Surface protection film

Abstract

To provide a surface protective film capable of exhibiting light peelability and suppressing the occurrence of black spots, and to provide an optical member and an electronic member each having the surface protective film attached thereto.SOLUTION: A surface protective film according to an embodiment of the present invention includes an adhesive layer, wherein the adhesive layer is composed of a urethane-based adhesive formed from a urethane-based adhesive composition, and the urethane-based adhesive composition contains a base polymer and a fluorine-based compound. The base polymer includes a urethane prepolymer, and the percentage of hydroxyl groups contained in the urethane-based adhesive composition is less than 30 mmol with respect to 100 g of the base polymer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a surface protection film. [Background technology]

[0002] Surface protection films are attached to optical and electronic components to prevent their surfaces from being scratched during processing, assembly, inspection, transportation, etc. Such surface protection films are peeled off from the optical and electronic components when surface protection is no longer necessary (Patent Document 1).

[0003] When attempting to peel off such a surface protection film from an optical or electronic component to which such a surface protection film is attached, it is important that the surface protection film can be peeled off smoothly only at the interface between the surface protection film and the optical or electronic component.

[0004] A pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive is known as a pressure-sensitive adhesive layer provided in a surface protection film. Two types of manufacturing methods for urethane-based pressure-sensitive adhesives are known: a one-shot method in which a urethane pressure-sensitive adhesive is manufactured by directly reacting a polyol with a multifunctional isocyanate without using a urethane prepolymer, and a prepolymer method in which a urethane pressure-sensitive adhesive is manufactured by reacting a urethane prepolymer with a multifunctional isocyanate.

[0005] In a surface protection film having a pressure-sensitive adhesive layer composed of a urethane-based pressure-sensitive adhesive, a technique is known in which a fluorine-based compound is contained in the pressure-sensitive adhesive composition that forms the urethane-based pressure-sensitive adhesive in order to exhibit easy peelability, etc. (Patent Document 2).

[0006] However, when a conventional surface protection film having a pressure-sensitive adhesive layer composed of a urethane-based pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition containing a fluorine-based compound was observed, the occurrence of black spots presumably caused by adhesive depressions was observed. The occurrence of such black spots frequently may not only lead to a deterioration in the quality of the surface protection film, but may also reduce the inspectability of the surface protection film, for example, in the case of a surface protection film to be attached to an optical component or an electronic component. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-17109 [Patent Document 2] Patent No. 6896927 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a surface protection film that exhibits easy releasability and can suppress the occurrence of black spots, and to provide optical and electronic components to which such a surface protection film is attached. [Means for solving the problem]

[0009] The surface protective film according to an embodiment of the present invention comprises: A surface protection film including a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is composed of a urethane-based pressure-sensitive adhesive formed from a urethane-based pressure-sensitive adhesive composition, The urethane-based pressure-sensitive adhesive composition contains a base polymer and a fluorine-based compound, the base polymer comprises a urethane prepolymer; The proportion of hydroxyl groups contained in the urethane-based pressure-sensitive adhesive composition is less than 30 mmol per 100 g of the base polymer.

[0010] In one embodiment, the base polymer comprises a polyoxyalkylene structure represented by general formula (1). [ka] (In general formula (1), R 1 represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms. 1 may be the same as or different from each other. n represents an integer of 1 to 4. m represents an integer of 1 to 200.

[0011] In one embodiment, the urethane prepolymer contains a polyoxyalkylene structure represented by the general formula (1).

[0012] In one embodiment, the base polymer comprises a polyol, and the polyol is not a urethane prepolymer.

[0013] In one embodiment, the polyol contains a polyoxyalkylene structure represented by general formula (1). [ka] (In general formula (1), R 1 represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms. 1 may be the same as or different from each other. n represents an integer of 1 to 4. m represents an integer of 1 to 200.

[0014] In one embodiment, the urethane-based pressure-sensitive adhesive composition contains the urethane prepolymer and the polyol in a weight ratio of urethane prepolymer:polyol of 70:30 to 100:0.

[0015] In one embodiment, the pressure-sensitive adhesive layer has a haze of 3.5% or less.

[0016] In one embodiment, the fluorine-based compound has a surface tension of 23 mN / m or more when it is dissolved in a 0.1% propylene glycol monomethyl ether solution.

[0017] In one embodiment, the urethane-based pressure-sensitive adhesive composition comprises 0.05 parts by weight or more of an ionic compound relative to 100 parts by weight of the base polymer.

[0018] The optical member according to the embodiment of the present invention has a surface protection film according to the embodiment of the present invention attached thereto.

[0019] The electronic component according to the embodiment of the present invention has a surface protection film according to the embodiment of the present invention attached thereto. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a surface protection film that exhibits easy releasability and can suppress the occurrence of black spots, and also to provide optical members and electronic members to which such a surface protection film is attached. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic cross-sectional view of a surface protection film according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] <<<<1. Surface protection film>>>> The surface protection film according to the embodiment of the present invention includes a pressure-sensitive adhesive layer. The surface protection film according to the embodiment of the present invention preferably includes a substrate layer and a pressure-sensitive adhesive layer.

[0023] The substrate layer may be only one layer or may be two or more layers.

[0024] The pressure-sensitive adhesive layer may be a single layer or two or more layers.

[0025] Any appropriate release liner may be attached to the adhesive surface (sometimes referred to as glue surface) of the pressure-sensitive adhesive layer, as long as the effects of the present invention are not impaired.

[0026] Examples of release liners include release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is silicone-treated, and release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin.

[0027] Any suitable plastic film can be used as the plastic film substrate of the release liner as long as the effects of the present invention are not impaired. Examples of such plastic films include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene-vinyl acetate copolymer film.

[0028] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, even more preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0029] When the surface protection film according to an embodiment of the present invention comprises a substrate layer and a pressure-sensitive adhesive layer, the surface of the substrate layer opposite the pressure-sensitive adhesive layer may be subjected to a release treatment by adding, for example, a fatty acid amide, polyethyleneimine, a long-chain alkyl additive, or the like to the substrate layer, or a coating layer made of any suitable release agent, such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent, may be provided, for example, in order to form a roll that is easy to unwind.

[0030] The surface protection film according to the embodiment of the present invention may have any other appropriate layer within the scope that does not impair the effects of the present invention.

[0031] Fig. 1 is a schematic cross-sectional view of a surface protection film according to a preferred embodiment of the present invention. As shown in Fig. 1, a surface protection film 10 according to a preferred embodiment of the present invention includes a base layer 1 and a pressure-sensitive adhesive layer 2, and the base layer 1 and the pressure-sensitive adhesive layer 2 are directly laminated together.

[0032] The thickness of the surface protection film according to the embodiment of the present invention can be set to any appropriate thickness depending on the application, and is typically preferably 10 μm to 300 μm, more preferably 15 μm to 250 μm, even more preferably 20 μm to 200 μm, and particularly preferably 25 μm to 170 μm.

[0033] The surface protection film according to the embodiment of the present invention preferably exhibits easy releasability. The surface protection film according to the present invention exhibits a peel strength of preferably 0.5 gf / 25 mm to 5.0 gf / 25 mm, more preferably 0.5 gf / 25 mm to 4.0 gf / 25 mm, even more preferably 0.5 gf / 25 mm to 3.0 gf / 25 mm, particularly preferably 0.5 gf / 25 mm to 2.5 gf / 25 mm, and most preferably 0.5 gf / 25 mm to 2.0 gf / 25 mm, when the pressure-sensitive adhesive layer contained therein is adhered to a glass plate and, after 30 minutes at 23°C, peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min. If the peel strength is within the above range, the surface protection film according to the embodiment of the present invention can exhibit excellent easy releasability. Details of the method for measuring the peel strength will be described later.

[0034] The surface protection film according to the embodiment of the present invention can preferably achieve low haze. The surface protection film of the present invention includes a pressure-sensitive adhesive layer having a haze of preferably 4.0% or less, more preferably 3.0% or less, even more preferably 2.0% or less, particularly preferably 1.5% or less, and most preferably 1.0% or less. If the haze is within the above range, the surface protection film according to the embodiment of the present invention can achieve excellent low haze and, for example, can exhibit excellent inspectability. The method for measuring the haze will be described in detail below.

[0035] The surface protection film according to an embodiment of the present invention preferably exhibits a peeling electrification voltage of 15 kV or less, more preferably 10 kV or less, even more preferably 5 kV or less, particularly preferably 2 kV or less, and most preferably 1 kV or less when the pressure-sensitive adhesive layer contained therein is attached to a glass plate, left for one day in an environment of 23°C and 50% RH, and then peeled from the glass plate at a peeling angle of 150° and a peeling speed of 30 m / min. If the peeling electrification voltage is within the above range, the surface protection film according to an embodiment of the present invention can effectively prevent charging during peeling. Details of the method for measuring the peeling electrification voltage will be described later.

[0036] <<1-1. Adhesive layer>> The pressure-sensitive adhesive layer is composed of a urethane-based pressure-sensitive adhesive. The urethane-based pressure-sensitive adhesive is formed from a urethane-based pressure-sensitive adhesive composition. That is, the urethane-based pressure-sensitive adhesive formed from the urethane-based pressure-sensitive adhesive composition forms a layer shape, thereby becoming the pressure-sensitive adhesive layer.

[0037] The thickness of the pressure-sensitive adhesive layer can be set to any appropriate thickness depending on the application, and is typically preferably 1 μm to 150 μm, more preferably 5 μm to 130 μm, even more preferably 10 μm to 110 μm, and particularly preferably 20 μm to 100 μm.

[0038] The urethane-based pressure-sensitive adhesive composition contains a base polymer and a fluorine-based compound. The base polymer may be of only one type or may contain two or more types. The fluorine-based compound may be of only one type or may contain two or more types.

[0039] The base polymer includes a urethane prepolymer, the details of which will be described later.

[0040] The base polymer may contain a polyol. Details of the polyol will be described later. As will be described later, the polyol in the present invention is not a urethane prepolymer.

[0041] The base polymer embodiment of the present invention preferably comprises: (A) an embodiment comprising a urethane prepolymer and no polyol; or (B) an embodiment comprising both a urethane prepolymer and a polyol; is.

[0042] A more preferred embodiment of the base polymer in the present invention is (a) an embodiment comprising a urethane prepolymer; or (b) an embodiment consisting of a urethane prepolymer and a polyol; is.

[0043] The content of the base polymer in the urethane-based pressure-sensitive adhesive composition is preferably 50% by weight to 99.99% by weight, more preferably 70% by weight to 99.99% by weight, even more preferably 90% by weight to 99.99% by weight, and particularly preferably 95% by weight to 99.99% by weight, in order to further exhibit the effects of the present invention. By adjusting the content of the base polymer in the urethane-based pressure-sensitive adhesive composition within the above range, the surface protection film of the present invention can further exhibit the effects of the present invention.

[0044] The urethane-based pressure-sensitive adhesive composition contains less than 30 mmol of hydroxyl groups per 100 g of base polymer, preferably 5 mmol to 28 mmol, more preferably 5 mmol to 25 mmol, even more preferably 5 mmol to 22 mmol, and particularly preferably 5 mmol to 20 mmol. By ensuring that the proportion of hydroxyl groups contained in the urethane-based pressure-sensitive adhesive composition per 100 g of base polymer is within the above range, the effects of the present invention can be achieved.

