Surface protective film

Abstract

Provided is a surface protective film which comprises an adhesive layer, and which can exhibit both excellent anchoring force and suppression of the occurrence of spunlaces during cutting. A surface protective film according to an embodiment of the present invention comprises an adhesive layer comprising a urethane-based adhesive comprising a urethane polymer, the urethane-based adhesive being formed from a urethane-based adhesive composition, the urethane-based adhesive composition contains a base polymer (A) and a silicone-based compound (B), the base polymer (A) being a urethane prepolymer obtained by reacting a polyfunctional isocyanate compound with a polyol including a polyester polyol (a1) and a polyether polyol (a2), the polyether polyol (a2) contains a polyol (a3) containing three or more groups selected from the group consisting of methylene groups and methine groups.

Description

TECHNICAL FIELD

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

[0002] In a manufacturing process of an optical member, an electronic member, in order to prevent the surface of the optical member, the electronic member from being scratched at the time of processing, assembling, inspecting, transporting, and the like, a surface protection film is usually attached to the exposed surface of the optical member, the electronic member. Such a surface protection film is peeled from the optical member, the electronic member at a point in time when surface protection is not required (Patent Document 1).

[0003] At the time of peeling the surface protection film from the optical member, the electronic member to which the surface protection film is attached, it is required that the peeling is smooth only at the interface between the surface protection film and the optical member, the electronic member, that is, easy peeling property.

[0004] As a method of imparting easy peeling property to a surface protection film, in the past, a technique of adding a fluorine-based compound, a silicone-based compound to an adhesive composition which forms an adhesive constituting an adhesive layer has been reported (Patent Documents 2, 3). However, the conventional additive for imparting such easy peeling property not only exists on the surface side of the adhesive layer, but also exists on the substrate side, and there is a problem that the anchoring force between the substrate and the adhesive layer is reduced.

[0005] On the other hand, if the design of making the adhesive itself constituting the adhesive layer hard is performed in order to impart easy peeling property to the surface protection film, the adhesive layer is difficult to adhere to the substrate, and in this case, there is a problem that the anchoring force between the substrate and the adhesive layer is reduced.

[0006] Further, as a preferred adhesive constituting an adhesive layer possessed by a surface protection film mainly used for the purpose of being attached to the exposed surface of an optical member, an electronic member, a urethane-based adhesive is known (Patent Documents 1 to 3). However, a surface protection film including an adhesive layer constituted by a conventional urethane-based adhesive has a problem that a gum is sometimes generated at the time of cutting, and process defects are easily caused.

[0007] PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: Japanese Patent No. 6613516 Patent Document 2: Japanese Patent No. 6368810 Patent Document 3: Japanese Patent No. 6648168 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION The present application has a technical problem to provide a surface protective film including an adhesive layer, which can achieve both excellent anchoring force and suppression of generation of adhesive residue at the time of cutting.

[0009] Solution to the problem [1] The surface protective film of the embodiment of the present application includes an adhesive layer composed of a urethane-based adhesive containing a urethane polymer, which is formed from a urethane-based adhesive composition containing a base polymer (A) and a silicone-based compound (B), the base polymer (A) being a urethane prepolymer obtained by reacting a polyol containing a polyester polyol (al) and a polyether polyol (a2) containing a polyol (a3) containing three or more groups selected from the group consisting of methylene and methine with a polyfunctional isocyanate compound.

[0010] [2] The surface protective film according to the above-mentioned [1] can also be such that the content ratio of the polyester polyol (al) in the above-mentioned polyol is 0.01 to 10.0% by weight.

[0011] [3] The surface protective film according to the above-mentioned [1] or [2] can also be such that the above-mentioned urethane-based adhesive composition contains a catalyst which is at least one selected from the group consisting of zinc-based catalysts and titanium-based catalysts.

[0012] [4] The surface protective film according to any one of the above-mentioned [1] to [3] can also be such that, when the above-mentioned adhesive layer 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 from the glass plate at a peeling angle of 180 degrees and a peeling speed of 300 mm / minute, the average peeling force at this time is defined as the adhesive force (I), and when the above-mentioned adhesive layer is attached to a glass plate and 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 peeling angle of 180 degrees and a peeling speed of 300 mm / minute, the average peeling force at this time is defined as the adhesive force (II), and at this time, the rate of increase in the adhesive force to the glass plate with time, which is defined by [adhesive force (II) / adhesive force (I)] x 100 (%), is less than 210%.

[0013] [5] The surface protective film according to any one of the above-mentioned [1] to [4] can also be such that the above-mentioned silicone-based compound (B) contains at least one selected from the group consisting of a reactive silicone oil having at least one selected from the group consisting of a polyether structure and a methanol structure, and a non-reactive silicone oil having a polyether structure and an HLB value of 15 or less.

[0014] [6] can also be the surface protective film according to any one of the above [1] to [5], wherein the surface free energy of the surface of the above-mentioned adhesive layer with respect to diiodomethane is 2.5 mJ / m 2 ~ 20.0 mJ / m 2 .

[0015] [7] can also be the surface protective film according to any one of the above [1] to [6], wherein the content of the above-mentioned organosilicon compound (B) with respect to 100 parts by weight of the above-mentioned base polymer (A) is 0.01 parts by weight ~ 0.48 parts by weight.

[0016] [8] the optical member of the embodiment of the present invention includes the surface protective film according to any one of the above [1] to [7].

[0017] [9] the electronic member of the embodiment of the present invention includes the surface protective film according to any one of the above [1] to [7].

[0018] Effects of the Invention According to the present invention, it is possible to provide a surface protective film including an adhesive layer, which can achieve both excellent anchoring force and suppression of generation of adhesive dregs at the time of cutting. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic cross-sectional view of the surface protective film of the embodiment of the present invention. DETAILED DESCRIPTION

[0020] In the case where the expression "weight" exists in the present specification, it can also be replaced with "mass" which is a SI-based unit for indicating weight.

[0021] In the case where the expression "(methyl)acrylic acid" exists in the present specification, it means "acrylic acid and / or methacrylic acid", in the case where the expression "(methyl)acrylate" exists, it means "acrylate and / or methacrylate", in the case where the expression "(methyl)allyl" exists, it means "allyl and / or methallyl", and in the case where the expression "(methyl)acrolein" exists, it means "acrolein and / or methacrolein".

[0022] 《《A. Surface protective film》 The surface protective film of the embodiment of the present invention includes an adhesive layer composed of a urethane-based adhesive. In the surface protective film of the embodiment of the present invention, the urethane-based adhesive contains a urethane polymer.

[0023] In the surface protective film of the embodiment of the present application, the urethane-based adhesive is formed from a urethane-based adhesive composition containing a base polymer (A) and a silicone-based compound (B).

[0024] In the surface protective film of the embodiment of the present application, the content ratio of the base polymer (A) in the urethane-based adhesive composition is preferably 50% by weight or more to 100% by weight or less, more preferably 70% by weight or more to 99% by weight or less, further preferably 80% by weight or more to 98% by weight or less, and particularly preferably 90% by weight or more to 97% by weight or less, in terms of solid content.

[0025] In the surface protective film of the embodiment of the present application, the content ratio of the base polymer (A) in the urethane-based adhesive composition is preferably 60% by weight or more to 99.9% by weight or less, more preferably 70% by weight or more to 99% by weight or less, further preferably 80% by weight or more to 98% by weight or less, and particularly preferably 90% by weight or more to 97% by weight or less, in terms of solid content. If the content ratio of the base polymer (A) in the urethane-based adhesive composition is within the above range in terms of solid content, the effects of the present application can be further exhibited.

[0026] The surface protective film of the embodiment of the present application can include any appropriate other member as long as it includes the adhesive layer composed of the urethane-based adhesive, without impairing the effects of the present application. Typically, the surface protective film of the embodiment of the present application includes a base material and the above adhesive layer. Also, as described later, on the surface of the adhesive layer on the side opposite to the base material, any appropriate release liner (sometimes also referred to as a release sheet, a separator) can be provided for protection before use or the like.

[0027] Figure 1 is a schematic cross-sectional view of a surface protective film of one embodiment of the present application. In Figure 1 , the surface protective film 10 is provided with a base material 1 and an adhesive layer 2. In Figure 1 , the base material 1 and the adhesive layer 2 are directly laminated.

