Surface protection film

Abstract

To provide a surface protection film including a urethane-based pressure-sensitive adhesive layer having an excellent surface modulus.SOLUTION: A surface protection film includes a urethane-based pressure-sensitive adhesive layer formed from a urethane-based pressure-sensitive adhesive composition. The composition typically comprises a urethane prepolymer, a polyol, and a polyfunctional isocyanate compound, the urethane prepolymer and / or the polyol having a constituent unit represented by formula (1). The urethane-based pressure-sensitive adhesive layer has a surface modulus of 0.8 MPa or greater.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A surface protection film is attached to an optical member or an electronic member in order to prevent the surface from being damaged during processing, assembly, inspection, transportation, etc. When the need for surface protection no longer exists, such a surface protection film is peeled off from the optical member or the electronic member (Patent Document 1).

[0003] As the adhesive layer included in such a surface protection film, an adhesive layer composed of various adhesives is known. In terms of excellent reworkability, wettability, and transparency, as the adhesive layer included in the surface protection film attached to an optical member or an electronic member, a urethane-based adhesive layer composed of a urethane-based adhesive is preferably adopted.

[0004] However, in a urethane-based adhesive layer composed of a urethane-based adhesive, the surface elastic modulus tends to be smaller than that of an adhesive layer composed of other adhesives. Therefore, there are cases where the surface protection film cannot sufficiently relieve the stress applied from the outside and cannot sufficiently reduce the damage to the adherend. Therefore, an improvement in the surface elastic modulus in the urethane-based adhesive layer is desired.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a surface protection film including a urethane-based adhesive layer excellent in surface elastic modulus.

Means for Solving the Problems

[0007] The surface protection film according to an embodiment of the present invention is a surface protection film including a urethane-based adhesive layer, the urethane-based adhesive layer is composed of a urethane-based adhesive formed from a urethane-based adhesive composition, the urethane-based adhesive composition (A) includes a urethane prepolymer, a polyol, and a polyfunctional isocyanate compound, and the urethane prepolymer and / or the polyol has a structural unit represented by the following general formula (1), or (B) includes a urethane prepolymer having a structural unit represented by the following general formula (1) and a polyfunctional isocyanate compound, or (C) includes a polyol having a structural unit represented by the following general formula (1) and a polyfunctional isocyanate compound, the surface elastic modulus of the urethane-based adhesive layer is 0.8 MPa or more, Surface protection film. [Chemical formula] (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. A plurality of R 1 may be the same as each other or different from each other. n represents an integer of 1 to 4. m is the number of repetitions of the structural unit and represents an integer of 1 to 200.)

[0008] In one embodiment, the urethane prepolymer and / or the polyol has a structural unit represented by the following general formula (2), and the content ratio of the structural unit represented by the general formula (1) in the urethane-based adhesive composition is larger than the content ratio of the structural unit represented by the following general formula (2). [Chemical formula] (In general formula (2), R 2represents one selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms. A plurality of Rs 2 may be the same as or different from each other. p is the number of repetitions of the structural unit and represents an integer of 1 to 300.)

[0009] In one embodiment, the urethane-based pressure-sensitive adhesive composition contains an ionic compound, and the content ratio of the ionic compound with respect to 100 parts by weight in total of the urethane prepolymer and the polyol is 0.05 part by weight or more.

[0010] In one embodiment, the urethane-based pressure-sensitive adhesive composition contains at least one selected from the group consisting of a fluorine-based additive and a silicone-based additive, and the content ratio of the total amount of the fluorine-based additive and the silicone-based additive with respect to 100 parts by weight in total of the urethane prepolymer and the polyol is 0.01 part by weight or more.

[0011] In one embodiment, when the urethane-based pressure-sensitive adhesive layer is bonded to a glass plate and peeled at a peeling angle of 180 degrees and a peeling speed of 300 mm / min after 30 minutes at 23°C, the peeling force is 0.5 gf / 25 mm to 2.0 gf / 25 mm.

[0012] In one embodiment, the haze of the urethane-based pressure-sensitive adhesive layer is 3.5% or less.

[0013] In one embodiment, when the urethane-based pressure-sensitive adhesive layer is bonded to a glass plate and peeled at a peeling angle of 180 degrees and a peeling speed of 0.3 m / min after 24 hours at 23°C, the residual adhesion rate to the glass plate is 80% or more.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a surface protection film including a urethane-based pressure-sensitive adhesive layer having an excellent surface elastic modulus.

Brief Description of the Drawings

[0015]

Figure 1

Embodiments for Carrying Out the Invention

[0016] ≪≪1. Surface protection film≫≫ The surface protection film according to the embodiment of the present invention includes a urethane-based adhesive layer. On the adhesive surface side of the urethane-based adhesive layer, an optional appropriate release liner having releasability may be laminated within a range that does not impair the effects of the present invention.

[0017] The surface protection film according to the embodiment of the present invention preferably has a base material layer and a urethane-based adhesive layer. The base material layer may be only one layer or two or more layers. The urethane-based adhesive layer may be only one layer or two or more layers. The surface protection film of the present invention may have any appropriate other layer within a range that does not impair the effects of the present invention, in addition to the base material layer and the urethane-based adhesive layer.

[0018] FIG. 1 is a schematic cross-sectional view of a surface protection film according to a preferred embodiment of the present invention. The surface protection film 10 includes a base material layer 1 and an adhesive layer 2. The surface protection film of the present invention may further have any appropriate other layer as needed, such as a release liner (not shown).

[0019] For the surface of the base material layer 1 where the adhesive layer 2 is not attached, for the purpose of forming a winding body that can be easily rewound, for example, fatty acid amide, polyethyleneimine, long-chain alkyl-based additives, etc. may be added to the base material layer for release treatment, or a coating layer made of any appropriate release agent such as silicone-based, long-chain alkyl-based, fluorine-based, etc. may be provided.

[0020] Examples of the release liner that can be provided on the adhesive surface side of the urethane-based adhesive layer include a release liner in which the surface of a base material (liner base material) such as paper or a plastic film is silicone-treated, and a release liner in which the surface of a base material (liner base material) such as paper or a plastic film is laminated with a polyolefin-based resin.

[0021] Examples of the plastic film as the base material included in the release liner include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, and the like.

[0022] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, still more preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0023] The thickness of the surface protection film according to the embodiment of the present invention can be set to any appropriate thickness according to the application. The thickness of the surface protection film is preferably 10 μm to 300 μm, more preferably 15 μm to 250 μm, still more preferably 20 μm to 200 μm, and particularly preferably 25 μm to 150 μm.

[0024] In the surface protection film according to the embodiment of the present invention, the surface elastic modulus of the urethane-based adhesive layer can be improved. Therefore, the surface elastic modulus of the urethane-based adhesive layer included in the surface protection film of the present invention is typically 0.8 MPa or more, preferably 1.2 MPa or more, more preferably 1.5 MPa or more, still more preferably 2.0 MPa or more, and particularly preferably 2.5 MPa or more, and is, for example, 4.0 MPa or less. If the surface elastic modulus of the urethane-based adhesive layer is equal to or higher than the above lower limit, the surface protection film according to the embodiment of the present invention can exhibit excellent surface protection properties. Note that the surface elastic modulus of the urethane-based adhesive layer can be measured in accordance with ISO14577.

[0025] When protecting an adherend having a step with the surface protection film, there may be a case where thickening is required so as to follow the step. The surface protection film according to the embodiment of the present invention enables thickening of the urethane-based adhesive layer. Therefore, as the lower limit value of the thickness of the urethane-based adhesive layer included in the surface protection film of the present invention, preferably it is 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, still more preferably 20 μm or more, still more preferably 30 μm or more, still more preferably 40 μm or more, still more preferably 50 μm or more, particularly preferably 60 μm or more, and most preferably 65 μm or more. If the urethane-based adhesive layer can be thickened in this way, the surface protection film according to the embodiment of the present invention can follow the step well when protecting a display with a large step, such as an organic EL display. Note that as the upper limit value of the thickness of the urethane-based adhesive layer, typically it is 150 μm or less. The upper limit value of the thickness of the urethane-based adhesive layer can be appropriately changed according to the application, and for example, it can also be 100 μm or less.

[0026] When the surface protection film is no longer required to protect the surface of the adherend, there may be a case where easy peelability, which enables smooth peeling from the adherend, is required. The surface protection film according to the embodiment of the present invention can exhibit easy peelability. When the surface protection film of the present invention laminates the urethane-based adhesive layer it contains on a glass plate and peels it at a peeling angle of 180 degrees and a peeling speed of 300 mm / min after 30 minutes at 23°C, the peeling force is 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, still 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. If the peeling force is within the above range, the surface protection film according to the embodiment of the present invention can exhibit excellent easy peelability.

[0027] In some cases, a surface protection film is required to have transparency (low haze) that enables inspection of the adherend when it is attached to the adherend. The surface protection film according to an embodiment of the present invention can achieve low haze. In the surface protection film of the present invention, the haze of the urethane-based adhesive layer it contains is preferably 4.5% or less, more preferably 4.0% or less, still more preferably 3.5% or less, particularly preferably 3.0% or less, and most preferably 2.5% 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.

[0028] In some cases, a surface protection film is required to reduce the adhesive residue property in which the adhesive remains on the adherend when peeled from the adherend. For the surface protection film according to an embodiment of the present invention, after laminating the urethane-based adhesive layer it contains to a glass plate and peeling it from the glass plate at a peeling angle of 180 degrees and a peeling speed of 0.3 m / min after 24 hours at 23°C, the residual adhesion rate to the glass plate is preferably 60% or more, more preferably 70% or more, still more preferably 80% or more, particularly preferably 85% or more, and most preferably 90% or more. If the residual adhesion rate is within the above range, the surface protection film according to the embodiment of the present invention can reduce the adhesive residue property.

[0029] In some cases, a surface protection film is required to suppress charging when peeling from the adherend from the viewpoint of reducing damage to the adherend. For the surface protection film according to an embodiment of the present invention, when peeling the urethane-based adhesive layer it contains from a glass plate at a peeling angle of 150 degrees and a peeling speed of 30 m / min after 24 hours at 23°C, the peeling charging voltage is preferably 15 kV or less, more preferably 10 kV or less, still more preferably 5 kV or less, particularly preferably 2 kV or less, and most preferably 1 kV or less. If the peeling charging voltage is within the above range, the surface protection film according to the embodiment of the present invention can effectively prevent charging during peeling.

[0030] ≪1-1. Urethane-based pressure-sensitive adhesive layer≫ The urethane-based pressure-sensitive adhesive layer is composed of a urethane-based pressure-sensitive adhesive 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 to become the pressure-sensitive adhesive layer.

[0031] The urethane-based pressure-sensitive adhesive can be defined as being formed from a urethane-based pressure-sensitive adhesive composition. This is because the urethane-based pressure-sensitive adhesive cannot be directly specified by its structure since the urethane-based pressure-sensitive adhesive composition undergoes a cross-linking reaction or the like by heating or ultraviolet irradiation to become the urethane-based pressure-sensitive adhesive, and there is a situation (an "impossible and impractical situation") that it is approximately not practical. Therefore, by defining it as "formed from a urethane-based pressure-sensitive adhesive composition", the urethane-based pressure-sensitive adhesive is appropriately specified as a "substance".

[0032] As a method for forming the urethane-based pressure-sensitive adhesive layer, any appropriate forming method can be adopted as long as the effects of the present invention are not impaired. Such forming methods include, for example, a method (direct method) of directly applying a urethane-based pressure-sensitive adhesive composition to an arbitrary appropriate base film (for example, the base material layer in the surface protection film according to the embodiment of the present invention) and drying or curing it, and a method (transfer method) of applying a urethane-based pressure-sensitive adhesive composition to the surface (release surface) of a release liner, drying or curing it to form a urethane-based pressure-sensitive adhesive layer on the surface, and then laminating the urethane-based pressure-sensitive adhesive layer to a base film (for example, the base material layer in the surface protection film according to the embodiment of the present invention) to transfer the urethane-based pressure-sensitive adhesive layer. From the viewpoint of the anchoring property of the pressure-sensitive adhesive layer, typically, the direct method can be preferably adopted.

[0033] As such a method for applying (typically coating) the urethane-based pressure-sensitive adhesive layer, for example, various conventionally known methods such as roll coating method, gravure coating method, reverse coating method, kiss coating method, dip roll coating method, bar coating method, roll brush coating method, spray coating method, knife coating method, air knife coating method, spray coating method, comma coating method, direct coating method, coating method using a die coater, etc. can be appropriately adopted.

[0034] The drying of the urethane-based pressure-sensitive adhesive composition can be carried out under heating as necessary (for example, by heating to about 60°C to 150°C). As means for curing the urethane-based pressure-sensitive adhesive composition, for example, ultraviolet rays, laser beams, α-rays, β-rays, γ-rays, X-rays, and electron beams can be appropriately employed.

[0035] The urethane-based pressure-sensitive adhesive composition (A) contains a urethane prepolymer, a polyol, and a polyfunctional isocyanate compound, and the urethane prepolymer and / or the polyol has a structural unit represented by the following general formula (1), or (B) contains a urethane prepolymer having a structural unit represented by the following general formula (1) and a polyfunctional isocyanate compound, or (C) contains a polyol having a structural unit represented by the following general formula (1) and a polyfunctional isocyanate compound. [Chemical formula] (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. A plurality of R 1 may be the same as or different from each other. n represents an integer of 1 to 4. m is the number of repetitions of the structural unit and represents an integer of 1 to 200.) Since the urethane-based pressure-sensitive adhesive is formed from a urethane-based pressure-sensitive adhesive composition containing a urethane prepolymer having a structural unit represented by the above general formula (1) and / or a polyol, the surface elastic modulus of the urethane-based pressure-sensitive adhesive layer can be sufficiently improved.