[0045] In completing the present invention, the present inventors conducted extensive research into the suppression of black spot formation, which was a problem. As a result, they concluded that black spot formation might be caused by stable micelles formed around air bubbles generated during the PSA formation process, due to the fluorine-based compound acting as a surfactant, and that these bubbles ultimately cause adhesive depressions when the PSA layer is formed. Therefore, the present inventors suspected that the suppression of micelle formation could suppress the occurrence of black spot formation. As a result of further research, they focused on the compatibility of the base polymer (typically a urethane prepolymer and an optional polyol) and the fluorine-based compound in the urethane PSA composition. Further research into adjusting the compatibility between the base polymer and the fluorine-based compound led to the discovery, as described above, that the occurrence of black spot formation can be effectively suppressed by adjusting the ratio of hydroxyl groups contained in the urethane PSA composition to 100 g of base polymer within the above range.

[0046] A urethane-based pressure-sensitive adhesive can be defined as something formed from a urethane-based pressure-sensitive adhesive composition. This is because a urethane-based pressure-sensitive adhesive becomes a urethane-based pressure-sensitive adhesive when the urethane-based pressure-sensitive adhesive composition undergoes a crosslinking reaction due to heating or ultraviolet irradiation, etc., and therefore it is impossible and impractical to directly identify a urethane-based pressure-sensitive adhesive by its structure ("impossible / impractical circumstances"). Therefore, the definition of "something formed from a urethane-based pressure-sensitive adhesive composition" appropriately identifies a urethane-based pressure-sensitive adhesive as a "product."

[0047] As a method for forming a urethane-based pressure-sensitive adhesive from a urethane-based pressure-sensitive adhesive composition, any appropriate forming method can be adopted as long as the effects of the present invention are not impaired. Examples of such forming methods include a method (direct method) in which the urethane-based pressure-sensitive adhesive composition is directly applied to any appropriate substrate film (e.g., the substrate layer in a surface protection film according to an embodiment of the present invention) and dried or cured, and a method (transfer method) in which the urethane-based pressure-sensitive adhesive composition is applied to the surface (release surface) of a release liner and dried or cured to form a urethane-based pressure-sensitive adhesive layer on the surface, and the urethane-based pressure-sensitive adhesive layer is then attached to a substrate film (e.g., the substrate layer in a surface protection film according to an embodiment of the present invention) to transfer the urethane-based pressure-sensitive adhesive layer.

[0048] Any appropriate coating method can be used for applying the urethane-based pressure-sensitive adhesive composition as long as it does not impair the effects of the present invention, such as roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, die coating, and roll brush coating.

[0049] The urethane-based pressure-sensitive adhesive composition can be dried under heating (for example, by heating to about 60° C. to 150° C.) as needed.

[0050] Any appropriate curing means may be used to cure the urethane-based pressure-sensitive adhesive composition as long as it does not impair the effects of the present invention, such as ultraviolet irradiation, laser irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation.

[0051] The base polymer (typically at least one selected from a urethane prepolymer and a polyol, which will be described later) preferably contains a polyoxyalkylene structure represented by general formula (1). When the base polymer contains the polyoxyalkylene structure represented by general formula (1), it can exhibit better light release properties. Whether the base polymer contains the polyoxyalkylene structure represented by general formula (1) can be confirmed by any appropriate method. Examples of such methods include NMR measurement and IR measurement. [ka]

[0052] In general formula (1), R 1 represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms. 1 may be the same as or different from each other.

[0053] In general formula (1), R 1 When is an alkyl group having 1 to 4 carbon atoms, examples of the alkyl group include linear alkyl groups such as a methyl group, an ethyl group, and an n-propyl group; and branched alkyl groups such as an isopropyl group, an isobutyl group, and a 2-ethylhexyl group.

[0054] In general formula (1), R 1 When is a hydroxyalkyl group having 1 to 6 carbon atoms, examples of the hydroxyalkyl group include a hydroxymethyl group, a 2-hydroxyethyl group, and a 2-methyl-1,4-hydroxybutyl group.

[0055] R in general formula (1) 1 is preferably one selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably one selected from the group consisting of a hydrogen atom and a methyl group, and even more preferably a hydrogen atom.

[0056] In general formula (1), n ​​is the number of repeating structural units and represents an integer of 1 to 4. In terms of being able to more effectively exhibit the effects of the present invention, n is preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 2.

[0057] In general formula (1), m is the number of repeating structural units and represents an integer of 1 to 200. In terms of being able to further exhibit the effects of the present invention, m is preferably 10 to 100, more preferably 15 to 75, and even more preferably 20 to 50.

[0058] The base polymer (typically at least one selected from a urethane prepolymer and a polyol, which will be described later) preferably contains a polyoxyalkylene structure represented by general formula (2). When the base polymer contains the polyoxyalkylene structure represented by general formula (2), it can exhibit better light release properties. Whether the base polymer contains the polyoxyalkylene structure represented by general formula (2) can be confirmed by any appropriate method. Examples of such methods include NMR measurement and IR measurement. [ka]

[0059] In general formula (2), R 2 represents one selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms. 2 may be the same as or different from each other.

[0060] In general formula (2), R 2 When is an alkyl group having 1 to 4 carbon atoms, examples of the alkyl group include linear alkyl groups such as a methyl group, an ethyl group, and an n-propyl group; and branched alkyl groups such as an isopropyl group and an isobutyl group.

[0061] R in general formula (2) 2is preferably one selected from the group consisting of a hydrogen atom and a methyl group, and more preferably a hydrogen atom.

[0062] In general formula (2), p is the number of repeating structural units and represents an integer of 1 to 300. In terms of being able to further exhibit the effects of the present invention, p is preferably an integer of 10 to 250, more preferably an integer of 20 to 200, and even more preferably an integer of 30 to 150.

[0063] ≪1-1-1. Urethane prepolymer≫ The base polymer includes a urethane prepolymer.

[0064] The urethane prepolymer may be of one type only, or of two or more types.

[0065] The number average molecular weight Mn of the urethane prepolymer is preferably 1,000 to 100,000, in order to more effectively exhibit the effects of the present invention.

[0066] As will be described later, the base polymer may contain a polyol. However, the polyol in the present invention is not a urethane prepolymer. That is, the urethane-based pressure-sensitive adhesive composition may contain a polyol that is not a urethane prepolymer. The reason why the polyol in this specification is defined as not being a urethane prepolymer is as follows. That is, the urethane prepolymer in this specification is what is generally referred to by those skilled in the art in the production of urethane resins as a "urethane prepolymer" (a urethane prepolymer used in the prepolymer method), and is different from a "polyol" (a polyol used in the one-shot method). However, since the urethane prepolymer also has multiple hydroxyl groups, this specification clearly distinguishes between the urethane prepolymer and the polyol.

[0067] The content ratio of urethane prepolymer to polyol in the base polymer is, in terms of weight ratio, preferably urethane prepolymer:polyol=50:50 to 100:0, more preferably urethane prepolymer:polyol=55:45 to 100:0, even more preferably urethane prepolymer:polyol=60:40 to 100:0, particularly preferably urethane prepolymer:polyol=70:30 to 100:0, and most preferably urethane prepolymer:polyol=80:20 to 100:0, in order to further exhibit the effects of the present invention.

[0068] When the base polymer does not contain a polyol, the content of the urethane prepolymer in the urethane pressure-sensitive adhesive composition is preferably 80% by weight to 99.99% by weight, more preferably 85% by weight to 99.99% by weight, even more preferably 90% by weight to 99.99% by weight, and particularly preferably 95% by weight to 99.99% by weight. When the base polymer does not contain a polyol, by adjusting the content of the urethane prepolymer in the urethane pressure-sensitive adhesive composition to fall within the above range, the surface protection film of the present invention can more effectively exhibit the effects of the present invention.

[0069] When the base polymer contains a polyol, the content of the urethane prepolymer in the urethane pressure-sensitive adhesive composition is preferably 40% by weight to 99.98% by weight, more preferably 42% by weight to 99.98% by weight, even more preferably 44% by weight to 99.98% by weight, and particularly preferably 46% by weight to 99.98% by weight. When the base polymer contains a polyol, by adjusting the content of the urethane prepolymer in the urethane pressure-sensitive adhesive composition to fall within the above range, the surface protection film of the present invention can more effectively exhibit the effects of the present invention.

[0070] The urethane prepolymer preferably contains a polyoxyalkylene structure represented by the above general formula (1). When the urethane prepolymer contains a polyoxyalkylene structure represented by the above general formula (1), it can exhibit better light releasability.

[0071] The urethane prepolymer preferably contains a polyoxyalkylene structure represented by the above general formula (2). When the urethane prepolymer contains a polyoxyalkylene structure represented by the above general formula (2), it can further exhibit light releasability.

[0072] Specific preferred embodiments of the urethane prepolymer include: <Embodiment a> A urethane prepolymer (U1) containing a polyoxyalkylene structure represented by the general formula (1) above and not containing a polyoxyalkylene structure represented by the general formula (2) above; <Embodiment b> A urethane prepolymer (U2) containing both the polyoxyalkylene structure represented by the general formula (1) and the polyoxyalkylene structure represented by the general formula (2), <Embodiment c> A urethane prepolymer (U3) containing a polyoxyalkylene structure represented by the general formula (2) above, but not containing a polyoxyalkylene structure represented by the general formula (2) above; Examples include:

[0073] The content ratio of the polyoxyalkylene structure represented by the general formula (1) and the polyoxyalkylene structure represented by the general formula (2) in the urethane prepolymer (U2) can be any appropriate content ratio as long as it does not impair the effects of the present invention. As such a content ratio, the content ratio of the polyoxyalkylene structure represented by the general formula (1) relative to the total amount of the polyoxyalkylene structure represented by the general formula (1) and the polyoxyalkylene structure represented by the general formula (2) is preferably 50% to 99.9% by weight, more preferably 60% to 99% by weight, even more preferably 65% ​​to 98% by weight, and particularly preferably 70% to 95% by weight. By adjusting the content ratio of the polyoxyalkylene structure represented by the general formula (1) relative to the total amount of the polyoxyalkylene structure represented by the general formula (1) and the polyoxyalkylene structure represented by the general formula (2) within the above range, the surface protective film of the present invention can further exhibit the effects of the present invention.

[0074] The urethane prepolymer is typically a polyurethane polyol, and is preferably obtained by reacting at least one selected from polyether polyols and polyester polyols with a polyfunctional isocyanate compound (A) in the presence or absence of a catalyst.

[0075] The polyether polyol may be one kind or two or more kinds.

[0076] The polyester polyol may be one kind or two or more kinds.

[0077] As the urethane prepolymer, a commercially available urethane prepolymer may be used.

[0078] As the polyether polyol, any suitable polyether polyol can be used as long as it does not impair the effects of the present invention. Examples of such polyether polyols include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using a low-molecular-weight polyol such as water, propylene glycol, ethylene glycol, glycerin, or trimethylolpropane as an initiator. Examples of such polyether polyols include polyether polyols having two or more functional groups, such as polypropylene glycol (also referred to as polyoxypropylene glycol), polyethylene glycol (also referred to as polyoxyethylene glycol), polytetramethylene glycol (also referred to as polyoxytetramethylene glycol), and polyoxypropylene triol, and modified products thereof.

[0079] If necessary, a portion of the polyether polyol can be replaced with, for example, glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, and pentaerythritol, or polyvalent amines such as ethylenediamine, N-aminoethylethanolamine, isophoronediamine, and xylylenediamine, and used in combination.

