KR20160063987A - Surface protective film, method for manufacturing surface protective film and optical member - Google Patents

Abstract

A surface protective film for a touch panel which is excellent in antistatic property and long-term stability of the peeling electrification voltage, can confirm the operation of the touch panel and also has excellent wettability with respect to the interlayer filler on the surface of the adherend after peeling off the surface protective film, A method for producing the surface protective film, and an optical member. A surface protective film for a touch panel of the present invention comprises a substrate having a first surface and a second surface; an antistatic layer formed on the first surface of the substrate; and a pressure-sensitive adhesive Wherein the antistatic layer is formed of an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent, and the pressure- ) Acrylic polymer and a polyether compound, wherein the polyether compound is contained in an amount of 0.03 to 14 parts by mass based on 100 parts by mass of the (meth) acryl-based polymer.

Description

TECHNICAL FIELD [0001] The present invention relates to a surface protective film, a method of manufacturing a surface protective film,

The present invention relates to a surface protective film for a touch panel, a method for manufacturing the surface protective film, and an optical member mounted on the touch panel.

The surface protective film generally has a constitution in which a pressure-sensitive adhesive layer is formed on a film-like base material (support). Such a protective film is bonded to an adherend (to-be-protected) through the pressure-sensitive adhesive layer, thereby protecting the adherend from scratches and contamination during processing and transportation.

For example, a touch 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 through a pressure sensitive adhesive layer. In the manufacture of such a liquid crystal display panel, a polarizing plate bonded to a liquid crystal cell is once formed into a roll form, then cut out from the roll and cut to a desired size according to the shape of the liquid crystal cell. In order to prevent the polarizing plate from interfering with the transfer roll or the like in the intermediate process, it is necessary to bond the surface protective film to one side or both sides (typically, one side) of the polarizing plate.

Generally, since the surface protective film or the optical member is made of a plastic material, the electrical insulation is high, and static electricity is generated by friction or peeling. As a result, when a surface protective film is peeled off from an optical member such as a polarizing plate, static electricity tends to easily be generated. When a voltage is applied to the liquid crystal while the static electricity remains, the orientation of the liquid crystal molecules is lost, There is a risk that In addition, the presence of static electricity may also be a factor of sucking dust and deteriorating workability. In such circumstances, antistatic treatment is performed on the surface protective film. For example, by forming an antistatic layer or forming an antistatic coating on the surface layer (top coat layer and back layer) of the surface protective film, (See Patent Documents 1 and 2).

In recent years, PEDOT (poly (3,4-ethylenedioxythiophene) / PSS (polystyrenesulfonate) (polythiophene type) as a conductive polymer used for imparting an antistatic function to a surface layer of a surface protective film, However, when the aqueous dispersion type is stored in a solution state, agglomerates are generated and a uniform antistatic layer can not be formed, resulting in a problem of poor workability. When an antistatic layer is formed by using a conductive polymer, PSS (corresponding to a dopant) is released from the PEDOT with the lapse of time, and surface resistance and peeling electrification voltage are increased, and oxidation deterioration and photo deterioration (Deterioration) of the surface resistance value accompanied with the increase of the surface resistance.

On the other hand, when the polarizing plate is provided on the viewer side from the touch sensor in the capacitive touch panel, when the operation of the touch panel is confirmed with the protective film attached to the polarizing plate, the surface resistance value Is too low, the touch panel does not react and the inspection can not be performed. When the surface resistance value is too high, static electricity is generated, which may cause a problem.

Further, at the stage where the surface protective film is unnecessary, a layer (another layer) having another function or the like may be formed on the surface of the adherend to which the surface protective film has been adhered after peeling from the optical member. Depending on the state of the surface of the adherend after the surface protective film is peeled off, the wettability of the other layer may deteriorate. If the other layer fails to exhibit the expected function or the product becomes poor do. Specifically, when a different layer such as a layer having a touch panel function is formed on the surface of the polarizing plate, the surface protective film formed to protect the surface of the polarizing plate (e.g., a polarizing plate whose surface layer is a hard coating layer) , When the interlayer filler is applied between the other layer and the polarizing plate surface to form a transparent layer, the wettability to the interlayer filler on the surface of the polarizing plate may not be sufficient. Therefore, development of a surface protective film capable of ensuring a state of excellent wettability when another layer is formed on the surface of the adherend after peeling off the surface protective film is required.

Japanese Patent Application Laid-Open No. 2004-223923 Japanese Patent Application Laid-Open No. 2008-255332

Accordingly, the present invention has been made in view of the above circumstances, and as a result, it has been found that the antistatic property and the peeling electrification voltage are excellent in stability over time and that the operation of the touch panel can be confirmed, A surface protective film for a touch panel, a method for producing the surface protective film, and an optical member.

That is, the surface protection film for a touch panel of the present invention comprises: a substrate having a first surface and a second surface; an antistatic layer formed on the first surface of the substrate; and an antistatic layer formed on the second surface of the substrate by a pressure- Wherein the antistatic layer is formed of an antistatic agent composition containing a polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate based crosslinking agent as a crosslinking agent, and the pressure- (Meth) acrylic polymer and a polyether compound, wherein the polyether compound is contained in an amount of 0.03 to 14 parts by mass based on 100 parts by mass of the (meth) acryl-based polymer.

In the surface protective film for a touch panel of the present invention, it is preferable that the substrate contains polyethylene terephthalate and / or polyethylene naphthalate.

In the surface protective film for a touch panel of the present invention, it is preferable that the antistatic agent composition further contains a fatty acid amide as a lubricant.

In the surface protective film for a touch panel of the present invention, it is preferable that the polyether compound is a surfactant.

The optical member mounted on the touch panel of the present invention is preferably protected by the surface protection film for the touch panel.

The method for producing a surface protective film for a touch panel of the present invention comprises the steps of preparing an aqueous solution containing the antistatic agent composition and applying the aqueous solution to the first surface of the substrate and drying to prepare an antistatic layer .

The surface protective film of the present invention is characterized in that the antistatic layer is formed of an antistatic agent composition containing a specific conductive polymer component, a binder and a crosslinking agent, whereby a uniform antistatic layer can be formed and workability is excellent, Sensitive adhesive composition comprising a pressure-sensitive adhesive layer containing a (meth) acrylic polymer and a polyether compound in a specific ratio, wherein the pressure-sensitive adhesive layer is excellent in antistatic property based on the pressure- Even when the surface protecting film attached to an adherend such as a polarizing plate is peeled and the interlayer filler is applied to the same adherend surface, the surface protective film for a touch panel excellent in wettability to the interlayer filler, And an optical member can be obtained, resulting in a preferable form.

1 is a schematic cross-sectional view showing a configuration example of a surface protective film for a touch panel according to the present invention.
2 is a schematic cross-sectional view showing a structural example of a touch panel to which a surface protective film for a touch panel of the present invention is attached.
3 is an explanatory view showing a method of measuring the peeling electrification voltage.

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

<Overall Structure of Surface Protective Film for Touch Panel>

The surface protective film for a touch panel (hereinafter sometimes simply referred to as a &quot; surface protective film &quot;) disclosed herein is generally in the form of an adhesive sheet, an adhesive tape, an adhesive label, an adhesive film, And is particularly suitable as a surface protective film for protecting the surface of an optical member during processing or transportation of an optical member such as a polarizing plate attached to a touch sensor in a liquid crystal display panel or a glass through a pressure sensitive adhesive layer. The pressure-sensitive adhesive layer in the surface protective film is typically formed continuously, but the pressure-sensitive adhesive layer is not limited to this, and may be a pressure-sensitive adhesive layer formed in a regular or random pattern such as a point shape or a stripe shape. The surface protective film disclosed herein may be in the form of a roll or a sheet.

A typical configuration example of the surface protective film disclosed here is schematically shown in Figs. 1 and 2. Fig. This surface protective film 1 comprises a substrate 12 (for example, a polyester film) 12, an antistatic layer 11 formed on the first surface 12, and a second surface And a pressure-sensitive adhesive layer 13 formed on the surface opposite to the barrier layer 11. The surface protective film 1 is formed by laminating the pressure sensitive adhesive layer 13 on the touch sensor 32 or the base glass 33 in the liquid crystal display panel (touch panel) 3 as an adherend The surface of the optical member such as the polarizing plate 31 which is interposed therebetween). The surface protective film 1 before use (that is, before adhering to an adherend) is peeled off at least on the surface of the pressure-sensitive adhesive layer 13 (adhered surface to the adherend) Or may be in a form protected by a liner. Alternatively, the surface protective film 1 may be rolled so that the pressure sensitive adhesive layer 13 is in contact with the back surface (the surface of the antistatic layer 11) of the substrate 12 to protect the surface thereof.

1, an antistatic layer 11 is formed directly on the first surface of the substrate 12 (without interposing another layer), and the antistatic layer 11 is formed on the back surface of the surface protective film 1 The antistatic layer 11 having the antistatic layer 11 formed on the base 12 has a structure in which the antistatic layer 11 is formed on the base 12 in a manner that the antistatic layer 11 is formed separately from the top coating layer (Further, the surface protective film formed using the film) can be reduced in the number of layers constituting the surface protective film, and therefore, is also advantageous from the viewpoint of productivity improvement and the like.

<Description>

The surface protective film of the present invention is characterized by having a substrate having a first surface (back surface) and a second surface (surface opposite to the first surface). In the techniques disclosed herein, the resin material constituting the base material can be used without particular limitation, and for example, it is possible to use a resin material having excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, flexibility and dimensional stability . In particular, since the base material has flexibility, the pressure-sensitive adhesive composition can be coated by a roll coater or the like, and the film can be wound in a roll form, which is useful.