[0036] In this specification, the "urethane prepolymer" is the "urethane prepolymer" generally referred to by those skilled in the art in the production of urethane resins and is different from the "polyol". In other words, the "polyol" does not include urethane prepolymers (typically polyurethane polyols).

[0037] In general formula (1), R 1 Examples of the alkyl group represented by [R] include linear alkyl groups such as methyl group, ethyl group, n-propyl group, etc.; branched alkyl groups such as isopropyl group, isobutyl group, 2-ethylhexyl group, etc.

[0038] In general formula (1), R 1 Examples of the hydroxyalkyl group represented by [R] include hydroxymethyl group, 2-hydroxyethyl group, 2-methyl-1,4-hydroxybutyl group, etc.

[0039] Among [R] in general formula (1), preferably, the above alkyl group and hydrogen atom are mentioned, and more preferably, methyl group and hydrogen atom are mentioned. 1 Among [R] in general formula (1), preferably, the above alkyl group and hydrogen atom are mentioned, and more preferably, methyl group and hydrogen atom are mentioned.

[0040] In general formula (1), n is preferably 1 to 3, more preferably 1 or 2, and still more preferably 2.

[0041] In general formula (1), m is preferably 10 to 100, more preferably 15 to 75, and still more preferably 20 to 50.

[0042] Further, the above urethane prepolymer and / or the above polyol preferably have a structural unit (polyoxyalkylene unit) represented by the following general formula (2). More specifically, when the urethane adhesive composition is in the above aspect (A), preferably, the urethane prepolymer contains a structural unit (polyoxyalkylene unit) represented by the following general formula (2), and / or the polyol contains a polyol having a structural unit (polyoxyalkylene unit) represented by the following general formula (2). Also, when the urethane adhesive composition is in the above aspect (B), the urethane prepolymer preferably has a structural unit (polyoxyalkylene unit) represented by the following general formula (2). Further, when the urethane-based pressure-sensitive adhesive composition is in the above-described aspect (C), the polyol preferably includes a polyol having a structural unit (polyoxyalkylene unit) represented by the following general formula (2). [Chemical Formula] (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. A plurality of R 2 may be the same as or different from each other. p is the number of repetitions of the structural unit and represents an integer of 1 to 300.)

[0043] In general formula (2), examples of the alkyl group represented by R 2 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.

[0044] In general formula (2), p is preferably 10 to 250, more preferably 20 to 200, and even more preferably 30 to 150.

[0045] The content ratio of the structural unit represented by the above general formula (1) in such a urethane-based pressure-sensitive adhesive composition is, for example, 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more, for example, 100% by weight or less, and preferably 80% by weight or less.

[0046] The content ratio of the structural unit represented by the above general formula (1) in the urethane-based pressure-sensitive adhesive composition is greater than the content ratio of the structural unit represented by the above general formula (2). The ratio of the structural unit represented by the above general formula (1) to the total of the structural unit represented by the above general formula (1) and the structural unit represented by the above general formula (2) is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 65% by weight or more, for example, 100% by weight or less, and preferably 80% by weight or less. If the proportion of the structural unit represented by the general formula (1) is equal to or higher than the above lower limit, the surface elastic modulus of the urethane-based adhesive layer can be stably improved.

[0047] <1-1-A. Embodiment in which the urethane-based adhesive composition contains a urethane prepolymer, a polyol, and a polyfunctional isocyanate compound> In the embodiment of (A) above, the urethane-based adhesive is a urethane-based adhesive produced by the prepolymer method, and is formed from a urethane-based adhesive composition containing a urethane prepolymer, a polyol, and a polyfunctional isocyanate compound. The urethane-based adhesive layer composed of such a urethane-based adhesive produced by the prepolymer method can be made into a thick film, and for example, when protecting a display with a large step such as an organic EL display, it can follow the step well. More specifically, the urethane-based adhesive is formed by curing a urethane-based adhesive composition containing a urethane prepolymer, a polyol, and a polyfunctional isocyanate compound. The urethane prepolymer and the polyol preferably react with the polyfunctional isocyanate compound to form a urethane resin.

[0048] As described above, in the embodiment of (A), the urethane prepolymer and / or the polyol has the structural unit represented by the general formula (1). Preferably, at least the urethane prepolymer has the structural unit represented by the general formula (1), and more preferably both the urethane prepolymer and the polyol have the structural unit represented by the general formula (1). When the urethane prepolymer has the structural unit represented by the general formula (1), the surface elastic modulus of the urethane-based adhesive layer can be stably improved as compared with the embodiment in which only the polyol has the structural unit represented by the general formula (1). Since the urethane prepolymer and / or the polyol has the structural unit represented by the general formula (1) in this way, the urethane resin formed by the urethane reaction of the urethane prepolymer and the polyol with the polyfunctional isocyanate compound contains a structural unit derived from the structural unit represented by the general formula (1) (hereinafter referred to as the general formula (1)-derived structural unit). When the structural unit represented by the general formula (1) contains a hydrogen atom and / or an alkyl group as R 1 the hydrogen atom and / or the alkyl group is not involved in the urethane reaction and is included in the structural unit derived from the general formula (1). When the structural unit represented by the general formula (1) contains a hydroxyalkyl group as R 1 the hydroxyalkyl group may not be involved in the urethane reaction and may be included in the structural unit derived from the general formula (1), or may form a crosslinked structure by bonding to a functional group included in another structural unit (for example, a crosslinked structure (intramolecular bond or intermolecular bond) containing a urethane bond formed by the reaction of the hydroxyl group of the hydroxyalkyl group and the isocyanate group of a polyfunctional isocyanate compound). The content ratio of the structural unit derived from the general formula (1) in the urethane resin is, for example, 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more, for example, 100% by weight or less, preferably 80% by weight or less. The content ratio of the structural unit is 1 measurable by H-NMR 13 and 13C-NMR.

[0049] Also, as described above, in the aspect of (A), since the urethane prepolymer and / or the polyol preferably have the structural unit represented by the general formula (2), the urethane resin contains the structural unit represented by the general formula (2). When the structural unit represented by the general formula (2) contains a hydrogen atom and / or an alkyl group as R 2 the hydrogen atom and / or the alkyl group does not react in the urethane reaction. The content ratio of the structural unit represented by the general formula (2) in the urethane resin is, for example, 10% by weight or more, preferably 15% by weight or more, more preferably 20% by weight or more, for example, 50% by weight or less, preferably 40% by weight or less. The proportion of the structural unit derived from the general formula (1) with respect to the total of the structural unit derived from the general formula (1) and the structural unit shown in the general formula (2) exceeds, for example, 50% by weight, preferably 55% by weight or more, more preferably 60% by weight or more, for example 100% by weight or less, preferably 80% by weight or less. If the proportion of the structural unit shown in the structural unit derived from the general formula (1) is at least the above lower limit, the surface elastic modulus of the urethane-based adhesive layer can be more stably improved.

[0050] The weight ratio of the total amount of the urethane prepolymer, the polyol, and the polyfunctional isocyanate compound in the urethane-based adhesive composition is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, still more preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably 98% by weight to 100% by weight. By adjusting the weight ratio of the total amount of the urethane prepolymer and the polyol in the urethane-based adhesive composition within the above range, the surface protection film of the present invention can effectively exhibit the effects of the present invention.

[0051] The weight ratio of the urethane prepolymer to the polyol in the urethane-based adhesive composition is preferably urethane prepolymer: polyol = (50 to 100): (0 to 50), more preferably (50 to 99): (1 to 50), still more preferably (50 to 90): (10 to 50), particularly preferably (50 to 80): (20 to 50), and most preferably (50 to 70): (30 to 50). By adjusting the weight ratio of the urethane prepolymer to the polyol in the urethane-based adhesive composition within the above range, the surface protection film of the present invention can effectively exhibit the effects of the present invention.

[0052] In the urethane prepolymer, polyol, and polyfunctional isocyanate compound, the equivalent ratio of the NCO group to the OH group, expressed as NCO group / OH group, is preferably from 1.0 to 2.0, more preferably from 1.1 to 1.9, still more preferably from 1.2 to 1.8, and particularly preferably from 1.2 to 1.7. By adjusting the equivalent ratio of the NCO group / OH group within the above range, the surface protection film according to the embodiment of the present invention is excellent in wettability even when laminated on a substrate having a large surface step, and further, due to excellent step-following properties, a sufficiently high adhesion rate can be achieved.

[0053] The content ratio of the polyfunctional isocyanate compound in the urethane-based pressure-sensitive adhesive composition is preferably from 2.5 parts by weight to 40 parts by weight, more preferably from 4 parts by weight to 30 parts by weight, still more preferably from 5 parts by weight to 20 parts by weight, and particularly preferably from 6 parts by weight to 15 parts by weight with respect to 100 parts by weight in total of the urethane prepolymer and polyol. By adjusting the content ratio of the polyfunctional isocyanate compound within the above range, the surface protection film according to the embodiment of the present invention is excellent in wettability even when laminated on a substrate having a large surface step, and further, due to excellent step-following properties, a sufficiently high adhesion rate can be achieved.

[0054] <1-1-A-1. Urethane prepolymer> The urethane prepolymer is typically a polyurethane polyol, and is preferably obtained by reacting a polyether polyol and an organic polyisocyanate compound in the presence or absence of a catalyst with the organic polyisocyanate compound. As the urethane prepolymer, a commercially available urethane prepolymer may be employed.

[0055] The urethane prepolymer may be only one kind or two or more kinds.

[0056] The number average molecular weight Mn of the urethane prepolymer is preferably from 1000 to 100000.

[0057] As the polyether polyol, any appropriate polyether polyol can be used as long as the effects of the present invention are not impaired. Examples of such polyether polyols include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using low molecular weight polyols such as water, propylene glycol, ethylene glycol, glycerin, and trimethylolpropane as initiators. Examples of such polyether polyols include polyether polyols having a functional group number of 2 or more, such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol.

[0058] The molecular weight of the polyether polyol can be used from low molecular weight to high molecular weight. The molecular weight of the polyether polyol preferably has a number average molecular weight of 1000 to 5000. If the number average molecular weight is less than 1000, the reactivity increases and there is a risk of easy gelation. If the number average molecular weight exceeds 5000, the reactivity decreases, and furthermore, the cohesive force of the polyurethane polyol itself may decrease. The usage amount of the polyether polyol (p2) is preferably 10 mol% to 100 mol% in the polyols constituting the urethane prepolymer (typically, polyurethane polyol).

[0059] If necessary, a part of the polyether polyol can be replaced and used in combination with glycols such as ethylene glycol, 1,4 - butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, pentaerythritol, and polyvalent amines such as ethylenediamine, N - aminoethylethanolamine, isophoronediamine, and xylylenediamine.

[0060] As the polyether polyol, only a bifunctional polyether polyol may be used, or a polyether polyol having a number average molecular weight of 1000 to 5000 and at least 3 or more hydroxyl groups in one molecule may be partially or entirely used. When a polyether polyol having a number average molecular weight of 1000 to 5000 and at least 3 or more hydroxyl groups in one molecule is partially or entirely used as the polyether polyol, a good balance between adhesiveness and peelability can be achieved. In such a polyether polyol, if the number average molecular weight is less than 1000, the reactivity increases and there is a risk of easy gelation. Also, in such a polyether polyol, if the number average molecular weight exceeds 5000, the reactivity decreases, and furthermore, the cohesive force of the urethane prepolymer (typically, polyurethane polyol) itself may become small. The number average molecular weight of such a polyether polyol is more preferably 2500 to 3500.

[0061] Such polyether polyols can be used alone or in combination.

[0062] When the urethane prepolymer has the structural unit represented by the above general formula (1), the polyether polyol preferably contains a polyether polyol having the structural unit represented by the above general formula (1). The polyether polyol having the structural unit represented by the above general formula (1) preferably contains a structural unit having 3 or more carbon atoms (polyoxyalkylene unit) in which all of a plurality of Rs 1 are hydrogen atoms, and more preferably is polytetramethylene glycol.

[0063] The content ratio of the polyether polyol having the structural unit represented by the above general formula (1) with respect to the total amount of the polyether polyol is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and for example, 100% by weight or less, preferably 90% by weight or less.

[0064] When the urethane prepolymer has a structural unit represented by the general formula (2), the polyether polyol preferably includes, in addition to the polyether polyol having a structural unit represented by the general formula (1), a polyether polyol having a structural unit represented by the general formula (2). The polyether polyol having a structural unit represented by the general formula (2) preferably contains a structural unit (polyoxypropylene unit) in which one of a plurality of Rs 2 is a methyl group and the rest are hydrogen atoms, and more preferably is polypropylene glycol.

[0065] The content ratio of the polyether polyol having a structural unit represented by the general formula (2) with respect to the total amount of the polyether polyol is, for example, 0% by weight or more, preferably 10% by weight or more, and for example, 50% by weight or less, preferably 40% by weight or less, and more preferably 30% by weight or less.

[0066] When the urethane prepolymer does not have a structural unit represented by the general formula (1), the urethane prepolymer is preferably obtained by reacting a polyether polyol having no structural unit represented by the general formula (1), a polyester polyol, and an organic polyisocyanate compound. In this case, the polyether polyol is preferably a polyether polyol having a structural unit represented by the general formula (2), and more preferably is polypropylene glycol.

