Surface protection film

Abstract

Provided is a surface protection film that includes an adhesive agent layer, and that is capable of achieving both excellent antistatic performance and suppression of tainting of an adherend.　A surface protection film according to one embodiment of the present invention includes an adhesive agent layer comprising a urethane-based adhesive agent. The urethane-based adhesive agent contains a urethane polymer. The urethane-based adhesive agent is formed from a urethane-based adhesive agent composition. The urethane-based adhesive agent composition contains a base polymer (A), a silicone-based compound (B), and an ionic compound (C). The surface protection film has a counter glass sheet surface resistance value of 5.0×1010Ω or more.

Description

Surface protection film

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

[0002] In the manufacturing process of optical or electronic components, a surface protection film is generally attached 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 required (Patent Document 1).

[0003] Surface protection films, optical components, and electronic components have high electrical insulation properties and generate static electricity due to friction or peeling. Therefore, static electricity is likely to be generated when peeling a surface protection film from an optical component or electronic component to which the surface protection film is attached. For example, if a voltage is applied to a liquid crystal panel while this static electricity remains, the orientation of the liquid crystal molecules may be lost or the panel may be damaged. Furthermore, the presence of static electricity may attract dust or reduce workability.

[0004] In order to prevent the generation of static electricity as described above, techniques for subjecting surface protection films to antistatic treatment have been reported, such as a technique in which an ionic compound such as an alkali metal salt or an ionic liquid that functions as an antistatic agent is contained in a pressure-sensitive adhesive layer of the surface protection film (Patent Document 2).

[0005] However, when an antistatic agent is contained in the pressure-sensitive adhesive layer, the adherend may be contaminated by the antistatic agent, which may result in a process defect such as peeling of another member from the adherend when the surface protection film attached to the adherend is peeled off from the adherend and another member is then attached to the peeled surface of the adherend.

[0006] Patent No. 6613516 Patent No. 6896927

[0007] An object of the present invention is to provide a surface protection film including a pressure-sensitive adhesive layer, which can simultaneously exhibit excellent antistatic properties and inhibit contamination of an adherend.

[0008] [1] A surface protection film according to an embodiment of the present invention is a surface protection film including a pressure-sensitive adhesive layer composed of a urethane-based pressure-sensitive adhesive, wherein the urethane-based pressure-sensitive adhesive includes a urethane polymer, and the urethane-based pressure-sensitive adhesive is formed from a urethane-based pressure-sensitive adhesive composition, and the urethane-based pressure-sensitive adhesive composition includes a base polymer (A), a silicone-based compound (B), and an ionic compound (C). The surface protection film is attached to a glass plate in an environment of a temperature of 23°C and a humidity of 50% RH, and left for 4 hours. After the surface protection film is peeled from the glass plate, a voltage of 250 V is applied to the center of the peeled surface of the glass plate for 10 seconds, and the surface resistance value is 5.0 × 10 10Ω or more. [2] In the surface protective film according to [1] above, the fluorine content in the pressure-sensitive adhesive layer may be 0.20 wt % or less. [3] In the surface protective film according to [1] or [2] above, the urethane polymer may be a prepolymer-type urethane polymer, and the pressure-sensitive adhesive layer may be attached to a glass plate, left for 30 minutes at an ambient temperature of 23° C., and then the surface protective film may be peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min, where the average peel strength is defined as adhesive strength (I), and the average peel strength is defined as adhesive strength (II) when the pressure-sensitive adhesive layer is attached to a glass plate, left for 1 day at an ambient temperature of 50° C., and then the surface protective film is peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min, and the rate of increase over time in adhesive strength to the glass plate, defined as [adhesive strength (II) / adhesive strength (I)]×100(%), may be less than 210%. [4] In the surface protective film according to the above [1] or [2], the urethane polymer may be a one-shot urethane polymer, and the adhesive layer may be attached to a glass plate, left for 30 minutes at an ambient temperature of 23°C, and then peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min, where the average peel strength is defined as adhesive strength (I), and the adhesive layer may be attached to a glass plate, left for 1 day at an ambient temperature of 50°C, and then peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min, where the average peel strength is defined as adhesive strength (II), and the average peel strength is defined as adhesive strength (II) / adhesive strength (I) × 100 (%), where the increase in adhesive strength to the glass plate over time is less than 160%. [5] In the surface protective film according to any of the above [1] to [4], the content of the ionic compound (C) per 100 parts by weight of the base polymer (A) may be 0.01 to 2.8 parts by weight. [6] In the surface protective film according to any one of the above [1] to [5], the silicone-based compound (B) may contain a silicone-based compound having a polyether structure.[7] In the surface protective film according to [6] above, the silicone compound having a polyether structure may be at least one selected from the group consisting of reactive silicone oils and non-reactive silicone oils having an HLB value of 15 or less. [8] An optical member according to an embodiment of the present invention includes the surface protective film according to any one of [1] to [7] above. [9] An electronic member according to an embodiment of the present invention includes the surface protective film according to any one of [1] to [7] above.

[0009] According to the present invention, it is possible to provide a surface protection film including a pressure-sensitive adhesive layer, which can simultaneously exhibit excellent antistatic properties and inhibit contamination of an adherend.

[0010] 1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention.

[0011] When the expression "weight" appears in this specification, it may be read as "mass," which is commonly used as an SI unit indicating weight.

[0012] 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".

[0013] A. Surface Protection Film The surface protection film according to the embodiment of the present invention includes a pressure-sensitive adhesive layer made of a urethane-based pressure-sensitive adhesive. In the surface protection film according to the embodiment of the present invention, the urethane-based pressure-sensitive adhesive includes a urethane polymer.

[0014] In the surface protection film according to an embodiment of the present invention, the urethane-based adhesive is formed from a urethane-based adhesive composition, which contains a base polymer (A), a silicone-based compound (B), and an ionic compound (C).

[0015] In the surface protection film according to an embodiment of the present invention, the total content of the base polymer (A), the silicone compound (B), and the ionic compound (C) in the urethane-based pressure-sensitive adhesive composition is, in terms of solid content, preferably 50% by weight to 100% by weight, more preferably 70% by weight to 99% by weight, even more preferably 80% by weight to 98% by weight, and particularly preferably 90% by weight to 97% by weight.

[0016] In the surface protection film according to the embodiment of the present invention, the content of the base polymer (A) in the urethane-based pressure-sensitive adhesive composition is preferably 60% by weight to 99.9% by weight, more preferably 70% by weight to 99% by weight, even more preferably 80% by weight to 98% by weight, and particularly preferably 90% by weight to 97% by weight, calculated as solids. When the content of the base polymer (A) in the urethane-based pressure-sensitive adhesive composition is within the above range, the effects of the present invention can be more effectively exhibited.

[0017] The surface protection film according to an embodiment of the present invention may include any other appropriate components as long as the effects of the present invention are not impaired, as long as the surface protection film according to an embodiment of the present invention includes a substrate and the above-mentioned pressure-sensitive adhesive layer. Furthermore, as described below, the surface of the pressure-sensitive adhesive layer opposite the substrate may be provided with any appropriate release liner (sometimes referred to as a release sheet or separator) for protection until use, etc.

[0018] Fig. 1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention. In Fig. 1, a surface protection film 10 includes a substrate 1 and a pressure-sensitive adhesive layer 2. In Fig. 1, the substrate 1 and the pressure-sensitive adhesive layer 2 are directly laminated together.

[0019] In Figure 1, any appropriate release liner (sometimes referred to as a release sheet or separator) may be provided (not shown) on the surface of the pressure-sensitive adhesive layer 2 opposite the substrate 1 for protection until use, etc. Examples of release liners include release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is treated with silicone, and release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin.

[0020] Examples of plastic films usable 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.

[0021] 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.

[0022] The thickness of the surface protection film according to the embodiment of the present invention may be any appropriate thickness as long as the effects of the present invention are not impaired. Such a thickness 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.

[0023] The surface protection film according to the embodiment of the present invention is preferably adhered to a glass plate in an environment of a temperature of 23° C. and a humidity of 50% RH, and then the surface protection film is peeled off from the glass plate. After that, a voltage of 250 V is applied to the center of the peeled surface of the glass plate for 10 seconds, and the surface resistance (surface resistance to the glass plate) is preferably 5.0×10 10 Ω or more, more preferably 1.0 × 10 11 Ω or more, and particularly preferably 5.0 × 1011 Ω or more, and most preferably 1.0×10 12 Ω or more. The higher the surface resistance, the better, and there is no upper limit. The measurable upper limit may be the upper limit of the measurement limit of the measuring device, so for example, the surface resistance may exceed the measurement limit of the measuring device. As described above, the surface protective film according to an embodiment of the present invention includes a pressure-sensitive adhesive layer composed of a urethane-based pressure-sensitive adhesive formed from a urethane-based pressure-sensitive adhesive composition containing a urethane polymer (A), a silicone-based compound (B), and an ionic compound (C), and by adjusting the surface resistance to glass plate within the above range, a surface protective film can be provided that can simultaneously exhibit excellent antistatic performance and inhibit contamination of the adherend. If the surface resistance to glass plate is too small outside the above range, for example, there is a risk that excellent antistatic performance and inhibit contamination of the adherend cannot simultaneously be exhibited. Thus, the present inventors have found that, in a surface protection film including a pressure-sensitive adhesive layer, by adopting a pressure-sensitive adhesive layer composed of a urethane-based pressure-sensitive adhesive formed from a urethane-based pressure-sensitive adhesive composition containing a urethane polymer (A), a silicone compound (B), and an ionic compound (C) as described above, and by adjusting the surface resistance value to glass plate within the above range, an unexpected effect can be achieved, as described above, that is, excellent antistatic performance and prevention of contamination of the adherend can be simultaneously achieved. Note that the details of the method for measuring the surface resistance value to glass plate will be described later.

[0024] The surface protective film according to an embodiment of the present invention preferably exhibits a peeling electrification voltage (peel electrification voltage from glass plate) of 7.5 kV or less, more preferably 0 kV to 6.5 kV, even more preferably 0 kV to 5.5 kV, even more preferably 0 kV to 4.5 kV, even more preferably 0 kV to 3.5 kV, even more preferably 0 kV to 3.0 kV, even more preferably 0 kV to 2.5 kV, particularly preferably 0 kV to 2.0 kV, and most preferably 0 kV to 1.5 kV, when the surface protective film is attached to a glass plate and left for one day in an environment of 23°C and 50% RH, and then peeled from the glass plate at a peel angle of 150° and a peel speed of 15 m / min. If the glass plate peeling electrification voltage is within the above range, a surface protective film having excellent antistatic properties can be provided. If the glass peeling electrostatic voltage is too large and outside the above range, static electricity may be easily generated, for example, when the surface protective film is peeled off from an optical member or electronic member to which the surface protective film is attached. The method for measuring the glass peeling electrostatic voltage will be described in detail later.

