Surface protective film, and use of the same

Abstract

To provide a surface protective film having a substrate layer, an adhesive layer, and a release liner in this order that can prevent mistake before releasing the release liner, can prevent the failure in peeling off the release liner when using, and is excellent in optical inspection property, and an optical device and an electronic device including such a surface protective film.SOLUTION: A surface protective film includes a substrate layer, an adhesive layer, and a release liner in this order, where a b* value of the whole surface active film is 0.70 or more, a transmittance of light having 550 nm wavelength of the whole surface protective film is 85% or more, and a b* value of a laminate excluding the release liner from the surface protective film is less than 0.50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a surface protection film, and also to an optical device and an electronic device including such a surface protection film. [Background technology]

[0002] BACKGROUND ART Surface protective films are provided on the surfaces of optical devices such as displays and imaging devices, electronic devices, and optical members such as films and glass materials that are components of these devices, for the purposes of surface protection, imparting impact resistance, etc.

[0003] Typical examples of surface protection films include those that are temporarily attached to the device during assembly, processing, transportation, etc., before use, and are then peeled off before use (those used as processing materials), and those that remain attached to the device surface even when the device is in use (those intended for permanent adhesion) (see, for example, Patent Document 1).

[0004] A surface protection film typically comprises a pressure-sensitive adhesive layer on the main surface of a film substrate, and a release liner is usually provided on the surface of the pressure-sensitive adhesive layer. When using the surface protection film, the release liner is peeled off, and the film is then attached to the surface of an adherend to be protected via the exposed pressure-sensitive adhesive layer (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3518677 [Patent Document 2] Patent No. 6249617 Summary of the Invention [Problem to be solved by the invention]

[0006] Surface protection films before use (before the release liner is peeled off) are usually stored in similar roll or laminate form. For example, when different types of surface protection films are lined up, it can be difficult to visually distinguish them from one another, which can lead to mix-ups.

[0007] Furthermore, it is difficult to visually distinguish the appearance of the surface protection film before and after the release liner has been removed, which poses the problem of forgetting to remove the release liner when using the surface protection film.

[0008] Furthermore, since surface protection films can be used for purposes such as surface protection and impact resistance of optical devices, they are required to be free of foreign matter, etc. Therefore, they are required to pass precise optical inspections and have good optical inspectability.

[0009] An object of the present invention is to provide a surface protection film having a base layer, a pressure-sensitive adhesive layer, and a release liner in this order, which can prevent mix-ups before the release liner is peeled off, can prevent forgetting to peel off the release liner during use, and has excellent optical inspectability, and also to provide an optical device and an electronic device including such a surface protection film. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have found that the problems of the present invention can be solved by appropriately adjusting the color tone and transmittance of the entire surface protection film and the laminate obtained by removing the release liner from the surface protection film. In particular, the color tone of L * a * b * b, which is particularly related to yellowness among color systems * It has been found that the object of the present invention can be achieved by adjusting the value to an appropriate range and adjusting the transmittance to an appropriate range.

[0011] [1] The surface protection film according to an embodiment of the present invention is a surface protection film having a base layer, a pressure-sensitive adhesive layer, and a release liner in this order, and b of the entire surface protection film * the surface protective film as a whole has a transmittance of 85% or more for light having a wavelength of 550 nm, and the surface protective film as a laminate excluding the release liner has a b * The value is less than 0.50. [2] In the surface protection film according to the above [1], b of a laminate in which 15 sheets of the surface protection film are laminated * The value may be 7.00 or greater. [3] In the surface protective film according to the above [1] or [2], a laminate formed by laminating 15 of the surface protective films may have a reflectance of less than 40.0%. [4] In the surface protective film according to any one of the above items [1] to [3], the thickness of the surface protective film may be 10 μm to 500 μm. [5] In the surface protective film according to any one of the above items [1] to [4], the release liner may have a thickness of 1 μm to 300 μm. [6] An optical device according to an embodiment of the present invention includes the surface protection film according to any one of [1] to [5] above. [7] An electronic device according to an embodiment of the present invention includes the surface protection film according to any one of [1] to [5] above. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a surface protection film having a base layer, a pressure-sensitive adhesive layer, and a release liner in this order, which can prevent mix-ups before the release liner is peeled off, can prevent forgetting to peel off the release liner during use, and has excellent optical inspectability. It is also possible to provide an optical device and an electronic device including such a surface protection film. [Brief explanation of the drawings]

[0013] [Figure 1]1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] In this specification, the term "(meth)acrylic" means "acrylic and / or methacrylic," the term "(meth)acrylate" means "acrylate and / or methacrylate," the term "(meth)allyl" means "allyl and / or methallyl," and the term "(meth)acrolein" means "acrolein and / or methacrolein." Furthermore, in this specification, the term "acid (salt)" means "acid and / or its salt." Examples of salts include alkali metal salts and alkaline earth metal salts, and specific examples include sodium salts and potassium salts.

[0015] ≪≪1. Surface protection film≫≫ The surface protection film according to the embodiment of the present invention has a substrate layer, a pressure-sensitive adhesive layer, and a release liner in this order.

[0016] The surface protection film according to an embodiment of the present invention may include any appropriate other layer, as long as it has a substrate layer, a pressure-sensitive adhesive layer, and a release liner in this order. Such other layer may be a single layer or two or more layers. Examples of such other layers include an antistatic layer. The antistatic layer may be provided in any appropriate position as long as the effects of the present invention are not impaired. The antistatic layer may be provided, for example, on the opposite side of the substrate layer from the pressure-sensitive adhesive layer, or between the substrate layer and the pressure-sensitive adhesive layer.

[0017] A surface protection film according to one embodiment of the present invention comprises a substrate layer, a pressure-sensitive adhesive layer, and a release liner in this order, with the release liner being the outermost layer.