Examples of the substrate (support) include polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; Cellulose-based polymers such as diacetylcellulose and triacetylcellulose; Polycarbonate-based polymers; Acrylic polymers such as polymethyl methacrylate; Or the like as a main resin component (a main component in a resin component, typically a component occupying 50 mass% or more) can be preferably used as the above-mentioned base material. Other examples of the resin material include styrene polymers such as polystyrene and acrylonitrile-styrene copolymer; Olefin polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers; Vinyl chloride polymers; Amide polymers such as nylon 6, nylon 6,6, and aromatic polyamides; And the like as a resin material. As another example of the resin material, there may be mentioned imide polymers, sulfone polymers, polyether sulfone polymers, polyether ether ketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl A butyral polymer, an arylate polymer, a polyoxymethylene polymer, and an epoxy polymer. Or a substrate comprising two or more of the above-mentioned polymers.

As the substrate, a plastic film containing a transparent thermoplastic resin material can be preferably employed. Of the above plastic films, a polyester film is more preferably used. Here, the polyester film refers to a polymer material (polyester resin) based on an ester bond such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polybutylene terephthalate as a main resin component . Such a polyester film is excellent in optical properties and dimensional stability, and has desirable properties as a base material for a surface protective film. Among them, it is particularly preferable to contain polyethylene terephthalate and / or polyethylene naphthalate as the base material.

Various additives such as antioxidants, ultraviolet absorbers, plasticizers, coloring agents (pigments, dyes, etc.) may be added to the resin material constituting the base material, if necessary. The first side (the surface on the side where the antistatic layer is formed) of the polyester film is subjected to a known or tolerable treatment such as corona discharge treatment, plasma treatment, ultraviolet ray irradiation treatment, acid treatment, alkali treatment, May be subjected to surface treatment. Such a surface treatment may be, for example, a treatment for enhancing the adhesion between the substrate and the antistatic layer. A surface treatment such as introduction of a polar group such as a hydroxyl group onto the surface of the substrate can be preferably employed. Further, the same surface treatment as described above may be applied to the second surface (the surface of the side on which the pressure-sensitive adhesive layer is formed) of the substrate. Such a surface treatment may be a treatment for enhancing adhesion between the film and the pressure-sensitive adhesive layer (permeability 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 made of antistatic treatment as the base material. The use of the above-described substrate is preferable because the charging of the surface protective film itself upon peeling is suppressed. In addition, the substrate is a plastic film, and the plastic film is subjected to the antistatic treatment to reduce the electrification of the surface protective film itself, and to obtain an excellent antistatic property to the adherend. The method for imparting the antistatic function is not particularly limited and conventionally known methods can be used. For example, an antistatic resin or a conductive polymer containing an antistatic agent and a resin component, a conductive A method of applying a resin, a method of vapor-depositing or plating a conductive material, a method of superposing an antistatic agent or the like, and the like.

The thickness of the substrate is usually about 5 to 200 占 퐉, preferably about 10 to 100 占 퐉. When the thickness of the base material is within the above range, bonding workability to the adherend and peeling workability from the adherend are excellent.

&Lt; Antistatic Layer (Top Coating Layer) >

The surface protective film of the present invention comprises a substrate having a first side (back side) and a second side (opposite side to the first side), an antistatic layer formed on the first side (back side) of the substrate, Wherein the antistatic layer comprises a polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent, wherein the antistatic layer comprises an antistatic agent composition comprising Is formed. When the surface protective film has an antistatic layer (top coating layer), the antistatic property of the surface protective film and the stability with time of the peeling electrification voltage are improved, which is a preferable form.

&Lt; Conductive polymer &

The antistatic layer is characterized by containing polyaniline sulfonic acid as a conductive polymer component. By using the conductive polymer, the antistatic property based on the antistatic layer and the peeling electrification voltage with time can be satisfied. The polyaniline sulfonic acid is "water-soluble", but it can be immobilized in the antistatic layer by using an isocyanate-based crosslinking agent to be described later, and water resistance can be improved. By using the above-mentioned water-soluble conductive polymer-containing aqueous solution, an antistatic layer having an excellent surface resistance value with time can be obtained, which is a preferable form. On the other hand, when the electroconductive polymer used for forming the antistatic layer is &quot; water-dispersible &quot;, if the electroconductive polymer-containing solution is used to form an antistatic layer, aggregates tend to be generated, , The surface resistance value with time tends to remarkably decrease, which is not preferable.

The amount of the conductive polymer to be used is preferably 10 to 200 parts by mass, more preferably 25 to 150 parts by mass, and still more preferably 40 to 120 parts by mass with respect to 100 parts by mass of the binder contained in the antistatic layer. If the amount of the conductive polymer used is too small, the antistatic effect may be small. If the amount of the conductive polymer is too large, the adhesion of the antistatic layer to the base material may deteriorate or transparency may deteriorate.

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

As a method of forming the antistatic layer, a method of applying a coating material (antistatic agent composition) for forming an antistatic layer onto the first surface of a substrate (support) and drying (or curing) the coating may be adopted. As the conductive polymer component, polyaniline sulfonic acid, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent are included as essential components, and those in which the essential components are dissolved in water (conductive polymer aqueous solution or simply aqueous solution) Can be used. Such a conductive polymer aqueous solution can be prepared, for example, by dissolving a conductive polymer having a hydrophilic functional group (which can be synthesized by a method such as copolymerizing a monomer having a hydrophilic functional group in the molecule) in water. Examples of the hydrophilic functional groups include sulfo groups, amino groups, amide groups, imino groups, hydroxyl groups, mercapto groups, hydrazino groups, carboxyl groups, quaternary ammonium groups, sulfuric acid ester groups (-O-SO ₃ H) For example, -O-PO (OH) ₂ ) and the like are exemplified. Such a hydrophilic functional group may form a salt.

As a commercially available product of the aqueous solution of polyaniline sulfonic acid, "aqua-PASS" manufactured by Mitsubishi Rayon Co., Ltd. and the like are exemplified.

The antistatic layer disclosed herein contains, as an electrically conductive polymer component, polyaniline sulfonic acid (polyaniline type) as an essential component. For example, the antistatic layer may contain one or more other antistatic components (an organic conductive material other than the conductive polymer, A conductive material, an antistatic agent, etc.). As a preferred form, it is preferable that the antistatic layer substantially contains no antistatic component other than the conductive polymer, that is, the antistatic component contained in the antistatic layer contains substantially only the conductive polymer .

Examples of the organic conductive material include a cationic antistatic agent having a cationic functional group such as a quaternary ammonium salt, a pyridinium salt, a primary amino group, a secondary amino group, or a tertiary amino group; Anionic antistatic agents having anionic functional groups such as sulfonic acid salts, sulfuric acid ester salts, phosphonic acid salts and phosphoric acid ester salts; Amphoteric antistatic agents such as alkyl betaines and derivatives thereof, imidazolines and derivatives thereof, alanines and derivatives thereof; Nonionic type antistatic agents such as amino alcohols and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof; An ion-conductive polymer obtained by polymerizing or copolymerizing a monomer having an ion-conductive group (for example, a quaternary ammonium salt group) of the cationic, anionic, or positive ionic type; And conductive polymers such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine-based polymers. These antistatic agents may be used alone or in combination of two or more.

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, copper iodide, ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide), and the like. These inorganic conductive substances may be used singly or in combination of two or more kinds.

Examples of the antistatic agent include a cationic antistatic agent, an anionic antistatic agent, a positive ionic type antistatic agent, a nonionic antistatic agent, and an ionic conductive agent obtained by polymerizing or copolymerizing a monomer having an ionic conductive group of the above cationic, anionic, Polymers and the like.

<Binder>

The antistatic layer is characterized by containing, as an essential component, a polyester resin as a binder. The polyester resin is preferably a resin material containing a polyester as a main component (typically, more than 50 mass%, preferably 75 mass% or more, for example, 90 mass% or more). The polyester is typically prepared from polyvalent carboxylic acids (typically, dicarboxylic acids) having two or more carboxyl groups in one molecule and derivatives thereof (anhydrides, esters, halides, etc. of the polyvalent carboxylic acids) One or two or more compounds selected from one or more compounds (polyvalent carboxylic acid component) selected from polyvalent alcohols having two or more hydroxyl groups in one molecule (typically, diols) And a polyhydric alcohol component) condensed with each other.

Examples of compounds usable as the polyvalent carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±) But are not limited to, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, Methyl adipic acid, dimethyadipic acid, tetramethyladipic acid, methylene adipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6- Aliphatic dicarboxylic acids such as tetramethylsuburic acid, azelaic acid, sebacic acid, perfluorosevacic acid, brassylic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid and tetradecyldicarboxylic acid; Cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4- (2-norbornene) dicarboxylic acid, 5-cyclohexanedicarboxylic acid, Alicyclic dicarboxylic acids such as norbornene-2,3-dicarboxylic acid (heme acid), adamantanedicarboxylic acid and spiroheptanedicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, There may be mentioned acid anhydrides such as methyl isophthalic acid, dimethyl isophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalene dicarboxylic acid, oxofluorene dicarboxylic acid, , Biphenyldicarboxylic acid, biphenylene dicarboxylic acid, dimethyl biphenylene dicarboxylic acid, 4,4'-p-terphenylenedicarboxylic acid, 4,4'-p-guarylphenyl Dicarboxylic acid, bibenzyldicarboxylic acid, azobenzene dicarboxylic acid, homophthalic acid, phenyl Specific examples of the polyfunctional acid anhydrides include phenol diacetic acid, phenylene dicarboxylic acid, naphthalene dicarboxylic acid, naphthalene dicopropionic acid, biphenyl diacetic acid, biphenyl dicopropionic acid, 3,3 '- [ Aromatic dicarboxylic acids such as dicopropionic acid, 4,4'-bibenzyl diacetic acid, 3,3 '(4,4'-bibenzyl) dicopropionic acid, and oxydi-p-phenylene diacetic acid; An acid anhydride of a polycarboxylic acid, an ester of a polycarboxylic acid of any of the above (which may be, for example, an alkyl ester, a monoester, a diester, etc.), an acid halide corresponding to a polyvalent carboxylic acid (For example, dicarboxylic acid chloride), and the like.

