Surface protective film, optical device, and electronic device

Abstract

Provided are a surface protective film, an optical device, and an electronic device, the surface protective film having a substrate layer, an adhesive layer, and a release liner in this order, being capable of preventing the release liner from being mistakenly taken before being peeled off, being capable of preventing the release liner from being forgotten to be peeled off during use, and having excellent optical inspection properties. The optical device and the electronic device comprise the surface protection film. A surface protective film according to an embodiment of the present invention has a substrate layer, an adhesive layer, and a release liner in this order, the b * value of the entire surface protective film being 0.70 or more, the transmittance of light having a wavelength of 550 nm being 85% or more, and the b * value of a laminate obtained by removing the release liner from the surface protective film being less than 0.50.

Description

TECHNICAL FIELD

[0001] The present application relates to a surface protective film. The present application also relates to an optical device and an electronic device including the above-described surface protective film. BACKGROUND

[0002] A surface protective film is provided on the surface of an optical member such as a film, a glass material, an optical device such as a display or a camera, and an electronic device, for the purpose of surface protection, imparting impact resistance, and the like.

[0003] As a surface protective film, there are a film that is temporarily and temporarily adhered in a state before use in assembly, processing, transportation, and the like of a device, and is peeled again before use of the device (a film used as an engineering material), and a film that is used while remaining adhered to the surface of a device at the time of use of the device (a film for the purpose of permanent adhesion) (for example, see Patent Document 1).

[0004] Typically, a surface protective film has an adhesive layer on a main surface of a film substrate, and a release liner is provided on the surface of the adhesive layer. When the surface protective film is used, after the release liner is peeled, the exposed adhesive layer is adhered to the surface of an adherend to be protected (for example, see Patent Document 2).

[0005] The surface protective film before use (before the release liner is peeled) is usually stored in the form of the same roll or stack, and for example, if different types of surface protective films are arranged and placed, it is sometimes difficult to distinguish them from each other by visual observation, and there is a possibility of taking the wrong one.

[0006] In addition, the appearance of the surface protective film before and after peeling of the release liner is difficult to distinguish by visual observation. Therefore, at the time of use of the surface protective film, there is a problem that the release liner is forgotten to be peeled.

[0007] Further, the surface protective film can be used for the purpose of protecting the surface of an optical device or the like, imparting impact resistance, and the like, and thus it is required to be free from foreign matter or the like. Therefore, it is required to be good in optical inspection by precise optical inspection.

[0008] PRIOR ART DOCUMENTS

[0009] PATENT DOCUMENTS

[0010] Patent Document 1: Japanese Patent No. 3518677

[0011] Patent Document 2: Japanese Patent No. 6249617 SUMMARY

[0012] The present application is to provide a surface protective film which has a substrate layer, an adhesive layer, and a release liner in this order, which can prevent mistaken handling before the release liner is peeled off, can prevent forgetting to peel off the release liner at the time of use, and is excellent in optical checking property. Further, the present application is to provide an optical device and an electronic device each of which contains the above-described surface protective film.

[0013] The present inventors have made intensive studies in order to solve the above-described problems. As a result, it has been found that the problems of the present application can be solved if the hue and the transmittance are appropriately adjusted for the entire surface protective film and the laminate obtained by removing the release liner from the surface protective film. In particular, it has been found that the problems of the present application can be solved if the b * a * b * value in the color system, particularly the b * value relating to the yellow hue, is adjusted to an appropriate range, and the transmittance is adjusted to an appropriate range.

[0014] [1] The surface protective film of the embodiment of the present application has a substrate layer, an adhesive layer, and a release liner in this order, the b * value of the entire surface protective film is 0.70 or greater, the transmittance of light having a wavelength of 550 nm of the entire surface protective film is 85% or greater, and the b * value of a laminate obtained by removing the release liner from the surface protective film is less than 0.50.

[0015] [2] In the surface protective film described in the above [1], the b * value of a laminate obtained by stacking 15 of the above-described surface protective films can be 7.00 or greater.

[0016] [3] In the surface protective film described in the above [1] or [2], the reflectance of a laminate obtained by stacking 15 of the above-described surface protective films can be less than 40.0%.

[0017] [4] In the surface protective film described in any one of the above [1] to [3], the thickness of the above-described surface protective film can be 10 μm to 500 μm.

[0018] [5] In the surface protective film described in any one of the above [1] to [4], the thickness of the above-described release liner can be 1 μm to 300 μm.

[0019] [6] The optical device of the embodiment of the present application contains the surface protective film described in any one of the above [1] to [5].

[0020] [7] The electronic device of the embodiment of the present application contains the surface protective film described in any one of the above [1] to [5].

[0021] Effects of Invention

[0022] According to the present application, a surface protective film which has a substrate layer, an adhesive layer, and a release liner in this order, which can prevent mistaken taking before peeling the release liner, which can prevent forgetting to peel the release liner at the time of use, and which is excellent in optical checking property, can be provided. Further, an optical device and an electronic device including the above-described surface protective film can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic cross-sectional view of a surface protective film of one embodiment of the present application. DETAILED DESCRIPTION

[0024] In the present specification, in the case where "(meth)acrylic acid" is expressed, "acrylic acid and / or methacrylic acid" is meant, in the case where "(meth)acrylate" is expressed, "acrylate and / or methacrylate" is meant, in the case where "(meth)allyl" is expressed, "allyl and / or methallyl" is meant, and in the case where "(meth)acrolein" is expressed, "acrolein and / or methacrolein" is meant. Further, in the present specification, in the case where "acid (salt)" is expressed, "acid and / or a salt thereof" is meant. As the salt, for example, an alkali metal salt, an alkaline earth metal salt, specifically, for example, a sodium salt, a potassium salt, and the like can be mentioned.

[0025] 《《1. Surface protective film》

[0026] The surface protective film of one embodiment of the present application has a substrate layer, an adhesive layer, and a release liner in this order.

[0027] The surface protective film of one embodiment of the present application can include any appropriate other layer as long as it has a substrate layer, an adhesive layer, and a release liner in this order. Such an other layer can be only one layer, or two or more layers. As such an other layer, for example, an antistatic layer can be mentioned. The antistatic layer can be provided at any appropriate position within a range not impairing the effects of the present application. The antistatic layer can be provided, for example, on the side of the substrate layer opposite to the adhesive layer, between the substrate layer and the adhesive layer.

[0028] The surface protective film of one embodiment of the present application has a substrate layer, an adhesive layer, and a release liner in this order, and the release liner is the outermost layer.

[0029] The surface protective film of one embodiment of the present application is composed of a substrate layer, an adhesive layer, and a release liner. The surface protective film of one embodiment of the present application is composed of a substrate layer, an antistatic layer, an adhesive layer, and a release liner.