[0018] A surface protection film according to one embodiment of the present invention comprises a substrate layer, an antistatic layer, an adhesive layer, and a release liner. A surface protection film according to one embodiment of the present invention comprises a substrate layer, an antistatic layer, an adhesive layer, and a release liner.

[0019] The thickness of the surface protection film according to the embodiment of the present invention is preferably 10 μm to 500 μm, more preferably 15 μm to 400 μm, even more preferably 20 μm to 350 μm, still more preferably 25 μm to 300 μm, particularly preferably 30 μm to 200 μm, and most preferably 35 μm to 100 μm.

[0020] Figure 1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention. In Figure 1, surface protection film 100 comprises a release liner 10, a pressure-sensitive adhesive layer 20, and a base layer 30. In the embodiment shown in Figure 1, release liner 10 and pressure-sensitive adhesive layer 20 are laminated directly to each other, and pressure-sensitive adhesive layer 20 and base layer 30 are laminated directly to each other. Release liner 10 can be peeled off when in use.

[0021] The surface protection film according to an embodiment of the present invention can be produced by any suitable method as long as the effects of the present invention can be exhibited. Examples of such production methods include a method in which a pressure-sensitive adhesive composition (e.g., an acrylic pressure-sensitive adhesive composition described below) capable of forming a pressure-sensitive adhesive layer is applied to a substrate layer, and if necessary, heating, irradiation with active energy rays (e.g., ultraviolet rays), drying, etc., is performed to form a pressure-sensitive adhesive layer on the substrate layer (a formation method generally referred to as the "direct method"), and a separately prepared release liner is laminated to the exposed surface of the pressure-sensitive adhesive layer; or a method in which a pressure-sensitive adhesive composition (e.g., an acrylic pressure-sensitive adhesive composition described below) capable of forming a pressure-sensitive adhesive layer is applied to any suitable substrate such as release paper, and if necessary, heating, irradiation with active energy rays (e.g., ultraviolet rays), drying, etc., is performed to form a pressure-sensitive adhesive layer on the substrate, and the pressure-sensitive adhesive layer formed on the substrate is transferred to the substrate layer (a formation method generally referred to as the "transfer method"), and a separately prepared release liner is laminated to the exposed surface of the pressure-sensitive adhesive layer. Of course, other methods may also be used for production.

[0022] Examples of the application method include a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, air knife coater, spray coater, comma coater, direct coater, and roll brush coater.

[0023] The surface protection film according to the embodiment of the present invention has a surface protection film having a thickness of b * The value of b of the entire surface protection film is typically 0.70 or more, may be 0.73 or more, or may be 0.75 or more. * If the value is within the above range, it is possible to impart a suitable yellowish tint to the appearance of the surface protective film, it is possible to prevent mistakes before peeling off the release liner, and it is possible to prevent forgetting to peel off the release liner during use. * The upper limit of the value is preferably as high as possible from the viewpoint of preventing mistakes before peeling off the release liner and preventing forgetting to peel off the release liner during use. * If the upper limit of the value is too high, the surface protection film may have too strong a yellow tint, which may affect the transmittance, and for example, may affect the optical inspection properties. * The upper limit of the value is preferably less than 5.00, may be less than 4.00, may be less than 2.50, or may be less than 1.50. Therefore, typically, the overall b * The value is typically 0.70 or greater, and may be 0.70 or greater but less than 5.00, 0.73 or greater but less than 4.00, 0.75 or greater but less than 2.50, or 0.75 or greater but less than 1.50.

[0024] The surface protection film according to an embodiment of the present invention typically has a transmittance of 85% or more for light having a wavelength of 550 nm throughout the surface protection film. When the transmittance of the surface protection film according to an embodiment of the present invention for light having a wavelength of 550 nm is within the above range, excellent optical inspectability can be achieved. From the viewpoint of excellent optical inspectability, the upper limit of the transmittance of the surface protection film according to an embodiment of the present invention for light having a wavelength of 550 nm is preferably as high as possible, and is ideally 100% or less, and may be less than 95%, or may be less than 90%. Therefore, the transmittance of the surface protection film according to an embodiment of the present invention for light having a wavelength of 550 nm throughout the surface protection film is typically 85% or more, and may be 85% to 100%, or may be 85% or more but less than 95%, or may be 85% or more but less than 90%.

[0025] The surface protective film according to the embodiment of the present invention is a laminate of the surface protective film with the release liner removed. * The value is typically less than 0.50, may be less than 0.45, may be less than 0.40, may be less than 0.35, or may be less than 0.30. * If the value is within the above range, adverse effects on the optical properties after the surface protection film according to the embodiment of the present invention is bonded to an optical device or the like can be suppressed. The laminate obtained by removing the release liner from the surface protection film according to the embodiment of the present invention is a laminate having a base layer and a pressure-sensitive adhesive layer, and examples thereof include a laminate consisting of a base layer and a pressure-sensitive adhesive layer, and a laminate consisting of a base layer, an antistatic layer, and a pressure-sensitive adhesive layer. The b of the laminate obtained by removing the release liner from the surface protection film * The lower limit of the value is the better from the viewpoint of suppressing the influence on the optical properties when used by sticking it to an adherend, and is ideally 0 or more, and may be 0.01 or more, 0.03 or more, 0.05 or more, or 0.10 or more. Therefore, typically, the surface protection film according to an embodiment of the present invention is a surface protection film having a thickness of b of a laminate obtained by removing the release liner from the surface protection film. *The value is typically less than 0.50, and may be 0 or more and less than 0.50, 0.01 or more and less than 0.45, 0.03 or more and less than 0.40, 0.05 or more and less than 0.35, or 0.10 or more and less than 0.30.

