Surface protection film

Abstract

Provided is a surface protective film capable of achieving thickening of an adhesive layer, capable of exhibiting light peeling, and capable of achieving low haze. Also provided are an optical member and an electronic member to which such a surface protective film is attached. The surface protective film of the embodiment of the present application includes a urethane-based adhesive layer composed of a urethane-based adhesive formed from a urethane-based adhesive composition including a urethane prepolymer P, a polyol A, and a polyfunctional isocyanate compound B, the weight ratio of P to A being P:A=(50-99):(1-50), the polyol A including a first polyol A1 having a number average molecular weight Mn of 5000-20000 and a second polyol A2 having a number average molecular weight Mn of 300-4999, the weight ratio of A1 to A2 being 1.0≤(A1 / A2)≤3.5.

Description

Technical Field

[0001] This invention relates to surface protective films. Background Technology

[0002] Optical and electronic components are fitted with surface protective films to prevent surface damage during processing, assembly, inspection, and transportation. These protective films are then peeled off from the optical and electronic components when surface protection is no longer required (Patent Document 1).

[0003] When optical and electronic components with such a surface protective film are to be peeled off as described above, it is important that the surface protective film can be easily peeled off only at the interface between the surface protective film and the optical or electronic component. Furthermore, when protecting displays with large height differences, such as organic EL displays, the adhesive layer needs to be thickened to match these height differences.

[0004] As an adhesive layer for such a surface protective film, adhesive layers composed of various adhesives are known. From the perspective of excellent reprocessability, wettability, and transparency, an adhesive layer composed of urethane-based adhesives is preferably used as an adhesive layer for a surface protective film adhered to optical components and electronic components.

[0005] There are two manufacturing methods for urethane-based adhesives: a one-step method that directly reacts a polyol with a polyfunctional isocyanate to manufacture the urethane adhesive without using a urethane prepolymer; and a prepolymer method that reacts a urethane prepolymer with a polyfunctional isocyanate to manufacture the urethane adhesive.

[0006] In the one-step process, polyols with a number-average molecular weight of around 10,000 are used. Therefore, direct curing via reaction with polyfunctional isocyanates results in a high crosslinking density, ensuring easy peelability. However, the adhesive solution in the one-step process has a low viscosity, making it unsuitable for thick film formation (Patent Document 2).

[0007] In the prepolymer method, the adhesive solution has a high viscosity, making it suitable for thick film formation. However, the adhesive obtained by curing through reaction with polyfunctional isocyanates in the prepolymer method has a low crosslinking density, making it difficult to ensure easy peelability. Therefore, a technique for ensuring easy peelability by combining polyols with a number average molecular weight of 300 or less has been reported (Patent Document 3).

[0008] However, when urethane prepolymers and polyols with a number average molecular weight of less than 300 are used in combination, the significant difference in their molecular weights leads to poor compatibility and increased haze in the adhesive. Increased haze not only degrades the quality of the surface protective film but also reduces its inspectability when applied to surface protective films for applications such as optical or electronic components.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2016-17109

[0012] Patent Document 2: Japanese Patent No. 5501489

[0013] Patent Document 3: Japanese Patent Application Publication No. 2018-62595 Summary of the Invention

[0014] The problem the invention aims to solve

[0015] The objective of this invention is to provide a surface protective film capable of achieving a thick adhesive layer, exhibiting light peelability, and achieving low haze. Furthermore, it also aims to provide optical and electronic components to which such a surface protective film is bonded.

[0016] Solution for solving the problem

[0017] The surface protective film of embodiments of the present invention comprises a urethane-based adhesive layer.

[0018] The urethane-based adhesive layer is composed of an urethane-based adhesive, which is formed from an urethane-based adhesive composition.

[0019] The urethane-based adhesive composition comprises urethane prepolymer P, polyol A, and polyfunctional isocyanate compound B.

[0020] The weight ratio of the urethane prepolymer P to the polyol A is P:A = (50-99):(1-50).

[0021] The polyol A comprises a first polyol A1 with a number-average molecular weight Mn of 5000–20000 and a second polyol A2 with a number-average molecular weight Mn of 300–4999.

[0022] The weight ratio of the first polyol A1 to the second polyol A2 is 1.0 ≤ (A1 / A2) ≤ 3.5.

[0023] In one embodiment, the above-mentioned urethane-based adhesive composition contains an ionic compound, and the content of the ionic compound is 0.05% by weight or more relative to the total amount of the above-mentioned urethane prepolymer P and the above-mentioned polyol A.

[0024] In one embodiment, the urethane-based adhesive composition comprises at least one selected from the group consisting of fluorinated additives and silicone additives, and the total amount of the fluorinated additive and the silicone additive is 0.01% by weight or more relative to the total amount of the urethane prepolymer P and the polyol A.

[0025] In one embodiment, the weight ratio of the first polyol A1 to the second polyol A2 is 1.0 ≤ (A1 / A2) ≤ 2.0.

[0026] In one embodiment, when the above-mentioned urethane adhesive layer is adhered to a glass plate and peeled from the glass plate at 23°C for 30 minutes at a peel angle of 180 degrees and a peel speed of 300 mm / min, the peel force is 0.5 gf / 25 mm to 2.0 gf / 25 mm.

[0027] In one embodiment, after the above-mentioned urethane-based adhesive layer is adhered to a glass plate and peeled off from the glass plate at 23°C for 24 hours at a peel angle of 180 degrees and a peel speed of 0.3 m / min, the residual adhesion rate to the glass plate is 80% or more.

[0028] The optical components of the embodiments of the present invention are bonded with the surface protective film of the embodiments of the present invention.

[0029] The electronic components of the embodiments of the present invention are bonded with the surface protective film of the embodiments of the present invention.

[0030] The effects of the invention

[0031] According to the present invention, a surface protective film capable of achieving a thick adhesive layer, exhibiting light peelability, and achieving low haze can be provided. Furthermore, optical components and electronic components with such a surface protective film bonded to them can be provided. Attached Figure Description

[0032] Figure 1 This is a cross-sectional schematic diagram of the surface protective film according to a preferred embodiment of the present invention. Detailed Implementation

[0033] <<<<1. Surface Protective Film>>>>

[0034] The surface protective film of embodiments of the present invention comprises a urethane-based adhesive layer. On the adhesive side of the urethane-based adhesive layer, any suitable release liner with mold-release properties may be adhered without impairing the effects of the present invention.

[0035] The surface protective film of embodiments of the present invention preferably comprises a substrate layer and a urethane-based adhesive layer. The substrate layer may be a single layer or two or more layers. The urethane-based adhesive layer may be a single layer or two or more layers. In addition to the substrate layer and the urethane-based adhesive layer, the surface protective film of the present invention may have any suitable other layers without impairing the effects of the present invention.

[0036] Figure 1 This is a cross-sectional schematic diagram of a surface protective film according to a preferred embodiment of the present invention. The surface protective film 10 includes a substrate layer 1 and an adhesive layer 2. The surface protective film of the present invention may further have any other suitable layers (not shown) used as needed, such as a release liner.

[0037] For the side of the substrate layer 1 where the adhesive layer 2 is not attached, for purposes such as forming a wound that is easy to unwind, for example, a release treatment can be performed by adding fatty acid amides, polyethyleneimine, long-chain alkyl additives, etc. to the substrate layer, or a coating formed by any suitable release agent such as organosilicon, long-chain alkyl, or fluorine can be applied.

[0038] Release pads that can be present on the adhesive side of a urethane-based adhesive layer include, for example, release pads obtained by treating the surface of a substrate (pad substrate) such as paper or plastic film with silicone, and release pads obtained by laminating the surface of a substrate (pad substrate) such as paper or plastic film with a polyolefin resin.

[0039] Examples of plastic films used as substrates for release liner include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene-vinyl acetate copolymer film.

[0040] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, further preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0041] The thickness of the surface protective film in embodiments of the present invention can be set to any suitable thickness depending on the application. Typically, it is preferably 10 μm to 300 μm, more preferably 15 μm to 250 μm, further preferably 20 μm to 200 μm, and particularly preferably 25 μm to 150 μm.

[0042] In the surface protective film of the embodiments of the present invention, a thick film of the urethane-based adhesive layer can be achieved. Therefore, the thickness of the urethane-based adhesive layer included in the surface protective film of the present invention is preferably 1 μm to 150 μm, more preferably 5 μm to 150 μm, further preferably 10 μm to 150 μm, further preferably 20 μm to 150 μm, further preferably 30 μm to 150 μm, further preferably 40 μm to 150 μm, further preferably 50 μm to 150 μm, particularly preferably 60 μm to 150 μm, and most preferably 65 μm to 150 μm. When the urethane-based adhesive layer can be thickened in this way, the surface protective film of the embodiments of the present invention can well follow the height difference when protecting displays with large height differences, such as organic EL displays.

[0043] The surface protective film of the present invention exhibits light peelability. When the surface protective film of the present invention, comprising a urethane-based adhesive layer, is adhered to a glass plate and then peeled from the glass plate at 23°C for 30 minutes at a peel angle of 180 degrees and a peel speed of 300 mm / min, the peel 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, further preferably 0.5 gf / 25 mm to 3.0 gf / 25 mm, particularly preferably 0.5 gf / 25 mm to 2.5 gf / 25 mm, and most preferably 0.5 gf / 25 mm to 2.0 gf / 25 mm. When the peel force is within the above range, the surface protective film of the present invention exhibits excellent light peelability.

[0044] The surface protective film of embodiments of the present invention can achieve low haze. The haze of the urethane-based adhesive layer included in the surface protective film of the present invention is preferably 4.5% or less, more preferably 4.0% or less, further preferably 3.5% or less, particularly preferably 3.0% or less, and most preferably 2.5% or less. When the haze is within the above range, the surface protective film of embodiments of the present invention can achieve excellent low haze, for example, exhibiting excellent inspectability.

[0045] The residual adhesion rate of the surface protective film of the present invention, after being adhered to a glass plate and peeled off from the glass plate at a peel angle of 180 degrees and a peel speed of 0.3 m / min at 23°C for 24 hours, is preferably 60% or more, more preferably 70% or more, further preferably 80% or more, particularly preferably 85% or more, and most preferably 90% or more. When the above-mentioned residual adhesion rate is within the above range, the surface protective film of the present invention can reduce adhesive residue.

[0046] The peeling electrostatic voltage of the surface protective film of the present invention, when its contained urethane adhesive layer is adhered to a glass plate and peeled from the glass plate at 23°C for 24 hours at a peel angle of 150 degrees and a peel speed of 30 m / min, is preferably 15 kV or less, more preferably 10 kV or less, further preferably 5 kV or less, particularly preferably 2 kV or less, and most preferably 1 kV or less. When the peeling electrostatic voltage is within the above range, the surface protective film of the present invention can effectively prevent static electricity during peeling.

[0047] <<1-1. Carbamate-based adhesive layer>>

[0048] The urethane-based adhesive layer is composed of urethane-based adhesives. The urethane-based adhesive is formed from a urethane-based adhesive composition. That is, the urethane-based adhesive formed from the urethane-based adhesive composition is formed into an adhesive layer by constituting a layer shape.

[0049] A urethane-based adhesive can be defined as a substance formed from a urethane-based adhesive composition. This is because urethane-based adhesives are formed by cross-linking reactions of urethane-based adhesive compositions through heating, ultraviolet irradiation, etc. Therefore, it is not possible to directly define a urethane-based adhesive by its structure. In addition, there are almost impractical situations ("impossible / impractical situations"). Therefore, by defining it as "a substance formed from a urethane-based adhesive composition", urethane-based adhesives are appropriately defined as a "substance".

[0050] As described above, the thickness of the urethane-based adhesive layer in the surface protective film of the present invention can be achieved by thickening the urethane-based adhesive layer. Therefore, it is preferably 1 μm to 150 μm, more preferably 5 μm to 150 μm, even more preferably 10 μm to 150 μm, even more preferably 20 μm to 150 μm, even more preferably 30 μm to 150 μm, even more preferably 40 μm to 150 μm, even more preferably 50 μm to 150 μm, particularly preferably 60 μm to 150 μm, and most preferably 65 μm to 150 μm. When the urethane-based adhesive layer can be thickened in this way, the surface protective film of the embodiments of the present invention can well follow the height difference when protecting displays with large height differences, such as organic EL displays.

