Surface protective film

Abstract

Provided is a surface protective film which includes an adhesive layer and which is not susceptible to damage to an adherend such as an optical member or an electronic member even when the surface protective film is peeled from the adherend at a high speed. 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 comprises a base polymer (A) and a silicone-based compound (B), the urethane polymer is a prepolymer-type urethane polymer, the base polymer (A) is a urethane prepolymer, and the silicone-based compound (B) is a silicone-based compound. The silicone compound (B) contains at least one compound selected from the group consisting of silicone compounds having a polyether structure and silicone compounds having a methanol structure, and the weight-average molecular weight (Mw) of the silicone compound (B) is 2000 or more.

Description

Technical Field

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

[0002] In the manufacturing process of optical and electronic components, to prevent surface scratches during processing, assembly, inspection, and transportation, a surface protective film is usually applied to the exposed surface of the optical or electronic component. This surface protective film is then peeled off from the optical or electronic component at a point when surface protection is no longer required (Patent Document 1).

[0003] When peeling the protective film from an optical or electronic component, it is required that the film can be peeled off smoothly only at the interface between the protective film and the optical or electronic component, i.e., with light peelability.

[0004] As a method to impart light peelability to the surface protective film, a technique of adding fluorinated compounds or organosilicon compounds to the adhesive composition forming the adhesive layer has been reported in the past (Patent Documents 2 and 3).

[0005] Optical and electronic components are typically expensive and easily damaged. Therefore, it is crucial that the protective film applied to the exposed surfaces of optical and electronic components is peeled off without damaging them. In particular, if the protective film is peeled off at high speed to increase productivity, it may damage the optical and electronic components.

[0006] Existing technical 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 of the Invention

[0007] The problem that the invention aims to solve The technical problem of the present invention is to provide a surface protective film, which includes an adhesive layer, such that even if the surface protective film is peeled off from an object such as an optical component or electronic component at high speed, the object is not easily damaged.

[0008] Solution for solving the problem [1] The surface protective film of the present invention comprises an adhesive layer made of a urethane-based adhesive, the urethane-based adhesive comprising a urethane polymer, the urethane-based adhesive being formed from a urethane-based adhesive composition comprising a base polymer (A) and an organosilicon compound (B), the urethane polymer being a prepolymer type urethane polymer, the base polymer (A) being a urethane prepolymer, and the organosilicon compound (B) comprising at least one selected from the group consisting of organosilicon compounds having a polyether structure and organosilicon compounds having a methanol structure, the organosilicon compound (B) having a weight-average molecular weight Mw of 2000 or more.

[0009] [2] Alternatively, according to the surface protective film described in [1] above, the urethane-based adhesive composition comprises a polyfunctional isocyanate compound, wherein the equivalent ratio ([NCO] / [OH]) of the NCO group of the polyfunctional isocyanate compound to the OH group of the urethane prepolymer is 1.50 or less.

[0010] [3] According to the surface protective film described in [1] or [2] above, after the adhesive layer is pasted onto the glass plate and placed at an ambient temperature of 23°C for 30 minutes, the average peel force when the surface protective film is peeled off from the glass plate at a peel angle of 180 degrees and a peel speed of 1800 mm / min is defined as the high-speed adhesive force (I). After the adhesive layer is pasted onto the glass plate and placed at an ambient temperature of 50°C for 1 day, the average peel force when the surface protective film is peeled off from the glass plate at a peel angle of 180 degrees and a peel speed of 1800 mm / min is defined as the high-speed adhesive force (II). At this time, the rate of increase of the high-speed adhesive force on the glass plate over time, defined by [high-speed adhesive force (II) / high-speed adhesive force (I)] × 100 (%), is less than 200%.

[0011] [4] Alternatively, it may be a surface protective film according to any one of [1] to [3] above, wherein the organosilicon compound (B) comprises an organosilicon compound having a polyether structure.

[0012] [5] Alternatively, the surface protective film according to [4] above, wherein the organosilicon compound having a polyether structure is at least one selected from the group consisting of reactive silicone oil and non-reactive silicone oil with an HLB value of 15 or less.

[0013] [6] Alternatively, it may be a surface protective film according to any one of [1] to [5] above, wherein the weight-average molecular weight Mw of the organosilicon compound (B) is 10,000 or more.