[0025] In the surface protective film according to an embodiment of the present invention, when the surface protective film is attached to a glass plate and left for 30 minutes at an ambient temperature of 23°C, and then the surface protective film is peeled off from the glass plate, the amount of elemental sulfur transferred to the peeled surface of the glass plate is preferably 3.5 atomic% or less, more preferably 0 atomic% to 3.0 atomic%, even more preferably 0 atomic% to 2.5 atomic%, still more preferably 0 atomic% to 2.0 atomic%, still more preferably 0 atomic% to 1.5 atomic%, still more preferably 0 atomic% to 1.0 atomic%, particularly preferably 0 atomic% to 0.5 atomic%, and most preferably 0 atomic% to 0.1 atomic%. The sulfur element transfer amount is an index of the degree of contamination of an adherend, and the smaller the value, the less contamination there is on the peeled surface of the adherend when the surface protection film is attached to the adherend and then peeled off. If the sulfur element transfer amount is within the above range, a surface protection film that can suppress contamination of the adherend can be provided. If the sulfur element transfer amount is too large outside the above range, for example, the degree of contamination of the adherend may increase. Note that details of the method for measuring the sulfur element transfer amount will be described later.

[0026] In the surface protection film according to an embodiment of the present invention, the fluorine content in the pressure-sensitive adhesive layer is preferably 0.20 wt % or less, more preferably 0 wt % to 0.15 wt %, even more preferably 0 wt % to 0.10 wt %, particularly preferably 0 wt % to 0.07 wt %, and most preferably 0 wt % to 0.05 wt %. By adjusting the fluorine content in the pressure-sensitive adhesive layer within the above range, even if the surface protection film attached to an adherend is peeled from the adherend and then another component is attached to the release surface of the adherend and exposed to high temperature conditions, peeling of the component from the adherend can be sufficiently suppressed. If the fluorine content in the pressure-sensitive adhesive layer is too high outside the above range, for example, when the surface protection film attached to an adherend is peeled from the adherend and then another component is attached to the release surface of the adherend and exposed to high temperature conditions, the component may be more likely to peel from the adherend. Details of the method for measuring the fluorine content in the pressure-sensitive adhesive layer will be described later.

[0027] In the surface protection film according to an embodiment of the present invention, the adhesive layer is attached to a glass plate, left for 30 minutes at an ambient temperature of 23°C, and then peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min. The adhesive strength (I), which is the average peel strength when the surface protection film is peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min, is preferably 5.0 gf / 25 mm or less, more preferably 4.0 gf / 25 mm or less, even more preferably 3.5 gf / 25 mm or less, and particularly preferably 3.0 gf / 25 mm or less. From the viewpoint of ensuring proper function as a surface protection film, the lower limit of the adhesive strength (I) is preferably 0.3 gf / 25 mm or more in practice. If the adhesive strength (I) is within the above range, a surface protection film that adheres appropriately to an adherend and is easy to peel can be provided. If the adhesive strength (I) is too large outside the above range, for example, the surface protection film may have too high adhesion to an adherend, making it difficult to peel. Details of the method for measuring the adhesive strength (I) will be described later.

[0028] In the surface protection film according to an embodiment of the present invention, when the adhesive layer is attached to a glass plate, left at an ambient temperature of 50° C. for one day, and then the surface protection film is peeled from the glass plate at a peel angle of 180° and a peel rate of 300 mm / min, the average peel strength is defined as adhesive strength (II), which is the degree of increase in adhesive strength from the adhesive strength (I), i.e., the rate of increase in adhesive strength to the glass plate over time, defined as [adhesive strength (II) / adhesive strength (I)]×100(%), is preferably less than 210%, more preferably 200% or less, even more preferably 190% or less, even more preferably 180% or less, even more preferably 170% or less, even more preferably 160% or less, particularly preferably 150% or less, and most preferably 140% or less. The lower limit of the rate of increase in adhesive strength to the glass plate over time is preferably 100% or more. If the rate of increase in adhesive strength to glass plate over time is within the above range, the increase in adhesive strength to the adherend over time is suppressed, and a surface protection film can be provided that maintains adequate adhesion to the adherend even after a long time has passed after being attached to the adherend and is easy to peel off. If the rate of increase in adhesive strength to glass plate over time is too large outside the above range, for example, the adhesive strength to the adherend may increase over time, and over time after being attached to the adherend, the film may adhere strongly and become difficult to peel off. Details of the method for measuring the adhesive strength (II) will be described later.

[0029] When the urethane polymer contained in the urethane-based adhesive that constitutes the adhesive layer is a prepolymer-type urethane polymer, the rate of increase over time in the adhesive strength to the glass plate is preferably less than 210%, more preferably 180% or less, even more preferably 170% or less, even more preferably 160% or less, even more preferably 150% or less, even more preferably 140% or less, particularly preferably 135% or less, and most preferably 130% or less. The lower limit of the rate of increase over time in the adhesive strength to the glass plate is preferably 100% or more.

[0030] When the urethane polymer contained in the urethane-based adhesive that constitutes the adhesive layer is a one-shot type urethane polymer, the rate of increase over time of the adhesive strength to the glass plate is preferably less than 210%, more preferably 180% or less, even more preferably 160% or less, even more preferably 150% or less, even more preferably 140% or less, even more preferably 130% or less, particularly preferably 125% or less, and most preferably 120% or less. The lower limit of the rate of increase over time of the adhesive strength to the glass plate is preferably 100% or more.

[0031] The surface protective film according to an embodiment of the present invention has an adhesive layer attached to a glass plate, left at an ambient temperature of 23°C for one day, and then peeled from the glass plate. No. 31B adhesive tape (manufactured by Nitto Denko Corporation) is applied to the release surface of the glass plate, and the tape is then peeled off at 85°C at a peel angle of 180° and a peel rate of 10 mm / min. The No. 31B high-temperature low-speed adhesive strength to glass plate is preferably 1.0 gf / 25 mm or more, more preferably 1.5 gf / 25 mm or more, even more preferably 2.0 gf / 25 mm or more, particularly preferably 2.5 gf / 25 mm or more, and most preferably 3.0 gf / 25 mm or more. The lower the contamination of the glass plate after peeling the surface protective film from the glass plate, the higher the No. 31B high-temperature low-speed adhesive strength to glass plate. This indicates that the No. 31B adhesive tape (manufactured by Nitto Denko Corporation) adheres firmly, so the higher the No. 31B high-temperature, low-speed adhesive strength to glass plates, the better, and there is no upper limit. If the No. 31B high-temperature, low-speed adhesive strength to glass plates is within the above range, even if a surface protective film attached to an adherend is peeled from the adherend and then another member is attached to the peeled surface of the adherend and exposed to high temperatures, peeling of the member from the adherend can be sufficiently suppressed. If the No. 31B high-temperature, low-speed adhesive strength to glass plates is too small, for example, when a surface protective film attached to an adherend is peeled from the adherend and then another member is attached to the peeled surface of the adherend and exposed to high temperatures, peeling of the member from the adherend may occur more easily. Details of the method for measuring the No. 31B high-temperature, low-speed adhesive strength to glass plates will be described later.

[0032] The surface protection film according to an embodiment of the present invention preferably has a haze of 5.0% or less, more preferably 4.0% or less, even more preferably 3.0% or less, particularly preferably 2.0% or less, and most preferably 1.0% or less. The lower limit of the haze is preferably 0% or more. If the haze is within the above range, the transparency of the surface protection film is high, and, for example, accurate inspections can be performed after the surface protection film is attached to the surface of an adherend such as an optical component or an electronic component. If the haze is too large outside the above range, for example, the transparency of the surface protection film may decrease, which may hinder the above-mentioned inspections. The method for measuring the haze will be described in detail below.

[0033] The surface protection film according to an embodiment of the present invention can be manufactured by any suitable method. Examples of such manufacturing methods include: (1) a method of applying a solution or a hot-melt liquid of a material for forming a pressure-sensitive adhesive layer onto a substrate; (2) a method of applying a solution or a hot-melt liquid of a material for forming a pressure-sensitive adhesive layer onto a release liner to form a pressure-sensitive adhesive layer, and then transferring the resulting layer onto a substrate; (3) a method of extruding a material for forming a pressure-sensitive adhesive layer onto a substrate to form a coating; (4) a method of extruding a substrate and a pressure-sensitive adhesive layer in a two-layer or multi-layer configuration; (5) a method of laminating a single-layer pressure-sensitive adhesive layer onto a substrate, or a method of laminating a two-layer pressure-sensitive adhesive layer together with a laminate layer; and (6) a method of laminating a pressure-sensitive adhesive layer with a substrate-forming material such as a film or a laminate layer in a two-layer or multi-layer configuration. Any suitable method can be used as the above-mentioned coating method. Examples of the coating method that can be used include roll coater method, comma coater method, die coater method, reverse coater method, silk screen method, and gravure coater method.

[0034] <A-1. Pressure-sensitive adhesive layer> The pressure-sensitive adhesive layer is composed of a urethane-based pressure-sensitive adhesive. The urethane-based pressure-sensitive adhesive is formed from a urethane-based pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer is composed of a urethane-based pressure-sensitive adhesive, and the urethane-based pressure-sensitive adhesive is formed from a urethane-based pressure-sensitive adhesive composition. Typically, the urethane-based pressure-sensitive adhesive formed from the urethane-based pressure-sensitive adhesive composition forms a layer shape to become the pressure-sensitive adhesive layer.

[0035] The pressure-sensitive adhesive layer can be formed by any appropriate method. For example, a method can be mentioned in which a urethane-based pressure-sensitive adhesive composition is applied to any appropriate substrate, heated and dried as necessary, and cured as necessary to form a pressure-sensitive adhesive layer on the substrate. The application method, heating and drying conditions, curing conditions, etc. can be appropriately selected from methods commonly known for forming pressure-sensitive adhesive layers.

[0036] The thickness of the pressure-sensitive adhesive layer can be appropriately set depending on the purpose of the present invention, as long as the effects of the present invention are not impaired. The thickness of the pressure-sensitive adhesive layer is typically 5 μm to 150 μm.

[0037] When the urethane polymer contained in the urethane-based adhesive is a prepolymer-type urethane polymer described below, the thickness of the pressure-sensitive adhesive layer is typically 5 μm to 150 μm, preferably 10 μm to 120 μm, more preferably 20 μm to 110 μm, even more preferably 30 μm to 100 μm, and particularly preferably 40 μm to 90 μm.