[0080] The number-average molecular weight Mn of the polyether polyol is preferably 500 to 5000, more preferably 1000 to 4500, and even more preferably 1000 to 4000. If the number-average molecular weight is less than 500, the reactivity may be high and gelation may occur easily. If the number-average molecular weight exceeds 5000, the reactivity may be low and the cohesive force of the polyurethane polyol itself may be reduced.

[0081] The polyether polyol may be a bifunctional polyether polyol alone, or a polyether polyol having a number-average molecular weight of 500 to 5,000 and at least three hydroxyl groups per molecule may be used in part or in whole. Using a polyether polyol having an average molecular weight of 500 to 5,000 and at least three hydroxyl groups per molecule in part or in whole can improve the balance between adhesive strength and removability. If such a polyether polyol has a number-average molecular weight of less than 500, the reactivity may be high and gelation may occur easily. If such a polyether polyol has a number-average molecular weight of more than 5,000, the reactivity may be low and the cohesive strength of the urethane prepolymer itself may be reduced.

[0082] Any suitable polyester polyol can be used as the polyester polyol as long as it does not impair the effects of the present invention. Examples of such polyester polyols include polyester polyols obtained by reacting an acid component with a glycol component. Examples of acid components include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of glycol components include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, and butylethylpentanediol. Examples of polyol components include glycerin, trimethylolpropane, and pentaerythritol. In addition to these, examples of polyester polyols include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0083] The number-average molecular weight Mn of the polyester polyol is preferably 500 to 5,000. If the number-average molecular weight is less than 500, the reactivity may be high and gelation may occur easily. If the number-average molecular weight exceeds 5,000, the reactivity may be low and the cohesive force of the polyurethane polyol itself may be reduced. In order to further demonstrate the effects of the present invention, the amount of polyester polyol used is preferably 1 mol % to 90 mol %, more preferably 3 mol % to 70 mol %, even more preferably 5 mol % to 50 mol %, and particularly preferably 7 mol % to 30 mol %, of the total amount of polyether polyol and polyester polyol used as raw materials for the urethane prepolymer.

[0084] When a urethane prepolymer (U1) is used as the urethane prepolymer, the polyol (at least one selected from polyether polyols and polyester polyols) used as a raw material for the urethane prepolymer preferably contains a polyether polyol (PO1) containing a polyoxyalkylene structure represented by the above general formula (1), but does not contain a polyether polyol (PO2) containing a polyoxyalkylene structure represented by the above general formula (2). In this case, the content of the polyether polyol (PO1) in the total amount of polyols (at least one selected from polyether polyols and polyester polyols) used as raw materials for the urethane prepolymer is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, even more preferably 90% to 100% by weight, and most preferably 95% to 100% by weight, in order to further exhibit the effects of the present invention.

[0085] When a urethane prepolymer (U2) is used as the urethane prepolymer, the polyol (at least one selected from polyether polyols and polyester polyols) used as a raw material for the urethane prepolymer preferably includes both a polyether polyol (PO1) containing a polyoxyalkylene structure represented by the above general formula (1) and a polyether polyol (PO2) containing a polyoxyalkylene structure represented by the above general formula (2). In this case, in order to further exhibit the effects of the present invention, the ratio of the polyether polyol (PO1) to the polyether polyol (PO2) used is preferably 50% by weight to 99% by weight, more preferably 60% by weight to 95% by weight, even more preferably 70% by weight to 90% by weight, and particularly preferably 75% by weight to 85% by weight.

[0086] When the urethane prepolymer (U3) is used as the urethane prepolymer, the polyol (at least one selected from polyether polyols and polyester polyols) used as a raw material for the urethane prepolymer preferably contains a polyether polyol (PO2) containing a polyoxyalkylene structure represented by the above general formula (2), but does not contain a polyether polyol (PO1) containing a polyoxyalkylene structure represented by the above general formula (1). In this case, the content of the polyether polyol (PO2) in the total amount of the polyol (at least one selected from polyether polyols and polyester polyols) used as a raw material for the urethane prepolymer is preferably 50% to 100% by weight, more preferably 60% to 100% by weight, even more preferably 70% to 100% by weight, and most preferably 80% to 100% by weight, in order to further exhibit the effects of the present invention.

[0087] Examples of the polyether polyol (PO1) include polytetramethylene glycol (also called polyoxytetramethylene glycol) and modified products thereof.

[0088] The number average molecular weight Mn of the polyether polyol (PO1) is preferably 1000 to 5000, more preferably 1500 to 4500, even more preferably 2000 to 4000, particularly preferably 2200 to 3800, and most preferably 2500 to 3500, in order to further exert the effects of the present invention.

[0089] Examples of polyether polyols (PO2) include polypropylene glycol (also called polyoxypropylene glycol), polyethylene glycol (also called polyoxyethylene glycol), polyoxypropylene triol, and modified products thereof.

[0090] The number average molecular weight Mn of the polyether polyol (PO2) is preferably 500 to 4500, more preferably 600 to 4000, even more preferably 700 to 3500, particularly preferably 800 to 3000, and most preferably 900 to 2500, in order to further exert the effects of the present invention.

[0091] When polyether polyol (PO2) is used as a raw material for the urethane prepolymer (U3), it is preferable to use a polyether polyol (PO2) having a number average molecular weight Mn of 1500 or more in combination with a polyether polyol (PO2) having a number average molecular weight Mn of less than 1500, in order to further enhance the effects of the present invention. In this case, the content of polyether polyol (PO2) having a number average molecular weight Mn of 1500 or more in the total amount of polyether polyol (PO2) used as a raw material for the urethane prepolymer (U3) is preferably 10% by weight to 90% by weight, more preferably 20% by weight to 80% by weight, even more preferably 30% by weight to 70% by weight, and most preferably 40% by weight to 60% by weight.

[0092] Any appropriate polyfunctional isocyanate compound can be used as the polyfunctional isocyanate compound (A) as long as it does not impair the effects of the present invention. Examples of such polyfunctional isocyanate compound (A) include aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates.

[0093] Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4"-triphenylmethane triisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

[0094] Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0095] Examples of the aromatic aliphatic polyisocyanate include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate.

[0096] Examples of alicyclic polyisocyanates include 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatemethyl)cyclohexane, 1,4-bis(isocyanatemethyl)cyclohexane, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

[0097] Examples of the polyfunctional isocyanate compound (A) include trimethylolpropane adducts of the various polyfunctional isocyanate compounds described above, biuret compounds obtained by reacting with water, and trimers having an isocyanurate ring. These compounds can also be used in combination.

[0098] Any suitable catalyst can be used when producing the urethane prepolymer as long as it does not impair the effects of the present invention. Examples of such catalysts include tertiary amine compounds and organometallic compounds. The catalyst may be one type or two or more types.

[0099] Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7(DBU).

[0100] Examples of organometallic compounds include tin-based compounds and non-tin-based compounds.

[0101] Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

[0102] Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanium, and butoxytitanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium compounds such as zirconium naphthenate.

[0103] As the catalyst, a tin-based compound is preferably used from the viewpoint of further exhibiting the effects of the present invention, while a non-tin-based compound is preferably used from the viewpoint of environmental protection.

[0104] When a catalyst is used in producing the urethane prepolymer, the amount of the catalyst used is preferably 0.01 to 1.0% by weight based on the total amount of the polyol (at least one selected from polyether polyols and polyester polyols) and the polyfunctional isocyanate compound (A) as raw materials for the urethane prepolymer.

[0105] When a catalyst is used in producing the urethane prepolymer, the reaction temperature is preferably less than 100° C., and more preferably 85 to 95° C. If the temperature is 100° C. or higher, it may become difficult to control the reaction rate and crosslinked structure, and it may become difficult to obtain a urethane prepolymer having the desired molecular weight.

[0106] When producing a urethane prepolymer, it is not necessary to use a catalyst. In that case, the reaction temperature is preferably 100°C or higher, more preferably 110°C or higher. When obtaining a urethane prepolymer without a catalyst, the reaction is preferably carried out for 3 hours or longer.

[0107] Examples of methods for producing a urethane prepolymer include: 1) a method in which a polyol (at least one selected from polyether polyols and polyester polyols) as raw materials, a catalyst, and a polyfunctional isocyanate compound (A) are all charged into a reactor, and 2) a method in which a polyol (at least one selected from polyether polyols and polyester polyols) as raw materials and a catalyst are charged into a reactor, and then the polyfunctional isocyanate compound (A) is added dropwise. Method 2) is preferred as a method for producing a urethane prepolymer in terms of reaction control.

[0108] When producing the urethane prepolymer, any appropriate solvent can be used as long as it does not impair the effects of the present invention. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Among these solvents, ethyl acetate and toluene are preferred.

[0109] ≪1-1-2. Polyol≫ The base polymer may contain a polyol, provided that, as mentioned above, the polyol in the present invention is not a urethane prepolymer.

[0110] When the base polymer contains a polyol, the content of the polyol in the urethane-based pressure-sensitive adhesive composition is preferably 0.02 to 80% by weight, more preferably 0.02 to 70% by weight, even more preferably 0.02 to 60% by weight, and particularly preferably 0.02 to 55% by weight. When the base polymer contains a polyol, by adjusting the content of the polyol in the urethane-based pressure-sensitive adhesive composition to fall within the above range, the surface protection film of the present invention can more effectively exhibit the effects of the present invention.

[0111] Examples of polyols include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil polyols. More preferred polyols are polyester polyols and polyether polyols.

[0112] The polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

[0113] Examples of polyol components include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol.

[0114] Examples of the acid component include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and acid anhydrides thereof.

[0115] Examples of polyether polyols include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide using water, low-molecular-weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcinol, hydroquinone, etc.) as initiators. Specific examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0116] Examples of polycaprolactone polyols include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

[0117] Examples of polycarbonate polyols include polycarbonate polyols obtained by polycondensation of the above polyol components with phosgene; polycarbonate polyols obtained by transesterification of the above polyol components with carbonate diesters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and dibenzyl carbonate; copolymer polycarbonate polyols obtained by combining two or more of the above polyol components; polycarbonate polyols obtained by esterification of the above various polycarbonate polyols with carboxyl group-containing compounds; and various of the above various Examples of the polycarbonate polyol include polycarbonate polyols obtained by etherifying polycarbonate polyols with hydroxyl group-containing compounds; polycarbonate polyols obtained by transesterifying the above-mentioned various polycarbonate polyols with ester compounds; polycarbonate polyols obtained by transesterifying the above-mentioned various polycarbonate polyols with hydroxyl group-containing compounds; polyester-based polycarbonate polyols obtained by polycondensation of the above-mentioned various polycarbonate polyols with dicarboxylic acid compounds; and copolymerized polyether-based polycarbonate polyols obtained by copolymerizing the above-mentioned various polycarbonate polyols with alkylene oxides.

[0118] Examples of castor oil-based polyols include castor oil-based polyols obtained by reacting castor oil fatty acids with the above-mentioned polyol components.Specific examples include castor oil-based polyols obtained by reacting castor oil fatty acids with polypropylene glycol.

[0119] As the polyol, a polyether polyol (PO1) containing a polyoxyalkylene structure represented by the above general formula (1) may be used.

[0120] As mentioned above, examples of the polyether polyol (PO1) include polytetramethylene glycol (also called polyoxytetramethylene glycol) and modified products thereof.