[0051] The urethane-based adhesive is formed from a urethane-based adhesive composition. Any suitable forming method can be employed without impairing the effects of the present invention. Examples of such forming methods include: directly applying the urethane-based adhesive composition to any suitable substrate film (e.g., the substrate layer in the surface protective film of an embodiment of the present invention) and then drying or curing it (direct method); applying the urethane-based adhesive composition to the surface of a release liner (release surface) and then drying or curing it to form a urethane-based adhesive layer on that surface, and then bonding the urethane-based adhesive layer to a substrate film (e.g., the substrate layer in the surface protective film of an embodiment of the present invention) to transfer the urethane-based adhesive layer (transfer method). From the viewpoint of the anchoring properties of the adhesive layer, the direct method is typically preferred.

[0052] Methods for imparting such urethane-based adhesive layers (typically coating) include various conventionally known methods such as roller coating, gravure coating, reverse coating, kiss coating, dip roller coating, bar coating, roller brush coating, spraying, doctor blade coating, air knife coating, spraying, comma coating, direct coating, and coating using a die coater.

[0053] Drying of the urethane-based adhesive composition can be carried out under heating (e.g., by heating to about 60°C to 150°C) as needed. As a means of curing the urethane-based adhesive composition, ultraviolet light, laser rays, alpha rays, beta rays, gamma rays, X-rays, and electron beams may be suitable, for example.

[0054] The urethane-based adhesive composition comprises urethane prepolymer P, polyol A, and polyfunctional isocyanate compound B.

[0055] The weight ratio of the total amount of urethane prepolymer P, polyol A, and polyfunctional isocyanate compound B in the urethane-based adhesive composition is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, further preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably 98% to 100% by weight. By adjusting the weight ratio of the total amount of urethane prepolymer P and polyol A in the urethane-based adhesive composition to the above range, the surface protective film of the present invention can effectively exhibit the effects of the present invention.

[0056] In the urethane-based adhesive composition, the weight ratio of urethane prepolymer P to polyol A is preferably P:A = (50-99):(1-50), more preferably (50-90):(10-50), further preferably (50-80):(20-50), and particularly preferably (50-70):(30-50). By adjusting the weight ratio of urethane prepolymer P to polyol A in the urethane-based adhesive composition to the above range, the surface protective film of the present invention can effectively exhibit the effects of the present invention.

[0057] The equivalence ratio of NCO groups to OH groups in the urethane prepolymer P and the polyfunctional isocyanate compound B, expressed as NCO groups / OH groups, is preferably 1.0 to 2.0, more preferably 1.1 to 1.9, further preferably 1.2 to 1.8, and particularly preferably 1.2 to 1.7. By adjusting the equivalence ratio of NCO groups / OH groups to the above range, the surface protective film of the embodiments of the present invention exhibits superior wettability and superior surface contour following even when adhered to substrates with significant surface differences, thus achieving a higher and more complete adhesion rate.

[0058] The proportion of polyfunctional isocyanate compound B in the urethane-based adhesive composition relative to the weight of urethane prepolymer P100 is preferably 2.5 to 40 parts by weight, more preferably 4 to 30 parts by weight, further preferably 5 to 20 parts by weight, and particularly preferably 6 to 15 parts by weight. By adjusting the proportion of polyfunctional isocyanate compound B to the above range, the surface protective film of the embodiments of the present invention exhibits superior wettability and superior surface conformability even when adhered to substrates with significant surface differences, thus achieving a higher and more complete adhesion.

[0059] In this invention, the urethane-based adhesive constituting the urethane-based adhesive layer is not a one-step urethane-based adhesive manufactured by directly reacting a polyol and a polyfunctional isocyanate without using a urethane prepolymer, but rather a urethane-based adhesive manufactured by a prepolymer method, which involves reacting a urethane prepolymer P with a polyfunctional isocyanate compound B. Because the surface protective film of this invention has an urethane-based adhesive layer composed of such a prepolymer-based adhesive, it is possible to achieve a thicker urethane-based adhesive layer, and when protecting displays with large height differences, such as organic EL displays, it can effectively follow these height differences.

[0060] <1-1-1. Carbamate Prepolymer P>

[0061] The urethane prepolymer P is typically a polyurethane polyol, preferably formed by reacting a polyester polyol (p1) and a polyether polyol (p2) with an organic polyisocyanate compound (p3) in the presence or absence of a catalyst. It should be noted that the urethane prepolymer P can be a commercially available urethane prepolymer.

[0062] The urethane prepolymer P can be a single type or two or more types.

[0063] The number average molecular weight Mn of the urethane prepolymer P is preferably 1,000 to 100,000.

[0064] As the polyester polyol (p1), any suitable polyester polyol can be used without impairing the effects of the present invention. Examples of such polyester polyols (p1) include those obtained by reacting an acid component with a diol component. Examples of acid components include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of diol components include ethylene glycol, propylene glycol, diethylene glycol, butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentanediol, and butylethylpentanediol. Examples of polyol components include glycerol, trimethylolpropane, and pentaerythritol. In addition to these, polyester polyols (p1) can be listed as examples of polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0065] The molecular weight of the polyester polyol (p1) can range from low to high. The number average molecular weight of the polyester polyol (p1) is preferably 500 to 5000. When the number average molecular weight is less than 500, there is a concern that reactivity increases and gelation becomes more likely. When the number average molecular weight exceeds 5000, there is a concern that reactivity decreases, and consequently, the cohesive strength of the polyurethane polyol itself decreases. The amount of polyester polyol (p1) used is preferably 10 mol% to 90 mol% of the polyols constituting the urethane prepolymer P (represented by polyurethane polyols).

[0066] As the polyether polyol (p2), any suitable polyether polyol can be used without impairing the effects of the present invention. Examples of such polyether polyols (p2) include those obtained by polymerizing epoxides such as ethylene oxide, propylene oxide, butane oxide, and tetrahydrofuran using low molecular weight polyols such as water, propylene glycol, ethylene glycol, glycerol, and trimethylolpropane as initiators. Examples of such polyether polyols (p2) include polypropylene glycol, polyethylene glycol, and polytetramethylene glycol, which have two or more functional groups.

[0067] The molecular weight of the polyether polyol (p2) can range from low to high. The number average molecular weight of the polyether polyol (p2) is preferably 1000 to 5000. When the number average molecular weight is below 1000, there is a concern that reactivity increases and gelation becomes more likely. When the number average molecular weight exceeds 5000, there is a concern that reactivity decreases, and consequently, the cohesive strength of the polyurethane polyol itself decreases. The amount of polyether polyol (p2) used is preferably 20 mol% to 80 mol% of the polyol constituting the urethane prepolymer P (represented by polyurethane polyol).

[0068] Polyether polyols (p2) can be partially replaced with diols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butyl ethyl pentanediol, glycerol, trimethylolpropane, pentaerythritol, etc., as well as polyamines such as ethylenediamine, N-aminoethyl ethanolamine, isophorone diamine, phenylenediamine, etc., as needed for combined use.

[0069] As the polyether polyol (p2), only difunctional polyether polyols can be used, or a portion or all of polyether polyols with a number average molecular weight of 1000 to 5000 and having at least three hydroxyl groups per molecule can be used. When a portion or all of the polyether polyol (p2) is used with a number average molecular weight of 1000 to 5000 and having at least three hydroxyl groups per molecule, a good balance between adhesiveness and re-peelability can be achieved. With such polyether polyols (p2), if the number average molecular weight is below 1000, there is a concern that reactivity will increase and gelation will be more likely. Furthermore, with such polyether polyols (p2), if the number average molecular weight exceeds 5000, there is a concern that reactivity will decrease, and consequently, the cohesive strength of the urethane prepolymer P (representatively polyurethane polyols) will decrease. A more preferable number average molecular weight for such polyether polyols (p2) is 2500 to 3500.

[0070] As the organic polyisocyanate compound (p3), any suitable organic polyisocyanate compound may be used without impairing the effects of the present invention. Examples of such organic polyisocyanate compounds (p3) include aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates.

[0071] Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, o-anisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4”-triphenylmethane triisocyanate.

[0072] Examples of aliphatic polyisocyanates include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylidene diisocyanate, 2,3-butylidene diisocyanate, 1,3-butylidene diisocyanate, dodecamethyl diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0073] Examples of aromatic aliphatic polyisocyanates include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylphenyldimethyl diisocyanate, and 1,3-tetramethylphenyldimethyl diisocyanate.

[0074] Examples of alicyclic polyisocyanates include 3-isocyanate methyl-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'-methylene bis(cyclohexyl isocyanate), 1,4-bis(isocyanate methyl)cyclohexane, and 1,4-bis(isocyanate methyl)cyclohexane.

[0075] As an organic polyisocyanate compound (p3), it can be used in combination with trimethylolpropane adducts, biuret forms formed by reaction with water, and trimers with isocyanurate rings.

[0076] As a catalyst that can be used in the manufacture of urethane prepolymer P (representatively polyurethane polyols), any suitable catalyst can be used without impairing the effects of the present invention. Examples of such catalysts include tertiary amine compounds and organometallic compounds.

[0077] Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undec-7-ene (DBU).

[0078] As organometallic compounds, examples include tin compounds and non-tin compounds.

[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 ethanol, tributyltin ethanol, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

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

[0081] When using a catalyst in the manufacture of urethane prepolymer P (represented by polyurethane polyols), gelation and turbidity of the reaction solution can easily occur in systems containing two polyols, polyester polyol (p1) and polyether polyol (p2), due to their differences in reactivity. Therefore, by using two catalysts when obtaining urethane prepolymer P (represented by polyurethane polyols), these problems can be easily solved by controlling the reaction rate and catalyst selectivity. Examples of such combinations of two catalysts include tertiary amine / organometallic, tin / non-tin, and tin / tin, with tin / tin being preferred, and more preferably a combination of dibutyltin dilaurate and tin 2-ethylhexanoate. The mixing ratio, by weight, is preferably less than 1 for tin 2-ethylhexanoate / dibutyltin dilaurate, more preferably 0.2 to 0.6. When the mixing ratio is 1 or higher, there is a concern that gelation may easily occur due to the balance of catalytic activity.

[0082] When a catalyst is used in the manufacture of urethane prepolymer P (representatively polyurethane polyol), the amount of catalyst used is preferably 0.01% to 1.0% by weight relative to the total amount of polyester polyol (a1), polyether polyol (a2), and organic polyisocyanate compound (a3).

[0083] When a catalyst is used in the manufacture of urethane prepolymer P (typically polyurethane polyol), the reaction temperature is preferably below 100°C, more preferably 85°C to 95°C. At temperatures above 100°C, there are concerns that controlling the reaction rate and crosslinking structure becomes difficult, and that it is difficult to obtain urethane prepolymer P (typically polyurethane polyol) with a specified molecular weight.

[0084] When manufacturing urethane prepolymer P (typically polyurethane polyol), a catalyst may not be used. In this case, the reaction temperature is preferably 100°C or higher, more preferably 110°C or higher. Furthermore, when obtaining urethane prepolymer P (typically polyurethane polyol) without a catalyst, the reaction time is preferably 3 hours or more.

[0085] Methods for manufacturing urethane prepolymer P (representatively polyurethane polyols) include, for example: 1) adding polyester polyol (p1), polyether polyol (p2), catalyst, and organic polyisocyanate compound (p3) to a flask; and 2) adding polyester polyol (p1), polyether polyol (p2), and catalyst to a flask and then adding organic polyisocyanate compound (p3) dropwise. From the perspective of controlling the reaction, method 2) is preferred for manufacturing urethane prepolymer P (representatively polyurethane polyols).

[0086] In manufacturing urethane prepolymer P (representatively polyurethane polyol), any suitable solvent may be used without impairing the effects of the present invention. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Toluene is preferred among these solvents.

[0087] <1-1-2. Polyol A>

[0088] Examples of polyol A include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols. Polyester polyols and polyether polyols are more preferred as polyol A.

[0089] As a polyester polyol, it can be obtained, for example, through the esterification reaction of the polyol component and the acid component.

[0090] Examples of polyol components include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol.

[0091] Examples of acidic components include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, 1,14-tetradecanoic 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 anhydrides.