[0038] When the urethane polymer contained in the urethane-based adhesive is a one-shot urethane polymer described below, the thickness of the pressure-sensitive adhesive layer is typically 5 μm to 150 μm, preferably 7 μm to 100 μm, more preferably 10 μm to 50 μm, even more preferably 13 μm to 40 μm, and particularly preferably 15 μm to 30 μm.

[0039] In the surface protection film according to the embodiment of the present invention, the urethane-based pressure-sensitive adhesive contains a urethane polymer. The urethane polymer in the urethane-based pressure-sensitive adhesive may be of one type or two or more types.

[0040] In the surface protection film according to the embodiment of the present invention, the content of the urethane polymer in the urethane-based pressure-sensitive adhesive is preferably 60% by weight to 99.9% by weight, more preferably 70% by weight to 99.9% by weight, even more preferably 80% by weight to 99.9% by weight, particularly preferably 85% by weight to 99.9% by weight, and most preferably 90% by weight to 99.9% by weight. When the content of the urethane polymer in the urethane-based pressure-sensitive adhesive is within the above range, calculated as solid content, the effects of the present invention can be more effectively exhibited.

[0041] Known urethane polymers are generally classified into "prepolymer-type urethane polymers" produced by reacting a urethane prepolymer with a polyfunctional isocyanate compound, and "one-shot-type urethane polymers" produced by directly reacting a polyol with a polyfunctional isocyanate compound without using a urethane prepolymer. Urethane prepolymers are typically obtained by reacting a polyol with an excess of a polyfunctional isocyanate compound, and have isocyanate groups at the molecular terminals.

[0042] Therefore, in the surface protection film according to the embodiment of the present invention, the urethane polymer contained in the urethane-based pressure-sensitive adhesive is typically at least one selected from the group consisting of prepolymer-type urethane polymers and one-shot-type urethane polymers. The prepolymer-type urethane polymer may be of only one type, or may be of two or more types. The one-shot-type urethane polymer may be of only one type, or may be of two or more types.

[0043] Here, the prepolymer-type urethane polymer is obtained by reacting a urethane prepolymer as the base polymer (A) contained in the urethane-based pressure-sensitive adhesive composition with a polyfunctional isocyanate compound. Therefore, when the urethane polymer is a prepolymer-type urethane polymer, the urethane-based pressure-sensitive adhesive composition that forms the urethane-based pressure-sensitive adhesive typically contains a urethane prepolymer as the base polymer (A), a polyfunctional isocyanate compound, a silicone-based compound (B), and an ionic compound (C). The prepolymer-type urethane polymer can be prepared by any appropriate method that is used in the urethane reaction between the urethane prepolymer as the base polymer (A) and the polyfunctional isocyanate compound, as long as the effects of the present invention are not impaired.

[0044] Similarly, a one-shot urethane polymer is obtained by reacting a polyol (not a urethane prepolymer) as the base polymer (A) contained in a urethane-based pressure-sensitive adhesive composition with a polyfunctional isocyanate compound. Therefore, when the urethane polymer is a one-shot urethane polymer, the urethane-based pressure-sensitive adhesive composition that forms the urethane-based pressure-sensitive adhesive typically contains a polyol (not a urethane prepolymer) as the base polymer (A), a polyfunctional isocyanate compound, a silicone-based compound (B), and an ionic compound (C). The one-shot urethane polymer can be prepared by any appropriate method that is used in the urethane reaction between a polyol as the base polymer (A) and a polyfunctional isocyanate compound, as long as the effects of the present invention are not impaired.

[0045] <A-1-1. Urethane Prepolymer as Base Polymer (A)> The urethane prepolymer as the base polymer (A) can react with a polyfunctional isocyanate compound to form a prepolymer-type urethane polymer.

[0046] The urethane prepolymer may be of one type only, or of two or more types.

[0047] The urethane prepolymer is preferably a polyurethane polyol, more preferably obtained by reacting a polyol with a polyfunctional isocyanate compound. The number average molecular weight Mn of the urethane prepolymer is, for example, 3,000 to 1,000,000.

[0048] The polyol includes at least one selected from the group consisting of polyester polyols and polyether polyols. Typically, the polyol is at least one selected from the group consisting of polyester polyols and polyether polyols. The polyester polyol may be of only one type, or may be of two or more types. The polyether polyol may be of only one type, or may be of two or more types.

[0049] As the polyester polyol, polyester polyols that can be commonly used in preparing urethane prepolymers can be appropriately used. Examples of such polyester polyols include polyester polyols obtained by reacting an acid component with a glycol component. Examples of the acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, and pentaerythritol. In addition to these, examples of polyester polyols include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0050] The molecular weight of the polyester polyol may range from low to high, and the number average molecular weight Mn of the polyester polyol is, for example, 100 to 100,000, and preferably 100 to 10,000.

[0051] As the polyether polyol, polyether polyols that can be normally used in preparing urethane prepolymers can be appropriately adopted.Such polyether polyols include polyether polyols that contain two or more functional groups, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc., and typically include polyether polyols that contain two or more of at least one group selected from the group consisting of methylene groups and methine groups.If necessary, polyether polyols can be partially replaced with glycols such as ethylene glycol, polyamines such as ethylenediamine, etc.

[0052] The molecular weight of the polyether polyol may range from low to high, and the number average molecular weight Mn of the polyether polyol is, for example, 100 to 100,000, and preferably 100 to 10,000.

[0053] One embodiment of the polyol is embodiment (A) which includes both a polyester polyol and a polyether polyol. In embodiment (A), typically the polyol comprises both a polyester polyol and a polyether polyol.

[0054] In embodiment (A), the content of the polyester polyol in the polyol is preferably 0.1% by weight to 99.9% by weight, more preferably 0.1% by weight to 80% by weight, even more preferably 0.2% by weight to 60% by weight, still more preferably 0.2% by weight to 40% by weight, particularly preferably 0.3% by weight to 30% by weight, and most preferably 0.3% by weight to 20% by weight.

[0055] In embodiment (A), the content of the polyether polyol in the polyol is preferably 0.1% by weight to 99.9% by weight, more preferably 20% by weight to 99.9% by weight, even more preferably 40% by weight to 99.8% by weight, still more preferably 60% by weight to 99.8% by weight, particularly preferably 70% by weight to 99.7% by weight, and most preferably 80% by weight to 99.7% by weight.

[0056] In embodiment (A), the polyether polyol is typically a polyether polyol containing two or more of at least one group selected from the group consisting of methylene groups and methine groups. For example, it may be only a polyether polyol containing two of at least one group selected from the group consisting of methylene groups and methine groups, or it may be composed of a polyether polyol containing two of at least one group selected from the group consisting of methylene groups and methine groups and a polyether polyol containing three or more of at least one group selected from the group consisting of methylene groups and methine groups. Examples of polyether polyols containing two of at least one group selected from the group consisting of methylene groups and methine groups include polyethylene glycol and polypropylene glycol. Examples of polyether polyols containing three or more of at least one group selected from the group consisting of methylene groups and methine groups include polytetramethylene glycol.

[0057] Another embodiment of the polyol is embodiment (B) which does not include a polyester polyol but includes a polyether polyol. In embodiment (B), the polyol typically consists of a polyether polyol.

[0058] In embodiment (B), the polyether polyol is typically a polyether polyol containing two or more of at least one group selected from the group consisting of methylene groups and methine groups. For example, it may be only a polyether polyol containing two of at least one group selected from the group consisting of methylene groups and methine groups, or it may be composed of a polyether polyol containing two of at least one group selected from the group consisting of methylene groups and methine groups and a polyether polyol containing three or more of at least one group selected from the group consisting of methylene groups and methine groups. Examples of polyether polyols containing two of at least one group selected from the group consisting of methylene groups and methine groups include polyethylene glycol and polypropylene glycol. Examples of polyether polyols containing three or more of at least one group selected from the group consisting of methylene groups and methine groups include polytetramethylene glycol.

[0059] The polyfunctional isocyanate compound to be reacted with the polyol to obtain the urethane prepolymer may be one kind or two or more kinds.

[0060] The polyfunctional isocyanate compound may be any suitable polyfunctional isocyanate compound that can be used to prepare a urethane prepolymer, such as a polyfunctional aliphatic isocyanate compound, a polyfunctional alicyclic isocyanate compound, a polyfunctional aromatic isocyanate compound, or a polyfunctional araliphatic isocyanate compound.

[0061] 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.

[0062] Examples of polyfunctional alicyclic isocyanate compounds include 3-isocyanatemethyl-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(isocyanatemethyl)cyclohexane, 1,4-bis(isocyanatemethyl)cyclohexane, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

[0063] Examples of polyfunctional aromatic isocyanate 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'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4',4"-triphenylmethane triisocyanate, dianisidine diisocyanate, and xylylene diisocyanate.

[0064] 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.

[0065] Examples of the polyfunctional isocyanate compound include trimethylolpropane adducts of the above-mentioned various polyfunctional isocyanate compounds, biuret compounds obtained by reacting with water, and trimers having an isocyanurate ring. These may also be used in combination.

[0066] To prepare the urethane prepolymer, the polyfunctional isocyanate compound is preferably used in an equivalent ratio such that the isocyanate groups (NCO groups) of the polyol are in excess over the hydroxyl groups (OH groups) of the polyol. The NCO group / OH group equivalent ratio ([NCO] / [OH]) 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.

[0067] A catalyst may be used when preparing the urethane prepolymer. Any appropriate catalyst may be used as long as it does not impair the effects of the present invention. Examples of such catalysts include tertiary amine catalysts and organometallic catalysts. Only one type of catalyst may be used, or two or more types may be used.

[0068] Examples of the tertiary amine catalyst include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU).

[0069] Examples of the organometallic catalyst include bismuth-based catalysts such as bismuth octoate, bismuth neodecanoate, bismuth naphthenate, and bismuth rosinate; tin-based catalysts such as dibutyltin dilaurate (DBTDL) and dioctyltin dilaurate (DOTDL); titanium-based catalysts such as dibutyltitanium dichloride, tetrabutyl titanate, butoxytitanium trichloride, and titanium tetraacetylacetonate; iron-based catalysts such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt-based catalysts such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based catalysts such as zinc octoate, zinc naphthenate, and zinc 2-ethylhexanoate; and zirconium-based catalysts such as zirconium naphthenate.