[0030] The surface protective film of the embodiment of the present application preferably has a thickness of 10 μm to 500 μm, more preferably 15 μm to 400 μm, further preferably 20 μm to 350 μm, further preferably 25 μm to 300 μm, particularly preferably 30 μm to 200 μm, most preferably 35 μm to 100 μm.

[0031] Figure 1 is a schematic cross-sectional view of a surface protective film of an embodiment of the present application. In Figure 1 , the surface protective film 100 has a release liner 10, an adhesive layer 20, and a base material layer 30. Figure 1 In the embodiment shown, the release liner 10 is directly laminated with the adhesive layer 20, and the adhesive layer 20 is directly laminated with the base material layer 30. The release liner 10 can be peeled off and used at the time of use.

[0032] The surface protective film of the embodiment of the present application can be manufactured by any appropriate method within a range in which the effects of the present application can be exhibited. As such a manufacturing method, for example, the following methods can be listed: a method in which an adhesive composition that forms an adhesive layer (for example, the acrylic adhesive composition described later) is applied to a base material layer, and heating, active energy ray (ultraviolet rays or the like) irradiation, drying, or the like is performed as necessary to form an adhesive layer on the base material layer (a formation method generally referred to as "direct method"), and a release liner prepared separately is attached to the exposed surface of the adhesive layer; a method in which an adhesive composition that forms an adhesive layer (for example, the acrylic adhesive composition described later) is applied to an arbitrary appropriate base material such as a release paper, and heating, active energy ray (ultraviolet rays or the like) irradiation, drying, or the like is performed as necessary to form an adhesive layer on the base material, the adhesive layer formed on the base material is transferred to a base material layer (a formation method generally referred to as "transfer method"), and a release liner prepared separately is attached to the exposed surface of the adhesive layer. Of course, the surface protective film can also be manufactured by a method other than these methods.

[0033] As the method of application described above, for example, the following methods can be listed: a gravure coater, a reverse roll coater, a contact roll coater, a dip roll coater, a bar coater, a knife coater, an air knife coater, a spray coater, a doctor blade coater, a direct coater, a brush roll coater, or the like.

[0034] In the case of the surface protective film of the embodiment of the present application, the b * value of the entire surface protective film is typically 0.70 or greater, can be 0.73 or greater, and can be 0.75 or greater. If the b *The value of b* of the surface protective film as a whole is preferably 0.70 or greater, more preferably 0.73 or greater, and even more preferably 0.75 or greater. The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less. * The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less. * The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less. * The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less. For example, the upper limit of the value of b* of the surface protective film as a whole is preferably less than 5.00, can be less than 4.00, can be less than 2.50, and can be less than 1.50. Thus, typically, the value of b* of the surface protective film as a whole according to the embodiment of the present application is typically 0.70 or greater, can be 0.70 or greater and less than 5.00, can be 0.73 or greater and less than 4.00, can be 0.75 or greater and less than 2.50, and can be 0.75 or greater and less than 1.50. * The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less. For example, the upper limit of the value of b* of the surface protective film as a whole is preferably less than 5.00, can be less than 4.00, can be less than 2.50, and can be less than 1.50. Thus, typically, the value of b* of the surface protective film as a whole according to the embodiment of the present application is typically 0.70 or greater, can be 0.70 or greater and less than 5.00, can be 0.73 or greater and less than 4.00, can be 0.75 or greater and less than 2.50, and can be 0.75 or greater and less than 1.50.

[0035] The value of b* of the surface protective film as a whole is preferably 0.70 or greater, more preferably 0.73 or greater, and even more preferably 0.75 or greater. The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less.

[0036] The value of b* of the surface protective film as a whole is preferably 0.70 or greater, more preferably 0.73 or greater, and even more preferably 0.75 or greater. The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less. For example, the upper limit of the value of b* of the surface protective film as a whole is preferably less than 5.00, can be less than 4.00, can be less than 2.50, and can be less than 1.50. Thus, typically, the value of b* of the surface protective film as a whole according to the embodiment of the present application is typically 0.70 or greater, can be 0.70 or greater and less than 5.00, can be 0.73 or greater and less than 4.00, can be 0.75 or greater and less than 2.50, and can be 0.75 or greater and less than 1.50. * The upper limit of the value of b* of the surface protective film as a whole is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 2.50 or less. The upper limit of the value of b* of the surface protective film as a whole is preferably 1.50 or less. For example, the upper limit of the value of b* of the surface protective film as a whole is preferably less than 5.00, can be less than 4.00, can be less than 2.50, and can be less than 1.50. Thus, typically, the value of b* of the surface protective film as a whole according to the embodiment of the present application is typically 0.70 or greater, can be 0.70 or greater and less than 5.00, can be 0.73 or greater and less than 4.00, can be 0.75 or greater and less than 2.50, and can be 0.75 or greater and less than 1.50. *When the value is within the above range, adverse effects on optical properties after the surface protective film of the embodiment of the present application is attached to optical devices and the like can be suppressed. Note that the laminate obtained by removing the release liner from the surface protective film of the embodiment of the present application is a laminate having a base material layer and an adhesive layer, and for example, a laminate composed of a base material layer and an adhesive layer, a laminate composed of a base material layer, an antistatic layer, and an adhesive layer can be cited. From the viewpoint of suppressing effects on optical properties when attached to an adherend, the b * The lower the lower limit value of the value is, the better, and desirably, it is 0 or more, can be 0.01 or more, can be 0.03 or more, can be 0.05 or more, or can be 0.10 or more. Thus, typically with respect to the surface protective film of the embodiment of the present application, the b * The value is typically less than 0.50, can be 0 or more and less than 0.50, can be 0.01 or more and less than 0.45, can be 0.03 or more and less than 0.40, can be 0.05 or more and less than 0.35, or can be 0.10 or more and less than 0.30.

[0037] With respect to the surface protective film of the embodiment of the present application, the b * The value is preferably 7.00 or more, can be 7.50 or more, or can be 8.00 or more. The laminate of 15 surface protective films can be a typical example of the surface protective film stored in the form of a roll or a laminate. If the b * When the value is within the above range, a moderate yellow tint can be imparted to the appearance of the surface protective film in the stacked state, and thus, further prevention of mistaken taking of the surface protective film stored in the form of a roll or a laminate is possible. The b * The upper limit value of the value is, for example, less than 35.0, can be less than 30.0, can be less than 25.0, can be less than 20.0, or can be less than 15.0. Thus, typically with respect to the surface protective film of the embodiment of the present application, the b * The value is preferably 7.00 or more and less than 30.0, can be 7.50 or more and less than 25.0, can be 8.00 or more and less than 20.0, or can be 8.00 or more and less than 15.0.