[0026] The surface protection film according to the embodiment of the present invention is a laminate of 15 sheets of the surface protection film. * The value is preferably 7.00 or more, may be 7.50 or more, or may be 8.00 or more. A laminate in which 15 sheets of surface protection films are laminated can be a model case of a surface protection film stored as a roll or a laminate. * If the value is within the above range, a suitable yellowish tint can be imparted to the appearance of the surface protection film in a laminated state, which can more effectively prevent the mix-up of surface protection films stored as rolls or laminates. * The upper limit of the value is, for example, less than 35.0, and may be less than 30.0, less than 25.0, less than 20.0, or less than 15.0. Therefore, the surface protection film according to the embodiment of the present invention is typically a laminate of 15 sheets of the surface protection film. * The value is preferably 7.00 or more and less than 30.0, may be 7.50 or more and less than 25.0, may be 8.00 or more and less than 20.0, or may be 8.00 or more and less than 15.0.

[0027] In the surface protection film according to an embodiment of the present invention, the reflectance of a laminate formed by laminating 15 of the surface protection films is preferably less than 40.0%. A laminate formed by laminating 15 surface protection films can be a model case of a surface protection film stored as a roll or a laminate. If the reflectance of the laminate formed by laminating 15 surface protection films is within the above range, it is possible to more effectively prevent mix-up of surface protection films stored as a roll or a laminate. The lower limit of the reflectance of the laminate formed by laminating 15 surface protection films is preferably 10.0% or more. Therefore, typically, in the surface protection film according to an embodiment of the present invention, the reflectance of a laminate formed by laminating 15 of the surface protection films is preferably less than 40.0%, and may be 10.0% or more but less than 40.0%.

[0028] <1-1. Release liner> The surface protection film according to an embodiment of the present invention includes a release liner.

[0029] The thickness of the release liner is preferably 1 μm to 300 μm, and may be 3 μm to 250 μm, 5 μm to 200 μm, 10 μm to 150 μm, 15 μm to 100 μm, or 20 μm to 80 μm.

[0030] Any appropriate release liner can be used as the release liner as long as the effects of the present invention can be achieved. Such a release liner typically includes a liner substrate. Examples of release liners include a release liner having a release layer provided on the surface of a liner substrate, and a release liner having a laminate layer of a polyolefin resin or the like provided on the surface of a liner substrate.

[0031] Examples of the liner substrate include plastic film, paper, metal film, and nonwoven fabric, and representatively, plastic film made of resin material. Examples of the plastic film as the liner substrate include polyester-based resin films such as polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film; polyimide-based resin films such as polyimide film; polyolefin-based resin films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, and polymethylpentene film; polyvinyl chloride-based resin films such as polyvinyl chloride film and vinyl chloride copolymer film; polyvinylidene chloride-based resin films such as polyvinylidene chloride film; urethane-based resin films such as polyurethane film; (meth)acrylic resin film; ethylene-vinyl acetate copolymer film; acetate resin film; polyamide-based resin film; polyvinyl alcohol film; polyethersulfone film; polycarbonate film; styrene-based films such as polystyrene film; polyarylate film; polyphenylene sulfide film; Among these, polyester resin films such as polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film are preferred in that they can more effectively exhibit the effects of the present invention.

[0032] The plastic film used as the liner substrate may be a recycled plastic film (recycled plastic film). The use of a recycled plastic film may facilitate the realization of the effects of the present invention. The recycled plastic film may be a recycled plastic film with a recycling rate of 100% by weight, or may be a recycled plastic film with a recycling rate of less than 100% by weight (i.e., a recycled plastic film made from a resin obtained from recycled resin and non-recycled resin). The recycling rate referred to here means the weight ratio of recycled resin to the total amount of resin material used as the raw material for the recycled plastic film.

[0033] The plastic film used as the liner substrate may be a dyed or colored plastic film. The use of such a dyed or colored plastic film can facilitate the development of the effects of the present invention. The dyeing or coloring may be carried out by any appropriate method, such as by using a dye or a pigment.

[0034] The release liner may include a layer other than the liner substrate. The release liner may include a release layer. One embodiment of the release liner includes a liner substrate and a release layer formed on one surface of the liner substrate.

[0035] The thickness of the release layer is, for example, 10 nm to 300 nm, may be 15 nm to 200 nm, may be 20 nm to 150 nm, or may be 25 nm to 100 nm.

[0036] The release layer may typically be a cured layer of a release agent composition containing a release agent, such as a silicone-based release agent, a fluorine-based release agent, a long-chain alkyl-based release agent, a fatty acid amide-based release agent, or silica powder.

[0037] One preferred embodiment of the release layer is a cured layer (hereinafter referred to as "silicone release layer") of a release agent composition containing a silicone-based release agent as a release agent (hereinafter referred to as "silicone release agent composition").

[0038] The silicone-based release agent may be, for example, a curable silicone material such as an addition reaction type, a condensation reaction type, an ultraviolet curable type, an electron beam curable type, or a solventless type, and is typically an addition reaction curable silicone material. The curable silicone material may also be a silicone-modified resin in which a reactive silicone is introduced into an organic resin such as a urethane resin, an epoxy resin, or an alkyd resin by graft polymerization or the like.

[0039] The addition reaction curable silicone material may be, for example, a polyorganosiloxane having a vinyl group or an alkenyl group in the molecule. The addition reaction curable silicone material may not have a hydrosilyl group. Examples of the alkenyl group include 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, 7-octenyl, 8-nonenyl, 9-decenyl, 10-undecenyl, and 11-dodecenyl. Examples of the polyorganosiloxane include polyalkylalkylsiloxanes such as polydimethylsiloxane, polydiethylsiloxane, and polymethylethylsiloxane; polyalkylarylsiloxanes; and copolymers of multiple Si atom-containing monomers such as poly(dimethylsiloxane-diethylsiloxane). A typical example is polydimethylsiloxane.

[0040] The silicone release agent composition may contain any suitable amount of other components, such as a suitable crosslinking agent, a curing catalyst, or a solvent, as long as the effects of the present invention are not impaired.