[0028] In Figure 1 , on the surface of the adhesive layer 2 on the side opposite to the base material 1, any appropriate release liner (sometimes also referred to as a release sheet, a separator) can be provided for protection before use or the like (not shown). As the release liner, for example, a release liner in which the surface of a base material (liner base material) such as paper or a plastic film is treated with silicone; a release liner in which the surface of a base material (liner base material) such as paper or a plastic film is laminated with a polyolefin-based resin can be exemplified.

[0029] As the plastic film serving as the liner base material, for example, polyethylene film, polypropylene film, polybutylene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, and the like can be exemplified.

[0030] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, further preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0031] The thickness of the surface protective film of the embodiment of the present application can adopt any appropriate thickness within a range not impairing the effects of the present application. As such a thickness, 5 μm to 500 μm is preferable, 10 μm to 450 μm is more preferable, 15 μm to 400 μm is further preferable, and 20 μm to 300 μm is particularly preferable.

[0032] As the surface protective film of the embodiment of the present application, the average peeling force, i.e., the adhesive force (I), when the adhesive layer is attached to a glass plate and left for 30 minutes at an ambient temperature of 23°C, and the surface protective film is peeled from the glass plate at a peeling angle of 180 degrees and a peeling speed of 300 mm / minute, is preferably 5.0 gf / 25 mm or less, more preferably 4.0 gf / 25 mm or less, further preferably 3.5 gf / 25 mm or less, further preferably 3.0 gf / 25 mm or less, particularly preferably 2.5 gf / 25 mm or less, and most preferably 2.0 gf / 25 mm or less. From the viewpoint of being able to function as a surface protective film appropriately, the lower limit of the above-mentioned adhesive force (I) is preferably 0.3 gf / 25 mm or more in practice. If the above-mentioned adhesive force (I) is within the above-mentioned range, a surface protective film which can be moderately adhered to an adherend and peeled easily can be provided. If the above-mentioned adhesive force (I) is too large outside the above-mentioned range, for example, a surface protective film which is difficult to peel because of too high adhesive force to the adherend can be resulted. Note that the details of the measurement method of the above-mentioned adhesive force (I) will be described later.

[0033] In the surface protective film of the embodiment of the present application, the average peeling strength when the surface protective film is peeled from the glass plate at a peeling angle of 180 degrees and a peeling speed of 300 mm / minute after the adhesive layer is attached to the glass plate and left at an ambient temperature of 50°C for 1 day is set as the adhesive strength (II), and at this time, the degree of increase in the adhesive strength compared to the above-mentioned adhesive strength (I) is defined as the rate of increase in the adhesive strength to the glass plate over time, that is, the rate of increase in the adhesive strength to the glass plate over time defined by [(adhesive strength (II) / adhesive strength (I)] x 100 (%) is preferably less than 210%, more preferably 200% or less, further preferably 190% or less, further preferably 180% or less, further preferably 170% or less, further preferably 160% or less, further preferably 150% or less, further preferably 140% or less, particularly preferably 135% or less, and most preferably 130% or less. The lower limit of the above-mentioned rate of increase in the adhesive strength to the glass plate over time is preferably 100% or more. If the above-mentioned rate of increase in the adhesive strength to the glass plate over time is within the above-mentioned range, a surface protective film that is inhibited in the increase in the adhesive strength to the adherend over time, that is, a surface protective film that is moderately adhered to the adherend even after a lapse of time after attachment to the adherend and is easily peeled can be provided. If the above-mentioned rate of increase in the adhesive strength to the glass plate over time is excessively large outside the above-mentioned range, for example, the adhesive strength to the adherend can increase over time, and if a lapse of time occurs after attachment to the adherend, the adherend can be firmly adhered and become difficult to peel. Note that the details of the measurement method of the above-mentioned adhesive strength (II) will be described later.

[0034] In the surface protective film of the embodiment of the present application, the surface free energy of the adhesive layer surface with respect to diiodomethane is preferably 2.5 mJ / m 2 ~ 20.0 mJ / m 2 , more preferably 3.0 mJ / m 2 ~ 18.0 mJ / m 2 , further preferably 3.3 mJ / m 2 ~ 16.0 mJ / m 2 , particularly preferably 3.5 mJ / m 2 ~ 15.0 mJ / m 2 . By adjusting the surface free energy of the adhesive layer surface with respect to diiodomethane to be within the above-mentioned range, a surface protective film that exhibits both moderate easy peelability and low haze can be provided. If the surface free energy of the adhesive layer surface with respect to diiodomethane is excessively small, for example, the adhesive strength of the adhesive layer (for example, the adhesive strength (I) described in the present specification) can become excessively high, and the surface protective film can be difficult to peel. If the surface free energy of the adhesive layer surface with respect to diiodomethane is excessively large, for example, the haze can become high. Note that the details of the measurement method of the surface free energy of the adhesive layer surface with respect to diiodomethane will be described later.

[0035] The surface protective film of the embodiment of the present application preferably has a haze of 7.0% or less, more preferably 6.0% or less, further preferably 5.0% or less, further preferably 4.0% or less, further preferably 3.0% or less, particularly preferably 2.0% or less, most preferably 1.5% or less. The lower limit of the above-mentioned haze is preferably 0% or more. If the above-mentioned haze is within the above-mentioned range, the transparency of the surface protective film becomes high, and, for example, inspection and the like can be accurately performed in a state where the surface protective film is attached to the surface of an adherent such as an optical member or an electronic member. If the above-mentioned haze deviates from the above-mentioned range and becomes too large, for example, the transparency of the surface protective film can decrease, and, for example, the above-mentioned inspection can be hindered. Note that the details of the method for measuring the above-mentioned haze will be described later.

[0036] The surface protective film of the embodiment of the present application can be manufactured by any appropriate method. As such a manufacturing method, for example, any appropriate manufacturing method such as the following method can be employed.

[0037] (1) A method in which a solution or a hot melt of a material for forming an adhesive layer is applied to a substrate.

[0038] (2) A method in which a solution or a hot melt of a material for forming an adhesive layer is applied to a release liner, and the formed adhesive layer is transferred to a substrate.

[0039] (3) A method in which a material for forming an adhesive layer is extruded to a substrate, and the application is performed.

[0040] (4) A method in which a substrate and an adhesive layer are extruded in a double layer or a multiple layer.

[0041] (5) A method in which an adhesive layer is laminated to a substrate in a single layer, or a method in which an adhesive layer and a lamination layer are laminated to a substrate in a double layer.

[0042] (6) A method in which a material for forming an adhesive layer and a substrate such as a film or a lamination layer are laminated in a double layer or a multiple layer.

[0043] Note that, as the above-mentioned application method, any appropriate method can be employed. As such an application method, for example, a roll coater method, a comma coater method, a die coater method, a reverse coater method, a screen method, a gravure coater method, and the like can be used.

[0044] A-1. Adhesive Layer The adhesive layer is composed of a urethane-based adhesive. The urethane-based adhesive is formed from a urethane-based adhesive composition. That is, the adhesive layer is composed of a urethane-based adhesive formed from a urethane-based adhesive composition. Typically, a layer shape is formed by the urethane-based adhesive formed from the urethane-based adhesive composition, and becomes the adhesive layer.

[0045] The adhesive layer can be formed by any appropriate method. As such a method, for example, a method in which a urethane-based adhesive composition is applied to any appropriate substrate, heated / dried as necessary, cured as necessary, and an adhesive layer is formed on the substrate can be exemplified. The method of application, heating / drying conditions, curing conditions, and the like can be appropriately adopted from methods generally known as methods for forming an adhesive layer.

[0046] The thickness of the adhesive layer can be appropriately set in accordance with the purpose of the present application within a range that does not impair the effects of the present application. The thickness of the adhesive layer is typically 5 μm to 150 μm, preferably 10 μm to 120 μm, more preferably 20 μm to 110 μm, further preferably 30 μm to 100 μm, and particularly preferably 40 μm to 90 μm.

[0047] In the surface protective film of the embodiment of the present application, the urethane-based adhesive contains a urethane polymer. The urethane polymer in the urethane-based adhesive can be only one kind, or two or more kinds.