[0070] When a catalyst is used in preparing the urethane prepolymer, the amount of the catalyst used is preferably 0.0001 to 1.0% by weight, more preferably 0.001 to 1.0% by weight, even more preferably 0.003 to 1.0% by weight, and particularly preferably 0.005 to 1.0% by weight, based on the total amount of the polyol and the polyfunctional isocyanate compound.

[0071] When a catalyst is used in preparing the urethane prepolymer, the reaction temperature is preferably less than 100° C., and more preferably 85° C. to 95° C. If the temperature is 100° C. or higher, it may become difficult to control the reaction rate and crosslinked structure.

[0072] When preparing the urethane prepolymer, it is not necessary to use a catalyst. In this case, the reaction temperature is preferably 100° C. or higher, more preferably 110° C. or higher. When preparing the urethane prepolymer without a catalyst, it is preferable to carry out the reaction for 3 hours or longer.

[0073] Any suitable method can be used to prepare the urethane prepolymer as long as it does not impair the effects of the present invention. Examples of such methods include 1) a method in which the entire amount of a polyol, a catalyst, and a polyfunctional isocyanate compound is charged into a reaction vessel, and 2) a method in which the polyol and a catalyst are charged into a reaction vessel and the polyfunctional isocyanate compound is added dropwise. In method 2), after the polyfunctional isocyanate compound has been added dropwise, additional polyol and polyfunctional isocyanate compound may be added.

[0074] Any suitable solvent may be used in preparing the urethane prepolymer, including, for example, methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone.

[0075] When preparing the urethane prepolymer, any appropriate other components may be used as long as they do not impair 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, antioxidants, 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, antioxidants, UV absorbers, and light stabilizers are preferred embodiments.

[0076] Examples of 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.

[0077] Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, oxalic acid anilide-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

[0078] Examples of the light stabilizer include hindered amine light stabilizers.

[0079] <A-1-2. Polyol as Base Polymer (A)> The polyol as the base polymer (A) can react with a polyfunctional isocyanate compound to form a one-shot urethane polymer.

[0080] The polyol may be one kind or two or more kinds.

[0081] Examples of the polyol include at least one selected from the group consisting of polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols, and preferably at least one selected from the group consisting of polyester polyols and polyether polyols.

[0082] The polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component. Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol. Examples of the acid component include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and acid anhydrides thereof.

[0083] Examples of polyether polyols include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide using as initiators water, low-molecular-weight polyols (ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcinol, hydroquinone, etc.), etc. Representative examples of polyether polyols include at least one selected from the group consisting of polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0084] Examples of polycaprolactone polyols include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

[0085] Examples of polycarbonate polyols include polycarbonate polyols obtained by polycondensation of the above polyol components with phosgene; polycarbonate polyols obtained by transesterification of the above polyol components with carbonate diesters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and dibenzyl carbonate; copolymer polycarbonate polyols obtained by combining two or more of the above polyol components; polycarbonate polyols obtained by esterification of the above various polycarbonate polyols with carboxyl group-containing compounds; and various Examples of the polycarbonate polyol include polycarbonate polyols obtained by etherifying polycarbonate polyols with hydroxyl group-containing compounds; polycarbonate polyols obtained by transesterifying the above-mentioned various polycarbonate polyols with ester compounds; polycarbonate polyols obtained by transesterifying the above-mentioned various polycarbonate polyols with hydroxyl group-containing compounds; polyester-based polycarbonate polyols obtained by polycondensation reaction of the above-mentioned various polycarbonate polyols with dicarboxylic acid compounds; and copolymerized polyether-based polycarbonate polyols obtained by copolymerizing the above-mentioned various polycarbonate polyols with alkylene oxides.

[0086] Examples of castor oil-based polyols include castor oil-based polyols obtained by reacting castor oil fatty acids with the above-mentioned polyol components.Specific examples include castor oil-based polyols obtained by reacting castor oil fatty acids with polypropylene glycol.

[0087] The number average molecular weight Mn of the polyol is preferably 300 to 100,000, more preferably 400 to 75,000, even more preferably 450 to 50,000, and particularly preferably 500 to 30,000, in order to further exhibit the effects of the present invention.

[0088] In order to further exert the effects of the present invention, the polyol preferably contains a polyol (a) having three OH groups and a number average molecular weight Mn of 300 to 100000. The polyol (a) may be one type or two or more types.

[0089] The content of polyol (a) in the polyol is preferably 5% by weight or more, more preferably 25% by weight to 100% by weight, even more preferably 50% by weight to 100% by weight, particularly preferably 70% by weight to 100% by weight, and most preferably 90% by weight to 100% by weight, in order to further exhibit the effects of the present invention.

[0090] In terms of being able to further exhibit the effects of the present invention, the polyol (a) preferably contains a polyol (a1) having three OH groups and a number average molecular weight Mn of 8000 to 20000. The polyol (a1) may be one type or two or more types.

[0091] The number average molecular weight Mn of the polyol (a1) is preferably 8,000 to 18,000, more preferably 8,500 to 16,000, even more preferably 8,500 to 14,000, particularly preferably 9,000 to 13,000, and most preferably 9,000 to 12,000, in terms of being able to further exhibit the effects of the present invention.

[0092] The content of polyol (a1) in the polyol is preferably 50% by weight or more, more preferably 60% by weight to 100% by weight, even more preferably 70% by weight to 95% by weight, particularly preferably 75% by weight to 93% by weight, and most preferably 80% by weight to 90% by weight, in terms of being able to further exhibit the effects of the present invention.

[0093] The polyol (a) may contain a polyol (a2) having three or more OH groups and a number average molecular weight Mn of 5,000 or less. The polyol (a2) is preferably at least one selected from the group consisting of a polyol (triol) having three OH groups, a polyol (tetraol) having four OH groups, a polyol (pentaol) having five OH groups, and a polyol (hexaol) having six OH groups. The polyol (a2) may be one type only, or two or more types.

[0094] The number average molecular weight Mn of the polyol (a2) is preferably 500 to 5,000, more preferably 600 to 4,500, even more preferably 700 to 4,000, particularly preferably 800 to 3,500, and most preferably 900 to 3,300, in order to further exhibit the effects of the present invention.

[0095] The content of polyol (a2) in the polyol is preferably 50% by weight or less, more preferably 0% by weight to 40% by weight, even more preferably 5% by weight to 30% by weight, particularly preferably 7% by weight to 25% by weight, and most preferably 10% by weight to 20% by weight, in terms of being able to further exhibit the effects of the present invention.

[0096] The content of the polyol having three OH groups (triol) in the polyol (a2) is preferably 80% by weight to 100% by weight, more preferably 90% by weight to 100% by weight, even more preferably 95% by weight to 100% by weight, particularly preferably 97% by weight to 100% by weight, and most preferably 99% by weight to 100% by weight, in terms of being able to further exhibit the effects of the present invention.

[0097] As the polyol (a2) having three OH groups (triol), it is preferable to use two types of triols in combination, one having a number average molecular weight Mn of 500 or more and less than 2000, and the other having a number average molecular weight Mn of 2000 to 5000, in order to further exhibit the effects of the present invention.

[0098] The number average molecular weight Mn of the triol having a number average molecular weight Mn of 500 or more but less than 2000 is preferably 600 to 1800, more preferably 700 to 1500, still more preferably 800 to 1300, and particularly preferably 900 to 1100.

[0099] The number average molecular weight Mn of the triol having a number average molecular weight Mn of 2000 to 5000 is preferably 2200 to 4500, more preferably 2400 to 4000, still more preferably 2600 to 3500, and particularly preferably 2800 to 3300.

[0100] The content of the triol having a number average molecular weight Mn of 500 or more and less than 2000 in the polyol is preferably 0.01% by weight to 20% by weight, more preferably 0.05% by weight to 15% by weight, even more preferably 0.1% by weight to 10% by weight, particularly preferably 0.5% by weight to 5% by weight, and most preferably 1% by weight to 3% by weight, in terms of being able to further exhibit the effects of the present invention.

[0101] The content of the triol having a number average molecular weight Mn of 2000 to 5000 in the polyol is preferably 1% by weight to 30% by weight, more preferably 2% by weight to 25% by weight, even more preferably 5% by weight to 20% by weight, particularly preferably 7% by weight to 20% by weight, and most preferably 9% by weight to 17% by weight, in terms of being able to further exhibit the effects of the present invention.

[0102] The polyol may contain a polyol having four or more OH groups and a number average molecular weight Mn of not more than 20000. The polyol having four or more OH groups and a number average molecular weight Mn of not more than 20000 may be one kind or two or more kinds.

[0103] <A-1-3. Polyfunctional Isocyanate Compound> The urethane-based pressure-sensitive adhesive composition typically contains a polyfunctional isocyanate compound. The polyfunctional isocyanate compound reacts with the base polymer (A) to form a urethane polymer. In particular, the polyfunctional isocyanate compound can react with a urethane prepolymer as the base polymer (A) to form a prepolymer-type urethane polymer, or can react with a polyol as the base polymer (A) to form a one-shot-type urethane polymer.

[0104] The polyfunctional isocyanate compound that reacts with the base polymer (A) may be one kind or two or more kinds.

[0105] The polyfunctional isocyanate compound to be reacted with the base polymer (A) may be any suitable polyfunctional isocyanate compound that can be used in a urethane-forming reaction, such as the polyfunctional isocyanate compounds that can be used in the preparation of the urethane prepolymer described above.

[0106] When a prepolymer-type urethane polymer is prepared by reacting a polyfunctional isocyanate compound with a urethane prepolymer as the base polymer (A), the equivalent ratio ([NCO] / [OH]) of the isocyanate groups (NCO groups) of the polyfunctional isocyanate compound to the hydroxyl groups (OH groups) of the urethane prepolymer is preferably 0.60 to 1.70, more preferably 0.70 to 1.70, even more preferably 0.75 to 1.70, still more preferably 1.00 to 1.70, still more preferably 1.10 to 1.65, particularly preferably 1.15 to 1.62, and most preferably 1.15 to 1.60, or even 1.20 to 1.60, 1.25 to 1.60, 1.30 to 1.60, 1.35 to 1.60, 1.40 to 1.60, or 1.45 to 1.60.

[0107] When a one-shot urethane polymer is prepared by reacting a polyfunctional isocyanate compound with a polyol as the base polymer (A), the equivalent ratio ([NCO] / [OH]) of the isocyanate groups (NCO groups) of the polyfunctional isocyanate compound to the hydroxyl groups (OH groups) of the polyol is preferably 1.00 to 3.00, more preferably 1.10 to 2.50, even more preferably 1.20 to 2.00, and particularly preferably 1.30 to 1.90.