[0041] The release layer can be formed by any appropriate method as long as the effects of the present invention are not impaired. For example, a method in which a release agent composition is applied to a liner substrate, and then, if necessary, heated, irradiated with active energy rays (such as ultraviolet rays), or dried to form a release layer on the liner substrate can be mentioned. Of course, other methods may also be used.

[0042] Examples of the application method include a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, air knife coater, spray coater, comma coater, direct coater, and roll brush coater.

[0043] ≪1-2. Base material layer≫ The surface protection film according to the embodiment of the present invention includes a substrate layer. The substrate layer may be a single layer or may be two or more layers. The substrate layer is typically a single layer. The substrate layer may be stretched.

[0044] The thickness of the substrate layer is preferably 4 μm to 450 μm, more preferably 8 μm to 400 μm, still more preferably 12 μm to 350 μm, and particularly preferably 16 μm to 250 μm.

[0045] The surface of the base layer on which the adhesive layer is not applied may be subjected to a release treatment by adding a fatty acid amide-based additive, a polyethyleneimine-based additive, a long-chain alkyl-based additive, etc., in order to form a roll that is easy to unwind, or a release layer as described above may be provided.

[0046] Examples of the substrate layer include plastic films, paper, metal films, and nonwoven fabrics, and a representative example is a plastic film made of a resin material.

[0047] Examples of the plastic film include the plastic films described above as the liner substrate.

[0048] The substrate layer may contain any appropriate additives as needed. Examples of additives that may be contained in the substrate layer include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, number, and amount of additives that may be contained in the substrate layer may be appropriately set depending on the purpose.

[0049] <1-3. Adhesive layer> The surface protection film according to the embodiment of the present invention includes a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer may be a single layer or may be two or more layers. The pressure-sensitive adhesive layer is typically a single layer.

[0050] The thickness of the pressure-sensitive adhesive layer is preferably 0.5 μm to 100 μm, more preferably 1 μm to 70 μm, even more preferably 1.5 μm to 50 μm, still more preferably 2 μm to 40 μm, particularly preferably 2.5 μm to 30 μm, and most preferably 3 μm to 25 μm.

[0051] The adhesive constituting the adhesive layer may be any appropriate adhesive as long as it does not impair the effects of the present invention. As such an adhesive, a conventionally known adhesive may be used as an adhesive constituting the adhesive layer included in the surface protection film. As such an adhesive, preferably, at least one selected from the group consisting of an acrylic adhesive, a urethane adhesive, and a silicone adhesive is used, and preferably, an acrylic adhesive.

[0052] Hereinafter, an acrylic adhesive will be described as a typical example of the adhesive.

[0053] An acrylic pressure-sensitive adhesive is formed from an acrylic pressure-sensitive adhesive composition. In this way, an acrylic pressure-sensitive adhesive can be defined as something formed from an acrylic pressure-sensitive adhesive composition. This is because an acrylic pressure-sensitive adhesive becomes an acrylic pressure-sensitive adhesive when an acrylic pressure-sensitive adhesive composition undergoes a crosslinking reaction due to heating, ultraviolet irradiation, or the like, making it impossible and practical to directly identify an acrylic pressure-sensitive adhesive by its structure ("impossible / impractical circumstances"). Therefore, the definition of "something formed from an acrylic pressure-sensitive adhesive composition" appropriately identifies an acrylic pressure-sensitive adhesive as a "product."

[0054] The acrylic pressure-sensitive adhesive composition preferably contains an acrylic polymer and a crosslinking agent. The acrylic polymer is what can be called a base polymer in the field of acrylic pressure-sensitive adhesives. The acrylic polymer may be one type or two or more types.

[0055] The content of the acrylic polymer in the acrylic pressure-sensitive adhesive composition is preferably 60% by weight to 99.9% by weight, more preferably 65% ​​by weight to 99.9% by weight, even more preferably 70% by weight to 99.9% by weight, particularly preferably 75% by weight to 99.9% by weight, and most preferably 80% by weight to 99.9% by weight, calculated as solid content.

[0056] The weight average molecular weight of the acrylic polymer is preferably 100,000 to 2,500,000, more preferably 200,000 to 2,000,000, even more preferably 300,000 to 1,800,000, and particularly preferably 400,000 to 1,500,000, in order to further exert the effects of the present invention.

[0057] Any appropriate acrylic polymer can be used as the acrylic polymer as long as it does not impair the effects of the present invention. In terms of further enhancing the effects of the present invention, such an acrylic polymer is preferably an acrylic polymer formed by polymerization of a composition (M) containing a (meth)acrylic acid alkyl ester (component a) in which the alkyl group in the alkyl ester moiety has 4 to 12 carbon atoms, and at least one selected from the group consisting of a (meth)acrylic acid ester having an OH group and (meth)acrylic acid (component b). The components a and b may each independently be one type or two or more types.

[0058] Examples of (meth)acrylic acid alkyl esters in which the alkyl group in the alkyl ester moiety has 4 to 12 carbon atoms include n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, etc. Among these, in terms of being able to further exhibit the effects of the present invention, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-octyl (meth)acrylate are preferred, and n-butyl acrylate and 2-ethylhexyl acrylate are more preferred.

[0059] Examples of (meth)acrylic acid esters having an OH group include (meth)acrylic acid esters having an OH group such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, etc. Among these, hydroxyethyl (meth)acrylate and hydroxybutyl (meth)acrylate are preferred, and hydroxyethyl acrylate is more preferred, in terms of being able to further exhibit the effects of the present invention.

[0060] As the (meth)acrylic acid, acrylic acid is preferred in that the effects of the present invention can be more effectively exhibited.

