optical member

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

The present invention includes a base material having a first surface and a second surface, an antistatic layer provided on the first surface of the base material, and an adhesive layer provided on the second surface of the base material. In detail, it is related with the surface protection film provided with the antistatic function. The surface protective film according to the present invention is suitable for applications that are affixed to plastic products and the like that are likely to generate static electricity. In particular, optical members (for example, polarizing plates used for liquid crystal displays, wavelength plates, retardation plates, optical compensation films, reflective sheets, brightness enhancement films, hard coat films used for touch panels, antireflection films, antiblocks, etc. It is useful as a surface protective film used for the purpose of protecting the surface of a layered film or the like.

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 Documents 1 and 2).

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

In addition, when the surface resistivity or the like increases (deteriorates), static electricity is generated when the surface protective film is peeled off from the adherend, which may cause a problem.

JP 2004-223923 A JP 2008-255332 A

Therefore, in view of the above circumstances, the present invention has been intensively studied, and as a result, surface protection film that can achieve antistatic property, stability of peeling band voltage, and print adhesion, method for manufacturing surface protection film, and optical An object is to provide a member.

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. And a pressure-sensitive adhesive layer formed using the adhesive composition, wherein the antistatic layer comprises a polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and a melamine-based as a cross-linking agent It is formed using the antistatic agent composition containing 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 an antistatic component.

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

The method for producing a surface protective film of the present invention is a method for producing the surface protective film, comprising polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and a melamine-based cross-linking agent as a cross-linking agent. And a step of preparing an antistatic layer by applying and drying the antistatic agent composition on the first surface of the substrate.

In the surface protective film of the present invention, the antistatic layer provided on the first surface (back surface) of the base material is formed of an antistatic agent composition containing a specific conductive polymer component, a binder, and a crosslinking agent. Therefore, it is possible to form a uniform antistatic layer, excellent workability, excellent antistatic properties due to the antistatic layer, stability over time of the stripping voltage, and print adhesion It is possible to provide a surface protective film capable of achieving the above, a method for producing the surface protective film, and an optical member protected by the surface protective film.

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 a form called an adhesive sheet, an adhesive tape, an adhesive label, an adhesive film or the like, and in particular, an optical member (for example, a liquid crystal display panel such as a polarizing plate or a wave plate) It is suitable as a surface protective film that protects the surface of an optical member during processing or transport of an optical member used as a component or an optical member used for a touch panel display such as a hard coat film). 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 of the base material 12, and a second surface of the base material 12 (an antistatic layer 11). And an adhesive layer 13 provided on the opposite 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 member 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 improving the adhesion between the substrate 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 100 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 comprises a substrate having a first surface (back surface) and a second surface (surface opposite to the first surface), and an antistatic layer provided on the first surface of the substrate. The antistatic layer is formed using a polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an antistatic agent composition containing a melamine-based crosslinking agent as a crosslinking agent. It is characterized by being made. When the surface protective film has an antistatic layer (topcoat layer), the antistatic property due to the antistatic layer, the stability over time of the stripping voltage, and the print adhesion are improved, which is a preferred embodiment.

<Conductive polymer>
The antistatic agent composition contains polyaniline sulfonic acid as a conductive polymer component. By using the conductive polymer, the antistatic property due to the antistatic layer and the stability over time of the stripping voltage can be satisfied. The polyaniline sulfonic acid is “water-soluble”, but can be immobilized in the antistatic layer by using a melamine-based cross-linking agent described later to improve water resistance. By using an aqueous solution containing a conductive polymer, an antistatic layer having excellent surface resistivity over time is obtained, which is a preferred embodiment. On the other hand, unlike the present invention, when the conductive polymer used in forming the antistatic layer is “water-dispersible”, the antistatic layer is prepared using a dispersion containing the water-dispersible conductive polymer. When the film is formed, agglomerates are easily generated, it is difficult to form a uniform layer of the conductive polymer, and the obtained antistatic layer tends to deteriorate the surface resistivity over time, which is not preferable.

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

The polyaniline sulfonic acid used as the conductive polymer component preferably has a standard polystyrene equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 5 × 10 ⁵ or less. × 10 ⁵ or less is more preferable. 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.

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

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

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

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

<Binder>
The antistatic layer is characterized by containing a polyester resin as a binder as an essential component in order to impart solvent resistance, mechanical strength, and thermal stability. 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 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 two 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.

Examples of compounds that can be employed as the polyhydric alcohol component include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neo Pentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl-1, Examples include diols such as 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A, and bisphenol A. It is done. Other examples include alkylene oxide adducts (for example, ethylene oxide adducts, propylene oxide adducts, etc.) of these compounds.