[0108] When a prepolymer-type urethane polymer is prepared by reacting a polyfunctional isocyanate compound with a urethane prepolymer as the base polymer (A), the proportion of the polyfunctional isocyanate compound used relative to 100 parts by weight of the urethane prepolymer is preferably 1.0 to 15 parts by weight, more preferably 2.0 to 13 parts by weight, even more preferably 2.3 to 11 parts by weight, particularly preferably 2.6 to 10 parts by weight, and most preferably 2.8 to 9 parts by weight.

[0109] When a one-shot type urethane polymer is prepared by reacting a polyfunctional isocyanate compound with a polyol as the base polymer (A), the proportion of the polyfunctional isocyanate compound used relative to 100 parts by weight of the polyol is preferably 1 to 30 parts by weight, more preferably 5 to 25 parts by weight, even more preferably 8 to 22 parts by weight, particularly preferably 10 to 20 parts by weight, and most preferably 12 to 18 parts by weight.

[0110] The urethane polymer can be prepared by any suitable method as long as it is a method of curing a urethane-based pressure-sensitive adhesive composition containing a base polymer (A) and a polyfunctional isocyanate compound to form a urethane polymer, as long as the effects of the present invention are not impaired. For example, such a method includes a method in which a urethane-based pressure-sensitive adhesive composition containing a base polymer (A) and a polyfunctional isocyanate compound is applied to any suitable substrate, heated and dried as necessary, and cured as necessary, to form a pressure-sensitive adhesive layer on the substrate. The application method, heating and drying conditions, curing conditions, etc., can be appropriately selected from methods commonly known for forming pressure-sensitive adhesive layers.

[0111] <A-1-4. Catalyst> The urethane-based pressure-sensitive adhesive composition may contain a catalyst to promote the reaction between the base polymer (A) and the polyfunctional isocyanate compound. Any appropriate catalyst may be used as the catalyst as long as it does not impair the effects of the present invention. Examples of such catalysts include the catalysts that can be used in preparing the urethane prepolymer described above.

[0112] When a catalyst is used in preparing the urethane polymer, the content of the catalyst in the urethane-based pressure-sensitive adhesive composition is, in terms of solid content, preferably 0.0001 to 1.0 part by weight, more preferably 0.001 to 1.0 part by weight, still more preferably 0.003 to 1.0 part by weight, and particularly preferably 0.005 to 1.0 part by weight, relative to 100 parts by weight of the base polymer (A).

[0113] <A-1-5. Silicone Compound (B)> The urethane-based pressure-sensitive adhesive composition contains a silicone-based compound (B). The silicone-based compound (B) may be of one type only, or may be of two or more types.

[0114] The content of the silicone compound (B) in the urethane pressure-sensitive adhesive composition is, relative to 100 parts by weight of the base polymer (A), preferably 0.001 to 20 parts by weight, more preferably 0.005 to 10 parts by weight, even more preferably 0.01 to 7 parts by weight, still more preferably 0.02 to 4 parts by weight, particularly preferably 0.03 to 2 parts by weight, and most preferably 0.04 to 1 part by weight, calculated as solids. When the content of the silicone compound (B) in the urethane pressure-sensitive adhesive composition is within the above range, the effects of the present invention can be more effectively exhibited.

[0115] The silicone compound (B) typically contains at least one selected from the group consisting of reactive silicone oils and non-reactive silicone oils. The content of the at least one selected from the group consisting of reactive silicone oils and non-reactive silicone oils in the silicone compound (B) is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, even more preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably 98% to 100% by weight.

[0116] The silicone-based compound (B) may contain at least one type selected from the group consisting of reactive silicone oils and non-reactive silicone oils, as well as any other appropriate silicone-based compound within a range that does not impair the effects of the present invention.

[0117] Examples of reactive silicone oils include side-chain reactive silicone oils in which organic groups are bonded as side chains to Si atoms that participate in siloxane bonds, double-end reactive silicone oils in which organic groups are bonded to Si atoms located at both ends of the structure, single-end reactive silicone oils in which an organic group is bonded to only one of the Si atoms located at both ends of the structure, and side-chain double-end reactive silicone oils in which organic groups are bonded as side chains to Si atoms that participate in siloxane bonds and organic groups are bonded to Si atoms located at both ends of the structure.

[0118] 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. Examples of these commercially available products include various silicone oils available on the market as side-chain reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0119] As the double-end reactive silicone oil, for example, can be enumerated amino-modified double-end reactive silicone oil, epoxy-modified double-end reactive silicone oil, carbinol-modified double-end reactive silicone oil, methacrylic-modified double-end reactive silicone oil, polyether-modified double-end reactive silicone oil, mercapto-modified double-end reactive silicone oil, carboxyl-modified double-end reactive silicone oil, phenol-modified double-end reactive silicone oil, silanol-end double-end reactive silicone oil, acrylic-modified double-end reactive silicone oil, carboxylic anhydride-modified double-end reactive silicone oil.These commercially available products can be enumerated, for example, various silicone oils that are commercially available as double-end reactive silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.

[0120] The single-end reactive silicone oil may be, for example, a single-end reactive modified type silicone oil, an average single-end carboxyl modified type silicone oil, or a specific example may be a carbinol modified type silicone oil. Examples of commercially available products of these include various silicone oils available as single-end reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0121] Examples of the side chain both-end reactive silicone oil 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 of these include various silicone oils available as side chain both-end reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0122] Examples of non-reactive silicone oils include side-chain type non-reactive silicone oils in which organic groups are bonded as side chains to Si atoms that contribute to siloxane bonds, and double-end type non-reactive silicone oils in which organic groups are bonded to Si atoms located at both ends of the structure.

[0123] As the side-chain type non-reactive silicone oil, for example, can be enumerated polyether-modified side-chain type non-reactive silicone oil, aralkyl-modified side-chain type non-reactive silicone oil, fluoroalkyl-modified side-chain type non-reactive silicone oil, long-chain alkyl-modified side-chain type non-reactive silicone oil, higher fatty acid ester-modified side-chain type non-reactive silicone oil, higher fatty acid-containing side-chain type non-reactive silicone oil, phenyl-modified side-chain type non-reactive silicone oil.These commercially available products can be enumerated, for example, various silicone oils that are commercially available as side-chain type non-reactive silicone oil manufactured by Shin-Etsu Chemical Co., Ltd.

[0124] Examples of the dual-end non-reactive silicone oil include polyether-modified dual-end non-reactive silicone oils, such as those commercially available as dual-end non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0125] A preferred embodiment of the silicone compound (B) comprises at least one selected from the group consisting of silicone compounds having a polyether structure and silicone compounds having a carbinol structure. The content of the at least one selected from the group consisting of silicone compounds having a polyether structure and silicone compounds having a carbinol structure in the silicone compound (B) is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, even more preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably 98% to 100% by weight.

[0126] A more preferred embodiment of the silicone-based compound (B) includes a silicone-based compound having a polyether structure. The content of the silicone-based compound having a polyether structure in the silicone-based compound (B) is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, even more preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably 98% to 100% by weight. When the silicone-based compound (B) includes a silicone-based compound having a polyether structure, the surface protective film according to the embodiment of the present invention can exhibit better antistatic performance.

[0127] Examples of silicone compounds having a polyether structure include the above-mentioned polyether-modified both-end reactive silicone oil, polyether-modified side-chain non-reactive silicone oil, and polyether-modified both-end non-reactive silicone oil.

[0128] Commercially available polyether-modified, dual-end reactive silicone oils include, for example, "X-22-4952," "X-22-4272," and "KF-6123" manufactured by Shin-Etsu Chemical Co., Ltd.

[0129] Commercially available polyether-modified side chain non-reactive silicone oils include, for example, "KF-351A," "KF-352A," "KF-353," "KF-354L," "KF-355A," "KF-615A," "KF-945," "KF-640," "KF-642," "KF-643," "KF-644," "KF-6020," "KF-6204," "X-22-4515," "KF-6011," "KF-6012," "KF-6015," "KF-6017," and "X-22-2516," manufactured by Shin-Etsu Chemical Co., Ltd.

[0130] An example of a commercially available polyether-modified, dual-end non-reactive silicone oil is "KF-6004" manufactured by Shin-Etsu Chemical Co., Ltd.

[0131] Examples of silicone compounds having a carbinol structure include the above-mentioned carbinol-modified side chain reactive silicone oil, carbinol-modified both terminal reactive silicone oil, and carbinol-modified one terminal reactive silicone oil.

[0132] Commercially available carbinol-modified side-chain reactive silicone oils include, for example, "X-22-4039" and "X-22-4015" manufactured by Shin-Etsu Chemical Co., Ltd.

[0133] Commercially available carbinol-modified, dual-end reactive silicone oils include, for example, "KF-6000," "KF-6001," "KF-6002," and "KF-6003" manufactured by Shin-Etsu Chemical Co., Ltd.

[0134] Commercially available carbinol-modified single-end reactive silicone oils include, for example, "X-22-170BX" and "X-22-170DX" manufactured by Shin-Etsu Chemical Co., Ltd.

[0135] The silicone compound having a polyether structure that can be used as the silicone compound (B) is preferably at least one selected from the group consisting of reactive silicone oils and non-reactive silicone oils having an HLB value of not more than 15. When the silicone compound (B) is a silicone compound having a polyether structure and at least one selected from the group consisting of reactive silicone oils and non-reactive silicone oils having an HLB value of not more than 15, for example, the rate of increase in adhesive strength to glass plates over time can be further reduced, the increase in adhesive strength to the adherend over time can be further suppressed, and a surface protection film can be provided that adheres more appropriately and is easier to peel even after a long time has passed after being attached to the adherend.

[0136] Examples of silicone compounds that have a polyether structure and are reactive silicone oils include the aforementioned polyether-modified, dual-end reactive silicone oils.

[0137] As mentioned above, examples of commercially available polyether-modified dual-end reactive silicone oils include "X-22-4952," "X-22-4272," and "KF-6123" manufactured by Shin-Etsu Chemical Co., Ltd.

[0138] Examples of non-reactive silicone oils that are silicone compounds having a polyether structure and have an HLB value of 15 or less include the above-mentioned polyether-modified side-chain non-reactive silicone oils with an HLB value of 15 or less, and the above-mentioned polyether-modified double-end non-reactive silicone oils with an HLB value of 15 or less.