[0092] Examples of polyether polyols include those obtained by addition polymerization of epoxides such as ethylene oxide, propylene oxide, and ethylene oxide using water, low-molecular-weight polyols (propylene glycol, ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), and dihydroxybenzenes (catechol, resorcinol, hydroquinone, etc.) as initiators. Specifically, examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0093] Examples of polycaprolactone polyols include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

[0094] Examples of polycarbonate polyols include: polycarbonate polyols obtained by polycondensation of the above-mentioned polyol components with phosgene; polycarbonate polyols obtained by transesterification condensation of the above-mentioned polyol components with carbonate diesters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and dibenzyl carbonate; copolymer polycarbonate polyols obtained by combining two or more of the above-mentioned polyol components; and polycarbonate polyols obtained by esterification of the above-mentioned polycarbonate polyols with carboxyl-containing compounds. Polycarbonate polyols obtained by etherifying the above-mentioned polycarbonate polyols with hydroxyl-containing compounds; polycarbonate polyols obtained by transesterification of the above-mentioned polycarbonate polyols with ester compounds; polycarbonate polyols obtained by transesterification of the above-mentioned polycarbonate polyols with hydroxyl-containing compounds; polyester-based polycarbonate polyols obtained by polycondensation of the above-mentioned polycarbonate polyols with dicarboxylic acid compounds; and copolymer polyether-based polycarbonate polyols obtained by copolymerization of the above-mentioned polycarbonate polyols with epoxides.

[0095] Examples of castor oil-based polyols include those obtained by reacting castor oil fatty acids with the aforementioned polyol components. Specifically, examples include castor oil-based polyols obtained by reacting castor oil fatty acids with polypropylene glycol.

[0096] Polyol A comprises a first polyol A1 with a number-average molecular weight Mn of 5000 to 20000 and a second polyol A2 with a number-average molecular weight Mn of 300 to 4999. Polyol A further exhibits the effects of the present invention by comprising the first polyol A1 with a number-average molecular weight Mn of 5000 to 20000 and the second polyol A2 with a number-average molecular weight Mn of 300 to 4999.

[0097] The first polyol A1 can be a single type or two or more types.

[0098] The second polyol A2 can be only one type or more than two types.

[0099] The total content of the first polyol A1 and the second polyol A2 in polyol A is preferably 80% to 100% by weight, more preferably 90% to 100% by weight, further preferably 95% to 100% by weight, particularly preferably 98% to 100% by weight, and most preferably substantially 100% by weight, from the viewpoint that this can further demonstrate the effects of the present invention.

[0100] The number-average molecular weight Mn of the first polyol A1 is 5000-20000, preferably 6000-18000, more preferably 7000-16000, further preferably 8000-15000, and particularly preferably 9000-14000. When the number-average molecular weight Mn of the first polyol A1 is within the above range, the effects of the present invention can be further exhibited.

[0101] The number-average molecular weight Mn of the second polyol A2 is 300–4999, preferably 350–4500, more preferably 400–4000, further preferably 500–3800, and particularly preferably 700–3500. When the number-average molecular weight Mn of the second polyol A2 is within the above range, the effects of the present invention can be further demonstrated.

[0102] The weight ratio of the first polyol A1 to the second polyol A2 is preferably 1.0 ≤ (A1 / A2) ≤ 3.5, more preferably 1.0 ≤ (A1 / A2) ≤ 3.0, even more preferably 1.0 ≤ (A1 / A2) ≤ 2.5, and particularly preferably 1.0 ≤ (A1 / A2) ≤ 2.0. When the weight ratio of the first polyol A1 to the second polyol A2 is within the above range, the effects of the present invention can be further exhibited.

[0103] From the viewpoint that the first polyol A1 can further demonstrate the effects of the present invention, it preferably has 3 to 6 OH groups, more preferably 3 to 5, further preferably 3 to 4, and particularly preferably 3.

[0104] From the viewpoint that the first polyol A1 can further demonstrate the effects of the present invention, it is preferred to contain 50% to 100% by weight of a triol with 3 OH groups, more preferably 70% to 100% by weight, further preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably substantially 100% by weight.

[0105] From the viewpoint that the second polyol A2 can further demonstrate the effects of the present invention, it preferably has 3 to 6 OH groups, more preferably 3 to 5, further preferably 3 to 4, and particularly preferably 3.

[0106] From the viewpoint that the second polyol A2 can further demonstrate the effects of the present invention, it is preferred to contain 50% to 100% by weight of a triol with 3 OH groups, more preferably 70% to 100% by weight, further preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably substantially 100% by weight.

[0107] <1-1-3. Polyfunctional isocyanate compound B>

[0108] The polyfunctional isocyanate compound B can be only one type or two or more types.

[0109] As the polyfunctional isocyanate compound B, any suitable polyfunctional isocyanate compound that can be used in carbamate reactions can be adopted. Examples of such polyfunctional isocyanate compounds B include polyfunctional aliphatic isocyanates, polyfunctional alicyclic isocyanates, and polyfunctional aromatic isocyanates.

[0110] Examples of polyfunctional aliphatic isocyanate compounds include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylidene diisocyanate, 1,3-butylidene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0111] Examples of polyfunctional alicyclic isocyanate compounds include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated phenylenedimethylene diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated tetramethylphenylenedimethylene diisocyanate.

[0112] Examples of polyfunctional aromatic diisocyanate compounds include phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene 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 phenylenediamine diisocyanate.

[0113] As for polyfunctional isocyanate compound B, examples include trimethylolpropane adducts of various polyfunctional isocyanate compounds as described above, biuret forms formed by reaction with water, and trimers having isocyanurate rings. Furthermore, they can be used in combination.

[0114] <1-1-4. Other Ingredients>

[0115] In addition to urethane prepolymer P, polyol A, and polyfunctional isocyanate compound B, the urethane-based adhesive composition may contain any suitable other components without impairing the effects of the present invention. Such other components may include, for example, resin components other than urethane prepolymer P and polyol A, crosslinking agents other than polyfunctional isocyanate compound B, crosslinking delay agents, ionic compounds, fluorinated additives, silicone 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.

[0116] [Ionic compounds]

[0117] When ionic compounds are included as other components, the antistatic properties of the surface protective film in embodiments of the present invention can be improved.

[0118] The proportion of the ionic compound can be any appropriate proportion without impairing the effects of the present invention. From the viewpoint of further improving the antistatic properties of the surface protective film of the present invention, the proportion of the ionic compound relative to the total amount of urethane prepolymer P and polyol A is preferably 0.05% by weight or more, more preferably 0.10% by weight to 50% by weight, further preferably 0.20% by weight to 30% by weight, particularly preferably 0.30% by weight to 10% by weight, and most preferably 0.50% by weight to 1% by weight. When the proportion of the ionic compound relative to the total amount of urethane prepolymer P and polyol A is within the above range, the antistatic properties of the surface protective film of the present invention can be further improved. If the proportion of the ionic compound relative to the total amount of urethane prepolymer P and polyol A deviates from the above range and is too low, there is a concern that the surface protective film of the present invention may not be able to impart sufficient antistatic properties. When the proportion of ionic compounds deviates excessively from the above range relative to the total amount of urethane prepolymer P and polyol A, there is a concern about increased contamination of the adhered material.

[0119] As an ionic compound, any suitable ionic compound may be used without impairing the effects of the present invention. There may be only one ionic compound or two or more ionic compounds.

[0120] From the viewpoint that the effects of the present invention can be further demonstrated, the preferred ionic compounds are those comprising at least one ionic compound selected from onium cations and metal cations and fluorine organic anions, and organosilicon oligomers containing ionic groups. From the viewpoint that the appearance of the adhesive layer can be improved, the preferred ionic compounds are those comprising at least one ionic compound selected from onium cations and metal cations and fluorine organic anions.

[0121] Ionic compounds can also be ionic liquids. Ionic liquids are molten salts (ionic compounds) that are liquid at 25°C.

[0122] As an organosilicon oligomer containing ionic groups, any suitable organosilicon oligomer containing ionic groups can be used without impairing the effects of the present invention. For example, an organosilicon oligomer containing ionic groups can be listed under the trade name "X-40-2450" manufactured by Shin-Etsu Chemical Co., Ltd.

[0123] As the onium cation, any suitable onium cation can be used without impairing the effects of the present invention. From the viewpoint of further demonstrating the effects of the present invention, such an onium cation is preferably selected from at least one of ammonium cations (nitrogen-containing onium cations), sulfonium cations (sulfur-containing onium cations), and phosphorus-containing onium cations (phosphonium cations), and more preferably ammonium cations.

[0124] As the metal cation, any suitable metal cation can be used without impairing the effects of the present invention. From the perspective of further demonstrating the viewpoint of the present invention, alkali metal cations such as Li cation, Na cation, and K cation are preferred as such metal cations.

[0125] As a fluorinated organic anion, any suitable fluorinated organic anion may be used without impairing the effects of the present invention. The fluorinated organic anion may be fully fluorinated (perfluorinated) or partially fluorinated.

[0126] Examples of such fluorinated organic anions include fluorinated aryl sulfonates, perfluoroalkyl sulfonates, bis(fluorosulfonyl)imides, bis(perfluoroalkyl)sulfonyl)imides, cyanoperfluoroalkyl sulfonamides, bis(cyano)perfluoroalkyl sulfonyl methylates, cyano-bis-(perfluoroalkyl sulfonyl) methylates, tri(perfluoroalkyl sulfonyl) methylates, trifluoroacetates, perfluoroalkylates, tri(perfluoroalkyl sulfonyl) methylates, and (perfluoroalkyl sulfonyl) trifluoroacetamides.

[0127] Among these fluorinated organic anions, from the perspective of further demonstrating the viewpoint of the present invention, perfluoroalkyl sulfonates, bis(fluorosulfonyl)imides, and bis(perfluoroalkyl sulfonyl)imides are preferred, and more specifically, for example, trifluoromethanesulfonates, pentafluoroethanesulfonates, heptafluoropropanesulfonates, nonafluorobutanesulfonates, bis(fluorosulfonyl)imides, and bis(trifluoromethanesulfonyl)imides, with bis(fluorosulfonyl)imides and bis(trifluoromethanesulfonyl)imides being the most preferred.

[0128] From the viewpoint that the effects of the present invention can be further demonstrated, ionic compounds composed of onium cations and fluorine organic anions are more preferred as ionic compounds.

[0129] As a ium cation, it is preferred to have at least one structure selected from the structures shown in general formulas (1) to (4).

[0130]

[0131] In general formula (1), Ra represents a hydrocarbon group with 4 to 20 carbon atoms, optionally containing heteroatoms. Rb and Rc may be the same or different, representing hydrogen or a hydrocarbon group with 1 to 16 carbon atoms, optionally containing heteroatoms. When the nitrogen atom contains a double bond, Rc is not present.

[0132] In general formula (2), Rd represents a hydrocarbon group with 2 to 20 carbon atoms, which may optionally contain heteroatoms. Re, Rf and Rg may be the same or different, representing hydrogen or a hydrocarbon group with 1 to 16 carbon atoms, which may optionally contain heteroatoms.

[0133] In general formula (3), Rh represents a hydrocarbon group with 2 to 20 carbon atoms, which may optionally contain heteroatoms. Ri, Rj and Rk may be the same or different, representing hydrogen or a hydrocarbon group with 1 to 16 carbon atoms, which may optionally contain heteroatoms.

[0134] In general formula (4), Z represents a nitrogen atom, a sulfur atom, or a phosphorus atom. Rl, Rm, Rn, and Ro may be the same or different, representing a hydrocarbon group with 1 to 20 carbon atoms, and optionally containing heteroatoms. In the case where Z is a sulfur atom, Ro is not present.

[0135] Examples of cationic structures represented by general formula (1) include pyridinium cationic structures, pyrrolidine-onium cationic structures, piperidinium cationic structures, cationic structures with a pyrrololine skeleton, and cationic structures with a pyrrole skeleton.