[0121] The polyol preferably contains a first polyol having a number average molecular weight Mn of 5,000 to 20,000 and a second polyol having a number average molecular weight Mn of 300 to 4,999, in that the effects of the present invention can be more effectively exhibited.

[0122] The first polyol A1 may be of only one type, or of two or more types.

[0123] The second polyol A2 may be one type only, or two or more types.

[0124] The total content ratio of the first polyol and the second polyol in the polyol is preferably 80% by weight to 100% by weight, more preferably 90% by weight to 100% by weight, even more preferably 95% by weight to 100% by weight, particularly preferably 98% by weight to 100% by weight, and most preferably substantially 100% by weight, in order to further exhibit the effects of the present invention.

[0125] The number average molecular weight Mn of the first polyol is 5000 to 20000, preferably 6000 to 18000, more preferably 7000 to 16000, still more preferably 8000 to 15000, and particularly preferably 9000 to 14000. When the number average molecular weight Mn of the first polyol is within the above range, the effects of the present invention can be more effectively exhibited.

[0126] The number average molecular weight Mn of the second polyol is 300 to 4999, preferably 500 to 4500, more preferably 1000 to 4000, still more preferably 1500 to 3800, and particularly preferably 2000 to 3500. When the number average molecular weight Mn of the second polyol is within the above range, the effects of the present invention can be more effectively exhibited.

[0127] The weight ratio of the first polyol to the second polyol is preferably 0.7 ≦ (first polyol / second polyol) ≦ 3.5, more preferably 1.0 ≦ (first polyol / second polyol) ≦ 3.0, even more preferably 1.1 ≦ (first polyol / second polyol) ≦ 2.5, and particularly preferably 1.2 ≦ (first polyol / second polyol) ≦ 2.0. When the weight ratio of the first polyol to the second polyol is within the above range, the surface protection film according to the embodiment of the present invention can achieve excellent low haze and, for example, can exhibit excellent inspectability.

[0128] The first polyol preferably has 3 to 6 OH groups, more preferably 3 to 5 OH groups, even more preferably 3 to 4 OH groups, and particularly preferably 3 OH groups, in order to further exert the effects of the present invention.

[0129] The first polyol preferably contains 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably substantially 100% by weight of a triol having three OH groups, in order to further exert the effects of the present invention.

[0130] The second polyol preferably has 3 to 6 OH groups, more preferably 3 to 5 OH groups, even more preferably 3 to 4 OH groups, and particularly preferably 3 OH groups, in order to further exert the effects of the present invention.

[0131] The second polyol preferably contains 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably substantially 100% by weight, of a triol having three OH groups, in order to further exert the effects of the present invention.

[0132] 1-1-3. Polyfunctional isocyanate compounds (B) The urethane-based pressure-sensitive adhesive composition preferably contains a polyfunctional isocyanate compound (B). When the urethane-based pressure-sensitive adhesive composition contains the polyfunctional isocyanate compound (B), a crosslinking reaction occurs between the urethane prepolymer contained in the urethane-based pressure-sensitive adhesive composition and a polyol that may be contained as an optional component, thereby forming a urethane-based pressure-sensitive adhesive.

[0133] The polyfunctional isocyanate compound (B) may be of one type only, or of two or more types.

[0134] Any suitable polyfunctional isocyanate compound that can be used in a urethanization reaction can be used as the polyfunctional isocyanate compound (B). Examples of such polyfunctional isocyanate compounds (B) include aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates.

[0135] Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4"-triphenylmethane triisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

[0136] Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0137] Examples of the aromatic aliphatic polyisocyanate include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate.

[0138] Examples of alicyclic polyisocyanates include 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatemethyl)cyclohexane, 1,4-bis(isocyanatemethyl)cyclohexane, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

[0139] Examples of the polyfunctional isocyanate compound (B) include trimethylolpropane adducts of the various polyfunctional isocyanate compounds described above, biuret compounds obtained by reacting with water, and trimers having an isocyanurate ring. These compounds can also be used in combination.

[0140] The content of the polyfunctional isocyanate compound (B) in the urethane-based pressure-sensitive adhesive composition is preferably 2.0 to 40 parts by weight, more preferably 2.3 to 30 parts by weight, even more preferably 2.5 to 20 parts by weight, and particularly preferably 3.0 to 15 parts by weight, relative to 100 parts by weight of the base polymer, in order to further exhibit the effects of the present invention.

[0141] The equivalent ratio of NCO groups to OH groups in the urethane-based pressure-sensitive adhesive composition is preferably 1.0 to 2.0, more preferably 1.1 to 1.9, even more preferably 1.2 to 1.8, and particularly preferably 1.2 to 1.7, in terms of NCO groups / OH groups, in order to further exhibit the effects of the present invention.

[0142] 1-1-4. Fluorine-based compounds The urethane-based pressure-sensitive adhesive composition contains a fluorine-based compound. When the urethane-based pressure-sensitive adhesive composition contains a fluorine-based compound, the effects of the present invention can be more effectively exhibited.

[0143] The fluorine-based compound may be one kind or two or more kinds.

[0144] The content of the fluorine-based compound in the urethane-based pressure-sensitive adhesive composition is preferably 0.01 part by weight or more, more preferably 0.03 to 30 parts by weight, even more preferably 0.05 to 10 parts by weight, and particularly preferably 0.05 to 1 part by weight, relative to 100 parts by weight of the base polymer, in order to further exhibit the effects of the present invention.

[0145] The fluorine-based compound preferably has a surface tension of 23 mN / m or more, more preferably 23 mN / m to 26 mN / m when dissolved in a 0.1% propylene glycol monomethyl ether solution (the surface tension of propylene glycol monomethyl ether is 27.1 mN / m). By controlling the surface tension of the fluorine-based compound when dissolved in a 0.1% propylene glycol monomethyl ether solution within the above range, the effects of the present invention can be more effectively exhibited. In particular, by controlling the surface tension of the fluorine-based compound when dissolved in a 0.1% propylene glycol monomethyl ether solution within the above range, the occurrence of black spots can be more effectively suppressed.

[0146] The fluorine-based compound may be, for example, at least one selected from a fluorine-containing compound, a hydroxyl group-containing fluorine-based compound, and a crosslinkable functional group-containing fluorine-based compound.

[0147] Examples of fluorine-containing compounds include compounds having a fluoroaliphatic hydrocarbon skeleton, fluorine-containing organic compounds obtained by copolymerizing an organic compound with a fluorine-based compound, and fluorine-containing compounds containing an organic compound. Examples of fluoroaliphatic hydrocarbon skeletons include fluoro C1-C10 alkanes such as fluoromethane, fluoroethane, fluoropropane, fluoroisopropane, fluorobutane, fluoroisobutane, fluoro t-butane, fluoropentane, and fluorohexane. Here, the term "C1-C10" means that the number of carbon atoms is 1 to 10.

[0148] A preferred embodiment of the fluorine-containing compound is an oligomer having a fluorine-containing group and a hydrophilic group and / or a lipophilic group ("specific fluorine-based compound").

[0149] Representative examples of the fluorine-containing group include a fluorine-containing alkyl group (such as CF3-) and / or a fluorine-containing alkylene group (such as -CF2-CF2-).

[0150] A hydrophilic group is a group having hydrophilic properties, and hydrophilicity is translated into English as "hydrophilic," a property generally known to those skilled in the art as meaning "having an affinity for water" (see, for example, McGraw-Hill Scientific and Technical Dictionary (Revised 3rd Edition, Nikkan Kogyo Shimbun, Ltd.)). A lipophilic group is a group having lipophilic properties, and lipophilicity is translated into English as "lipophilic," a property generally known to those skilled in the art as meaning "having an affinity for oil" (see, for example, McGraw-Hill Scientific and Technical Dictionary (Revised 3rd Edition, Nikkan Kogyo Shimbun, Ltd.)).

[0151] The use of such a "specific fluorine-based compound" as the fluorine-based compound can further enhance the effects of the present invention. In particular, the use of a "specific fluorine-based compound" as the fluorine-based compound can enable the surface protection film according to the embodiment of the present invention to exhibit excellent easy peelability.

[0152] The use of such a "specific fluorine-based compound" in combination with an ionic compound described below can further improve the antistatic performance of the surface protection film according to an embodiment of the present invention. This is presumably because the specific fluorine-based compound causes the ionic compound to be unevenly distributed on the surface side of the urethane-based pressure-sensitive adhesive layer (the side that is bonded to the adherend).

[0153] As commercially available fluorine-containing compounds, for example, the following may be mentioned:

[0154] DIC Corporation's Megafuck series: Representative examples include "Megafac F-114", "Megafac F-253", "Megafac F-281", "Megafac F-410", "Megafac F-430", "Megafac F-444", "Megafac F-477", "Megafac F-510", "Megafac F-551", "Megafac F-553", "Megafac F-554", "Megafac F-556", "Megafac F-557", "Megafac F-559", "Megafac F-561", and "Megafac F -562", "Megafac F-565", "Megafac F-568", "Megafac F-570", "Megafac F-571", "Megafac F-576", "Megafac R-01", "Megafac R-40", "Megafac R-40-LM", "Megafac R-41", "Megafac R-41-LM", "Megafac R-94", "Megafac RS-56", "Megafac RS-72-K", "Megafac RS-75-A", "Megafac RS-75-NS", etc.

[0155] AGC Seimi Chemical Co., Ltd.'s Surflon series: Representative examples include "S-242", "S-243", and "S-386".

[0156] Sumitomo 3M FC series: Representative examples include "FC-4430" and "FC-4432".

[0157] Neos Ftergent series: Representative examples include "Ftergent 100," "Ftergent 100C," "Ftergent 110," "Ftergent 150," "Ftergent 150CH," "Ftergent 250," and "Ftergent 400SW."

[0158] Kitamura Chemical Industry Co., Ltd. PF series: Representative examples include "PF-136A", "PF-156A", "PF-151N", "PF-636", "PF-6320", "PF-656", "PF-6520", "PF-651", "PF-652", and "PF-3320".

[0159] Examples of the hydroxyl-containing fluorine-based compound include conventionally known resins, such as those described in International Publication No. 94 / 06870, Japanese Patent Application Laid-Open No. 8-12921, Japanese Patent Application Laid-Open No. 10-72569, Japanese Patent Application Laid-Open No. 4-275379, International Publication No. 97 / 11130, and International Publication No. 96 / 26254. Other hydroxyl-containing fluorine-based resins include the fluoroolefin copolymers described in Japanese Patent Application Laid-Open No. 8-231919, Japanese Patent Application Laid-Open No. 10-265731, Japanese Patent Application Laid-Open No. 10-204374, and Japanese Patent Application Laid-Open No. 8-12922. Other examples include copolymers of a compound having a fluorinated alkyl group in a hydroxyl-containing compound, fluorine-containing organic compounds in which a hydroxyl-containing compound is copolymerized with a fluorine-containing compound, and fluorine-containing compounds containing a hydroxyl-containing organic compound. Commercially available examples of such hydroxyl group-containing fluorine-based compounds include those sold under the trade name "Lumiflon" (manufactured by Asahi Glass Co., Ltd.), "Cefralcoat" (manufactured by Central Glass Co., Ltd.), "Zaflon" (manufactured by Toa Gosei Co., Ltd.), and "Zeffle" (manufactured by Daikin Industries, Ltd.).