[0139] Examples of polyether-modified side-chain non-reactive silicone oils with an HLB value of 15 or less include "KF-351A" (HLB=12), "KF-352A" (HLB=7), "KF-353" (HLB=10), "KF-355A" (HLB=12), "KF-615A" (HLB=10), "KF-945" (HLB=4), "KF-640" (HLB=14), and "KF-642" manufactured by Shin-Etsu Chemical Co., Ltd. (HLB=12), "KF-643" (HLB=14), "KF-644" (HLB=11), "KF-6020" (HLB=4), "KF-6204" (HLB=10), "X-22-4515" (HLB=5), "KF-6011" (HLB=12), "KF-6012" (HLB=7), "KF-6015" (HLB=5), "KF-6017" (HLB=5), and "X-22-2516" (HLB=1).

[0140] An example of a polyether-modified, dual-terminal non-reactive silicone oil having an HLB value of 15 or less is "KF-6004" (HLB=9) manufactured by Shin-Etsu Chemical Co., Ltd.

[0141] <A-1-6. Ionic Compound (C)> The urethane-based pressure-sensitive adhesive composition contains an ionic compound (C). The ionic compound (C) may be one type only, or two or more types may be used.

[0142] The content of the ionic compound (C) in the urethane-based pressure-sensitive adhesive composition, calculated as solids, relative to 100 parts by weight of the base polymer (A), is preferably 0.01 to 5.0 parts by weight, more preferably 0.01 to 4.0 parts by weight, even more preferably 0.01 to 2.8 parts by weight, even more preferably 0.05 to 2.0 parts by weight, particularly preferably 0.1 to 1.0 part by weight, and most preferably 0.1 to 0.5 parts by weight. When the content of the ionic compound (C) in the urethane-based pressure-sensitive adhesive composition is within the above range, the effects of the present invention can be more effectively exhibited. When the content of the ionic compound (C) in the urethane-based pressure-sensitive adhesive composition is too high outside the above range, the haze of the surface protective film can increase, reducing the transparency of the surface protective film. For example, this may make it difficult to accurately inspect the surface protective film when attached to the surface of an adherend such as an optical component or an electronic component, or may increase the degree of contamination of the adherend. If the content of the ionic compound (C) in the urethane-based pressure-sensitive adhesive composition is too small and outside the above range, there is a risk that excellent antistatic properties may not be exhibited.

[0143] As the ionic compound (C), any appropriate ionic compound can be used as long as the effects of the present invention are not impaired. Such ionic compound (C) is preferably an ionic liquid. The ionic liquid refers to a molten salt (ionic compound) that is liquid at 25°C.

[0144] Any appropriate ionic liquid can be used as the ionic liquid 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 preferred, and an ionic liquid composed of a fluoroorganic anion and an onium cation is more preferred, in terms of being able to further exhibit the effects of the present invention.

[0145] As the ionic liquid, from the viewpoint of further exhibiting the effects of the present invention, preferred are 1-hexylpyridinium bis(fluorosulfonyl)imide, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl-3-methylpyridinium pentafluoroethanesulfonate, 1-ethyl-3-methylpyridinium heptafluoropropanesulfonate, 1-ethyl-3-methylpyridinium nonafluorobutanesulfonate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-octyl-4-methylpyridinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)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, and lithium bis(fluorosulfonyl)imide are more preferred, and 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide are more preferred.

[0146] The ionic liquid may be commercially available or synthesized. Examples of methods for synthesizing ionic liquids include general methods using a halide method, a hydroxide method, an acid ester method, a complex formation method, and a neutralization method, as described in the literature "Ionic Liquids - The Frontline and Future of Development" (published by CMC Publishing Co., Ltd.).

[0147] <A-1-7. Other Components> The urethane-based pressure-sensitive adhesive composition may contain any appropriate other components as long as the effects of the present invention are not impaired. Examples of such other components include solvents, crosslinking accelerators, silane coupling agents, fatty acid esters, antioxidants, UV absorbers, light stabilizers, resin components, tackifiers, crosslinking retarders, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), chain transfer agents, plasticizers, softeners, antioxidants, conductive agents, foil-like materials, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, and lubricants. The other components may be of only one type, or may be of two or more types.

[0148] <A-2. Substrate> The substrate may be a single layer or may be two or more layers. The substrate may be stretched.

[0149] The thickness of the substrate is preferably 4 μm to 450 μm, more preferably 8 μm to 400 μm, still more preferably 12 μm to 350 μm, and particularly preferably 16 μm to 250 μm.

[0150] For the surface of the substrate on which the pressure-sensitive adhesive layer is not applied, a release treatment can be performed by adding a fatty acid amide, polyethyleneimine, a long-chain alkyl additive, or the like to the substrate, or a coating layer made of any appropriate release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent can be provided, for example, in order to form a roll that can be easily unwound.

[0151] Any appropriate material can be used as the substrate material depending on the application. Examples include plastic, paper, metal film, nonwoven fabric, etc. Plastic is preferred. That is, the substrate is preferably a plastic film. The substrate 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.

[0152] Examples of the plastic include polyester resins, polyamide resins, polyolefin resins, etc. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.

[0153] The substrate may contain any appropriate additives as needed. Examples of additives that may be contained in the substrate 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 may be appropriately set depending on the purpose. In particular, when the substrate is made of plastic, it is preferable to contain some of the above-mentioned additives for the purpose of preventing deterioration, etc. From the viewpoint of improving weather resistance, etc., particularly preferred additives include antioxidants, UV absorbers, light stabilizers, and fillers.

[0154] <<B. Uses>> The surface protective film according to an embodiment of the present invention is typically attached to an exposed surface of an optical or electronic component in the manufacturing process of the optical or electronic component to prevent the surface of the optical or electronic component from being scratched during processing, assembly, inspection, transportation, etc., and can be suitably used for surface protection of the optical or electronic component. The optical component of the present invention has the surface protective film of the present invention attached thereto. The electronic component of the present invention has the surface protective film of the present invention attached thereto.

[0155] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows. The term "parts" means "parts by weight" unless otherwise specified, and the term "%" means "% by weight" unless otherwise specified.

[0156] <Measurement of Surface Resistivity to Glass Plate> In an environment of 23°C and 50% RH, the surface protective film from which the release liner had been peeled was cut to a size of 100 mm x 100 mm and pressed onto the surface of a glass plate (soda lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) using a 2 kg hand roller to prepare a sample. This sample was left in an environment of 23°C and 50% RH for 4 hours, and then the surface protective film was peeled off from the glass plate. In an environment of 23°C and 50% RH, the terminals of a surface resistance meter (manufactured by Nitto Seiko Analytech Co., Ltd., model "Hiresta-UX MCP-HT800") were pressed against the center of the peeled surface of the glass plate after peeling, and a voltage of 250 V was applied for 10 seconds, after which the surface resistance was measured and recorded as the surface resistance to the glass plate. In Tables 1 and 2, the notation "aE+b" represents "a×10 b The measurement limit of the device is 1.0 x 10 12 When the measurement result exceeded this measurement limit, it was expressed as "1.0E+12<" in Tables 1 and 2.

[0157] <Measurement of Glass Plate Peeling Electrostatic Potential> In an environment of 23 ° C. and 50% RH, the surface protective film from which the release liner had been peeled was cut to a size of 70 mm wide x 100 mm long, and a sample was obtained by pressing one end of the surface protective film onto the surface of a glass plate (soda lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2 kg hand roller so that one end of the surface protective film protruded 30 mm from the edge of the glass plate. This sample was left in an environment of 23 ° C. and 50% RH for 1 day and then set on a sample fixing table with a height of 20 mm. The end of the surface protective film protruding 30 mm from the glass plate was fixed to an automatic winder, and the film was peeled at a peel angle of 150 degrees and a peel speed of 15 m / min. The potential of the glass plate surface generated at this time was measured using a potential meter (manufactured by Shishido Electrostatics Co., Ltd., model "STATIRON DZ-4") fixed at a position 30 mm above the center of the glass plate, and this was taken as the glass plate peeling electrostatic potential. The measurement was carried out in an environment of 23° C. and 50% RH.

[0158] <Measurement of Amount of Elemental Sulfur Transferred to Glass Plate> In an environment of 23°C and 50% RH, the surface protective film from which the release liner had been peeled was cut into a 10 mm x 10 mm piece, and a sample was obtained by pressing the film against the surface of a glass plate (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2 kg hand roller in one stroke. This sample was left for 30 minutes in an environmental temperature of 23°C, and then the surface protective film was peeled from the glass plate in an environment of 23°C and 50% RH. The peeled surface of the glass plate after peeling was subjected to narrow scan measurement using ESCA, and the element ratio (atomic %) was calculated. Apparatus: Quantera SXM (ULVAC-PHI) X-ray source: Monochrome Al Ka ​​X-ray setting: 100 μmφ [15 kV, 25 W] Photoelectron take-off angle: 45 degrees to the sample surface Neutralization conditions: Neutralization gun and Ar ion gun (neutralization mode) used in combination Bond energy correction: The peak derived from the C-C bond in the C1s spectrum was corrected to 285.0 eV

[0159] <Measurement of fluorine content in adhesive layer> Approximately 10 mg of adhesive was picked from the adhesive layer of the surface protection film from which the release liner had been peeled off, placed in a ceramic boat, weighed, and then 100 mg of a combustion improver (tungsten (VI) oxide (powder), manufactured by Kishida Chemical Co., Ltd.) was added. Next, the mixture was combusted using an automatic sample combustion apparatus (AQF-2100H, manufactured by Nitto Seiko Analytech Co., Ltd.), and the generated gas was collected in 10 mL of absorption liquid. Temperature: Inlet 1000°C / Outlet 1100°C Gas flow rate: O2 400 mL / min, Ar 200 mL / min, Ar water supply unit 100 mL / min After collection, ultrapure water was added to the absorption liquid to adjust the volume to 15 mL, and the adjusted liquid and a further appropriately diluted liquid were quantitatively analyzed using IC (ICS-3000, manufactured by Thermo Fisher Scientific) to determine the fluorine content in the adhesive layer. Separation column and guard column: Dionex IonPac AS18-fast (4 mm x 150 mm) / Dionex IonPac AG18-fast (4 mm x 30 mm) Removal system: Dionex ADRS-600 Detector: Electrical conductivity detector Eluent composition: KOH aqueous solution Eluent flow rate: 1.2 mL / min Sample injection volume: 250 μL

[0160] <Measurement of Adhesion Strength to Glass Plate (I) (After Standing at 23°C for 30 Minutes)> In an environment of 23°C and 50% RH, the release liner was peeled off from the surface protective film, and the surface protective film was cut to a width of 25 mm and a length of 140 mm. The surface protective film was then pressed against the surface of a glass plate (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) using a 2 kg hand roller in one stroke to obtain a sample. After leaving the sample at an environmental temperature of 23°C for 30 minutes, the sample was placed in a tensile tester, and a tensile test was initiated. The tensile test conditions were an environment of 23°C and 50% RH, a peel angle of 180°, and a peel rate (pulling rate) of 300 mm / min. The peel force (load) when the surface protective film was peeled from the glass plate was measured, and the average peel force (average load) at this time was taken as the adhesion strength to glass plate (I) (sometimes simply referred to as the adhesion strength (I)). The tensile tester used was an Autograph AG-Xplus HS 6000 mm / min high speed model (AG-50NX plus) manufactured by Shimadzu Corporation.