[0136] Specific examples of cations represented by general formula (1) 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, and 1,1-dimethylpyrrolidine cation; 1-ethyl-1-methylpyrrolidine cation, 1-methylpyridinium cation, etc. 1-propylpyrrolidineonium cation, 1-methyl-1-butylpyrrolidineonium cation, 1-methyl-1-pentylpyrrolidineonium cation, 1-methyl-1-hexylpyrrolidineonium cation, 1-methyl-1-heptylpyrrolidineonium cation, 1-ethyl-1-propylpyrrolidineonium cation, 1-ethyl-1-butylpyrrolidineonium cation, 1-ethyl-1-pentylpyrrolidineonium cation, 1-ethyl-1-hexylpyrrolidineonium cation, 1-ethyl-1-heptylpyrrolidineonium cation, 1,1-dipropylpyrrolidineonium cation, 1-propyl-1-butylpyrrolidineonium cation 1,1-Dibutylpyrrolidine-onium cations, etc.; 1-Propylpiperidine-onium cations, 1-pentylpiperidine-onium cations, 1-methyl-1-ethylpiperidine-onium cations, 1-methyl-1-propylpiperidine-onium cations, 1-methyl-1-butylpiperidine-onium cations, 1-methyl-1-pentylpiperidine-onium cations, 1-methyl-1-hexylpiperidine-onium cations, 1-ethyl-1-propylpiperidine-onium cations, 1-ethyl-1-butylpiperidine-onium cations, 1-ethyl-1-pentylpiperidine-onium cations, 1-ethyl-1-hexylpiperidine-onium cations, 1-ethyl-1-propylpiperidine-onium cations, 1-ethyl-1-butylpiperidine-onium cations, 1-ethyl-1-pentylpiperidine-onium cations, 1-ethyl-1-hexylpiperidine-onium cations, 1-ethyl-1-propylpiperidine-onium cations, 1-ethyl-1-butylpiperidine-onium cations, 1-ethyl-1-hexyl ... Piperidinium cations include 1-ethyl-1-heptylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1,1-dibutylpiperidinium cation, etc.; 2-methyl-1-pyrrolline cation; 1-ethyl-2-phenylindole cation; 1,2-dimethylindole cation; 1-ethylcarbazole cation; and these cations further include cations selected from at least one of vinyl (CH2=CH-) and allyl (CH2=CH-CH2-) groups.

[0137] Among these, from the viewpoint of further demonstrating the effects of the present invention, preferred examples include pyridinium cations such as 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, and 1-octyl-4-methylpyridinium cation; 1-ethyl-1-methylpyrrolidine cation, 1-methyl-1-propylpyrrolidine cation, and 1-methyl Pyrrolidine ononium cations include 1-butylpyrrolidine ononium cations, 1-methyl-1-pentylpyrrolidine ononium cations, 1-methyl-1-hexylpyrrolidine ononium cations, 1-methyl-1-heptylpyrrolidine ononium cations, 1-ethyl-1-propylpyrrolidine ononium cations, 1-ethyl-1-butylpyrrolidine ononium cations, 1-ethyl-1-pentylpyrrolidine ononium cations, 1-ethyl-1-hexylpyrrolidine ononium cations, and 1-ethyl-1-heptylpyrrolidine ononium cations; 1-methyl-1-ethylpiperidine ononium cations, and 1-methyl-1-propylpiperidine ononium cations. 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, etc., are piperidinium cations; these cations further have a component selected from vinyl (CH2= The cations are formed from at least one of vinyl (CH-) and allyl (CH2=CH-CH2-) groups, more preferably 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-octyl-4-methylpyridinium cation, 1-methyl-1-propylpyrrolidine cation, 1-methyl-1-propylpiperidinium cation, and these cations further include cations formed from at least one of vinyl (CH2=CH-) and allyl (CH2=CH-CH2-) groups.

[0138] Examples of cationic structures represented by general formula (2) include imidazolium cationic structures, tetrahydropyrimidineonium cationic structures, and dihydropyrimidineonium cationic structures.

[0139] Specific examples of cations represented by general formula (2) 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, and 1-dodecyl-3-methylimidazolium cation. Imidazolium cations include 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, and 1-hexyl-2,3-dimethylimidazolium cation; 1,3-dimethyl-1,4,5,6-tetrahydropyrimidineonium cation, and 1,2,3-trimethyl-1 Tetrahydropyrimidine-onium cations, such as 4,5,6-tetrahydropyrimidine-onium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidine-onium cation, and 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidine-onium cation; 1,3-dimethyl-1,4-dihydropyrimidine-onium cation, 1,3-dimethyl-1,6-dihydropyrimidine-onium cation, and 1,2,3-trimethyl-1,4-dihydropyrimidine-onium cation. Dihydropyrimidine cations such as ononium cations, 1,2,3-trimethyl-1,6-dihydropyrimidine ononium cations, 1,2,3,4-tetramethyl-1,4-dihydropyrimidine ononium cations, and 1,2,3,4-tetramethyl-1,6-dihydropyrimidine ononium cations; these cations further include cations formed from at least one selected from vinyl (CH2=CH-) and allyl (CH2=CH-CH2-) groups.

[0140] From the viewpoint of further demonstrating the effects of the present invention, the preferred cations are 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, and 1-tetradecyl-3- The cations are imidazolium cations, and these cations further include imidazolium cations selected from at least one of vinyl (CH2=CH-) and allyl (CH2=CH-CH2-) cations, more preferably 1-ethyl-3-methylimidazolium cations, 1-hexyl-3-methylimidazolium cations, and these cations further include cations selected from at least one of vinyl (CH2=CH-) and allyl (CH2=CH-CH2-) cations.

[0141] Examples of cationic structures represented by general formula (3) include pyrazolium cationic structures and pyrazolinoline cationic structures.

[0142] Specific examples of cations represented by general formula (3) include, for example, pyrazolium cations such as 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolium cation, 1-ethyl-2,3,5-trimethylpyrazolium cation, 1-propyl-2,3,5-trimethylpyrazolium cation, and 1-butyl-2,3,5-trimethylpyrazolium cation; pyrazolium cations such as 1-ethyl-2,3,5-trimethylpyrazolium cation, 1-propyl-2,3,5-trimethylpyrazolium cation, and 1-butyl-2,3,5-trimethylpyrazolium cation; these cations further include cations formed from at least one of vinyl (CH2=CH-yl) and allyl (CH2=CH-CH2-yl).

[0143] Examples of cationic structures represented by general formula (4) include tetraalkylammonium cationic structures, trialkylsulfonium cationic structures, tetraalkylphosphonium cationic structures, and cationic structures in which a portion of the alkyl group is replaced by an alkenyl group, an alkoxy group, or an epoxy group.

[0144] Specific examples of cations represented by general formula (4) 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, and N,N-dimethyl-N-ethyl-N-hexylammonium cation. Ammonium 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 Cations, 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,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 Tetraalkylammonium cations such as trioctylmethylammonium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation; trialkylsulfonium cations such as trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation; tetraalkylphosphonium cations such as tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation; these cations further include cations formed from at least one selected from vinyl (CH2=CH-yl) and allyl (CH2=CH-CH2-yl).

[0145] As an ionic compound, the preferred options are ionic compounds comprising at least one of the above-mentioned onium cations and metal cations and the above-mentioned fluorine organic anions, organosilicon oligomers containing ionic groups, more preferably ionic compounds comprising at least one of the above-mentioned onium cations and metal cations and the above-mentioned fluorine organic anions, and even more preferably ionic compounds comprising the above-mentioned onium cations and the above-mentioned fluorine organic anions.

[0146] From the viewpoint of further demonstrating the effects of the present invention, as an ionic compound, specifically preferably 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(fluoromethanesulfonyl)imide, 1-octyl-4-methylpyridinium bis(fluorosulfonyl)imide Amine, 1-methyl-1-propylpyrrolidine-onium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpyrrolidine-onium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinonium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpiperidinonium 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 The following are preferred: lithium bis(fluorosulfonyl)imide, 1-allyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide, methyltrioctylammonium bis(trifluoromethanesulfonyl)imide, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, 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, and trimethylpropylammonium bis(trifluoromethanesulfonyl)imide.

[0147] Ionic compounds can be commercially available substances or substances synthesized by any suitable method. For example, ionic liquids can be synthesized by methods such as halide method, hydroxide method, ester method, complexation method, and neutralization method, as described in "Ionic Liquids - The Frontline and Future of Development -" (published by CMC).

[0148] [Fluorine-based additives]

[0149] When fluorine-based additives are added as other components, the easy peelability and antistatic properties of the surface protective film in the embodiments of the present invention can be further improved.

[0150] As a fluorinated additive, any suitable fluorinated additive may be used without impairing the effects of the present invention.

[0151] Fluorine additives can be one type or two or more types.

[0152] The proportion of fluorinated additives relative to the total amount of urethane prepolymer P and polyol A is preferably 0.01% by weight or more, more preferably 0.03% by weight to 30 parts by weight, further preferably 0.05 parts by weight to 10 parts by weight, and particularly preferably 0.05 parts by weight to 1 part by weight. When the proportion of fluorinated additives relative to the total amount of urethane prepolymer P and polyol A is within the above range, the easy peelability and antistatic properties of the surface protective film of the embodiments of the present invention can be further improved.

[0153] From the viewpoint that the effects of the present invention can be further demonstrated, the total amount of fluorinated additives and organosilicon additives (described later) relative to the total amount of urethane prepolymer P and polyol A is 0.01% by weight or more, more preferably 0.03% by weight to 30 parts by weight, further preferably 0.05 parts by weight to 10 parts by weight, and particularly preferably 0.05 parts by weight to 1 part by weight.

[0154] As a fluorinated additive, at least one can be selected from fluorinated compounds, hydroxyl-containing fluorinated compounds, and fluorinated compounds containing cross-linking functional groups.

[0155] Examples of fluorinated compounds include compounds with a fluorinated aliphatic hydrocarbon skeleton, fluorinated organic compounds obtained by copolymerizing organic compounds with fluorinated compounds, and fluorinated compounds containing organic compounds. Examples of fluorinated aliphatic hydrocarbon skeletons include fluorinated C1-C10 alkanes such as fluorinated methane, fluorinated ethane, fluorinated propane, fluorinated isopropane, fluorinated butane, fluorinated isobutane, fluorinated tert-butane, fluorinated pentane, and fluorinated hexane. Here, the designation "C1-C10" refers to a carbon number of 1 to 10.

[0156] As a preferred embodiment of the fluorinated compound, it is an oligomer having a fluorinated group and having hydrophilic and / or lipophilic groups (“specific fluorinated compound”). By employing such a “specific fluorinated compound”, the easy peelability and antistatic properties of the surface protective film of the embodiments of the present invention can be improved. In particular, by using such a “specific fluorinated compound” in combination with an ionic compound, the easy peelability and antistatic properties of the surface protective film of the embodiments of the present invention can be further improved. This is presumably because, due to the specific fluorinated compound, the ionic compound is predominantly present on the surface side (the side that adheres to the adhered object) of the urethane adhesive layer. Representative examples of fluorinated groups include fluorinated alkyl groups (e.g., CF3-, etc.) and / or fluorinated alkylene groups (e.g., -CF2-, CF2-, etc.). A hydrophilic group refers to a group that is hydrophilic, and hydrophilicity is a characteristic commonly known to those skilled in the art as meaning “having an affinity for water” (e.g., see McGraw-Hill Dictionary of Scientific and Technical Terminology (Revised 3rd Edition, Nikkan Kogyo Shimbun), etc.). A lipophilic group is a group that has a lipophilic property. Lipophilicity is a property that is generally known to those skilled in the art as having an affinity for oil (see, for example, McGraw-Hill Dictionary of Scientific and Technical Terminology (3rd Revised Edition, Nikkan Kogyo Shimbun) etc.).

[0157] From the viewpoint that the surface protective film of the embodiment of the present invention can be further improved by using fluorinated compounds, the surface tension when preparing a 0.1% toluene solution is preferably 19.0 mN / m to 26.0 mN / m (the surface tension of toluene is 27.9 mN / m). When the surface tension of the fluorinated compound when preparing a 0.1% toluene solution is in a relatively narrow specific range of 19.0 mN / m to 26.0 mN / m, the surface protective film of the embodiment of the present invention can be further improved.

[0158] From the viewpoint of further improving the antistatic properties of the surface protective film in the embodiments of the present invention, the surface tension of the 0.1% toluene solution prepared by the fluorine-containing compound is preferably 26.0 mN / m to 28.0 mN / m (the surface tension of toluene is 27.9 mN / m). When the surface tension of the fluorine-containing compound prepared by the 0.1% toluene solution is within a relatively narrow specific range of 26.0 mN / m to 28.0 mN / m, the antistatic properties of the surface protective film in the embodiments of the present invention can be further improved.