[0160] Examples of fluorine-based compounds containing crosslinkable functional groups include carboxylic acid compounds having a fluorinated alkyl group such as perfluorooctanoic acid, copolymers of compounds having a fluorinated alkyl group with a crosslinkable functional group-containing compound, fluorine-containing organic compounds obtained by copolymerizing a fluorine-containing compound with a crosslinkable functional group-containing compound, and fluorine-containing compounds containing a crosslinkable functional group-containing compound. Commercially available examples of such fluorine-based compounds containing crosslinkable functional groups include those under the trade names "Megafac F-570," "Megafac RS-55," "Megafac RS-56," "Megafac RS-72-K," "Megafac RS-75," "Megafac RS-76-E," "Megafac RS-76-NS," "Megafac RS-78," and "Megafac RS-90" (manufactured by DIC Corporation).

[0161] Among commercially available fluorine-containing compounds, a representative example of the "oligomer having a fluorine-containing group and a hydrophilic group and / or a lipophilic group" is the following, manufactured by DIC Corporation: "Megafac F-251" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 22.7 mN / m), "Megafac F-477" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 25.4 mN / m), "Megafac F-551" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 25.9 mN / m), "Megafac F-553" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 25.4 mN / m), "Megafac F-554" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 25.0 mN / m), "Megafac F-555" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 20.5 mN / m), "Megafac F-557" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 25.6 mN / m), "Megafac F-559" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 24.3 mN / m), "Megafac F-563" (a fluorine-containing, lipophilic group-containing oligomer, surface tension of 21.4 mN / m when dissolved in 0.1% propylene glycol monomethyl ether), "Megafac F-569" (fluorine-containing and hydrophilic group-containing oligomer, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 19.7 mN / m), "Megafac F-571" (fluorine-containing and hydrophilic group-containing oligomer, surface tension when dissolved in 0.1% propylene glycol monomethyl ether = 24.2 mN / m), Examples include:

[0162] 1-1-5. Ionic Compounds The urethane-based pressure-sensitive adhesive composition may contain an ionic compound. When the urethane-based pressure-sensitive adhesive composition contains an ionic compound, the antistatic performance of the surface protection film according to the embodiment of the present invention may be improved.

[0163] The content of the ionic compound may be any appropriate content ratio as long as it does not impair the effects of the present invention. To further improve the antistatic performance of the surface protective film of the present invention, the content of the ionic compound in the urethane-based pressure-sensitive adhesive composition is preferably 0.05 parts by weight or more, more preferably 0.10 to 50 parts by weight, even more preferably 0.20 to 30 parts by weight, particularly preferably 0.30 to 10 parts by weight, and most preferably 0.40 to 1 part by weight, relative to 100 parts by weight of the base polymer. If the content of the ionic compound in the urethane-based pressure-sensitive adhesive composition is too low outside the above range, the surface protective film of the present invention may not be able to achieve sufficient antistatic performance. If the content of the ionic compound in the urethane-based pressure-sensitive adhesive composition is too high outside the above range, the adherend may be subject to increased contamination.

[0164] As the ionic compound, any appropriate ionic compound can be adopted as long as it does not impair the effects of the present invention.

[0165] The ionic compound may be of only one type, or of two or more types.

[0166] As the ionic compound, in terms of being able to further exhibit the effects of the present invention, preferred are ionic compounds containing at least one selected from onium cations and metal cations and a fluoroorganic anion, and ionic group-containing silicone oligomers, and in terms of being able to further improve the appearance of the pressure-sensitive adhesive layer, more preferred are ionic compounds containing at least one selected from onium cations and metal cations and a fluoroorganic anion.

[0167] The ionic compound may be an ionic liquid, which means a molten salt (ionic compound) that is liquid at 25°C.

[0168] As the ionic group-containing silicone oligomer, any suitable ionic group-containing silicone oligomer can be used as long as it does not impair the effects of the present invention. An example of an ionic group-containing silicone oligomer is "X-40-2450" manufactured by Shin-Etsu Chemical Co., Ltd.

[0169] As the onium cation, any appropriate onium cation can be used as long as it does not impair the effects of the present invention. In terms of further exhibiting the effects of the present invention, such an onium cation is preferably at least one selected from ammonium cations (nitrogen-containing onium cations), sulfonium cations (sulfur-containing onium cations), and phosphorus-containing onium cations (phosphonium cations), and more preferably ammonium cations.

[0170] As the metal cation, any appropriate metal cation can be used as long as it does not impair the effects of the present invention. In terms of being able to further exhibit the effects of the present invention, such metal cation is preferably an alkali metal cation such as a Li cation, a Na cation, or a K cation.

[0171] As the fluoroorganic anion, any appropriate fluoroorganic anion can be used as long as it does not impair the effects of the present invention. The fluoroorganic anion may be completely fluorinated (perfluorinated) or partially fluorinated.

[0172] Examples of such fluoroorganic anions include fluorinated arylsulfonates, perfluoroalkanesulfonates, bis(fluorosulfonyl)imides, bis(perfluoroalkanesulfonyl)imides, cyanoperfluoroalkanesulfonylamides, bis(cyano)perfluoroalkanesulfonylmethides, cyano-bis-(perfluoroalkanesulfonyl)methides, tris(perfluoroalkanesulfonyl)methides, trifluoroacetates, perfluoroalkylates, tris(perfluoroalkanesulfonyl)methides, and (perfluoroalkanesulfonyl)trifluoroacetamides.

[0173] Among these fluoroorganic anions, perfluoroalkylsulfonates, bis(fluorosulfonyl)imides, and bis(perfluoroalkanesulfonyl)imides are preferred, as they can further exert the effects of the present invention. More specifically, for example, trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, nonafluorobutanesulfonate, bis(fluorosulfonyl)imide, and bis(trifluoromethanesulfonyl)imide are preferred, and bis(fluorosulfonyl)imide and bis(trifluoromethanesulfonyl)imide are preferred.

[0174] As the ionic compound, an ionic compound composed of an onium cation and an organic fluoro anion is more preferred, as it can more effectively exhibit the effects of the present invention.

[0175] The onium cation preferably has at least one type selected from the structures represented by general formulas (3) to (6). [ka]

[0176] In general formula (3), Ra represents a hydrocarbon group having 4 to 20 carbon atoms, which may contain a heteroatom, and Rb and Rc are the same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom, provided that when the nitrogen atom contains a double bond, Rc does not exist.

[0177] In general formula (4), Rd represents a hydrocarbon group having 2 to 20 carbon atoms, which may contain a heteroatom, and Re, Rf, and Rg may be the same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom.

[0178] In general formula (5), Rh represents a hydrocarbon group having 2 to 20 carbon atoms, which may contain a heteroatom, and Ri, Rj, and Rk may be the same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom.

[0179] In general formula (6), Z represents a nitrogen atom, a sulfur atom, or a phosphorus atom, and Rl, Rm, Rn, and Ro are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom, provided that when Z is a sulfur atom, Ro does not exist.

[0180] Examples of the cation structure represented by general formula (3) include a pyridinium cation structure, a pyrrolidinium cation structure, a piperidinium cation structure, a cation structure having a pyrroline skeleton, and a cation structure having a pyrrole skeleton.

[0181] Specific examples of the cation represented by general formula (3) include pyridinium cations such as 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-octyl-4-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, and 1,1-dimethylpyrrolidinium cation; 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation, 1-ethyl-1-propylpyrrolidinium cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium pyrrolidinium cations such as 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, and 1,1-dibutylpyrrolidinium cation; 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, and 1-methyl-1- piperidinium cations such as heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1,1-dipropylpiperidinium cation, and 1,1-dibutylpiperidinium cation; 2-methyl-1-pyrroline cation;Examples include 1-ethyl-2-phenylindole cation; 1,2-dimethylindole cation; 1-ethylcarbazole cation; and cations which further contain at least one group selected from the group consisting of a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group).

[0182] Among these, in terms of further exhibiting the effects of the present invention, preferred are pyridinium cations such as 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, and 1-octyl-4-methylpyridinium cation; 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation, 1-ethyl-1-propylpyrrolidinium cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl ... and 1-ethyl-1-pentylpyrrolidinium cation. pyrrolidinium cations such as 1-ethyl-1-hexylpyrrolidinium cation and 1-ethyl-1-heptylpyrrolidinium cation; piperidinium cations such as 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, and 1-propyl-1-butylpiperidinium cation; cations such as these cations further having at least one selected from a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group);More preferred are 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-octyl-4-methylpyridinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl-1-propylpiperidinium cation, and cations which further have at least one selected from a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group);

[0183] Examples of the cation structure represented by general formula (4) include an imidazolium cation structure, a tetrahydropyrimidinium cation structure, and a dihydropyrimidinium cation structure.

[0184] Specific examples of the cation represented by general formula (4) include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, and imidazolium cations such as 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, and 1-hexyl-2,3-dimethylimidazolium cation; 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5, tetrahydropyrimidinium cations such as 1,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation; dihydropyrimidinium cations such as 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation; and cations such as these cations further having at least one selected from a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group).

[0185] Among these, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, and 1-methylimidazolium cation are preferred, as they can more effectively exhibit the effects of the present invention. imidazolium cations such as the methylimidazolium cation, or cations which further have at least one selected from a vinyl group (CH2=CH- group) and an allyl group (CH2=CH-CH2- group), and more preferably the 1-ethyl-3-methylimidazolium cation, the 1-hexyl-3-methylimidazolium cation, or cations which further have at least one selected from a vinyl group (CH2=CH- group) and an allyl group (CH2=CH-CH2- group).

[0186] Examples of the cation structure represented by general formula (5) include a pyrazolium cation structure and a pyrazolinium cation structure.

[0187] Specific examples of the cation represented by general formula (5) include pyrazolium cations such as a 1-methylpyrazolium cation, a 3-methylpyrazolium cation, a 1-ethyl-2-methylpyrazolinium cation, a 1-ethyl-2,3,5-trimethylpyrazolium cation, a 1-propyl-2,3,5-trimethylpyrazolium cation, and a 1-butyl-2,3,5-trimethylpyrazolium cation; pyrazolinium cations such as a 1-ethyl-2,3,5-trimethylpyrazolinium cation, a 1-propyl-2,3,5-trimethylpyrazolinium cation, and a 1-butyl-2,3,5-trimethylpyrazolinium cation; and cations in which these cations further have at least one selected from a vinyl group (CH═CH— group) and an allyl group (CH═CH—CH— group).

[0188] Examples of the cation structure represented by general formula (6) include a tetraalkylammonium cation structure, a trialkylsulfonium cation structure, a tetraalkylphosphonium cation structure, and structures in which a portion of the alkyl groups is substituted with an alkenyl group, an alkoxyl group, or an epoxy group.