Suitable examples of the compound usable as the polyvalent carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid, and acid anhydrides thereof; Aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, hemeic acid and 1,4-cyclohexanedicarboxylic acid, and acid anhydrides thereof; And lower alkyl esters of the dicarboxylic acids (for example, esters with monoalcohols having 1 to 3 carbon atoms).

Examples of the compound 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, neopentyl glycol , 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl- Diols such as 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A, . Other examples include alkylene oxide adducts of these compounds (e.g., ethylene oxide adduct, propylene oxide adduct, etc.).

The molecular weight of the polyester resin is a weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography (GPC), for example, about 5 × 10 ³ to 1.5 × 10 ⁵ (preferably 1 × 10 ⁴ to 6 x 10 ⁴ ). The glass transition temperature (Tg) of the polyester resin may be, for example, 0 to 120 캜 (preferably 10 to 80 캜).

As the polyester resin, a trade name &quot; Vylonal &quot; available from Toyobo Co., Ltd. or the like may be used.

The antistatic layer (top coating layer) may be a resin other than the polyester resin (for example, a resin other than the polyester resin) as the binder, as long as it does not significantly impair the performance of the surface protective film (for example, One or more resins selected from acrylic resin, acrylic urethane resin, acrylic styrene resin, acrylic silicone resin, silicone resin, polysilazane resin, polyurethane resin, fluorine resin and polyolefin resin) . One preferred form of the technique disclosed herein is the case where the binder of the antistatic layer contains substantially only polyester. For example, an antistatic layer in which the ratio of the polyester resin to the binder is 98 to 100% by mass is preferable. The proportion of the binder in the entire antistatic layer can be, for example, 50 to 95 mass%, and is usually 60 to 90 mass%.

<Lubricant>

The antistatic layer (top coating layer) in the technique disclosed here is a preferred form of using a fatty acid amide as a lubricant. Even in a form in which the surface of the antistatic layer is not subjected to a new peeling treatment (for example, a treatment for applying and drying a known peeling agent such as a silicone-based releasing agent and a long-chain alkyl-based releasing agent) by using a fatty acid amide as the lubricant, It is possible to obtain an antistatic layer (top coating layer) that combines both slidability and affinity for the ink, which is a preferable form. The form in which the surface of the antistatic layer is not subjected to the new peeling treatment is preferable in view of being able to prevent whitening due to the peeling treatment agent (for example, whitening by preservation under the heating and humidifying conditions) Do. It is also advantageous in terms of solvent resistance.

Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, N-oleyl palmitic acid amide, N- Stearyl stearamide, stearyl stearamide, stearyl stearamide, N-stearyl oleamide, N-oleyl stearamide, N-stearyl erucic acid amide, methylol stearamide, methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylene Hexamethylenebishebic acid amide, hexamethylene hydroxystearic acid amide, N, N'-dicyclohexylmethane diisocyanate, ethylenebis (hydroxystearic acid) amide, ethylenebis (hydroxystearic acid) amide, N'-distearyl adipic acid amide, N, N'-distearyl sebacic acid amide, ethylene bis-oleic acid amide, Ethylenebiserythroate, ethylenebiseryth acid amide, hexamethylenebisoleic acid amide, N, N'-dioleyladipic acid amide, N, N'-dioleylsebasic acid amide, m-xylylenebisstearic acid amide, m- N, N'-stearyl isophthalic acid amide, and the like. These lubricants may be used singly or in combination of two or more kinds.

The proportion of the lubricant in the whole antistatic layer may be 1 to 50% by mass, and usually 5 to 40% by mass. If the content of the lubricant is too small, the slidability tends to be lowered. If the content of the lubricant is too large, the pressure-sensitive adhesiveness may deteriorate.

The technique disclosed herein can be carried out in the form of an antistatic layer (top coating layer) containing, in addition to the fatty acid amide, other lubricants, so long as the effect of the application is not significantly impaired. Examples of such other lubricants include various waxes such as petroleum wax (paraffin wax and the like), mineral wax (montan wax and the like), higher fatty acid (such as chitosan) and neutral fat (palmitic acid triglyceride and the like) . Or, in addition to the wax, general silicone lubricants, fluorine lubricants and the like may be supplementarily contained. The techniques disclosed herein can be suitably practiced in a form substantially free of such silicone-based lubricants, fluorine-containing lubricants, and the like. However, it is preferable to exclude the use of a silicon-based compound used for other purposes than the lubricant (for example, as a defoaming agent for a coating material for forming an antistatic layer to be described later) so long as it does not significantly impair the application effect of the technique disclosed herein no.

<Cross-linking agent>

The antistatic layer contains an isocyanate-based crosslinking agent as a crosslinking agent. By using the isocyanate crosslinking agent, the water-soluble polyaniline sulfonic acid, which is an essential component in forming the antistatic layer, can be immobilized in the binder, the water resistance can be improved, and the effect of improving the adhesion of the ink can be realized.

As the isocyanate-based cross-linking agent, it is preferable to use a blocked isocyanate-based cross-linking agent that is stable in aqueous solution. Specific examples of the blocked isocyanate-based crosslinking agent include an isocyanate-based crosslinking agent (for example, an isocyanate compound (isocyanate-based crosslinking agent) used in a pressure-sensitive adhesive layer described later) that can be used at the time of preparing a general adhesive layer or an antistatic layer And the like can be used which are blocked with alcohols, phenols, thiophenols, amines, imides, oximes, lactams, active methylene compounds, mercaptans, imines, ureas, diaryl compounds and sodium bisulfite.

The antistatic layer in the techniques disclosed herein may be used in combination with other antistatic components, antioxidants, colorants (pigments, dyes, etc.), flowability adjusters (thixotropic agents, thickeners, etc.), coagulation aids, surfactants ), Preservatives, and the like.

&Lt; Formation of antistatic layer >

The antistatic layer (top coating layer) is provided with a liquid composition (a coating material for forming an antistatic layer, an antistatic agent composition) in which essential components such as the above-mentioned conductive polymer component and additives used as needed are dissolved in a suitable solvent , And the like. For example, a method of applying the coating material to the first surface of the base material, followed by drying, and optionally curing (heat treatment, ultraviolet ray treatment, etc.) may be employed. The NV (nonvolatile content) of the coating material may be, for example, 5 mass% or less (typically 0.05 to 5 mass%) and usually 1 mass% or less (typically 0.10 to 1 mass% It is appropriate. In the case of forming the antistatic layer with a small thickness, it is preferable that NV of the coating material is 0.05 to 0.50 mass% (for example, 0.10 to 0.40 mass%). By using such a low NV coating material, a more uniform antistatic layer can be formed.

As the solvent constituting the coating material for forming the antistatic layer, it is preferable that the antistatic layer can stably dissolve the forming component. Such a solvent may be an organic solvent, water or a mixture 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 hydrocarbons such as n-hexane and cyclohexane; Aromatic hydrocarbons such as toluene and xylene; Aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, and cyclohexanol; And glycol ethers such as alkylene glycol monoalkyl ethers (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) and dialkylene glycol monoalkyl ethers; and the like can be used . In a preferred form, the solvent of the coating material is a water or a water-based mixed solvent (for example, a mixed solvent of water and ethanol).

&Lt; Characteristics of Antistatic Layer >

The thickness of the antistatic layer in the techniques disclosed herein is typically 3 to 500 nm, preferably 3 to 100 nm, more preferably 3 to 60 nm. When the thickness of the antistatic layer is too small, it is difficult to uniformly form the antistatic layer (for example, the thickness of the antistatic layer varies from place to place) There is a possibility that this may occur easily. On the other hand, if it is too thick, the properties (optical characteristics, dimensional stability, etc.) of the substrate may be affected.

In one preferred form of the surface protective film disclosed herein, the surface resistance (Ω / □) measured on the surface of the antistatic layer is preferably 1.0 × 10 ⁷ or more and less than 1.0 × 10 ¹¹ , , And not less than 1.0 × 10 ⁸ and less than 5.0 × 10 ¹⁰ , and further preferably not less than 1.0 × 10 ⁹ and less than 2.0 × 10 ¹⁰ . The surface protective film exhibiting the surface resistance value within the above range can be suitably used as a surface protective film used in, for example, processing or transporting articles such as a liquid crystal cell, a semiconductor device and the like, which are disliked with static electricity. The surface protective film exhibiting the surface resistance value within the above range can be confirmed to be operable even when the polarizing plate is mounted above the touch panel sensor and the surface protective film is attached on the polarizing plate. The surface resistance value can be calculated from the surface resistance value measured at 23 캜 and 50% RH using a commercially available insulation resistance measuring apparatus.

It is preferable that the surface protective film disclosed herein has such a property that the back surface (the surface of the antistatic layer) can easily be printed with water-based inks or oil-based inks (for example, using an oil-based marking pen). Such a surface protective film may be formed by bonding an identification number of an adherend to be protected and the like to the surface protective film (for example, an optical member such as a polarizing plate) Is also suitable for displaying on the display. Therefore, it is preferable that the surface protective film is excellent in printability. For example, it is preferable that the solvent has an alcohol-based, oil-repellent type ink containing a high coloring property. Further, it is preferable that the printed ink is hard to be dropped by friction or electrodeposition (that is, excellent in the adhesion of the ink). The surface protective film disclosed herein also preferably has a solvent resistance to such an extent that no significant change in appearance occurs even when the factor is wiped with an alcohol (for example, ethyl alcohol) at the time of modifying or erasing the factor.