The molecular weight of the polyester resin is, for example, about 5 × 10 ³ to 1.5 × 10 ⁵ (preferably 1 × 10 5) as the number average molecular weight (Mn) in terms of standard polystyrene measured by gel permeation chromatography (GPC). ⁴ to about 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, for example, trade names Vylonal MD-1100, MD-1200, MD-1245, MD-1335, MD-1480, MD-1500, MD-2000 manufactured by Toyobo Co., Ltd. Name Plus Coat Z-221, Z-446, Z-561, Z-565, Z-880, RZ-105, RZ-570, Z-592, Z-687, Z-690, Pes Resin A manufactured by Takamatsu Yushi Co., Ltd. -110F, A-120, A-124GP, A-125S, A-520, A-613D, A-615GE, A-640, A-645GH, A-647GEX, A-684G and the like.

The antistatic layer is a resin other than a polyester resin (for example, acrylic resin, acrylic-urethane) 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-styrene resin, acrylic-silicone resin, silicone resin, polysilazane resin, polyurethane resin, fluororesin, polyolefin resin, and the like. A preferred embodiment of the technology disclosed herein is a case where the binder of the antistatic layer is substantially composed only of a polyester resin. For example, 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 agent composition used when forming the antistatic layer in the technique disclosed herein is a lubricant comprising a fatty acid amide, a fatty acid ester, a silicone lubricant, a fluorine lubricant, and a wax lubricant. It is a preferred embodiment to use at least one selected. By using these lubricants as a lubricant, a further release treatment (for example, a treatment in which a known release treatment agent such as a silicone release agent or a long-chain alkyl release agent is applied and dried) is applied to the surface of the antistatic layer. Even in the case where the coating is not performed, an antistatic layer having both sufficient slipping property and printing adhesion can be obtained, so that it can be a preferable mode. Thus, the aspect in which the surface of the antistatic layer is not further peeled can prevent whitening due to the peeling treatment agent (for example, whitening due to storage under heating and humidification conditions). This is preferable. It is also advantageous from the viewpoint of solvent resistance.

Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, 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 and perfluorocarboxylic acid ester. 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. If the content of the lubricant is too large, the print adhesion may be lowered.

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

As the melamine-based crosslinking agent, melamine, alkylated melamine, methylol melamine, alkoxylated methyl melamine, alkyl etherified melamine and the like can be used. In addition, another crosslinking agent can be mix | blended in the limit which does not impair significantly the performance (for example, performance, such as antistatic property) of the surface protection film disclosed here.

The antistatic layer in the technology disclosed herein is, if necessary, other antistatic agents, antioxidants, colorants (pigments, dyes, etc.), fluidity adjusting agents (thixotropic agents, thickeners, etc.), 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 method for producing a surface protective film of the present invention comprises a step of preparing an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and a melamine-based cross-linking agent as a cross-linking agent; Applying an antistatic composition to the first surface of the substrate and drying to prepare an antistatic layer. In particular, as a method for forming the antistatic layer, an antistatic agent composition (liquid composition) in which essential components such as the conductive polymer component and additives used as necessary are dissolved in an appropriate solvent (water or the like). And a coating material for forming an antistatic layer) and applying it to a substrate can be suitably formed. For example, a method of applying the antistatic agent composition 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 antistatic composition can be, for example, 5% by mass or less (typically 0.05 to 5% by mass), and is usually 1% by mass or less (typically 0%). 10 to 1% by mass). In the case of forming an antistatic layer having a small thickness, it is preferable that the NV of the antistatic agent composition is 0.05 to 0.50% by mass (for example, 0.10 to 0.40% by mass). Thus, by using a low NV antistatic agent composition, a more uniform antistatic layer can be formed.

The solvent constituting the antistatic agent composition is preferably a solvent that can stably dissolve 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 antistatic agent composition is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol).

<Properties of antistatic layer>
The thickness of the antistatic layer in the technique disclosed herein is typically 3 to 500 nm, preferably 3 to 100 nm, 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 1.0 × 10 ¹¹ or less, more preferably , and a 5.0 × ^{10 10} or less, further preferably 1.0 × ^{10 10} or less. 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. In addition, the said surface resistivity can be calculated | required from the surface resistivity measured in 23 degreeC and 50% RH atmosphere using a commercially available insulation resistance measuring apparatus.

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 is used to provide an identification number or the like of the adherend to be protected in the process of carrying or transporting the adherend (for example, an optical member) performed with the surface protective film 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 a pressure-sensitive adhesive layer formed on the second surface of the base material using a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition has adhesiveness. Can be used without any particular restrictions. For example, as the pressure-sensitive adhesive composition, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a synthetic rubber-based pressure-sensitive adhesive, a natural rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and the like can be used. It is at least one selected from the group consisting of a PSA adhesive, a urethane PSA, and a silicone PSA, and particularly preferably by using an acrylic PSA using a (meth) acrylic polymer. is there.