[0048] In the surface protective film of the embodiment of the present application, the content ratio of the urethane polymer in the urethane-based adhesive is preferably 60% by mass to 99.9% by mass, more preferably 70% by mass to 99.9% by mass, further preferably 80% by mass to 99.9% by mass, particularly preferably 85% by mass to 99.9% by mass, and most preferably 90% by mass to 99.9% by mass, in terms of solid content. If the content ratio of the urethane polymer in the urethane-based adhesive is within the above range in terms of solid content, the effects of the present application can be further exhibited.

[0049] In the surface protective film of the embodiment of the present application, the urethane polymer contained in the urethane-based adhesive is typically a prepolymer type urethane polymer. The prepolymer type urethane polymer can be only one kind, or two or more kinds.

[0050] Generally, as urethane polymers, "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 are known. The urethane prepolymer is obtained by reacting a polyol with an excess amount of a polyfunctional isocyanate compound, and has an isocyanate group at a molecular terminal. Therefore, in the surface protective film of the embodiment of the present application, the urethane polymer contained in the urethane-based adhesive, i.e., the prepolymer type urethane polymer is different from the one-shot type urethane polymer.

[0051] Here, the prepolymer type urethane polymer is obtained by reacting a urethane prepolymer contained in the urethane-based adhesive composition as the base polymer (A) with a polyfunctional isocyanate compound. Therefore, in the surface protective film of the embodiment of the present application, the urethane-based adhesive composition forming the urethane-based adhesive composition contains, for example, a urethane prepolymer as the base polymer (A), a polyfunctional isocyanate compound, and a silicone-based compound (B). Note that, as for the prepolymer type urethane polymer, it can be produced by any appropriate method within a range not impairing the effects of the present application, as long as the method used is in the urethane reaction of the urethane prepolymer as the base polymer (A) with the polyfunctional isocyanate compound.

[0052] <A-1-1. Urethane prepolymer as base polymer (A)> The urethane prepolymer as the base polymer (A) can be reacted with a polyfunctional isocyanate compound to become a prepolymer type urethane polymer.

[0053] The urethane prepolymer can be only one or two or more.

[0054] The number average molecular weight Mn of the urethane prepolymer is, for example, 3,000 to 1,000,000.

[0055] In the surface protective film of the embodiment of the present application, the urethane prepolymer is obtained by reacting a polyol with a polyfunctional isocyanate compound.

[0056] In the surface protective film of the embodiment of the present application, the polyol contains a polyester polyol (al) and a polyether polyol (a2). In particular, by containing not only the polyether polyol (a2) but also the polyester polyol (al), it is possible to provide a surface protective film that can exhibit both excellent anchorage and suppression of generation of a gum at the time of cutting. In particular, it is possible to effectively exhibit excellent anchorage.

[0057] The total content of the polyester polyol (al) and the polyether polyol (a2) in the polyol is preferably 50% by weight or more, more preferably 70% by weight or more, further preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably 98% by weight or more, from the viewpoint of further embodying the effects of the present application. The polyol is composed of the polyester polyol (al) and the polyether polyol (a2).

[0058] The polyester polyol (al) can be one kind or two or more kinds. The polyether polyol (a2) can be one kind or two or more kinds.

[0059] As the polyester polyol (al), a polyester polyol that is generally used for the production of urethane prepolymer can be appropriately used. As such a polyester polyol, for example, a polyester polyol obtained by reacting an acid component with a diol component can be exemplified. As the acid component, for example, terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid can be exemplified. As the diol component, for example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexanediol, 3-methyl-l,5-pentanediol, 3,3'-dihydroxymethylheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butyl ethyl pentanediol, glycerol, trimethylolpropane, pentaerythritol can be exemplified. As the polyester polyol, in addition, a polyester polyol obtained by ring-opening polymerization of a lactone such as polycaprolactone, poly(β-methyl-γ-valerolactone), polyvalerolactone, etc. can be exemplified.

[0060] As the molecular weight of the polyester polyol (al), a low molecular weight to a high molecular weight can be used. As the molecular weight of the polyester polyol (al), the number average molecular weight Mn is, for example, 100 to 100,000, preferably 100 to 10,000, more preferably 100 to 7,000, further preferably 500 to 5,000, and particularly preferably 1,000 to 4,000.

[0061] The content of the polyester polyol (al) in the polyol is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, further preferably 0.08% by weight or more, further preferably 0.1% by weight or more, particularly preferably 0.2% by weight or more, and most preferably 0.3% by weight or more. If the content of the polyester polyol (al) in the polyol is within the above range, a surface protective film that can exhibit excellent anchorage and suppress the generation of sludge at the time of cutting can be provided. In particular, excellent anchorage can be effectively exhibited.

[0062] As the polyether polyol (a2), a polyether polyol containing two or more groups selected from the group consisting of methylene and methine groups is exemplified, for example, a polyether polyol containing two groups selected from the group consisting of methylene and methine groups, a polyether polyol containing three or more groups selected from the group consisting of methylene and methine groups. The polyether polyol (a2) can be used in combination with a diol such as ethylene glycol, a polyamine such as ethylenediamine, or the like, as needed by replacing a part thereof.

[0063] As the polyether polyol containing two groups selected from the group consisting of methylene and methine groups, a polyethylene glycol, a polypropylene glycol is exemplified, for example.

[0064] As the polyether polyol containing three or more groups selected from the group consisting of methylene and methine groups, a polytetramethylene glycol is exemplified, for example.

[0065] As the molecular weight of the polyether polyol (a2), a low molecular weight to a high molecular weight can be used. As the molecular weight of the polyether polyol (a2), the number average molecular weight Mn is, for example, 100 to 100,000, preferably 100 to 10,000, more preferably 100 to 7,000, further preferably 500 to 5,000, particularly preferably 1,000 to 4,000.

[0066] The content ratio of the polyether polyol (a2) in the polyol is preferably 90.0% by mass or more to 99.99% by mass or less, more preferably 95.0% by mass or more to 99.95% by mass or less, further preferably 97.0% by mass or more to 99.92% by mass or less, further preferably 98.0% by mass or more to 99.9% by mass or less, particularly preferably 98.5% by mass or more to 99.8% by mass or less, most preferably 99.0% by mass or more to 99.7% by mass or less.

[0067] In the surface protective film of the embodiment of the present application, the polyether polyol (a2) contains a polyether polyol (a3) containing three or more groups selected from the group consisting of methylene and methine groups. By the polyether polyol (a2) containing the polyether polyol (a3) containing three or more groups selected from the group consisting of methylene and methine groups, a surface protective film capable of exhibiting both excellent anchoring force and suppression of generation of gum during cutting can be provided. In particular, generation of gum during cutting can be effectively suppressed.

[0068] From the aspect of further embodying the effect of the present application, the content ratio of the polyether polyol (a3) containing three or more groups selected from the group consisting of methylene and methine in the polyether polyol (a2) is preferably 40.0% by mass or more to 80.0% by mass or less, more preferably 42.5% by mass or more to 77.5% by mass or less, further preferably 45.0% by mass or more to 75.0% by mass or less, particularly preferably 47.5% by mass or more to 72.5% by mass or less, and most preferably 50% by mass or more to 70% by mass or less.

[0069] The polyfunctional isocyanate compound which is reacted with the polyol in order to obtain the urethane prepolymer can be only one or two or more.

[0070] As the polyfunctional isocyanate compound, any appropriate polyfunctional isocyanate compound which can be used for the preparation of the urethane prepolymer can be used. As such a polyfunctional isocyanate compound, for example, a polyfunctional aliphatic isocyanate compound, a polyfunctional alicyclic isocyanate compound, a polyfunctional aromatic isocyanate compound, a polyfunctional aromatic aliphatic isocyanate compound can be exemplified.

[0071] As the polyfunctional aliphatic isocyanate compound, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2- propylene diisocyanate, 1,3-butylene diisocyanate, 2,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate can be exemplified.

[0072] As the polyfunctional alicyclic isocyanate compound, for example, 3-isocyanatomethyl-3,5,5- trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4- cyclohexane diisocyanate, isophorone diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6- cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated toluene diisocyanate, hydrogenated tetramethyl xylene diisocyanate can be exemplified.

[0073] As the polyfunctional aromatic isocyanate compound, for example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanatotoluene, 1,3,5-triisocyanatobenzene, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4',4"-triphenylmethane triisocyanate, dimethoxybenzidine diisocyanate, xylylene diisocyanate can be listed.