[0189] Specific examples of the cation represented by general formula (6) include tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethylpropylammonium cation, trimethyldecylammonium cation, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N,N-dimethyl-N-ethyl-N-propylammonium cation, N,N-dimethyl-N-ethyl-N-butylammonium cation, N,N-dimethyl-N-ethyl-N-pentylammonium cation, N,N-dimethyl-N-ethyl-N-hexylammonium cation, N,N-dimethyl-N-ethyl-N-heptylammonium cation, N,N-dimethyl-N-ethyl-N-nonylammonium cation, and N,N-dimethyl- N,N-dipropylammonium cation, N,N-diethyl-N-propyl-N-butylammonium cation, N,N-dimethyl-N-propyl-N-pentylammonium cation, N,N-dimethyl-N-propyl-N-hexylammonium cation, N,N-dimethyl-N-propyl-N-heptylammonium cation, N,N-dimethyl-N-butyl-N-hexylammonium cation, N,N-diethyl-N-butyl-N-heptylammonium cation, N,N-dimethyl-N-pentyl-N-hexylammonium cation Thione, N,N-dimethyl-N,N-dihexylammonium cation, trimethylheptylammonium cation, N,N-diethyl-N-methyl-N-propylammonium cation, N,N-diethyl-N-methyl-N-pentylammonium cation, N,N-diethyl-N-methyl-N-heptylammonium cation, N,N-diethyl-N-propyl-N-pentylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylheptylammonium cation, N,Tetraalkylammonium cations such as N-dipropyl-N-methyl-N-ethylammonium cation, N,N-dipropyl-N-methyl-N-pentylammonium cation, N,N-dipropyl-N-butyl-N-hexylammonium cation, N,N-dipropyl-N,N-dihexylammonium cation, N,N-dibutyl-N-methyl-N-pentylammonium cation, N,N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethylammonium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation; trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, etc. trialkylsulfonium cations such as sulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, and dimethyldecylsulfonium cation; tetraalkylphosphonium cations such as tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, and trimethyldecylphosphonium cation; and cations in which these cations further have at least one selected from a vinyl group (CH═CH- group) and an allyl group (CH═CH-CH- group).

[0190] The ionic compound is preferably an ionic compound containing at least one selected from the above onium cations and metal cations and the above fluoroorganic anion, or an ionic group-containing silicone oligomer, more preferably an ionic compound containing at least one selected from the above onium cations and metal cations and the above fluoroorganic anion, and even more preferably an ionic compound containing the above onium cation and the above fluoroorganic anion.

[0191] In terms of being able to further exhibit the effects of the present invention, the ionic compound is preferably, specifically, 1-hexylpyridinium bis(fluorosulfonyl)imide, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium pentafluoroethanesulfonate, 1-ethyl-3-methylpyridinium heptafluoropropanesulfonate, 1-ethyl-3-methylpyridinium nonafluorobutanesulfonate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis(fluorosulfonyl)imide, 1-ethyl-3-methylpyridinium trifluorom ... bis(fluorosulfonyl)imide, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyrid 1-octyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-octyl-4-methylpyridinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide, 1-ethyl-3-methylimidazolium 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-Ethyl-3-methylimidazolium heptafluoropropanesulfonate, 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-Hexyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-Allyl-3-methylimidazolium trifluoromethanesulfonate, 1-Allyl-3-methylimidazolium heptafluoropropanesulfonate, 1-Allyl- 3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide, 1-allyl-3-methyl-imidazolium bis(fluorosulfonyl)imide, methyltrioctylammonium bis(trifluoromethanesulfonyl)imide, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, more preferably 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide,1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-allyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide, methyltrioctylammonium bis(trifluoromethanesulfonyl)imide, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide are preferred, and 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-allyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide, methyltrioctylammonium bis(trifluoromethanesulfonyl)imide, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide are particularly preferred.

[0192] The ionic compound may be commercially available or synthesized by any suitable method. For example, the ionic liquid may be synthesized by a halide method, a hydroxide method, an acid ester method, a complex formation method, a neutralization method, or the like, as described in "Ionic Liquids - The Frontline and Future of Development" (published by CMC Publishing).

[0193] ≪1-1-6. Other ingredients≫ The urethane-based 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 resin components other than the base polymer, crosslinking agents other than the polyfunctional isocyanate compound (B), crosslinking retarders, silicone additives, fatty acid esters, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foil-like materials, softeners, antioxidants, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, catalysts, and solvents. Representative other components are described below.

[0194] [Silicone additives] In one preferred embodiment, the urethane-based pressure-sensitive adhesive composition contains a silicone-based additive. When the urethane-based pressure-sensitive adhesive composition contains a silicone-based additive as another component, the easy peelability of the surface protection film according to the embodiment of the present invention can be further improved.

[0195] In order to further exert the effects of the present invention, the content of the silicone additive in the urethane-based pressure-sensitive adhesive composition is preferably 0.01 part by weight or more, more preferably 0.03 to 30 parts by weight, even more preferably 0.05 to 10 parts by weight, and particularly preferably 0.05 to 1 part by weight, relative to 100 parts by weight of the base polymer.

[0196] As the silicone-based additive, any appropriate silicone-based additive can be used as long as it does not impair the effects of the present invention.

[0197] The silicone-based additive may be of only one type, or may be of two or more types.

[0198] In order to further exert the effects of the present invention, the total content ratio of the silicone-based additive and the above-mentioned fluorine-based additive is preferably 0.01 part by weight or more, more preferably 0.03 to 30 parts by weight, even more preferably 0.05 to 10 parts by weight, and particularly preferably 0.05 to 1 part by weight, relative to 100 parts by weight of the base polymer.

[0199] Any suitable silicone-based additive may be used as long as it does not impair the effects of the present invention. Examples of such silicone-based additives include reactive silicone oils and non-reactive silicone oils.

[0200] Examples of reactive silicone oils include side-chain reactive silicone oils in which an organic group is bonded as a side chain to a Si atom that participates in a siloxane bond; double-end reactive silicone oils in which an organic group is bonded to Si atoms located at both ends of the structure; single-end reactive silicone oils in which an organic group is bonded to only one of the Si atoms located at both ends of the structure; and side-chain double-end reactive silicone oils in which an organic group is bonded as a side chain to a Si atom that participates in a siloxane bond and organic groups are bonded to Si atoms located at both ends of the structure.

[0201] [Antioxidants] The urethane-based pressure-sensitive adhesive composition may contain an antioxidant as another component from the viewpoint of suppressing deterioration of the urethane-based pressure-sensitive adhesive layer, etc. The antioxidant may be one type only, or two or more types may be used.

[0202] The content of the antioxidant in the urethane-based pressure-sensitive adhesive composition may be any appropriate content ratio as long as the effects of the present invention are not impaired. The content of the antioxidant in the urethane-based pressure-sensitive adhesive composition is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, even more preferably 0.1 to 3 parts by weight, and particularly preferably 0.2 to 1 part by weight, relative to 100 parts by weight of the base polymer.

[0203] Examples of antioxidants include radical chain inhibitors and peroxide decomposers.

[0204] Examples of the radical chain inhibitor include phenol-based antioxidants and amine-based antioxidants.

[0205] Examples of peroxide decomposers include sulfur-based antioxidants and phosphorus-based antioxidants.

[0206] Examples of the phenol-based antioxidant include monophenol-based antioxidants, bisphenol-based antioxidants, and polymeric phenol-based antioxidants.

[0207] Examples of monophenol-based antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, and stearin-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate.

[0208] Examples of bisphenol antioxidants include 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), and 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane.

[0209] Examples of polymeric phenolic antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocophenol.

[0210] Examples of sulfur-based antioxidants include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3'-thiodipropionate.

[0211] Examples of phosphorus-based antioxidants include triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite.

[0212] [Ultraviolet absorber] The urethane-based pressure-sensitive adhesive composition may contain an ultraviolet absorber as another component from the viewpoint of suppressing deterioration of the urethane-based pressure-sensitive adhesive layer, etc. The ultraviolet absorber may be one type only, or two or more types.

[0213] The content of the ultraviolet absorber in the urethane-based pressure-sensitive adhesive composition may be any appropriate content ratio as long as the effects of the present invention are not impaired. The content of the ultraviolet absorber in the urethane-based pressure-sensitive adhesive composition is preferably 0.01 to 10 parts by weight or more, more preferably 0.05 to 5 parts by weight, even more preferably 0.1 to 3 parts by weight, and particularly preferably 0.2 to 1 part by weight, relative to 100 parts by weight of the base polymer.

[0214] Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, oxalic acid anilide-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

[0215] Examples of benzophenone-based ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, and bis(2-methoxy-4-hydroxy-5-benzoylphenyl)methane.

[0216] Examples of the benzotriazole-based ultraviolet absorber include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)5-chlorobenzotriazole, 2-(2'-hydroxy Examples of suitable benzotriazoles include 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, 2-[2'-hydroxy-3'-(3'',4'',5'',6'',-tetrahydrophthalimidomethyl)-5'-methylphenyl]benzotriazole, 2,2'methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], and [2(2'-hydroxy-5'-methacryloxyphenyl)-2H-benzotriazole].

[0217] Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

[0218] Examples of cyanoacrylate ultraviolet absorbers include 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate and ethyl-2-cyano-3,3'-diphenylacrylate.

[0219] [Light stabilizer] The urethane-based pressure-sensitive adhesive composition may contain a light stabilizer as another component from the viewpoint of suppressing deterioration of the urethane-based pressure-sensitive adhesive layer, etc. The light stabilizer may be one type only, or two or more types may be used.

[0220] The content of the light stabilizer in the urethane-based pressure-sensitive adhesive composition may be any appropriate content ratio as long as the effects of the present invention are not impaired. The content of the light stabilizer in the urethane-based pressure-sensitive adhesive composition is preferably 0.01 to 10 parts by weight or more, more preferably 0.05 to 5 parts by weight, even more preferably 0.1 to 3 parts by weight, and particularly preferably 0.2 to 1 part by weight, relative to 100 parts by weight of the base polymer.

[0221] Examples of the light stabilizer include hindered amine light stabilizers and ultraviolet stabilizers.

[0222] Examples of the hindered amine light stabilizer include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate.

[0223] Examples of ultraviolet stabilizers include nickel bis(octylphenyl) sulfide, [2,2'-thiobis(4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-tert-butyl-4-hydroxybenzyl-phosphate monoethylate, nickel-dibutyldithiocarbamate, benzoate-type quenchers, and nickel-dibutyldithiocarbamate.

[0224] [Fatty acid ester] The urethane-based pressure-sensitive adhesive composition may contain a fatty acid ester as another component from the viewpoint of improving the wettability of the urethane-based pressure-sensitive adhesive layer, etc. The fatty acid ester may be one type only, or two or more types.

[0225] The content of the fatty acid ester in the urethane-based pressure-sensitive adhesive composition may be any appropriate content ratio as long as the effects of the present invention are not impaired. The content of the fatty acid ester in the urethane-based pressure-sensitive adhesive composition is preferably 0.01 to 50 parts by weight, more preferably 0.05 to 45 parts by weight, even more preferably 0.1 to 40 parts by weight, and particularly preferably 0.5 to 25 parts by weight, relative to 100 parts by weight of the base polymer.

[0226] The number-average molecular weight Mn of the fatty acid ester is preferably 200 to 400, more preferably 210 to 395, even more preferably 230 to 380, particularly preferably 240 to 360, and most preferably 250 to 350. By adjusting the number-average molecular weight Mn of the fatty acid ester within the above range, the wetting speed can be further improved. If the number-average molecular weight Mn of the fatty acid ester is too small, the wetting speed may not be improved even if a large amount is added. If the number-average molecular weight Mn of the fatty acid ester is too large, the curing properties of the adhesive during drying may be deteriorated, which may have an adverse effect not only on the wetting properties but also on other adhesive properties.

[0227] As the fatty acid ester, any appropriate fatty acid ester can be used as long as it does not impair the effects of the present invention. Examples of such fatty acid esters include polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, behenic acid monoglyceride, cetyl 2-ethylhexanoate, isopropyl myristate, isopropyl palmitate, cholesteryl isostearate, lauryl methacrylate, coconut fatty acid methyl ester, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, isotridecyl stearate, 2-ethylhexanoic acid triglyceride, butyl laurate, and octyl oleate.