<Acrylic adhesive>
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 as a main component. By using the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend (protected body) to be low, and the light peelability and re-peeling are facilitated. A surface protective film having excellent properties can be obtained. In the present invention, the (meth) acrylic polymer refers to an acrylic polymer and / or a methacrylic polymer, and the (meth) acrylate refers to acrylate and / or methacrylate. Further, the “main component” in the present invention means the largest component in the total amount of constituent components, preferably more than 40% by mass, more preferably more than 50% by mass, and still more preferably 60% by mass. It means exceeding%.

Examples of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate , Isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, and the like.

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. A (meth) acrylic monomer having an alkyl group is preferred. In particular, by using a (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend to be low, and the removability is excellent.

In particular, it is preferable to contain 50% by mass or more of a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms with respect to 100% by mass of the total amount of monomer components constituting the (meth) acrylic polymer. More preferably, it is 60% by mass or more, more preferably 70 to 99% by mass, and most preferably 80 to 97% 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.

The (meth) acrylic polymer constituting the acrylic pressure-sensitive adhesive preferably contains a (meth) acrylic monomer having a hydroxyl group as a raw material monomer. As the (meth) acrylic monomer having a hydroxyl group, one or more kinds can be used.

By using the (meth) acrylic monomer having a hydroxyl group, it is easy to control the crosslinking of the pressure-sensitive adhesive composition, and it is easy to control the balance between the improvement of wettability by flow and the reduction of the adhesive strength in peeling. Become. Furthermore, unlike carboxyl groups and sulfonate groups that can generally act as cross-linking sites, hydroxyl groups have an appropriate interaction with ionic compounds, which are antistatic components (antistatic agents), and so on. Also in terms of surface, it can be suitably used.

Examples of the (meth) acrylic monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth). Acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate, N-methylol (meth) acrylamide, etc. Is given. In particular, it is preferable to use a (meth) acrylic monomer having a hydroxyl group having 4 or more carbon atoms in the alkyl group, since light release at the time of high-speed peeling is easy.

It is preferable to contain 15 parts by mass or less of the (meth) acrylic monomer having a hydroxyl group with respect to 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. Is 1 to 13 parts by weight, more preferably 2 to 10 parts by weight, and most preferably 3 to 8 parts by weight. 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.

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

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

The (meth) acrylic monomer having a carboxyl group 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 less than 1 part by weight, more preferably less than 1 part by weight, even more preferably less than 0.2 part by weight, and most preferably less than 0.01 part by weight and less than 0.1 part by weight. When the amount exceeds 5 parts by mass, a large number of acid functional groups such as carboxyl groups having a large polar action exist, and when an ionic compound is blended as an antistatic component, an acid functional group such as a carboxyl group is included in the ionic compound. By interacting with each other, ion conduction is hindered, conductivity efficiency is lowered, and sufficient antistatic properties may not be obtained, which is not preferable. Within the above range, it is possible to prevent the adhesive force from increasing with time (adhesive force increase preventing property), which is preferable.

It is also possible to use a (meth) acrylic monomer having a hydroxyl group and a (meth) acrylic monomer having a carboxyl group in combination, particularly for the purpose of achieving both peeling charging properties and an adhesive strength preventing property. is there.

Furthermore, the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the (meth) acrylic monomer having a hydroxyl group, and the (meth) having a carboxyl group, which are used in the (meth) acrylic polymer. Other polymerizable monomers other than acrylic monomers can be used without particular limitation as long as they do not impair the characteristics of the present invention. For example, cohesive strength / heat resistance improving components such as cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine In addition, a component having a functional group functioning as an adhesive strength improvement or a crosslinking base point such as a vinyl ether monomer can be appropriately used. Among them, it is preferable to use a nitrogen-containing monomer such as a cyano group-containing monomer, an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, and N-acryloylmorpholine. Use of a nitrogen-containing monomer is useful because it can secure an appropriate adhesive force that does not cause floating or peeling, and can provide a surface protective film having excellent shearing force. These polymerizable monomers may be used alone or in combination of two or more.

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

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

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

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

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

In the present invention, other polymerizable monomers other than the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the (meth) acrylic monomer having a hydroxyl group, and the (meth) acrylic monomer having a carboxyl group are: 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 an ionic compound is used as an antistatic agent, a good interaction with the ionic compound and a good removability can be appropriately adjusted. .

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

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

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

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

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

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

Specific examples of the (meth) acrylic acid alkylene oxide adduct include, for example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, polyethylene glycol-polybutylene glycol (meth) ) Acrylate, polypropylene glycol-polybutylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, octoxy polyethylene glycol (meth) acrylate, lauroxy polyethylene Glycol (meth) acrylate, stearoxy polyethylene glycol 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. Is 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 2,000,000, and further preferably 300,000 to 800,000. 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.

<Urethane adhesive>
When using a urethane-type adhesive for the said adhesive layer, arbitrary appropriate urethane-type adhesives can be employ | adopted. 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.