[0074] As the polyfunctional aromatic aliphatic isocyanate compound, for example, ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylbenzene xylene diisocyanate, 1,3-tetramethylbenzene xylene diisocyanate can be listed.

[0075] As the polyfunctional isocyanate compound, trimethylolpropane adducts of various polyfunctional isocyanate compounds described above, biuret bodies obtained by reacting with water, trimers having isocyanurate rings, and the like can also be listed. In addition, they can be used in combination.

[0076] In order to produce the urethane prepolymer, it is preferable to use in an equivalent ratio in which the isocyanate group (NCO group) possessed by the polyfunctional isocyanate compound is in excess compared to the hydroxyl group (OH group) of the polyol. The equivalent ratio of the NCO group / OH group ([NCO] / [OH]) is preferably 1.01 to 5.0, more preferably 1.1 to 3.0, further preferably 1.1 to 2.0, particularly preferably 1.1 to 1.8, and most preferably 1.2 to 1.6.

[0077] In producing the urethane prepolymer, a catalyst can be used. As such a catalyst, any appropriate catalyst can be used within a range not impairing the effects of the present application. As such a catalyst, for example, tertiary amine-based catalysts, organometal-based catalysts can be listed. The catalyst can be only one kind, or two or more kinds.

[0078] As the tertiary amine-based catalyst, for example, triethylamine, triethylenediamine, 1,8-diazabicyclo(5,4,0)-undec-7-ene (DBU), and the like can be listed.

[0079] As the organometallic catalyst, for example, the following can be mentioned: bismuth octoate, bismuth neodecanoate, bismuth naphthenate, bismuth abietate, and the like; dibutyltin dilaurate (DBTDL), dioctyltin dilaurate (DOTDL), and the like; dibutyltitanium dichloride, tetrabutyl titanate, titanium butoxide, titanium butoxide acetylacetonate, and the like; iron 2-ethylhexanoate, iron acetylacetonate, and the like; cobalt benzoate, cobalt 2-ethylhexanoate, and the like; zinc octoate, zinc naphthenate, zinc 2-ethylhexanoate, and the like; and zirconium naphthenate, and the like.

[0080] In the case where a catalyst is used in the production of 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, further preferably 0.003 to 1.0% by weight, and particularly preferably 0.005 to 1.0% by weight, relative to the total amount of the polyol and the polyfunctional isocyanate compound.

[0081] In the case where a catalyst is used in the production of the urethane prepolymer, the reaction temperature is preferably lower than 100°C, and more preferably 85 to 95°C. If the reaction temperature is 100°C or higher, the reaction rate and the control of the crosslinked structure can become difficult.

[0082] In the production of the urethane prepolymer, a catalyst can not be used. In this case, the reaction temperature is preferably 100°C or higher, and more preferably 110°C or higher. Further, in the production of the urethane prepolymer without a catalyst, the reaction is preferably performed for 3 hours or longer.

[0083] As the method for producing the urethane prepolymer, any appropriate method can be employed without impairing the effects of the present application. As such a method, for example, the following can be mentioned: 1) a method in which the polyol, the catalyst, and the polyfunctional isocyanate compound are all charged into a reaction vessel; and 2) a method in which the polyol and the catalyst are charged into a reaction vessel, and the polyfunctional isocyanate compound is added dropwise. In the method of 2), the polyol and the polyfunctional isocyanate compound can be further added after the addition of the polyfunctional isocyanate compound is completed.

[0084] In the production of the urethane prepolymer, any appropriate solvent can be used. As such a solvent, for example, the following can be mentioned: methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone.

[0085] In the production of the urethane prepolymer, any other component can be used within a range not impairing the effects of the present application. As the other component, for example, an antioxidant, an ultraviolet absorber, a light stabilizer, a resin component, an adhesion promoter, a delayed crosslinking agent, an inorganic filler, an organic filler, a metal powder, a pigment, a foil, a softening agent, an anti-aging agent, a conductive agent, a surface lubricant, a leveling agent, an anticorrosive agent, a heat-resistant stabilizer, a polymerization inhibitor, a lubricant can be exemplified. The other component can be only one or two or more. Among the other components, the antioxidant, the ultraviolet absorber, the light stabilizer are preferable as one of the embodiments.

[0086] As the antioxidant, for example, a radical chain inhibitor, a peroxide decomposer can be exemplified. As the radical chain inhibitor, for example, a phenol-based antioxidant, an amine-based antioxidant can be exemplified. As the peroxide decomposer, for example, a sulfur-based antioxidant, a phosphorus-based antioxidant can be exemplified.

[0087] As the ultraviolet absorber, for example, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a salicylic acid-based ultraviolet absorber, an oxanilide-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, a triazine-based ultraviolet absorber can be exemplified.

[0088] As the light stabilizer, for example, a hindered amine-based light stabilizer can be exemplified.

[0089] <A-1-2. Polyfunctional isocyanate compound> The urethane-based adhesive composition contains a polyfunctional isocyanate compound as a representative. The polyfunctional isocyanate compound becomes a urethane polymer by reacting with the base polymer (A). In detail, the polyfunctional isocyanate compound can become a prepolymer type urethane polymer by reacting with the urethane prepolymer as the base polymer (A).

[0090] The polyfunctional isocyanate compound which reacts with the base polymer (A) can be only one or two or more.

[0091] As the polyfunctional isocyanate compound which reacts with the base polymer (A), any appropriate polyfunctional isocyanate compound which can be used for urethane reaction can be used. As such a polyfunctional isocyanate compound, for example, the above-described polyfunctional isocyanate compound which can be used for the production of the urethane prepolymer can be used.

[0092] In the case where the prepolymer-type urethane polymer is produced by reacting the polyfunctional isocyanate compound with the urethane prepolymer as the base polymer (A), the equivalent ratio of the isocyanate group (NCO group) possessed by the polyfunctional isocyanate compound to the hydroxyl group (OH group) possessed by the urethane prepolymer ([NCO] / [OH]) is preferably 2.00 or less, more preferably 1.70 or less, further preferably 0.60 to 1.70, further preferably 0.75 to 1.70, further preferably 0.90 to 1.70, further preferably 1.00 to 1.70, further preferably 1.10 to 1.65, particularly preferably 1.15 to 1.62, most preferably 1.15 to 1.60, further 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. If the equivalent ratio of the isocyanate group (NCO group) possessed by the polyfunctional isocyanate compound to the hydroxyl group (OH group) possessed by the urethane prepolymer ([NCO] / [OH]) is within the above range, the effects of the present application can be further exhibited.

[0093] In the case where the prepolymer-type urethane polymer is produced by reacting the polyfunctional isocyanate compound with the urethane prepolymer as the base polymer (A), the use ratio of the polyfunctional isocyanate compound with respect to 100 parts by weight of the urethane prepolymer is preferably 0.5 parts by weight to 15 parts by weight, more preferably 1.0 parts by weight to 10 parts by weight, further preferably 1.5 parts by weight to 8.0 parts by weight, particularly preferably 1.7 parts by weight to 6.0 parts by weight, most preferably 2.0 parts by weight to 5.0 parts by weight.

[0094] As for the production of the urethane polymer, any appropriate method can be employed without impairing the effects of the present application, as long as it is a method in which the urethane-based adhesive composition containing the base polymer (A) and the polyfunctional isocyanate compound is cured to form the urethane polymer. As such a method, for example, the following method can be cited: the urethane-based adhesive composition containing the base polymer (A) and the polyfunctional isocyanate compound is applied to any appropriate substrate, heated / dried as necessary, cured as necessary, an adhesive layer is formed on the substrate, and the urethane polymer is produced in the adhesive layer. The method of application, the heating / drying conditions, the curing conditions, and the like can be appropriately employed as the methods generally known as methods of forming an adhesive layer.

[0095] <A-1-3. Catalyst> In order to promote the reaction of the base polymer (A) with the polyfunctional isocyanate compound, and the like, the urethane-based adhesive composition can use a catalyst. As such a catalyst, any appropriate catalyst can be used within a range not impairing the effects of the present application. As such a catalyst, the above-mentioned catalysts that can be used for the production of the urethane prepolymer can be cited.

[0096] As the above-mentioned catalyst contained in the urethane-based adhesive composition, from the aspect of further manifesting the effects of the present application, an organometallic compound is preferred, and at least one selected from the group consisting of a zinc-based catalyst and a titanium-based catalyst is more preferred.