[0038] The reflectance of the laminate of 15 sheets of the surface protective film according to the embodiment of the present application is preferably 40.0% or less. The laminate of 15 sheets of the surface protective film is a typical example of the surface protective film stored in the form of a roll or a laminate. If the reflectance of the laminate of 15 sheets of the surface protective film described above is within the range described above, it is possible to further prevent the surface protective film stored in the form of a roll or a laminate from being taken by mistake. The lower limit of the reflectance of the laminate of 15 sheets of the surface protective film described above is preferably 10.0% or more. Thus, typically, the reflectance of the laminate of 15 sheets of the surface protective film according to the embodiment of the present application is preferably 40.0% or less and can be 10.0% or more and less than 40.0%.

[0039] <1-1. Release Liner>

[0040] The surface protective film according to the embodiment of the present application includes a release liner.

[0041] The thickness of the release liner is preferably 1 μm to 300 μm, can be 3 μm to 250 μm, can be 5 μm to 200 μm, can be 10 μm to 150 μm, can be 15 μm to 100 μm, or can be 20 μm to 80 μm.

[0042] As the release liner, any appropriate release liner can be used within a range in which the effects of the present application can be exhibited. Such a release liner typically includes a liner base material. Examples of the release liner include a release liner in which a release layer is provided on the surface of the liner base material and a release liner in which a lamination layer of a polyolefin-based resin or the like is provided on the surface of the liner base material.

[0043] As the liner base material, for example, a plastic film, paper, a metal film, and a nonwoven fabric can be used, and typically, a plastic film formed of a resin material can be used. As the plastic film used as the liner base material, for example, a polyester-based resin film such as a polyethylene terephthalate film, a polyethylene naphthalate film, and a polybutylene terephthalate film; a polyimide-based resin film such as a polyimide film; a polyolefin-based resin film such as a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, and a polymethylpentene film; a polyvinyl chloride-based resin film such as a polyvinyl chloride film and a vinyl chloride copolymer film; a polyvinylidene chloride-based resin film such as a polyvinylidene chloride film; a urethane-based resin film such as a polyurethane film; a (meth)acrylic resin film; an ethylene-vinyl acetate copolymer film; an acetate resin film; a polyamide-based resin film; a polyvinyl alcohol film; a polyethersulfone film; a polycarbonate film; a styrene-based resin film such as a polystyrene film; a polyarylate film; and a polyphenylene sulfide film can be used. Among these, from the aspect of more effectively exhibiting the effects of the present application, a polyester-based resin film such as a polyethylene terephthalate film, a polyethylene naphthalate film, and a polybutylene terephthalate film is preferred.

[0044] The plastic film as the liner base material can be a recycled plastic film (recycled plastic film). If a recycled plastic film is used, the effects of the present application can be easily exhibited. Note that the recycled plastic film can be a recycled plastic film having a recycling rate of 100% by weight, or a recycled plastic film having a recycling rate of less than 100% by weight (i.e., a recycled plastic film using a resin obtained from a recycled resin and a non-recycled resin as a raw material). Note that the recycling rate here refers to the weight proportion of the recycled resin in the total amount of the resin material used as a raw material for the recycled plastic film.

[0045] The plastic film as the liner base material can be a dyed or colored plastic film. If such a dyed or colored plastic film is used, the effects of the present application can be easily exhibited. The dyeing or coloring can be performed by any appropriate method using a dye, a pigment, or the like.

[0046] The release liner can have a layer other than the liner base material. The release liner can have a release layer. One embodiment of the release liner includes a liner base material and a release layer formed on one face of the liner base material.

[0047] The thickness of the release layer is, for example, 10 nm to 300 nm, can be 15 nm to 200 nm, can be 20 nm to 150 nm, or can be 25 nm to 100 nm.

[0048] The release layer is typically a cured layer of a release agent composition containing a release agent. As the release agent, various release agents 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, and silica powder can be used, for example.

[0049] One preferred embodiment of the release layer is a cured layer of a release agent composition containing a silicone-based release agent as a release agent (hereinafter referred to as "silicone release agent composition") (hereinafter referred to as "silicone release layer").

[0050] The silicone-based release agent can be, for example, an addition reaction type, a condensation reaction type, an ultraviolet curing type, an electron beam curing type, a solventless type, or the like, and is typically an addition reaction curing type silicone material. In addition, the cured silicone material can be a silicone-modified resin obtained by graft polymerization or the like of a reactive silicone to an organic resin such as a urethane resin, an epoxy resin, an alkyd resin, or the like.

[0051] As the addition reaction-curable silicone material, for example, a polyorganosiloxane having a vinyl group or an alkenyl group in the molecule can be mentioned. The addition reaction-curable silicone material can also not have a silicon hydride group. As the alkenyl group, for example, 3-butenyl group, 4-pentenyl group, 5-hexenyl group, 6-heptenyl group, 7-octenyl group, 8-nonenyl group, 9-decenyl group, 10-undecenyl group, 11-dodecenyl group can be mentioned. As the polyorganosiloxane, for example, polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane and the like polyalkylalkylsiloxane; polyalkylarylsiloxane; poly(dimethylsiloxane-diethylsiloxane) and the like copolymer of various Si atom-containing monomers, and polydimethylsiloxane are mentioned.

[0052] The silicone release agent composition can contain other components such as a crosslinking agent, a curing catalyst, a solvent and the like in an arbitrary appropriate amount without impairing the effects of the present application.

[0053] The release layer can be formed in an arbitrary appropriate method without impairing the effects of the present application. As such a method, for example, a method in which the release agent composition is applied to the liner substrate, and heating, active energy ray (ultraviolet ray and the like) irradiation, drying and the like are performed as necessary to form the release layer on the liner substrate can be mentioned. Of course, it can also be formed by a method other than the above.

[0054] As the method of the above-mentioned application, for example, a method such as a gravure coater, a reverse roll coater, a contact roll coater, a dip roll coater, a bar coater, a knife coater, an air knife coater, a spray coater, a hopper coater, a direct coater, a roll brush coater and the like can be mentioned.

[0055] "1-2. Substrate Layer"

[0056] The surface protective film of the embodiment of the present application contains a substrate layer. The substrate layer can be only one layer, or two or more layers. The substrate layer is typically one layer. The substrate layer can also be stretched.

[0057] The thickness of the substrate layer is preferably 4 μm to 450 μm, more preferably 8 μm to 400 μm, further preferably 12 μm to 350 μm, particularly preferably 16 μm to 250 μm.

[0058] For the purpose of forming a roll body which is easy to unroll and the like, the surface of the substrate layer to which the adhesive layer is not attached can be subjected to a release treatment with a fatty acid amide-based additive, a polyethylene imine-based additive, a long-chain alkyl-based additive and the like, and a release layer as described above can be provided.