<Silicon adhesive>
When using a silicone type adhesive for the said adhesive layer, arbitrary appropriate silicone type adhesives can be employ | 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 H ₄ (CH ₃ ) SO ₃ ⁻ , (C ₂ F ₅ ) ₃ PF ₃ ⁻ , CH ₃ CH (OH) COO ⁻ , and a metal salt composed of (FSO ₂ ) ₂ N ⁻ Used. More _{_{_{_{preferably, LiBr, LiI, LiBF 4,}}}} LiPF 6, LiSCN, LiClO 4, LiCF 3 SO 3, Li (CF 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, Li (FSO 2 _{_{) 2 N, Li (CF 3}} SO 2) lithium salts such as 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-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1-methyl-1-ethylpyrrole Dinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, pyrrolidinium-2-one cation, 1-propylpiperidinium cation, 1-methyl-1 -Ethylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole Cation, N-ethyl-N-methylmol Such as O Li cation.

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-ethyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1- (2-methoxyethyl) -3-methylimidazolium cation, 1,3-dimethyl-1,4,5, 6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydro Pyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-di Til-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation Etc.

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, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium 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, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, Tetramethylphosphonium ON, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, diallyldimethylammonium cation, tributyl- (2-methoxyethyl) phosphonium And cations. Among them, asymmetric such as triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation 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-heptylua Monium cation, N, N-dimethyl-N-ethyl-N-nonylammonium 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, 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, trioctylmethylammonium cation, N-methyl-N-ethyl- N-propyl-N-pliers Ammonium 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 bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethanesulfonyl) imide, 1-hexylpyridinium tetrafluoroborate 1-methyl-1-ethylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1- Silpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1- Hexylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (pentafluoroethanesulfonyl) imide 1-methyl-1-hexylpiperidinium bis (pentafluoroethanesulfonyl) imide, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethyl Indole 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-methylimidazolium perfluorobutanesulfonate, 1-ethyl-3-methylimidazolium di Cyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl 3-Methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetra Fluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 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 ( Trifluorometa Sulfonyl) imide, tetrapentylammonium trifluoromethanesulfonate, tetrapentylammonium bis (trifluoromethanesulfonyl) imide, tetrahexylammonium trifluoromethanesulfonate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, tetrahebutylammonium trifluoromethanesulfonate, tetraheptyl Ammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (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, glycidyltrimethyl Ammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, tetraoctylphosphonium trifluoro Lomethanesulfonate, tetraoctylphosphonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butylammonium 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-propyl-N-butylammonium bis (trifluoromethanesulfonyl) Imido, N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl Ru-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl- N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl- N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyri Ni (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N-ethyl-N-methylmorpholinium thiocyanate, 4-ethyl-4-methylmorpholinium Examples thereof include methyl carbonate.

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

For example, the antistatic component (ionic compound) is contained with respect to 100 parts by mass of a polymer (for example, (meth) acrylic polymer, urethane polymer, silicone polymer, etc.) that is a main component of the pressure-sensitive adhesive composition. The amount is preferably less than 10 parts by mass, more preferably 5 parts by mass or less, further preferably 0.001 to 3 parts by mass, particularly preferably 0.005 to 0.9 parts by mass, and 0.01 to 0.5 parts by mass. Part is most preferred. It is preferable for it to be in the above-mentioned range since it is easy to achieve both antistatic properties and low contamination.

<Organopolysiloxane having an oxyalkylene chain>
In the surface protective film of the present invention, the pressure-sensitive adhesive composition more preferably contains an organopolysiloxane having an oxyalkylene chain, and more preferably contains an organopolysiloxane having an oxyalkylene side chain. By using the organopolysiloxane, the surface free energy on the pressure-sensitive adhesive surface is reduced, and it is presumed that light release has been 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, for example, it is presumed that the compatibility of the (meth) acrylic polymer and the ionic compound is balanced and light release is realized.

Moreover, as said organopolysiloxane in this invention, the following structures can be used, for example. Specifically, R ₁ and / or R ₂ in the formula has an oxyalkylene chain containing a hydrocarbon group having 1 to 6 carbon atoms, and 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. Use of an organosiloxane having an alkylene chain is a preferred embodiment because it is easy to achieve both antistatic properties and low contamination. 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 is preferably an ethylene group or a propylene group in order to increase the concentration of an ionic compound that can be dissolved in the polyoxyalkylene side chain. R ₅ may be an alkyl group such as a methyl group, an ethyl group or a propyl group, or a monovalent organic group exemplified by an acyl group such as an acetyl group or a propionyl group, each having a substituent such as a hydroxyl group. It may be. These compounds may be used alone or in combination of two or more. Moreover, you may have reactive substituents, such as a (meth) acryloyl group, an allyl group, and a hydroxyl group, in a molecule | numerator. Among the organosiloxanes having a polyoxyalkylene side chain, an organosiloxane having a polyoxyalkylene side chain having a hydroxyl group terminal is presumed to have a good balance of compatibility.