[0097] As the zinc-based catalyst, for example, zinc octoate, zinc naphthenate, zinc 2-ethylhexanoate can be cited.

[0098] As the titanium-based catalyst, for example, dibutyltitanium chloride, tetrabutyl titanate, titanium tributoxide chloride, titanium tetraacetylacetonate can be cited.

[0099] In the case where a catalyst is used in the production of the urethane polymer, the content of the catalyst in the urethane-based adhesive composition is preferably 0.0001 parts by mass to 1.0 parts by mass, more preferably 0.001 parts by mass to 1.0 parts by mass, further preferably 0.003 parts by mass to 1.0 parts by mass, particularly preferably 0.005 parts by mass to 1.0 parts by mass, relative to 100 parts by mass of the base polymer (A) in terms of solid content.

[0100] <A-1-4. Silicone-based compound (B)> The urethane-based adhesive composition contains a silicone-based compound (B). The silicone-based compound (B) can be only one or two or more.

[0101] The content of the silicone-based compound (B) in the urethane-based adhesive composition is preferably 0.001 parts by mass to 20 parts by mass, more preferably 0.005 parts by mass to 10 parts by mass, further preferably 0.01 parts by mass to 7 parts by mass, further preferably 0.01 parts by mass to 4 parts by mass, further preferably 0.01 parts by mass to 2 parts by mass, particularly preferably 0.01 parts by mass to 1 part by mass, most preferably 0.01 parts by mass to 0.80 parts by mass, relative to 100 parts by mass of the base polymer (A) in terms of solid content. If the content of the silicone-based compound (B) in the urethane-based adhesive composition is within the above-mentioned range, the effects of the present application can be further manifested. If the content of the silicone-based compound (B) in the urethane-based adhesive composition is too much, for example, the haze can become high.

[0102] The organosilicon compound (B) represents, for example, at least one selected from the group consisting of a reactive silicone oil and a non-reactive silicone oil. The proportion of at least one selected from the group consisting of a reactive silicone oil and a non-reactive silicone oil in the organosilicon compound (B) is preferably 50 to 100% by weight, more preferably 70 to 100% by weight, further preferably 90 to 100% by weight, particularly preferably 95 to 100% by weight, and most preferably 98 to 100% by weight.

[0103] As the organosilicon compound (B), in addition to at least one selected from the group consisting of a reactive silicone oil and a non-reactive silicone oil, any other appropriate organosilicon compound can be included within a range not impairing the effects of the present application.

[0104] As the reactive silicone oil, for example, a side chain type reactive silicone oil in which an organic group is bonded as a side chain to a Si atom of a siloxane bond, a two-terminal type reactive silicone oil in which an organic group is bonded to Si atoms at both terminals of the structure, a mono-terminal type reactive silicone oil in which an organic group is bonded to only one of the Si atoms at both terminals of the structure, a side chain two-terminal type reactive silicone oil in which an organic group is bonded as a side chain to a Si atom of a siloxane bond and an organic group is bonded to Si atoms at both terminals of the structure.

[0105] As the side chain type reactive silicone oil, for example, a side chain type reactive silicone oil of an amino-modified type, a side chain type reactive silicone oil of an epoxy-modified type, a side chain type reactive silicone oil of a methanol-modified type, a side chain type reactive silicone oil of a mercapto-modified type, a side chain type reactive silicone oil of a carboxyl-modified type, a side chain type reactive silicone oil of a methyl hydrogen silicone oil type. As their commercial products, for example, various silicone oils marketed as side chain type reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. can be cited.

[0106] As the two-terminal type reactive silicone oil, for example, a two-terminal type reactive silicone oil of an amino-modified type, a two-terminal type reactive silicone oil of an epoxy-modified type, a two-terminal type reactive silicone oil of a methanol-modified type, a two-terminal type reactive silicone oil of a methacrylic acid-modified type, a two-terminal type reactive silicone oil of a polyether-modified type, a two-terminal type reactive silicone oil of a mercapto-modified type, a two-terminal type reactive silicone oil of a carboxyl-modified type, a two-terminal type reactive silicone oil of a phenol-modified type, a two-terminal type reactive silicone oil of a silanol terminal type, a two-terminal type reactive silicone oil of an acrylic acid-modified type, a two-terminal type reactive silicone oil of a carboxylic anhydride-modified type. As their commercial products, for example, various silicone oils marketed as two-terminal type reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. can be cited.

[0107] As the single-end type reactive silicone oil, for example, a single-end type reactive silicone oil of a single-end reactive modification type, a single-end type reactive silicone oil of an average single-end carboxyl modification type, specifically, for example, a single-end type reactive silicone oil of a methanol modification type can be exemplified. As their commercial products, for example, various silicone oils sold as single-end type reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. can be exemplified.

[0108] As the side chain type non-reactive silicone oil, for example, a side chain type non-reactive silicone oil of a polyether modification type, a side chain type non-reactive silicone oil of an aralkyl modification type, a side chain type non-reactive silicone oil of a fluoroalkyl modification type, a side chain type non-reactive silicone oil of a long chain alkyl modification type, a side chain type non-reactive silicone oil of a higher fatty acid ester modification type, a side chain type non-reactive silicone oil containing a higher fatty acid type, a side chain type non-reactive silicone oil of a phenyl modification type can be exemplified. As their commercial products, for example, various silicone oils sold as side chain type non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. can be exemplified.

[0109] As the side chain type non-reactive silicone oil, for example, a side chain type non-reactive silicone oil of a polyether modification type, a side chain type non-reactive silicone oil of an aralkyl modification type, a side chain type non-reactive silicone oil of a fluoroalkyl modification type, a side chain type non-reactive silicone oil of a long chain alkyl modification type, a side chain type non-reactive silicone oil of a higher fatty acid ester modification type, a side chain type non-reactive silicone oil containing a higher fatty acid type, a side chain type non-reactive silicone oil of a phenyl modification type can be exemplified. As their commercial products, for example, various silicone oils sold as side chain type non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. can be exemplified.

[0110] As the side chain type non-reactive silicone oil, for example, a side chain type non-reactive silicone oil of a polyether modification type, a side chain type non-reactive silicone oil of an aralkyl modification type, a side chain type non-reactive silicone oil of a fluoroalkyl modification type, a side chain type non-reactive silicone oil of a long chain alkyl modification type, a side chain type non-reactive silicone oil of a higher fatty acid ester modification type, a side chain type non-reactive silicone oil containing a higher fatty acid type, a side chain type non-reactive silicone oil of a phenyl modification type can be exemplified. As their commercial products, for example, various silicone oils sold as side chain type non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. can be exemplified.

[0111] As the side chain type non-reactive silicone oil, for example, a side chain type non-reactive silicone oil of a polyether modification type, a side chain type non-reactive silicone oil of an aralkyl modification type, a side chain type non-reactive silicone oil of a fluoroalkyl modification type, a side chain type non-reactive silicone oil of a long chain alkyl modification type, a side chain type non-reactive silicone oil of a higher fatty acid ester modification type, a side chain type non-reactive silicone oil containing a higher fatty acid type, a side chain type non-reactive silicone oil of a phenyl modification type can be exemplified. As their commercial products, for example, various silicone oils sold as side chain type non-reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. can be exemplified.

[0112] As a preferable embodiment of the organosilicon compound (B), at least one selected from the group consisting of a reactive silicone oil having at least one selected from the group consisting of a polyether structure and a methanol structure and a non-reactive silicone oil having a polyether structure and an HLB value of 15 or less is contained. By the organosilicon compound (B) containing at least one selected from the group consisting of a reactive silicone oil having at least one selected from the group consisting of a polyether structure and a methanol structure and a non-reactive silicone oil having a polyether structure and an HLB value of 15 or less, a surface protective film which is moderately adhered to and easily peeled from an adherend and in which the adhesion to the adherend is inhibited from increasing over time, that is, which is moderately adhered to and easily peeled from the adherend even after a lapse of time after being attached to the adherend, can be provided.

[0113] As the reactive silicone oil having a polyether structure, for example, a polyether-modified type two-terminal reactive silicone oil can be cited.

[0114] As the polyether-modified type two-terminal reactive silicone oil, for example, "X-22-4952", "X-22-4272", "KF-6123" manufactured by Shin-Etsu Chemical Co., Ltd. can be cited.