[0059] As the substrate layer, for example, a plastic film, paper, a metal film, a nonwoven fabric can be mentioned, and a plastic film formed of a resin material is typically mentioned.

[0060] As the plastic film, for example, the plastic film described above as the liner base material can be exemplified.

[0061] The base material layer can contain any appropriate additive as needed. As the additive that can be contained in the base material layer, for example, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a filler, a pigment, and the like can be exemplified. The kind, number, and amount of the additive that can be contained in the base material layer can be appropriately set according to the purpose.

[0062] "1-3. Adhesive layer"

[0063] The surface protective film of the embodiment of the present application contains an adhesive layer. The adhesive layer can be only one layer, and can be two or more layers. The adhesive layer is typically one layer.

[0064] The thickness of the adhesive layer is preferably 0.5 μm to 100 μm, more preferably 1 μm to 70 μm, further preferably 1.5 μm to 50 μm, further preferably 2 μm to 40 μm, particularly preferably 2.5 μm to 30 μm, and most preferably 3 μm to 25 μm.

[0065] The adhesive that constitutes the adhesive layer can employ any appropriate adhesive within a range that does not impair the effects of the present application. As such an adhesive, an adhesive that has been conventionally known as an adhesive that constitutes the adhesive layer contained in the surface protective film can be employed. As such an adhesive, at least one selected from the group consisting of an acrylic adhesive, a urethane adhesive, and a silicone adhesive is preferable, and an acrylic adhesive is particularly preferable.

[0066] Hereinafter, as a representative example of the adhesive, an acrylic adhesive will be described.

[0067] The acrylic adhesive is formed of an acrylic adhesive composition. The acrylic adhesive can be defined as a substance formed of an acrylic adhesive composition as such. The reason for this is that, in the case of the acrylic adhesive, the acrylic adhesive composition becomes the acrylic adhesive by undergoing a cross-linking reaction or the like through heating, ultraviolet irradiation, or the like, and thus it is not possible, and furthermore, it is completely impractical, to directly specify the acrylic adhesive by its structure. Due to the above-described situation ("impossible and impractical situation"), the acrylic adhesive is appropriately specified as a "substance" by being defined as "a substance formed of an acrylic adhesive composition".

[0068] The acrylic adhesive composition preferably contains an acrylic polymer and a cross-linking agent. The acrylic polymer can be referred to as a so-called base polymer in the field of the acrylic adhesive. The acrylic polymer can be only one kind, and can be two or more kinds.

[0069] The content ratio of the acrylic polymer in the acrylic adhesive composition is preferably 60 to 99.9% by weight, more preferably 65 to 99.9% by weight, further preferably 70 to 99.9% by weight, particularly preferably 75 to 99.9% by weight, and most preferably 80 to 99.9% by weight, based on the solid content.

[0070] The weight average molecular weight of the acrylic polymer is preferably 100 to 2,500,000, more preferably 200 to 2,000,000, further preferably 300 to 1,800,000, and particularly preferably 400 to 1,500,000, from the viewpoint of more effectively exhibiting the effects of the present application.

[0071] As the acrylic polymer, any appropriate acrylic polymer can be used within a range not impairing the effects of the present application. As such an acrylic polymer, it is preferable that the acrylic polymer be formed by polymerization of a composition (M) containing an alkyl (meth)acrylate having 4 to 12 carbon atoms in the alkyl group of the alkyl ester moiety (a component) and at least one selected from the group consisting of (meth)acrylates having an OH group and (meth)acrylic acid (b component), from the viewpoint of more effectively exhibiting the effects of the present application. The a component and the b component can each independently be one or two or more.

[0072] As the alkyl (meth)acrylate having 4 to 12 carbon atoms in the alkyl group of the alkyl ester moiety, for example, there can be mentioned n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-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, and the like. Among these, from the viewpoint of more effectively exhibiting the effects of the present application, it is preferable that the alkyl (meth)acrylate be n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, and more preferable that the alkyl (meth)acrylate be n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate.

[0073] As the (meth)acrylate having an OH group, for example, there can be mentioned (meth)acrylic acid hydroxyethyl ester, (meth)acrylic acid hydroxypropyl ester, (meth)acrylic acid hydroxybutyl ester, and the like. Among these, from the viewpoint of more effectively exhibiting the effects of the present application, it is preferable that the (meth)acrylate be (meth)acrylic acid hydroxyethyl ester or (meth)acrylic acid hydroxybutyl ester, and more preferable that the (meth)acrylate be (meth)acrylic acid hydroxyethyl ester.

[0074] As the (meth)acrylic acid, acrylic acid is preferred from the viewpoint of more exhibiting the effects of the present application.

[0075] The composition (M) can contain a copolymerizable monomer other than the a component and the b component. The copolymerizable monomer can be only one or two or more. As such a copolymerizable monomer, for example, carboxyl group-containing monomers (excluding (meth)acrylic acid) such as itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, acid anhydrides thereof (for example, maleic anhydride, itaconic anhydride, and the like) and the like; amide group-containing monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and the like; amino group-containing monomers such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, and the like; epoxy group-containing monomers such as glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and the like; cyano group-containing monomers such as acrylonitrile, methacrylonitrile, and the like; heterocyclic ring-containing monomers such as N-vinyl-2-pyrrolidone, (meth)acryloyl morpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, vinyl oxazole, and the like; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; imide group-containing monomers such as cyclohexyl maleimide, isopropyl maleimide, and the like; isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate; (meth)acrylic acid esters having an alicyclic hydrocarbon group such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and the like; (meth)acrylic acid esters containing an aromatic ring such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxybenzyl (meth)acrylate (for example, m-phenoxybenzyl (meth)acrylate), phenylthioxybenzyl (meth)acrylate, benzylbenzyl (meth)acrylate, and the like; (meth)acrylic acid alkoxyalkyl esters such as 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, 4-ethoxybutyl (meth)acrylate, and the like; vinyl esters such as vinyl acetate, vinyl propionate, and the like; aromatic vinyl compounds such as styrene, vinyltoluene, and the like; olefins or dienes such as ethylene, butadiene, isoprene, isobutylene, and the like; vinyl ethers such as vinyl alkyl ether, and the like; vinyl chloride; and the like.

[0076] As the co-polymerizable monomer, a multi-functional monomer can also be used. The multi-functional 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 can be used without impairing the effects of the present application. As such an ethylenically unsaturated group, for example, a radical polymerizable functional group such as a vinyl group, a propenyl group, an isopropenyl group, a vinyl ether group (vinyloxy group), an allyl ether group (allyloxy group), and the like can be exemplified. As the multi-functional monomer, for example, 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, and the like can be exemplified. Such a multi-functional monomer can be only one or two or more.