[0067] As the polyester polyol, any suitable polyester polyol can be used as long as the effects of the present invention are not impaired. Examples of such polyester polyols include polyester polyols obtained by reacting an acid component and a glycol component. Examples of the acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, and polyol components such as glycerin, trimethylolpropane, and pentaerythritol. In addition to these, examples of the polyester polyol include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0068] The molecular weight of the polyester polyol can be used from low molecular weight to high molecular weight. The number average molecular weight of the polyester polyol is preferably 500 to 5000. If the number average molecular weight is less than 500, the reactivity increases and there is a risk of gelation. If the number average molecular weight exceeds 5000, the reactivity decreases, and furthermore, the cohesive force of the polyurethane polyol itself may decrease. The usage amount of the polyester polyol is preferably 10 mol% to 90 mol% in the polyol constituting the urethane prepolymer (typically, polyurethane polyol).

[0069] As the organic polyisocyanate compound, any suitable organic polyisocyanate compound can be used as long as the effects of the present invention are not impaired. Examples of such organic polyisocyanate compounds include aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates.

[0070] Examples of aromatic polyisocyanates include aromatic diisocyanates such as 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, etc.; aromatic triisocyanates such as 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4''-triphenylmethane triisocyanate, etc.

[0071] Examples of aliphatic polyisocyanates include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, etc.

[0072] Examples of aromatic aliphatic polyisocyanates include aromatic aliphatic diisocyanates such as ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, etc.

[0073] Examples of the alicyclic polyisocyanate include alicyclic diisocyanates such as 3-isocyanatomethyl-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(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, etc.

[0074] As the organic polyisocyanate compound, a trimethylolpropane adduct, a biuret compound reacted with water, and an isocyanurate compound (for example, a trimer) having an isocyanurate ring can be used in combination.

[0075] Such organic polyisocyanate compounds can be used alone or in combination. As the organic polyisocyanate compound, a diisocyanate is more preferable, an aliphatic diisocyanate is further preferable, and hexamethylene diisocyanate is particularly preferable.

[0076] As the catalyst that can be used in producing a urethane prepolymer (typically, a polyurethane polyol), any appropriate catalyst can be used as long as the effects of the present invention are not impaired. Examples of such a catalyst include a tertiary amine-based compound and an organometallic-based compound.

[0077] Examples of the tertiary amine-based compound include triethylamine, triethylenediamine, 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU).

[0078] Examples of the organometallic-based compound include a tin-based compound and a non-tin-based compound.

[0079] Examples of tin-based 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.

[0080] Examples of non-tin-based compounds include titanium-based compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead-based compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron-based compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium-based compounds such as zirconium naphthenate.

[0081] When a catalyst is used in the production of a urethane prepolymer (typically a polyurethane polyol), the catalyst can be used alone or in combination. Among the catalysts, tin-based compounds are preferred, and dibutyltin dilaurate (DBTDL) is more preferred.

[0082] When a catalyst is used in the production of a urethane prepolymer (typically a polyurethane polyol), the amount of the catalyst used is preferably 0.01% to 1.0% by weight based on the total amount of the polyol and the organic polyisocyanate compound.

[0083] When a catalyst is used in the production of a urethane prepolymer (typically, a polyurethane polyol), the reaction temperature is preferably less than 100°C, more preferably 85°C to 95°C. When the temperature exceeds 100°C, the reaction rate and control of the crosslinked structure may become difficult, and it may be difficult to obtain a urethane prepolymer (typically, a polyurethane polyol) having a predetermined molecular weight.

[0084] When producing a urethane prepolymer (typically, a polyurethane polyol), a catalyst may not be used. In that case, the reaction temperature is preferably 100°C or higher, more preferably 110°C or higher. Also, when obtaining a urethane prepolymer (typically, a polyurethane polyol) without a catalyst, it is preferable to react for 3 hours or more.

[0085] Examples of methods for producing a urethane prepolymer (typically, a polyurethane polyol) include: 1) a method of charging all of a polyol such as a polyether polyol, a catalyst, and an organic polyisocyanate compound into a flask; and 2) a method of charging a polyol such as a polyether polyol and a catalyst into a flask and adding an organic polyisocyanate compound dropwise. In terms of controlling the reaction, method 2) is preferable as a method for producing a urethane prepolymer (typically, a polyurethane polyol).

[0086] When producing a urethane prepolymer (typically, a polyurethane polyol), any suitable solvent can be used as long as the effects of the present invention are not impaired. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Among these solvents, ethyl acetate and toluene are preferred.

[0087] <1-1-A-2.Polyol> Examples of polyols include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols.

[0088] As the polyester polyol, for example, it can be obtained by an esterification reaction between a polyol component and an acid component.

[0089] Examples of the polyol component 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.

[0090] 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 their acid anhydrides.

[0091] Examples of the polyether polyol 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 (such as propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (such as bisphenol A), and dihydroxybenzenes (such as catechol, resorcinol, hydroquinone, etc.) as initiators. Specifically, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. are included.

[0092] Examples of the polycaprolactone polyol include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

[0093] Examples of the polycarbonate polyol include: polycarbonate polyols obtained by polycondensation reaction of the above polyol component and phosgene; polycarbonate polyols obtained by transesterification condensation of the above polyol component and diesters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and dibenzyl carbonate; copolymer polycarbonate polyols obtained by using two or more of the above polyol components in combination; polycarbonate polyols obtained by esterification reaction of the above various polycarbonate polyols and carboxyl group-containing compounds; polycarbonate polyols obtained by etherification reaction of the above various polycarbonate polyols and hydroxyl group-containing compounds; polycarbonate polyols obtained by transesterification reaction of the above various polycarbonate polyols and ester compounds; polycarbonate polyols obtained by transesterification reaction of the above various polycarbonate polyols and hydroxyl group-containing compounds; polyester-based polycarbonate polyols obtained by polycondensation reaction of the above various polycarbonate polyols and dicarboxylic acid compounds; copolymer polyether-based polycarbonate polyols obtained by copolymerizing the above various polycarbonate polyols and alkylene oxide.

[0094] Examples of the castor oil-based polyol include castor oil-based polyols obtained by reacting castor oil fatty acid with the above polyol component. Specifically, for example, castor oil-based polyols obtained by reacting castor oil fatty acid with polypropylene glycol can be mentioned.

[0095] As the polyol, preferably a polyether polyol is mentioned, more preferably a polyether polyol having a structural unit represented by the above general formula (1) is mentioned. The polyether polyol having a structural unit represented by the above general formula (1) preferably contains a structural unit having 3 or more carbon atoms in which one of a plurality of Rs 1 is a hydroxyalkyl group and the rest are hydrogen atoms, and more preferably contains a structural unit having 4 carbon atoms in which one of a plurality of Rs 1 is a hydroxyalkyl group and the rest are hydrogen atoms.

[0096] The polyol typically includes a first polyol having a number average molecular weight Mn of 5000 to 20000 and a second polyol having a number average molecular weight Mn of 300 to 4999. By the polyol including a first polyol having a number average molecular weight Mn of 5000 to 20000 and a second polyol having a number average molecular weight Mn of 300 to 4999, the effects of the present invention can be more exhibited.

[0097] The first polyol may be only one kind or two or more kinds.

[0098] The second polyol may be only one kind or two or more kinds.

[0099] The content ratio of the total amount 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, still 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 terms of more exhibiting the effects of the present invention.

[0100] The number average molecular weight Mn of the first polyol is from 5,000 to 20,000, preferably from 6,000 to 18,000, more preferably from 7,000 to 16,000, still more preferably from 8,000 to 15,000, and particularly preferably from 9,000 to 14,000. If 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 expressed.

[0101] The number average molecular weight Mn of the second polyol is from 300 to 4,999, preferably from 350 to 4,500, more preferably from 400 to 4,000, still more preferably from 500 to 3,800, and particularly preferably from 700 to 3,500. If 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 expressed.

[0102] The weight ratio of the first polyol to the second polyol is preferably 1.0 ≤ (the first polyol / the second polyol) ≤ 3.5, more preferably 1.0 ≤ (the first polyol / the second polyol) ≤ 3.0, still more preferably 1.0 ≤ (the first polyol / the second polyol) ≤ 2.5, and particularly preferably 1.0 ≤ (the first polyol / the second polyol) ≤ 2.0. If the weight ratio of the first polyol to the second polyol is within the above range, further reduction of the haze of the surface protection film can be achieved.

[0103] In terms of more effectively expressing the effects of the present invention, the number of OH groups of the first polyol is preferably from 3 to 6, more preferably from 3 to 5, still more preferably from 3 to 4, and particularly preferably 3.

[0104] In terms of more effectively expressing the effects of the present invention, the first polyol preferably contains from 50% by weight to 100% by weight, more preferably from 70% by weight to 100% by weight, still more preferably from 90% by weight to 100% by weight, particularly preferably from 95% by weight to 100% by weight, and most preferably substantially 100% by weight of a triol having 3 OH groups.

[0105] The first polyol is, particularly preferably, a polyether polyol containing a structural unit represented by the above general formula (2).

[0106] In terms of more effectively expressing the effects of the present invention, the number of OH groups in the second polyol is preferably 3 to 6, more preferably 3 to 5, still more preferably 3 to 4, and particularly preferably 3.

[0107] In terms of more effectively expressing the effects of the present invention, the second polyol preferably contains 50% to 100% by weight, more preferably 70% to 100% by weight, still more preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably substantially 100% by weight of a triol having 3 OH groups.

[0108] The second polyol is, particularly preferably, a polyether polyol containing a structural unit represented by the above general formula (1) or a polyether polyol containing a structural unit represented by the above general formula (2), and particularly preferably, a polyether polyol containing a structural unit represented by the above general formula (1).

[0109] <1-1-A-3. Polyfunctional Isocyanate Compound> The polyfunctional isocyanate compound may be only one kind or two or more kinds.

[0110] As the polyfunctional isocyanate compound, any suitable polyfunctional isocyanate compound that can be used in the urethanization reaction can be adopted. Examples of such polyfunctional isocyanate compounds include polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanates, polyfunctional aromatic isocyanate compounds, and polyfunctional araliphatic diisocyanate compounds.

[0111] Examples of the polyfunctional aliphatic isocyanate compound include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

[0112] Examples of the polyfunctional alicyclic isocyanate compound include alicyclic diisocyanates such as 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated tetramethylxylylene diisocyanate, and the like.

[0113] Examples of the polyfunctional aromatic diisocyanate compound include aromatic diisocyanates such as phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and the like.

[0114] Examples of the polyfunctional araliphatic diisocyanate compound include aromatic diisocyanates such as xylylene diisocyanate and the like.

[0115] Examples of the polyfunctional isocyanate compound also include trimethylolpropane adducts of various polyfunctional isocyanate compounds as described above, biuret compounds reacted with water, and isocyanurate compounds having an isocyanurate ring (e.g., trimer). These may also be used in combination.

[0116] The polyfunctional isocyanate compound preferably has an average functionality of the isocyanate groups of 2 to 6, more preferably 2 to 5, and even more preferably 3 to 4, in that the effects of the present invention can be more expressed.

[0117] More preferably, the polyfunctional isocyanate compound is an isocyanate compound having an average functionality of 3 or more, still more preferably an isocyanurate of an aliphatic diisocyanate, and particularly preferably an isocyanurate of hexamethylene diisocyanate.

[0118] <1-1-B. Embodiment in which the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyfunctional isocyanate compound> In the embodiment of (B), the urethane-based pressure-sensitive adhesive is a urethane-based pressure-sensitive adhesive produced by the prepolymer method, and is formed from a urethane-based pressure-sensitive adhesive composition containing a urethane prepolymer and a polyfunctional isocyanate compound. In the embodiment of (B), the urethane prepolymer contained in the urethane-based pressure-sensitive adhesive composition is the same as the urethane prepolymer described in <1-1-A-1> above, and the polyfunctional isocyanate compound contained in the urethane-based pressure-sensitive adhesive composition is the same as the polyfunctional isocyanate compound described in <1-1-A-3> above. In the embodiment of (B), the urethane-based pressure-sensitive adhesive composition does not contain the polyol described in <1-1-A-2> above. More specifically, in the embodiment of (B), the urethane-based pressure-sensitive adhesive is formed by curing a urethane-based pressure-sensitive adhesive composition containing a urethane prepolymer and a polyfunctional isocyanate compound. The urethane prepolymer preferably reacts with the polyfunctional isocyanate compound to form a urethane-based resin.

[0119] In the embodiment of (B), the urethane prepolymer has a structural unit represented by the above general formula (1). Therefore, a urethane resin formed by the urethane reaction of the urethane prepolymer and the polyfunctional isocyanate compound contains a structural unit derived from the structural unit represented by the above general formula (1) (hereinafter referred to as a structural unit derived from general formula (1)). The structural unit derived from general formula (1) in the urethane resin and its content ratio are as described in the above <1-1-A.>

[0120] Further, in the embodiment of (B), since the urethane prepolymer preferably has a structural unit represented by the above general formula (2), the urethane resin contains the structural unit represented by the above general formula (2). The content ratio of the structural unit represented by general formula (2) in the urethane resin is as described in the above <1-1-A.>

[0121] The range of the weight ratio of the total amount of the urethane prepolymer and the polyfunctional isocyanate compound in the urethane adhesive composition is the same as the range of the weight ratio of the total amount of the urethane prepolymer, the polyol, and the polyfunctional isocyanate compound in the embodiment of (A). The range of the equivalent ratio of the NCO group to the OH group in the urethane prepolymer and the polyfunctional isocyanate compound in the urethane adhesive composition is the same as the range of the equivalent ratio of the NCO group to the OH group in the urethane prepolymer, the polyol, and the polyfunctional isocyanate compound in the embodiment of (A). The range of the content ratio of the polyfunctional isocyanate compound with respect to 100 parts by weight of the urethane prepolymer is the same as the range of the content ratio of the polyfunctional isocyanate compound with respect to 100 parts by weight in total of the urethane prepolymer and the polyol in the embodiment of (A).

