JP2024084496A - Surface protective film - Google Patents

Abstract

To provide a surface protective film comprising an adhesive layer mainly used for sticking to exposed surfaces of an optical member and an electronic member in order to prevent surface damage of the optical member and the electronic member in the cases such as processing, an assembly, an inspection, and transportation, in a production process of the optical member and the electronic member, while achieving excellent light releasability at an initial stage of sticking and suppressing rise of peel strength with time.SOLUTION: A surface protective film by the embodiment of the present invention is a surface protective film comprising an adhesive layer, and an adhesive constituting the adhesive layer is formed from an adhesive composition, the adhesive composition contains a urethane prepolymer (A), a fluorine-based compound (B), a silicone-based compound (C), and a fatty acid ester (D), and surface free energy of a surface of the adhesive layer as opposed to diiodomethane is 0.1-8.0 mJ/m2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a surface protection film.

In the manufacturing process of optical and electronic components, a surface protection film is generally applied to the exposed surface of the optical or electronic component to prevent the surface of the optical or electronic component from being damaged during processing, assembly, inspection, transportation, etc. Such a surface protection film is peeled off from the optical or electronic component when surface protection is no longer necessary (Patent Document 1).

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

In addition, optical and electronic components are generally expensive and easily damaged. For this reason, it is important that the surface protection film attached to the exposed surface of an optical or electronic component does not damage the optical or electronic component when it is peeled off, and from this perspective, excellent easy peelability is required.

As a means of making surface protection films easier to peel off, a technique has been reported in which a fluorine-based compound or a silicone-based compound is added to the adhesive composition that forms the adhesive that constitutes the adhesive layer.

Patent Documents 2 and 3 report a technology that allows for the development of ultra-light peelability by incorporating a fluorine-based compound and/or a silicone-based compound into the adhesive composition that forms the urethane-based adhesive.

Patent Document 4 reports a technology for a surface protection film that does not peel easily from an adherend, that prevents heavy peeling over time even if the initial peel strength after application to an adherend is large, and that causes little contamination of the adherend surface when applied to the adherend, by including a fluorine-based compound and/or a silicone-based compound in an adhesive composition that forms a urethane-based adhesive, and further including a fatty acid ester.

Patent Document 5 reports a technology for a surface protection film that does not peel easily from an adherend, that can sufficiently suppress severe peeling over time even when stored for long periods in harsh environments, and that causes sufficiently low contamination of the adherend surface when attached to the adherend, by including a fluorine-based compound and/or a silicone-based compound in an adhesive composition that forms a urethane-based adhesive, and further including a low molecular weight polyol.

Here, urethane-based adhesives are known as preferred adhesives constituting the adhesive layer of a surface protection film whose main purpose is to attach it to the exposed surface of an optical component or electronic component. As is generally well known, there are two types of manufacturing methods for urethane-based resins used to obtain urethane-based adhesives: the "one-shot method," in which a urethane-based resin is produced by directly reacting a polyol with a multifunctional isocyanate without using a urethane prepolymer, and the "prepolymer method," in which a urethane-based resin is produced by reacting a urethane prepolymer with a multifunctional isocyanate.

The "one-shot method" uses a polyol with a number average molecular weight of around 10,000, which is directly cured by reaction with a polyfunctional isocyanate, resulting in a high crosslink density and ensuring easy peelability. However, the "one-shot method" has a problem in that the viscosity of the adhesive solution is low, making it unsuitable for thick film formation. On the other hand, the "prepolymer method" has a problem in that the viscosity of the adhesive solution is high, making it suitable for thick film formation. However, the "prepolymer method" has a problem in that the crosslink density of the adhesive obtained by curing by reaction with a polyfunctional isocyanate is low, making it difficult to achieve easy peelability.

Patent Documents 2 and 3 report embodiments using a fluorine-based compound when a urethane prepolymer is used as the base polymer (Examples 7 to 15). Patent Document 4 reports embodiments using a fluorine-based compound and a fatty acid ester (Examples 1 to 12, 14, and 15) and an embodiment using a silicone-based compound and a fatty acid ester (Example 13) when a urethane prepolymer is used as the base polymer. Patent Document 5 reports embodiments using a fluorine-based compound, a low molecular weight polyol, and a fatty acid ester (Examples 1 to 3) and an embodiment using a silicone-based compound and a low molecular weight polyol (Example 13) when a urethane prepolymer is used as the base polymer.

However, the inventors' investigations revealed that the embodiments reported in Patent Documents 2 to 5 do not adequately achieve both excellent easy peelability at the initial stage of application and suppression of an increase in peel strength over time, and in particular, do not achieve sufficient performance for applications in which the film is attached to exposed surfaces of optical or electronic components to prevent scratches on the surfaces of the optical or electronic components during processing, assembly, inspection, transportation, etc., in the manufacturing process of the optical or electronic components.

On the other hand, surface protection films, optical components, and electronic components usually have high electrical insulation and generate static electricity due to friction or peeling. For this reason, static electricity is also generated when peeling off a surface protection film from an optical component or electronic component to which the surface protection film is attached. If this static electricity remains, for example, when a voltage is applied to the liquid crystal, the orientation of the liquid crystal molecules is lost or the panel is damaged. In addition, the presence of static electricity can attract dust and reduce workability. In order to prevent such static electricity, a technology for applying an antistatic treatment to the surface protection film has been reported. For example, a technology for imparting an antistatic function by forming an antistatic layer or applying an antistatic coating as the surface layer (topcoat layer or back layer) of the surface protection film has been reported (Patent Documents 6 and 7).

In addition, in order to impart antistatic properties to the adhesive layer itself of the surface protection film, a technique has been reported in which an ionic compound such as an alkali metal salt or an ionic liquid that functions as an antistatic agent is contained in the adhesive layer, and a technique has been reported in which an antistatic layer is provided between the substrate and the adhesive layer (Patent Document 8).

However, in the above-mentioned technology, the antistatic performance depends on the amount of antistatic agent. Therefore, the more the amount of antistatic agent is increased, the more the adherend becomes contaminated, which can lead to process defects such as peeling when another member is attached after the surface protection film is peeled off, and there is also the problem of an additional process being required to provide an antistatic layer between the substrate and the adhesive layer.

Patent No. 6613516 Patent No. 6368810 Japanese Patent No. 6648168 Patent No. 7137961 Patent No. 7142482 Patent No. 4170102 Japanese Patent No. 4920613 JP 2018-168373 A

The present invention aims to provide a surface protection film including an adhesive layer, the main use of which is to attach to the exposed surface of an optical or electronic component to prevent the surface of the optical or electronic component from being scratched during processing, assembly, inspection, transportation, etc., in the manufacturing process of the optical or electronic component, and which exhibits excellent easy peelability at the initial stage of attachment and is capable of suppressing an increase in peel strength over time.

In addition, when the adhesive composition forming the adhesive constituting the adhesive layer contains an ionic compound, the object of the present invention is to provide a surface protection film that achieves the above object, exhibits excellent antistatic performance, and can suppress contamination of the adherend even when stored in an attached state for several days.

[1] A surface protection film according to an embodiment of the present invention is a surface protection film including a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition includes a urethane prepolymer (A), a fluorine-based compound (B), a silicone-based compound (C), and a fatty acid ester (D), and the surface of the pressure-sensitive adhesive layer has a surface free energy with respect to diiodomethane of 0.1 mJ/ ^m2 to 8.0 mJ/ ^m2 .
[2] In the surface protective film according to the above [1], the content ratio of the silicone compound (C) per 100 parts by weight of the urethane prepolymer (A) may be 0.02 to 3 parts by weight.
[3] In the surface protective film according to the above [1] or [2], the pressure-sensitive adhesive layer contained in the surface protective film may be attached to the surface of an acrylic plate and left at a temperature of 23° C. for 30 minutes, and then the surface protective film is peeled off from the acrylic plate surface at a peel angle of 180° and a peel speed of 300 mm/min at a temperature of 23° C., where P1 is the peel force; and P2 is the peel force when the pressure-sensitive adhesive layer contained in the surface protective film is attached to the surface of an acrylic plate and left at a temperature of 23° C. for 1 week, and then the surface protective film is peeled off from the acrylic plate surface at a peel angle of 180° and a peel speed of 300 mm/min at a temperature of 23° C., where P2 is the peel force. A rate of increase in peel force over time (1) calculated by (peel force P2/peel force P1)×100(%) may be 150% or less.
[4] In the surface protective film according to any one of [1] to [3] above, when the pressure-sensitive adhesive layer contained in the surface protective film is attached to the surface of an acrylic plate and left at a temperature of 23° C. for 30 minutes, and then the surface protective film is peeled off from the acrylic plate surface at a temperature of 23° C. at a peel angle of 180° and a peel speed of 300 mm/min, the peel force is defined as P1, and when the pressure-sensitive adhesive layer contained in the surface protective film is attached to the surface of an acrylic plate and left at a temperature of 50° C. for 1 day, and then the surface protective film is peeled off from the acrylic plate surface at a temperature of 23° C. at a peel angle of 180° and a peel speed of 300 mm/min, the peel force is defined as P3. A peel force increase rate (2) over time of the peel force calculated by (peeling force P3/peeling force P1)×100(%) may be 250% or less.
[5] In the surface protective film according to any one of [1] to [4] above, the amount of black spots in the pressure-sensitive adhesive layer contained in the surface protective film may be 5 or ^less per 100 cm2.
[6] In the surface protective film according to any one of the above [1] to [5], the pressure-sensitive adhesive composition may contain an ionic compound (E).
[7] In the surface protective film according to the above [6], the ionic compound (E) may have a molecular weight of 350 or less.
[8] In the surface protective film according to the above [6] or [7], a peeling electrification voltage from an acrylic plate may be 2 kV or less.
[9] In the surface protective film according to any one of [6] to [8] above, the content ratio of the fatty acid ester (D) relative to 100 parts by weight of the urethane prepolymer (A) may be 0.01 parts by weight to 28 parts by weight.
[10] An optical member according to an embodiment of the present invention has the surface protection film according to any one of [1] to [9] adhered thereto.
[11] An electronic device according to an embodiment of the present invention has a surface protection film according to any one of [1] to [9] above attached thereto.