[0014] [7] The optical components of the embodiments of the present invention include a surface protective film as described in any one of [1] to [6] above.

[0015] [8] The electronic components of the embodiments of the present invention include a surface protective film as described in any one of [1] to [6] above.

[0016] Invention Effects According to the present invention, a surface protective film comprising an adhesive layer is provided, which is less likely to cause damage to the adhered object even when the surface protective film is peeled off from the adhered object at high speed. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of a surface protective film according to one embodiment of the present invention. Detailed Implementation

[0018] In the presence of the term "weight" in this specification, it may also be replaced with "mass," which is the SI unit commonly used to express weight.

[0019] In this specification, the expression "(meth)acrylic acid" refers to "acrylic acid and / or methacrylic acid", the expression "(meth)acrylate" refers to "acrylate and / or methacrylate", the expression "(meth)allyl" refers to "allyl and / or methylallyl", and the expression "(meth)acrylaldehyde" refers to "acrylaldehyde and / or methacrolein".

[0020] 《A. Surface Protective Film》 The surface protective film of embodiments of the present invention includes an adhesive layer composed of a urethane-based adhesive. In the surface protective film of embodiments of the present invention, the urethane-based adhesive comprises a urethane polymer.

[0021] In the surface protective film of the embodiments of the present invention, the urethane adhesive is formed from a urethane adhesive composition comprising a base polymer (A) and an organosilicon compound (B).

[0022] In the surface protective film of the embodiments of the present invention, the total content of the base polymer (A) and the organosilicon compound (B) in the urethane adhesive composition is preferably 50% to 100% by weight, more preferably 70% to 99% by weight, further preferably 80% to 98% by weight, and particularly preferably 90% to 97% by weight in terms of solid content.

[0023] In the surface protective film of the embodiments of the present invention, the content of the base polymer (A) in the urethane adhesive composition, converted to solids, is preferably 60% to 99.9% by weight, more preferably 70% to 99% by weight, further preferably 80% to 98% by weight, and particularly preferably 90% to 97% by weight. If the content of the base polymer (A) in the urethane adhesive composition, converted to solids, is within the above range, the effects of the present invention can be further demonstrated.

[0024] The surface protective film of embodiments of the present invention may include any suitable other components without impairing the effects of the present invention, as long as it comprises an adhesive layer made of a urethane-based adhesive. For example, the surface protective film of embodiments of the present invention comprises a substrate and the aforementioned adhesive layer. Furthermore, as described later, any suitable release liner (sometimes also called a release sheet or diaphragm) may be provided on the surface of the adhesive layer opposite to the substrate for protection before use, etc.

[0025] Figure 1 This is a schematic cross-sectional view of a surface protective film according to one embodiment of the present invention. Figure 1 In this process, the surface protective film 10 comprises a substrate 1 and an adhesive layer 2. Figure 1 In this process, substrate 1 and adhesive layer 2 are directly laminated.

[0026] exist Figure 1 In this adhesive layer 2, on the surface opposite to the substrate 1, an arbitrary and suitable release liner (sometimes called a release sheet or diaphragm) (not shown) may be provided for protection before use. Examples of release liners include: release liners whose surfaces (liner substrates) such as paper or plastic film are treated with silicone; and release liners whose surfaces (liner substrates) are laminated with polyolefin resin.

[0027] Examples of plastic films used as liner substrates include: polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

[0028] 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.

[0029] The thickness of the surface protective film in embodiments of the present invention can be any suitable thickness without impairing the effects of the present invention. Preferably, the thickness is 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.