[0122] <1-1-C. Embodiment in which the urethane adhesive composition contains a polyol and a polyfunctional isocyanate compound> In the embodiment of (C), the urethane adhesive is a urethane adhesive produced by a one-shot method and is formed from a urethane adhesive composition containing a polyol and a polyfunctional isocyanate compound. In the aspect of (C), the polyol contained in the urethane-based pressure-sensitive adhesive composition is the same as the polyol described in <1-1-A-2> above, and the polyfunctional isocyanate compound contained in the urethane-based pressure-sensitive adhesive composition is the same as the polyfunctional isocyanate compound described in <1-1-A-3> above. In the aspect of (C), the urethane-based pressure-sensitive adhesive composition does not contain the urethane prepolymer described in <1-1-A-1> above. More specifically, in the aspect of (C), the urethane-based pressure-sensitive adhesive is formed by curing a urethane-based pressure-sensitive adhesive composition containing a polyol and a polyfunctional isocyanate compound. The polyol preferably reacts with the polyfunctional isocyanate compound to form a urethane-based resin.

[0123] In the aspect of (C), the polyol has a structural unit represented by the above general formula (1). Therefore, the urethane-based resin formed by the urethane reaction between the polyol and the polyfunctional isocyanate compound contains a structural unit derived from the structural unit represented by the above general formula (1) (hereinafter referred to as the general formula (1)-derived structural unit). The general formula (1)-derived structural unit in the urethane resin and its content ratio are as described in <1-1-A.> above.

[0124] Also, in the aspect of (C), the polyol preferably contains, in addition to the polyol having a structural unit derived from the structural unit represented by the general formula (1), a polyol having a structural unit represented by the above general formula (2). Therefore, the urethane-based resin contains the structural unit represented by the above general formula (2). The content ratio of the structural unit represented by the general formula (2) in the urethane resin is as described in <1-1-A.> above.

[0125] The range of the weight ratio of the total amount of the polyol and the polyfunctional isocyanate compound in the urethane-based pressure-sensitive adhesive composition is the same as the range of the weight ratio of the total amount of the urethane prepolymer, the polyol, and the polyfunctional isocyanate compound in the aspect of (A) above. The range of the equivalent ratio of the NCO group to the OH group in the polyol and the polyfunctional isocyanate compound in the urethane-based adhesive composition is the same as the range of the equivalent ratio of the NCO group to the OH group in the urethane prepolymer and the polyol and the polyfunctional isocyanate compound in the aspect (A) above. The range of the content ratio of the polyfunctional isocyanate compound with respect to 100 parts by weight of the polyol is the same as the range of the content ratio of the polyfunctional isocyanate compound with respect to the total 100 parts by weight of the urethane prepolymer and the polyol in the aspect (A) above.

[0126] <1-2. Other components> The urethane-based adhesive composition may contain any suitable other components as long as the effects of the present invention are not impaired. Examples of such other components include resin components other than the above urethane prepolymer and polyol, crosslinking agents other than the above polyfunctional isocyanate compound, crosslinking retardants, ionic compounds, fluorine-based additives, silicone-based additives, fatty acid esters, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, and catalysts.

[0127] 〔Ionic compound〕 When an ionic compound is included as another component, the antistatic performance of the surface protection film according to the embodiment of the present invention can be improved.

[0128] As the content ratio of the ionic compound, any appropriate content ratio can be adopted as long as the effects of the present invention are not impaired. In terms of being able to further improve the antistatic performance of the surface protection film of the present invention, the content ratio of the ionic compound with respect to the total 100 parts by weight of the urethane prepolymer and the polyol is preferably 0.05 part by weight or more, more preferably 0.10 part by weight to 50 parts by weight, still more preferably 0.20 part by weight to 30 parts by weight, particularly preferably 0.30 part by weight to 10 parts by weight, and most preferably 0.30 part by weight to 0.5 part by weight. More specifically, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (A), since the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyol, the content ratio of the ionic compound is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (B), since the urethane-based pressure-sensitive adhesive composition does not contain a polyol (i.e., it is 0 parts by weight), the range of the content ratio of the ionic compound with respect to 100 parts by weight of the urethane prepolymer is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (C), since the urethane-based pressure-sensitive adhesive composition does not contain a urethane prepolymer (i.e., it is 0 parts by weight), the range of the content ratio of the ionic compound with respect to 100 parts by weight of the polyol is as described above. If the content ratio of the ionic compound is within the above range, the antistatic performance of the surface protection film of the present invention can be further improved. If the content ratio of the ionic compound is too low outside the above range, there is a possibility that sufficient antistatic performance cannot be imparted to the surface protection film of the present invention. If the content ratio of the ionic compound is too high outside the above range, there is a possibility that the contamination of the adherend increases.

[0129] As the ionic compound, any appropriate ionic compound can be adopted as long as the effects of the present invention are not impaired. The ionic compound may be only one kind or two or more kinds.

[0130] As the ionic compound, in terms of being able to more effectively exhibit the effects of the present invention, preferably, an ionic compound containing at least one selected from onium cations and metal cations and a fluoro organic anion, or an ionic group-containing silicone oligomer. More preferably, it is an ionic compound containing at least one selected from onium cations and metal cations and a fluoro organic anion in terms of making the appearance of the pressure-sensitive adhesive layer more excellent.

[0131] The ionic compound may be an ionic liquid. The ionic liquid means a molten salt (ionic compound) that is liquid at 25°C.

[0132] As the silicone oligomer containing an ionic group, any appropriate silicone oligomer containing an ionic group can be adopted as long as the effects of the present invention are not impaired. Examples of the silicone oligomer containing an ionic group include the product named "X-40-2450" manufactured by Shin-Etsu Chemical Co., Ltd.

[0133] As the onium cation, any appropriate onium cation can be adopted as long as the effects of the present invention are not impaired. In terms of being able to more effectively exhibit 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 an ammonium cation.

[0134] As the metal cation, any appropriate metal cation can be adopted as long as the effects of the present invention are not impaired. In terms of being able to more effectively exhibit the effects of the present invention, such a metal cation is preferably an alkali metal cation such as a Li cation, a Na cation, or a K cation.

[0135] As the fluoro organic anion, any appropriate fluoro organic anion can be adopted as long as the effects of the present invention are not impaired. The fluoro organic anion may be completely fluorinated (perfluorinated) or partially fluorinated.

[0136] Examples of such fluoro organic anions include fluorinated aryl sulfonates, perfluoroalkane sulfonates, bis(fluorosulfonyl)imide, bis(perfluoroalkane sulfonyl)imide, cyano perfluoroalkane sulfonyl amide, bis(cyano)perfluoroalkane sulfonyl methide, cyano-bis-(perfluoroalkane sulfonyl)methide, tris(perfluoroalkane sulfonyl)methide, trifluoroacetate, perfluoroalkylate, tris(perfluoroalkane sulfonyl)methide, (perfluoroalkane sulfonyl)trifluoroacetamide, and the like.

[0137] Among these fluoro organic anions, perfluoroalkyl sulfonate, bis(fluorosulfonyl)imide, and bis(perfluoroalkane sulfonyl)imide are preferred in terms of more effectively expressing the effects of the present invention. More specifically, for example, trifluoromethane sulfonate, pentafluoroethane sulfonate, heptafluoropropane sulfonate, nonafluorobutane sulfonate, bis(fluorosulfonyl)imide, and bis(trifluoromethane sulfonyl)imide are preferred, and bis(fluorosulfonyl)imide and bis(trifluoromethane sulfonyl)imide are more preferred.

[0138] As the ionic compound, an ionic compound composed of an onium cation and a fluoro organic anion is more preferred in terms of more effectively expressing the effects of the present invention.

[0139] The onium cation preferably has at least one selected from the structures represented by general formulas (3) to (6).

Chemical formula

[0140] 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 as or different from each other and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom. However, when the nitrogen atom contains a double bond, Rc is absent.

[0141] 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 are the same as or different from each other and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom.

[0142] 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 are the same as or different from each other and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may contain a heteroatom.

[0143] 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 as or different from each other and represent a hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom. However, when Z is a sulfur atom, Ro is absent.

[0144] 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, a cation structure having a pyrrole skeleton, and the like.

[0145] Specific examples of the cation represented by the general formula (3) include, for example, 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, 1,1-dimethylpyrrolidinium cation; pyrrolidinium cations such as 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 cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation; piperidinium cations such as 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, 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, 1-propyl-1-butylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1,1-dibutylpiperidinium cation; 2-methyl-1-pyrroline cation;1-Ethyl-2-phenylindole cation; 1,2-dimethylindole cation; 1-ethylcarbazole cation; cations having at least one selected from a vinyl group (CH2=CH-group) and an allyl group (CH2=CH-CH2-group); and the like.

[0146] Among these, in terms of further expressing the effects of the present invention, preferably, 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; pyrrolidinium cations such as 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 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, 1-propyl-1-butylpiperidinium cation; cations in which these cations further have at least one selected from a vinyl group (CH2=CH- group) and an allyl group (CH2=CH-CH2- group);Examples include, and more preferably include, 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 in which these cations further have at least one selected from a vinyl group (CH2=CH-group) and an allyl group (CH2=CH-CH2-group).;

[0147] Examples of the cation structure represented by the general formula (4) include, for example, an imidazolium cation structure, a tetrahydropyrimidinium cation structure, a dihydropyrimidinium cation structure, and the like.

[0148] Specific examples of the cation represented by the 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, 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethylimidazolium cation and other imidazolium cations; 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation and other tetrahydropyrimidinium cations; 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 other dihydropyrimidinium cations; cations having at least one selected from a vinyl group (CH2=CH- group) and an allyl group (CH2=CH-CH2- group) among these cations; and the like.

[0149] Among these, in terms of being more capable of expressing the effects of the present invention, preferably, 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, imidazolium cations such as cations having at least one selected from a vinyl group (CH2=CH-group) and an allyl group (CH2=CH-CH2-group) among these cations, more preferably, 1-ethyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, cations having at least one selected from a vinyl group (CH2=CH-group) and an allyl group (CH2=CH-CH2-group) among these cations.

[0150] Examples of the cation structure represented by the general formula (5) include a pyrazolium cation structure and a pyrazolinium cation structure.

[0151] Specific examples of the cation represented by the general formula (5) include, for example, pyrazolium cations such as 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation, 1-ethyl-2,3,5-trimethylpyrazolium cation, 1-propyl-2,3,5-trimethylpyrazolium cation, 1-butyl-2,3,5-trimethylpyrazolium cation; pyrazolinium cations such as 1-ethyl-2,3,5-trimethylpyrazolinium cation, 1-propyl-2,3,5-trimethylpyrazolinium cation, 1-butyl-2,3,5-trimethylpyrazolinium cation; cations having at least one selected from a vinyl group (CH2=CH-group) and an allyl group (CH2=CH-CH2-group) among these cations; and the like.

[0152] Examples of the cation structure represented by the general formula (6) include a tetraalkylammonium cation structure, a trialkylsulfonium cation structure, a tetraalkylphosphonium cation structure, and those in which a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group.

[0153] Specific examples of the cation represented by the general formula (6) include, for example, 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, 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, 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, etc.; Trialkylsulfonium cations such as trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, etc.; Tetraalkylphosphonium cations such as tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, etc.; Cations having at least one selected from a vinyl group (CH2=CH-group) and an allyl group (CH2=CH-CH2-group) among these cations; and the like.

[0154] As the ionic compound, preferably, an ionic compound containing at least one selected from the above-mentioned onium cations and the above-mentioned metal cations and the above-mentioned fluoro organic anion, or an ionic group-containing silicone oligomer, more preferably, an ionic compound containing at least one selected from the above-mentioned onium cations and the above-mentioned metal cations and the above-mentioned fluoro organic anion, and still more preferably, an ionic compound containing the above-mentioned onium cation and the above-mentioned fluoro organic anion.

[0155] In terms of being able to more effectively exhibit the effects of the present invention, as the ionic compound, 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 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 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-methyl-imidazolium trifluoromethanesulfonate, 1-allyl-3-methyl-imidazolium 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, and 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, and particularly 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.

[0156] As the ionic compound, commercially available ones may be used, or those synthesized by any suitable method may be used. 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, etc., as described in "Ionic Liquids - The Cutting Edge of Development and the Future -" (published by CMC Publishing).

[0157] [Fluorine-based additive] When a fluorine-based additive is included as another component, the light peelability and antistatic performance of the surface protection film according to the embodiment of the present invention can be further improved.

[0158] As the fluorine-based additive, any suitable fluorine-based additive can be employed as long as the effects of the present invention are not impaired.

[0159] The fluorine-based additive may be only one kind, or two or more kinds.

[0160] The content ratio of the fluorine-based additive with respect to a total of 100 parts by weight of the above urethane prepolymer and polyol is preferably 0.01 part by weight or more, more preferably 0.03 part by weight to 30 parts by weight, still more preferably 0.05 part by weight to 10 parts by weight, and particularly preferably 0.05 part by weight to 1 part by weight. More specifically, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (A), since the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyol, the content ratio of the fluorine-based additive is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (B), since the urethane-based pressure-sensitive adhesive composition does not contain a polyol (that is, it is 0 part by weight), the range of the content ratio of the fluorine-based additive with respect to 100 parts by weight of the urethane prepolymer is as described above. Moreover, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (C), since the urethane-based pressure-sensitive adhesive composition does not contain a urethane prepolymer (that is, it is 0 part by weight), the content ratio of the fluorine-based additive with respect to 100 parts by weight of the polyol is as described above. If the content ratio of the fluorine-based additive is within the above range, it becomes possible to further improve the easy peelability and antistatic performance of the surface protection film according to the embodiment of the present invention.