The surface protective film disclosed herein can be also applied in the form of containing another layer besides the base material, the pressure-sensitive adhesive layer and the antistatic layer. Examples of the arrangement of the "other layer" include between the first surface (back surface) of the substrate and the antistatic layer, between the second surface (front surface) of the substrate and the pressure-sensitive adhesive layer, and the like. The layer disposed between the substrate back surface and the antistatic layer may be, for example, a layer containing an antistatic component (the antistatic layer described above). The layer disposed between the front side of the substrate and the pressure-sensitive adhesive layer may be, for example, a lower layer (anchor layer), an antistatic layer, or the like for enhancing the permeability of the pressure-sensitive adhesive layer to the second surface. The surface protective film may be a structure in which an antistatic layer is disposed on the front surface of the substrate, an anchor layer is disposed on the antistatic layer, and a pressure-sensitive adhesive layer is disposed thereon.

<Pressure-sensitive adhesive layer>

The surface protective film of the present invention has the above pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition contains a (meth) acrylic polymer and a polyether compound, Of the polyether compound in an amount of 0.03 to 14 parts by mass.

The (meth) acrylic polymer may be a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms as a raw material monomer constituting the (meth) acrylic polymer. As the (meth) acrylic monomer, one or more of them may 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 adhesion force to an adherend (to-be-protected) to a low level, and a surface protective film excellent in light- . The (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer, and (meth) acrylate refers to acrylate and / or methacrylate.

Specific examples of the (meth) acrylic monomers having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, Acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (Meth) acrylate, n-decyl (meth) acrylate, n-octyl (meth) acrylate, -Tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate.

Among them, the surface protective film of the present invention is preferably a film obtained by copolymerizing at least one selected from the group consisting of hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, N-decyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, (Meth) acrylate monomer having an alkyl group having 6 to 14 carbon atoms such as tetradecyl (meth) acrylate. In particular, by using a (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms, it is easy to control the adhesive force to an adherend and the re-peeling property is excellent.

In particular, the (meth) acrylic polymer preferably contains 50 mass% or more of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms relative to 100 mass% of the total amount of the monomer components, more preferably 60 mass% More preferably 70% by mass or more, and particularly preferably 80 to 93% by mass. When the content is less than 50% by mass, the appropriate wettability of the pressure-sensitive adhesive composition and the cohesive force of the pressure-sensitive adhesive layer are deteriorated.

In addition, the pressure-sensitive adhesive composition of the present invention preferably contains the (meth) acrylic monomer having a hydroxyl group as the raw monomer as the (meth) acrylic polymer. As the (meth) acrylic monomers having a hydroxyl group, one or more of them can be used as a main component.

By using the (meth) acrylic monomer having a hydroxyl group, crosslinking and the like of the pressure-sensitive adhesive composition can be easily controlled, and the balance between improvement in wettability due to flow and reduction in adhesion in peeling becomes easy to control. In addition, since the hydroxyl group has an appropriate interaction when an ionic compound or the like is used as an antistatic component, the antistatic property is different from the carboxyl group or the sulfonate group which can act as a crosslinking site in general , And 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, 12-hydroxybutyl (meth) acrylate, 8-hydroxybutyl (meth) acrylate, Cyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, and the like. In particular, the use of a (meth) acrylic monomer having a hydroxyl group with an alkyl group having 4 or more carbon atoms is preferable since delamination at high-speed peeling becomes easy.

It is preferable that the (meth) acrylic monomer having a hydroxyl group is contained in an amount of 15 parts by mass or less, more preferably 1 to 13 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 More preferably 2 to 11 parts by mass, and most preferably 3.5 to 10 parts by mass. Within this range, it is preferable to control the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the resulting pressure-sensitive adhesive layer.

Further, as other polymerizable monomer components, the glass transition temperature and the peelability of the (meth) acryl-based polymer are adjusted so that the Tg becomes 0 deg. C or lower (usually -100 deg. C or higher) And the like can be used within a range that does not impair the effect of the present invention.

Examples of other polymerizable monomers 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, which are used in the (meth) acrylic polymer, include (meth) Acrylic monomers can be used.

Examples of the (meth) acrylic monomers having a carboxyl group include (meth) acrylic acid, carboxylethyl (meth) acrylate, and carboxypentyl (meth) acrylate.

The (meth) acrylic monomer having a carboxyl group is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and more preferably 1 part by mass or less, based on 100 parts by mass of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms By mass, and most preferably 0.005 to 0.5 part by mass. When more than 5 parts by mass, a large number of acid functional groups such as a carboxyl group having a high polarity action are present. For example, when an ionic compound is added as an antistatic component, an acid functional group such as a carboxyl group interacts The ion conduction can be hindered and the conductive efficiency is lowered, and sufficient antistatic properties can not be obtained, which is not preferable.

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, which are used in the (meth) acrylic polymer, The monomer is not particularly limited as long as it does not impair the properties of the present invention. For example, a cohesive force / heat resistance improving component such as a cyano group-containing monomer, a vinyl ester monomer, and an aromatic vinyl monomer, an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, an epoxy group- , A vinyl ether monomer or the like can be suitably used as the component having a functional group which functions as an adhesive force improving or crosslinking starting point. These polymerizable monomers may be used alone or in combination of two or more.

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

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

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

Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, diacetone acrylamide, etc. .

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

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

Examples of the 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 (meth) acrylic monomers having an alkyl group of 1 to 14 carbon atoms, (meth) acrylic monomers having a hydroxyl group, and (meth) acrylic monomers having a carboxyl group, Is preferably 0 to 20 parts by mass, more preferably 0 to 10 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. When the ionic compound is used as the antistatic agent by using the above other polymerizable monomer within the above range, good interaction with the ionic compound and good releasability can be appropriately controlled.

The (meth) acrylic polymer preferably has a weight average molecular weight (Mw) of 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, and still more preferably 300,000 to 3,000,000. When the weight-average molecular weight is less than 100,000, the cohesive force of the pressure-sensitive adhesive layer is decreased, and the pressure-sensitive adhesive tends to remain. On the other hand, when the weight average molecular weight exceeds 500,000, the fluidity of the polymer is lowered, the wetting of the adherend (for example, a polarizing plate) becomes insufficient, and a swelling phenomenon occurs between the adherend and the pressure- . The weight average molecular weight refers to a value obtained by measurement by GPC (gel permeation chromatography).

The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C or lower, more preferably -10 ° C or lower (usually -100 ° C or higher). If the glass transition temperature is higher than 0 占 폚, the polymer tends to flow hardly, for example, the wetting of the polarizing plate becomes insufficient, and tends to cause a swelling occurring between the polarizing plate and the pressure-sensitive adhesive layer of the surface protective film. Especially when the glass transition temperature is lower than -61 캜, a pressure-sensitive adhesive layer having excellent wettability and light fastness to a polarizing plate tends to be obtained. The glass transition temperature of the (meth) acryl-based polymer can be adjusted within the above-mentioned range by suitably changing the monomer components or the composition ratio to be used.

The polymerization method of the (meth) acrylic polymer is not particularly limited, and the polymerization can be carried out by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. In particular, from the viewpoint of workability, In view of the properties such as low staining property on the sieve, solution polymerization is a more preferable form. The resulting polymer may be a random copolymer, a block copolymer, an alternating copolymer or a graft copolymer.

The solution polymerization method is not particularly limited, and for example, there can be mentioned a method of dissolving the above monomer component, polymerization initiator, etc. in a solvent and heating and polymerizing to obtain an acrylic polymer solution containing an acrylic polymer.

As the solvent used in the solution polymerization method, various general solvents can be used. Examples of such a solvent (polymerization solvent) include aromatic hydrocarbons such as toluene, benzene and xylene; Esters such as ethyl acetate and n-butyl acetate; aliphatic hydrocarbons such as n-hexane and n-heptane; Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; And organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. These solvents may be used alone or in combination of two or more.

Examples of the polymerization initiator include, but are not limited to, a peroxide-based polymerization initiator and an azo-based polymerization initiator. The peroxide-based polymerization initiator is not particularly limited, and examples thereof include peroxycarbonate, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide and peroxy ester More specifically, there may be mentioned benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1- ) -3,3,5-trimethylcyclohexane, and 1,1-bis (t-butylperoxy) cyclododecane. Examples of the azo-based polymerization initiator include, but are not limited to, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis Azobis (4-methoxy-2,4-dimethylvaleronitrile), 1, 2-azobis (2-methylpropionyl) Azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4,4-trimethylpentane), 4,4'-azobis-4-cyanovaleric acid, Azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis Azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) hydrochloride, 2,2'-azobis [N- -Carboxyethyl) -2-methylpropionamidine] hydrate, and the like. These polymerization initiators may be used alone or in combination of two or more.

The mixing ratio of the polymerization initiator is not particularly limited, but is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 5 parts by mass, relative to 100 parts by mass of the whole monomer component constituting the (meth) acrylic polymer. 3 parts by mass.

In the solution polymerization method, the heating temperature at the time of polymerization by heating is not particularly limited, but may be, for example, from 50 to 80 캜. The heating time is not particularly limited, but is, for example, 1 to 24 hours.

&Lt; Polyether compound >

The pressure-sensitive adhesive composition preferably contains a polyether compound, and the polyether compound is preferably a surfactant. By mixing the polyether compound at a specific ratio in the above pressure-sensitive adhesive composition, suitable antistatic properties can be imparted, and the wettability of the interlayer filler on the surface of the adherend after the surface protective film is peeled is useful.