[0030] Regarding the surface protective film according to embodiments of the present invention, after the adhesive layer is adhered to a glass plate and placed at an ambient temperature of 23°C for 30 minutes, the average peel force, i.e., the high-speed adhesive force (I), when the surface protective film is peeled from the glass plate at a peel angle of 180 degrees and a peel speed of 1800 mm / min is preferably 10.0 gf / 25 mm or less, more preferably 8.0 gf / 25 mm or less, further preferably 6.0 gf / 25 mm or less, even more preferably 5.5 gf / 25 mm or less, particularly preferably 5.0 gf / 25 mm or less, and most preferably 4.5 gf / 25 mm or less. From the viewpoint of being able to function appropriately as a surface protective film, practically speaking, the lower limit value of the above-mentioned high-speed adhesive force (I) is preferably 0.5 gf / 25 mm or more. If the above-mentioned high-speed adhesive force (I) is within the above range, a surface protective film can be provided that does not easily cause damage to the adhered object even when the surface protective film adhered to the exposed surface of the adhered object is peeled at high speed. If the high-speed adhesive force (I) deviates excessively from the above range, the adhered object may be damaged, for example, when the protective film on the exposed surface of the adhered object is peeled off at high speed. It should be noted that details of the method for measuring the high-speed adhesive force (I) will be described later.

[0031] Regarding the surface protective film in the embodiments of the present invention, after the adhesive layer is adhered to a glass plate and placed at an ambient temperature of 50°C for 1 day, the average peel force when the surface protective film is peeled from the glass plate at a peel angle of 180 degrees and a peel speed of 1800 mm / min is defined as the high-speed adhesive force (II). The increase in adhesive force compared to the aforementioned high-speed adhesive force (I), defined as the rate of increase in high-speed adhesive force over time for the glass plate by [high-speed adhesive force (II) / high-speed adhesive force (I)] × 100 (%), is preferably 300% or less, more preferably 250% or less, further preferably 200% or less, further preferably 180% or less, further preferably 170% or less, further preferably 160% or less, further preferably 150% or less, particularly preferably 140% or less, and most preferably 130% or less. The lower limit of the aforementioned rate of increase in adhesive force over time for the glass plate is preferably 100% or more. If the rate of increase in high-speed adhesive force over time to the glass plate is within the aforementioned range, the rate of increase in high-speed adhesive force to the adhered object over time is suppressed, and the adhered object is less likely to break even if the protective film adhered to the exposed surface of the adhered object is peeled off at high speed after a period of time. If the rate of increase in high-speed adhesive force over time to the glass plate deviates excessively from the aforementioned range, the adhesive force to the adhered object will increase over time, and for example, the adhered object may break when the protective film adhered to the exposed surface of the adhered object is peeled off at high speed after a period of time. It should be noted that the details of the method for measuring the high-speed adhesive force (II) will be described later.

[0032] The surface protective film of the embodiments of the present invention can be manufactured by any suitable method. For example, it can be manufactured according to any suitable method, such as the following method.

[0033] (1) A method of applying a solution or hot melt liquid of an adhesive layer forming material onto a substrate.

[0034] (2) A method of applying a solution or hot melt of the adhesive layer forming material to a release liner and transferring the formed adhesive layer to a substrate.

[0035] (3) A method of extruding the adhesive layer forming material onto the substrate to form a coating.

[0036] (4) A method of extruding the substrate and adhesive layer in a double or multi-layer manner.

[0037] (5) A method of laminating an adhesive layer onto a substrate in a single layer or a method of laminating an adhesive layer and a laminate together onto a substrate in a double layer.

[0038] (6) A method for double-layer or multi-layer lamination of substrate forming materials such as adhesive layers, films, and laminates.

[0039] It should be noted that any suitable method can be used as described above for coating. Examples of such coating methods include: roller coating, comma coating, die coating, reverse coating, screen printing, gravure coating, etc.

[0040] 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, which is formed from a urethane-based adhesive composition. For example, the urethane-based adhesive, formed from a urethane-based adhesive composition, constitutes a layer shape, thus becoming an adhesive layer.

[0041] The adhesive layer can be formed by any suitable method. One such method is, for example, applying a urethane-based adhesive composition to any suitable substrate, heating / drying as needed, and curing it as needed to form an adhesive layer on the substrate. The application method, heating / drying conditions, curing conditions, etc., can be suitably adopted from methods commonly known for forming adhesive layers.

[0042] The thickness of the adhesive layer can be appropriately set according to the purpose of the invention without impairing the effects of the invention. 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.

[0043] In the surface protective film of embodiments of the present invention, the urethane-based adhesive comprises a urethane polymer. The urethane polymer in the urethane-based adhesive may be only one type, or it may be two or more types.