[0161] Examples of the fluorine-based additive include at least one selected from fluorine-containing compounds, hydroxyl group-containing fluorine-based compounds, and crosslinkable functional group-containing fluorine-based compounds.

[0162] Examples of the fluorine-containing compound include compounds having a fluoroaliphatic hydrocarbon skeleton, fluorine-containing organic compounds obtained by copolymerizing an organic compound and a fluorine-based compound, and fluorine-containing compounds containing an organic compound. Examples of the fluoroaliphatic hydrocarbon skeleton include fluoro C1 to C10 alkanes such as fluoromethane, fluoroethane, fluoropropane, fluoroisopropane, fluorobutane, fluoroisobutane, fluorot-butane, fluoropentane, and fluorohexane. Here, the notation "C1 to C10" means that the number of carbon atoms is 1 to 10.

[0163] Preferred embodiments of the fluorine-containing compound are oligomers having a fluorine-containing group and a hydrophilic group and / or a lipophilic group (hereinafter referred to as "specific fluorine-based compounds"). By adopting such "specific fluorine-based compounds", it becomes possible to improve the light peelability and antistatic performance of the surface protection film according to the embodiments of the present invention. In particular, by using such "specific fluorine-based compounds" in combination with ionic compounds, it becomes possible to further improve the light peelability and antistatic performance of the surface protection film according to the embodiments of the present invention. This is presumably because the ionic compounds are unevenly distributed on the surface side (the side adhered to the adherend) of the urethane-based pressure-sensitive adhesive layer by the specific fluorine-based compounds. Representative examples of the fluorine-containing group include a fluorine-containing alkyl group (e.g., CF3-) and / or a fluorine-containing alkylene group (e.g., -CF2-CF2-). The hydrophilic group is a group having hydrophilicity, and hydrophilicity is a property generally known to those skilled in the art as meaning "having an affinity for water" in English (see, for example, McGraw-Hill Dictionary of Scientific and Technical Terms (Revised 3rd Edition, Nikkan Kogyo Shimbun, Ltd.)). The lipophilic group is a group having lipophilicity, and lipophilicity is a property generally known to those skilled in the art as meaning "having an affinity for oil" in English (see, for example, McGraw-Hill Dictionary of Scientific and Technical Terms (Revised 3rd Edition, Nikkan Kogyo Shimbun, Ltd.)).

[0164] From the viewpoint of further improving the antistatic performance and light peelability of the surface protection film according to the embodiments of the present invention, the surface tension of the fluorine-containing compound as a 0.1% toluene solution is preferably 19.0 mJ / m 2 ~28.0 mJ / m 2 and more preferably 19.0 mJ / m 2 ~26.0 mJ / m 2 (the surface tension of toluene is 27.9 mN / m). Thus, if the surface tension of the fluorine-containing compound as a 0.1% toluene solution is within the above range, the antistatic performance and light peelability of the surface protection film according to the embodiments of the present invention can be further improved.

[0165] Examples of commercially available fluorine-containing compounds include the following.

[0166] Megafac series manufactured by DIC Corporation: Typically, "Megafac F-114", "Megafac F-251", "Megafac F-253", "Megafac F-281", "Megafac F-410", "Megafac F-430", "Megafac F-444", "Megafac F-477", "Megafac F-510", "Megafac F-551-A", "Megafac F-553", "Megafac F-554", "Megafac F-555-A", "Megafac F-556", "Megafac F-557", "Megafac F-558", "Megafac F-559", "Megafac F-560", "Megafac F-561", "Megafac F-562", "Megafac F-563", "Megafac F-565", "Megafac F-568", "Megafac F-569", "Megafac F-570", "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", "Megafac RS-78", "Megafac RS-90", etc.

[0167] Surflon series manufactured by AGC Seimi Chemical Co., Ltd.: Typically, "S-242", "S-243", "S-386", etc.

[0168] FC series manufactured by Sumitomo 3M Limited: Typically, "FC-4430", "FC-4432", etc.

[0169] Fujent series manufactured by Neos Co., Ltd.: Typical examples include "Fujent 100", "Fujent 100C", "Fujent 110", "Fujent 150", "Fujent 150CH", "Fujent 250", "Fujent 400SW", etc.

[0170] PF series manufactured by Kitamura Chemical Industry Co., Ltd.: Typical examples include "PF-136A", "PF-156A", "PF-151N", "PF-636", "PF-6320", "PF-656", "PF-6520", "PF-651", "PF-652", "PF-3320", etc.

[0171] As the hydroxyl group-containing fluorine-based compound, for example, conventionally known resins can be used. For example, hydroxyl group-containing fluorine resins described in WO94 / 06870 pamphlet, JP-A-8-12921, JP-A-10-72569, JP-A-4-275379, WO97 / 11130 pamphlet, WO96 / 26254 pamphlet, etc. can be mentioned. Other hydroxyl group-containing fluorine resins include, for example, fluoroolefin copolymers described in JP-A-8-231919, JP-A-10-265731, JP-A-10-204374, JP-A-8-12922, etc. In addition, copolymers of compounds having a fluorinated alkyl group in a hydroxyl group-containing compound, fluorine-containing organic compounds obtained by copolymerizing a fluorine-containing compound with a hydroxyl group-containing compound, fluorine-containing compounds containing a hydroxyl group-containing organic compound, etc. can be mentioned. As such hydroxyl group-containing fluorine-based compounds, commercially available products include, for example, the trade name "Lumiflon" (manufactured by Asahi Glass Co., Ltd.), the trade name "Cefral Coat" (manufactured by Central Glass Co., Ltd.), the trade name "Zafron" (manufactured by Toagosei Co., Ltd.), the trade name "Zefflu" (manufactured by Daikin Industries, Ltd.), etc.

[0172] Examples of the crosslinkable functional group-containing fluorine-based compounds include carboxylic acid compounds having a fluorinated alkyl group such as perfluorooctanoic acid, copolymers of a compound 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. Examples of such crosslinkable functional group-containing fluorine-based compounds include commercially available products such as "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", "Megafac RS-90" (manufactured by DIC Corporation).

[0173] Among the fluorine-containing compounds available as commercial products, those corresponding to the aforementioned "oligomer having a fluorine-containing group, a hydrophilic group, and / or a lipophilic group" typically include those manufactured by DIC Corporation, "Megafac F-477" (oligomer containing a fluorine-containing group, a hydrophilic group, and a lipophilic group, surface tension = 26.4 mN / m when in a 0.1% toluene solution), "Megafac F-551-A" (oligomer containing a fluorine-containing group and a lipophilic group, surface tension = 25.6 mN / m when in a 0.1% toluene solution), "Megafac F-553" (oligomer containing a fluorine-containing group, a hydrophilic group, and a lipophilic group, surface tension = 26.4 mN / m when in a 0.1% toluene solution), "Megafac F-554" (oligomer containing a fluorine-containing group and a lipophilic group, surface tension = 25.0 mN / m when in a 0.1% toluene solution), "Megafac F-555-A" (oligomer containing a fluorine-containing group, a hydrophilic group, and a lipophilic group, surface tension = 20.4 mN / m when in a 0.1% toluene solution), "Megafac F-557" (oligomer containing a fluorine-containing group, a hydrophilic group, and a lipophilic group, surface tension = 26.3 mN / m when in a 0.1% toluene solution), "Megafac F-559" (an oligomer containing a fluorine-containing group, a hydrophilic group, and a lipophilic group, surface tension = 26.1 mN / m when prepared as a 0.1% toluene solution), "Megafac F-563" (an oligomer containing a fluorine-containing group and a lipophilic group, surface tension = 20.2 mN / m when prepared as a 0.1% toluene solution), "Megafac F-569" (an oligomer containing a fluorine-containing group and a hydrophilic group, surface tension = 19.7 mN / m when prepared as a 0.1% toluene solution), etc. can be mentioned.

[0174] 〔Silicone-based additive〕 As another component, when a silicone-based additive is included, it becomes possible to further improve the easy peelability of the surface protection film according to the embodiment of the present invention.

[0175] As the silicone-based additive, any appropriate silicone-based additive can be adopted as long as the effects of the present invention are not impaired.

[0176] The silicone-based additive may be only one kind or two or more kinds.

[0177] The content ratio of the silicone-based additive with respect to a total of 100 parts by weight of the above urethane prepolymer and polyol is preferably 0.01 part by weight or more, more preferably 0.015 part by weight to 30 parts by weight, still more preferably 0.020 part by weight to 10 parts by weight, and particularly preferably 0.025 part by weight to 1 part by weight. More specifically, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (A), since the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyol, the content ratio of the silicone-based additive is as described above. Also, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (B), since the urethane-based pressure-sensitive adhesive composition does not contain a polyol (i.e., it is 0 part by weight), the range of the content ratio of the silicone-based additive with respect to 100 parts by weight of the urethane prepolymer is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above-mentioned aspect (C), since the urethane-based pressure-sensitive adhesive composition does not contain a urethane prepolymer (i.e., it is 0 parts by weight), the content ratio of the silicone-based additive to 100 parts by weight of the polyol is as described above. When the content ratio of the silicone-based additive is within the above range, it becomes possible to further improve the easy peelability of the surface protection film according to the embodiment of the present invention.

[0178] In terms of being able to more effectively exhibit the effects of the present invention, the content ratio of the total amount of the aforementioned fluorine-based additive and silicone-based additive to a total of 100 parts by weight of the urethane prepolymer and polyol is 0.01 parts by weight or more, more preferably 0.03 parts by weight to 30 parts by weight, still more preferably 0.05 parts by weight to 10 parts by weight, and particularly preferably 0.05 parts by weight to 1 part by weight. More specifically, when the urethane-based pressure-sensitive adhesive composition is in the above-mentioned aspect (A), since the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyol, the content ratio of the total amount of the fluorine-based additive and the silicone-based additive is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above-mentioned aspect (B), since the urethane-based pressure-sensitive adhesive composition does not contain a polyol (i.e., it is 0 parts by weight), the range of the content ratio of the total amount of the fluorine-based additive and the silicone-based additive to 100 parts by weight of the urethane prepolymer is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above-mentioned aspect (C), since the urethane-based pressure-sensitive adhesive composition does not contain a urethane prepolymer (i.e., it is 0 parts by weight), the content ratio of the fluorine-based additive and the silicone-based additive to 100 parts by weight of the polyol is as described above.

[0179] As the silicone-based additive, any suitable silicone-based additive can be employed 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.

[0180] Examples of the reactive silicone oil include side-chain type reactive silicone oils in which an organic group is bonded as a side chain to an Si atom used for a siloxane bond, both-end type reactive silicone oils in which an organic group is bonded to Si atoms located at both ends of the structure, one-end type 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 both-end type reactive silicone oils in which an organic group is bonded as a side chain to an Si atom used for a siloxane bond and an organic group is bonded to Si atoms located at both ends of the structure.

[0181] Examples of the side-chain type reactive silicone oils include amino-modified type side-chain reactive silicone oils, epoxy-modified type side-chain reactive silicone oils, carbinol-modified type side-chain reactive silicone oils, mercapto-modified type side-chain reactive silicone oils, carboxyl-modified type side-chain reactive silicone oils, and methylhydrogen silicone oil type side-chain reactive silicone oils. Examples of these commercially available products include various silicone oils commercially available as side-chain type reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0182] Examples of the both-terminal reactive silicone oils include amino-modified type both-terminal reactive silicone oils, epoxy-modified type both-terminal reactive silicone oils, carbinol-modified type both-terminal reactive silicone oils, methacryl-modified type both-terminal reactive silicone oils, polyether-modified type both-terminal reactive silicone oils, mercapto-modified type both-terminal reactive silicone oils, carboxyl-modified type both-terminal reactive silicone oils, phenol-modified type both-terminal reactive silicone oils, silanol-terminated type both-terminal reactive silicone oils, acrylic-modified type both-terminal reactive silicone oils, carboxylic anhydride-modified type both-terminal reactive silicone oils. Examples of these commercially available products include various silicone oils commercially available as both-terminal reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. In particular, carbinol-modified type both-terminal reactive silicone oils such as "KF-6000", "KF-6001", "KF-6002", "KF-6003", "KF-6028", etc. manufactured by Shin-Etsu Chemical Co., Ltd. can be preferably adopted.

[0183] Examples of the single-terminal reactive silicone oils include single-terminal reactive modified type single-terminal reactive silicone oils, and average single-terminal carboxyl-modified type single-terminal reactive silicone oils. Examples of these commercially available products include various silicone oils commercially available as single-terminal reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. In particular, carbinol-modified type single-terminal reactive silicone oils such as "X-22-170BX", "X-22-170DX", "X-22-4015", etc. manufactured by Shin-Etsu Chemical Co., Ltd. can be preferably adopted.

[0184] Examples of the side-chain both-terminal reactive silicone oils include side-chain amino·both-terminal methoxy-modified type side-chain both-terminal reactive silicone oils, and epoxy-modified type side-chain both-terminal reactive silicone oils. Examples of these commercially available products include various silicone oils commercially available as side-chain both-terminal reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0185] Examples of non-reactive silicone oils include side-chain type non-reactive silicone oils in which an organic group is bonded as a side chain to an Si atom that is subjected to a siloxane bond, and both-end type non-reactive silicone oils in which an organic group is bonded to Si atoms located at both ends of the structure.