[0077] From the aspect of more expressing the effects of the present application, the content of the alkyl (meth)acrylate having an alkyl group having a carbon number of 4 to 12 (a component) is preferably 30% by mass or more, more preferably 35% by mass to 99% by mass, further preferably 40% by mass to 98% by mass, and particularly preferably 50% by mass to 95% by mass, relative to the total amount of the monomer components constituting the acrylic polymer (100% by mass).

[0078] From the aspect of more expressing the effects of the present application, the content of at least one selected from the group consisting of a (meth)acrylate having an OH group and a (meth)acrylic acid (b component) is preferably 1% by mass or more, more preferably 1% by mass to 30% by mass, further preferably 2% by mass to 20% by mass, and particularly preferably 3% by mass to 10% by mass, relative to the total amount of the monomer components constituting the acrylic polymer (100% by mass).

[0079] The composition (M) can contain any appropriate other component within a range not impairing the effects of the present application. As such an other component, for example, a polymerization initiator, a chain transfer agent, a solvent, and the like can be exemplified. The content of these other components can be any appropriate content within a range not impairing the effects of the present application.

[0080] The polymerization initiator can be a thermal polymerization initiator, a photopolymerization initiator (a photoinitiator), or the like according to the type of the polymerization reaction. The polymerization initiator can be only one or two or more.

[0081] A thermal polymerization initiator can be preferably used when the acrylic polymer is obtained by solution polymerization. As such a thermal polymerization initiator, for example, azo-based initiators such as 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 4,4'-azobis-4-cyanovaleric acid, azobis isovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazoline-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.), and the like; persulfates such as potassium persulfate, ammonium persulfate, and the like; peroxide-based initiators such as di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyneopentanoate, tert-butyl peroxyneopentanoate, dilauryl peroxydicarbonate, di-n-octyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, dibenzoyl peroxide, tert-butyl peroxyisobutyrate, 1,1-di(tert-hexylperoxy)cyclohexane, tert-butyl hydroperoxide, hydrogen peroxide, and the like; combinations of a persulfate and sodium bisulfite, combinations of a peroxide and sodium ascorbate, and the like, which are redox initiators in which a peroxide is combined with a reducing agent; substituted ethane-based initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0082] A photopolymerization initiator is preferably used when the acrylic polymer is obtained by polymerization with active energy rays. As the photopolymerization initiator, for example, benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-keto alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzil-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators can be listed.

[0083] As the benzoin ether-based photopolymerization initiator, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-ketone, benzyl ether methyl ether, and the like can be exemplified. As the acetophenone-based photopolymerization initiator, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, 4-(tert-butyl)dichloroacetophenone can be exemplified. As the α-keto alcohol-based photopolymerization initiator, for example, 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropane-1-ketone can be exemplified. As the aromatic sulfonyl chloride-based photopolymerization initiator, for example, 2-naphthalenesulfonyl chloride can be exemplified. As the photoactive oxime-based photopolymerization initiator, for example, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime can be exemplified. As the benzoin-based photopolymerization initiator, for example, benzoin can be exemplified. As the benzil-based photopolymerization initiator, for example, benzil can be exemplified. As the benzophenone-based photopolymerization initiator, for example, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone can be exemplified. As the ketal-based photopolymerization initiator, for example, benzyl dimethyl ketal can be exemplified. As the thioxanthone-based photopolymerization initiator, for example, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone can be exemplified.

[0084] The amount of use of the polymerization initiator can be set to any appropriate amount of use within a range that does not impair the effects of the present application.

[0085] The acrylic adhesive composition can contain a crosslinking agent. The cohesion of the acrylic adhesive can be improved by using a crosslinking agent, and the effects of the present application can be more exhibited. The crosslinking agent can be only one or two or more.

[0086] As the crosslinking agent, for example, 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, peroxides, and the like can be exemplified, and at least one (c component) selected from the group consisting of isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and peroxides is preferred from the aspect that the effects of the present application can be more exhibited.

[0087] The isocyanate-based crosslinking agent can use a compound having two or more isocyanate groups (including an isocyanate regenerable polar group temporarily protected by a blocking agent or polymerization, etc.) in one molecule. As the isocyanate-based crosslinking agent, for example, aromatic isocyanates such as toluene diisocyanate, xylene diisocyanate, etc.; alicyclic isocyanates such as isophorone diisocyanate, etc.; aliphatic isocyanates such as hexamethylene diisocyanate, etc. can be exemplified.

[0088] As the isocyanate-based crosslinking agent, for example, lower aliphatic polyisocyanates such as butylene diisocyanate, hexamethylene diisocyanate, etc.; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, etc.; aromatic diisocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, etc.; isocyanate adducts such as trimethylolpropane / toluene diisocyanate trimer adduct (for example, manufactured by Tosoh Corporation, trade name: CORONATE L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (for example, manufactured by Tosoh Corporation, trade name: CORONATE HL), isocyanurate of hexamethylene diisocyanate (for example, manufactured by Tosoh Corporation, trade name: CORONATE HX), etc.; trimethylolpropane adducts of xylylene diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D110N), trimethylolpropane adducts of xylylene diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D120N), trimethylolpropane adducts of isophorone diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D140N), trimethylolpropane adducts of hexamethylene diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D160N), trimethylolpropane adducts of toluene diisocyanate (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D101E); polyether polyisocyanates, polyester polyisocyanates, and adducts of these compounds with various polyols; polyisocyanates polyfunctionalized by isocyanurate bonds, biuret bonds, allophanate bonds, etc. can be exemplified. Among these, from the viewpoint of being able to balance deformability and cohesive force well, aromatic isocyanates, alicyclic isocyanates are preferable.

[0089] As the epoxy-based crosslinking agent, a multifunctional epoxy compound having two or more epoxy groups in one molecule can be used. As the epoxy-based crosslinking agent, for example, N,N,N',N'-tetraglycidyl-m-phenylenediamine, diglycidyl aniline, 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, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, trisglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol S diglycidyl ether, and an epoxy-based resin having two or more epoxy groups in one molecule can be listed. As the commercially available epoxy-based crosslinking agent, for example, "TETRAD C" and "TETRAD X" manufactured by Mitsubishi Gas Chemical Co., Ltd. can be listed.

[0090] As the peroxide, for example, dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)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-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, dilauryl peroxide, di-n-octyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, t-butyl peroxy-2-ethylhexyl carbonate, t-amyl peroxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, t-butyl peroxy-2-hexanoate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate can be listed. As the commercially available peroxide, for example, "NYPER BMT" series and "NYPER BW" series manufactured by NOF Corporation can be listed.