[0115] As the reactive silicone oil having a methanol structure, for example, a methanol-modified type side chain reactive silicone oil, a methanol-modified type two-terminal reactive silicone oil, and a methanol-modified type single-terminal reactive silicone oil can be cited.

[0116] As the methanol-modified type side chain reactive silicone oil, for example, "X-22-4039", "X-22-4015" manufactured by Shin-Etsu Chemical Co., Ltd. can be cited.

[0117] As the methanol-modified type two-terminal reactive silicone oil, for example, "KF-6000", "KF-6001", "KF-6002", "KF-6003" manufactured by Shin-Etsu Chemical Co., Ltd. can be cited.

[0118] As the methanol-modified type single-terminal reactive silicone oil, for example, "X-22-170BX", "X-22-170DX" manufactured by Shin-Etsu Chemical Co., Ltd. can be cited.

[0119] The non-reactive silicone oil having a polyether structure and an HLB value of 15 or less is only required to be a non-reactive silicone oil having a polyether structure and an HLB value of 15 or less selected from non-reactive silicone oils having a polyether structure.

[0120] As the non-reactive silicone oil having a polyether structure, for example, a polyether-modified type side chain non-reactive silicone oil and a polyether-modified type two-terminal non-reactive silicone oil can be cited.

[0121] As commercially available products of the side chain type non-reactive silicone oil of the polyether-modified type, 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", "X-22-2516" manufactured by Shin-Etsu Chemical Co., Ltd. can be listed.

[0122] As the non-reactive silicone oil of the polyether-modified type and having an HLB value of 15 or less, for example, among the above-mentioned commercially available products, "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), "KF-642" (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), "X-22-2516" (HLB = 1) can be listed.

[0123] As commercially available products of the two-terminal type non-reactive silicone oil of the polyether-modified type, for example, "KF-6004" manufactured by Shin-Etsu Chemical Co., Ltd. can be listed.

[0124] As the non-reactive silicone oil of the two-terminal type and having an HLB value of 15 or less, for example, among the above-mentioned commercially available products, "KF-6004" (HLB = 9) can be listed.

[0125] <A-1-5. Other Ingredients> In the urethane-based adhesive composition, any other appropriate component can be included within a range not impairing the effects of the present application. As such other components, for example, ion compounds, fatty acid esters, solvents, cross-linking accelerators, silane coupling agents, antioxidants, ultraviolet absorbers, light stabilizers, resin components, tackifiers, retardation cross-linking agents, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), chain transfer agents, plasticizers, softening agents, anti-aging agents, electric conductive agents, foils, surface lubricants, leveling agents, anticorrosive agents, heat-resistant stabilizers, polymerization inhibitors, lubricants can be listed. The other components can be only one or two or more.

[0126] A-2. Substrate The substrate can be only one layer or two or more layers. The substrate can be a stretched substrate.

[0127] The thickness of the substrate is preferably 4 μm to 450 μm, more preferably 8 μm to 400 μm, further preferably 12 μm to 350 μm, and particularly preferably 16 μm to 250 μm.

[0128] The surface of the substrate to which the adhesive layer is not attached can be subjected to a release treatment, for example, by adding a fatty acid amide, a polyethylene imine, a long-chain alkyl additive, or the like to the substrate, or a coating layer formed of any appropriate release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent can be provided.

[0129] As the material of the substrate, any appropriate material can be used depending on the purpose. For example, plastics, paper, metal films, nonwoven fabrics, and the like can be listed. Plastics are preferred. That is, the substrate is preferably a plastic film. The substrate can be composed of one material or two or more materials. For example, it can be composed of two or more plastics.

[0130] As the above-mentioned plastics, for example, polyester-based resins, polyamide-based resins, polyolefin-based resins, and the like can be listed. As the polyester-based resins, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and the like can be listed.

[0131] The substrate can contain any appropriate additive as needed. As the additive that the substrate can contain, for example, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, pigments, and the like can be listed. The kind, number, and amount of the additive that the substrate can contain can be appropriately set depending on the purpose. In particular, in the case where the material of the substrate is plastics, it is preferred to contain several of the above-mentioned additives for the purpose of preventing deterioration and the like. From the viewpoint of improving weather resistance and the like, as the additive, antioxidants, ultraviolet absorbers, light stabilizers, and fillers are particularly preferred.

[0132] The surface protective film of the embodiment of the present application is typically attached to the exposed surface of the optical member or the electronic member in the manufacturing process of the optical member or the electronic member in order to prevent scratching of the surface of the optical member or the electronic member at the time of processing, assembling, inspection, transportation, and the like, and is preferably used for surface protection of the optical member or the electronic member. The optical member of the present application has the surface protective film of the present application attached thereto. The electronic member of the present application has the surface protective film of the present application attached thereto.

[0133] Example Hereinafter, the present application will be specifically described by way of examples, but the present application is not limited at all by these examples. Note that the test and evaluation methods in the examples and the like are described below. Note that in the case where "parts" is described, "parts by weight" is meant unless otherwise specified, and in the case where "%" is described, "%" by weight" is meant unless otherwise specified.

[0134] Measurement of adhesion to glass plate (I) (after 30 minutes of placement at 23°C) The surface protective film from which the release liner was peeled was cut into a width of 25 mm x a length of 140 mm, and was pressure-bonded to the surface of a glass plate (soda-lime glass, manufactured by Matsushita Seiren Co., Ltd.) using a 2-kg hand roller for one reciprocation, to thereby produce a sample, in an environment of 23°C and 50% RH.

[0135] After the sample was left to stand for 30 minutes in an environment of 23°C, the sample was set in a tensile tester, and the tensile test was started. The conditions of the tensile test were set to be in an environment of 23°C and 50% RH, at a peeling angle of 180 degrees, and at a peeling speed (tensile speed) of 300 mm / minute. The peeling force (load) at the time of peeling the surface protective film from the glass plate was measured, and the average peeling force (average load) at that time was set as the adhesion to glass plate (I) (sometimes referred to simply as the adhesion (I)). As the tensile tester, a product with the trade name "Autograph AG-Xplus HS 6000 mm / min high speed mode (AG-50NXplus)" manufactured by Shimadzu Corporation was used.

[0136] Measurement of adhesion to glass plate (II) (after 1 day of placement at 50°C) The surface protective film from which the release liner was peeled was cut into a width of 25 mm x a length of 140 mm, and was pressure-bonded to the surface of a glass plate (soda-lime glass, manufactured by Matsushita Seiren Co., Ltd.) using a 2-kg hand roller for one reciprocation, to thereby produce a sample, in an environment of 23°C and 50% RH.

[0137] ​After the sample was left at an ambient temperature of 50°C for 1 day, the sample was set to a tensile tester, and the tensile test was started. The conditions of the tensile test were set to an ambient temperature of 23°C, 50% RH, a peeling angle of 180 degrees, and a peeling speed (tensile speed) of 300 mm / min. The peeling force (load) at the time of peeling the surface protective film from the glass plate was measured, and the average peeling force (average load) at that time was set as the adhesion to the glass plate (II) (sometimes referred to simply as the adhesion (II)). As the tensile tester, a product of Shimadzu Corporation, trade name "Autograph AG-X plus HS 6000 mm / min high speed mode (AG-50NX plus)" was used.

[0138] <Calculation of the rate of increase in the adhesion to the glass plate over time> Calculated from the formula of [adhesion (II) / adhesion (I)] x 100 (%).

[0139] <Measurement of the surface free energy of the adhesive layer surface with respect to methylene iodide> The surface protective film from which the release liner was peeled was cut to a size of 50 mm x 100 mm, and the adhesive layer surface was set as the upper surface, and was fixed to a contact angle meter (Kosugi Interface Science, Inc., model "CA-X"). 2.0 μL of water was added dropwise to the adhesive layer surface, and the contact angle was measured. Next, in the same order, 2.0 μL of methylene iodide was added dropwise to the adhesive layer surface, and the contact angle was measured. From the values of the contact angles of the two kinds of liquids, the surface free energy of the adhesive layer surface with respect to methylene iodide was calculated using the Owens-Wendt method.

[0140] <Measurement of the haze> The surface protective film from which the release liner was peeled was cut to a size of 50 mm x 50 mm, and was measured using "HM-150N" of Murakami Color Research Laboratory Co., Ltd. in an environment of 23°C, 50% RH.