Specific examples of the organosiloxane include, for example, commercial names KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF. -642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (Shin-Etsu Chemical) SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ-7001, SH8400, SH8700 SF8410, SF8422 (above, manufactured by Toray Dow Corning), TSF-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.

For example, with respect to 100 parts by mass of a polymer (for example, (meth) acrylic polymer, urethane polymer, silicone polymer, etc.) that is a main component of the pressure-sensitive adhesive composition, the content of the organopolysiloxane is 0. The amount is preferably 01 to 5 parts by mass, more preferably 0.03 to 3 parts by mass, still more preferably 0.05 to 1 part by mass, and most preferably 0.05 to 0.5 parts by mass. It is preferable for it to be in the above-mentioned range since both antistatic properties and light releasability (removability) can be easily achieved.

The pressure-sensitive adhesive composition may contain a polyoxyalkylene chain-containing compound that is a polyether component that does not contain organopolysiloxane. In particular, after the surface protective film is peeled from the optical member, when another member is bonded to the optical member with an adhesive or an adhesive, the wettability of the adhesive or the adhesive can be improved. Can do.

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 stealth salts; other cationic surfactants having polyoxyalkylene chains (polyalkylene oxide chains), amphoteric surfactants, polyether compounds having polyoxyalkylene chains (and derivatives thereof) And acrylic compounds having a polyoxyalkylene chain (and derivatives thereof) and the like. Moreover, you may mix | blend a polyoxyalkylene chain containing monomer with an acrylic polymer as a polyoxyalkylene chain containing compound. Such polyoxyalkylene chain-containing compounds may be used alone or in combination of two or more.

Specific examples of the polyether compound having a polyoxyalkylene chain include block copolymers of polypropylene glycol (PPG) -polyethylene glycol (PEG), block copolymers of PPG-PEG-PPG, and PEG-PPG-PEG. Examples thereof include block copolymers. Examples of the derivative of the polyether compound having a polyoxyalkylene chain include an oxypropylene group-containing compound having a terminal etherification (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.), an oxypropylene group having a terminal acetylation 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 (meth) 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. Here, the number average molecular weight (Mn) means a value in terms of polystyrene obtained by GPC (gel permeation chromatography).

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

The content of the polyoxyalkylene chain-containing compound not containing the organopolysiloxane can be, for example, 0.005 to 20 parts by mass, preferably 0, with respect to 100 parts by mass of the (meth) acrylic polymer. 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, still more preferably 0.05 to 3 parts by mass, and most preferably 0.1 to 0.9 parts by mass. It is preferable for it to be in the above-mentioned range, since it is easy to achieve both wettability to the adherend and low contamination.

<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 composition 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 compound include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, and fats such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate (IPDI). Aromatic isocyanates such as cyclic isocyanates, 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate (XDI), allophanate bonds, biuret bonds, isocyanurate bonds, uretdione bonds , Urea bond, carbodiimide bond, uretonimine bond, oxadiazinetrione bond Polyisocynate modified products thereof obtained by modifying the. 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 a bifunctional isocyanate compound and a trifunctional or higher functional isocyanate compound are used in combination as the isocyanate compound, 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, from 0.01 to 20 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer used in the acrylic adhesive. The content is preferably 0.1 to 15 parts by mass, 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 crosslinking catalysts include tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonato) iron, tris (hexane-2,4-dionato) iron, and tris (heptane-2,4-dionato). Iron, tris (heptane-3,5-dionato) iron, tris (5-methylhexane-2,4-dionato) iron, tris (octane-2,4-dionato) iron, tris (6-methylheptane-2, 4-Dionato) iron, Tris (2,6-dimethylheptane-3,5-dionato) iron, Tris (nonane-2,4-dionato) iron, Tris (nonane-4,6-dionato) iron, Tris (2 , 2,6,6-tetramethylheptane-3,5-dionato) iron, tris (tridecan-6,8-dionato) iron, tris (1-phenylbutane-1,3) Diato) iron, tris (hexafluoroacetylacetonato) iron, tris (ethyl acetoacetate) iron, tris (acetoacetate-n-propyl) iron, tris (isopropyl acetoacetate) iron, tris (acetoacetate-n-butyl) Iron, tris (acetoacetate-sec-butyl) iron, tris (acetoacetate-tert-butyl) iron, tris (methyl propionylacetate) iron, tris (ethyl propionylacetate) iron, tris (propionylacetate-n-propyl) iron , Tris (propionyl acetate-isopropyl) iron, tris (propionyl acetate-n-butyl) iron, tris (propionyl acetate-sec-butyl) iron, tris (propionyl acetate-tert-butyl) iron, tris (benzyl acetoacetate) iron, Tris (dimethyl malonate) iron, tris (diethyl malonate) iron, trimethoxy iron, Iron-based catalysts such as triethoxy iron, triisopropoxy iron, and ferric chloride can be used. These crosslinking catalysts may be used alone or in combination of two or more.