[0091] The content of the crosslinking agent in the acrylic adhesive composition can employ any appropriate content within a range not impairing the effects of the present application. As such a content, for example, from the aspect of more being able to exhibit the effects of the present application, it is preferably 0.01 part by weight or more and 20 parts by weight or less, more preferably 0.01 part by weight or more and 18 parts by weight or less, further preferably 0.01 part by weight or more and 15 parts by weight or less, particularly preferably 0.05 part by weight or more and 10 parts by weight or less, with respect to 100 parts by weight of the solid content of the acrylic polymer.

[0092] The acrylic adhesive composition can contain any appropriate other component within a range not impairing the effects of the present application. As such an other component, for example, there can be mentioned: a polymer component other than the acrylic polymer, a crosslinking accelerator, a crosslinking catalyst, a silane coupling agent, a tackifying resin (a rosin derivative, a polyterpene resin, a petroleum resin, an oil-soluble phenol, etc.), an anti-aging agent, an inorganic filler, an organic filler, a metal powder, a coloring agent (a pigment, a dye, etc.), a foil, an ultraviolet absorber, an antioxidant, a light stabilizer, a nucleating agent, a chain transfer agent, a plasticizer, a softening agent, a surfactant, an antistatic agent, a conductive agent, a stabilizer, a surface lubricant, a leveling agent, an anticorrosive agent, a heat-resistant stabilizer, a polymerization inhibitor, a lubricant, a solvent, a catalyst, and the like.

[0093] 2. Optical devices and electronic devices

[0094] For the surface protective film of the embodiment of the present application, in the manufacturing process of the optical device or the electronic device, when processing, assembling, inspecting, transporting, and the like are performed, in order to prevent damage to the surface of the optical member or the electronic member, it is preferably used for surface protection of the optical member or the electronic member. The optical device of the embodiment of the present application includes the surface protective film of the embodiment of the present application. The electronic device of the embodiment of the present application includes the surface protective film of the embodiment of the present application.

[0095] [Examples]

[0096] Hereinafter, the present application will be specifically described by way of examples, but the present application is not limited by these examples at all. Note that the test and evaluation methods in the examples and the like are as described below. Note that in the case where "parts" is described, it means "parts by weight" unless otherwise specified, and in the case where "%" is described, it means "wt%" unless otherwise specified.

[0097] Measurement of b * value of the surface protective film as a whole

[0098] The b value was measured using a high-speed integrating sphere type transmittance meter (manufactured by Murakami Color Research Laboratory Co., Ltd., model "DOT-3C") with light incident from the substrate layer side of the surface protective film obtained in each of the examples and comparative examples. * The b value is a CIELab value. * The b value is a CIELab value.

[0099] O: The b value is 0.70 or greater. *

[0100] X: The b value is less than 0.70. *

[0101] <Measurement of the transmittance of light having a wavelength of 550 nm for the surface protective film as a whole>

[0102] The transmittance of light having a wavelength of 550 nm was measured using a high-speed integrating sphere type transmittance meter (manufactured by Murakami Color Research Laboratory Co., Ltd., model "DOT-3C") with light incident from the substrate layer side of the surface protective film obtained in each of the examples and comparative examples.

[0103] O: The transmittance of light having a wavelength of 550 nm is 85% or greater.

[0104] X: The transmittance of light having a wavelength of 550 nm is less than 85%.

[0105] <Measurement of the b value for the laminate obtained by removing the release liner from the surface protective film> *

[0106] The b value was measured using a high-speed integrating sphere type transmittance meter (manufactured by Murakami Color Research Laboratory Co., Ltd., model "DOT-3C") with light incident from the substrate layer side of the surface protective film obtained in each of the examples and comparative examples. * The b value is a CIELab value. * The b value is a CIELab value.

[0107] O: The b value is less than 0.50. *

[0108] X: The b value is 0.50 or greater. *

[0109] <Measurement of the b value for the laminate obtained by stacking 15 surface protective films> *

[0110] The b value was measured using a high-speed integrating sphere type transmittance meter (manufactured by Murakami Color Research Laboratory Co., Ltd., model "DOT-3C") with light incident from the substrate layer side of the surface protective film obtained in each of the examples and comparative examples. * The b value is a CIELab value.​​​​​​* The value refers to the CIELab value.

[0111] O: b * The value is 7.00 or greater.

[0112] X: b * The value is less than 7.00.

[0113] <Measurement of Reflectance of a Laminated Body in Which 15 Surface Protective Films are Laminated>

[0114] A laminated body in which 15 surface protective films obtained in the examples and comparative examples were laminated was assembled to a spectrophotometer (manufactured by Shimadzu Corporation, trade name "UV-VIS Ultraviolet Visible Spectrophotometer SolidSpec 3700"), and the 5° reflectance in the wavelength region of 300 nm to 800 nm was measured with the incident light being perpendicularly incident to the substrate layer side of the surface protective film.

[0115] O: The reflectance is less than 40.0%.

[0116] X: The reflectance is 40.0% or greater.

[0117] <Evaluation of Recognizability of Surface Protective Film in Storage State>

[0118] Laminated bodies in which 15 surface protective films obtained in the examples and comparative examples were laminated and laminated bodies in which 15 PET films (manufactured by TORAY Corporation, trade name "lumirror S10", thickness = 25 μm) were laminated were arranged, and it was confirmed whether or not the difference between the laminated body of the surface protective film and the laminated body of the PET film could be recognized by visual observation from the planar direction of the release liner side, and the evaluation was performed according to the following criteria.

[0119] O: The difference between the laminated body of the surface protective film obtained in the examples and comparative examples and the laminated body of the PET film could be recognized. That is, the surface protective film of O could prevent the mistake of taking out before peeling off the release liner, and could prevent forgetting to peel off the release liner at the time of use.

[0120] X: The difference between the laminated body of the surface protective film obtained in the examples and comparative examples and the laminated body of the PET film could not be recognized.

[0121] <Evaluation of Optical Checkability>

[0122] A circle of 3 cm in diameter in which the HEX color code "#FDFAD7" was displayed on a display with the transparency adjusted to 70% was prepared, and a laminated body in which 15 surface protective films obtained in the examples and comparative examples were laminated was placed thereon with the release liner side being the display side, and the visual confirmability of the circle was evaluated by visual observation according to the following criteria. Note that HEX is an abbreviation of "Hexadecimal", and is a color code expressed in hexadecimal notation.

[0123] O: The circle can be visually confirmed.

[0124] X: The circle cannot be visually confirmed.