Specific examples of the polyether compound include, for example, polyoxyalkylene alkylamine, polyoxyalkylene diamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkylphenyl ether, Nonionic surfactants such as alkylene alkyl ethers, polyoxyalkylene alkylallyl ethers, and polyoxyalkylene alkylphenyl allyl ethers; Anionic surfactants such as polyoxyalkylene alkyl ether sulfuric acid ester salts, polyoxyalkylene alkyl ether phosphoric acid ester salts, polyoxyalkylene alkyl phenyl ether sulfuric acid ester salts and polyoxyalkylene alkyl phenyl ether phosphoric acid ester salts; Other examples include cationic surfactants having a polyoxyalkylene chain (polyalkylene oxide chain), amphoteric surfactants, polyether compounds having polyoxyalkylene chains (including derivatives thereof), polyoxyalkyl (Including derivatives thereof) and the like. These polyether compounds may be used alone or in combination of two or more.

Specific examples of the polyether compound having a polyoxyalkylene chain include a block copolymer of polypropylene glycol (PPG) -polyethylene glycol (PEG), a block copolymer of PPG-PEG-PPG, a block copolymer of PEG-PPG-PEG And the like. Examples of the derivative of the polyether compound having a polyoxyalkylene chain include an oxypropylene group-containing compound (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.) having an ether at the terminal, an oxypropylene group-containing compound (Terminal acetylated PPG and the like), and the like.

Specific examples of the acrylic compound having a polyoxyalkylene chain include a (meth) acrylate polymer having an oxyalkylene group. The oxyalkylene group is preferably 1 to 50, more preferably 2 to 30, from the viewpoint of coordination of the ionic compound in the case where the ionic compound is added as an antistatic component in the addition mole number of the oxyalkylene unit , More preferably 2 to 20 carbon atoms. The terminal of the oxyalkylene chain may be the same as the 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 (meth) acrylic acid alkylene oxide as a monomer unit (component), and specific examples of the (meth) acrylic acid alkylene oxide include Examples of the ethylene glycol group-containing (meth) acrylate include methoxy-polyethylene glycol (meth) acrylates such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) (Meth) acrylate type such as ethoxy-diethylene glycol (meth) acrylate and ethoxy-triethylene glycol (meth) acrylate, butoxy-diethylene glycol Butoxy-polyethylene glycol (meth) acrylate type such as butoxy-triethylene glycol (meth) acrylate, and phenoxy-diethylene glycol (meth) Polyethylene glycol (meth) acrylate such as phenoxy-polyethylene glycol (meth) acrylate such as phenoxy-triethylene glycol (meth) acrylate, 2-ethylhexyl- And methoxy-polypropylene glycol (meth) acrylate type such as methoxy-dipropylene glycol (meth) acrylate.

As the monomer unit (component), other monomer units (components) other than the (meth) acrylic acid alkylene oxide may be used. Specific examples of the other monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s- (Meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (Meth) acrylate, n-decyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl ) Acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms.

Examples of other monomer components other than the (meth) acrylic acid alkylene oxide include a carboxyl group-containing (meth) acrylate, a phosphoric acid group-containing (meth) acrylate, a cyano group-containing (meth) acrylate, a vinyl ester, Containing (meth) acrylate, epoxy group-containing (meth) acrylate, hydroxyl group-containing (meth) acrylate, amide group-containing (meth) It is also possible to suitably use amorpholine, vinyl ethers and the like.

In a more preferred form, the polyether compound is a compound having at least part of (poly) ethylene oxide chain. The blending of the (poly) ethylene oxide chain-containing compound improves the compatibility of the (meth) acryl-based polymer as the base polymer with the antistatic component and appropriately suppresses the bleeding to the adherend, . In particular, when a block copolymer of PPG-PEG-PPG is used, a pressure-sensitive adhesive excellent in low staining property can be obtained. As the polyethylene oxide chain-containing compound, the weight of the (poly) ethylene oxide chain in the total polyether compound is preferably 5 to 90% by mass, more preferably 5 to 85% by mass, 5 to 80 mass%, and most preferably 5 to 75 mass%.

Specific examples of the polyether compound as a surfactant include anionic type reactive surfactant having a (meth) acryloyl group or an allyl group, a nonionic type reactive surfactant, a cationic type reactive surfactant, and the like .

Examples of the anionic type reactive surfactant include those represented by the formulas (A1) to (A10).

Wherein R ₁ in the formula (A1) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, X represents an anionic hydrophilic group, R ₃ and R ₄ are the same or different, An alkylene group having 1 to 6 carbon atoms, and an average addition mole number m and n is 0 to 40, provided that (m + n) is a number of 3 to 40).

R ₂ in the formula (A2) represents hydrogen or a methyl group, R ₂ and R ₇ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, R ₃ and R ₅ are the same or different, a represents, R ₄ and R ₆ are the same or different, hydrogen, an alkyl group, a benzyl group or represents a group of styrene, X represents an anionic hydrophilic group, an average addition mole number m and n is from 0 to 40, provided that (m + n) Represents a number from 3 to 40].

Wherein R ₁ in the formula (A3) represents hydrogen or a methyl group, R ₂ represents an alkylene group having 1 to 6 carbon atoms, X represents an anionic hydrophilic group, and an average addition mole number n is 3 to 40.

Wherein R ₁ in the formula (A4) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, R ₃ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms , And X represents an anionic hydrophilic group, and the average addition moles m and n are 0 to 40, provided that m + n is 3 to 40.

R ₂ in the formula (A5) represents a hydrocarbon group, an amino group or a carboxylic acid residue, R ₂ represents an alkylene group having 1 to 6 carbon atoms, X represents an anionic hydrophilic group, and an average addition molar number n is 3 to 40 Lt; / RTI &gt;

Equation (A6) of R ₁ is a hydrocarbon group, R ₂ having 1 to 30 carbon atoms is a hydrocarbon group of hydrogen or a group having 1 to 30 carbon atoms, R ³ represents hydrogen or a propenyl group, R ₄ is alkyl of 1 to 6 carbon atoms X represents an anionic hydrophilic group, and the average addition mole number n represents a number of from 3 to 40].

Wherein R ₁ in the formula (A7) represents hydrogen or a methyl group, R ₂ and R ₄ are the same or different and each is an alkylene group having 1 to 6 carbon atoms, R ₃ is a hydrocarbon group having 1 to 30 carbon atoms, M is An average addition mol number m and n is 0 to 40, provided that (m + n) is a number of 3 to 40).

Equation (A8) of the R ₁ and R ₅ are the same or different, represents a hydrogen or a methyl group, R ₂ and R ₄ are the same or different and each represents an alkylene group having 1 to 6, R ₃ is C 1 -C (M + n) represents a number of 3 to 40, and M represents hydrogen, an alkali metal, an ammonium group or an alkanolammonium group, and the average addition moles m and n are 0 to 40,

Wherein R ₁ represents an alkylene group having 1 to 6 carbon atoms, R ₂ represents a hydrocarbon group having 1 to 30 carbon atoms, M represents hydrogen, an alkali metal, an ammonium group or an alkanolammonium group, Represents a number of 3 to 40]

[Wherein R ₁ , R ₂ and R ₃ in the formula (A10) are the same or different and each represents hydrogen or a methyl group, and R ₄ is a hydrocarbon group having 0 to 30 carbon atoms (when the number of carbon atoms is 0, R ₄ is absent) And m and n are 0 to 40, with the proviso that (m + n) is an integer of 3 or more, and R ₅ and R ₆ are the same or different and each represents an alkylene group of 1 to 6 carbon atoms, X represents an anionic hydrophilic group, Lt; / RTI &gt; to 40;

X in the formulas (A1) to (A6) and (A10) represents an anionic hydrophilic group. Examples of the anionic hydrophilic group include those represented by the following formulas (a1) to (a2).

[M ₁ in the formula (a1) represents hydrogen, an alkali metal, an ammonium group or an alkanolammonium group]

[M ₂ and M ₃ in the formula (a2) are the same or different and each represents hydrogen, an alkali metal, an ammonium group or an alkanolammonium group]

Examples of the nonionic type reactive surfactant include those represented by the formulas (N1) to (N6).

Wherein R ₁ in the formula (N1) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, R ₃ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms , The average addition mole number m and n is 0 to 40, provided that (m + n) is a number from 3 to 40)

R ₁ in the formula (N2) represents hydrogen or a methyl group, R ₂ , R ₃ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, 40, and (n + m + 1) is 3 to 40)

R ₁ in the formula (N3) represents hydrogen or a methyl group, R ₂ and R ₃ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, R ₄ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms , The average addition mole number m and n is 0 to 40, provided that (m + n) is a number from 3 to 40)

Wherein R ₁ and R ₂ in the formula (N4) are the same or different and each represents a hydrocarbon group of 1 to 30 carbon atoms, R ₃ represents hydrogen or a propenyl group, R ₄ represents an alkylene group having 1 to 6 carbon atoms, The addition mole number n represents a number of 3 to 40]

R ₁ and R ₃ in the formula (N5) are the same or different and each represents an alkylene group having 1 to 6 carbon atoms; R ₂ and R ₄ are the same or different and each is hydrogen, a hydrocarbon group having 1 to 30 carbon atoms or an acyl group And the average addition molar number m and n is 0 to 40, provided that (m + n) is a number of 3 to 40)

Equation (N6) of the R _1, R ₂ and R ₃ are the same or different, represents a hydrogen or a methyl group, R ₄ is a hydrocarbon group having a carbon number of 0 to 30 (in the case of a carbon number of 0, indicating that there is no R ₄₎ R ₅ and R ₆ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms and the average addition molar number m and n is 0 to 40 and the sum of m and n is 3 to 40;

The number-average molecular weight (Mn) of the polyether compound is suitably 50000 or less, preferably 200 to 30000, more preferably 200 to 10000, and usually 200 to 5000. When Mn is larger than 50000, compatibility with the (meth) acrylic polymer as the base polymer is lowered, and the pressure-sensitive adhesive layer tends to whiten. If Mn is less than 200, contamination by the polyether compound may easily occur. Here, Mn means the value in terms of polystyrene obtained by gel permeation chromatography (GPC).