[0186] Examples of side-chain type non-reactive silicone oils include polyether-modified type side-chain non-reactive silicone oils, aralkyl-modified type side-chain non-reactive silicone oils, Flolo alkyl-modified type side-chain non-reactive silicone oils, long-chain alkyl-modified type side-chain non-reactive silicone oils, higher fatty acid ester-modified type side-chain non-reactive silicone oils, higher fatty acid-containing type side-chain non-reactive silicone oils, and phenyl-modified type side-chain non-reactive silicone oils. Examples of these commercially available products include various silicone oils commercially available as side-chain type non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. In particular, polyether-modified type side-chain non-reactive silicone oils such as "KF-351A", "KF-352A", "KF-353", "KF-354L", "KF-355A", "KF-615A", "KF-945", "KF-640", "KF-642", "KF-643", "KF-644", "KF-6020", "KF-6204", "X-22-4515", etc. manufactured by Shin-Etsu Chemical Co., Ltd. can be preferably employed.

[0187] Among these polyether-modified types of side-chain non-reactive silicone oils, polyether-modified types of side-chain non-reactive silicone oils with an HLB value of preferably 3 or more, more preferably 8 or more, still more preferably 9 or more, and particularly preferably 10 or more are preferred in that they can further reduce the amount of residue. Examples of such polyether-modified types of side-chain non-reactive silicone oils include "KF-351A" (HLB = 12), "KF-353" (HLB = 10), "KF-354L" (HLB = 16), "KF-355A" (HLB = 12), "KF-615A" (HLB = 10), "KF-640" (HLB = 14), "KF-642" (HLB = 12), "KF-643" (HLB = 14), "KF-644" (HLB = 11), and "KF-6204" (HLB = 10).

[0188] Examples of the both-end non-reactive silicone oils include polyether-modified types of both-end non-reactive silicone oils. Examples of these commercially available products include various silicone oils commercially available as both-end non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. In particular, polyether-modified types of both-end non-reactive silicone oils such as "KF-6004" manufactured by Shin-Etsu Chemical Co., Ltd. can be preferably adopted.

[0189] In addition to the above, conventionally known and any suitable silicone-based additives can be adopted as the silicone-based additives. Examples of such silicone-based additives include siloxane bond-containing polymers other than those described above, hydroxyl group-containing silicone-based compounds other than those described above, and crosslinkable functional group-containing silicone-based compounds other than those described above.

[0190] Examples of commercially available siloxane bond-containing polymers other than those described above include products with trade names such as "LE-302" (manufactured by Kyoeisha Chemical Co., Ltd.), leveling agents of the BYK series manufactured by BYK-Chemie Japan Co., Ltd. ("BYK-300", "BYK-301 / 302", "BYK-306", "BYK-307", "BYK-310", "BYK-315", "BYK-313", "BYK-320", "BYK-322", "BYK-323", "BYK-325", "BYK-330", "BYK-331", "BYK-333", "BYK-337", "BYK-341", "BYK-344", "BYK-345 / 346", "BYK-347", "BYK-348", "BYK-349", "BYK-370", "BYK-375", "BYK-377", "BYK-378", "BYK-UV3500", "BYK-UV3510", "BYK-UV3570", "BYK-3550", "BYK-SILCLEAN3700", "BYK-SILCLEAN3720", etc.), leveling agents of the AC series manufactured by Algin Chemie ("AC FS180", "AC FS360", "AC S20", etc.), leveling agents of the Polyflow series manufactured by Kyoeisha Chemical Co., Ltd. ("Polyflow KL-400X", "Polyflow KL-400HF", "Polyflow KL-401", "Polyflow KL-402", "Polyflow KL-403", "Polyflow KL-404", etc.), leveling agents of the KP series manufactured by Shin-Etsu Chemical Co., Ltd. ("KP-323", "KP-326", "KP-341", "KP-104", "KP-110", "KP-112", etc.), and leveling agents manufactured by Toray Dow Corning Co., Ltd. ("LP-7001", "LP-7002", "8032ADDITIVE", "57ADDITIVE", "L-7604", "FZ-2110", "FZ-2105", "67ADDITIVE", "8618ADDITIVE", "3ADDITIVE", "56ADDITIVE", etc.).

[0191] Examples of commercially available hydroxyl group-containing silicones other than those described above include "BYK-370", "BYK-SILCLEAN3700", and "BYK-SILCLEAN3720" manufactured by BYK Chemie Japan Co., Ltd.

[0192] Examples of commercially available crosslinkable functional group-containing silicone compounds other than those described above include "BY16-855", "SF8413", "BY16-839", "SF8421", "BY16-750", "BY16-880", and "BY16-152C" manufactured by Toray Dow Corning Co., Ltd.

[0193] 〔Antioxidant〕 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 and the like. The antioxidant may be only one kind or two or more kinds.

[0194] The content ratio of the antioxidant in the urethane-based pressure-sensitive adhesive composition can adopt any appropriate content ratio within a range that does not impair the effects of the present invention. Such a content ratio, as the content ratio of the antioxidant with respect to a total of 100 parts by weight of the above urethane prepolymer and polyol, is preferably 0.01 part by weight to 10 parts by weight or more, more preferably 0.05 part by weight to 5 parts by weight, still more preferably 0.1 part by weight to 3 parts by weight, and particularly preferably 0.2 part by weight to 1 part by weight. More specifically, when the urethane-based pressure-sensitive adhesive composition is in the aspect of (A) above, since the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyol, the content ratio of the antioxidant is as described above. Also, when the urethane-based pressure-sensitive adhesive composition is in the aspect of (B) above, since the urethane-based pressure-sensitive adhesive composition does not contain a polyol (i.e., it is 0 part by weight), the range of the content ratio of the antioxidant with respect to 100 parts by weight of the urethane prepolymer is as described above. In addition, when the urethane-based pressure-sensitive adhesive composition is in the above-described aspect (C), since the urethane-based pressure-sensitive adhesive composition does not contain a urethane prepolymer (i.e., it is 0 parts by weight), the content ratio of the antioxidant to 100 parts by weight of the polyol is as described above.

[0195] Examples of the antioxidant include radical chain inhibitors, peroxide decomposers, and the like.

[0196] Examples of the radical chain inhibitor include phenolic antioxidants, amine antioxidants, and the like.

[0197] Examples of the peroxide decomposer include sulfur-based antioxidants, phosphorus-based antioxidants.

[0198] Examples of the phenolic antioxidant include monophenolic antioxidants, bisphenolic antioxidants, and polymer-type phenolic antioxidants.

[0199] Examples of the monophenolic antioxidant include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl) propionate.

[0200] Examples of the bisphenolic antioxidant 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), 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.

[0201] Examples of the polymer-type 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 tocopherol.

[0202] Examples of the sulfur-based antioxidants include dilauryl 3,3’-thiodipropionate, dimyristyl 3,3’-thiodipropionate, and distearyl 3,3’-thiodipropionate.

[0203] Examples of the phosphorus-based antioxidants include triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite.

[0204] [UV Absorbent] From the viewpoint of suppressing the deterioration of the urethane-based pressure-sensitive adhesive layer, etc., the urethane-based pressure-sensitive adhesive composition may contain a UV absorbent as another component. The UV absorbent may be only one kind or two or more kinds.

[0205] The content ratio of the UV absorbent in the urethane-based pressure-sensitive adhesive composition can adopt any appropriate content ratio as long as the effects of the present invention are not impaired. Such a content ratio, as the content ratio of the UV absorbent with respect to the total 100 parts by weight of the above urethane prepolymer and polyol, is preferably 0.01 part by weight to 10 parts by weight or more, more preferably 0.05 part by weight to 5 parts by weight, still more preferably 0.1 part by weight to 3 parts by weight, and particularly preferably 0.2 part by weight to 1 part by weight. More specifically, when the urethane-based pressure-sensitive adhesive composition is in the above-described aspect (A), since the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyol, the content ratio of the ultraviolet absorber is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above-described aspect (B), since the urethane-based pressure-sensitive adhesive composition does not contain a polyol (i.e., it is 0 parts by weight), the range of the content ratio of the ultraviolet absorber with respect to 100 parts by weight of the urethane prepolymer is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above-described aspect (C), since the urethane-based pressure-sensitive adhesive composition does not contain a urethane prepolymer (i.e., it is 0 parts by weight), the content ratio of the ultraviolet absorber with respect to 100 parts by weight of the polyol is as described above.

[0206] 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.

[0207] Examples of the benzophenone-based ultraviolet absorber 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.

[0208] Examples of benzotriazole-based ultraviolet absorbers 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-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.

[0209] Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

[0210] Examples of cyanoacrylate-based ultraviolet absorbers include 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate and ethyl-2-cyano-3,3'-diphenylacrylate.

[0211] [Light stabilizer] From the viewpoint of suppressing the deterioration of the urethane-based pressure-sensitive adhesive layer and the like, the urethane-based pressure-sensitive adhesive composition may contain a light stabilizer as another component. The light stabilizer may be only one kind or two or more kinds.

[0212] The content ratio of the light stabilizer in the urethane-based pressure-sensitive adhesive composition can adopt any appropriate content ratio as long as the effects of the present invention are not impaired. Such a content ratio, as the content ratio of the light stabilizer with respect to a total of 100 parts by weight of the above urethane prepolymer and polyol, is preferably 0.01 part by weight to 10 parts by weight or more, more preferably 0.05 part by weight to 5 parts by weight, still more preferably 0.1 part by weight to 3 parts by weight, and particularly preferably 0.2 part by weight to 1 part by weight. More specifically, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (A), since the urethane-based pressure-sensitive adhesive composition contains a urethane prepolymer and a polyol, the content ratio of the light stabilizer is as described above. Further, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (B), since the urethane-based pressure-sensitive adhesive composition does not contain a polyol (i.e., it is 0 part by weight), the range of the content ratio of the light stabilizer with respect to 100 parts by weight of the urethane prepolymer is as described above. Moreover, when the urethane-based pressure-sensitive adhesive composition is in the above aspect (C), since the urethane-based pressure-sensitive adhesive composition does not contain a urethane prepolymer (i.e., it is 0 part by weight), the content ratio of the light stabilizer with respect to 100 parts by weight of the polyol is as described above.

[0213] Examples of the light stabilizer include hindered amine light stabilizers and ultraviolet stabilizers.

[0214] 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-piperidyl sebacate.

[0215] Examples of the UV stabilizer include nickel bis(octylphenyl)sulfide, [2,2'-thiobis(4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-tert-butyl-4-hydroxybenzyl-phosphoric acid monoethyl ester, nickel-dibutyldithiocarbamate, benzoate type quencher, and nickel-dibutyldithiocarbamate.

[0216] 〔Fatty acid ester〕 From the viewpoint of improving the wettability of the urethane-based adhesive layer, etc., the urethane-based adhesive composition may contain a fatty acid ester as another component. The fatty acid ester may be only one kind or two or more kinds.

[0217] The number average molecular weight Mn of the fatty acid ester is preferably 200 to 400, more preferably 210 to 395, still 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 rate can be further improved. If the number average molecular weight Mn of the fatty acid ester is too small, the wetting rate may not improve even if the number of added parts is large. If the number average molecular weight Mn of the fatty acid ester is too large, the curability of the adhesive during drying may deteriorate, and there is a risk of not only affecting the wetting properties but also other adhesive properties.

[0218] As the fatty acid ester, any appropriate fatty acid ester can be employed as long as the effects of the present invention are not impaired. 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, methyl coconut fatty acid, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, isotridecyl stearate, triglyceride 2-ethylhexanoate, butyl laurate, and octyl oleate.

[0219] ≪1-3. Substrate layer≫ As the thickness of the substrate layer, any appropriate thickness can be adopted according to 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.

[0220] The substrate layer may be a single layer or a laminate of two or more layers. The substrate layer may be stretched.

[0221] As the material of the substrate layer, any appropriate material can be adopted according to the application. Examples include plastics, paper, metal films, non-woven fabrics, etc. Preferably, it is plastic. The substrate layer may be composed of one type of material or two or more types of materials. For example, it may be composed of two or more types of plastics.

[0222] Examples of the plastic include polyester resins, polyamide resins, and polyolefin resins. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of the polyolefin resin include homopolymers of olefin monomers and copolymers of olefin monomers. Specifically, examples of the polyolefin resin include homopolypropylene; propylene copolymers such as block, random, and graft types having an ethylene component as a copolymer component; reactor TPO; ethylene polymers such as low density, high density, linear low density, and ultra-low density; ethylene copolymers such as ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methacrylic acid copolymer, and ethylene-methyl methacrylate copolymer.

[0223] The base layer may contain any suitable additive as required. Examples of the additive that may be contained in the base layer include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, number, and amount of the additive that may be contained in the base layer can be appropriately set according to the purpose. In particular, when the material of the base layer is plastic, it is preferable to contain some of the above additives for the purpose of preventing deterioration and the like. From the viewpoint of improving weather resistance and the like, particularly preferable additives include antioxidants, ultraviolet absorbers, light stabilizers, and fillers.

[0224] Any suitable antioxidant can be employed as the antioxidant. Examples of such antioxidants include phenolic antioxidants, phosphorus-based processing heat stabilizers, lactone-based processing heat stabilizers, sulfur-based heat stabilizers, and phenol-phosphorus-based antioxidants. The content ratio of the antioxidant is preferably 1% by weight or less, more preferably 0.5% by weight or less, and still more preferably 0.01% to 0.2% by weight based on the base resin of the base layer (when the base layer is a blend, the blend is the base resin).

[0225] As the ultraviolet absorber, any suitable ultraviolet absorber can be employed. Examples of such ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and the like. The content ratio of the ultraviolet absorber is preferably 2% by weight or less, more preferably 1% by weight or less, and even more preferably 0.01% by weight to 0.5% by weight based on the base resin forming the base material layer (when the base material layer is a blend, the blend is the base resin).

[0226] As the light stabilizer, any suitable light stabilizer can be employed. Examples of such light stabilizers include hindered amine-based light stabilizers, benzoate-based light stabilizers, and the like. The content ratio of the light stabilizer is preferably 2% by weight or less, more preferably 1% by weight or less, and even more preferably 0.01% by weight to 0.5% by weight based on the base resin forming the base material layer (when the base material layer is a blend, the blend is the base resin).