[0061] The composition (M) may contain a copolymerizable monomer other than the components a and b. The copolymerizable monomer may be of one kind or of two or more kinds. Examples of such copolymerizable monomers include carboxyl group-containing monomers (excluding (meth)acrylic acid) such as itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and acid anhydrides thereof (for example, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride); amide group-containing monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide; amino group-containing monomers such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N Heterocycle-containing monomers such as vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphate group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate; cyclopentyl(meth) (meth)acrylic acid esters having an alicyclic hydrocarbon group, such as phenyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; aromatic ring-containing (meth)acrylates, such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxybenzyl (meth)acrylate (for example, m-phenoxybenzyl (meth)acrylate), thiophenoxybenzyl (meth)acrylate, and benzyl benzyl (meth)acrylate;Examples of (meth)acrylic acid alkoxyalkyl esters include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene; olefins and dienes such as ethylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

[0062] As the copolymerizable monomer, a polyfunctional monomer may also be used. A polyfunctional monomer refers to a monomer having two or more ethylenically unsaturated groups in one molecule. As the ethylenically unsaturated group, any appropriate ethylenically unsaturated group may be used as long as it does not impair the effects of the present invention. Examples of such ethylenically unsaturated groups include radically polymerizable functional groups such as a vinyl group, a propenyl group, an isopropenyl group, a vinyl ether group (vinyloxy group), and an allyl ether group (allyloxy group). Examples of polyfunctional monomers include hexanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, etc. Such polyfunctional monomers may be used alone or in combination of two or more.

[0063] The content of the (meth)acrylic acid alkyl ester (component a) in which the alkyl group in the alkyl ester moiety has 4 to 12 carbon atoms is preferably 30% by weight or more, more preferably 35% by weight to 99% by weight, even more preferably 40% by weight to 98% by weight, and particularly preferably 50% by weight to 95% by weight, relative to the total amount (100% by weight) of the monomer components constituting the acrylic polymer, in order to further exhibit the effects of the present invention.

[0064] The content of at least one selected from the group consisting of (meth)acrylic acid esters having an OH group and (meth)acrylic acid (component b) is preferably 1% by weight or more, more preferably 1 to 30% by weight, even more preferably 2 to 20% by weight, and particularly preferably 3 to 10% by weight, relative to the total amount (100% by weight) of the monomer components constituting the acrylic polymer, in order to further exhibit the effects of the present invention.

[0065] The composition (M) may contain any appropriate other components as long as the effects of the present invention are not impaired. Examples of such other components include a polymerization initiator, a chain transfer agent, and a solvent. The content of these other components may be any appropriate content as long as the effects of the present invention are not impaired.

[0066] The polymerization initiator may be a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc., depending on the type of polymerization reaction. Only one type of polymerization initiator may be used, or two or more types may be used.

[0067] A thermal polymerization initiator is preferably used when obtaining an acrylic polymer by solution polymerization. Examples of such a thermal polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propanol], 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propanol], 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propanol], 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propanol], 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl] ... azo initiators such as 2,2'-azobis(2-methylpropionamidine)dihydrochloride, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (VA-057, Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate, and di(2-ethylhexyl)peroxydicarbonate Examples of initiators include peroxide initiators such as di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butyl hydroperoxide, and hydrogen peroxide; redox initiators that combine peroxides with reducing agents, such as combinations of persulfates and sodium hydrogen sulfite and combinations of peroxides and sodium ascorbate; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0068] The photopolymerization initiator can be preferably used when obtaining an acrylic polymer by active energy ray polymerization. Examples of the photopolymerization initiator include a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, a photoactive oxime-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzyl-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, and a thioxanthone-based photopolymerization initiator.

[0069] Examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. Examples of photoactive oxime-based photopolymerization initiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Examples of benzoin-based photopolymerization initiators include benzoin. Examples of benzyl-based photopolymerization initiators include benzil. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexyl phenyl ketone. Examples of ketal-based photopolymerization initiators include benzil dimethyl ketal. Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0070] The amount of the polymerization initiator used can be set to any appropriate amount within a range that does not impair the effects of the present invention.

[0071] The acrylic pressure-sensitive adhesive composition may contain a crosslinking agent. Use of the crosslinking agent can improve the cohesive strength of the acrylic pressure-sensitive adhesive, thereby further enhancing the effects of the present invention. The crosslinking agent may be of one type or two or more types.

[0072] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents, and peroxides. In terms of being able to further exhibit the effects of the present invention, at least one crosslinking agent (component c) selected from the group consisting of isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and peroxides is preferred.

[0073] The isocyanate crosslinking agent can be a compound having two or more isocyanate groups (including isocyanate-regenerating polar groups in which the isocyanate group is temporarily protected by a blocking agent or oligomerization) per molecule. Examples of the isocyanate crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

[0074] Examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate; isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate HL), and isocyanurate of hexamethylene diisocyanate (e.g., manufactured by Tosoh Corporation, trade name: Coronate HX); Examples of the polyisocyanate include a trimethylolpropane adduct of rylene diisocyanate (e.g., manufactured by Mitsui Chemicals, Inc., trade name: Takenate D110N), a trimethylolpropane adduct of xylylene diisocyanate (e.g., manufactured by Mitsui Chemicals, Inc., trade name: Takenate D120N), a trimethylolpropane adduct of isophorone diisocyanate (e.g., manufactured by Mitsui Chemicals, Inc., trade name: Takenate D140N), a trimethylolpropane adduct of hexamethylene diisocyanate (e.g., manufactured by Mitsui Chemicals, Inc., trade name: Takenate D160N), and a trimethylolpropane adduct of tolylene diisocyanate (e.g., manufactured by Mitsui Chemicals, Inc., trade name: Takenate D101E); polyether polyisocyanates, polyester polyisocyanates, and adducts thereof with various polyols; and polyisocyanates multifunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc. Among these, aromatic isocyanates and alicyclic isocyanates are preferred because they can achieve a good balance between deformability and cohesive strength.