Specific examples of commercially available products of the above polyether compounds include adekafluronic 17R-4, adecafluronic 25R-1, adecafluronic 25R-2, adecafluronic L- (All available from ADEKA), Emulsion 120, Latex PD-420 and Latex PD-430 (all manufactured by All Gao Corporation), Adekariassof ER-10 and Adekariassof NE- 40, Surfynol 420, Surfynol 485 (all manufactured by Nissin Chemical Industries, Ltd.), Aquaron HS-10: Hytenol N-08, 10, Aquaron RN-20, Hytenol NF-08, Flysurf A212C (all manufactured by Dai-ichi Kogyo Seiyaku), PEG400, PEG600, Newpol PE-34 and Sannix PP200 , Blemmer PME-400, Blemmer PME-1000, and Blemmer 50POEP-800B (all of which are similar to those of Nissi).

The blending amount of the polyether compound is 0.03 to 14 parts by mass, preferably 0.04 to 13 parts by mass, more preferably 0.05 to 12 parts by mass, and most preferably 100 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer Is 0.05 to 10 parts by mass. If the blending amount is too small, appropriate antistatic properties (antistatic effect) can not be obtained, and wettability to the interlayer filler on the surface of the adherend after the surface protective film is peeled can not be ensured. If too much, contamination with the polyether compound tends to occur, which is not preferable.

&Lt; Antistatic component >

In the surface protective film of the present invention, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer may contain an antistatic component, and the antistatic component may contain an ionic compound. Examples of the ionic compound include alkali metal salts and / or ionic liquids. By containing these ionic compounds, excellent antistatic properties can be imparted. In addition, the pressure-sensitive adhesive layer (using the antistatic component) formed by crosslinking the pressure-sensitive adhesive composition containing the antistatic component as described above is antistatic to an adherend (for example, a polarizing plate) , A surface protective film with reduced contamination to an adherend is obtained. As a result, it becomes very useful as an antistatic surface protective film in a technical field related to optical and electronic parts, in which electrification and contamination are particularly serious problems.

<Cross-linking agent>

In the surface protective film of the present invention, it is preferable that the pressure-sensitive adhesive composition contains a crosslinking agent. In the present invention, the pressure-sensitive adhesive composition may be used to form a pressure-sensitive adhesive layer. For example, a surface protective film (pressure-sensitive adhesive layer) having superior heat resistance can be obtained by appropriately adjusting the crosslinking degree of the constituent unit, the constituent ratio, the cross-linking agent, and the like of the (meth) acrylic polymer.

As the crosslinking agent to be used in the present invention, an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative and a metal chelate compound may be used, and in particular, the use of an isocyanate compound is a preferable form. These compounds may be used alone or in combination of two or more.

Examples of the isocyanate compound include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI) and dimeric acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, Alicyclic isocyanates such as isophorone diisocyanate (IPDI), aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene isocyanate (XDI), isocyanate compounds A polyisocyanate-modified product modified by an allophanate bond, a biuret bond, an isocyanurate bond, a uretdione bond, a urea bond, a carbodiimide bond, a uretonimine bond, an oxadiazinetrione bond or the like . For example, as commercial products, trade names: Takenate 300S, Takenate 500, Takenate D165N, Takenate D178N (manufactured by Takeda Yakuhin Kogyo Co., Ltd.), Sumidur T80, Sumidur L, Desmodur N3400 (manufactured by Sumika Bayer Urethane Co., Ltd.), Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.). These isocyanate compounds may be used alone, or two or more isocyanate compounds may be used in combination, or 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 a cohesive property and an anti-repulsion property (adhesiveness to a curved surface), and a surface protective film excellent in adhesion reliability can be obtained.

Examples of the epoxy compound include N, N, N ', N'-tetraglycidyl-m-xylenediamine (trade name TETRAD-X, manufactured by Mitsubishi Gas Chemical Company) Diglycidylaminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company).

Examples of the melamine resin include hexamethylol melamine and the like. Examples of the aziridine derivative include commercial products such as HDU, TAZM, and TAZO (available from Sogo Kogyo Co., Ltd.).

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

The content of the crosslinking agent to be used in the present invention is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 8 parts by mass, and most preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of the (meth) By mass to 6% by mass, and most preferably from 1 to 5% by mass. When the content is less than 0.01 part by mass, crosslinking by the crosslinking agent becomes insufficient, and the cohesive force of the obtained pressure-sensitive adhesive layer becomes small, so that sufficient heat resistance tends not to be obtained, and tends to cause adhesive residue. On the other hand, when the content is more than 10 parts by mass, the cohesive force of the polymer is large, the fluidity is decreased, the wettability to the adherend (for example, the polarizing plate) becomes insufficient and the adhesion between the adherend and the pressure- Which is the cause of swelling. In addition, if the amount of the crosslinking agent is large, the peeling charging property tends to be lowered.

&Lt; Crosslinking catalyst &

The pressure-sensitive adhesive composition may further contain a crosslinking catalyst for more effectively proceeding any one of the above-mentioned crosslinking reactions. Examples of such a crosslinking catalyst include tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonato) iron, tris (hexane-2,4-dione) Tris (heptane-2,4-dionate) iron, tris (heptane-3,5-dionate) iron, tris (5-methylhexane- (2,6-dimethylheptane-3,5-dionate) iron, tris (nonane-2,4-dioneato) iron, tris Iron, tris (nonane-4,6-dionate) iron, tris (2,2,6,6-tetramethylheptane-3,5-dionate) iron, tris (tridecane-6,8- Iron, tris (1-phenylbutane-1,3-dione) iron, tris (hexafluoroacetylacetonato) iron, tris (acetoacetic acid ethyl) (Acetoacetic acid isopropyl) iron, tris (acetoacetic acid-n-butyl) , Tris (acetoacetic acid-sec-butyl) iron, tris (acetoacetic acid-tert-butyl) iron, tris (propionylacetic acid methyl) ) Iron, tris (propionylacetic acid isopropyl) iron, tris (propionylacetate-n-butyl) iron, tris (propionylacetate- Based catalysts such as iron (benzoyl acetoacetate), tris (dimethyl malonate), tris (diethyl malonate), trimethoxy iron, triethoxy iron, triisopropoxy iron and ferric chloride . These crosslinking catalysts may be used alone or in combination of two or more.

The content (amount of use) of the crosslinking catalyst is not particularly limited, but is preferably 0.0001 to 1 part by mass, more preferably 0.001 to 0.5 part by mass with respect to 100 parts by mass of the (meth) acrylic polymer. Within the above range, the speed of the crosslinking reaction is increased when the pressure-sensitive adhesive layer is formed, which is a preferable form.

<Crosslinking retardant>

The pressure-sensitive adhesive composition may also contain a crosslinking retarder. The crosslinking retarder is not particularly limited and includes, for example, β-keto esters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate and stearyl acetoacetate, , 2,4-hexanedione, and benzoyl acetone. Among them, acetylacetone can be used. The crosslinking retarders may be used alone or in combination of two or more.

The content (amount of use) of the crosslinking retarder is not particularly limited, but is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the solvent. Within this range, the usable time of the pressure-sensitive adhesive can be extended, which is a preferable form.

The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer of the present invention may further contain a solvent. As the solvent, for example, there can be mentioned a solvent used in the solution polymerization method described above. The solvent in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer of the present invention may be the same as or different from the solvent used in the solution polymerization method. The solvent in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer of the present invention may be used alone or in combination of two or more.

The pressure-sensitive adhesive composition may contain other known additives, for example, a coloring agent, a powder such as a pigment, a surfactant, a plasticizer, a tackifier, a low molecular weight polymer, a surface lubricant, a leveling agent, It may be suitably added in accordance with the use of a corrosion inhibitor, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, a silane coupling agent, an inorganic or organic filler, a metal powder, a particulate or thin film.

&Lt; Adhesive layer and surface protective film &

The surface protective film for a touch panel of the present invention is obtained by forming the pressure sensitive adhesive layer on the second surface of the substrate using a pressure sensitive adhesive composition. The pressure sensitive adhesive composition is generally crosslinked after the pressure sensitive adhesive composition is applied. However, It is also possible to transfer the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition to a substrate or the like.

A method of forming a pressure-sensitive adhesive layer on a substrate is not particularly limited. For example, the pressure-sensitive adhesive composition (solution) is applied to a substrate and the pressure-sensitive adhesive layer is formed on the substrate by drying and removing the polymerization solvent. Thereafter, curing may be carried out for the purpose of adjusting the component migration of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. When the pressure-sensitive adhesive composition is coated on a substrate to produce a surface protective film, at least one solvent other than the polymerization solvent may be newly added to the pressure-sensitive adhesive composition so as to be uniformly applied on the substrate.

As a method of forming the pressure-sensitive adhesive layer in the production of the surface protective film of the present invention, a known method used in the production of pressure-sensitive adhesive tapes is used. Specific examples include extrusion coating methods such as roll coating, gravure coating, reverse coating, roll brush, spray coating, air knife coating, die coater and the like.