[0227] As the filler, any suitable filler can be employed. Examples of such fillers include inorganic fillers. Specific examples of the inorganic filler include carbon black, titanium oxide, zinc oxide, and the like. The content ratio of the filler is preferably 20% by weight or less, more preferably 10% by weight or less, and even more preferably 0.01% by weight to 10% by weight based on the base resin forming the base material layer (when the base material layer is a blend, the blend is the base resin).

[0228] Furthermore, as additives, for the purpose of imparting antistatic properties, inorganic, low molecular weight, and high molecular weight antistatic agents such as surfactants, inorganic salts, polyhydric alcohols, metal compounds, and carbon are also preferably mentioned. In particular, from the viewpoints of contamination and maintaining adhesiveness, high molecular weight antistatic agents and carbon are preferable.

[0229] ≪≪2. Manufacturing method of the surface protection film≫≫ The surface protection film of the present invention can be manufactured by any suitable method. Such manufacturing methods include, for example, (1) A method of applying a solution or a hot melt of a material for forming an adhesive layer onto a base material layer, (2) A method of transferring an adhesive layer applied and formed in a separator shape onto a base material layer accordingly, (3) A method of extruding and forming an application of a material for forming an adhesive layer onto a base material layer, (4) A method of extruding a base material layer and an adhesive layer in two or more layers, (5) A method of single-layer laminating an adhesive layer onto a base material layer or a method of two-layer laminating an adhesive layer together with a laminate layer, (6) A method of two-layer or multi-layer laminating an adhesive layer and a base material layer forming material such as a film or a laminate layer, etc., and can be carried out according to any suitable manufacturing method.

[0230] As the coating method, for example, a roll coater method, a comma coater method, a die coater method, a reverse coater method, a silk screen method, a gravure coater method, etc. can be used.

[0231] ≪≪3. Use of the surface protection film≫≫ The surface protection film according to the embodiment of the present invention can be used for any suitable application. Since the surface protection film of the present invention is provided with a urethane-based adhesive layer having an excellent surface elastic modulus, it is preferably used for surface protection of optical members and electronic members. Examples of optical members include touch panels using LCDs, LCDs, color filters used for LCDs, polarizing plates, etc.

[0232] For a member to which the surface protection film according to the embodiment of the present invention is adhered, for example, an optical member or an electronic member, it is possible to manually bond and peel the adhered surface protection film multiple times.

[0233] That is, the optical member according to the embodiment of the present invention has the surface protection film of the present invention adhered thereto. Also, the electronic member according to the embodiment of the present invention has the surface protection film of the present invention adhered thereto.

Example

[0234] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples in any way. The test and evaluation methods in the examples and the like are as follows. When described as "part", it means "part by weight" unless otherwise specified, and when described as "%", it means "% by weight" unless otherwise specified.

[0235] <Adhesion to glass> The surface protection film (width 25 mm × length 140 mm) from which the separator was peeled off was adhered to glass (soda lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2 kg hand roller once back and forth. Then, it was left at an environmental temperature of 23°C for 30 minutes. The obtained evaluation sample was measured with a tensile tester. As the tensile tester, the product name "Autograph AG-Xplus HS 6000 mm / min high-speed model (AG-50NX plus)" manufactured by Shimadzu Corporation was used. After setting the evaluation sample in the tensile tester, the tensile test was started. The conditions of the tensile test were a peeling angle = 180 degrees and a peeling speed (tensile speed) = 300 mm / min. The load when peeling the surface protection film from the glass was measured, and the average load at that time was defined as the adhesion to glass (peeling force) of the surface protection film.

[0236] <Residual adhesion rate to glass> A surface protection film was laminated onto a glass plate (manufactured by Matsunami Glass Industry Co., Ltd., 1.35 mm × 10 cm × 10 cm) over the entire surface using a hand roller, and after storing it for 24 hours in an atmosphere of 23°C and 55% RH, the surface protection film was peeled off at a peeling angle of 180 degrees and a speed of 0.3 m / min, and a 19-mm wide No. 31B tape (manufactured by Nitto Denko Corporation, base material thickness: 25 μm) cut to a length of 150 mm was attached by reciprocating a 2.0-kg roller once in an atmosphere of 23°C and 55% RH. After curing for 30 minutes in an atmosphere of 23°C and 55% RH, a tensile testing machine (trade name "Autograph AG-Xplus HS 6000 mm / min high-speed model (AG-50NX plus)" manufactured by Shimadzu Corporation) was used to peel it at a peeling angle of 180 degrees and a pulling speed of 300 mm / min, and the adhesive strength was measured. Separately, for a glass plate that has not been treated as described above, the adhesive strength of a 19-mm wide No. 31B tape was similarly measured, and the residual adhesion rate was calculated using the following formula. Residual adhesion rate (%) = (No. 31B adhesive strength to the glass plate after peeling the surface protection film / No. 31B adhesive strength to the glass plate) × 100 This residual adhesion rate serves as an index of the degree to which the adhesive component of the surface protection film has been transferred and contaminated on the surface of the adherend. The higher the value of the residual adhesion rate, the better the surface protection film that does not contaminate the adherend, and the lower the value of the residual adhesion rate, the more the surface of the adherend is contaminated with the adhesive component or the like.

[0237] <Glass peel-off charging voltage> The surface protection film with the separator peeled off was cut into a size of 70 mm in width and 100 mm in length, and on the surface of glass (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.), with one end of the surface protection film protruding 30 mm from the end of the adherend, it was pressure-bonded with a hand roller. After leaving this sample in an environment of 23°C × 50% RH for 1 day, it was set at a predetermined position on a sample fixing base with a height of 20 mm. The end of the surface protection film protruding 30 mm from the adherend was fixed to an automatic winding machine (not shown), and peeled off so that the peeling angle = 150° and the peeling speed = 30 m / min. The potential on the surface of the adherend generated at this time was measured as the "peeling charging voltage" with a potential measuring device (manufactured by Shishido Electrostatic Co., Ltd., model "STATIRON DZ-4") fixed at a position 30 mm in height from the center of the adherend. The measurement was carried out in an environment of 23°C and 50% RH.

[0238] <Haze> The urethane-based adhesive composition was coated and dried under the conditions of Examples and Comparative Examples on the release-treated surface of a 75-μm-thick polyester film (trade name: Diafoil MRF75, manufactured by Mitsubishi Chemical Corporation) with one side release-treated with silicone to form a urethane-based adhesive layer. Next, on the surface of the urethane-based adhesive layer, a 75-μm-thick polyester film (trade name: Diafoil MRE75, manufactured by Mitsubishi Chemical Corporation) with one side release-treated with silicone was coated so that the release-treated surface of the polyester film was on the urethane-based adhesive layer side, and aged at room temperature for 5 days. Two pieces of cardboard with a size of 50 mm × 50 mm and a 20 mm × 20 mm hole in the center were prepared. After sticking the sample alone to one of them with a hand roller for one round trip, the other one was stuck. The haze of the evaluation sample obtained as described above was measured with "HM-150N" manufactured by Murakami Color Technology Research Institute.

[0239] <Surface Elastic Modulus of Adhesive Layer> The surface protection film with the separator peeled off was cut into a size of 10 mm square and fixed to a sample stage, and the elastic modulus (MPa) of the adhesive surface was measured using a nanoindenter "TI950 TriboIndenter" manufactured by Hysitron Inc. and a spherical diamond indenter with a curvature radius of 10 μm (Conical indenter). The measurement conditions are shown below. · Measurement mode: Single indentation test · Holding time when reaching the maximum displacement: 0 seconds · Indentation / extraction depth rate: 500 nm / sec · Indentation depth: 5 μm · Measurement environment: 23°C 50% RH

[0240] 〔Production Example 1〕: Production of urethane prepolymer solution A Into 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 stir bar, and stirring blades, 333 g of polytetramethylene glycol (product name "PTMG3000", manufactured by Mitsubishi Chemical Corporation), 83 g of polypropylene glycol (product name "Sunnex GP-1500", manufactured by Sanyo Chemical Industries, Ltd.), and 110 g of ethyl acetate (manufactured by Tosoh Corporation) as a solvent were added. While stirring, 0.041 g of dibutyltin dilaurate(IV) (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a catalyst, and nitrogen substitution was carried out at room temperature for 1 hour. Then, while stirring under a nitrogen flow, 13.0 g of hexamethylene diisocyanate (a polyfunctional isocyanate compound, product name "HDI", manufactured by Tosoh Corporation) was added, and the solution temperature in the experimental apparatus was controlled to be 90 ± 2°C in a water bath and held for 4 hours to obtain urethane prepolymer solution A. During the polymerization, ethyl acetate was appropriately dropped to prevent a decrease in stirrability due to temperature control during polymerization and an increase in viscosity. The total amount of ethyl acetate dropped was 320 g. The solid content concentration of urethane prepolymer solution A was 50% by weight. This urethane prepolymer A was used in the examples.

[0241] 〔Production Example 2〕: Production of urethane prepolymer solution B An experimental apparatus for polymerization equipped with a 1L round-bottom separable flask, a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirrer, and stirring blades was charged with 197 g of polypropylene glycol (product name "Sunnex 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 dilaurate (IV) (manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst. While stirring, nitrogen substitution was carried out at room temperature for 1 hour. Then, while stirring under a nitrogen flow, 33.5 g of hexamethylene diisocyanate (a polyfunctional isocyanate compound, product name "HDI", manufactured by Tosoh Corporation) was added. While controlling the solution temperature in the experimental apparatus to be 90 ± 2 °C using a water bath, it was held for 4 hours. Then, 44 g of polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Industries, Ltd.) was added. While controlling the solution temperature in the experimental apparatus to be 90 ± 2 °C using a water bath, it was held for 2 hours. Then, 25.4 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added. While controlling the solution temperature in the experimental apparatus to be 90 ± 2 °C using a water bath, it was held for 2 hours to obtain a urethane prepolymer solution B. During the polymerization, toluene was appropriately added dropwise to prevent a decrease in stirrability due to temperature control during polymerization and an increase in viscosity. The total amount of toluene added dropwise was 380 g. The solid content concentration of the urethane prepolymer solution B was 50% by weight. This urethane prepolymer B was used in the examples and comparative examples.

[0242] 〔Example 1〕 100 parts by weight of urethane prepolymer A, 3.2 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content became 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness became 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of the urethane-based adhesive (1). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having one surface silicone-treated was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (1). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0243] [Example 2] 95 parts by weight of urethane prepolymer A, 3.5 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 1.5 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 3.8 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (2). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having one surface silicone-treated was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (2). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0244] [Example 3] 95 parts by weight of urethane prepolymer A, 3 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 2 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 3.9 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Naccem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (3). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (3). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0245] 〔Example 4〕 80 parts by weight of urethane prepolymer A, 12 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 8 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 6.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (4). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (4). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0246] 〔Example 5〕 60 parts by weight of urethane prepolymer A, 28 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 12 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 8.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Naccem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness would be 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (5). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one side was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (5). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 1.

[0247] 〔Example 6〕 60 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 8.6 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Naccem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (6). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (6). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 1.

[0248] [Example 7] 50 parts by weight of urethane prepolymer A, 35 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 9.2 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 ° C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (7). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (7). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0249] 〔Example 8〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP4000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 4000), a polyol having 3 hydroxyl groups, 8.7 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (8). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (8). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0250] 〔Example 9〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (9). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (9). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 1.

[0251] 〔Example 10〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 5 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1000), a polyol having 3 hydroxyl groups, 12.9 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (10). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated on the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (10). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 1.

[0252] 〔Example 11〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 2 parts by weight of Sannix GP600 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 600), a polyol having 3 hydroxyl groups, 12.7 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (11). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having one surface silicone-treated was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (11). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0253] 〔Example 12〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 2 parts by weight of Sannix GP400 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 400), a polyol having 3 hydroxyl groups, 14.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (12). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (12). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 1.

[0254] 〔Example 13〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.05 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi 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 Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (13). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated on the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (13). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0255] [Example 14] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.1 parts by weight of 1-ethyl-3-methylimidazolium tris(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 Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (14). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated with the silicone-treated surface on the surface of the obtained adhesive layer to obtain a surface protection film (14). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0256] 〔Example 15〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(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 Narsem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (15). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated with the silicone-treated surface on the surface of the obtained adhesive layer to obtain a surface protection film (15). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0257] 〔Example 16〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 1.0 part by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 part by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 part by weight of Narsem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (16). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (16). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 2.

[0258] 〔Example 17〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 5 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1000), a polyol having 3 hydroxyl groups, 12.8 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi 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 Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (17). Next, a silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated on the surface of the obtained adhesive layer to obtain a surface protection film (17). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0259] [Example 18] 50 parts by weight of urethane prepolymer A, as polyols, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having 3 hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having 3 hydroxyl groups, 2 parts by weight of Sannix GP600 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 600), which is a polyol having 3 hydroxyl groups, 12.7 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(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 Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (18). Next, a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (18). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 2.

[0260] [Example 19] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 2 parts by weight of Sannix GP400 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 400), a polyol having 3 hydroxyl groups, 13.8 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(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 Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (19). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (19). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 2.

[0261] 〔Example 20〕 50 parts by weight of urethane prepolymer A, 35 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 9.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi 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 Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (20). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (20). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0262] [Example 21] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.05 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of Megafac F-477 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narseum No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based pressure-sensitive adhesive solution. Then, the urethane-based pressure-sensitive adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based pressure-sensitive adhesive (21). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated on the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (21). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0263] 〔Example 22〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.1 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of Megafac F-477 (manufactured by DIC Corporation) of a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (22). Next, a silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (22). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0264] [Example 23] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of Megafac F-477 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based pressure-sensitive adhesive solution. Then, the urethane-based pressure-sensitive adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based pressure-sensitive adhesive (23). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (23). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 2.