According to the present invention, it is possible to provide a surface protection film including an adhesive layer, the main use of which is to attach to the exposed surface of an optical or electronic component to prevent the surface of the optical or electronic component from being scratched during processing, assembly, inspection, transportation, etc., in the manufacturing process of the optical or electronic component, and which exhibits excellent easy peelability at the initial stage of attachment and is capable of suppressing an increase in peel strength over time.

In addition, according to the present invention, when the adhesive composition forming the adhesive constituting the adhesive layer contains an ionic compound, it is possible to provide a surface protection film that can exhibit the above-mentioned effects, exhibit excellent antistatic performance, and suppress contamination of the adherend even when the film is stored in an attached state for several days.

1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention.

When the term "weight" appears in this specification, it may be read as "mass," which is the commonly used SI unit of weight.

In this specification, the term "(meth)acrylic" means "acrylic and/or methacrylic", the term "(meth)acrylate" means "acrylate and/or methacrylate", the term "(meth)allyl" means "allyl and/or methallyl", and the term "(meth)acrolein" means "acrolein and/or methacrolein".

<<A. Surface protection film>>
The surface protection film according to the embodiment of the present invention includes a pressure-sensitive adhesive layer.

As long as the surface protection film contains a pressure-sensitive adhesive layer, it may contain any other appropriate components as long as the effects of the present invention are not impaired. Typically, the surface protection film of the present invention contains a substrate layer and a pressure-sensitive adhesive layer.

Figure 1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention. In Figure 1, the surface protection film 10 comprises a base layer 1 and an adhesive layer 2. In Figure 1, the base layer 1 and the adhesive layer 2 are directly laminated.

In FIG. 1, the surface of the adhesive layer 2 opposite the substrate layer 1 may be provided with any suitable release liner (sometimes called a release sheet or separator) for protection until use (not shown). Examples of release liners include release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is silicone-treated, and release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin.

Examples of plastic films that can be used as liner substrates include polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, and ethylene-vinyl acetate copolymer films.

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

The thickness of the surface protection film is preferably 5 μm to 500 μm, more preferably 10 μm to 450 μm, even more preferably 15 μm to 400 μm, and particularly preferably 20 μm to 300 μm.

In the surface protection film according to the embodiment of the present invention, the surface free energy of the pressure-sensitive adhesive layer surface with respect to diiodomethane is preferably 0.1 mJ/m ² to 8.0 mJ/m ² , more preferably 0.1 mJ/m ² to 7.5 mJ/m ² , even more preferably 0.1 mJ/m ² to 7.0 mJ/m ² , particularly preferably 0.1 mJ/m ² to 6.5 mJ/m ² , and most preferably 0.1 mJ/m ² to 6.0 mJ/m ^2. If the surface free energy of the pressure-sensitive adhesive layer surface with respect to diiodomethane is within the above range, the effects of the present invention can be more effectively exhibited. If the surface free energy of the pressure-sensitive adhesive layer surface with respect to diiodomethane is outside the above range, for example, there is a risk of an increase in peel force over time.

As described below, the surface free energy of the adhesive layer surface with respect to diiodomethane can be easily measured, and the effects of the present invention can be more effectively achieved by designing the adhesive layer so that the surface free energy falls within the above-mentioned range, such as suppressing the increase in peel force over time. A typical specific means for designing such an adhesive layer is to select a urethane prepolymer (A) as the base polymer and appropriately select and use a fluorine-based compound (B), a silicone-based compound (C), and a fatty acid ester (D) as components contained in the adhesive composition used to form the adhesive that constitutes the adhesive layer. These selections are actions that can be performed by a person skilled in the art without excessive trial and error.

In the surface protection film according to the embodiment of the present invention, the adhesive layer contained in the surface protection film is attached to the surface of an acrylic plate, and the surface protection film is left at a temperature of 23° C. for 30 minutes. After that, the surface protection film is peeled from the surface of the acrylic plate at a temperature of 23° C. at a peel angle of 180 degrees and a peel speed of 300 mm/min. The peel force P1 is preferably 3.0 gf/25 mm or less, more preferably 2.5 gf/25 mm or less, even more preferably 2.3 gf/25 mm or less, even more preferably 2.0 gf/25 mm or less, particularly preferably 1.8 gf/25 mm or less, and most preferably 1.7 gf/25 mm or less. If the peel force P1 is within the above range, the surface protection film according to the embodiment of the present invention can exhibit excellent light peelability at the initial stage of application. In order to prevent unintended peeling during the manufacturing process, etc., the lower limit of the peel force P1 is preferably 0.5 gf/25 mm or more. The method for measuring the peel force P1 will be described later.

In the surface protection film according to the embodiment of the present invention, the adhesive layer contained in the surface protection film is attached to the surface of an acrylic plate, and the surface protection film is left at a temperature of 23° C. for one week. After that, the surface protection film is peeled from the surface of the acrylic plate at a peel angle of 180° and a peel speed of 300 mm/min at a temperature of 23° C. The peel force P2 is preferably 7.0 gf/25 mm or less, more preferably 5.0 gf/25 mm or less, even more preferably 4.0 gf/25 mm or less, even more preferably 3.5 gf/25 mm or less, particularly preferably 3.0 gf/25 mm or less, and most preferably 2.5 gf/25 mm or less. If the peel force P2 is within the above range, the surface protection film according to the embodiment of the present invention can exhibit excellent light peelability at the initial stage of application and can suppress an increase in the peel force over time. In order to prevent unintended peeling during the manufacturing process, etc., the lower limit of the peel force P2 is preferably 0.5 gf/25 mm or more. The method for measuring the peel force P2 will be described later.

In the surface protection film according to the embodiment of the present invention, the adhesive layer contained in the surface protection film is attached to the surface of an acrylic plate, and the surface protection film is left at a temperature of 50° C. for one day, and then the surface protection film is peeled from the surface of the acrylic plate at a temperature of 23° C. at a peel angle of 180 degrees and a peel speed of 300 mm/min. The peel force P3 is preferably 10.0 gf/25 mm or less, more preferably 8.0 gf/25 mm or less, even more preferably 6.0 gf/25 mm or less, even more preferably 5.0 gf/25 mm or less, particularly preferably 4.5 gf/25 mm or less, and most preferably 4.0 gf/25 mm or less. If the peel force P3 is within the above range, the surface protection film according to the embodiment of the present invention can exhibit excellent light peelability at the initial stage of application and can suppress an increase in the peel force over time. In order to prevent unintended peeling during the manufacturing process, etc., the lower limit of the peel force P3 is preferably 0.5 gf/25 mm or more. The method for measuring the peel force P3 will be described later.

In the surface protective film according to the embodiment of the present invention, the peel force increase rate over time (1) from the peel force P1 to the peel force P2 (peel force increase rate over time (1) (%) = (peel force P2/peel force P1) x 100 (%)) is preferably 150% or less, more preferably 130% or less, even more preferably 125% or less, and particularly preferably 120% or less. The lower limit of the peel force increase rate over time (1) is preferably as small as possible, and is preferably 100% or more. If the peel force increase rate over time (1) is within the above range, the surface protective film according to the embodiment of the present invention can further suppress the increase in peel force over time.

In the surface protective film according to the embodiment of the present invention, the rate of increase in peel force over time (2) from the peel force P1 to the peel force P3 (rate of increase in peel force over time (2) (%) = (peel force P3/peel force P1) x 100 (%)) is preferably 250% or less, more preferably 220% or less, even more preferably 200% or less, and particularly preferably 195% or less. The lower limit of the rate of increase in peel force over time (2) is preferably as small as possible, and is preferably 100% or more. If the rate of increase in peel force over time (2) is within the above range, the surface protective film according to the embodiment of the present invention can further suppress the increase in peel force over time.

In the surface protection film according to the embodiment of the present invention, the number of black spots generated in the pressure-sensitive adhesive layer contained in the surface protection film is preferably 5 or less per 100 cm ² , more preferably 3 or less per 100 cm ² , even more preferably 2 or less per 100 cm ² , particularly preferably 1 or less per 100 cm ² , and most preferably 0 per 100 cm ^2. If the number of black spots generated in the pressure-sensitive adhesive layer contained in the surface protection film is large, not only may the quality of the surface protection film be reduced, but in the case of a surface protection film that is to be bonded to, for example, an optical member or an electronic member, the inspectability may be reduced.

The surface protection film can be produced by any suitable method. Examples of such a production method include
(1) A method of applying a solution or a hot melt of a material for forming the adhesive layer onto a base layer,
(2) A method of applying a solution or a hot melt of a material for forming an adhesive layer onto a release liner to form an adhesive layer, and then transferring the adhesive layer onto a base layer;
(3) A method of forming and coating a material for forming a pressure-sensitive adhesive layer on a base layer by extrusion;
(4) A method of extruding a substrate layer and a pressure-sensitive adhesive layer in two layers or multiple layers,
(5) A method of laminating a single layer of a pressure-sensitive adhesive layer on a substrate layer or a method of laminating a double layer of a pressure-sensitive adhesive layer together with a laminate layer,
(6) A method of laminating a pressure-sensitive adhesive layer and a base layer-forming material such as a film or a laminate layer in a two-layer or multi-layer manner,
The above-mentioned manufacturing method can be used in accordance with any suitable manufacturing method.