The content 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 a (meth) acrylic monomer having an alicyclic structure represented by the following general formula as a monomer unit, and when used as an acrylic pressure-sensitive adhesive, It functions as a tackifier resin, improves adhesion, and is effective in suppressing the surface protection film from floating.
CH ₂ = C (R ¹ ) COOR ² [wherein 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, alicyclic carbon such as cyclohexyl group, isobornyl group, dicyclopentanyl group, dicyclopentenyl group, adamantyl group, tricyclopentanyl group, tricyclopentenyl group and the like. A hydrogen group etc. can be mentioned. Examples of 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. Thus, adhesiveness can be improved by giving an acrylic oligomer as a monomer unit a (meth) acrylic monomer having a relatively bulky structure.

The content of the acrylic oligomer is, for example, 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. The content is more preferably 0.2 to 5 parts by mass, and most preferably 0.3 to 2 parts by mass. By using the content within the above range, it is possible to improve the adhesive strength to the adherend and to easily suppress the float, which is a preferable mode.

Further, the pressure-sensitive adhesive composition may contain other known additives, such as powders such as lubricants, colorants, pigments, surfactants, plasticizers, tackifiers, low molecular weights. Polymers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, UV absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils It can be added as appropriate depending on the purpose of using the product.

<Adhesive layer / surface protective film>
The surface protective film of the present invention is formed by forming the pressure-sensitive adhesive layer on the second surface of the base material, and in this case, crosslinking of the pressure-sensitive adhesive composition is 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 1 to 400 μm, more preferably 10 to 200 μm, and most preferably 20 to 100 μm. Within the above range, the adhesive properties (removability, adhesiveness, etc.), workability, and appearance properties are excellent and a preferred embodiment is obtained. In addition, the said total thickness means the sum total of the thickness containing all layers, such as a base material, an adhesive layer, an antistatic 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 has excellent antistatic properties and stability over time of peeling voltage, it can be used for surface protection applications (surface protective film) during processing, transportation, shipping, etc., so 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 those shown in the examples. In the following description and tables, “parts” and “%” are based on mass unless otherwise specified, and indicate solid content or active ingredients.

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)]
[Wherein 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 type of each monomer Represents. ]
Literature values:
2-Ethylhexyl acrylate (2EHA): -70 ° C
n-Butyl acrylate (BA): -55 ° C
2-Hydroxyethyl acrylate (HEA): -15 ° C
4-hydroxybutyl acrylate (HBA): -32 ° C
Acrylic acid (AA): 106 ° C

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

<Measurement of surface resistivity>
Measurement was performed according to 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 / □) in the present invention is preferably 1.0 × 10 both at the initial stage and when left at room temperature (23 ° C. × 50% RH) for 1 week (7 days). ¹¹ or less, more preferably 5.0 × 10 ¹⁰ or less, and still more preferably 1.0 × 10 ¹⁰ or less. 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.

<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. A potential measuring device 40 (model “KSD-0103” manufactured by Kasuga Denki Co., Ltd.) in which the potential of the adherend (polarizing plate) surface generated at this time is fixed at a position 100 mm in height from the center of the polarizing plate 20. The “initial polarizing plate stripping voltage” was measured. The measurement was performed in an environment of 23 ° C. and 50% RH.
Further, after being allowed to stand in an environment of 23 ° C. × 50% RH for 1 week (7 days), the “polarizing plate peeling band voltage with time” was measured in the same manner as the “initial polarizing plate peeling band voltage”. The measurement was performed in an environment of 23 ° C. × 50% RH.
The polarizing plate peeling voltage is a peeling voltage derived from the antistatic layer and the pressure-sensitive adhesive layer constituting the surface protective film of the present invention, and contributes to antistatic properties.
The polarizing plate peeling voltage (kV) (both absolute value, initial and time) in the present invention is preferably 0.8 or less, more preferably 0.7 or less, and still more preferably 0.8. 5 or less. Within the above range, for example, damage to a liquid crystal driver or the like can be prevented, which is a preferable mode.

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

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

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

Hereinafter, a method for preparing samples (surface protective films) of Examples and Comparative Examples will be described.

<Preparation of antistatic layer (1) solution>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and a melamine-based crosslinking agent (as a crosslinking agent) Sumimar M-50W (manufactured by Sumitomo Chemical Co., Ltd.), oleic acid amide as a lubricant, water / ethanol (1/3) mixed solvent, binder in solid content of 100 parts by mass, conductive polymer in solid content of 75 parts by mass Then, 5 parts by mass of the cross-linking agent and 30 parts by mass of the lubricant were added, and the mixture was sufficiently mixed by stirring for about 20 minutes. In this way, an antistatic layer (1) solution having an NV of about 0.4% was prepared (see Table 1).