[0265] 〔Example 24〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 1.0 part by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 part by weight of Megafac F-477 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 part by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 part by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based pressure-sensitive adhesive solution. Then, the urethane-based pressure-sensitive adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based pressure-sensitive adhesive (24). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (24). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0266] [Example 25] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.05 parts by weight of Megafac F-477 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (25). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been silicone-treated on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (25). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0267] [Example 26] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Megafac F-477 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based pressure-sensitive adhesive solution. Then, the urethane-based pressure-sensitive adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and cured and dried under the conditions of a drying temperature of 130 ° C and a drying time of 3 minutes to produce a pressure-sensitive adhesive layer composed of a urethane-based pressure-sensitive adhesive (26). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (26). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0268] [Example 27] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 1.0 part by weight of Megafac F-477 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 part by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 part by weight of Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (27). Next, a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was laminated on the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (27). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0269] [Example 28] 50 parts by weight of urethane prepolymer A, 35 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 9.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of Megafac F-477 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (28). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (28). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 2.

[0270] [Example 29] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.05 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based pressure-sensitive adhesive solution. Then, the urethane-based pressure-sensitive adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce a pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive (29). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (29). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0271] [Example 30] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (30). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having one surface silicone-treated was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (30). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 3.

[0272] 〔Example 31〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (31). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (31). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0273] [Example 32] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 1.0 part by weight of Megafac F-563 (manufactured by DIC Corporation) of a fluorine-based oligomer, 0.5 part by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 part by weight of Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based pressure-sensitive adhesive solution. Then, the urethane-based pressure-sensitive adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based pressure-sensitive adhesive (32). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (32). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0274] 〔Example 33〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Megafac F-569 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (33). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having one surface silicone-treated was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (33). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 3.

[0275] [Example 34] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Megafac F-552 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (34). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (34). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0276] 〔Example 35〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Megafac F-559 (manufactured by DIC Corporation) of a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narseum ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content became 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness became 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (35). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having one surface silicone-treated was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (35). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0277] [Example 36] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.5 parts by weight of Megafac F-556 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer made of a urethane-based adhesive (36). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (36). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0278] 〔Example 37〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-containing reactive silicone oil X-22-4015 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 ° C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (37). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (37). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0279] [Example 38] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-containing reactive silicone oil KF6001 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (38). Next, a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (38). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 3.

[0280] [Example 39] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 part by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 part by weight of hydroxyl group-containing reactive silicone oil KF6002 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 part by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 part by weight of narcem ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 ° C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (39). Next, a silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated on the surface of the obtained adhesive layer to obtain a surface protection film (39). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 3.

[0281] 〔Example 40〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-containing reactive silicone oil KF6028 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (40). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having one surface silicone-treated was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (40). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 4.

[0282] 〔Example 41〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-free non-reactive silicone oil KF643 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (41). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated on the surface of the obtained adhesive layer to obtain a surface protection film (41). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 4.

[0283] [Example 42] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (42). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (42). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 4.

[0284] [Example 43] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (43). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (43). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 4.

[0285] [Example 44] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-free non-reactive silicone oil KF352A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (44). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been silicone-treated on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (44). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 4.

[0286] 〔Example 45〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl group-free non-reactive silicone oil KF945 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 ° C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (45). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been silicone-treated on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (45). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 4.

[0287] 〔Example 46〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.05 parts by weight of hydroxyl group-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (46). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (46). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 4.

[0288] [Example 47] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.025 parts by weight of hydroxyl group-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based pressure-sensitive adhesive solution. Then, the urethane-based pressure-sensitive adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 ° C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based pressure-sensitive adhesive (47). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been silicone-treated on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (47). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 4.

[0289] [Example 48] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.01 parts by weight of hydroxyl group-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (48). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (48). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 4.

[0290] 〔Example 49〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 part by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.1 part by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.025 part by weight of hydroxyl group-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 part by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 part by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness would be 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (49). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (49). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 4.

[0291] 〔Example 50〕 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness would be 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (50). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated with the silicone-treated surface on the surface of the obtained adhesive layer to obtain a surface protection film (50). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 4.

[0292] [Example 51] 50 parts by weight of urethane prepolymer A, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having 3 hydroxyl groups, 20 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), which is a polyol having 3 hydroxyl groups, 8.4 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness would be 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (51). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (51). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 5.

[0293] [Example 52] 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), which is a polyol having 3 hydroxyl groups, 9.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (52). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (52). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0294] [Example 53] 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 7.2 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (53). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (53). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0295] [Example 54] 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 6.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (54). Next, a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (54). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0296] [Example 55] 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 4.8 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (55). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was laminated onto the surface of the obtained adhesive layer to obtain a surface protection film (55). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 5.

[0297] [[Example 56]] 70 parts by weight of urethane prepolymer A, 20 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 10 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 4.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem No. 2 Iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (56). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (56). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 5.

[0298] [Example 57] 50 parts by weight of urethane prepolymer A, 24 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 26 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 6.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narseum ferric (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer made of a urethane-based adhesive (57). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated with the silicone-treated surface on the surface of the obtained adhesive layer to obtain a surface protection film (57). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0299] [Example 58] 50 parts by weight of urethane prepolymer A, 22 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 28 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 6.2 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric oxide (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (58). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (58). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0300] [Example 59] 50 parts by weight of urethane prepolymer A, 20 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 30 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 6.4 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (59). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (59). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0301] 〔Example 60〕 40 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 35 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 7.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (60). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (60). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 5.

[0302] [Example 61] 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 9.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.3 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 20 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (61). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated with the silicone-treated surface on the surface of the obtained adhesive layer to obtain a surface protection film (61). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0303] [Example 62] 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 9.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 0.5 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of narcem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 20 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (62). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been silicone-treated on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (62). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0304] [Example 63] 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 9.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 1.0 part by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 part by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 part by weight of narcem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 20 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (63). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having been subjected to silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (63). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0305] 〔Example 64〕 50 parts by weight of urethane prepolymer A, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), a polyol having 3 hydroxyl groups, 9.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 2.0 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 20 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (64). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (64). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0306] 〔Example 65〕 70 parts by weight of urethane prepolymer B, 20 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having 3 hydroxyl groups, 10 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3000), which is a polyol having 3 hydroxyl groups, 3.9 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation) of a fluorine-based oligomer, 2.0 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 20 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (65). Next, a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (65). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 5.

[0307] [Example 66] 50 parts by weight of urethane prepolymer B, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 25 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 5.9 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 2.0 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Narsem ferric chloride (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 20 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (66). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (66). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 5.

[0308] [[Example 67]] 40 parts by weight of urethane prepolymer B, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having 3 hydroxyl groups, 35 parts by weight of PTGL3000 (manufactured by Hodogaya Chemical Co., Ltd., Mn = 3,000), which is a polyol having 3 hydroxyl groups, 7.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of 1-ethyl-3-methylimidazolium tris(fluoromethanesulfonyl)imide (AS110, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an ionic compound, 0.3 parts by weight of Megafac F-563 (manufactured by DIC Corporation), a fluorine-based oligomer, 2.0 parts by weight of hydroxyl group-free non-reactive silicone oil KF640 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF SE) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 20 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (67). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (67). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 5.

[0309] [Comparative Example 1] 100 parts by weight of urethane prepolymer B, 2.9 parts by weight of a polyfunctional isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (C1). Next, a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (C1). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 6.

[0310] [Comparative Example 2] 50 parts by weight of urethane prepolymer, 35 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 9.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of Naccem No. 2 iron (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (C2). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (C2). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before evaluation. The results are shown in Table 6.

[0311] 〔Comparative Example 3〕 50 parts by weight of urethane prepolymer B, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sannix GP4000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 8.6 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness would be 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (C3). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (C3). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 6.

[0312] 〔Comparative Example 4〕 50 parts by weight of urethane prepolymer B, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 20 parts by weight of Sunnex GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 10.1 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (C4). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (C4). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 6.

[0313] 〔Comparative Example 5〕 50 parts by weight of urethane prepolymer B, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 5 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), a polyol having 3 hydroxyl groups, 12.9 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (C5). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated with the silicone-treated surface on the surface of the obtained adhesive layer to obtain a surface protection film (C5). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 6.

[0314] 〔Comparative Example 6〕 50 parts by weight of urethane prepolymer B, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 2 parts by weight of Sannix GP600 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 600), a polyol having 3 hydroxyl groups, 12.7 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a substrate made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130°C and a drying time of 3 minutes to prepare an adhesive layer made of a urethane-based adhesive (C6). Next, the silicone-treated surface of a release sheet made of a 25-μm-thick polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) having a silicone treatment on one surface was bonded to the surface of the obtained adhesive layer to obtain a surface protection film (C6). Aging was carried out at room temperature for 5 days and evaluation was performed. The release sheet was peeled off immediately before the evaluation. The results are shown in Table 6.

[0315] 〔Comparative Example 7〕 50 parts by weight of urethane prepolymer B, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), a polyol having 3 hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), a polyol having 3 hydroxyl groups, 2 parts by weight of Sannix GP400 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 400), a polyol having 3 hydroxyl groups, 13.8 parts by weight of a polyfunctional isocyanate compound (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric naphthenate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate so that the total solid content was 50% by weight to obtain a urethane-based adhesive solution. Then, the urethane-based adhesive solution was applied to a base material made of a polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the dried thickness was 75 μm, and cured and dried under the conditions of a drying temperature of 130 °C and a drying time of 3 minutes to produce an adhesive layer made of a urethane-based adhesive (C7). Next, a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a silicone treatment on one surface was laminated on the surface of the obtained adhesive layer with the silicone-treated surface to obtain a surface protection film (C7). Aging was performed at room temperature for 5 days and evaluation was carried out. The release sheet was peeled off immediately before evaluation. The results are shown in Table 6.

[0316]

Table 1

[0317]

Table 2

[0318]

Table 3

[0319]

Table 4

[0320]

Table 5

[0321]

Table 6

Industrial Applicability

[0322] The surface protection film of the present invention can be used for any suitable application. Preferably, the surface protection film of the present invention is preferably used for surface protection of optical members and electronic members.

Explanation of Reference Numerals

[0323] 1 Substrate layer 2 Adhesive layer 10 Surface protection film

Claims

1. A surface protection film comprising a urethane-based adhesive layer, wherein the urethane-based adhesive layer is composed of a urethane-based adhesive formed from a urethane-based adhesive composition, the urethane-based adhesive composition contains a urethane prepolymer, a polyol, and a polyfunctional isocyanate compound, the polyol contains a first polyol having a number average molecular weight Mn of 5000 to 20000 and a second polyol having a number average molecular weight Mn of 300 to 4999, the urethane prepolymer and / or the second polyol has a structural unit represented by the following general formula (1), the weight ratio of the total amount of the urethane prepolymer, the polyol, and the polyfunctional isocyanate compound in the urethane-based adhesive composition is 90 wt% to 100 wt%, the weight ratio of the urethane prepolymer to the polyol in the urethane-based adhesive composition is urethane prepolymer:polyol = (50 to 99):(1 to 50), the content ratio of the polyfunctional isocyanate compound in the urethane-based adhesive composition is 2.5 parts by weight to 20 parts by weight with respect to a total of 100 parts by weight of the urethane prepolymer and the polyol, the surface elastic modulus of the urethane-based adhesive layer is 0.8 MPa or more, a surface protection film. 【Chemical 1】 (In the 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. A plurality of R 1 may be the same as or different from each other. n represents an integer of 1 to 4. m is the number of repetitions of the constitutional unit and represents an integer of 1 to 200.)

2. The urethane prepolymer and / or the polyol has a structural unit represented by the following general formula (2), The surface protection film according to claim 1, wherein the content ratio of the structural unit represented by the general formula (1) in the urethane-based adhesive composition is larger than the content ratio of the structural unit represented by the general formula (2). 【Chemical Formula 2】 (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. A plurality of R 2 may be the same as or different from each other. p is the number of repetitions of the constitutional unit and represents an integer of 1 to 300.)

3. The urethane-based adhesive composition contains an ionic compound, The surface protection film according to claim 1 or 2, wherein the content ratio of the ionic compound with respect to a total of 100 parts by weight of the urethane prepolymer and the polyol is 0.05 parts by weight or more.

4. The urethane-based adhesive composition contains at least one selected from the group consisting of a fluorine-based additive and a silicone-based additive, The surface protection film according to any one of claims 1 to 3, wherein the total content ratio of the fluorine-based additive and the silicone-based additive with respect to a total of 100 parts by weight of the urethane prepolymer and the polyol is 0.01 parts by weight or more.

5. When the urethane-based pressure-sensitive adhesive layer is bonded to a glass plate and peeled off from the glass plate at a peeling angle of 180 degrees and a peeling speed of 300 mm / min after 30 minutes at 23°C, the peeling force is 0.5 gf / 25 mm to 2.0 gf / 25 mm. The surface protection film according to any one of claims 1 to 4.

6. The surface protection film according to any one of claims 1 to 5, wherein the haze of the urethane-based pressure-sensitive adhesive layer is 3.5% or less.

7. After the urethane-based pressure-sensitive adhesive layer is bonded to a glass plate and peeled off from the glass plate at a peeling angle of 180 degrees and a peeling speed of 0.3 m / min after 24 hours at 23°C, the residual adhesion rate to the glass plate is 80% or more. The surface protection film according to any one of claims 1 to 6.

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