Examples of coating methods that can be used include the roll coater method, comma coater method, die coater method, reverse coater method, silk screen method, and gravure coater method.

<A-1. Pressure-sensitive adhesive layer>
The pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive. The pressure-sensitive adhesive is formed from a pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive, and the pressure-sensitive adhesive is formed from a pressure-sensitive adhesive composition. In other words, the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition forms a layer shape to become the pressure-sensitive adhesive layer.

An adhesive can be defined as something formed from an adhesive composition. This is because an adhesive becomes an adhesive when an adhesive composition undergoes a crosslinking reaction, typically by heating or exposure to ultraviolet light, making it impossible to directly identify an adhesive by its structure, and there are circumstances that make it impractical to do so ("impossible/impractical circumstances"). Therefore, the definition of "something formed from an adhesive composition" appropriately identifies an adhesive as a "thing."

The adhesive layer may be formed by any suitable method. For example, an adhesive composition may be applied to any suitable substrate, heated and dried as necessary, and cured as necessary to form an adhesive layer on the substrate. The application method, heating and drying conditions, curing conditions, and the like may be appropriately selected from methods commonly known for forming adhesive layers.

The thickness of the adhesive layer is preferably 5 μm to 150 μm, more preferably 10 μm to 130 μm, even more preferably 30 μm to 120 μm, particularly preferably 50 μm to 100 μm, and most preferably 60 μm to 90 μm, in order to better exhibit the effects of the present invention.

The adhesive composition contains a urethane prepolymer (A), a fluorine-based compound (B), a silicone-based compound (C), and a fatty acid ester (D). In the present invention, the effects of the present invention can be achieved by using the urethane prepolymer (A), the fluorine-based compound (B), the silicone-based compound (C), and the fatty acid ester (D) in combination as components contained in the adhesive composition, preferably by selecting the type of each as described below and adjusting the amount used.

<A-1-1. Urethane prepolymer (A)>
The urethane prepolymer (A) corresponds to a polymer component generally called a base polymer as a component of a pressure-sensitive adhesive composition.

The content of the urethane prepolymer (A) in the adhesive composition is preferably 60% by weight to 99.9% by weight, more preferably 65% by weight to 99.9% by weight, even more preferably 70% by weight to 99.9% by weight, particularly preferably 75% by weight to 99.9% by weight, and most preferably 80% by weight to 99.9% by weight, calculated as solid content. When the content of the urethane prepolymer (A) in the adhesive composition is within the above range, calculated as solid content, the effects of the present invention can be more effectively achieved.

The urethane prepolymer (A) can typically react with a polyfunctional isocyanate compound (F) to form a urethane resin. More specifically, the urethane resin is preferably formed from a composition containing the urethane prepolymer (A) and the polyfunctional isocyanate compound (F), and more specifically, the urethane resin is formed by curing the composition containing the urethane prepolymer (A) and the polyfunctional isocyanate compound (F). As a method for curing the composition containing the urethane prepolymer (A) and the polyfunctional isocyanate compound (F) to form a urethane resin, any appropriate method can be used within the scope of the present invention, such as a urethane reaction method using bulk polymerization or solution polymerization.

As is well known, there are two types of manufacturing methods for urethane resins: the "one-shot method" in which a urethane resin is manufactured by directly reacting a polyol with a polyfunctional isocyanate without using a urethane prepolymer, and the "prepolymer method" in which a urethane resin is manufactured by reacting a urethane prepolymer with a polyfunctional isocyanate. In the present invention, the urethane prepolymer (A) as the base polymer means the urethane prepolymer that is reacted with the polyfunctional isocyanate in the "prepolymer method" and is different from the polyol that is reacted with the polyfunctional isocyanate in the "one-shot method".

The urethane prepolymer (A) may be of one type or of two or more types.

The number average molecular weight Mn of the urethane prepolymer (A) is preferably 3,000 to 1,000,000.

The urethane prepolymer (A) is typically a polymer obtained by reacting a polyol with a polyfunctional isocyanate compound, and has an isocyanate group at the molecular end.

The urethane prepolymer (A) is preferably a polyurethane polyol, and more preferably is obtained by reacting at least one selected from polyester polyol (a1) and polyether polyol (a2) with a polyfunctional isocyanate compound in the presence or absence of a catalyst.

The polyester polyol (a1) may be one type or two or more types.

The polyether polyol (a2) may be one type or two or more types.

As the polyester polyol (a1), polyester polyols that can be normally used in the production of polyurethane polyols can be appropriately used. Examples of such polyester polyols (a1) include polyester polyols obtained by reacting an acid component with a glycol component. Examples of the acid component include terephthalic acid, adipic acid, sebacic acid, and isophthalic acid. Examples of the glycol component include 3-methyl-1,5-pentanediol and trimethylolpropane.

The molecular weight of the polyester polyol (a1) can range from low to high. The number average molecular weight Mn of the polyester polyol (a1) is preferably 100 to 100,000. The amount of polyester polyol (a1) used is preferably 0 mol % to 90 mol % of the polyols constituting the polyurethane polyol.

As the polyether polyol (a2), a polyether polyol that can be normally used in the production of polyurethane polyols can be appropriately used. Examples of such polyether polyols (a2) include polyether polyols having two or more functional groups, such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol.

The molecular weight of the polyether polyol (a2) can range from low to high. The number average molecular weight Mn of the polyether polyol (a2) is preferably 100 to 100,000. The amount of polyether polyol (a2) used is preferably 0 mol % to 90 mol % of the polyols constituting the polyurethane polyol.

If necessary, polyether polyol (a2) can be used in combination by replacing a part of it with a glycol such as ethylene glycol or a polyamine such as ethylenediamine.

As the polyether polyol (a2), only a bifunctional polyether polyol may be used, or a polyether polyol having a number average molecular weight Mn of 100 to 100,000 and at least three hydroxyl groups per molecule may be used in part or in whole.

The polyfunctional isocyanate compound that can be reacted with the polyol to obtain the urethane prepolymer (A) may be one type or two or more types.

As the polyfunctional isocyanate compound, any suitable polyfunctional isocyanate compound that can be used in a urethane reaction can be used. Examples of such polyfunctional isocyanate compounds include polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanates, polyfunctional aromatic isocyanate compounds, and polyfunctional aromatic aliphatic isocyanate compounds.

Examples of polyfunctional aliphatic isocyanate compounds include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, 2,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

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

Examples of polyfunctional aromatic diisocyanate compounds include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, 4,4'-diphenylether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4',4"-triphenylmethane triisocyanate, dianisidine diisocyanate, and xylylene diisocyanate.

Examples of polyfunctional aromatic aliphatic isocyanate compounds include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate.

Examples of polyfunctional isocyanate compounds include trimethylolpropane adducts of the various polyfunctional isocyanate compounds described above, biuret adducts reacted with water, and trimers having an isocyanurate ring. These may also be used in combination.

The isocyanate groups of the polyfunctional isocyanate compound are preferably used in a molar ratio that is in excess of the hydroxyl groups of the polyol. The equivalent ratio of NCO groups to OH groups in the polyol and polyfunctional isocyanate compound that can be used to obtain the urethane prepolymer (A) is preferably 1.01 to 5.0, more preferably 1.1 to 3.0, even more preferably 1.1 to 2.0, particularly preferably 1.1 to 1.8, and most preferably 1.2 to 1.6, in terms of NCO groups/OH groups.

Any suitable catalyst may be used to obtain the urethane prepolymer (A). Examples of such catalysts include tertiary amine compounds and organometallic compounds.

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

Examples of organometallic compounds include tin compounds and non-tin compounds. Examples of tin compounds include dibutyltin dilaurate (DBTDL) and dioctyltin dilaurate (DOTDL). Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanium, and butoxytitanium trichloride; iron compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium compounds such as zirconium naphthenate.

When a catalyst is used in preparing the urethane prepolymer (A), the amount of the catalyst used is preferably 0.0001% by weight to 1.0% by weight, more preferably 0.001% by weight to 1.0% by weight, even more preferably 0.003% by weight to 1.0% by weight, and particularly preferably 0.005% by weight to 1.0% by weight, based on the total amount of the polyester polyol (a1), the polyether polyol (a2), and the polyfunctional isocyanate compound.

When a catalyst is used in preparing the urethane prepolymer (A), the reaction temperature is preferably less than 100°C, and more preferably 85°C to 95°C. If the temperature is above 100°C, it may become difficult to control the reaction rate and crosslinking structure.

When preparing the urethane prepolymer (A), it is not necessary to use a catalyst. In that case, the reaction temperature is preferably 100°C or higher, and more preferably 110°C or higher. In addition, when preparing the urethane prepolymer (A) without a catalyst, it is preferable to carry out the reaction for 3 hours or more.

Methods for preparing urethane prepolymer (A) include, for example, 1) a method in which a polyol, a catalyst, and a polyfunctional isocyanate compound are charged in a flask, and 2) a method in which a polyol and a catalyst are charged in a flask and a polyfunctional isocyanate compound is added dropwise. In method 2), after the polyfunctional isocyanate compound is added dropwise, additional polyol and polyfunctional isocyanate compound may be added. As a method for preparing urethane prepolymer (A), method 2) is preferred in terms of controlling the reaction.