[0075] As the epoxy-based crosslinking agent, a multifunctional epoxy compound having two or more epoxy groups in one molecule can be used. Examples of the epoxy-based crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitol polyglycidyl ether. Examples of epoxy crosslinking agents include glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Commercially available epoxy crosslinking agents include, for example, "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0076] Examples of peroxides include dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxin)hexyne-3, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-mono(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy Neodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, t-butylperoxy-2-ethylhexyl carbonate, t-amylperoxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-hexanoate, t-butyl peroxypivalate, and t-hexyl peroxypivalate. Commercially available peroxides include, for example, the "Niper BMT" series and "Niper BW" series manufactured by Nippon Oil & Fats Corporation.

[0077] The content of the crosslinking agent in the acrylic pressure-sensitive adhesive composition may be any appropriate content within the range that does not impair the effects of the present invention. For example, in order to further exhibit the effects of the present invention, the content is preferably 0.01 to 20 parts by weight, more preferably 0.01 to 18 parts by weight, even more preferably 0.01 to 15 parts by weight, and particularly preferably 0.05 to 10 parts by weight, relative to the solid content (100 parts by weight) of the acrylic polymer.

[0078] The acrylic pressure-sensitive adhesive composition may contain any other appropriate components as long as they do not impair the effects of the present invention. Examples of such other components include polymer components other than acrylic polymers, crosslinking accelerators, crosslinking catalysts, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), antioxidants, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foil-like materials, UV absorbers, antioxidants, light stabilizers, nucleating agents, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts, etc.

[0079] ≪≪2. Optical and Electronic Devices≫≫ The surface protection film according to an embodiment of the present invention is typically attached to exposed surfaces of optical or electronic components to prevent scratches on the surfaces of the optical or electronic components during processing, assembly, inspection, transportation, etc. in the manufacturing process of optical or electronic devices, and can be suitably used for surface protection of optical or electronic components. The optical device according to an embodiment of the present invention includes a surface protection film according to an embodiment of the present invention. The electronic device according to an embodiment of the present invention includes a surface protection film according to an embodiment of the present invention. [Example]

[0080] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows. The term "parts" means "parts by weight" unless otherwise specified, and the term "%" means "% by weight" unless otherwise specified.

[0081] <B of the entire surface protection film * Value Measurement> Using a high-speed integrating sphere transmittance measuring instrument (manufactured by Murakami Color Research Laboratory, model "DOT-3C"), light was incident from the base layer side of the surface protection film obtained in the examples and comparative examples, and b *The values ​​were measured. * The values ​​refer to CIELab values. ○:b * Values ​​are 0.70 or greater. ×:b * Values ​​less than 0.70.

[0082] <Measurement of light transmittance at a wavelength of 550 nm across the entire surface protection film> Using a high-speed integrating sphere transmittance measuring instrument (manufactured by Murakami Color Research Laboratory, model "DOT-3C"), light was incident from the base layer side of the surface protection films obtained in the examples and comparative examples, and the transmittance of light with a wavelength of 550 nm was measured. ○: Transmittance of light with a wavelength of 550 nm is 85% or more. ×: The transmittance of light with a wavelength of 550 nm is less than 85%.

[0083] <b of the laminate excluding the release liner from the surface protection film * Value Measurement> The release liner was removed from the surface protection film obtained in the examples and comparative examples, and light was incident from the base layer side of the surface protection film using a high-speed integrating sphere transmittance measuring instrument (manufactured by Murakami Color Research Laboratory, model "DOT-3C"), and b * The values ​​were measured. * The values ​​refer to CIELab values. ○:b * Values ​​less than 0.50. ×:b * Value is 0.50 or more.

[0084] <b of a laminate consisting of 15 sheets of surface protection film * Value Measurement> Fifteen sheets of the surface protection films obtained in the examples and comparative examples were stacked, and light was incident from the base layer side of the surface protection film using a high-speed integrating sphere transmittance measuring instrument (manufactured by Murakami Color Research Laboratory, model "DOT-3C"), and b * The values ​​were measured. * The values ​​refer to CIELab values. ○:b * Value is 7.00 or greater. ×:b * Value is less than 7.00.

[0085] <Measurement of reflectance of a laminate consisting of 15 surface protection films> Fifteen of the surface protection films obtained in the examples and comparative examples were stacked and set in a spectrophotometer (Shimadzu Corporation, product name "UV-VIS ultraviolet-visible spectrophotometer SolidSpec3700"), and the 5° reflectance in the wavelength range of 300 nm to 800 nm was measured with incident light perpendicular to the base layer side of the surface protection film. ○: Reflectance is less than 40.0%. ×: Reflectance is 40.0% or more.

[0086] <Evaluation of the discernibility of surface protection films under storage conditions> A laminate made of 15 sheets of the surface protection film obtained in the Examples and Comparative Examples was lined up with a laminate made of 15 sheets of PET film (manufactured by Toray Industries, Inc., product name "Lumirror S10", thickness = 25 μm), and it was confirmed whether they could be distinguished by color when visually observed from the flat direction of the release liner side, and evaluated according to the following criteria. ○: The difference between the surface protection film laminates obtained in the examples and comparative examples and the PET film laminate can be distinguished. In other words, the surface protection film with ○ can prevent mix-ups before peeling off the release liner and can prevent forgetting to peel off the release liner during use. ×: The difference between the surface protection film laminates obtained in the Examples and Comparative Examples and the PET film laminate cannot be distinguished.

[0087] <Evaluation of optical inspectability> The HEX color code "#FDFAD7" and a 3cm diameter circle adjusted to 70% transparency were displayed on the display, and a laminate consisting of 15 sheets of the surface protection film obtained in the Examples and Comparative Examples was placed on top of it with the release liner side facing the display, and the visibility of the circle was evaluated visually according to the following criteria. HEX is an abbreviation for "Hexadecimal," and is a color code expressed in hexadecimal. ○: Circles are visible. ×: The circle is not visible.