[0125] [Production Example 1] Preparation of Acrylic Adhesive Composition (1)

[0126] Into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, 96 parts by weight of acrylic acid 2-ethylhexyl ester (2EHA) and 4 parts by weight of acrylic acid 2-hydroxyethyl ester (HEA) as monomers, 0.2 parts by weight of 2,2'-azobis- isobutyronitrile (AIBN) as a polymerization initiator, and 150 parts by weight of ethyl acetate were charged. While slowly stirring, nitrogen gas was introduced, and the liquid temperature in the flask was maintained at about 65°C to perform a polymerization reaction for 6 hours, thereby obtaining a solution of acrylic polymer A having a weight average molecular weight of 540,000.

[0127] Next, 4 parts by weight of an isocyanate crosslinking agent (trade name "CORONATE HX", manufactured by Tosoh Corporation) and 0.015 parts by weight of EMBILIZER OL-1 (manufactured by Tokyo Fine Chemical Corporation) as a catalyst were added to 100 parts by weight of the acrylic polymer A (solid content) to prepare an acrylic adhesive composition (1) having a solid content of 30% by weight.

[0128] [Production Example 2] Preparation of Thermosetting Silicone Release Treatment Agent Solution

[0129] A silicone release agent (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847H) and a silicone curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T) were added in amounts of 100 parts by weight and 3.3 parts by weight, respectively, and diluted with a solvent formed by toluene, n-hexane, and methyl ethyl ketone in a weight ratio of 1:2:1 to a solid content of 0.3% by weight, thereby obtaining a thermosetting silicone release treatment agent solution.

[0130] [Example 1]

[0131] (Production of Release Liner (1))

[0132] To 100 mL of hot water at 90°C, 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.) were added, and mixed well to prepare a dye.

[0133] In addition, add 2g of dark color accelerator (manufactured by KATSURAYA FINEGOODS, trade name "Dark Color Accelerator") to 1900mL of hot water at 90℃, mix thoroughly, and prepare an accelerator solution.

[0134] Add the dye to the above-mentioned promoting solution and mix thoroughly to prepare a dyeing agent with a concentration of 2 g / L.

[0135] By keeping the obtained dye at 90°C, a 25μm thick PET film (manufactured by TORAY, trade name "lumirror S10") is immersed for 10 seconds to produce a dyed PET film.

[0136] Using a Mayer rod, the thermosetting silicone-based release agent solution obtained in Manufacturing Example 2 was applied to the dyed PET film, and dried by heating at 130°C for 30 seconds to produce a release liner (1) with a silicone-based release layer of 0.1 μm thickness.

[0137] (Manufacturing of surface protective film (1))

[0138] The acrylic adhesive composition (1) obtained in Manufacturing Example 1 was coated onto the side opposite to the corona-treated side of a 38 μm thick biaxially stretched polyester film (Mitsubishi Chemical, trade name "Diafoil T100C38"), and heated at 130°C for 30 seconds to form an adhesive layer with a thickness of 21 μm. Then, the silicone release layer side of the release liner (1) prepared above was adhered to obtain a surface protective film (1).

[0139] The results are shown in Table 1.

[0140] [Example 2]

[0141] (Making of peeling lining (2))

[0142] Add 2g each of POLYESTER DYE YELLOW (manufactured by KATSURAYA FINEGOODS Co., Ltd.) and POLYESTER DYE ORANGE (manufactured by KATSURAYA FINEGOODS Co., Ltd.) to 100mL of hot water at 90℃, mix thoroughly, and prepare the dye.

[0143] In addition, add 4g of dark color accelerator (manufactured by KATSURAYA FINEGOODS, trade name "Dark Color Accelerator") to 1900mL of hot water at 90℃, mix thoroughly, and prepare an accelerator solution.

[0144] Add the dye to the above-mentioned promoting solution and mix thoroughly to prepare a dyeing agent with a concentration of 4 g / L.

[0145] The obtained dyeing agent was kept at 90°C, and a PET film (TORAY Co., Ltd., trade name "lumirror S10") having a thickness of 25 μm was immersed for 10 seconds to produce a dyed PET film.

[0146] The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Meyer bar, 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.

[0147] (Production of the surface protective film (2))

[0148] The acrylic-based adhesive composition (1) obtained in Production Example 1 was applied to the surface opposite to the corona-treated surface of a biaxially-stretched polyester film (Mitsubishi Chemical, trade name "Diafoil T100C38") having a thickness of 38 μm, and heated at 130°C for 30 seconds to form an adhesive layer having a thickness of 21 μm. Subsequently, the silicone-based release layer side of the release liner (2) produced in the above was attached to obtain a surface protective film (2).

[0149] The results are shown in Table 1.

[0150] [Example 3]

[0151] (Production of the release liner (3))

[0152] To 100 mL of hot water at 90°C was added 4 g of POLYESTER DYE YELLOW (KATSURAYA FINE GOODS Co., Ltd.), and mixed well to prepare a dye.

[0153] To 1900 mL of hot water at 90°C was added 4 g of a dark color accelerator (KATSURAYA FINE GOODS, trade name "Dark Color Accelerator"), and mixed well to prepare an accelerator solution.

[0154] To the above accelerator solution was added the above dye, and mixed well to prepare a dyeing agent having a concentration of 4 g / L.

[0155] The obtained dyeing agent was kept at 90°C, and a PET film (TORAY Co., Ltd., trade name "lumirror S10") having a thickness of 25 μm was immersed for 10 seconds to produce a dyed PET film.

[0156] The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Meyer bar, 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.

[0157] (Manufacture of surface protective film (3))

[0158] The acrylic adhesive composition (1) obtained in Production Example 1 was coated on the surface opposite to the corona-treated surface of a biaxially-stretched polyester film (Mitsubishi Chemical, trade name "Diafoil T100C38") having a thickness of 38 μm, and heated at 130°C for 30 seconds to form an adhesive layer having a thickness of 21 μm. Next, the silicone-based release layer side of the release liner (3) produced above was attached to obtain a surface protective film (3).

[0159] The results are shown in Table 1.

[0160] [Example 4]

[0161] (Production of release liner (4))

[0162] To 100 mL of hot water at 90°C, 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.) were added and mixed well to prepare a dye.

[0163] To 1900 mL of hot water at 90°C, 8 g of a dark color accelerator (trade name "Dark Color Accelerator", manufactured by KATSURAYA FINE GOODS Co., Ltd.) was added and mixed well to prepare an accelerator solution.

[0164] To the above accelerator solution, the above dye was added and mixed well to prepare a dyeing agent having a concentration of 8 g / L.

[0165] The obtained dyeing agent was kept at 90°C, and a PET film (TORAY Co., Ltd., trade name "lumirror S10") having a thickness of 25 μm was immersed in the dyeing agent for 60 seconds to produce a dyed PET film.

[0166] The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was coated on the obtained dyed PET film using a Meyer rod, and dried at 130°C for 30 seconds to produce a release liner (4) having a silicone-based release layer having a thickness of 0.1 μm.