[0159] As fluorinated compounds, commercially available products include, for example, the substances described below.

[0160] Megafac series manufactured by DIC Co., Ltd.:

[0161] Representative ones are "MegafacF-114", "MegafacF-251", "MegafacF-253", "MegafacF-281", "MegafacF-410", "MegafacF-430", "MegafacF-444", "MegafacF-477", "MegafacF-510", "Megaf acF-551-A", "MegafacF-553", "MegafacF-554", "MegafacF-555-A", "MegafacF-556", "MegafacF-557", "MegafacF-558", "MegafacF-559", "MegafacF-560", "MegafacF-561" , "MegafacF-562", "MegafacF-563", "MegafacF-565", "MegafacF-568", "MegafacF-56 9", "MegafacF-570", "MegafacF-576", "MegafacR-01", "MegafacR-40", "MegafacR-40- LM", "MegafacR-41", "MegafacR-41-LM", "MegafacR-94", "MegafacRS-56", "MegafacRS-72-K", "MegafacRS-75-A", "MegafacRS-75-NS", "MegafacRS-78", "MegafacRS-90", etc.

[0162] Surflon series manufactured by AGC Seimi Chemical Co., Ltd.:

[0163] Representative examples include "S-242", "S-243", and "S-386".

[0164] FC series manufactured by Sumitomo 3M Co., Ltd.

[0165] Representative examples include "FC-4430" and "FC-4432".

[0166] Ftergent series manufactured by NEOS Co., Ltd.:

[0167] Representative examples include “Ftergent100”, “Ftergent100C”, “Ftergent110”, “Ftergent150”, “Ftergent150CH”, “Ftergent250”, and “Ftergent400SW”.

[0168] PF series manufactured by Kitamura Chemical Industry Co., Ltd.:

[0169] Representative examples include “PF-136A”, “PF-156A”, “PF-151N”, “PF-636”, “PF-6320”, “PF-656”, “PF-6520”, “PF-651”, “PF-652”, and “PF-3320”.

[0170] As hydroxyl-containing fluorinated compounds, conventionally known resins can be used, such as hydroxyl-containing fluoropolymers described in International Publication No. 94 / 06870, Japanese Patent Application Publication No. 8-12921, Japanese Patent Application Publication No. 10-72569, Japanese Patent Application Publication No. 4-275379, International Publication No. 97 / 11130, and International Publication No. 96 / 26254. Other hydroxyl-containing fluoropolymers include fluoroolefin copolymers described in Japanese Patent Application Publication No. 8-231919, Japanese Patent Application Publication No. 10-265731, Japanese Patent Application Publication No. 10-204374, and Japanese Patent Application Publication No. 8-12922. Furthermore, examples include copolymers of compounds containing fluorinated alkyl groups within hydroxyl-containing compounds, fluorinated organic compounds obtained by copolymerizing hydroxyl-containing compounds with fluorinated compounds, and fluorinated compounds containing hydroxyl-containing organic compounds. Commercially available examples of such hydroxyl-containing fluorinated compounds include those marketed under the trade names "Lumiflon" (manufactured by Asahi Glass Co., Ltd.), "Cefral Coat" (manufactured by Chuo Glass Co., Ltd.), "Zaflon" (manufactured by Toa Synthetic Co., Ltd.), and "Zeffle" (manufactured by Daikin Industries, Ltd.).

[0171] Examples of fluorinated compounds containing crosslinking functional groups include carboxylic acid compounds with fluorinated alkyl groups, such as perfluorooctanoic acid; copolymers of compounds containing fluorinated alkyl groups; fluorinated organic compounds obtained by copolymerizing compounds with crosslinking functional groups and fluorinated compounds; and fluorinated compounds containing compounds with crosslinking functional groups. Commercially available examples of such fluorinated compounds with crosslinking functional groups include those with trade names 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," and "Megafac RS-90" (manufactured by DIC Corporation).

[0172] Among fluorinated compounds that can be obtained as commercially available products, representative examples of substances belonging to the aforementioned "oligomers having fluorinated groups and having hydrophilic and / or lipophilic groups" include those manufactured by DIC Corporation:

[0173] "MegafacF-477" (an oligomer containing fluorinated, hydrophilic, and lipophilic groups; surface tension of 26.4 mN / m when prepared as a 0.1% toluene solution)

[0174] "MegafacF-551-A" (an oligomer containing fluorinated and lipophilic groups, with a surface tension of 25.6 mN / m when prepared as a 0.1% toluene solution).

[0175] "MegafacF-553" (an oligomer containing fluorinated, hydrophilic, and lipophilic groups; surface tension of 26.4 mN / m when prepared as a 0.1% toluene solution)

[0176] "MegafacF-554" (an oligomer containing fluorinated and lipophilic groups, with a surface tension of 25.0 mN / m when prepared as a 0.1% toluene solution).

[0177] "MegafacF-555-A" (an oligomer containing fluorinated, hydrophilic, and lipophilic groups; surface tension of 20.4 mN / m when prepared as a 0.1% toluene solution).

[0178] "MegafacF-557" (an oligomer containing fluorinated, hydrophilic, and lipophilic groups; surface tension of 26.3 mN / m when prepared as a 0.1% toluene solution)

[0179] "MegafacF-559" (an oligomer containing fluorinated, hydrophilic, and lipophilic groups; surface tension of 26.1 mN / m when prepared as a 0.1% toluene solution)

[0180] "MegafacF-563" (an oligomer containing fluorinated and lipophilic groups, with a surface tension of 20.2 mN / m when prepared as a 0.1% toluene solution).

[0181] "MegafacF-569" (an oligomer containing fluorine-containing and hydrophilic groups, with a surface tension of 19.7 mN / m when prepared as a 0.1% toluene solution), etc.

[0182] [Organosilicon-based additives]

[0183] When organosilicon additives are included as other components, the easy peelability of the surface protective film in embodiments of the present invention can be further improved.

[0184] As an organosilicon additive, any suitable organosilicon additive may be used without impairing the effects of the present invention.

[0185] Organosilicon additives can be one type or two or more types.

[0186] The proportion of the silicone additive relative to the total amount of urethane prepolymer P and polyol A is preferably 0.01% by weight or more, more preferably 0.015% by weight to 30 parts by weight, further preferably 0.02 parts by weight to 10 parts by weight, and particularly preferably 0.025 parts by weight to 1 part by weight. When the proportion of the silicone additive relative to the total amount of urethane prepolymer P and polyol A is within the above range, the easy peelability of the surface protective film of the embodiment of the present invention can be further improved.

[0187] From the viewpoint that the effects of the present invention can be further demonstrated, the total amount of the aforementioned fluorinated additives and organosilicon additives relative to the total amount of urethane prepolymer P and polyol A is 0.01% by weight or more, more preferably 0.03% by weight to 30 parts by weight, further preferably 0.05 parts by weight to 10 parts by weight, and particularly preferably 0.05 parts by weight to 1 part by weight.

[0188] Regarding organosilicon additives, any suitable organosilicon additive may be used without impairing the effects of the present invention. Examples of such organosilicon additives include reactive organosilicon oils and non-reactive organosilicon oils.

[0189] Examples of reactive silicone oils include: side-chain reactive silicone oils in which organic groups are bonded as side chains to Si atoms that provide siloxane bonds; two-terminal reactive silicone oils in which organic groups are bonded to Si atoms at both ends of the structure; single-terminal reactive silicone oils in which organic groups are bonded to only one of the two Si atoms at the ends of the structure; and two-terminal reactive silicone oils in which organic groups are bonded as side chains to Si atoms that provide siloxane bonds and organic groups are bonded to Si atoms at both ends of the structure.

[0190] Examples of side-chain reactive silicone oils include: amino-modified, epoxy-modified, carbinol-modified, mercapto-modified, carboxyl-modified, and methylhydrosilicone-type side-chain reactive silicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0191] Examples of two-terminal reactive silicone oils include, for example, amino-modified two-terminal reactive silicone oils, epoxy-modified two-terminal reactive silicone oils, methanol-modified two-terminal reactive silicone oils, methacrylic acid-modified two-terminal reactive silicone oils, polyether-modified two-terminal reactive silicone oils, mercapto-modified two-terminal reactive silicone oils, carboxyl-modified two-terminal reactive silicone oils, phenol-modified two-terminal reactive silicone oils, silanol-terminal two-terminal reactive silicone oils, acrylic acid-modified two-terminal reactive silicone oils, and carboxylic anhydride-modified two-terminal reactive silicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. Two-terminal reactive organosilicon oils modified with methanol, such as “KF-6000”, “KF-6001”, “KF-6002”, “KF-6003”, and “KF-6028”, can be particularly preferred.

[0192] Examples of single-terminal reactive silicone oils include: single-terminal reactive modified silicone oils and single-terminal reactive silicone oils with average single-terminal carboxyl group modification. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. Methanol-modified single-terminal reactive silicone oils such as "X-22-170BX", "X-22-170DX", and "X-22-4015" manufactured by Shin-Etsu Chemical Co., Ltd. are particularly preferred.

[0193] Examples of reactive silicone oils with two-terminal side chains include: reactive silicone oils modified with amino-terminal methoxy groups on the side chains, and reactive silicone oils with epoxy-modified side chains. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0194] Examples of non-reactive silicone oils include: side-chain type non-reactive silicone oils in which organic groups are bonded as side chains to the Si atoms that provide siloxane bonds, and two-terminal type non-reactive silicone oils in which organic groups are bonded to the Si atoms located at both ends of the structure.

[0195] Examples of side-chain non-reactive silicone oils include: polyether-modified side-chain non-reactive silicone oils, aralkyl-modified side-chain non-reactive silicone oils, fluoroalkyl-modified side-chain non-reactive silicone oils, long-chain alkyl-modified side-chain non-reactive silicone oils, higher fatty acid ester-modified side-chain non-reactive silicone oils, side-chain non-reactive silicone oils containing higher fatty acids, and phenyl-modified side-chain non-reactive silicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. The following polyether-modified side-chain non-reactive silicone oils manufactured by Shin-Etsu Chemical Industry Co., Ltd. are particularly preferred: “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”, and “X-22-4515”.

[0196] Among these polyether-modified side-chain non-reactive silicone oils, from the viewpoint of further reducing residue, polyether-modified side-chain non-reactive silicone oils with an HLB value of 8 or higher are preferred, more preferably 9 or higher, and even more preferably 10 or higher. Examples of such polyether-modified 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).

[0197] Examples of two-terminated non-reactive silicone oils include, for example, polyether-modified two-terminated non-reactive silicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. Polyether-modified two-terminated non-reactive silicone oils, such as "KF-6004" manufactured by Shin-Etsu Chemical Co., Ltd., are particularly preferred.

[0198] In addition to the above, any suitable organosilicon additives known in the past may be used as organosilicon additives. Examples of such organosilicon additives include: siloxane-bonded polymers other than those described above, hydroxyl-containing organosilicon compounds other than those described above, and crosslinking-functional organosilicon compounds other than those described above.

[0199] Commercially available products containing siloxane bonds, other than those mentioned above, include, for example, products under the trade name "LE-302" (manufactured by Kyoesha Chemical Co., Ltd.), and BYK-Chemie Japan's BYK series leveling agents ("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", " ...33", "BYK-333", "BYK-337", "BYK-341", "BYK-332", "BYK-333", "BYK-333", "BYK-333", "BYK-337", "BYK-341", "BYK-332", "BYK-333", "BYK-333", "BYK-333", "BYK-333", "BYK-333", "BY K-344", "BYK-345 / 346", "BYK-347", "BYK-348", "BYK-349", "BYK-370", "BYK-375", "BYK-377", "BYK-378", "B YK-UV3500", "BYK-UV3510", "BYK-UV3570", "BYK-3550", "BYK-SILCLEAN3700", "BYK-SILCLEAN3720", etc.), Algin Chemie's AC series leveling agents ("AC FS180", "AC FS360", "AC S20", etc.), Kyoei Chemical Co., Ltd.'s POLYFLOW series leveling agents ("POLYFLOW KL-400X", "POLYFLOW KL-400HF", "POLYFLOW KL-401", "POLYFLOW KL-402", "POLYFLOW KL-403", "POLYFLOW KL-404", etc.), Shin-Etsu Chemical Co., Ltd.'s KP series leveling agents ("KP-323", "KP-326", "KP-341", "KP-104", "KP-110", "KP-112", etc.), Toray Dow Corning Co., Ltd. produces leveling agents ("LP-7001", "LP-7002", "8032ADDITIVE", "57ADDITIVE", "L-7604", "FZ-2110", "FZ-2105", "67ADDITIVE", "8618ADDITIVE", "3ADDITIVE", "56ADDITIVE", etc.).