[0044] In the surface protective film of the embodiments of the present invention, the content of urethane polymer in the urethane-based adhesive, converted from solid components, is preferably 60% to 99.9% by weight, more preferably 70% to 99.9% by weight, further preferably 80% to 99.9% by weight, particularly preferably 85% to 99.9% by weight, and most preferably 90% to 99.9% by weight. If the content of urethane polymer in the urethane-based adhesive, converted from solid components, falls within the above range, the effects of the present invention can be further demonstrated.

[0045] In the surface protective film of the embodiments of the present invention, the urethane polymer contained in the urethane-based adhesive is, generally speaking, a prepolymer-type urethane polymer. The prepolymer-type urethane polymer may be only one type, or it may be two or more types.

[0046] Generally, as urethane polymers, "prepolymer-type urethane polymers" manufactured by reacting urethane prepolymers with polyfunctional isocyanate compounds and "one-step urethane polymers" manufactured by directly reacting polyols with polyfunctional isocyanate compounds without using urethane prepolymers are known. Uraffinate prepolymers, in particular, are obtained by reacting polyols with an excess of polyfunctional isocyanate compounds and have isocyanate groups at the molecular ends. Therefore, in the surface protective film of the embodiments of the present invention, the urethane polymer contained in the urethane-based adhesive, i.e., the prepolymer-type urethane polymer, differs from the one-step urethane polymer.

[0047] Here, the prepolymer type urethane polymer is obtained by reacting the urethane prepolymer (A), which is contained in the urethane-based adhesive composition, with a polyfunctional isocyanate compound. Therefore, in the surface protective film of the embodiments of the present invention, the urethane-based adhesive composition forming the urethane-based adhesive typically includes the urethane prepolymer (A), the polyfunctional isocyanate compound, and the organosilicon compound (B). It should be noted that, regarding the prepolymer type urethane polymer, any suitable method can be used to prepare it without impairing the effects of the present invention, as long as the method used in the reaction of the urethane prepolymer (A) with the polyfunctional isocyanate compound isocyanate.

[0048] <A-1-1. Carbamate prepolymers as the base polymer (A)> The urethane prepolymers (A) that form the base polymer can react with polyfunctional isocyanate compounds to form prepolymer-type urethane polymers.

[0049] The urethane prepolymer can be one type or two or more types.

[0050] The urethane prepolymer is preferably a polyurethane polyol, more preferably obtained by reacting the 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.

[0051] The polyol comprises at least one selected from the group consisting of polyester polyols and polyether polyols. Specifically, the polyol consists of at least one selected from the group consisting of polyester polyols and polyether polyols. Polyester polyols may be only one type or may consist of two or more types. Polyether polyols may be only one type or may consist of two or more types.

[0052] As the polyester polyol, a polyester polyol commonly used in the preparation of urethane prepolymers can be appropriately used. Examples of such polyester polyols include those obtained by reacting an acidic component with a diol component. Examples of acidic components include: terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of diol components include: ethylene glycol, propylene glycol, diethylene glycol, butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentanediol, butylethylpentanediol, glycerol, trimethylolpropane, and pentaerythritol. Other examples of polyester polyols include those obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerol), and polyvalerol.

[0053] The molecular weight of the polyester polyol can range from low to high. The number average molecular weight Mn of the polyester polyol is, for example, 100 to 100,000, preferably 100 to 10,000.

[0054] As the polyether polyol, a polyether polyol commonly used in the preparation of urethane prepolymers can be appropriately used. Examples of such polyether polyols include, for instance, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and other polyether polyols containing two or more functional groups; more specifically, polyether polyols containing at least one group selected from the group consisting of methylene and methine groups can be included. A portion of the polyether polyol can be replaced with diols such as ethylene glycol, polyamines such as ethylenediamine, etc., as needed.

[0055] The molecular weight of the polyether polyol can range from low to high. The number average molecular weight Mn of the polyether polyol is, for example, 100 to 100,000, preferably 100 to 10,000.

[0056] One embodiment of the polyol is embodiment (A), which includes both polyester polyol and polyether polyol. In embodiment (A), the polyol is typically composed of both polyester polyol and polyether polyol.