[0228] 〔catalyst〕 The catalyst that can be contained in the urethane-based pressure-sensitive adhesive composition can be any appropriate catalyst as long as it does not impair the effects of the present invention. Examples of such catalysts include tertiary amine compounds and organometallic compounds. The catalyst may be one type or two or more types.

[0229] Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7(DBU).

[0230] Examples of organometallic compounds include tin-based compounds and non-tin-based compounds.

[0231] Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

[0232] Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanium, and butoxytitanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium compounds such as zirconium naphthenate.

[0233] In terms of being able to more effectively exhibit the effects of the present invention, the catalyst that can be contained in the urethane-based pressure-sensitive adhesive composition is preferably a non-tin-based compound, and more preferably an iron-based compound such as iron 2-ethylhexanoate or iron acetylacetonate.

[0234] The amount of catalyst that can be contained in the urethane-based pressure-sensitive adhesive composition is preferably 0.001% by weight to 1.0% by weight based on the total amount of the base polymer.

[0235] 〔solvent〕 The solvent that can be contained in the urethane-based pressure-sensitive adhesive composition can be any appropriate solvent as long as it does not impair the effects of the present invention. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Among these solvents, ethyl acetate and toluene are preferred.

[0236] ≪≪1-2. Base material layer≫≫ The thickness of the substrate layer may be any appropriate thickness depending on the application. The thickness of the substrate layer is preferably 5 μm to 300 μm, more preferably 10 μm to 250 μm, still more preferably 15 μm to 200 μm, and particularly preferably 20 μm to 150 μm.

[0237] The substrate layer may be a single layer or a laminate of two or more layers. The substrate layer may be stretched.

[0238] Any appropriate material can be used as the material for the substrate layer depending on the application. Examples include plastic, paper, metal film, nonwoven fabric, etc. Plastic is preferred. The substrate layer may be made of one material or two or more materials. For example, it may be made of two or more plastics.

[0239] Examples of the plastic include polyester resins, polyamide resins, and polyolefin resins. Polyester resins, such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, are preferred.

[0240] The substrate layer may contain any appropriate additives as needed. Examples of additives that may be contained in the substrate layer include antioxidants, UV 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. In particular, when the material of the substrate layer is plastic, it is preferable to contain some of the above-mentioned additives for the purpose of preventing deterioration, etc. From the viewpoint of improving weather resistance, etc., particularly preferred additives include antioxidants, UV absorbers, light stabilizers, and fillers.

[0241] 2. Surface protection film manufacturing method The surface protection film according to the embodiment of the present invention can be produced by any suitable method. (1) A method of applying a solution or a hot melt of a material for forming the adhesive layer onto a substrate layer; (2) A method similar to the above, in which an adhesive layer formed by coating on a release liner is transferred onto a substrate layer. (3) A method of forming and applying a material for forming a pressure-sensitive adhesive layer onto a substrate layer by extrusion; (4) A method of extruding a substrate layer and a pressure-sensitive adhesive layer in two or more layers. (5) A method of laminating a single layer of an adhesive layer onto a substrate layer, or a method of laminating a double layer of an adhesive layer together with a laminate layer, (6) A method of laminating a pressure-sensitive adhesive layer with a base layer-forming material such as a film or laminate layer in two or more layers. The above-mentioned manufacturing method can be carried out according to any suitable manufacturing method.

[0242] Examples of the coating method include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, die coating, and roll brush coating.

[0243] <<<<<3. Uses of Surface Protection Film>>>> The surface protection film according to the embodiment of the present invention can be used for any suitable application. Preferably, the surface protection film of the present invention causes very little contamination to the adherend and preferably has excellent wettability and reworkability, and is therefore preferably used for surface protection of, for example, optical components and electronic components. Examples of optical components include LCDs, touch panels using LCDs, color filters used in LCDs, polarizing plates, and the like.

[0244] In the case of a component to which a surface protection film according to an embodiment of the present invention is attached, such as an optical component or an electronic component, the attached surface protection film can be manually attached and peeled off many times.

[0245] That is, an optical member according to an embodiment of the present invention has the surface protection film of the present invention attached thereto, and an electronic member according to an embodiment of the present invention has the surface protection film of the present invention attached thereto. [Example]

[0246] 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.

[0247] <Adhesion to glass> The surface protection film (25 mm wide x 140 mm long) with the release liner removed was attached to glass (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) using a 2 kg hand roller in one stroke. The sample was then left at an ambient temperature of 23°C for 30 minutes. The resulting evaluation sample was measured using a tensile tester. The tensile tester used was an Autograph AG-Xplus HS 6000 mm / min High-Speed ​​Model (AG-50NX plus) manufactured by Shimadzu Corporation. After the evaluation sample was placed in the tensile tester, the tensile test was initiated. The test conditions were a peel angle of 180° and a peel speed (pulling speed) of 300 mm / min. The load applied when peeling the surface protection film from the glass was measured, and the average load was used as the adhesive strength (peel force) of the surface protection film to glass.

[0248] <Glass peeling electrification voltage> The surface protection film with the release liner removed was cut to a size of 70 mm wide and 100 mm long and pressed onto the surface of glass (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a hand roller, so that one end of the surface protection film protruded 30 mm beyond the edge of the adherend. This sample was left for one day in an environment of 23°C and 50% RH and then set in a predetermined position on a sample fixing table with a height of 20 mm. The end of the surface protection film protruding 30 mm from the adherend was fixed to an automatic winder (not shown), and the film was peeled at a peel angle of 150° and a peel rate of 30 m / min. The potential generated on the adherend surface during this process was measured as the "peeling electrification voltage" using a potential meter (manufactured by Shishido Electrostatics Co., Ltd., model "STATIRON DZ-4") fixed 30 mm above the center of the adherend. Measurements were performed in an environment of 23°C and 50% RH.

[0249] <Haze> The urethane-based pressure-sensitive adhesive composition was coated on the release-treated surface of a 75 μm-thick polyester film (trade name: Diafoil MRF75, manufactured by Mitsubishi Chemical Corporation) with one side treated for release with silicone, and dried under the conditions of Examples and Comparative Examples to prepare a urethane-based pressure-sensitive adhesive layer. Next, the surface of the urethane-based pressure-sensitive adhesive layer was covered with a 75 μm-thick polyester film (trade name: Diafoil MRE75, manufactured by Mitsubishi Chemical Corporation) with one side treated for release with silicone, with the release-treated surface of the polyester film facing the urethane-based pressure-sensitive adhesive layer, and the resulting mixture was aged at room temperature for 5 days. Two pieces of 50 mm x 50 mm cardboard with a 20 mm x 20 mm hole punched in the center were prepared, and the sample was attached to one of them using a hand roller with one stroke, and then the other was attached. The haze of the evaluation sample obtained as described above was measured using "HM-150N" manufactured by Murakami Color Research Laboratory.

[0250] <Glue residue evaluation> The release liner was peeled off from the surface protection film (25 mm wide x 140 mm long), and the adhesive side of the film was cut 1 cm into the center with a cutter blade at 30 degrees. When glue residue was visually confirmed, it was marked with an X, and when no glue residue was confirmed, it was marked with an ◯.

[0251] <Black dot rating> After peeling off the release liner, the surface protection film was visually inspected for the number of black spots (glue depressions) per 10 cm square.

[0252] <Proportion of hydroxyl groups contained in urethane-based pressure-sensitive adhesive composition> It was calculated from the following formula based on the hydroxyl value (OHV) of 100 g of the total base polymer contained in the urethane-based pressure-sensitive adhesive composition and the molecular weight of KOH (56.1). OHV[mgKOH / g] / 56.1[mg / mmol]=OH[mmol / g]

[0253] [Production Example 1]: Production of a solution of urethane prepolymer A 333 g of polytetramethylene glycol (product name "PTMG3000", manufactured by Mitsubishi Chemical Corporation), 83 g of polypropylene glycol (product name "Sannyx GP-1500", manufactured by Sanyo Chemical Industries, Ltd.), and 110 g of ethyl acetate (manufactured by Tosoh Corporation) as a solvent were added to a polymerization experimental apparatus equipped with a 1 L round-bottom separable flask, a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade. While stirring, 0.041 g of dibutyltin(IV) dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst was added, and the mixture was purged with nitrogen at room temperature for 1 hour. Then, under nitrogen flow and stirring, 13.0 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the solution temperature in the experimental apparatus was controlled to 90±2°C using a water bath, and the temperature was maintained for 4 hours to obtain a solution of urethane prepolymer A. During the polymerization, ethyl acetate was added dropwise as needed to control the temperature during polymerization and to prevent a decrease in stirrability due to increased viscosity. The total amount of ethyl acetate added was 320 g. The solids concentration of the urethane prepolymer A solution was 50 wt%.

[0254] [Production Example 2]: Production of urethane prepolymer B solution A polymerization experiment apparatus equipped with a 1 L round-bottom separable flask, a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade was charged with 197 g of polypropylene glycol (product name "Sannyx PP-2000", manufactured by Sanyo Chemical Industries, Ltd.), 197 g of polyester polyol (product name "Kuraray Polyol P-2010", manufactured by Kuraray Co., Ltd.), 110 g of toluene (manufactured by Tosoh Corporation) as a solvent, and 0.041 g of dibutyltin(IV) dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst, and the atmosphere was replaced with nitrogen at room temperature for 1 hour while stirring. Then, under nitrogen flow and stirring, 33.5 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the solution temperature in the experimental apparatus was maintained at 90±2°C using a water bath. This was maintained for 4 hours, after which 44 g of polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Industries, Ltd.) was added, and the solution temperature in the experimental apparatus was maintained at 90±2°C using a water bath. This was maintained for 2 hours, after which 25.4 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the solution temperature in the experimental apparatus was maintained at 90±2°C using a water bath. This maintained for 2 hours, yielding a solution of urethane prepolymer B. During the polymerization, toluene was added dropwise as needed to control the temperature and prevent a decrease in stirrability due to increased viscosity. The total amount of toluene added was 380 g. The solids concentration of the urethane prepolymer B solution was 50 wt%.

[0255] Example 1 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-571 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (1). The film was aged at room temperature for 5 days and then evaluated.

[0256] Example 2 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer B, 2.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-571 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (2). The film was aged at room temperature for 5 days and then evaluated.

[0257] Example 3 95 parts by weight of urethane prepolymer B, 3 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 2 parts by weight of PTGL3000 (Hodogaya Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 3.7 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, 0.03 parts by weight of Nursem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (3). The film was then aged at room temperature for 5 days and evaluated.

[0258] Example 4 95 parts by weight of urethane prepolymer A, 3.5 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 1.5 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 3.8 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (4). The film was then aged at room temperature for 5 days and evaluated.

[0259] Example 5 95 parts by weight of urethane prepolymer A, 3 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 3.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (5). The film was then aged at room temperature for 5 days and evaluated.

[0260] Example 6 80 parts by weight of urethane prepolymer A, 12 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 8 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 6.0 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based adhesive solution. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (6). The film was then aged at room temperature for 5 days and evaluated.

[0261] Example 7 60 parts by weight of urethane prepolymer A, 28 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 12 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 8.0 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based adhesive solution. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (7). The film was then aged at room temperature for 5 days and evaluated.

[0262] Example 8 60 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 8.6 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (8). The film was then aged at room temperature for 5 days and evaluated.