The surface protective film of the present invention is usually produced so that the thickness of the pressure sensitive adhesive layer is 3 to 100 탆, preferably 5 to 50 탆. When the thickness of the pressure-sensitive adhesive layer is within the above-mentioned range, it is preferable that a proper balance of re-peeling property and adhesiveness can be easily obtained.

The total thickness of the surface protective film of the present invention is preferably 1 to 400 占 퐉, more preferably 10 to 200 占 퐉, and still more preferably 20 to 100 占 퐉. Within the above range, the adhesive property (re-releasability, adhesiveness, etc.), workability, and appearance are excellent, which is a preferable form. The total thickness means a total thickness including all layers such as a substrate, a pressure-sensitive adhesive layer, and an antistatic layer.

<Separator>

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

As the material constituting the separator, there are a paper or a plastic film, but a plastic film is suitably used because of its excellent surface smoothness. The film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, and examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, A copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the separator is usually 5 to 200 mu m, preferably 10 to 100 mu m or so. Within this range, it is preferable that the bonding workability to the pressure-sensitive adhesive layer and the peeling workability from the pressure-sensitive adhesive layer are excellent. If necessary, the separator may be subjected to antistatic treatment such as release, antifouling, coating, kneading, and vapor deposition using a silicone, fluorine, long chain alkyl or fatty acid amide releasing agent or silica powder.

&Lt; Optical member &

The optical member mounted on the touch panel of the present invention is preferably protected by the surface protection film for the touch panel. Since the surface protective film has excellent antistatic property and stability with time of peeling electrification voltage and can confirm the operation of the touch panel and also has excellent wettability with respect to the interlayer filler on the surface of the adherend after peeling off the surface protective film, (Surface protective film) such as at the time of transportation, shipment inspection and the like, and is useful for protecting the surface of the optical member (such as a polarizing plate mounted on the touch panel). In particular, it is very useful for antistatic use in technical fields relating to optical and electronic parts, in which electrification is a particularly serious problem, because it can be used in plastic products which are likely to generate static electricity.

Example

Hereinafter, some embodiments related to the present invention will be described, but the present invention is not intended to be limited to what is shown in these embodiments. In the following description, &quot; part &quot; and &quot;% &quot; are based on mass unless otherwise specified. In the table, the compounding amount (addition amount) showed a solid content or a solid content ratio.

Each characteristic in the following description was measured or evaluated as follows.

&Lt; 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 mass% (THF solution)

Sample injection volume: 10 μl

Eluent: THF

Flow rate: 0.6 ml / min

Measuring temperature: 40 ° C

column:

Sample column; TSKguardcolumn SuperHZ-H (1) + TSK gel SuperHZM-H (2)

Reference column; TSK gel SuperH-RC (1)

Detector: Differential refractometer (RI)

In addition, the weight average molecular weight was determined in terms of polystyrene conversion.

&Lt; Glass transition temperature (Tg) >

The glass transition temperature Tg (占 폚) was determined by the following formula using the following literatures as the glass transition temperature Tgn (占 폚) of the homopolymer by each monomer.

Wherein Tg (° C) is the glass transition temperature of the copolymer, Wn (-) is the weight fraction of each monomer, and Tgn (° C.) is the glass transition temperature of the copolymer. ) Is the glass transition temperature of the homopolymer by each monomer, and n is the kind of each monomer. Literature:

2-ethylhexyl acrylate (2EHA): -70 占 폚

2-hydroxyethyl acrylate (HEA): -15 ° C

4-hydroxybutyl acrylate (4HBA): -32 &lt; 0 &gt; C

Acrylic acid (AA): 106 DEG C

As a literature value, reference was made to "Polymer Handbook" (John Wiley & Sons), "Synthesis and Design of Acrylic Resin and Development of New Applications" (published by Central Management Development Center Press).

&Lt; Measurement of Surface Resistance Value >

Measurement was carried out in accordance with JIS-K-6911 using a resistivity meter (Mitsubishi Chemical's Analizer, Hirestor UP MCP-HT450 type) at an ambient temperature of 23 캜 and a humidity of 50% RH.

The surface resistance value (Ω / □) of the present invention is preferably 1.0 × 10 ⁷ or more and 1.0 × 10 ⁷ or less, more preferably 1.0 × 10 ⁷ or more, ^Is less than ¹¹ , more preferably not less than 1.0 x 10 ⁸ and less than 5.0 x 10 ¹⁰ , and still more preferably not less than 1.0 x 10 ⁹ and less than 2.0 x 10 ¹⁰ . The surface protective film showing the surface resistance value within the above range can be suitably used as a surface protective film to be used in, for example, processing or transporting an article disliking static electricity such as a liquid crystal cell or a semiconductor device. The surface protective film exhibiting the surface resistance value within the above range can be confirmed to be operable even when the polarizing plate is mounted above the touch panel sensor and the surface protective film is attached on the polarizing plate.

<Check operation of touch panel>

The operation confirmation evaluation of the touch panel was performed using the iPhone 5s (manufactured by Apple) equipped with the in-cell type touch panel. First, a surface protective film was attached on the screen of the iPhone 5s. When the screen was fingered with a finger, the touch panel was observed to observe the reaction.

○: When the touch panel responds correctly.

X: The touch panel does not respond correctly.

<Water contact angle>

After adhering the surface protective film to the surface of the adherend (hard coating film) at a temperature of 23 DEG C and a humidity of 50%, the film was placed in an autoclave and treated at a temperature of 50 DEG C and a pressure of 5 atm for 15 minutes, 23 DEG C and 50% RH for 12 hours. A surface protective film was adhered to the surface of the adherend to which the surface protective film was adhered under the atmosphere of a temperature of 23 占 폚 and a humidity of 50% RH by a droplet method using a water contact angle measuring apparatus (trade name "DM700", manufactured by Kyowa Chemical Co., 2.8 [mu] L of water drop was dropped, and the angle formed by the tangent line between the adherend surface and the droplet drop end after 1 second after dropping was measured to obtain the &quot; water contact angle (DEG) &quot;. (Wettability) was evaluated as &quot; good (good) &quot; when the water contact angle was 35 DEG or less, and &quot; poor (wettability)

The contact angle of the adherend which had not been subjected to any treatment was 37.2 °. That is, the adherend used in this evaluation is a triacetylcellulose film having a water contact angle of 37.2 DEG.

&Lt; Wettability of interlayer filler >

The surface protective film was adhered to the surface of the adherend at a temperature of 23 캜 and a humidity of 50% and then charged in an autoclave and treated at a temperature of 50 캜, a pressure of 5 atm for 15 minutes, % For 12 hours. Thereafter, the adherend to which the surface protective film was adhered was cut to a length of 40 mm and a width of 40 mm and attached to a glass plate having a length of 50 mm and a width of 50 mm. The glass plate was placed in a spin coater (trade name: K- ). Subsequently, the surface protective film was peeled from the adherend, and 4 ml of the trade name &quot; SVR7000 series &quot; (Dexerials) was applied as an interlayer filler to the surface of the adherend to which the surface protective film was adhered. And the interlayer filler was spread uniformly. After standing at a temperature of 23 占 폚 and a humidity of 50% for 1 hour, the distance over which the interlayer filler was repelled from the rim of the adherend was regularly measured.

Further, the same measurement was carried out using the trade name &quot; WORLD ROCK HRJ-21 &quot; (manufactured by Kyoritsu Tsugaku 3) as an intercalation filler.

When the interlayer filler of "SVR7000 series" and "WORLD ROCK HRJ-21" is used, the case where the distance of repulsion from the rim is shorter than 2 mm is referred to as "good" The case where the distance of repulsion from the rim was 2 mm or more was evaluated as &quot; bad (X) &quot;. The adherend used in the evaluation is the same as the adherend used in the evaluation of the &quot; water contact angle &quot;.

&Lt; Measurement of Polarizer Peeling Voltage (Polarizer Side) >

The surface protective film 1 of each example was cut to a size of 70 mm in width and 130 mm in length and the release liner was peeled off. Thereafter, as shown in Fig. 3, the acrylic plate 10 (manufactured by Mitsubishi Rayon Co., A surface protective film (1) was laminated on the surface of a polarizing plate 20 (SEG1423DU polarizer, width: 70 mm, length: 100 mm) bonded to a polarizer 20 (Nitto Denko Corporation polarizer, Was released from the end of the polarizing plate 20 by 30 mm, and was pressed with a hand roller.

The sample was allowed to stand for one day under an environment of 23 ° C × 50% RH, and then set at a predetermined position on a sample fixing table 30 having a height of 20 mm. The end portion of the surface protective film 1 which was 30 mm away from the polarizing plate 20 was fixed to an automatic winder (not shown), and peeled off at a peeling angle of 150 ° and a peeling rate of 10 m / min. The potential measuring device 40 (type "KSD-0103" manufactured by Kasuga Electric Co., Ltd.) in which the potential of the adherend (polarizing plate) generated at this time was fixed at a position 100 mm in height from the center of the polarizing plate 20, Initial polarizing plate peeling electrification voltage &quot; was measured. The measurement was carried out in an environment of 23 캜 and 50% RH.

After leaving for one week (seven days) under the environment of 23 ° C × 50% RH, "polarization plate peeling electrification voltage with time" was measured in the same manner as in "initial polarizer peeling electrification voltage". The measurement was carried out in an environment of 23 캜 x 50% RH.

The polarizing plate peeling voltage is a peeling electromotive voltage derived from the antistatic layer and the pressure-sensitive adhesive layer constituting the surface protective film of the present invention, and contributes to the antistatic property.

In the present invention, the polarizing plate peeling electrification voltage (kV) (both the initial value and the initial value) is preferably 1.8 kV or less, more preferably 1.7 kV or less, and further preferably 1.6 kV or less. Within the above range, for example, damage to the liquid crystal driver or the like can be prevented, which is a preferable form.