Any suitable solvent may be used when preparing the urethane prepolymer (A). Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Of these solvents, toluene is preferred.

When preparing the urethane prepolymer (A), any appropriate other components may be used within the scope of not impairing the effects of the present invention. Examples of other components include antioxidants, UV absorbers, light stabilizers, resin components, tackifiers, crosslinking retarders, inorganic fillers, organic fillers, metal powders, pigments, foil-like materials, softeners, anti-aging agents, conductive agents, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, and lubricants. The other components may be one type only or two or more types. Among the other components, anti-deterioration agents such as antioxidants, UV absorbers, and light stabilizers are one of the preferred embodiments.

As the antioxidant, any appropriate antioxidant may be used as long as it does not impair the effects of the present invention. Examples of such antioxidants include radical chain inhibitors and peroxide decomposers. Examples of radical chain inhibitors include phenol-based antioxidants and amine-based antioxidants. Examples of peroxide decomposers include sulfur-based antioxidants and phosphorus-based antioxidants.

As the ultraviolet absorbing agent, any suitable ultraviolet absorbing agent may be used as long as it does not impair the effects of the present invention. Examples of such ultraviolet absorbing agents include benzophenone-based ultraviolet absorbing agents, benzotriazole-based ultraviolet absorbing agents, salicylic acid-based ultraviolet absorbing agents, anilide oxalate-based ultraviolet absorbing agents, cyanoacrylate-based ultraviolet absorbing agents, and triazine-based ultraviolet absorbing agents.

As the light stabilizer, any appropriate light stabilizer may be used as long as it does not impair the effects of the present invention. Examples of such light stabilizers include hindered amine light stabilizers and ultraviolet light stabilizers.

<A-1-2. Polyfunctional isocyanate compound (F)>
As described above, the urethane prepolymer (A) typically reacts with the polyfunctional isocyanate compound (F) to form a urethane resin. Therefore, the pressure-sensitive adhesive composition preferably contains the polyfunctional isocyanate compound (F). That is, the pressure-sensitive adhesive composition preferably contains the urethane prepolymer (A), the fluorine-based compound (B), the silicone-based compound (C), the fatty acid ester (D), and the polyfunctional isocyanate compound (F).

The polyfunctional isocyanate compound (F) may be one type or two or more types.

As the polyfunctional isocyanate compound (F), any suitable polyfunctional isocyanate compound that can be used in the urethane reaction can be used. As such a polyfunctional isocyanate compound (F), the polyfunctional isocyanate compound described above as a polyfunctional isocyanate compound that can be reacted with a polyol to obtain the urethane prepolymer (A) can be used. The polyfunctional isocyanate compound (F) that reacts with the urethane prepolymer (A) to become a urethane-based resin may be the same as or different from the polyfunctional isocyanate compound described above as a polyfunctional isocyanate compound that can be reacted with a polyol to obtain the urethane prepolymer (A).

The equivalent ratio of the NCO groups of the polyfunctional isocyanate compound (F) to the OH groups of the urethane prepolymer, expressed as NCO groups/OH groups, is preferably 1.0 to 2.7, more preferably 1.2 to 2.5, even more preferably 1.4 to 2.3, and particularly preferably 1.5 to 2.2. If the equivalent ratio of NCO groups/OH groups is within the above range, the effects of the present invention can be more effectively exhibited.

The content of the polyfunctional isocyanate compound (F) in the adhesive composition is preferably 1.0 to 15 parts by weight, more preferably 1.5 to 14 parts by weight, even more preferably 2.0 to 13 parts by weight, even more preferably 2.3 to 12 parts by weight, even more preferably 2.3 to 11 parts by weight, particularly preferably 2.5 to 18 parts by weight, and most preferably 2.5 to 10 parts by weight, per 100 parts by weight of the urethane prepolymer (A). If the content of the polyfunctional isocyanate compound (F) per 100 parts by weight of the urethane prepolymer (A) is within the above range, the effects of the present invention can be more effectively exhibited.

<A-1-3. Fluorine-based compound (B)>
As the fluorine-based compound (B), any appropriate fluorine-based compound may be adopted within a range that does not impair the effects of the present invention. The effects of the present invention can be exhibited by the pressure-sensitive adhesive composition containing the fluorine-based compound (B). If the pressure-sensitive adhesive composition does not contain the fluorine-based compound (B), there is a risk that excellent light peelability at the initial stage of attachment cannot be exhibited, or that an increase in peel strength over time cannot be suppressed.

The fluorine-based compound (B) may be one type or two or more types.

The content of the fluorine-based compound (B) in the adhesive composition is preferably 0.01 to 3.0 parts by weight, more preferably 0.05 to 2.0 parts by weight, even more preferably 0.1 to 1.5 parts by weight, particularly preferably 0.1 to 1.0 parts by weight, and most preferably 0.1 to 0.9 parts by weight, per 100 parts by weight of the urethane prepolymer (A). If the content of the fluorine-based compound (B) per 100 parts by weight of the urethane prepolymer (A) is within the above range, the effects of the present invention can be more effectively achieved. If the content of the fluorine-based compound (B) per 100 parts by weight of the urethane prepolymer (A) is outside the above range, there is a risk that excellent easy peelability at the beginning of application cannot be achieved, or that the increase in peel strength over time cannot be suppressed.

In order to further exert the effects of the present invention, the fluorine-based compound (B) is preferably a fluorine-based oligomer, more preferably an oligomer having a fluorine-containing group and a hydrophilic group and/or a lipophilic group, and even more preferably an oligomer having a fluorine-containing group, a hydrophilic group, and a lipophilic group.

Representative examples of the fluorine-containing group include fluorine-containing alkyl groups (e.g., CF ₃ -, etc.) and/or fluorine-containing alkylene groups (e.g., -CF ₂ -CF ₂ -, etc.). The hydrophilic group is a group having hydrophilicity, and hydrophilicity is translated into English as "hydrophilic" and is a property generally known to those skilled in the art as meaning "affinity for water" (see, for example, McGraw-Hill Scientific and Technical Dictionary (Revised 3rd Edition, Nikkan Kogyo Shimbun, Ltd.)). The lipophilic group is a group having lipophilicity, and lipophilicity is translated into English as "lipophilic" and is a property generally known to those skilled in the art as meaning "affinity for oil" (see, for example, McGraw-Hill Scientific and Technical Dictionary (Revised 3rd Edition, Nikkan Kogyo Shimbun, Ltd.)).

In terms of being able to further exert the effects of the present invention, the surface tension of the fluorine-based compound (B) in a 0.1% toluene solution (the surface tension of toluene is 27.9 mN/m) is preferably 19.0 mN/m to 25.9 mN/m, more preferably 22.0 mN/m to 25.7 mN/m, even more preferably 23.0 mN/m to 25.5 mN/m, particularly preferably 23.5 mN/m to 25.3 mN/m, and most preferably 24.0 mN/m to 25.0 mN/m. By adopting the above-mentioned specific fluorine-based compound as the fluorine-based compound (B), the effects of the present invention can be further exerted. In addition, by adopting the above-mentioned specific fluorine-based compound as the fluorine-based compound (B), the peeling electrification voltage can be sufficiently suppressed, excellent antistatic properties can be exerted, and the adhesive layer can exhibit excellent anchoring properties.

A particularly preferred embodiment of the fluorine-based compound (B) is an oligomer containing a fluorine-containing group, a hydrophilic group, and a lipophilic group, and has a surface tension of 19.0 mN/m to 25.9 mN/m when dissolved in 0.1% toluene (the surface tension of toluene is 27.9 mN/m). The surface tension is preferably 22.0 mN/m to 25.7 mN/m, more preferably 23.0 mN/m to 25.5 mN/m, even more preferably 23.5 mN/m to 25.3 mN/m, and particularly preferably 24.0 mN/m to 25.0 mN/m. By employing a specific fluorine-based compound as the fluorine-based compound (B), the effects of the present invention can be further enhanced. In addition, by using a specific fluorine-based compound such as the one described above as the fluorine-based compound (B), the peeling electrification voltage can be more sufficiently suppressed, better antistatic properties can be exhibited, and the adhesive layer can exhibit better anchoring properties.

An example of an oligomer having a fluorine-containing group and a hydrophilic group and/or a lipophilic group is the "Megafac Series" manufactured by DIC Corporation.