[0161] <Measurement of Adhesion Strength to Glass Plate (II) (After Leaving at 50°C for 1 Day)> In an environment of 23°C and 50% RH, the release liner was peeled off from the surface protective film, and the surface protective film was cut to a width of 25 mm and a length of 140 mm. The surface protective film was then pressed against the surface of a glass plate (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) using a 2 kg hand roller in one stroke to obtain a sample. After leaving the sample at an environmental temperature of 50°C for 1 day, the sample was placed in a tensile tester, and a tensile test was initiated. The tensile test conditions were an environment of 23°C and 50% RH, a peel angle of 180°, and a peel rate (pulling rate) of 300 mm / min. The peel force (load) when the surface protective film was peeled from the glass plate was measured, and the average peel force (average load) at this time was taken as the adhesion strength to glass plate (II) (sometimes simply referred to as adhesion strength (II)). The tensile tester used was an Autograph AG-Xplus HS 6000 mm / min high speed model (AG-50NX plus) manufactured by Shimadzu Corporation.

[0162] <Calculation of the rate of increase over time in adhesive strength to glass plate> Calculation was performed using the formula [adhesive strength (II) / adhesive strength (I)]×100(%).

[0163] <Measurement of No. 31B High-Temperature, Low-Speed ​​Adhesion to Glass Plate> In an environment of 23°C and 50% RH, the release liner was removed from the surface protective film, which was cut into a 100 mm x 100 mm piece. This was then pressed against the surface of a glass plate (soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) using a 2 kg hand roller in one stroke. After leaving the film at 23°C for one day, the surface protective film was peeled from the glass plate in an environment of 23°C and 50% RH. No. 31B adhesive tape (manufactured by Nitto Denko Corporation) was then applied to the peeled surface of the glass plate using a 2 kg hand roller in one stroke to prepare a sample. This sample was placed in a tensile tester equipped with a thermostatic chamber, product name "Autograph AG-Xplus" manufactured by Shimadzu Corporation. The temperature inside the thermostatic chamber was set to 85°C, and the test was started after 5 minutes. The conditions for the tensile test were a peel angle of 180° and a peel speed (pulling speed) of 10 mm / min. The peel force (load) when the No. 31B pressure-sensitive adhesive tape was peeled from the glass plate was measured, and the average peel force (average load) was taken as the high-temperature, low-speed adhesive strength of No. 31B to the glass plate.

[0164] <Measurement of Haze> The release liner was removed from the surface protection film in an environment of 23° C. and 50% RH, and the surface protection film was cut into a size of 50 mm×50 mm, and the haze was measured using an HM-150N manufactured by Murakami Color Research Laboratory.

[0165] [Production Example 1]: Production of urethane prepolymer A An experimental apparatus equipped with a 1 L round-bottom separable flask, a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade was charged with 260 g of polytetramethylene glycol (product name "PTMG3000" manufactured by Mitsubishi Chemical Corporation), 173 g of polypropylene glycol (product name "SANNIX GP-1500" manufactured by Sanyo Chemical Industries, Ltd.), and 150 g of ethyl acetate (manufactured by Tosoh Corporation) as a solvent, and while stirring, 0.05 g of bismuth octoate (manufactured by Nippon Chemical Industry Co., Ltd.) was added as a catalyst, and the mixture was purged with nitrogen at room temperature for 1 hour. Thereafter, under nitrogen flow and stirring, 15 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and polymerization was carried out for 4 hours while controlling the temperature of the solution in the experimental apparatus to 90±2°C in a water bath, to obtain a solution of urethane prepolymer A. During the polymerization, ethyl acetate was added dropwise as needed to control the temperature during polymerization and to prevent a decrease in stirrability due to an increase in viscosity. The total amount of ethyl acetate added was 300 g. The solids concentration of the urethane prepolymer A solution was 50 wt%.

[0166] [Production Example 2]: Production of urethane prepolymer B An experimental apparatus equipped with a 1 L round-bottom separable flask, a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade was charged with 347 g of polypropylene glycol (product name "Sanix PP-2000" manufactured by Sanyo Chemical Industries, Ltd.), 47 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 bismuth octoate (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, and the mixture was purged with nitrogen at room temperature for 1 hour with stirring. Thereafter, under nitrogen flow and stirring, 33.5 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the temperature of the solution in the experimental apparatus was maintained at 90±2°C in a water bath while maintaining the temperature for 4 hours. Thereafter, 44 g of polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Industries, Ltd.) was added, and the temperature of the solution in the experimental apparatus was maintained at 90±2°C in a water bath while maintaining the temperature for 2 hours. Thereafter, 25.4 g of hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation) was added, and the temperature of the solution in the experimental apparatus was maintained at 90±2°C in a water bath while maintaining the temperature for 2 hours, thereby obtaining a solution of urethane prepolymer B. Note that toluene was added dropwise as needed during the polymerization to control the temperature during polymerization and to 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 urethane prepolymer B solution was 50 wt%.

[0167] [Example 1] 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of KF-354L (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industries Co., Ltd.) as a catalyst were blended, and the mixture was diluted with ethyl acetate to a total solids content of 50% by weight, to obtain a urethane-based pressure-sensitive adhesive composition (1). The urethane-based pressure-sensitive adhesive composition (1) was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying would be 75 μm, and the coating was cured and dried under conditions of a drying temperature of 150°C and a drying time of 3 minutes to produce a pressure-sensitive adhesive layer (1). 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 with one side silicone-treated and having a thickness of 25 μm was laminated to the surface of the obtained pressure-sensitive adhesive layer (1), to obtain a surface protection film (1). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0168] Example 2 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of KF-640 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industries Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (2). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (2) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (2) and a surface protective film (2). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0169] Example 3 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of X-22-4515 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industries Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (3). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (3) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (3) and a surface protective film (3). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0170] Example 4 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of KF-6001 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industries Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (4). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (4) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (4) and a surface protective film (4). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0171] Example 5 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of X-22-4272 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (5). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (5) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (5) and a surface protective film (5). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0172] Example 6 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a multifunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries 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, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (6). The procedure of Example 1 was repeated except that the urethane-based pressure-sensitive adhesive composition (6) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (6) and a surface protection film (6). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0173] Example 7 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries 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, 1.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industries Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (7). The procedure of Example 1 was repeated except that the urethane-based pressure-sensitive adhesive composition (7) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (7) and a surface protective film (7). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0174] Example 8 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries 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, 3.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (8). The procedure of Example 1 was repeated except that the urethane-based pressure-sensitive adhesive composition (8) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (8) and a surface protective film (8). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0175] Example 9 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries 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, 0.30 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (9). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (9) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (9) and a surface protective film (9). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0176] [Example 10] 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries 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, 0.30 parts by weight of CIL312 (manufactured by Nippon Carlit Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (10). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (10) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (10) and a surface protective film (10). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0177] [Example 11] 100 parts by weight of urethane prepolymer B, 3.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries 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, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (11). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (11) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (11) and a surface protective film (11). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0178] [Example 12] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, were used. A mixture of 14.6 parts by weight of a silicone compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.), 0.12 parts by weight of Nursem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 0.10 parts by weight of KF-354L (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, and 1.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent was diluted with ethyl acetate to a total solids content of 35% by weight to obtain a urethane-based pressure-sensitive adhesive composition (12). The urethane-based pressure-sensitive adhesive composition (12) was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a thickness of 20 μm after drying, and cured and dried at a drying temperature of 130°C for 2 minutes to produce a pressure-sensitive adhesive layer (12). Next, the silicone-treated surface of a release sheet (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) made of a 25 μm thick polyester resin with one side silicone-treated was laminated to the surface of the obtained pressure-sensitive adhesive layer (12) to obtain a surface protection film (12). Aging was carried out at room temperature for 5 days and then evaluation was carried out. The results are shown in Tables 1 and 2.