<Contamination of Polarizer>

The surface protective film was cut into pieces each having a width of 50 mm and a length of 80 mm for each of the release liner, and the release liner was removed to expose the adhesive surface. The pressure-sensitive adhesive surface was pressed with a hand roller to a polarizing plate (SEG1423DU polarizing plate, manufactured by Nitto Denko Corporation). This was allowed to stand for one week under an environment of 23 캜 x 50% RH, and then the surface protective film was peeled off from the adherend by hand. The surface of the adherend after peeling was observed with naked eyes under a dark spot (a normal indoor environment with a ceiling fluorescent lamp illuminated) and under a dark room fluorescent lamp (an environment in which only a desk fluorescent lamp was lit with a shielding curtain to block external light) The state was evaluated. The evaluation criteria are as follows.

○: When the contamination is not visible under the spot.

X: The contamination was observed under the spot.

<Preparation of acrylic polymer (A) for pressure-sensitive adhesive layer>

100 parts by mass of 2-ethylhexyl acrylate (2EHA), 4 parts by mass of 2-hydroxyethyl acrylate (HEA), and 2 parts by mass of a polymerization initiator were added to a four-necked flask equipped with a stirrer, a thermometer, , 0.2 parts by mass of 2'-azobisisobutylonitrile and 157 parts by mass of ethyl acetate were introduced into the flask, and nitrogen gas was introduced while stirring slowly. The polymerization reaction was carried out for 6 hours while maintaining the liquid temperature in the flask at around 65 ° C, (A) solution (40 mass%) was prepared. The acrylic polymer (A) had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of -68 ° C.

<Preparation of acrylic polymer (B) for pressure-sensitive adhesive layer>

100 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of 4-hydroxybutyl acrylate (4HBA), and 10 parts by mass of acrylic acid (AA) were added to a four- necked flask equipped with a stirrer, a thermometer, 0.2 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 157 parts by mass of ethyl acetate were charged, nitrogen gas was introduced with gentle stirring, and the liquid temperature in the flask was maintained at around 65 ° C to obtain 6 Hour polymerization reaction was carried out to prepare an acrylic polymer (B) solution (40 mass%). The acrylic polymer (B) had a weight average molecular weight of 540,000 and a glass transition temperature (Tg) of -67 ° C.

&Lt; Preparation of aqueous solution for antistatic layer (C)

(Aquapass, weight average molecular weight: 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, hexamethylene (25% aqueous solution) blocked with diisopropylamine as a crosslinking agent, 100 parts by mass of a solid content of a binder, 75 parts by mass of a conductive polymer as a solid fraction, and 100 parts by mass of a solid content of a crosslinking agent as a lubricant were added to a mixed solvent of water / ethanol (1/3) And 30 parts by mass of the lubricant as a solid fraction were added, and the mixture was stirred for about 20 minutes and sufficiently mixed. Thus, an aqueous solution for antistatic layer (C) of about 0.4% NV was prepared.

&Lt; Preparation of aqueous solution for antistatic layer (D) >

0.5% of poly (3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonate (weight average molecular weight of 150,000) as a conductive polymer were used as a binder resin, Bayern MD-1480 (25% aqueous solution, (Bytron P, manufactured by HCStark Co., Ltd.) containing 0.8% PSS in a mixed solvent of water / ethanol (1/1), 100 parts by mass of a solid content of the binder, and 50 parts by mass of a solid content of a conductive polymer And 2.5 parts by mass of a melamine-based cross-linking agent, and the mixture was stirred for about 20 minutes and sufficiently mixed. Thus, an aqueous solution for antistatic layer (D) of about 0.4% NV was prepared.

&Lt; Preparation of antistatic layer-attached base material &

(C) or (2) on a corona-treated surface of a transparent polyethylene terephthalate (PET) film (polyester film) having a thickness of 38 m, a width of 30 cm and a length of 40 cm, D) was applied so as to have a thickness of 30 nm or 50 nm after drying. The coating material was heated at 130 占 폚 for 1 minute and dried to prepare an antistatic layer-attached substrate having an antistatic layer on the first surface of the PET film.

&Lt; Example 1 >

[Preparation of acrylic pressure-sensitive adhesive solution]

The acrylic polymer (A) solution (40% by mass) was diluted with ethyl acetate to 20% by mass, and 500 parts by mass (solid content: 100% by mass) of the acrylic polymer (A) was added with an isocyanurate of hexamethylene diisocyanate 3 parts by mass (solids content: 3 parts by mass), 3 parts by mass of dibutyl tin dilaurate (trade name: OL-1, manufactured by Tokyo Fine Chemical) (1% by mass ethyl acetate solution) , 3 parts by mass of acetylacetone as a crosslinking retarder (when converted to 100 parts by mass of a solvent), and 3 parts by mass of polyethylene glycol (trade name: PEG400, number average molecular weight: 400, ) Were added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution.

[Production of surface protective film]

The acrylic pressure-sensitive adhesive solution was coated on the opposite side of the antistatic layer of the base material (base with antistatic layer) having the antistatic layer and heated at 130 占 폚 for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 15 占 퐉. Subsequently, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 탆) as a separator with a silicone treatment on one side was bonded to the surface of the pressure-sensitive adhesive layer to prepare a surface protective film for a touch panel.

&Lt; Examples 2 to 10 and Comparative Examples 1 to 4 >

A surface protective film was prepared in the same manner as in Example 1, based on the blending contents in Tables 1 to 3.

The surface protective films according to Examples and Comparative Examples were subjected to the various measurements and evaluations described above, and the results are shown in Tables 4 and 5.

The abbreviations in Tables 1 and 3 are described below.

2EHA: 2-ethylhexyl acrylate

HEA: 2-hydroxyethyl acrylate

4HBA: 4-hydroxybutyl acrylate

AA: Acrylic acid (AA)

Adekafluronic 25R-1: polyoxyethylene-polyoxypropylene block copolymer (polyether compound, manufactured by ADEKA)

Surfynol 420: Polyether compound of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (polyether compound, manufactured by Nissin Chemical Industry Co., Ltd.)

Surfynol 485: Polyether compound of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (Nippon Kayaku, polyether compound)

Aquaron HS-10: Polyoxyethylene nonyl propenyl phenyl ether ammonium sulfate (polyether compound, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)

Latex PD-420: polyoxyalkylene alkenyl ether (manufactured by Kao Corporation, polyether compound)

PEG400: polyethylene glycol (number average molecular weight: 400, Sanyo Chemical Industries, polyether compound)

PP200: polypropylene glycol (number-average molecular weight: 200, polyether compound, manufactured by SANYO Chemical Industry Co., Ltd.)

From the above evaluation results, it was confirmed that the antistatic property and the elongation stability of the peeling electrification were excellent in all the examples, and that there was no problem in confirming the operation of the touch panel, and it was practical. Further, it was confirmed that when the pressure-sensitive adhesive layer was blended with the polyether compound at a specific ratio, it was also excellent in wettability and contamination.

On the other hand, in Comparative Example 1, since no polyether compound was used, it was confirmed that the wettability was poor and the antistatic property was also poor. Further, in Comparative Example 2, it was confirmed that the antistatic property could not be obtained because the amount of the polyether compound was less than a desired ratio. In Comparative Example 3, since a large amount of polyether compound was blended, it was confirmed that the stainability was poor. In Comparative Example 4, a water dispersion type conductive polymer (PEDOT / PSS) was used as a component constituting the antistatic layer, and the surface resistance value was too low, so that the operation of the touch panel could not be confirmed. . Further, it was confirmed that the antistatic property and the deterioration with time of the peeling electrification voltage were poor. Although the details of the reason why such a problem occurs are not clear, it is presumed that deterioration of antistatic property occurred as a whole of the surface protective film based on deterioration of the antistatic layer.

The surface protective film disclosed herein can be used for manufacturing optical members such as a polarizing plate used as a component of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescence (EL) display, etc., It is suitable as a surface protective film for protection. In particular, it is useful as a surface protective film (surface protective film for optical use) applied to an optical member such as a polarizing plate mounted on a touch panel of an on-cell type or an incell type.

1: Surface protective film
3: Touch panel
10: Acrylic plate
20: polarizer
30: Sample Stands
40: Potentiometer
11: Antistatic layer
12: substrate
13: Pressure-sensitive adhesive layer
31: polarizer
32: Touch sensor
33: base glass
34: liquid crystal

Claims (6)

A surface protective film for a touch panel, comprising: a substrate having a first side and a second side; an antistatic layer formed on the first side of the substrate; and a pressure-sensitive adhesive layer formed on the second side of the substrate with a pressure- ,
Wherein the antistatic layer is formed of an antistatic agent composition containing a polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate crosslinking agent as a crosslinking agent,
Wherein the pressure-sensitive adhesive composition contains a (meth) acrylic polymer and a polyether compound,
Wherein the polyether compound is contained in an amount of 0.03 to 14 parts by mass based on 100 parts by mass of the (meth) acryl-based polymer. The method according to claim 1,
A surface protective film for a touch panel, wherein the substrate contains polyethylene terephthalate and / or polyethylene naphthalate. The method according to claim 1,
Wherein the antistatic agent composition further comprises a fatty acid amide as a lubricant. The method according to claim 1,
Wherein the polyether compound is a surfactant. An optical member mounted on a touch panel, wherein the optical member is protected by the surface protection film for a touch panel according to any one of claims 1 to 4. A method of manufacturing a surface protective film for a touch panel according to any one of claims 1 to 4,
A step of preparing an aqueous solution containing the antistatic agent composition,
Applying the aqueous solution to the first surface of the base material and drying the base material to prepare an antistatic layer.

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