[0200] Other commercially available products containing hydroxyl-containing organosilicones besides those mentioned above include, for example, "BYK-370", "BYK-SILCLEAN3700", and "BYK-SILCLEAN3720" manufactured by BYK-Chemie Japan.

[0201] Commercially available organosilicon compounds containing cross-linking functional groups, other than those mentioned above, include, for example, “BY16-855”, “SF8413”, “BY16-839”, “SF8421”, “BY16-750”, “BY16-880”, and “BY16-152C” manufactured by Toray Dow Corning Co., Ltd.

[0202] [Antioxidants]

[0203] The urethane-based adhesive composition, from the perspective of inhibiting the deterioration of the urethane-based adhesive layer, optionally includes antioxidants as other components. There may be only one type of antioxidant or two or more types.

[0204] The antioxidant content in the urethane-based adhesive composition can be any suitable proportion without impairing the effects of the present invention. Such a proportion, calculated relative to the total amount of the urethane prepolymer P and polyol A, is preferably 0.01% to 10% by weight or more, more preferably 0.05% to 5% by weight, further preferably 0.1% to 3% by weight, and particularly preferably 0.2% to 1% by weight.

[0205] Examples of antioxidants include free radical chain inhibitors and peroxide decomposers.

[0206] Examples of free radical chain inhibitors include phenolic antioxidants and amine antioxidants.

[0207] Examples of peroxide decomposing agents include sulfur-based antioxidants and phosphorus-based antioxidants.

[0208] Examples of phenolic antioxidants include monophenolic antioxidants, bisphenolic antioxidants, and high molecular weight phenolic antioxidants.

[0209] Examples of monophenolic antioxidants include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, and stearate β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0210] Examples of bisphenol-based antioxidants include 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), and 3,9-bis[1,1-dimethyl-2-[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane.

[0211] Examples of high molecular weight phenolic antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-tert-butylphenyl)butyrate]diol ester, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0212] Examples of sulfur-based antioxidants include dilaurate 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearate 3,3'-thiodipropionate.

[0213] Examples of phosphorus-based antioxidants include triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite.

[0214] [Ultraviolet absorber]

[0215] The urethane-based adhesive composition, from the perspective of inhibiting the deterioration of the urethane-based adhesive layer, optionally includes an ultraviolet absorber as another component. The ultraviolet absorber may be only one type or may be two or more types.

[0216] The proportion of the ultraviolet absorber in the urethane-based adhesive composition can be any suitable proportion without impairing the effects of the present invention. Such a proportion, based on the proportion of the ultraviolet absorber relative to the total amount of urethane prepolymer P and polyol A, is preferably 0.01% to 10% by weight or more, more preferably 0.05% to 5% by weight, further preferably 0.1% to 3% by weight, and particularly preferably 0.2% to 1% by weight.

[0217] Examples of UV absorbers include benzophenone-based UV absorbers, benzotriazole-based UV absorbers, salicylic acid-based UV absorbers, oxaloylaniline-based UV absorbers, cyanoacrylate-based UV absorbers, and triazine-based UV absorbers.

[0218] Examples of benzophenone-based ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 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.

[0219] 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',5'-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole. ,5'-di-tert-pentylphenyl)benzotriazole, 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, 2-[2'-hydroxy-3'-(3”,4”,5”,6”,-tetrahydrophthalimidemethyl)-5'-methylphenyl]benzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2-yl)phenol], 2-(2'-hydroxy-5'-methacryloyloxyphenyl)-2H-benzotriazole.

[0220] Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, p-tert-butyl phenyl salicylate, and p-octyl phenyl salicylate.

[0221] Examples of cyanoacrylate-based ultraviolet absorbers include 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate and ethyl-2-cyano-3,3'-diphenyl acrylate.

[0222] [Light stabilizer]

[0223] The urethane-based adhesive composition, from the perspective of inhibiting the deterioration of the urethane-based adhesive layer, optionally includes a light stabilizer as another component. The light stabilizer may be one type or two or more types.

[0224] The proportion of the light stabilizer in the urethane-based adhesive composition can be any suitable proportion without impairing the effects of the present invention. Such a proportion, based on the proportion of the light stabilizer relative to the total amount of urethane prepolymer P and polyol A, is preferably 0.01% to 10% by weight or more, more preferably 0.05% to 5% by weight, further preferably 0.1% to 3% by weight, and particularly preferably 0.2% to 1% by weight.

[0225] Examples of light stabilizers include hindered amine light stabilizers and ultraviolet stabilizers.

[0226] Examples of hindered amine light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, and methyl-1,2,2,6,6-pentamethyl-4-piperidinyl sebacate.

[0227] Examples of UV stabilizers include bis(octylphenyl)sulfide, [2,2'-thiobis(4-tert-octylphenol)]-n-butylamine nickel, nickel complex-3,5-di-tert-butyl-4-hydroxybenzyl-phosphate monoethyl ester, nickel dibutyldithiocarbamate, benzoate-type quenchers, and nickel dibutyldithiocarbamate.

[0228] [Fatty acid esters]

[0229] The urethane-based adhesive composition may optionally include fatty acid esters as other components to improve the wettability of the urethane-based adhesive layer. There may be only one type of fatty acid ester or two or more types.

[0230] The number-average molecular weight (Mn) of the fatty acid ester is preferably 200–400, more preferably 210–395, further preferably 230–380, particularly preferably 240–360, and most preferably 250–350. By adjusting the number-average molecular weight (Mn) of the fatty acid ester to the above range, the wetting speed can be further improved. If the number-average molecular weight (Mn) of the fatty acid ester is too small, there is a concern that even with a large addition amount, the wetting speed will not increase. If the number-average molecular weight (Mn) of the fatty acid ester is too large, there is a concern that the curing properties of the adhesive during drying will deteriorate, adversely affecting not only wetting properties but also other adhesive properties.

[0231] As fatty acid esters, any suitable fatty acid ester may be used without impairing the effects of the present invention. Examples of such fatty acid esters include, for instance, polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, glyceryl behenate monoester, cetyl 2-ethylhexanoate, isopropyl myristate, isopropyl palmitate, cholesterol isostearate, lauryl methacrylate, coconut oil fatty acid methyl ester, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyl dodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearate, isotridecyl stearate, triglyceride 2-ethylhexanoate, butyl laurate, octyl oleate, etc.

[0232] <<1-2. Substrate Layer>>

[0233] The thickness of the substrate layer can be any appropriate thickness depending on the application. The thickness of the substrate layer is preferably 5 μm to 300 μm, more preferably 10 μm to 250 μm, even more preferably 15 μm to 200 μm, and particularly preferably 20 μm to 150 μm.

[0234] The substrate layer can be a single layer or a laminate of two or more layers. The substrate layer can also be extended.

[0235] The substrate layer can be made of any suitable material depending on the application. Examples include plastics, paper, metal films, and non-woven fabrics. Plastics are preferred. The substrate layer can be composed of one material or two or more materials. For example, it can be composed of two or more plastics.

[0236] Examples of the aforementioned plastics include polyester resins, polyamide resins, and polyolefin resins. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include homopolymers of olefin monomers and copolymers of olefin monomers. Specific examples of polyolefin resins include: homopolymer polypropylene; propylene copolymers such as block copolymers, random copolymers, and graft copolymers in which ethylene is a copolymer component; Reactor TPO; ethylene-based polymers such as low-density, high-density, linear low-density, and ultra-low-density polymers; and ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-methacrylic acid copolymers, and ethylene-methyl methacrylate copolymers.

[0237] The substrate layer may contain any suitable additives as needed. Examples of additives that may be included in the substrate layer include antioxidants, UV absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, number, and content of additives in the substrate layer can be appropriately determined according to the purpose. Especially when the substrate layer material is plastic, it is preferable to contain several of the above-mentioned additives for the purpose of preventing deterioration. From the viewpoint of improving weather resistance, antioxidants, UV absorbers, light stabilizers, and fillers are particularly preferred as additives.

[0238] Any suitable antioxidant can be used. Examples of such antioxidants include phenolic antioxidants, phosphorus-based processing heat stabilizers, lactone-based processing heat stabilizers, sulfur-based heat stabilizers, and phenol-phosphorus antioxidants. Regarding the proportion of the antioxidant, it is preferably 1% by weight or less, more preferably 0.5% by weight or less, and even more preferably 0.01% by weight to 0.2% by weight, relative to the base resin of the substrate layer (when the substrate layer is a blend, the blend is the base resin).

[0239] Any suitable ultraviolet absorber can be used as the ultraviolet absorber. Examples of such ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and benzophenone-based ultraviolet absorbers. Regarding the content ratio of the ultraviolet absorber, it 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, relative to the base resin forming the substrate layer (when the substrate layer is a blend, the blend is the base resin).

[0240] Any suitable light stabilizer can be used. Examples of such light stabilizers include hindered amine light stabilizers and benzoate light stabilizers. Regarding the content ratio of the light stabilizer, it 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, relative to the base resin forming the substrate layer (when the substrate layer is a blend, the blend is the base resin).

[0241] Any suitable filler can be used. Examples of such fillers include inorganic fillers. Specifically, examples of inorganic fillers include carbon black, titanium oxide, and zinc oxide. Regarding the filler content ratio, it 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, relative to the base resin forming the substrate layer (when the substrate layer is a blend, the blend is the base resin).

[0242] Furthermore, as additives, for the purpose of imparting antistatic properties, inorganic antistatic agents such as surfactants, inorganic salts, polyols, metal compounds, and carbon, as well as inorganic, low molecular weight, and high molecular weight antistatic agents, are preferred. In particular, from the viewpoint of preventing contamination and maintaining adhesion, high molecular weight antistatic agents and carbon are preferred.

[0243] <<<<2. Manufacturing method of surface protective film>>>>

[0244] The surface protective film of the present invention can be manufactured by any suitable method. For example, it can be manufactured by any suitable method such as the following:

[0245] (1) A method for applying a solution or hot melt liquid of an adhesive layer forming material onto a substrate layer.

[0246] (2) A method for transferring an adhesive layer coated and formed on a release liner to a substrate layer.

[0247] (3) A method for extruding the adhesive layer forming material and forming it onto the substrate layer.

[0248] (4) A method of extruding a substrate layer and an adhesive layer in two or more layers;

[0249] (5) A method of laminating an adhesive layer onto a substrate layer as a single layer or a method of laminating an adhesive layer and a laminate together as two layers.

[0250] (6) A method of laminating two or more layers of adhesive layer with substrate layer such as film or laminate layer.

[0251] Coating methods include, for example, roller coating, comma coating, die coating, reverse coating, screen printing, and gravure coating.

[0252] <<<<3. Applications of Surface Protective Films>>>>

[0253] The surface protective film of the embodiments of the present invention can be used for any suitable application. Preferably, the surface protective film of the present invention causes very little contamination to the adhered object, preferably exhibits excellent wettability and reprocessability, and is therefore preferably used for surface protection of, for example, optical components and electronic components. Examples of optical components include touch panels using LCDs, color filters used in LCDs, polarizing plates, etc.

[0254] Components, such as optical components and electronic components, to which the surface protective film of the present invention is attached can be repeatedly attached and peeled off by manual operation.

[0255] That is, the optical component of the embodiments of the present invention is bonded with the surface protective film of the present invention. Additionally, the electronic component of the embodiments of the present invention is bonded with the surface protective film of the present invention.

[0256] Example

[0257] The present invention will now be specifically described through examples, but the present invention is not limited to these examples in any way. It should be noted that the testing and evaluation methods in the examples are as follows. It should also be noted that when "parts" are used, unless otherwise stated, they refer to "parts by weight," and when "%" are used, unless otherwise stated, they refer to "% by weight."