Among the "Megafac Series" manufactured by DIC Corporation, examples of oligomers containing a fluorine-containing group, a hydrophilic group, and a lipophilic group include:
"Megafac F-477" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 26.4 mN/m),
"Megafac F-553" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 26.4 mN/m),
"Megafac F-555-A" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% toluene = 20.4 mN/m),
"Megafac F-556" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 27.5 mN/m),
"Megafac F-559" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 26.1 mN/m),
"Megafac F-562" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.8 mN/m),
"Megafac F-565" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 27.6 mN/m),
"Megafac F-568" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.7 mN/m),
"Megafac F-571" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.8 mN/m),
Examples include:

Among the "Megafac Series" manufactured by DIC Corporation, examples of fluorine-based compounds having a surface tension of 19.0 mN/m to 25.9 mN/m when dissolved in 0.1% toluene (the surface tension of toluene is 27.9 mN/m) are:
"Megafac F-251" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 24.9 mN/m),
"Megafac F-253" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 21.9 mN/m),
"Megafac F-551-A" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 25.6 mN/m),
"Megafac F-552" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 24.9 mN/m),
"Megafac F-554" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 25.5 mN/m),
"Megafac F-555-A" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% toluene = 20.4 mN/m),
"Megafac F-560" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 20.2 mN/m),
"Megafac F-561" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 23 mN/m),
"Megafac F-562" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.8 mN/m),
"Megafac F-563" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 20.2 mN/m),
"Megafac F-568" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.7 mN/m),
"Megafac F-569" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 19.7 mN/m),
"Megafac F-570" (oligomer containing fluorine-containing groups, hydrophilic groups, lipophilic groups, and carboxyl groups, surface tension when dissolved in 0.1% toluene = 22.9 mN/m),
"Megafac F-571" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.8 mN/m),
"Megafac F-576" (fluorine-containing and lipophilic group-containing oligomer, surface tension when dissolved in 0.1% toluene = 24.8 mN/m),
Examples include:

Among the "Megafac Series" manufactured by DIC Corporation, examples of fluorine-based compounds which are oligomers containing a fluorine-containing group, a hydrophilic group, and a lipophilic group and have a surface tension of 19.0 mN/m to 25.9 mN/m when dissolved in 0.1% toluene (the surface tension of toluene is 27.9 mN/m) include:
"Megafac F-555-A" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, surface tension when dissolved in 0.1% toluene = 20.4 mN/m),
"Megafac F-562" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.8 mN/m),
"Megafac F-568" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.7 mN/m),
"Megafac F-570" (oligomer containing fluorine-containing groups, hydrophilic groups, lipophilic groups, and carboxyl groups, surface tension when dissolved in 0.1% toluene = 22.9 mN/m),
"Megafac F-571" (oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups; surface tension when dissolved in 0.1% toluene = 24.8 mN/m),
Examples include:

<A-1-4. Silicone compound (C)>
As the silicone-based compound (C), any suitable silicone-based compound can be adopted within a range that does not impair the effects of the present invention. The adhesive composition contains the silicone-based compound (C), and thus the effects of the present invention can be exhibited. If the adhesive composition does not contain the silicone-based compound (C), there is a risk that excellent light peelability at the initial stage of attachment cannot be exhibited, or that the increase in peel strength over time cannot be suppressed.

The silicone-based compound (C) may be one type or two or more types.

When the adhesive composition does not contain the ionic compound (E) described below, the content ratio of the silicone-based compound (C) in the adhesive composition is preferably 0.001 to 20 parts by weight, more preferably 0.005 to 10 parts by weight, even more preferably 0.01 to 5 parts by weight, even more preferably 0.01 to 2 parts by weight, even more preferably 0.01 to 1 part by weight, even more preferably 0.01 to 0.5 parts by weight, particularly preferably 0.01 to 0.1 parts by weight, and most preferably more than 0.01 parts by weight and less than 0.1 parts by weight. When the adhesive composition does not contain the ionic compound (E) described below, the effect of the present invention can be more effectively achieved if the content ratio of the silicone-based compound (C) to 100 parts by weight of the urethane prepolymer (A) is within the above range. If the adhesive composition does not contain the ionic compound (E) described below, and the content ratio of the silicone-based compound (C) to 100 parts by weight of the urethane prepolymer (A) is outside the above range, there is a risk that excellent easy peelability at the initial stage of application will not be achieved, and that the increase in peel strength over time will not be suppressed. Also, if the adhesive composition does not contain the ionic compound (E) described below, and the content ratio of the silicone-based compound (C) to 100 parts by weight of the urethane prepolymer (A) is too high outside the above range, there is a risk that the adherend will be contaminated after the surface protection film is applied to the adherend and peeled off.

When the adhesive composition contains an ionic compound (E) described below, the content ratio of the silicone-based compound (C) in the adhesive composition is preferably 0.001 to 20 parts by weight, more preferably 0.01 to 10 parts by weight, even more preferably 0.01 to 7 parts by weight, even more preferably 0.02 to 4 parts by weight, particularly preferably 0.03 to 2 parts by weight, and most preferably more than 0.03 parts by weight and 1 part by weight or less, relative to 100 parts by weight of the urethane prepolymer (A). When the adhesive composition contains an ionic compound (E) described below, the effects of the present invention can be more effectively achieved if the content ratio of the silicone-based compound (C) relative to 100 parts by weight of the urethane prepolymer (A) is within the above range. When the adhesive composition contains an ionic compound (E) described below, if the content ratio of the silicone-based compound (C) to 100 parts by weight of the urethane prepolymer (A) is outside the above range, there is a risk that excellent easy peelability at the initial stage of application will not be achieved, and the increase in peel strength over time will not be suppressed. Also, when the adhesive composition contains an ionic compound (E) described below, if the content ratio of the silicone-based compound (C) to 100 parts by weight of the urethane prepolymer (A) is too high outside the above range, there is a risk that the adherend will be contaminated after the surface protection film is applied to the adherend and peeled off.

Examples of silicone-based compounds (C) include reactive silicone oils and non-reactive silicone oils.

Examples of reactive silicone oils include side-chain reactive silicone oils in which an organic group is bonded as a side chain to a Si atom that is used for siloxane bonding; both-end reactive silicone oils in which an organic group is bonded to a Si atom located at both ends of the structure; one-end reactive silicone oils in which an organic group is bonded to only one of the Si atoms located at both ends of the structure; and both-end side-chain reactive silicone oils in which an organic group is bonded as a side chain to a Si atom that is used for siloxane bonding and an organic group is bonded to a Si atom located at both ends of the structure.

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

Examples of the reactive silicone oils include amino-modified reactive silicone oils at both ends, epoxy-modified reactive silicone oils at both ends, carbinol-modified reactive silicone oils at both ends, methacryl-modified reactive silicone oils at both ends, polyether-modified reactive silicone oils at both ends, mercapto-modified reactive silicone oils at both ends, carboxyl-modified reactive silicone oils at both ends, phenol-modified reactive silicone oils at both ends, silanol-modified reactive silicone oils at both ends, acrylic-modified reactive silicone oils at both ends, and carboxylic anhydride-modified reactive silicone oils at both ends. Commercially available products include various silicone oils available as reactive silicone oils at both ends manufactured by Shin-Etsu Chemical Co., Ltd. In particular, carbinol-modified reactive silicone oils at both ends, such as "KF-6000", "KF-6001", "KF-6002", "KF-6003", and "KF-6028" manufactured by Shin-Etsu Chemical Co., Ltd., can be preferably used.

The carbinol-modified double-ended reactive silicone oil preferably has a hydroxyl value of 1 mgKOH/g to 100 mgKOH/g, more preferably 10 mgKOH/g to 90 mgKOH/g, even more preferably 20 mgKOH/g to 80 mgKOH/g, and particularly preferably 30 mgKOH/g to 70 mgKOH/g, in order to better demonstrate the effects of the present invention.

Examples of single-end reactive silicone oils include single-end reactive silicone oils of a single-end reactive modified type, and single-end reactive silicone oils of an average single-end carboxyl modified type. Examples of commercially available products include various silicone oils available as single-end reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. In particular, carbinol-modified single-end reactive silicone oils such as "X-22-170BX", "X-22-170DX", and "X-22-4015" manufactured by Shin-Etsu Chemical Co., Ltd. are preferably used.

The carbinol-modified single-end reactive silicone oil preferably has a hydroxyl value of 1 mgKOH/g to 100 mgKOH/g, more preferably 10 mgKOH/g to 90 mgKOH/g, even more preferably 20 mgKOH/g to 80 mgKOH/g, and particularly preferably 30 mgKOH/g to 70 mgKOH/g, in order to better demonstrate the effects of the present invention.

Examples of side chain both-end reactive silicone oils include side chain both-end reactive silicone oils with amino and methoxy modified side chains, and epoxy modified side chain both-end reactive silicone oils. Examples of commercially available products include various silicone oils available as side chain both-end reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

Examples of non-reactive silicone oils include side-chain non-reactive silicone oils in which an organic group is bonded as a side chain to the Si atom that is used for the siloxane bond, and double-end non-reactive silicone oils in which organic groups are bonded to the Si atoms at both ends of the structure.

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, higher fatty acid-containing side-chain non-reactive silicone oils, and phenyl-modified side-chain non-reactive silicone oils. Commercially available products include, for example, the various silicone oils available as side-chain non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. In particular, polyether-modified side-chain non-reactive silicone oils such as "KF-351A", "KF-352A", "KF-353", "KF-354L", "KF-355A", "KF-615A", "KF-945", "KF-640", "KF-642", "KF-643", "KF-644", "KF-6020", "KF-6204", and "X-22-4515" manufactured by Shin-Etsu Chemical Co., Ltd. are preferably used.

Among polyether-modified side-chain non-reactive silicone oils, those with an HLB value of preferably 8 or more, more preferably 9 or more, and even more preferably 10 or more are preferred, as they can further reduce adhesive residue. 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).

Examples of both-end non-reactive silicone oils include polyether-modified both-end non-reactive silicone oils. Examples of commercially available products include various silicone oils available as both-end non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. In particular, polyether-modified both-end non-reactive silicone oils such as "KF-6004" manufactured by Shin-Etsu Chemical Co., Ltd. are preferably used.

As the silicone-based compound (C), in addition to the above, any suitable silicone-based compound known in the art may be used. Examples of such silicone-based compounds include siloxane bond-containing polymers other than those described above, hydroxyl group-containing silicone-based compounds other than those described above, and crosslinkable functional group-containing silicone-based compounds other than those described above.