[0141] <Evaluation of the anchorage strength> The surface protective film was cut to a size of 50 mm x 50 mm, and an evaluation sample was prepared. When the release liner was peeled from the evaluation sample, and the adhesive layer side was rubbed with a finger from the end surface, the case where the adhesive layer was peeled from the substrate was evaluated as x, the case where the adhesive layer was peeled from the substrate when rubbed strongly was evaluated as Δ, and the case where the adhesive layer was not peeled from the substrate was evaluated as O.

[0142] <Cutability> The blade of a cutter was cut into the center of the adhesive layer side of the surface protective film (width 25 mm x length 140 mm) from which the release liner was peeled at an angle of 90 degrees, and was cut off by 1 cm. The case where the gum residue was confirmed by visual observation was set as G (good), and the case where the gum residue was not confirmed was set as B (better).

[0143] [Production Example 1] Production of urethane prepolymer A Into an experimental apparatus equipped with a 1 L round bottom separable flask, a separable cap, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and stirring blades, was put polytetramethylene glycol (product name "PTMG 3000", manufactured by Mitsubishi Chemical Corporation): 260 g, polypropylene glycol (product name "SANNIX GP-1500", manufactured by So-ya Chemical Industry Co., Ltd.): 173 g, polyester polyol (product name "Kuraray Polyol P-2010", manufactured by Kuraray Co., Ltd.): 3 g, ethyl acetate (manufactured by TOSOH Corporation) as a solvent: 150 g, bismuth octoate (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.05 g, while stirring, under nitrogen substitution at normal temperature for 1 hour. Then, under nitrogen flow, hexamethylene diisocyanate (product name "HDI", manufactured by TOSOH Corporation): 15 g was put while stirring, the solution temperature in the experimental apparatus was controlled to be 90 ± 2°C using a water bath, and polymerization was performed for 4 hours, obtaining a solution of urethane prepolymer A. Note that, during the polymerization, in order to prevent a decrease in stirring performance due to temperature control and viscosity increase during polymerization, ethyl acetate was appropriately added dropwise. The total amount of the added ethyl acetate was 300 g. The solid content concentration of the solution of urethane prepolymer A was 50% by weight.

[0144] [Production Example 2] Production of urethane prepolymer B To an experimental apparatus equipped with a 1 L round bottom separable flask, a separable cap, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum sealer, a stirring rod, stirring blades, was charged polypropylene glycol (product name "SANNIX PP-2000", manufactured by Sanyo Chemical Industries, Ltd.): 347 g, polyester polyol (product name "Kuraray Polyol P-2010", manufactured by Kuraray Co., Ltd.): 47 g, toluene (manufactured by TOSOH) as a solvent: 110 g, bismuth octoate (manufactured by Japan Chemical Industries, Ltd.) as a catalyst: 0.041 g, and nitrogen substitution was performed for 1 hour at ordinary temperature while stirring. Then, under nitrogen flow, hexamethylene diisocyanate (product name "HDI", manufactured by TOSOH) : 33.5 g was charged while stirring, the solution temperature in the experimental apparatus was controlled to 90 ± 2°C using a water bath, and after 4 hours, polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Industries, Ltd.): 44 g was charged, the solution temperature in the experimental apparatus was controlled to 90 ± 2°C using a water bath, and after 2 hours, hexamethylene diisocyanate (product name "HDI", manufactured by TOSOH) : 25.4 g was charged, the solution temperature in the experimental apparatus was controlled to 90 ± 2°C using a water bath, and after 2 hours, a solution of urethane prepolymer C was obtained. Note that during polymerization, toluene was appropriately added dropwise in order to prevent a decrease in stirring properties due to temperature control and viscosity increase during polymerization. The total amount of toluene added dropwise was 380 g. The solid content concentration of the solution of urethane prepolymer C was 50% by weight.

[0145] [Manufacture Example 3]: Manufacture of Urethane Prepolymer C A 1L round-bottom separable flask, a separable cap, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stir bar, and stirring blades were used to add 260g of polytetramethylene glycol (PTMG3000, manufactured by Mitsubishi Chemical Corporation), 173g of polypropylene glycol (SANNIX GP-1500, manufactured by Sanyo Chemical Corporation), and 150g of ethyl acetate (TOSOH Corporation) as solvent. While stirring, 0.05g of bismuth octoate (Nippon Kagaku S.A., manufactured by Nippon Kagaku S.A.) as catalyst was added, and nitrogen replacement was carried out at room temperature for 1 hour. Then, under nitrogen inflow, 17g of hexamethylene diisocyanate (HDI, manufactured by TOSOH Corporation) was added while stirring. The solution temperature in the experimental apparatus was controlled at 90±2℃ using a water bath and maintained for 4 hours to carry out polymerization, yielding a solution of urethane prepolymer C. It should be noted that during polymerization, ethyl acetate was added dropwise to prevent a decrease in agitation caused by temperature control and viscosity increases. The total amount of ethyl acetate added was 300g. The solids concentration of the carbamate prepolymer C solution was 50% by weight.

[0146] [Example 1] A urethane-based adhesive composition (1) was obtained by diluting 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 Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of KF-354L (manufactured by Shin-Etsu Chemical Co., Ltd.) as an organosilicon compound, 0.50 parts by weight of Irganox 1010 (manufactured by BASF Co., Ltd.) as an antioxidant, and 0.20 parts by weight of Nikka Octhix Zinc 18% (manufactured by Nippon Chemical Industry Co., Ltd.) as a catalyst with ethyl acetate.

[0147] A urethane-based adhesive composition (1) was applied to a polyester resin substrate (trade name "T100-75S", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) to a thickness of 75 μm after drying. The substrate was cured and dried at a drying temperature of 150°C for 3 minutes to create an adhesive layer (1). Next, a 25 μm thick release liner made of polyester resin (trade name "MRF25", thickness 25 μm, manufactured by Mitsubishi Chemical Corporation) with one side treated with silicone was bonded to the surface of the adhesive layer (1) to obtain a surface protective film (1). The film was then aged at room temperature for 5 days for various evaluations.

[0148] The results are shown in Tables 1 and 2.

[0149] [Example 2] urethane prepolymer A: 100 parts by weight, a polyfunctional isocyanate compound (CORONATE HX (C / HX), manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent: 4.0 parts by weight, KF-640 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound: 0.10 parts by weight, Irganox 1010 (manufactured by BASF) as an antioxidant: 0.50 parts by weight, Nikka Octhix Zinc 18% (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.20 parts by weight, were diluted with ethyl acetate so that the solid content of the whole would be 50% by weight, to obtain a urethane-based adhesive composition (2).

[0150] Example 1 was repeated except that the urethane-based adhesive composition (2) was used instead of the urethane-based adhesive composition (1), to obtain an adhesive layer (2) and a surface protective film (2). Aging was performed at normal temperature for 5 days, and various evaluations were performed.

[0151] The results are shown in Tables 1 and 2.

[0152] [Example 3] urethane prepolymer A: 100 parts by weight, a polyfunctional isocyanate compound (CORONATE HX (C / HX), manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent: 4.0 parts by weight, X-22-4515 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound: 0.10 parts by weight, Irganox 1010 (manufactured by BASF) as an antioxidant: 0.50 parts by weight, Nikka Octhix Zinc 18% (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.20 parts by weight, were diluted with ethyl acetate so that the solid content of the whole would be 50% by weight, to obtain a urethane-based adhesive composition (3).

[0153] Example 1 was repeated except that the urethane-based adhesive composition (3) was used instead of the urethane-based adhesive composition (1), to obtain an adhesive layer (3) and a surface protective film (3). Aging was performed at normal temperature for 5 days, and various evaluations were performed.

[0154] The results are shown in Tables 1 and 2.

[0155] [Example 4] The urethane-based adhesive composition (4) was obtained by diluting urethane prepolymer A: 100 parts by weight, a polyfunctional isocyanate compound (CORONATE HX (C / HX), manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent: 4.0 parts by weight, KF-6001 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound: 0.10 part by weight, Irganox 1010 (manufactured by BASF) as an antioxidant: 0.50 part by weight, Nikka Octhix Zinc 18% (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.20 part by weight, with ethyl acetate so that the solid content of the whole becomes 50% by weight.