<Preparation of antistatic layer (2) solution>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, and a melamine-based crosslinking agent (as a crosslinking agent) Sumimar M-50W (manufactured by Sumitomo Chemical Co., Ltd.) in water / ethanol (1/3) mixed solvent, binder is 100 parts by mass in solid content, conductive polymer is 75 parts by mass in solid content, and crosslinking agent is in solid content And 5 parts by mass were added and stirred for about 20 minutes to mix thoroughly. In this way, an antistatic layer (2) solution having an NV of about 0.4% was prepared (see Table 1).

<Preparation of antistatic layer (3) solution>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as the binder, poly (3,4-ethylenedioxythiophene) (PEDOT) 0.5% and polystyrene sulfonate (weight average molecular weight 150,000) as the conductive polymer (PSS) 0.8% aqueous solution (Bytron P, manufactured by HC Stark Co.) in a water / ethanol (1/1) mixed solvent, 100 parts by mass of binder in solid content, and conductive polymer 50 parts by mass of solid content and 5 parts by mass of melamine-based cross-linking agent (Sumimar M-50W, manufactured by Sumitomo Chemical Co., Ltd.) were added and mixed well by stirring for about 20 minutes. In this way, an antistatic layer (3) solution having an NV of about 0.4% was prepared (see Table 1). The obtained antistatic layer (3) solution was visually confirmed for the presence of aggregates.

<Preparation of antistatic layer (4) solution>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, and polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co.) as water / ethanol (1/3) as a conductive polymer 100 parts by mass of the binder and 75 parts by mass of the conductive polymer were added to the mixed solvent, and the mixture was sufficiently mixed by stirring for about 20 minutes. In this way, an antistatic layer (4) solution having an NV of about 0.4% was prepared (see Table 1).

<Preparation of base material with antistatic layer>
On the corona-treated surface of a transparent polyethylene terephthalate (PET) film (polyester film, base material) having a thickness of 38 μm, a width of 30 cm, and a length of 40 cm, on one surface (first surface), the antistatic Any of the liquids for layers (1) to (4) was applied so that the thickness after drying was 30 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.

<Preparation of (meth) acrylic polymer 1 for pressure-sensitive adhesive layer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 95 parts by mass of 2-ethylhexyl acrylate (2EHA), 5 parts by mass of 2-hydroxyethyl acrylate (HEA), 2 as a polymerization initiator , 2'-azobisisobutyronitrile and 0.2 parts by weight of ethyl acetate were charged, nitrogen gas was introduced while gently stirring, and the temperature in the flask was kept at around 65 ° C. for 6 hours. Reaction was performed and the (meth) acrylic-type polymer 1 solution (40 mass%) was prepared. The (meth) acrylic polymer 1 had a weight average molecular weight of 560,000 and a glass transition temperature (Tg) of −68 ° C. (see Table 2).

<Preparation of (meth) acrylic polymers 2 and 3 for the pressure-sensitive adhesive layer>
(Meth) acrylic polymers 2 and 3 were obtained in the same manner as the method for preparing the (meth) acrylic polymer 1 for the pressure-sensitive adhesive layer. In addition, about components other than a monomer component, the same quantity as the (meth) acrylic-type polymer 1 was mix | blended (refer Table 2).

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

[Preparation of acrylic adhesives (2) to (4) solutions]
Acrylic adhesive (2) to (4) solutions were obtained using (meth) acrylic polymers 1 to 3 in the same manner as in the method for preparing the acrylic adhesive (1) solution (see Table 3). .

[Preparation of urethane adhesive (5) 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, “Sanix GP3000” (manufactured by Sanyo Chemical Co., Ltd., Mn, which is a polyol having three hydroxyl groups) = 3000) 13 parts by mass, “Sanix GP1000” which is a polyol having three hydroxyl groups (Sanyo Kasei Co., Ltd., Mn = 1000) 2 parts by mass, isocyanate compound as a crosslinking agent (Coronate HX, manufactured by Nippon Polyurethane) 18 Mass parts, iron (III) acetylacetonate (tris (acetylacetonato) iron) (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 0.04 parts by mass as catalyst, 210 parts by mass of ethyl acetate as diluent solvent, urethane-based adhesive An agent (5) solution was obtained. In addition, as a raw material of a urethane type adhesive solution, all are raw materials with a density | concentration of 100% except a solvent (refer Table 4).

[Preparation of urethane-based adhesive (6) solution]
0.1 part by mass of “KF-6004” (manufactured by Shin-Etsu Chemical Co., Ltd.) as an organosiloxane having an oxyalkylene chain, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (EMIFSI, No. 1) as an antistatic component A urethane-based adhesive (6) solution was obtained in the same manner as the urethane-based adhesive (5) solution, except that 0.3 parts by mass of (Ichi Kogyo Chemical Co., Ltd.) was further added (see Table 4). .