Examples of commercially available siloxane bond-containing polymers other than those mentioned above include the product name "LE-302" (manufactured by Kyoeisha Chemical Co., Ltd.), the BYK series leveling agents manufactured by BYK Japan Co., Ltd., the AC series leveling agents manufactured by Algin Chemie, the Polyflow series leveling agents manufactured by Kyoeisha Chemical Co., Ltd., the KP series leveling agents manufactured by Shin-Etsu Chemical Co., Ltd., and the leveling agents manufactured by Dow Toray Co., Ltd. (such as "LP-7001", "LP-7002", "8032 ADDITIVE", "57 ADDITIVE", "L-7604", "FZ-2110", "FZ-2105", "67 ADDITIVE", "8618 ADDITIVE", "3 ADDITIVE", and "56 ADDITIVE").

<A-1-5. Fatty acid ester (D)>
As the fatty acid ester (D), any suitable fatty acid ester may be adopted as long as the effect of the present invention is not impaired. The effect of the present invention can be exhibited by including the fatty acid ester (D) in the pressure-sensitive adhesive composition. If the pressure-sensitive adhesive composition does not include the fatty acid ester (D), there is a risk that excellent easy peelability at the initial stage of attachment cannot be exhibited, or that an increase in peel strength over time cannot be suppressed.

The fatty acid ester (D) may be of only one type or of two or more types.

The content of the fatty acid ester (D) in the adhesive composition is preferably 0.01 to 50 parts by weight, more preferably 0.1 to 40 parts by weight, even more preferably 1 to 30 parts by weight, particularly preferably 5 to 20 parts by weight, and most preferably 7 to 15 parts by weight, per 100 parts by weight of the urethane prepolymer (A). If the content of the fatty acid ester (D) per 100 parts by weight of the urethane prepolymer (A) is within the above range, the effects of the present invention can be more effectively achieved. If the content of the fatty acid ester (D) per 100 parts by weight of the urethane prepolymer (A) is outside the above range, there is a risk that excellent easy peelability at the beginning of application cannot be achieved, or that an increase in peel strength over time cannot be suppressed.

As described below, when the adhesive composition contains an ionic compound (E), the content of the fatty acid ester (D) in the adhesive composition is preferably 0.01 to 28 parts by weight, more preferably 0.1 to 25 parts by weight, even more preferably 1 to 23 parts by weight, and particularly preferably 3 to 20 parts by weight, per 100 parts by weight of the urethane prepolymer (A). When the adhesive composition contains an ionic compound (E), the effect of the present invention can be more effectively achieved if the content of the fatty acid ester (D) per 100 parts by weight of the urethane prepolymer (A) is within the above range. When the adhesive composition contains an ionic compound (E), if the content of the fatty acid ester (D) per 100 parts by weight of the urethane prepolymer (A) is too large outside the above range, there is a risk of contamination of the adherend over time.

The number average molecular weight Mn of the fatty acid ester (D) is preferably 100 to 800, more preferably 150 to 700, even more preferably 200 to 600, even more preferably 250 to 500, particularly preferably 300 to 400, and most preferably 350 to 400. When the number average molecular weight Mn of the fatty acid ester (D) is within the above range, the effects of the present invention can be more effectively exhibited.

As the fatty acid ester, any suitable fatty acid ester may be used as long as it does not impair the effects of the present invention. Examples of such fatty acid esters include isotridecyl isononanoate, isopropyl palmitate, isopropyl myristate, polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, behenic acid monoglyceride, cetyl 2-ethylhexanoate, cholesteryl isostearate, lauryl methacrylate, coconut fatty acid methyl, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, isotridecyl stearate, 2-ethylhexanoic acid triglyceride, butyl laurate, and octyl oleate. Among these fatty acid esters, isotridecyl isononanoate, isopropyl palmitate, and isopropyl myristate are preferred, with isotridecyl isononanoate being more preferred, in that they can better exert the effects of the present invention. An example of a commercially available product of isotridecyl isononanoate is the product under the trade name "Salacos 913" (manufactured by Nisshin Oillio Group Co., Ltd.). An example of a commercially available product of isopropyl palmitate is the product under the trade name "Exepar IPP" (manufactured by Kao Corporation). An example of a commercially available product of isopropyl myristate is the product under the trade name "Exepar IPM" (manufactured by Kao Corporation).

<A-1-6. Ionic compound (E)>
The pressure-sensitive adhesive composition may contain an ionic compound (E). The ionic compound (E) can preferably exhibit an antistatic effect. It is presumed that by using the ionic compound (E) in combination with the fluorine-based compound (B), the ionic compound (E) is likely to be unevenly distributed on the surface side (the side to be bonded to the adherend) of the pressure-sensitive adhesive layer due to an interaction with the fluorine-based compound (B), and the surface protection film according to the embodiment of the present invention can more sufficiently suppress the peeling electrification voltage, exhibit better antistatic properties, and the pressure-sensitive adhesive layer can exhibit better anchoring properties.

The ionic compound (E) may be one type or two or more types.

The content of the ionic compound (E) in the adhesive composition is preferably 0.01 to 5.0 parts by weight, more preferably 0.05 to 3.0 parts by weight, even more preferably 0.1 to 2.0 parts by weight, particularly preferably 0.1 to 1.0 parts by weight, and most preferably 0.1 to 0.5 parts by weight, relative to 100 parts by weight of the urethane prepolymer (A). If the content of the ionic compound (E) relative to 100 parts by weight of the urethane prepolymer (A) is within the above range, the surface protection film according to the embodiment of the present invention can more sufficiently suppress the peeling charge voltage and exhibit more excellent antistatic properties. If the content of the ionic compound (E) relative to 100 parts by weight of the urethane prepolymer (A) is too low outside the above range, the peeling charge voltage cannot be sufficiently suppressed, and excellent antistatic properties may not be exhibited. If the content ratio of ionic compound (E) per 100 parts by weight of urethane prepolymer (A) is too high outside the above range, there is a risk of contamination of the adherend.

When the pressure-sensitive adhesive composition contains an ionic compound (E), the surface protection film according to an embodiment of the present invention has a peeling electrification voltage from an acrylic plate of preferably 5 kV or less, more preferably 4 kV or less, even more preferably 3 kV or less, and particularly preferably 2 kV or less.

As the ionic compound (E), any appropriate ionic compound may be used as long as it does not impair the effects of the present invention. Such an ionic compound (E) is preferably an ionic liquid. By ionic liquid, we mean a molten salt (ionic compound) that is liquid at 25°C.

As the ionic liquid, any appropriate ionic liquid may be used as long as it does not impair the effects of the present invention. As such an ionic liquid, an ionic liquid containing a fluoroorganic anion is preferable, and an ionic liquid composed of a fluoroorganic anion and an onium cation is more preferable, in terms of being able to further exert the effects of the present invention.

As the ionic liquid, in terms of being able to more effectively exhibit the effects of the present invention, 1-hexylpyridinium bis(fluorosulfonyl)imide, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium pentafluoroethanesulfonate, 1-ethyl-3-methylpyridinium heptafluoropropanesulfonate, 1-ethyl-3-methylpyridinium nonafluorobutanesulfonate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-octyl-4-methylpyridinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(trifluoromethane ... 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium heptafluoropropanesulfonate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-hexyl-3-methylimidazolium bis(fluorosulfonyl)imide, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, more preferably 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide.

Ionic liquids may be commercially available or synthesized. Methods for synthesizing ionic liquids include, for example, common synthesis methods using the halide method, hydroxide method, acid ester method, complex formation method, and neutralization method, as described in the literature "Ionic Liquids - The Frontline and Future of Development" (published by CMC Publishing Co., Ltd.).

<A-1-7. Other ingredients>
The adhesive composition may contain any other suitable components as long as they do not impair the effects of the present invention.Such other components include, for example, solvents, catalysts, crosslinking accelerators, silane coupling agents, antioxidants, ultraviolet absorbers, light stabilizers, resin components, tackifiers, crosslinking retarders, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), chain transfer agents, plasticizers, softeners, anti-aging agents, conductive agents, foil-like materials, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, and lubricants.Other components may be one type only, or two or more types.

<A-2. Base material layer>
The base material layer may be a single layer or may be two or more layers. The base material layer may be a stretched layer.

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

For the surface of the base layer on which the adhesive layer is not applied, a release treatment can be performed by adding, for example, fatty acid amide, polyethyleneimine, long-chain alkyl additives, etc. to the base layer in order to form a roll that is easy to unwind, or a coating layer made of any suitable release agent, such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent, can be provided.

As the material for the substrate layer, any appropriate material may be adopted depending on the application. Examples include plastic, paper, metal film, nonwoven fabric, etc. Plastic is preferable. That is, the substrate layer is preferably a plastic film. The substrate layer may be made of one type of material, or may be made of two or more types of materials. For example, it may be made of two or more types of plastic.

Examples of the above plastics include polyester resins, polyamide resins, and polyolefin resins. Examples of the polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

The substrate layer may contain any suitable additive as necessary. Examples of additives that may be contained in the substrate layer include antioxidants, UV absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, number, and amount of additives that may be contained in the substrate layer may be appropriately set depending on the purpose. In particular, when the substrate layer is made of plastic, it is preferable to contain some of the above additives for the purpose of preventing deterioration, etc. From the viewpoint of improving weather resistance, particularly preferred additives include antioxidants, UV absorbers, light stabilizers, and fillers.