[0258] <Adhesion to glass>

[0259] The protective film (25mm wide x 140mm long) from which the separator was removed was adhered to the glass (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) by passing it once under a 2kg hand roller. It was then placed at an ambient temperature of 23°C for 30 minutes. The resulting evaluation specimen was tested using a tensile testing machine. The tensile testing machine used was the "Autograph AG-Xplus HS 6000mm / min high-speed model (AG-50NX plus)" manufactured by Shimadzu Corporation. After setting the evaluation specimen on the tensile testing machine, the tensile test was started. The tensile test conditions were set as peel angle = 180 degrees and peel speed (tensile speed) = 300mm / min. The load at which the protective film was peeled from the glass was measured, and the average load at this point was taken as the adhesive force (peel force) of the protective film to the glass.

[0260] <Regular adhesion rate of glass>

[0261] A protective film was applied to the entire surface of a glass plate (Matsunami Glass, 1.35mm x 10cm x 10cm) using a hand roller. After 24 hours of storage at 23°C and 55% RH, the protective film was peeled off at a peel angle of 180 degrees and a speed of 0.3m / min. A 19mm wide strip of No. 31B tape (manufactured by Nitto Denko Corporation, substrate thickness: 25μm) was then applied by passing it once through a 2.0kg roller at 23°C and 55% RH. After curing for 30 minutes at 23°C and 55% RH, the adhesive strength was measured using a tensile testing machine (Shimadzu Corporation, trade name "Autograph AG-Xplus HS 6000mm / min high-speed model (AG-50NX plus)") at a peel angle of 180 degrees and a tensile speed of 300mm / min.

[0262] In addition, the adhesive force of 19mm wide No.31B tape was measured on glass plates that had not undergone the above treatment, and the residual adhesion rate was calculated using the following formula.

[0263] Residual adhesion rate (%) = (Adhesion of No. 31B to the glass plate after peeling off the surface protective film / Adhesion of No. 31B to the glass plate) × 100

[0264] The residual adhesion rate is an indicator of the extent to which the adhesive component of the surface protective film transfers and contaminates the surface relative to the adhered object. In other words, a higher residual adhesion rate indicates a better surface protective film that is less contaminated to the adhered object, while a lower residual adhesion rate indicates that the surface of the adhered object is more contaminated by the adhesive component and other substances.

[0265] <Glass peel electrostatic voltage resistance>

[0266] The protective film, after being peeled off from the separator, was cut into pieces 70 mm wide and 100 mm long. It was then pressed onto the surface of glass (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) using a hand roller, with one end of the protective film extending 30 mm from the end of the substrate. The sample was placed at 23°C and 50% RH for one day, and then positioned at a predetermined location on a sample holder 20 mm high. The end of the protective film extending 30 mm from the substrate was fixed to an automatic winding machine (not shown), and peeled off at a peel angle of 150° and a peel speed of 30 m / min. The resulting surface potential was measured using a potentiometer (manufactured by SHISHIDOELECTROSTATIC, LTD., model "STATIRON DZ-4") fixed 30 mm above the center of the substrate, measuring the "peel electrostatic voltage". The measurement was performed at 23°C and 50% RH.

[0267] <Haze>

[0268] A urethane-based adhesive composition was coated onto the release-treated surface of a 75 μm thick polyester film (trade name: Diafol MRF75, manufactured by Mitsubishi Chemical Corporation) that had undergone silicone release treatment on one side, under the conditions of the Examples and Comparative Examples, and dried to form a urethane-based adhesive layer. Next, a 75 μm thick polyester film (trade name: Diafol MRE75, manufactured by Mitsubishi Chemical Corporation) that had undergone silicone release treatment on one side was coated onto the surface of the urethane-based adhesive layer, with the release-treated surface of the polyester film becoming the urethane-based adhesive layer side, and the mixture was cured at room temperature for 5 days.

[0269] Prepare two sheets of paper with a 20mm x 20mm hole in the center of each 50mm x 50mm thick sheet. Press the sample onto one sheet of paper by pressing the roller once, and then press the other sheet of paper onto the sample.

[0270] The haze of the evaluation sample obtained by the above operation was measured using the "HM-150N" manufactured by Murakami Color Technology Research Institute Co., Ltd.

[0271] Can the adhesive be applied in a thick coat?

[0272] For each embodiment and comparative example, a urethane-based adhesive solution was applied to a substrate formed of polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) and dried, and it was observed whether an adhesive layer with a thickness of 75 μm was obtained after drying.

[0273] 〇: It can form an adhesive layer with a thickness of 75μm after drying.

[0274] ×: Cannot form an adhesive layer with a thickness of 75μm after drying.

[0275] [Manufacturing Example 1]: Manufacturing of carbamate prepolymers

[0276] In a polymerization experimental apparatus equipped with a 1L round-bottom detachable flask, a detachable cap, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and stirring blades, 150g of polypropylene glycol (product name "Sannix PP-2000", manufactured by Sanyo Chemical Industry Co., Ltd.), 150g of polyester polyol (product name "kuraraypolyol P-2010", manufactured by Kuraray Co., Ltd.), 110g of toluene (manufactured by Tosoh Co., Ltd.) as solvent, and 0.041g of dibutyltin dilaurate (IV) (manufactured by Wako Pure Chemical Industries Co., Ltd.) as catalyst were added, and nitrogen replacement was carried out at room temperature for 1 hour while stirring. Subsequently, 33.5 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added under nitrogen flow and stirring. The solution temperature was controlled and maintained at 90±2℃ in a water bath for 4 hours. Then, 74.9 g of polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Co., Ltd.) was added. The solution temperature was controlled and maintained at 90±2℃ in a water bath for 2 hours. Finally, 25.4 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added. The solution temperature was controlled and maintained at 90±2℃ in a water bath for 2 hours, yielding a solution of urethane prepolymer. It should be noted that during polymerization, toluene was added dropwise to control the temperature and prevent decreased stirability due to increased viscosity. The total amount of toluene added was 320 g. The solids concentration of the urethane prepolymer solution was 50% by weight. The urethane prepolymer was used in the examples and comparative examples.

[0277] [Example 1]

[0278] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP4000 (manufactured by Sanyo Chemical Co., Ltd., Mn=4000), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured and dried at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (1). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (1). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 1.

[0279] [Example 2]

[0280] A urethane-based adhesive solution was obtained by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.1 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (2). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (2). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0281] [Example 3]

[0282] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 5 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Co., Ltd., Mn=1000), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured and dried at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (3). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (3). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0283] [Example 4]

[0284] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP600 (manufactured by Sanyo Chemical Co., Ltd., Mn=600), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured and dried at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (4). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (4). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0285] [Example 5]

[0286] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP400 (manufactured by Sanyo Chemical Co., Ltd., Mn=400), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (5). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (5). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0287] [Example 6]

[0288] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 35 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 9.1 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (6). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (6). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 1.

[0289] [Example 7]

[0290] A urethane-based adhesive solution was obtained by diluting 60 parts by weight of a urethane prepolymer, 25 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 8.5 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Co., Ltd.), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (7). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (7). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0291] [Example 8]

[0292] A urethane-based adhesive solution was prepared by diluting 60 parts by weight of a urethane prepolymer, 28 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 12 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 7.8 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Co., Ltd.), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (8). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (8). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0293] [Example 9]

[0294] A urethane-based adhesive solution was obtained by diluting 80 parts by weight of a urethane prepolymer, 12 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 8 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 5.8 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (9). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (9). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0295] [Example 10]

[0296] A urethane-based adhesive solution was prepared by diluting 80 parts by weight of a urethane prepolymer, 15 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 5 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 5.2 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm, and cured at a drying temperature of 130°C for 3 minutes to form an adhesive layer of adhesive composition (10). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (10). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 1.

[0297] [Example 11]

[0298] A urethane-based adhesive solution was prepared by diluting 95 parts by weight of a urethane prepolymer, 3 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured and dried at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (11). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (11). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0299] [Example 12]

[0300] A urethane-based adhesive solution was obtained by diluting 95 parts by weight of a urethane prepolymer, 3.5 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 1.5 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 3.5 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), an antioxidant (Irganox 1010, manufactured by BASF), and a catalyst (iron acetylacetone, manufactured by Nippon Chemical Industry Co., Ltd.) with ethyl acetate in a manner where the total solid content was 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer of the adhesive composition (12). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (12). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 1.

[0301] [Example 13]

[0302] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3015 (manufactured by Asahi Glass Co., Ltd., Mn=15000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 9.2 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Co., Ltd.), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (13). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (13). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0303] [Example 14]

[0304] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3008 (manufactured by Asahi Glass Co., Ltd., Mn=8000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.8 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (14). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (14). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 1.

[0305] [Example 15]

[0306] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3006 (manufactured by Asahi Glass Co., Ltd., Mn=5000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 12.7 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (15). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (15). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 1.

[0307] [Example 16]

[0308] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.05 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical 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 iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate formed of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (16). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (16). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0309] [Example 17]

[0310] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.1 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical 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 iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate formed of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (17). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (17). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0311] [Example 18]

[0312] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical 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 iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate formed of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (18). Next, a 25 μm thick release sheet (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) made of polyester resin with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (18). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0313] [Example 19]

[0314] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 1.0 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical 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 iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (19). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (19). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0315] [Example 20]

[0316] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 5 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Co., Ltd., Mn=1000), and an isocyanate compound (Coronate) as a crosslinking agent. 12.9 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical 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 iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate formed of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (20). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (20). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0317] [Example 21]

[0318] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP600 (manufactured by Sanyo Chemical Co., Ltd., Mn=600), and an isocyanate compound (Coronate) as a crosslinking agent. 12.7 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical 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 iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate formed of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (21). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (21). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0319] [Example 22]

[0320] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 18 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 2 parts by weight of Sannix GP400 (manufactured by Sanyo Chemical Co., Ltd., Mn=400), and an isocyanate compound (Coronate) as a crosslinking agent. 13.8 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an antioxidant and an ionic compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate formed of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (22). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (22). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0321] [Example 23]

[0322] The mixture comprises 80 parts by weight of a urethane prepolymer, 15 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 5 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 5.2 parts by weight of HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical 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 iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate formed of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (23). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (23). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 2.

[0323] [Example 24]

[0324] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.05 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.1 parts by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (24). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (24). The film was cured at room temperature for 5 days for evaluation. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0325] [Example 25]

[0326] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.1 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.1 parts by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (25). Next, a 25 μm thick release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (25). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0327] [Example 26]

[0328] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.1 parts by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (26). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (26). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0329] [Example 27]

[0330] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 1.0 part by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.1 parts by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (27). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (27). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0331] [Example 28]

[0332] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.05 parts by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (28). Next, a 25 μm thick release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (28). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0333] [Example 29]

[0334] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.5 parts by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a polyester resin substrate (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (29). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (29). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0335] [Example 30]

[0336] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 1.0 part by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (30). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (30). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0337] [Example 31]

[0338] The mixture comprises 50 parts by weight of urethane prepolymer, 35 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 15 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 9.1 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.1 parts by weight of F-477 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (31). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (31). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0339] [Example 32]

[0340] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.05 parts by weight of F-563 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (32). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (32). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0341] [Example 33]

[0342] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.1 parts by weight of F-563 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (33). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (33). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0343] [Example 34]

[0344] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.5 parts by weight of F-563 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (34). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (34). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0345] [Example 35]

[0346] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 1.0 part by weight of F-563 (manufactured by DIC Corporation), 0.5 part by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 part by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (35). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (35). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0347] [Example 36]

[0348] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.5 parts by weight of F-569 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75μm, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (36). Next, a 25 μm thick release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (36). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0349] [Example 37]

[0350] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.5 parts by weight of F-552 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (37). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (37). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0351] [Example 38]

[0352] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.5 parts by weight of F-559 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (38). Next, a 25 μm thick release sheet (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) made of polyester resin with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (38). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0353] [Example 39]

[0354] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. 0.5 parts by weight of F-556 (manufactured by DIC Corporation), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, the urethane-based adhesive solution was coated onto a substrate made of polyester resin (trade name "T100-75S", thickness 75μm, manufactured by Mitsubishi Chemical Corporation) with a thickness of 75μm after drying, and cured and dried at a drying temperature of 130°C and a drying time of 3 minutes to form an adhesive layer formed by the adhesive composition (39). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (39). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 3.