[0057] In embodiment (A), the proportion of polyester polyol in the polyol is preferably 0.1% to 99.9% by weight, more preferably 0.1% to 80% by weight, further preferably 0.2% to 60% by weight, even more preferably 0.2% to 40% by weight, particularly preferably 0.3% to 30% by weight, and most preferably 0.3% to 20% by weight.

[0058] In embodiment (A), the polyether polyol content in the polyol is preferably 0.1% to 99.9% by weight, more preferably 20% to 99.9% by weight, further preferably 40% to 99.8% by weight, even more preferably 60% to 99.8% by weight, particularly preferably 70% to 99.7% by weight, and most preferably 80% to 99.7% by weight.

[0059] In embodiment (A), the polyether polyol is, for example, a polyether polyol containing at least two groups selected from the group consisting of methylene and methine. For instance, it may be a polyether polyol containing only two groups selected from the group consisting of methylene and methine, or it may be composed of a polyether polyol containing at least two groups selected from the group consisting of methylene and methine and a polyether polyol containing at least three groups selected from the group consisting of methylene and methine. Examples of polyether polyols containing at least two groups selected from the group consisting of methylene and methine include polyethylene glycol and polypropylene glycol. Examples of polyether polyols containing at least three groups selected from the group consisting of methylene and methine include polytetramethylene glycol.

[0060] Another embodiment of the polyol is embodiment (B), which contains a polyether polyol but does not contain a polyester polyol. In embodiment (B), the polyol is, in particular, composed of a polyether polyol.

[0061] In embodiment (B), the polyether polyol is, for example, a polyether polyol containing at least two groups selected from the group consisting of methylene and methine. For instance, it may be a polyether polyol containing only two groups selected from the group consisting of methylene and methine, or it may be composed of a polyether polyol containing at least two groups selected from the group consisting of methylene and methine and a polyether polyol containing at least three groups selected from the group consisting of methylene and methine. Examples of polyether polyols containing at least two groups selected from the group consisting of methylene and methine include polyethylene glycol and polypropylene glycol. Examples of polyether polyols containing at least three groups selected from the group consisting of methylene and methine include polytetramethylene glycol.

[0062] The polyfunctional isocyanate compound reacted with the polyol to obtain the urethane prepolymer can be one or more.

[0063] As a polyfunctional isocyanate compound, any suitable polyfunctional isocyanate compound that can be used to prepare urethane prepolymers can be used. Examples of such polyfunctional isocyanate compounds include: polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanate compounds, polyfunctional aromatic isocyanate compounds, and polyfunctional aromatic aliphatic isocyanate compounds.

[0064] 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, dodecamethyl diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0065] Examples of polyfunctional alicyclic isocyanate compounds include: 3-isocyanomethyl-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(isocyanomethyl)cyclohexane, 1,4-bis(isocyanomethyl)cyclohexane, hydrogenated diphenylmethane diisocyanate, hydrogenated phenyl dimethyl diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated tetramethylphenyl dimethyl diisocyanate.

[0066] Examples of polyfunctional aromatic isocyanate compounds include: 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-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, dimethoxybenzidine diisocyanate, and phenyl dimethyl diisocyanate.

[0067] 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-tetramethylbenzene dimethyl diisocyanate, and 1,3-tetramethylbenzene dimethyl diisocyanate.

[0068] Examples of polyfunctional isocyanate compounds include trimethylolpropane adducts, biuret forms formed by the reaction with water, and trimers containing isocyanurate rings, as described above. Furthermore, they can be used in combination.

[0069] To prepare the urethane prepolymer, it is preferable to use an equivalence ratio in which the isocyanate group (NCO group) of the polyfunctional isocyanate compound is in excess compared to the hydroxyl group (OH group) of the polyol. Such an equivalence ratio of NCO group to 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.

[0070] A catalyst can be used in the preparation of urethane prepolymers. Any suitable catalyst can be used without impairing the effects of the present invention. Examples of such catalysts include tertiary amine catalysts and organometallic catalysts. There may be only one catalyst or two or more catalysts.

[0071] Examples of tertiary amine catalysts include triethylamine, triethylenediamine, and 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU).