<<B. Use>>
The surface protective film according to the embodiment of the present invention is typically a surface protective film including a pressure-sensitive adhesive layer that is attached to an exposed surface of an optical member or electronic member in order to prevent the surface of the optical member or electronic member from being scratched during processing, assembly, inspection, transportation, etc., in the manufacturing process of the optical member or electronic member, and can exhibit the effect of sufficiently suppressing peeling electrification voltage and not damaging the optical member or electronic member when peeled. Therefore, it can be suitably used for surface protection of optical members and electronic members. The optical member of the present invention is one to which the surface protective film of the present invention is attached. The electronic member of the present invention is one to which the surface protective film of the present invention is attached.

The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. The test and evaluation methods in the examples are as follows. Note that "parts" means "parts by weight" unless otherwise specified, and "%" means "% by weight" unless otherwise specified.

<Measurement of surface free energy of pressure-sensitive adhesive layer surface against diiodomethane>
The surface protection film from which the release liner had been removed was cut to a size of 50 mm wide x 100 mm long, and fixed to a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., model "CA-X") with the adhesive layer surface facing up, and 2.0 μL of water was dropped onto the adhesive layer surface to measure the contact angle. Next, 2.0 μL of diiodomethane was dropped in the same manner to measure the contact angle. From the contact angle values of the above two liquids, the surface free energy of the adhesive layer surface with respect to diiodomethane was calculated using the Owens-Wendt method.

<Peeling force P1 from acrylic plate (left at 23° C. for 30 minutes)>
The surface protection film from which the release liner had been peeled off was cut to a size of 25 mm wide x 140 mm long, and was attached to an acrylic plate (Acrylite, manufactured by Mitsubishi Chemical Corporation) by rolling it back and forth once with a 2 kg hand roller. Then, it was left at an environmental temperature of 23°C for 30 minutes. The obtained evaluation sample was measured with a tensile tester. As the tensile tester, a Shimadzu Corporation product name "Autograph AG-Xplus HS 6000 mm/min high-speed model (AG-50NX plus)" was used. After setting the evaluation sample in the tensile tester, the tensile test was started. The conditions of the tensile test were a peel angle of 180 degrees, and a peel speed (pulling speed): 300 mm/min. The load when the surface protection film was peeled off from the acrylic plate was measured, and the average load at that time was taken as the peel force P1 of the surface protection film against the acrylic plate.

<Peeling strength P2 from acrylic plate (left at 23°C for 1 week)>
The surface protection film from which the release liner had been peeled off was cut to a size of 25 mm wide x 140 mm long, and was attached to an acrylic plate (Acrylite, manufactured by Mitsubishi Chemical Corporation) by rolling it back and forth once with a 2 kg hand roller. After that, it was left for one week at an environmental temperature of 23 ° C. The obtained evaluation sample was measured with a tensile tester. As the tensile tester, a Shimadzu Corporation product name "Autograph AG-Xplus HS 6000 mm / min high-speed model (AG-50NX plus)" was used. After setting the evaluation sample in the tensile tester, the tensile test was started. The conditions of the tensile test were a peel angle of 180 degrees and a peel speed (pulling speed): 300 mm / min. The load when the surface protection film was peeled off from the acrylic plate was measured, and the average load at that time was taken as the peel force P2 of the surface protection film against the acrylic plate.

<Peeling strength P3 from acrylic plate (left at 50°C for 1 day)>
The surface protection film from which the release liner had been peeled off was cut to a size of 25 mm wide x 140 mm long, and was attached to an acrylic plate (Acrylite, manufactured by Mitsubishi Chemical Corporation) by rolling it back and forth once with a 2 kg hand roller. Then, it was left for one day at an environmental temperature of 50°C. The obtained evaluation sample was measured with a tensile tester. As the tensile tester, a Shimadzu Corporation product name "Autograph AG-Xplus HS 6000 mm/min high-speed model (AG-50NX plus)" was used. After setting the evaluation sample in the tensile tester, the tensile test was started. The conditions of the tensile test were a peel angle of 180 degrees, and a peel speed (pulling speed): 300 mm/min. The load when the surface protection film was peeled off from the acrylic plate was measured, and the average load at that time was taken as the peel force P3 of the surface protection film against the acrylic plate.

<Rate of increase in peel force over time from peel force P1 to peel force P2 (1)>
The rate of increase in the peel force with time (1) from the peel force P1 to the peel force P2 was calculated by the following formula.
Peel strength increase rate over time (1) (%) = (peel strength P2/peel strength P1) x 100 (%)

<Rate of increase in peel force over time from peel force P1 to peel force P3 (2)>
The rate of increase in the peel force with time (2) from the peel force P1 to the peel force P3 was calculated by the following formula.
Peel strength increase rate over time (2) (%) = (peel strength P3/peel strength P1) x 100 (%)

<Measurement of electrostatic potential against peeling of acrylic plate>
The surface protection film from which the release liner had been peeled off was cut to a size of 70 mm wide x 100 mm long, and was pressed against the surface of an acrylic plate (Acrylite, manufactured by Mitsubishi Chemical Corporation) as an adherend, with one end of the surface protection film protruding 30 mm from the end of the acrylic plate, by one round trip of a 2 kg hand roller. The obtained sample was left in an environment of 23 ° C. x 50% RH for one day, and then set at a predetermined position on a sample fixing table with a height of 20 mm. The end of the surface protection film protruding 30 mm from the acrylic plate was fixed to an automatic winding machine, and peeled off at a peel angle of 150 ° and a peel speed of 30 m / min. The electric potential of the adherend surface generated at this time was measured by a potential meter (manufactured by Shishido Electrostatic Co., Ltd., model "STATIRON DZ-4") fixed at a position 30 mm high from the center of the adherend, and was taken as the peeling electrification voltage against the acrylic plate. The measurement was performed in an environment of 23 ° C. and 50% RH.

<Black spot rating>
The release liner was peeled off from the surface protection film, and the number of black spots (glue dents) per 10 cm square (100 cm ² ) was visually confirmed.

<Contamination evaluation (left at 23°C for 1 week)>
The surface protection film from which the release liner had been removed was cut to a size of 50 mm wide x 100 mm long, and attached to an acrylic plate (Acrylite, manufactured by Mitsubishi Chemical Corporation) using a 2 kg hand roller in one reciprocating motion. The resulting sample was then left to stand for one week at an environmental temperature of 23° C. The surface protection film was peeled off from the obtained evaluation sample, and the adherend was visually inspected for any contamination.

<Contamination evaluation (left at 60°C and 90% humidity for 1 week or left at 50°C for 1 week)>
The surface protection film from which the release liner had been removed was cut to a size of 50 mm wide x 100 mm long, and attached to an acrylic plate (Acrylite, manufactured by Mitsubishi Chemical Corporation) with one round trip of a 2 kg hand roller. It was then left to stand for one week at a temperature of 60°C and a humidity of 90% (in the cases of Examples 1 to 16 and Comparative Examples 1 to 4) or at a temperature of 50°C (in the cases of Examples 17 to 34 and Comparative Examples 5 to 10). The surface protection film was peeled off from the obtained evaluation sample, and the adherend was visually inspected for contamination.

[Production Example 1]
Into a polymerization experimental apparatus equipped with a 1 L round-bottom separable flask, a separable cover, a separating funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade, 197 g of polypropylene glycol (product name "Sannyx PP-2000", manufactured by Sanyo Chemical Industries, Ltd.), 197 g of polyester polyol (product name "Kuraray Polyol P-2010", manufactured by Kuraray Co., Ltd.), 110 g of toluene (manufactured by Tosoh Corporation) as a solvent, and 0.041 g of dibutyltin(IV) dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst were charged, and nitrogen replacement was carried out at room temperature for 1 hour with stirring. Thereafter, under nitrogen flow, 33.5 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added while stirring, and the solution temperature in the experimental apparatus was controlled to 90 ± 2 ° C. in a water bath and held for 4 hours, after which 44 g of polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Industries, Ltd.) was added, and the solution temperature in the experimental apparatus was controlled to 90 ± 2 ° C. in a water bath and held for 2 hours, after which 25.4 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the solution temperature in the experimental apparatus was controlled to 90 ± 2 ° C. in a water bath and held for 2 hours to obtain a solution of urethane prepolymer (A). In addition, toluene was appropriately added dropwise during the polymerization to control the temperature during polymerization and prevent a decrease in stirrability due to an increase in viscosity. The total amount of toluene added was 380 g. The solids concentration of the solution of the urethane prepolymer (A) was 50% by weight.

[Example 1]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-354L (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (1). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 2]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-640 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (2). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 3]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.03 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (3). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 4]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (4). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 5]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.50 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (5). The film was aged at room temperature for 5 days and evaluated. The results are shown in Tables 1 and 2.

[Example 6]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 1.00 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (6). The film was aged at room temperature for 5 days and then evaluated. The results are shown in Tables 1 and 2.

[Example 7]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 3.00 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (7). The film was aged at room temperature for 5 days and then evaluated. The results are shown in Tables 1 and 2.