[Preparation of Silicone Adhesive (7) Solution]
As a silicone adhesive, “X-40-3229” (solid content 60% by mass, manufactured by Shin-Etsu Chemical Co., Ltd.) is 100 parts by mass in solid content, and as a platinum catalyst, “CAT-PL-50T” (Shin-Etsu Chemical Co., Ltd.). (Product) 0.5 parts by mass and 100 parts by mass of toluene as a solvent were blended to obtain a silicone-based adhesive (7) solution (see Table 5).

[Preparation of Silicone Adhesive (8) Solution]
“X-40-3229” (solid content 60% by mass, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based adhesive is 100 parts by mass in solid content, and “CAT-PL-50T” (manufactured by Shin-Etsu Chemical Co., Ltd.) as a platinum catalyst. ) 0.5 parts by mass, 0.2 parts by mass of an organosiloxane having an oxyalkylene chain (KF-353, manufactured by Shin-Etsu Chemical Co., Ltd.), lithium bis (trifluoromethanesulfonyl) imide (LiN (CF ₃ SO ₂ ) ₂ : LiTFSI (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.3 parts by mass and 100 parts by mass of toluene as a solvent were blended to obtain a silicone-based adhesive (8) solution (see Table 5).

<Example 1>
<Production of surface protective film>
The acrylic pressure-sensitive adhesive (1) solution was applied to the surface (second surface of the base material) opposite to the antistatic layer of the base material having the antistatic layer (base material with antistatic layer), and 130 ° C. Was heated for 1 minute to form an adhesive layer having a thickness of 15 μm. 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 a silicone treatment on one side, to produce a surface protective film (see Tables 1 to 3 and 6). ).

<Examples 2 to 6 and Comparative Examples 1 to 4>
A surface protective film was produced in the same manner as in Example 1 (see Tables 1 to 3 and 6).

<Example 7>
<Production of surface protective film>
The urethane pressure-sensitive adhesive (5) 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 130 ° C. for 1 minute, A pressure-sensitive adhesive layer having a thickness of 15 μm was formed. Next, the surface of the pressure-sensitive adhesive layer was bonded with a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which is a separator with a silicone treatment on one side, to produce a surface protective film (see Tables 1, 4 and 6). ).

<Example 8>
A surface protective film was produced in the same manner as in Example 9 except that the urethane pressure-sensitive adhesive (6) solution was used (see Tables 1, 4 and 6).

<Example 9>
<Production of surface protective film>
The silicone-based pressure-sensitive adhesive (7) solution was applied to the surface opposite to the antistatic layer of the substrate having the antistatic layer (substrate with antistatic layer), heated at 150 ° C. for 1 minute, A pressure-sensitive adhesive layer having a thickness of 15 μm was formed. Next, the surface of the pressure-sensitive adhesive layer was bonded with a silicone-treated surface of a polyethylene terephthalate film (thickness 25 μm), which is a separator having one surface subjected to fluorine treatment, to produce a surface protective film (see Tables 1, 5 and 6). ).

<Example 10>
A surface protective film was produced in the same manner as in Example 9 except that the silicone-based pressure-sensitive adhesive (8) solution was used (see Tables 1, 5 and 6).

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 Tables 2 to 5 will be described below. Abbreviations in other tables are based on examples and comparative examples.
[Monomer component]
2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate HEA: 2-hydroxyethyl acrylate HBA: 4-hydroxybutyl acrylate AA: acrylic acid

[Organopolysiloxane]
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.)

[Polyether component]
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%)

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

From the evaluation results in Table 6 above, in all examples, the antistatic property due to the antistatic layer, the stability over time of the stripping voltage (surface resistivity and film side stripping voltage), and excellent print adhesion Was confirmed. Further, in the examples using the lubricant when forming the antistatic layer, the slipping property is also excellent, and in the examples using the antistatic component when forming the adhesive layer, the antistatic property (polarizing plate) is used. It was confirmed that the stripping voltage was also excellent.

On the other hand, in the comparative example, since the antistatic layer is not formed with the desired antistatic agent composition, the antistatic property due to the antistatic layer and the stability over time of the peeling band voltage are obtained from the evaluation results in Table 6 above. Further, none satisfying all the characteristics of the printing adhesiveness was obtained.

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 an adhesive formed on the second surface of the base material using an adhesive composition A surface protective film comprising an agent layer,
The antistatic layer is formed using an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and a melamine-based crosslinking agent as a crosslinking agent. Surface protection film.
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 as described in 2.
The surface protection film according to claim 1 or 2, 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.
5. The surface protective film according to claim 1, wherein the pressure-sensitive adhesive composition contains an antistatic component.
An optical member that is protected by the surface protective film according to any one of claims 1 to 5.
A method for producing a surface protective film according to any one of claims 1 to 5,
A step of preparing an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and a melamine-based crosslinking agent as a crosslinking agent;
Applying and drying the antistatic agent composition on the first surface of the base material to prepare an antistatic layer, and a method for producing a surface protective film.