[0088] [Production Example 1]: Preparation of acrylic adhesive composition (1) A four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser was charged with 96 parts by weight of 2-ethylhexyl acrylate (2EHA) and 4 parts by weight of 2-hydroxyethyl acrylate (HEA) as monomers, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 150 parts by weight of ethyl acetate. Nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 65°C, allowing the polymerization reaction to take place for 6 hours, yielding a solution of acrylic polymer A with a weight-average molecular weight of 540,000. Next, 4 parts by weight of an isocyanate crosslinking agent (trade name "Coronate HX", manufactured by Tosoh Corporation) was added to 100 parts by weight of acrylic polymer A (solid content) in terms of solid content, and 0.015 parts by weight of Envirizer OL-1 (manufactured by Tokyo Fine Chemical Co., Ltd.) was added as a catalyst, and the mixture was diluted with ethyl acetate to a total solid content of 30% by weight, thereby obtaining an acrylic pressure-sensitive adhesive composition (1).

[0089] [Production Example 2]: Preparation of a thermosetting silicone release agent solution A thermosetting silicone release agent solution was prepared by adding 100 parts by weight of a silicone release agent (KS-847H, manufactured by Shin-Etsu Chemical Co., Ltd.) and 3.3 parts by weight of a silicone curing catalyst (CAT-PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.), and diluting the mixture to 0.3% by weight with a solvent consisting of toluene, normal hexane, and methyl ethyl ketone in a weight ratio of 1:2:1.

[0090] [Example 1] (Preparation of release liner (1)) 1 g each of polyester dye yellow (manufactured by Katsuraya Fine Goods Co., Ltd.) and polyester dye orange (manufactured by Katsuraya Fine Goods Co., Ltd.) was added to 100 mL of hot water at 90°C and mixed well to prepare a dye. Separately, 2 g of a darkening accelerator (manufactured by Katsuraya Fine Goods, trade name "Darkening Accelerator") was added to 1900 mL of hot water at 90°C and mixed well to prepare an accelerator solution. The dye was added to the accelerating solution and mixed well to prepare a staining agent with a concentration of 2 g / L. A 25 μm thick PET film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") was immersed in the obtained dyeing agent for 10 seconds while keeping the temperature at 90° C. to prepare a dyed PET film. The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Mayer bar, and then heated and dried at 130°C for 30 seconds to produce a release liner (1) having a silicone-based release layer with a thickness of 0.1 μm. (Production of Surface Protection Film (1)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the side opposite the corona-treated side of a 38 μm-thick biaxially oriented polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C38") and heated at 130°C for 30 seconds to form a 21 μm-thick pressure-sensitive adhesive layer. Next, the silicone-based release layer side of the release liner (1) prepared above was attached to the film to obtain a surface protection film (1). The results are shown in Table 1.

[0091] [Example 2] (Preparation of release liner (2)) 2 g each of Polyester Dye Yellow (manufactured by Katsuraya Fine Goods Co., Ltd.) and Polyester Dye Orange (manufactured by Katsuraya Fine Goods Co., Ltd.) was added to 100 mL of hot water at 90°C and mixed well to prepare a dye. Separately, 4 g of a dark color accelerator (manufactured by Katsuraya Fine Goods, trade name "Dark Color Accelerator") was added to 1900 mL of hot water at 90°C and mixed well to prepare an accelerator solution. The dye was added to the accelerating solution and mixed well to prepare a staining agent with a concentration of 4 g / L. A 25 μm thick PET film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") was immersed in the obtained dyeing agent for 10 seconds while keeping the temperature at 90° C. to prepare a dyed PET film. The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Mayer bar, and then heated and dried at 130°C for 30 seconds to produce a release liner (2) having a silicone-based release layer with a thickness of 0.1 μm. (Production of surface protection film (2)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the side opposite the corona-treated side of a 38 μm-thick biaxially oriented polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C38") and heated at 130°C for 30 seconds to form a 21 μm-thick pressure-sensitive adhesive layer. Next, the silicone-based release layer side of the release liner (2) prepared above was attached to the coated film to obtain a surface protection film (2). The results are shown in Table 1.

[0092] [Example 3] (Preparation of release liner (3)) 4 g of Polyester Dye Yellow (manufactured by Katsuraya Fine Goods Co., Ltd.) was added to 100 mL of hot water at 90°C and mixed well to prepare a dye. Separately, 4 g of a darkening accelerator (manufactured by Katsuraya Fine Goods, trade name "Darkening Accelerator") was added to 1900 mL of hot water at 90°C and mixed well to prepare an accelerator solution. The dye was added to the accelerating solution and mixed well to prepare a staining agent with a concentration of 4 g / L. A 25 μm thick PET film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") was immersed in the obtained dyeing agent for 10 seconds while keeping the temperature at 90° C. to prepare a dyed PET film. The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Mayer bar, and then heated and dried at 130°C for 30 seconds to produce a release liner (3) having a silicone-based release layer with a thickness of 0.1 μm. (Production of Surface Protection Film (3)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the side opposite the corona-treated side of a 38 μm-thick biaxially oriented polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C38") and heated at 130°C for 30 seconds to form a 21 μm-thick pressure-sensitive adhesive layer. Next, the silicone-based release layer side of the release liner (3) prepared above was attached to the coated film to obtain a surface protection film (3). The results are shown in Table 1.

[0093] [Example 4] (Preparation of release liner (4)) 4 g each of Polyester Dye Yellow (manufactured by Katsuraya Fine Goods Co., Ltd.) and Polyester Dye Orange (manufactured by Katsuraya Fine Goods Co., Ltd.) was added to 100 mL of hot water at 90°C and mixed well to prepare a dye. Separately, 8 g of a darkening accelerator (manufactured by Katsuraya Fine Goods, trade name "Darkening Accelerator") was added to 1900 mL of hot water at 90°C and mixed well to prepare an accelerator solution. The dye was added to the accelerating solution and mixed well to prepare a staining agent with a concentration of 8 g / L. A 25 μm thick PET film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") was immersed in the obtained dyeing agent for 60 seconds while keeping the temperature at 90° C. to prepare a dyed PET film. The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Mayer bar, and then heated and dried at 130°C for 30 seconds to produce a release liner (4) having a silicone-based release layer with a thickness of 0.1 μm. (Production of Surface Protection Film (4)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the side opposite the corona-treated side of a 38 μm-thick biaxially oriented polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C38") and heated at 130°C for 30 seconds to form a 21 μm-thick pressure-sensitive adhesive layer. Next, the silicone-based release layer side of the release liner (4) prepared above was attached to the coated film to obtain a surface protection film (4). The results are shown in Table 1.