[0355] [Example 40]

[0356] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.) 10.2 parts by weight, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound 0.5 parts by weight, hydroxyl-containing reactive silicone oil X-22-4015 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 parts by weight, Irganox1010 (manufactured by BASF) as an antioxidant 0.5 parts by weight, and ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst 0.03 parts by weight were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (40). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (40). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0357] [Example 41]

[0358] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX:C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl-containing reactive silicone oil KF6001 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with an overall solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (41). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (41). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 4.

[0359] [Example 42]

[0360] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX:C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl-containing reactive silicone oil KF6002 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with an overall solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (42). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (42). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 4.

[0361] [Example 43]

[0362] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX:C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl-containing reactive silicone oil KF6028 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (43). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (43). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before the evaluation. The results are shown in Table 4.

[0363] [Example 44]

[0364] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX:C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl-free non-reactive silicone oil KF643 (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with an overall solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (44). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (44). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0365] [Example 45]

[0366] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.) 10.2 parts by weight, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound 0.5 parts by weight, KF640 non-reactive silicone oil without hydroxyl groups (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 parts by weight, Irganox1010 (manufactured by BASF) as an antioxidant 0.5 parts by weight, and ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst 0.03 parts by weight were diluted with ethyl acetate to obtain a urethane-based adhesive solution with an overall solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured and dried at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (45). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (45). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0367] [Example 46]

[0368] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX:C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound, 0.1 parts by weight of hydroxyl-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured and dried at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (46). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (46). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0369] [Example 47]

[0370] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.) 10.2 parts by weight, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound 0.5 parts by weight, KF352A non-reactive silicone oil without hydroxyl groups (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 parts by weight, Irganox1010 (manufactured by BASF) as an antioxidant 0.5 parts by weight, and ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst 0.03 parts by weight were diluted with ethyl acetate to obtain a urethane-based adhesive solution with an overall solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (47). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (47). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0371] [Example 48]

[0372] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.) 10.2 parts by weight, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound 0.5 parts by weight, KF945 non-hydroxyl-free non-reactive silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 parts by weight, Irganox1010 (manufactured by BASF) as an antioxidant 0.5 parts by weight, and ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst 0.03 parts by weight were diluted with ethyl acetate to obtain a urethane-based adhesive solution with an overall solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (48). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (48). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0373] [Example 49]

[0374] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX:C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound, 0.05 parts by weight of hydroxyl-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (49). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (49). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0375] [Example 50]

[0376] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. HX: C / HX (manufactured by Nippon Polyurethane Co., Ltd.) 10.2 parts by weight, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound 0.5 parts by weight, KF615A non-reactive silicone oil without hydroxyl groups (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.025 parts by weight, Irganox1010 (manufactured by BASF) as an antioxidant 0.5 parts by weight, and ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst 0.03 parts by weight were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (50). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (50). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 4.

[0377] [Example 51]

[0378] The mixture comprises 50 parts by weight of a urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, and an isocyanate compound (Coronate) as a crosslinking agent. 10.2 parts by weight of HX:C / HX (manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) as an ionic compound, 0.01 parts by weight of hydroxyl-free non-reactive silicone oil KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by weight of Irganox1010 (manufactured by BASF) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were diluted with ethyl acetate to obtain a urethane-based adhesive solution with a total solid content of 50% by weight. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was then cured at a drying temperature of 130°C for 3 minutes to create an adhesive layer formed from the adhesive composition (51). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (51). The film was cured at room temperature for 5 days and evaluated. The release liner was peeled off just before the evaluation. The results are shown in Table 4.

[0379] [Example 52]

[0380] The mixture comprises 50 parts by weight of urethane prepolymer, 30 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 20 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 10.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AS110, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), and fluorinated oligomer Megafac. A urethane-based adhesive solution was prepared by diluting 0.1 parts by weight of F-563 (manufactured by DIC Corporation), 0.025 parts by weight of KF615A (manufactured by Shin-Etsu Chemical Co., Ltd.) (a non-hydroxyl-free non-reactive silicone oil), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) (an antioxidant), and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industries, Ltd.) (a catalyst) with ethyl acetate as the total solid content of 50% by weight. The urethane-based adhesive solution was then coated onto a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a thickness of 75 μm after drying. The substrate was cured and dried at a drying temperature of 130°C for 3 minutes to form an adhesive layer of the adhesive composition (52). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (52). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 4.

[0381] [Comparative Example 1]

[0382] A urethane-based adhesive solution was prepared by diluting 100 parts by weight of a urethane prepolymer, 2.9 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate as the total solid content of 50% by weight. The urethane-based adhesive solution was then coated onto a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Co., Ltd.) to a thickness of 75 μm after drying, and cured at a drying temperature of 130°C for 3 minutes to form an adhesive layer of the adhesive composition (C1). Next, a 25 μm thick release sheet made of polyester resin (trade name "MRF25", 25 μm thick, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the obtained adhesive layer to obtain a surface protective film (C1). The film was cured at room temperature for 5 days and evaluated. The release sheet was peeled off just before the evaluation. The results are shown in Table 5.

[0383] [Comparative Example 2]

[0384] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 35 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP250 (manufactured by Sanyo Chemical Co., Ltd., Mn=250), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C2). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with a silicone-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C2). The film was cured at room temperature for 5 days and evaluated. The release liner was peeled off just before evaluation. The results are shown in Table 5.

[0385] [Comparative Example 3]

[0386] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 40 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 10 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), an isocyanate compound (manufactured ... Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C3). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with a silicone-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C3). The film was cured at room temperature for 5 days and evaluated. The release liner was peeled off just before evaluation. The results are shown in Table 5.

[0387] [Comparative Example 4]

[0388] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 40 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 5 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 5 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Co., Ltd., Mn=1000), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C4). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with a silicone-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C4). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 5.

[0389] [Comparative Example 5]

[0390] A urethane-based adhesive solution was prepared by diluting 50 parts by weight of a urethane prepolymer, 24 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 26 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), an isocyanate compound, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C5). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C5). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 5.

[0391] [Comparative Example 6]

[0392] A urethane-based adhesive solution was obtained by diluting 50 parts by weight of a urethane prepolymer, 50 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 6.0 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industries Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of adhesive composition (C6). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C6). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 5.

[0393] [Comparative Example 7]

[0394] A urethane-based adhesive solution was obtained by diluting 30 parts by weight of urethane prepolymer, 70 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 7.2 parts by weight of isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industries Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C7). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C7). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 5.

[0395] [Comparative Example 8]

[0396] A urethane-based adhesive solution was obtained by diluting 10 parts by weight of a urethane prepolymer, 90 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 8.5 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industries Co., Ltd.), with the total solid content being 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C8). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C8). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 5.

[0397] [Comparative Example 9]

[0398] A urethane-based adhesive solution was prepared by diluting 30 parts by weight of a urethane prepolymer, 40 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 30 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 13.4 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C9). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with an organosilicon-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C9). The film was cured at room temperature for 5 days and evaluated. The release liner was peeled off just before evaluation. The results are shown in Table 5.

[0399] [Comparative Example 10]

[0400] A urethane-based adhesive solution was prepared by diluting 10 parts by weight of a urethane prepolymer, 50 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), a polyol having three hydroxyl groups, 40 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), a polyol having three hydroxyl groups, 16.7 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), a crosslinking agent, 0.5 parts by weight of Irganox 1010 (manufactured by BASF), an antioxidant, and 0.03 parts by weight of iron acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), a catalyst, with a total solid content of 50% by weight, with ethyl acetate. Then, a urethane-based adhesive solution was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) with a dried thickness of 75 μm. The substrate was cured at 130°C for 3 minutes to create an adhesive layer of the adhesive composition (C10). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with a silicone-treated surface was bonded to the surface of the adhesive layer to obtain a surface protective film (C10). The film was cured at room temperature for 5 days and evaluated. The release liner was removed just before evaluation. The results are shown in Table 5.

[0401] [Comparative Example 11]

[0402] A polyol containing three hydroxyl groups, namely Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), was diluted with ethyl acetate to obtain a urethane-based adhesive solution. The polyols were: 50 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10000), 50 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), 50 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Co., Ltd., Mn=3000), 19.3 parts by weight of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.), 0.5 parts by weight of Irganox 1010 (manufactured by BASF Co., Ltd.), 0.03 parts by weight of ferric acetylacetone (manufactured by Nippon Chemical Industry Co., Ltd.), with a total solid content of 50% by weight. Next, it was attempted to coat a urethane-based adhesive solution onto a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) and dry it to create an adhesive layer with a thickness of 75 μm. However, the low viscosity of the urethane-based adhesive solution prevented such a thick film from being achieved. The results are shown in Table 5.

[0403] [Table 1]

[0404]

[0405] [Table 2]

[0406]

[0407] [Table 3]

[0408]

[0409] [Table 4]

[0410]

[0411] [Table 5]

[0412]

[0413] [Examples 53-104]

[0414] For each surface protective film with an isolator obtained in Examples 1 to 52, the isolator is peeled off and attached to a polarizing plate (manufactured by Nitto Denko Corporation, trade name "TEG1465DUHC") which is an optical component, to obtain an optical component with a surface protective film attached.

[0415] [Examples 105-156]

[0416] For each surface protective film with an insulator obtained in Examples 1 to 52, the insulator is peeled off and attached to a conductive film (manufactured by Nitto Denko Corporation, trade name "ELECRYSTA V270L-TFMP") which is an electronic component, to obtain an electronic component with a surface protective film attached.

[0417] Industrial availability

[0418] The surface protective film of the present invention can be used for any suitable application. Preferably, the surface protective film of the present invention is preferably used for the surface protection of optical components and electronic components.

[0419] Explanation of reference numerals in the attached figures

[0420] 1. Substrate layer

[0421] 2 Adhesive layer

[0422] 10 Surface protective film

Claims

1. A surface protective film comprising a urethane-based adhesive layer, The urethane-based adhesive layer is composed of an urethane-based adhesive, which is formed from an urethane-based adhesive composition. The urethane-based adhesive composition comprises urethane prepolymer P, polyol A, and polyfunctional isocyanate compound B. The urethane-based adhesive composition contains an ionic compound, which is present in an amount of 0.05% to 10% by weight relative to the total amount of the urethane prepolymer P and the polyol A. The urethane prepolymer P is a urethane prepolymer obtained by reacting a polyester polyol (p1) with a number average molecular weight of 500-5000, a polyether polyol (p2) with a number average molecular weight of 1000-5000, and an organic polyisocyanate compound (p3). The weight ratio of the urethane prepolymer P to the polyol A is P:A = (50-90):(10-50). The polyol A contains one or more first polyols A1 and one or more second polyols A2. The first polyol A1 is a polyether polyol with 3 to 6 OH groups and a number-average molecular weight Mn of 5000 to 20000. The second polyol A2 is a polyether polyol with 3 to 6 OH groups and a number-average molecular weight Mn of 300 to 4000. The total content of the first polyol A1 and the second polyol A2 in the polyol A is 98% to 100% by weight. The weight ratio of the first polyol A1 to the second polyol A2 is 1.0 ≤ (A1 / A2) ≤ 2.

0. The polyfunctional isocyanate compound B in the urethane-based adhesive composition is present in a proportion of 2.5 to 40 parts by weight relative to the urethane prepolymer P100.

2. The surface protective film according to claim 1, wherein, The urethane-based adhesive composition comprises at least one selected from the group consisting of fluorinated additives and silicone additives, and the total amount of the fluorinated additive and the silicone additive is 0.01% to 10% by weight relative to the total amount of the urethane prepolymer P and the polyol A.

3. The surface protective film according to claim 1 or 2, wherein, When the urethane adhesive layer is bonded to a glass plate and peeled from the glass plate at 23°C for 30 minutes at a peel angle of 180 degrees and a peel speed of 300 mm / min, the peel force is 0.5 gf / 25 mm to 2.0 gf / 25 mm.

4. The surface protective film according to claim 1 or 2, wherein, After the urethane adhesive layer is bonded to a glass plate and peeled off from the glass plate at 23°C for 24 hours at a peel angle of 180 degrees and a peel speed of 0.3 m / min, the residual adhesion rate to the glass plate is more than 80%.

5. An optical component having a surface protective film attached to it according to any one of claims 1 to 4.

6. An electronic component having a surface protective film attached as described in any one of claims 1 to 4.

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