[0167] (Production of surface protective film (4))

[0168] The acrylic adhesive composition (1) obtained in Production Example 1 was coated on the surface of a biaxially-stretched polyester film (Mitsubishi Chemical, trade name "Diafoil T100C38") having a thickness of 38 μm, opposite to the surface subjected to the corona treatment, and heated at 130°C for 30 seconds to form an adhesive layer having a thickness of 21 μm. Subsequently, the silicone-based release layer side of the release liner (4) produced in the above was attached to obtain a surface protective film (4).

[0169] The results are shown in Table 1.

[0170] [Comparative Example 1]

[0171] (Production of Release Liner (C1))

[0172] The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was coated on a polyester film (Mitsubishi Chemical, trade name "Diafoil T100C25") having a thickness of 25 μm using a Meyer bar, and dried at 130°C for 30 seconds to produce a release liner (C1) having a silicone-based release layer with a thickness of 0.1 μm.

[0173] (Production of Surface Protective Film (C1))

[0174] The acrylic adhesive composition (1) obtained in Production Example 1 was coated on the surface of a biaxially-stretched polyester film (Mitsubishi Chemical, trade name "Diafoil T100C38") having a thickness of 38 μm, opposite to the surface subjected to the corona treatment, and heated at 130°C for 30 seconds to form an adhesive layer having a thickness of 21 μm. Subsequently, the silicone-based release layer side of the release liner (C1) produced in the above was attached to obtain a surface protective film (C1).

[0175] The results are shown in Table 1.

[0176] [Comparative Example 2]

[0177] (Production of Release Liner (C2))

[0178] The thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was coated on a polyester film (Mitsubishi Chemical, trade name "Diafoil T100C50") having a thickness of 50 μm using a Meyer bar, and dried at 130°C for 30 seconds to produce a release liner (C2) having a silicone-based release layer with a thickness of 0.1 μm.

[0179] (Production of Surface Protective Film (C2))

[0180] The acrylic adhesive composition (1) obtained in Production Example 1 was applied to the surface opposite to the corona-treated surface of a biaxially-stretched polyester film (Mitsubishi Chemical, trade name "Diafoil T100C38") having a thickness of 38 μm, and heated at 130°C for 30 seconds to form an adhesive layer having a thickness of 21 μm. Subsequently, the silicone release layer side of the release liner (C2) produced in the above was attached to obtain a surface protective film (C2).

[0181] The results are shown in Table 1.

[0182] [Comparative Example 3]

[0183] (Production of Release Liner (C3))

[0184] To 100 mL of hot water at 90°C was added 4 g of POLYESTER DYE BROWN (manufactured by KATSURAYA FINE GOODS Co., Ltd.), and mixed well to prepare a dye.

[0185] To 1900 mL of hot water at 90°C was further added 4 g of a dark color accelerator (manufactured by KATSURAYA FINE GOODS Co., Ltd., trade name "Dark Color Accelerator"), and mixed well to prepare an accelerator solution.

[0186] To the above accelerator solution was added the above dye, and mixed well to prepare a dyeing agent having a concentration of 4 g / L.

[0187] The obtained dyeing agent was kept at 90°C, and a PET film (TORAY Co., Ltd., trade name "lumirror S10") having a thickness of 25 μm was immersed therein for 2 minutes to produce a dyed PET film.

[0188] The thermosetting silicone release treatment agent solution obtained in Production Example 2 was applied to the obtained dyed PET film using a Meyer rod, and dried at 130°C for 30 seconds to produce a release liner (C3) having a silicone release layer having a thickness of 0.1 μm.

[0189] (Production of Surface Protective Film (C3))

[0190] The acrylic adhesive composition (1) obtained in Production Example 1 was applied to the surface opposite to the corona-treated surface of a biaxially-stretched polyester film (Mitsubishi Chemical, trade name "Diafoil T100C38") having a thickness of 38 μm, and heated at 130°C for 30 seconds to form an adhesive layer having a thickness of 21 μm. Subsequently, the silicone release layer side of the release liner (C3) produced in the above was attached to obtain a surface protective film (C3).

[0191] The results are shown in Table 1.

[0192] [Comparative Example 4]

[0193] (Production of release liner (C4))

[0194] A thermosetting silicone-based release treatment agent solution obtained in Production Example 2 was coated on a polyester film (Mitsubishi Chemical, trade name "Diafoil T100C25") having a thickness of 25 μm using a Meyer bar, and dried at 130°C for 30 seconds to produce a release liner (C4) having a silicone-based release layer with a thickness of 0.1 μm.

[0195] (Production of polyethylene film)

[0196] A polyethylene resin (Tosoh Corporation, trade name "Nipolon Hard 4000", high-density polyethylene produced by a low-pressure slurry method) was extruded in a T-die molding machine to produce a polyethylene film having a thickness of 100 μm. The obtained polyethylene film was subjected to corona treatment on one side thereof by a corona treatment device (Kaneka Electric Machine Co., Ltd., table-type treatment station, high-frequency power supply device AGI-020SF) at an output of 0.3 kW and a treatment speed of 2 m / min.

[0197] (Production of surface protective film (C4))

[0198] The acrylic-based adhesive composition (1) obtained in Production Example 1 was coated on the silicone-based release layer side of the release liner (C4) produced above, and heated at 130°C for 30 seconds to form an adhesive layer having a thickness of 21 μm. Subsequently, the adhesive layer was attached to the corona-treated surface of the polyethylene film produced above to obtain a surface protective film (C4).

[0199] The results are shown in Table 1.

[0200] [Table 1]

[0201]

[0202] Industrial applicability

[0203] The surface protective film of the present application can be used, for example, for any appropriate purpose such as preventing surface damage of optical members, electronic members, etc. during processing, assembly, inspection, transportation, etc. in the manufacturing process of optical devices, electronic devices, etc.

Claims

1. A surface protective film comprising, in sequence, a substrate layer, an adhesive layer, and a release liner. The overall b of the surface protective film * A value above 0.70 The overall transmittance of the surface protective film at a wavelength of 550nm is over 85%. b, the laminate obtained by removing the peeling liner from the surface protective film * The value is less than 0.

50.

2. The surface protective film according to claim 1, wherein, b is a laminate formed by stacking 15 of the aforementioned surface protective films. * The value is 7.00 or higher.

3. The surface protective film according to claim 1, wherein, The reflectivity of the laminate formed by stacking 15 of the aforementioned surface protective films is less than 40.0%.

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

5. The surface protective film according to claim 1, wherein, The thickness of the stripping liner is 1 μm to 300 μm.

6. An optical device comprising a surface protective film as claimed in any one of claims 1 to 5.

7. An electronic device comprising a surface protective film as claimed in any one of claims 1 to 5.

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