[0094] [Comparative Example 1] (Preparation of release liner (C1)) The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to a 25 μm-thick polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C25") using a Mayer bar, and the film was dried by heating at 130°C for 30 seconds to produce a release liner (C1) with a 0.1 μm-thick silicone-based release layer. (Production of surface protection film (C1)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the side opposite the corona-treated side of a 38 μm-thick biaxially oriented polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C38") and heated at 130°C for 30 seconds to form a 21 μm-thick pressure-sensitive adhesive layer. Next, the silicone-based release layer side of the release liner (C1) prepared above was attached to the film to obtain a surface protection film (C1). The results are shown in Table 1.

[0095] Comparative Example 2 (Preparation of release liner (C2)) The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to a 50 μm thick polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C50") using a Meyer bar, and then heated and dried at 130°C for 30 seconds to produce a release liner (C2) with a 0.1 μm thick silicone-based release layer. (Production of surface protection film (C2)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the side opposite the corona-treated side of a 38 μm-thick biaxially oriented polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C38") and heated at 130°C for 30 seconds to form a 21 μm-thick pressure-sensitive adhesive layer. Next, the silicone-based release layer side of the release liner (C2) prepared above was attached to the coated film to obtain a surface protection film (C2). The results are shown in Table 1.

[0096] Comparative Example 3 (Preparation of release liner (C3)) 4 g of Polyester Dyblon (manufactured by Katsuraya Fine Goods Co., Ltd.) was added to 100 mL of hot water at 90°C and mixed well to prepare a dye. Separately, 4 g of a dark color accelerator (manufactured by Katsuraya Fine Goods, trade name "Dark Color Accelerator") was added to 1900 mL of hot water at 90°C and mixed well to prepare an accelerator solution. The dye was added to the accelerating solution and mixed well to prepare a staining agent with a concentration of 4 g / L. A 25 μm thick PET film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") was immersed in the obtained dyeing agent for 2 minutes while keeping the temperature at 90° C. to prepare a dyed PET film. The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Mayer bar, and then heated at 130°C for 30 seconds to dry, producing a release liner (C3) with a silicone-based release layer 0.1 μm thick. (Production of surface protection film (C3)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the side opposite the corona-treated side of a 38 μm-thick biaxially oriented polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C38") and heated at 130°C for 30 seconds to form a 21 μm-thick pressure-sensitive adhesive layer. Next, the silicone-based release layer side of the release liner (C3) prepared above was attached to the coated film to obtain a surface protection film (C3). The results are shown in Table 1.

[0097] Comparative Example 4 (Preparation of release liner (C4)) The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to a 25 μm thick polyester film (manufactured by Mitsubishi Chemical, product name "Diafoil T100C25") using a Meyer bar, and the film was dried by heating at 130°C for 30 seconds to produce a release liner (C4) with a 0.1 μm thick silicone-based release layer. (Preparation of polyethylene film) A polyethylene resin (manufactured by Tosoh Corporation, product name "Nipolon Hard 4000", high-density polyethylene produced by a low-pressure slurry process) was fed into a T-die molding machine and extruded to produce a polyethylene film with a thickness of 100 μm. One side of the obtained polyethylene film was subjected to corona treatment using a corona treatment device (manufactured by Kasuga Electric Co., Ltd., table-type treatment station, high-frequency power supply AGI-020SF) at an output of 0.3 kW and a treatment speed of 2 m / min. (Production of surface protection film (C4)) The acrylic pressure-sensitive adhesive composition (1) obtained in Production Example 1 was applied to the silicone release layer side of the release liner (C4) prepared above, and heated at 130°C for 30 seconds to form a pressure-sensitive adhesive layer with a thickness of 21 µm. Next, the pressure-sensitive adhesive layer was attached to the corona-treated surface of the polyethylene film prepared above to obtain a surface protection film (C4). The results are shown in Table 1.

[0098] [Table 1] [Industrial Applicability]

[0099] The surface protection film of the present invention can be used for any suitable purpose, such as preventing scratches on the surfaces of optical or electronic components during processing, assembly, inspection, transportation, etc. in the manufacturing process of optical or electronic devices. [Explanation of symbols]

[0100] 10 Release liner 20 adhesive layer 30 Base material layer 100 Surface Protection Film

Claims

1. A surface protection film having a base layer, a pressure-sensitive adhesive layer, and a release liner in this order, b of the entire surface protection film * The value is 0.70 or more, the transmittance of the entire surface protective film at a wavelength of 550 nm is 85% or more, b of the laminate obtained by removing the release liner from the surface protective film * a value of less than 0.50; Surface protection film.

2. The laminate b of 15 sheets of the surface protection film * The surface protection film according to claim 1 , wherein the value is 7.00 or more.

3. The surface protection film according to claim 1 , wherein a laminate of 15 of the surface protection films has a reflectance of less than 40.0%.

4. 2. The surface protection film according to claim 1, wherein the thickness of the surface protection film is 10 μm to 500 μm.

5. 2. The surface protection film according to claim 1, wherein the release liner has a thickness of 1 μm to 300 μm.

6. An optical device comprising the surface protection film according to any one of claims 1 to 5.

7. An electronic device comprising the surface protection film according to any one of claims 1 to 5.

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