[0179] [Example 13] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, were used. A urethane-based pressure-sensitive adhesive composition (13) was obtained by blending 14.6 parts by weight of a carboxylate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Co., Ltd.), 0.12 parts by weight of Narcem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 0.10 parts by weight of KF-640 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, and 1.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, and diluting with ethyl acetate to a total solids content of 35% by weight. A pressure-sensitive adhesive layer (13) and a surface protection film (13) were obtained in the same manner as in Example 12, except that urethane-based pressure-sensitive adhesive composition (13) was used instead of urethane-based pressure-sensitive adhesive composition (12). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0180] [Example 14] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, and polyfunctional isocyanate as a crosslinking agent. A compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Co., Ltd.): 14.6 parts by weight, a catalyst: Narcem ferric (manufactured by Nippon Chemical Industry Co., Ltd.): 0.12 parts by weight, a silicone compound: X-22-4515 (manufactured by Shin-Etsu Chemical Co., Ltd.): 0.10 parts by weight, and an antistatic agent: AS100 (manufactured by Nippon Nyukazai Co., Ltd.): 1.00 parts by weight were blended and diluted with ethyl acetate to a total solids content of 35% by weight to obtain a urethane-based pressure-sensitive adhesive composition (14). The procedure of Example 12 was repeated except that the urethane-based pressure-sensitive adhesive composition (14) was used instead of the urethane-based pressure-sensitive adhesive composition (12), to obtain a pressure-sensitive adhesive layer (14) and a surface protection film (14). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0181] [Example 15] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, were used. A urethane-based pressure-sensitive adhesive composition (15) was obtained by blending 14.6 parts by weight of a silicone compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a catalyst, 0.12 parts by weight of Narcem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 0.10 parts by weight of KF-6001 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, and 1.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, and diluting with ethyl acetate to a total solids content of 35% by weight. A pressure-sensitive adhesive layer (15) and a surface protective film (15) were obtained in the same manner as in Example 12, except that urethane-based pressure-sensitive adhesive composition (15) was used instead of urethane-based pressure-sensitive adhesive composition (12). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0182] [Example 16] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, and polyfunctional isocyanate as a crosslinking agent. A compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.): 14.6 parts by weight, a catalyst: Narcem ferric (manufactured by Nippon Chemical Industry Co., Ltd.): 0.12 parts by weight, a silicone compound: X-22-4272 (manufactured by Shin-Etsu Chemical Co., Ltd.): 0.10 parts by weight, and an antistatic agent: AS100 (manufactured by Nippon Nyukazai Co., Ltd.): 1.00 parts by weight were blended, and the mixture was diluted with ethyl acetate to a total solids content of 35% by weight to obtain a urethane-based pressure-sensitive adhesive composition (16). The same procedure as in Example 12 was carried out, except that the urethane-based pressure-sensitive adhesive composition (16) was used instead of the urethane-based pressure-sensitive adhesive composition (12), to obtain a pressure-sensitive adhesive layer (16) and a surface protection film (16). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0183] [Example 17] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, were used. A urethane-based pressure-sensitive adhesive composition (17) was obtained by blending 14.6 parts by weight of a silicone compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.), 0.12 parts by weight of Nursem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, and 1.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, and diluting with ethyl acetate to a total solids content of 35% by weight. A pressure-sensitive adhesive layer (17) and a surface protection film (17) were obtained in the same manner as in Example 12, except that urethane-based pressure-sensitive adhesive composition (17) was used instead of urethane-based pressure-sensitive adhesive composition (12). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0184] [Example 18] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, were used. A urethane-based pressure-sensitive adhesive composition (18) was obtained by blending 14.6 parts by weight of a silicone compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a catalyst, 0.12 parts by weight of Narcem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, and 3.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, and diluting with ethyl acetate to a total solids content of 35% by weight. A pressure-sensitive adhesive layer (18) and a surface protection film (18) were obtained in the same manner as in Example 12, except that urethane-based pressure-sensitive adhesive composition (18) was used instead of urethane-based pressure-sensitive adhesive composition (12). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0185] [Example 19] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, were used. A urethane-based pressure-sensitive adhesive composition (19) was obtained by blending 14.6 parts by weight of a silicone compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.), 0.12 parts by weight of Nursem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 0.10 parts by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone compound, and 1.00 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, and diluting with ethyl acetate to a total solids content of 35% by weight. The same procedure as in Example 12 was repeated, except that urethane-based pressure-sensitive adhesive composition (19) was used instead of urethane-based pressure-sensitive adhesive composition (12), to obtain a pressure-sensitive adhesive layer (19) and a surface protection film (19). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0186] [Example 20] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, and polyfunctional isocyanate as a crosslinking agent. A compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.): 14.6 parts by weight, Narcem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.): 0.12 parts by weight as a catalyst, KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.): 0.10 parts by weight as a silicone compound, and CIL312 (manufactured by Nippon Carlit Co., Ltd.): 1.00 parts by weight as an antistatic agent were blended, and the mixture was diluted with ethyl acetate to a total solids content of 35% by weight, thereby obtaining a urethane-based pressure-sensitive adhesive composition (20).

[0187] Comparative Example 1 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (C1). The same procedure as in Example 1 was repeated, except that the urethane-based pressure-sensitive adhesive composition (C1) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (C1) and a surface protection film (C1). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0188] Comparative Example 2 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 1.00 parts by weight of Megafac F-477 (manufactured by DIC Corporation) as a fluorine-based compound, 0.30 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (C2). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (C2) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (C2) and a surface protective film (C2). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0189] Comparative Example 3 100 parts by weight of urethane prepolymer A, 4.0 parts by weight of a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Industries Co., Ltd.) as a crosslinking agent, 1.00 parts by weight of Megafac F-477 (manufactured by DIC Corporation) as a fluorine-based compound, 0.30 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent, 0.50 parts by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 parts by weight of Nikka Octix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst were blended and diluted with ethyl acetate to a total solids content of 50% by weight to obtain a urethane-based pressure-sensitive adhesive composition (C3). The same procedure as in Example 1 was carried out, except that the urethane-based pressure-sensitive adhesive composition (C3) was used instead of the urethane-based pressure-sensitive adhesive composition (1), to obtain a pressure-sensitive adhesive layer (C3) and a surface protective film (C3). Aging was carried out at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0190] [Comparative Example 4] As a polyol, Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), which is a polyol having three hydroxyl groups: 85 parts by weight, Sannix GP3000 (manufactured by Sanyo Chemical Industries, Mn = 3000), which is a polyol having three hydroxyl groups: 13 parts by weight, Sannix GP1000 (manufactured by Sanyo Chemical Industries, Mn = 1000), which is a polyol having three hydroxyl groups: 2 parts by weight, a polyfunctional isocyanate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Co., Ltd.) as a crosslinking agent: 14.6 parts by weight, and Nursem ferric iron (manufactured by Nippon Chemical Industries Co., Ltd.) as a catalyst: 0.12 parts by weight. The mixture was diluted with ethyl acetate to a total solids content of 35% by weight to obtain a urethane-based adhesive composition (C4). A pressure-sensitive adhesive layer (C4) and a surface protection film (C4) were obtained in the same manner as in Example 12, except that the urethane-based pressure-sensitive adhesive composition (C4) was used instead of the urethane-based pressure-sensitive adhesive composition (12). Aging was carried out at room temperature for 5 days, and various evaluations were carried out. The results are shown in Tables 1 and 2.

[0191] Comparative Example 5 A mixture of 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn=10,000), a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn=3,000), a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn=1,000), a polyol having three hydroxyl groups, and a polyfunctional isocyanate as a crosslinking agent was used. A urethane-based pressure-sensitive adhesive composition (C5) was obtained by blending 14.6 parts by weight of a carboxylate compound (Coronate HX (C / HX), manufactured by Nippon Polyurethane Co., Ltd.), 0.12 parts by weight of Narcem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 2.00 parts by weight of Megafac F-477 (manufactured by DIC Corporation) as a fluorine-based compound, and 1.00 parts by weight of AS100 (manufactured by Nippon Nyukazai Co., Ltd.) as an antistatic agent, and diluting with ethyl acetate to a total solids content of 35% by weight. A pressure-sensitive adhesive layer (C5) and a surface protective film (C5) were obtained in the same manner as in Example 12, except that the urethane-based pressure-sensitive adhesive composition (C5) was used instead of the urethane-based pressure-sensitive adhesive composition (12). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0192] [Comparative Example 6] As a polyol, 85 parts by weight of Preminol S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10,000), which is a polyol having three hydroxyl groups, 13 parts by weight of Sannix GP3000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 3,000), which is a polyol having three hydroxyl groups, and 2 parts by weight of Sannix GP1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1,000), which is a polyol having three hydroxyl groups, were used. A mixture of 14.6 parts by weight of a urethane-based adhesive (Coronate HX:C / HX, manufactured by Nippon Polyurethane Industries Co., Ltd.), 0.12 parts by weight of Narcem ferric salt (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst, 2.00 parts by weight of Megafac F-477 (manufactured by DIC Corporation) as a fluorine-based compound, and 1.00 parts by weight of Elexcel AS110 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an antistatic agent was blended and diluted with ethyl acetate to a total solids content of 35% by weight to obtain a urethane-based adhesive composition (C6). A pressure-sensitive adhesive layer (C6) and a surface protective film (C6) were obtained in the same manner as in Example 12, except that the urethane-based adhesive composition (C6) was used instead of the urethane-based adhesive composition (12). Aging was performed at room temperature for 5 days, and various evaluations were performed. The results are shown in Tables 1 and 2.

[0193]

[0194]

[0195] [Examples 21 to 40] For each of the surface protection films (1) to (20) obtained in Examples 1 to 20, 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 member, to obtain an optical member with the surface protection film attached.

[0196] [Examples 41 to 60] For each of the surface protection films (1) to (20) obtained in Examples 1 to 20, 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 with a surface protection film attached thereto.

[0197] The surface protective film of the present invention can be used for any suitable application, and is preferably used in the fields of optical members and electronic members.

Claims

1. A surface protection film including an adhesive layer composed of a urethane-based adhesive, the urethane-based adhesive including a urethane polymer, the urethane-based adhesive being formed from a urethane-based adhesive composition, the urethane-based adhesive composition including a base polymer (A), a silicone-based compound (B), and an ionic compound (C), wherein the surface protection film is attached to a glass plate and left for 4 hours in an environment of a temperature of 23°C and a humidity of 50% RH, and then the surface protection film is peeled off from the glass plate. After a voltage of 250 V is applied to the center of the peeled surface of the glass plate for 10 seconds, the surface resistance value is 5.0 x 10 10 Ω or more.

2. The surface protective film according to claim 1, wherein the fluorine content in the pressure-sensitive adhesive layer is 0.20% by weight or less.

3. The surface protection film according to claim 1, wherein the urethane polymer is a prepolymer type urethane polymer, and wherein, when the adhesive layer is attached to a glass plate, left for 30 minutes at an environmental temperature of 23°C, and then the surface protection film is peeled off from the glass plate at a peel angle of 180° and a peel speed of 300 mm / min, the average peel force is defined as adhesive force (I), and the adhesive layer is attached to a glass plate, left for 1 day at an environmental temperature of 50°C, and then the average peel force is peeled off from the glass plate at a peel angle of 180° and a peel speed of 300 mm / min, the rate of increase over time in adhesive force to the glass plate, defined as [adhesive force (II) / adhesive force (I)] x 100 (%), is less than 210%.

4. The surface protection film according to claim 1, wherein the urethane polymer is a one-shot type urethane polymer, and wherein, when the adhesive layer is attached to a glass plate, left for 30 minutes at an environmental temperature of 23°C, and then the surface protection film is peeled off from the glass plate at a peel angle of 180° and a peel speed of 300 mm / min, the average peel force is defined as adhesive force (I), and the adhesive layer is attached to a glass plate, left for 1 day at an environmental temperature of 50°C, and then the average peel force is peeled off from the glass plate at a peel angle of 180° and a peel speed of 300 mm / min, the rate of increase over time in adhesive force to the glass plate, defined as [adhesive force (II) / adhesive force (I)] x 100 (%), is less than 160%.

5. The surface protective film according to claim 1, wherein the content of the ionic compound (C) is 0.01 to 2.8 parts by weight based on 100 parts by weight of the base polymer (A).

6. The surface protective film according to claim 1, wherein the silicone compound (B) comprises a silicone compound having a polyether structure.

7. The surface protective film according to claim 6, wherein the silicone compound having a polyether structure is at least one selected from the group consisting of reactive silicone oils and non-reactive silicone oils having an HLB value of 15 or less.

8. An optical member comprising the surface protective film according to any one of claims 1 to 7.

9. An electronic component comprising the surface protection film according to any one of claims 1 to 7.

Images