[Example 8]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 5.00 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (8). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 9]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-6002 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (9). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 10]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-6001 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (10). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 11]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of X-22-4272 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (11). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 12]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of isocyanate compound (Coronate HX:C/HX, Nippon Polyurethane Co., Ltd.) as crosslinking agent, 0.3 parts by weight of Megafac F-571 (DIC) as fluorine-based compound, 0.03 parts by weight of KF-615A (Shin-Etsu Chemical Co., Ltd.) as silicone-based compound, 10 parts by weight of Exepar IPP (Kao Corporation) as fatty acid ester, and 0.5 parts by weight of Irganox 1010 (BASF) as antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (trade name "T100-75S", thickness 75 μm, Mitsubishi Chemical Co., Ltd.) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (12). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 13]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of isocyanate compound (Coronate HX:C/HX, Nippon Polyurethane Co., Ltd.) as crosslinking agent, 0.3 parts by weight of Megafac F-571 (DIC) as fluorine-based compound, 0.03 parts by weight of KF-615A (Shin-Etsu Chemical Co., Ltd.) as silicone-based compound, 10 parts by weight of Exepar IPM (Kao Corporation) as fatty acid ester, and 0.5 parts by weight of Irganox 1010 (BASF Corporation) as antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (trade name "T100-75S", thickness 75 μm, Mitsubishi Chemical Co., Ltd.) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (13). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 14]
A urethane prepolymer (A) 100 parts by weight, an isocyanate compound (Coronate HX:C/HX, Nippon Polyurethane Co., Ltd.) 4.0 parts by weight as a crosslinking agent, Megafac F-571 (DIC Corporation) 0.3 parts by weight as a fluorine-based compound, KF-615A (Shin-Etsu Chemical Co., Ltd.) 0.03 parts by weight as a silicone-based compound, Salacos 913 (Nisshin Oillio Group Co., Ltd.) 5 parts by weight as a fatty acid ester, Irganox 1010 (BASF Corporation) 0.5 parts by weight as an antioxidant, and diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (trade name "T100-75S", thickness 75 μm, Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (14). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 15]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.03 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 15 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (15). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 16]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.03 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 30 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (16). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Comparative Example 1]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Co., Ltd.) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Co., Ltd.) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C1). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Comparative Example 2]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C2). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Comparative Example 3]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.3 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C3). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Comparative Example 4]
100 parts by weight of urethane prepolymer (A), 4.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 1.0 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.01 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C4). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 1 and 2.

[Example 17]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-354L (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (17). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 18]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-640 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (18). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 19]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.03 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (19). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 20]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (20). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 21]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.03 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of CIL-312 (manufactured by Nippon Carlit Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (21). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 22]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of CIL-312 (manufactured by Nippon Carlit Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (22). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 23]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.50 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (23). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 24]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 1.00 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (24). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 25]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 3.00 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (25). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 26]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 5.00 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (26). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 27]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-6002 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (27). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 28]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-6001 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (28). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 29]
100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of X-22-4272 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate so that the total solid content was 50% by weight, to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (29). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 30]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Industries, Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Exepar IPP (manufactured by Kao Corporation) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (30). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 31]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Industries, Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Exepar IPM (manufactured by Kao Corporation) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (31). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 32]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 5 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (32). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 33]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 15 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (33). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Example 34]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 30 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate so that the total solid content was 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (34). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Comparative Example 5]
100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Co., Ltd.) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Co., Ltd.) made of polyester resin so that the thickness after drying was 75 μm, and the coating was cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C5). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Comparative Example 6]
100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of isocyanate compound (Coronate HX:C/HX, Nippon Polyurethane Co., Ltd.) as crosslinking agent, 0.5 parts by weight of Megafac F-571 (DIC Corporation) as fluorine-based compound, 10 parts by weight of Salacos 913 (Nisshin Oillio Group Co., Ltd.) as fatty acid ester, 0.3 parts by weight of Elexcel AS110 (Dai-ichi Kogyo Seiyaku Co., Ltd.) as antistatic agent, and 0.5 parts by weight of Irganox 1010 (BASF Corporation) as antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C6). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Comparative Example 7]
100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of isocyanate compound (Coronate HX:C/HX, Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (DIC) as a fluorine-based compound, 0.10 parts by weight of KF-615A (Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 0.3 parts by weight of Elexel AS110 (Dai-Ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (BASF) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (trade name "T100-75S", thickness 75 μm, Mitsubishi Chemical Co., Ltd.) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C7). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Comparative Example 8]
100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C8). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Comparative Example 9]
A urethane-based adhesive composition was obtained by diluting 100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 1.0 part by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.01 part by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 10 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group, Ltd.) as a fatty acid ester, 0.3 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant with ethyl acetate to a total solid content of 50% by weight. The obtained urethane-based adhesive composition was applied to a substrate made of polyester resin (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and cured and dried under conditions of a drying temperature of 130° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner made of polyester resin having a thickness of 25 μm and one side of which was silicone-treated (product name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) was laminated to the surface of the obtained adhesive layer to obtain a surface protection film (C9). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Comparative Example 10]
100 parts by weight of urethane prepolymer (A), 3.0 parts by weight of an isocyanate compound (Coronate HX:C/HX, manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent, 0.5 parts by weight of Megafac F-571 (manufactured by DIC Corporation) as a fluorine-based compound, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 30 parts by weight of Salacos 913 (manufactured by Nisshin Oillio Group Co., Ltd.) as a fatty acid ester, and 0.5 parts by weight of Irganox 1010 (manufactured by BASF Corporation) as an antioxidant were diluted with ethyl acetate to a total solid content of 50% by weight to obtain a urethane-based adhesive composition. The obtained urethane-based adhesive composition was applied to a substrate (product name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) made of polyester resin so that the thickness after drying was 75 μm, and the mixture was cured and dried under conditions of a drying temperature of 130 ° C. and a drying time of 3 minutes to prepare an adhesive layer. Next, the silicone-treated surface of a release liner (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a polyester resin having a thickness of 25 μm and having one side treated with silicone was laminated to the surface of the obtained pressure-sensitive adhesive layer to obtain a surface protection film (C10). Aging was performed at room temperature for 5 days, and evaluation was performed. The results are shown in Tables 3 and 4.

[Examples 35 to 68]
For each of the surface protection films (1) to (34) obtained in Examples 1 to 34, the release liner was peeled off, and the pressure-sensitive adhesive layer side was attached to a polarizing plate (manufactured by Nitto Denko Corporation, product name "TEG1465DUHC"), which is an optical component, to obtain an optical component with a surface protection film attached thereto.

[Examples 69 to 102]
For each of the surface protection films (1) to (34) obtained in Examples 1 to 34, the release liner was peeled off, and the pressure-sensitive adhesive layer side was attached to a conductive film (manufactured by Nitto Denko Corporation, product name "ELECRYSTA V270L-TFMP"), which is an electronic component, to obtain an electronic component having a surface protection film attached thereto.

The surface protection film of the present invention can be used for any suitable application. Preferably, the surface protection film of the present invention is used in the fields of optical components and electronic components.

1 Base layer 2 Pressure-sensitive adhesive layer 10 Surface protection film

Claims (11)

A surface protection film including a pressure-sensitive adhesive layer,
the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition,
the pressure-sensitive adhesive composition comprises a urethane prepolymer (A), a fluorine-based compound (B), a silicone-based compound (C), and a fatty acid ester (D);
the surface free energy of the pressure-sensitive adhesive layer with respect to diiodomethane is 0.1 mJ/m ² to 8.0 mJ/m ² ;
Surface protection film. The surface protection film according to claim 1, wherein the content of the silicone compound (C) is 0.02 to 3 parts by weight per 100 parts by weight of the urethane prepolymer (A). The surface protective film according to claim 1, wherein the peel force P1 is the peel force when the adhesive layer contained in the surface protective film is attached to the surface of an acrylic plate and left at a temperature of 23°C for 30 minutes, and then the surface protective film is peeled from the surface of the acrylic plate at a peel angle of 180 degrees and a peel speed of 300 mm/min at a temperature of 23°C, and the peel force P2 is the peel force when the adhesive layer contained in the surface protective film is attached to the surface of an acrylic plate and left at a temperature of 23°C for one week, and then the surface protective film is peeled from the surface of the acrylic plate at a peel angle of 180 degrees and a peel speed of 300 mm/min at a temperature of 23°C. The ... temperature of 23°C. The peel force P2 is the peel force when the surface protective film is peeled from the surface of the acrylic plate at a peel angle of 180 degrees and a peel speed of 300 mm/min at a temperature of 23°C. The peel force P2 is the peel force when the adhesive layer contained in the surface protective film is peeled from the surface of the acrylic plate at a peel angle of 180 degrees and a peel speed of 300 mm/min at a temperature of 23°C. The surface protective film according to claim 1, wherein the peel force P1 is the peel force when the adhesive layer contained in the surface protective film is attached to the surface of an acrylic plate and left at a temperature of 23°C for 30 minutes, and then the surface protective film is peeled from the surface of the acrylic plate at a peel angle of 180° and a peel speed of 300 mm/min at a temperature of 23°C, and the peel force P3 is the peel force when the adhesive layer contained in the surface protective film is attached to the surface of an acrylic plate and left at a temperature of 50°C for 1 day, and then the surface protective film is peeled from the surface of the acrylic plate at a peel angle of 180° and a peel speed of 300 mm/min at a temperature of 23°C. The ... peeled from the surface of the acrylic plate at a peel angle of 100° and a peel speed of 300 mm/min at a temperature of 23°C. The surface protective film according to claim 1 , wherein the number of black spots generated in the pressure-sensitive adhesive layer contained in the surface protective film is 5 or less per 100 cm ² . The surface protective film according to claim 1, wherein the pressure-sensitive adhesive composition contains an ionic compound (E). The surface protective film according to claim 6, wherein the molecular weight of the ionic compound (E) is 350 or less. The surface protection film according to claim 6, which has a peeling charge voltage against an acrylic plate of 2 kV or less. The surface protection film according to claim 6, wherein the content of the fatty acid ester (D) is 0.01 to 28 parts by weight per 100 parts by weight of the urethane prepolymer (A). An optical member to which the surface protective film according to any one of claims 1 to 9 is attached. An electronic component to which the surface protection film according to any one of claims 1 to 9 is attached.

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