[0263] Example 9 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP4000 (Sanyo Chemical Co., Ltd., Mn = 4000) as a polyol having three hydroxyl groups, 8.7 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based adhesive solution. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (9). The film was then aged at room temperature for 5 days and evaluated.

[0264] Example 10 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-563 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (10). The film was aged at room temperature for 5 days and then evaluated.

[0265] Example 11 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer B, 2.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-563 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (11). The film was aged at room temperature for 5 days and then evaluated.

[0266] Example 12 A urethane prepolymer B solution was prepared by diluting 95 parts by weight of urethane prepolymer B, 3 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 2 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 3.7 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-563 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight, to obtain a urethane adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (12). The film was then aged at room temperature for 5 days and evaluated.

[0267] Example 13 95 parts by weight of urethane prepolymer A, 3.5 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 1.5 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 3.8 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-563 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (13). The film was then aged at room temperature for 5 days and evaluated.

[0268] Example 14 95 parts by weight of urethane prepolymer A, 3 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 3.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-563 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based adhesive solution. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (14). The film was then aged at room temperature for 5 days and evaluated.

[0269] Example 15 80 parts by weight of urethane prepolymer A, 12 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 8 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 6.0 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-563 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (15). The film was then aged at room temperature for 5 days and evaluated.

[0270] Example 16 A urethane prepolymer A solution was prepared using 60 parts by weight of urethane prepolymer A, 28 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 12 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 8.0 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-563 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst. The mixture was diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (16). The film was then aged at room temperature for 5 days and evaluated.

[0271] Example 17 60 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 8.6 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-563 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based adhesive solution. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (17). The film was then aged at room temperature for 5 days and evaluated.

[0272] Example 18 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP4000 (Sanyo Chemical Co., Ltd., Mn = 4000) as a polyol having three hydroxyl groups, 8.7 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-563 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, 0.03 parts by weight of Narsem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (18). The film was then aged at room temperature for 5 days and evaluated.

[0273] Example 19 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (19). The film was aged at room temperature for 5 days and then evaluated.

[0274] Example 20 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer B, 2.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (20). The film was aged at room temperature for 5 days and then evaluated.

[0275] Example 21 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-556 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (21). The film was aged at room temperature for 5 days and then evaluated.

[0276] Example 22 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer B, 2.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of the fluorine-based oligomer Megafac F-556 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (22). The film was aged at room temperature for 5 days and then evaluated.

[0277] Example 23 A urethane adhesive solution was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of the fluorine-based oligomer Megafac F-571 (manufactured by DIC Corporation), 0.05 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (23). The film was then aged at room temperature for 5 days and evaluated.

[0278] Example 24 A urethane adhesive solution was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of the fluorine-based oligomer Megafac F-571 (manufactured by DIC Corporation), 0.10 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (24). The film was then aged at room temperature for 5 days and evaluated.

[0279] Example 25 A urethane adhesive solution was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of the fluorine-based oligomer Megafac F-571 (manufactured by DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (25). The film was then aged at room temperature for 5 days and evaluated.

[0280] Example 26 A urethane adhesive solution was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of the fluorine-based oligomer Megafac F-571 (manufactured by DIC Corporation), 1.00 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (26). The film was then aged at room temperature for 5 days and evaluated.

[0281] Example 27 A urethane adhesive solution was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of the fluorine-based oligomer Megafac F-563 (manufactured by DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (27). The film was then aged at room temperature for 5 days and evaluated.

[0282] Example 28 A urethane adhesive solution was obtained by diluting with 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of the fluorine-based oligomer Megafac F-477 (manufactured by DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (28). The film was then aged at room temperature for 5 days and evaluated.

[0283] Example 29 A urethane adhesive solution was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of the fluorine-based oligomer Megafac F-556 (manufactured by DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (29). The film was then aged at room temperature for 5 days and evaluated.

[0284] Example 30 The mixture contained 95 parts by weight of urethane prepolymer A, 3.5 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000) as a polyol having three hydroxyl groups, 1.5 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000) as a polyol having three hydroxyl groups, 3.8 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, and Megafa, a fluorine-based oligomer. A urethane adhesive solution was prepared by diluting a mixture of 0.5 parts by weight of BASF F-571 (DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric (Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (30). The film was aged at room temperature for 5 days and then evaluated.

[0285] Example 31 The mixture contained 95 parts by weight of urethane prepolymer A, 3 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000) as a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000) as a polyol having three hydroxyl groups, 3.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, and Megafac, a fluorine-based oligomer. A urethane adhesive solution was prepared by diluting 0.5 parts by weight of F-571 (DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric salt (Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S", 75 μm thick, Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (31). The film was aged at room temperature for 5 days and then evaluated.

[0286] Example 32 The composition contained 80 parts by weight of urethane prepolymer A, 12 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000) as a polyol having three hydroxyl groups, 8 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000) as a polyol having three hydroxyl groups, 6.0 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, and Megafac, a fluorine-based oligomer. A urethane adhesive solution was prepared by diluting 0.5 parts by weight of F-571 (DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric salt (Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S", 75 μm thick, Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (32). The film was aged at room temperature for 5 days and then evaluated.

[0287] Example 33 The mixture contained 60 parts by weight of urethane prepolymer A, 28 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000) as a polyol having three hydroxyl groups, 12 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000) as a polyol having three hydroxyl groups, 8.0 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, and Megafa, a fluorine-based oligomer. A urethane adhesive solution was prepared by diluting 0.5 parts by weight of F-571 (DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S", 75 μm thick, Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (33). The film was aged at room temperature for 5 days and then evaluated.

[0288] Example 34 The mixture contained 60 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000) as a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000) as a polyol having three hydroxyl groups, 8.6 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, and Megafa, a fluorine-based oligomer. A urethane adhesive solution was prepared by diluting 0.5 parts by weight of F-571 (DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S", 75 μm thick, Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (34). The film was aged at room temperature for 5 days and then evaluated.

[0289] Example 35 The mixture contained 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000) as a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP4000 (manufactured by Sanyo Chemical Co., Ltd., Mn=4000) as a polyol having three hydroxyl groups, 8.7 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, and Megafa, a fluorine-based oligomer. A urethane adhesive solution was prepared by diluting 0.5 parts by weight of F-571 (DIC Corporation), 0.50 parts by weight of 1-ethyl-3-methylimidazolium tri(fluoromethanesulfonyl)imide (AS110, Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant, and 0.03 parts by weight of Nursem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S", 75 μm thick, Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (35). The film was aged at room temperature for 5 days and then evaluated.

[0290] Comparative Example 1 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem ferric oxide (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C1). The film was aged at room temperature for 5 days and then evaluated.

[0291] Comparative Example 2 A urethane-based adhesive solution was prepared by diluting 100 parts by weight of urethane prepolymer B, 2.9 parts by weight of an isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinker, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narcem Ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate to a total solids content of 50% by weight. The urethane-based adhesive solution was then applied to a polyester resin substrate (trade name "T100-75S," 75 μm thick, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at 130°C for 3 minutes to prepare an adhesive layer composed of the adhesive composition. Next, the silicone-treated surface of a 25 μm thick polyester resin release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C2). The film was aged at room temperature for 5 days and then evaluated.

[0292] Comparative Example 3 50 parts by weight of urethane prepolymer A, 35 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 9.2 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Nursem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (C3). The film was then aged at room temperature for 5 days and evaluated.

[0293] Comparative Example 4 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (Asahi Glass Co., Ltd., Mn = 10000) as a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (Sanyo Chemical Co., Ltd., Mn = 3000) as a polyol having three hydroxyl groups, 10.1 parts by weight of an isocyanate compound (Coronate HX:C / HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of fluorine-based oligomer Megafac F-571 (DIC Corporation), 0.5 parts by weight of Irganox 1010 (BASF Corporation) as an antioxidant, 0.03 parts by weight of Nursem ferric iron (Nippon Chemical Industry Co., Ltd.) as a catalyst, diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane adhesive solution. The urethane adhesive solution was then applied to a polyester resin substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a dry thickness of 75 μm, and cured and dried at a drying temperature of 130°C for 3 minutes to produce an adhesive layer made of the adhesive composition. The silicone-treated surface of a 25 μm thick release liner made of polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side silicone-treated was then bonded to the surface of the resulting adhesive layer to obtain a surface protection film (C4). The film was then aged at room temperature for 5 days and evaluated.

[0294] Examples 36 to 70 The release liner was peeled off from each of the surface protection films obtained in Examples 1 to 35, and the film was attached to a polarizing plate (manufactured by Nitto Denko Corporation, product name "TEG1465DUHC"), which is an optical component, to obtain an optical component with the surface protection film attached.

[0295] Examples 71 to 105 The release liner was peeled off from each of the surface protection films obtained in Examples 1 to 35, and the film was attached to a conductive film (manufactured by Nitto Denko Corporation, product name "ELECRYSTA V270L-TFMP"), which is an electronic component, to obtain an electronic component with the surface protection film attached.

[0296] [Table 1] [Table 2] [Table 3] [Industrial Applicability]

[0297] The surface protective film of the present invention can be used for any suitable application, and is preferably used for protecting the surfaces of optical members and electronic members. [Explanation of symbols]

[0298] 1 Base material layer 2. Adhesive layer 10 Surface protection film

Claims

1. A surface protection film including a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is composed of a urethane-based pressure-sensitive adhesive formed from a urethane-based pressure-sensitive adhesive composition, The urethane-based pressure-sensitive adhesive composition contains a base polymer and a fluorine-based compound, the content of the base polymer in the urethane-based pressure-sensitive adhesive composition is 70% by weight to 99.99% by weight, the base polymer comprises a urethane prepolymer; The base polymer contains a polyoxyalkylene structure represented by general formula (1), the base polymer comprises a polyol, and the polyol is not a urethane prepolymer; the urethane-based pressure-sensitive adhesive composition contains the urethane prepolymer and the polyol in a weight ratio of urethane prepolymer:polyol of 70:30 to 95:5; the proportion of hydroxyl groups contained in the urethane-based pressure-sensitive adhesive composition is less than 30 mmol per 100 g of the base polymer; the fluorine-based compound has a surface tension of 23 mN / m or more when dissolved in a 0.1% propylene glycol monomethyl ether solution; Surface protection film. 【Chemical 1】 (In general formula (1), R 1 represents one type selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms. Multiple R 1 s may be the same or different from one another. n represents an integer of 1 to 4. m represents an integer of 1 to 200.)

2. The surface protective film according to claim 1 , wherein the urethane prepolymer contains a polyoxyalkylene structure represented by the general formula (1).

3. The surface protective film according to claim 1 or 2, wherein the polyol contains a polyoxyalkylene structure represented by general formula (1): 【Chemistry 2】 (In general formula (1), R 1 represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a hydroxyalkyl group having 1 to 6 carbon atoms. 1 may be the same or different from each other. n represents an integer of 1 to 4. m represents an integer of 1 to 200.

4. The surface protection film according to claim 1 , wherein the pressure-sensitive adhesive layer has a haze of 3.5% or less.

5. 5. The surface protection film according to claim 1, wherein the urethane-based pressure-sensitive adhesive composition comprises 0.05 parts by weight or more of an ionic compound relative to 100 parts by weight of the base polymer.

6. An optical member having the surface protective film according to any one of claims 1 to 5 attached thereto.

7. An electronic component having the surface protection film according to any one of claims 1 to 5 attached thereto.

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