[0156] The urethane-based adhesive composition (4) was used instead of the urethane-based adhesive composition (1), and otherwise, the same as in Example 1 was performed to obtain an adhesive layer (4) and a surface protective film (4). Aging was performed for 5 days at normal temperature, and various evaluations were performed.

[0157] The results are shown in Tables 1 and 2.

[0158] [Example 5] The urethane-based adhesive composition (5) was obtained by diluting urethane prepolymer A: 100 parts by weight, a polyfunctional isocyanate compound (CORONATE HX (C / HX), manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent: 4.0 parts by weight, KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound: 0.10 part by weight, Irganox 1010 (manufactured by BASF) as an antioxidant: 0.50 part by weight, Nikka Octhix Zinc 18% (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.20 part by weight, with ethyl acetate so that the solid content of the whole becomes 50% by weight.

[0159] The urethane-based adhesive composition (5) was used instead of the urethane-based adhesive composition (1), and otherwise, the same as in Example 1 was performed to obtain an adhesive layer (5) and a surface protective film (5). Aging was performed for 5 days at normal temperature, and various evaluations were performed.

[0160] The results are shown in Tables 1 and 2.

[0161] [Example 6] The urethane-based adhesive composition (6) was obtained by diluting, with ethyl acetate, so that the solid content of the whole would be 50% by weight, 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 Industry Co., Ltd.) as a crosslinking agent, 0.10 part by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 0.50 part by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 part by weight of ORGATIX TC-401 (titanium tetraacetylacetonate, manufactured by Matsumoto Fine Chemical Co., Ltd.) as a catalyst.

[0162] Using the urethane-based adhesive composition (6) in place of the urethane-based adhesive composition (1), the same procedure as in Example 1 was carried out to obtain an adhesive layer (6) and a surface protective film (6). Aging was carried out at room temperature for 5 days, and various evaluations were carried out.

[0163] The results are shown in Tables 1 and 2.

[0164] [Example 7] The urethane-based adhesive composition (7) was obtained by diluting, with ethyl acetate, so that the solid content of the whole would be 50% by weight, 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 Industry Co., Ltd.) as a crosslinking agent, 0.10 part by weight of KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound, 0.50 part by weight of Irganox 1010 (manufactured by BASF) as an antioxidant, and 0.20 part by weight of NACEM Iron (III) (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst.

[0165] Using the urethane-based adhesive composition (7) in place of the urethane-based adhesive composition (1), the same procedure as in Example 1 was carried out to obtain an adhesive layer (7) and a surface protective film (7). Aging was carried out at room temperature for 5 days, and various evaluations were carried out.

[0166] The results are shown in Tables 1 and 2.

[0167] [Example 8] urethane prepolymer A: 100 parts by weight, a polyfunctional isocyanate compound (CORONATE HX (C / HX), manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent: 4.0 parts by weight, KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound: 0.50 parts by weight, Irganox 1010 (manufactured by BASF) as an antioxidant: 0.50 parts by weight, Nikka Octhix Zinc 18% (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.20 parts by weight, were diluted with ethyl acetate so that the solid content of the whole would be 50% by weight, to obtain a urethane-based adhesive composition (8).

[0168] Using the urethane-based adhesive composition (8) in place of the urethane-based adhesive composition (1), the same as in Example 1 was carried out, to obtain an adhesive layer (8), a surface protective film (8). Aging was carried out for 5 days at normal temperature, and various evaluations were carried out.

[0169] The results are shown in Tables 1 and 2.

[0170] [Comparative Example 1] urethane prepolymer B: 100 parts by weight, a polyfunctional isocyanate compound (CORONATE HX (C / HX), manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent: 4.0 parts by weight, KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound: 0.10 parts by weight, Irganox 1010 (manufactured by BASF) as an antioxidant: 0.50 parts by weight, Nikka Octhix Zinc 18% (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.20 parts by weight, were diluted with ethyl acetate so that the solid content of the whole would be 50% by weight, to obtain a urethane-based adhesive composition (C1).

[0171] Using the urethane-based adhesive composition (C1) in place of the urethane-based adhesive composition (1), the same as in Example 1 was carried out, to obtain an adhesive layer (C1), a surface protective film (C1). Aging was carried out for 5 days at normal temperature, and various evaluations were carried out.

[0172] The results are shown in Tables 1 and 2.

[0173] [Comparative Example 2] The urethane prepolymer C: 100 parts by weight, a polyfunctional isocyanate compound (CORONATE HX (C / HX), manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent: 4.0 parts by weight, KF-615A (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicone-based compound: 0.10 parts by weight, Irganox 1010 (manufactured by BASF) as an antioxidant: 0.50 parts by weight, Nikka Octhix Zinc 18% (manufactured by Japan Chemical Industry Co., Ltd.) as a catalyst: 0.20 parts by weight were diluted with ethyl acetate so that the solid content would be 50% by weight, to obtain a urethane-based adhesive composition (C2).

[0174] Using the urethane-based adhesive composition (C2) instead of the urethane-based adhesive composition (1), the same as in Example 1 was performed, to obtain an adhesive layer (C2), a surface protective film (C2). Aging was performed at normal temperature for 5 days, and various evaluations were performed.

[0175] The results are shown in Tables 1 and 2. [Examples 9 to 16] For each of the surface protective films (1) to (8) obtained in Examples 1 to 8, the release liner was peeled off, and the adhesive layer side was attached to a polarizing plate (manufactured by DOW CORNING TORAY CO., LTD., trade name "TEG1465DUHC") as an optical member, to obtain an optical member to which the surface protective film was attached.

[0176] [Examples 17 to 24] For each of the surface protective films (1) to (8) obtained in Examples 1 to 8, the release liner was peeled off, and the adhesive layer side was attached to a conductive film (manufactured by DOW CORNING TORAY CO., LTD., trade name "ELECRYSTA V270L-TFMP") as an electronic member, to obtain an electronic member to which the surface protective film was attached.

[0177] Industrial applicability The surface protective film of the present application can be used for any appropriate use. It is preferable that the surface protective film of the present application is preferably used in the field of optical members, electronic members.

Claims

1. A surface protective film comprising an adhesive layer composed of a urethane-based adhesive, the urethane-based adhesive contains a urethane polymer, the urethane-based adhesive is formed from a urethane-based adhesive composition, the urethane-based adhesive composition contains a base polymer A and a silicone-based compound B, the base polymer A is a urethane prepolymer obtained by reacting a polyol with a polyfunctional isocyanate compound, the polyol contains a polyester polyol al and a polyether polyol a2, the polyether polyol a2 contains a polyol a3 containing three or more groups selected from the group consisting of methylene and methine.

2. The surface protective film according to claim 1, wherein the polyester polyol al in the polyol is contained in a proportion of 0.01 to 10.0% by weight.

3. The surface protective film according to claim 1, wherein the urethane-based adhesive composition contains a catalyst which is at least one selected from the group consisting of a zinc-based catalyst and a titanium-based catalyst.

4. The surface protective film according to claim 1, wherein the average peeling force when the surface protective film is peeled from a glass plate at a peeling angle of 180 degrees and a peeling speed of 300 mm / min after the adhesive layer is attached to the glass plate and left for 30 minutes at an ambient temperature of 23°C is set as the adhesive force I, and the average peeling force when the surface protective film is peeled from the glass plate at a peeling angle of 180 degrees and a peeling speed of 300 mm / min after the adhesive layer is attached to the glass plate and left for 1 day at an ambient temperature of 50°C is set as the adhesive force II, and at this time, the rate of increase in the adhesive force to the glass plate with time defined by [adhesive force II / adhesive force I] x 100% is less than 210%.

5. The surface protective film according to claim 1, wherein the silicone-based compound B contains at least one selected from the group consisting of a reactive silicone oil having at least one selected from the group consisting of a polyether structure and a methanol structure, and a non-reactive silicone oil having a polyether structure and an HLB value of 15 or less.

6. The surface protective film according to claim 1, wherein The surface free energy of the adhesive layer surface for diiodomethane is 2.5 mJ / m 2 ~ 20.0 mJ / m 2 .

7. The surface protective film according to claim 1, wherein the content of the silicone-based compound B is 0.01 to 0.48 parts by weight with respect to 100 parts by weight of the base polymer A.

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

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

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