[0072] Examples of organometallic catalysts include: bismuth-based catalysts such as bismuth octanoate, 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 tetraacetylacetone titanium; iron-based catalysts such as ferric 2-ethylhexanoate and ferric acetylacetone; cobalt-based catalysts such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based catalysts such as zinc octanoate, zinc naphthenate, and zinc 2-ethylhexanoate; and zirconium-based catalysts such as zirconium naphthenate.

[0073] When a catalyst is used in the preparation of the urethane prepolymer, the amount of catalyst used relative to the total amount of polyol (a) and polyfunctional isocyanate compound is preferably 0.0001 wt% to 1.0 wt%, more preferably 0.001 wt% to 1.0 wt%, further preferably 0.003 wt% to 1.0 wt%, and particularly preferably 0.005 wt% to 1.0 wt%.

[0074] When a catalyst is used in the preparation of urethane prepolymers, the reaction temperature is preferably below 100°C, more preferably 85°C to 95°C. If the reaction temperature is above 100°C, it may become difficult to control the reaction rate and the crosslinking structure.

[0075] When preparing urethane prepolymers, a catalyst may not be used. In this case, the reaction temperature is preferably 100°C or higher, more preferably 110°C or higher. Furthermore, when preparing urethane prepolymers without a catalyst, the reaction time is preferably 3 hours or more.

[0076] As a method for preparing urethane prepolymers, any suitable method can be employed without impairing the effects of the present invention. Examples of such methods include: 1) a method of loading the polyol, catalyst, and polyfunctional isocyanate compound into a reaction vessel in their entirety; and 2) a method of loading the polyol and catalyst into a reaction vessel and then adding the polyfunctional isocyanate compound dropwise. In method 2), it is also possible to further add the polyol and polyfunctional isocyanate compound after the dropwise addition of the polyfunctional isocyanate compound.

[0077] In preparing urethane prepolymers, any suitable solvent can be used. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone.

[0078] In preparing the urethane prepolymer, any suitable other components may be used without impairing the effects of the present invention. Examples of such other components include: antioxidants, ultraviolet absorbers, light stabilizers, resin components, tackifiers, delayed crosslinking agents, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, and lubricants. There may be only one or more of these other components. Among these other components, antioxidants, ultraviolet absorbers, and light stabilizers are preferred embodiments.

[0079] Examples of antioxidants include: free radical chain inhibitors and peroxide decomposers. Examples of free radical chain inhibitors include: phenolic antioxidants and amine antioxidants. Examples of peroxide decomposers include: sulfur-based antioxidants and phosphorus-based antioxidants.

[0080] Examples of UV absorbers include: benzophenone-based UV absorbers, benzotriazole-based UV absorbers, salicylic acid-based UV absorbers, oxaloyl aniline-based UV absorbers, cyanoacrylate-based UV absorbers, and triazine-based UV absorbers.

[0081] Examples of light stabilizers include hindered amine light stabilizers.

[0082] <A-1-2. Polyfunctional Isocyanate Compounds> The urethane-based adhesive composition typically comprises a polyfunctional isocyanate compound. The polyfunctional isocyanate compound reacts with a base polymer (A) to become a urethane polymer. More specifically, the polyfunctional isocyanate compound can react with a urethane prepolymer, which is the base polymer (A), to become a prepolymer-type urethane polymer.

[0083] The polyfunctional isocyanate compound that reacts with the base polymer (A) can be just one or more.

[0084] As the polyfunctional isocyanate compound that reacts with the base polymer (A), any suitable polyfunctional isocyanate compound that can be used for urethane esterification reactions can be used. For example, the polyfunctional isocyanate compound described above that can be used to prepare urethane prepolymers can be used as such a polyfunctional isocyanate compound.

[0085] When preparing a prepolymer-type urethane polymer by reacting a polyfunctional isocyanate compound with a urethane prepolymer as a base polymer (A), the equivalent ratio (〔NCO〕 / 〔OH〕) of the isocyanate group (NCO group) of the polyfunctional isocyanate compound to the hydroxyl group (OH group) of the urethane prepolymer is preferably 3.50 or less, more preferably 2.50 or less, further preferably 2.00 or less, further preferably 1.70 or less, 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 preferably 1.20 to 1.60, or 1.25 to 1.60, or 1.30 to 1.60, or 1.35 to 1.60, or 1.40 to 1.60, or 1.45 to 1.60. If the equivalent ratio ([NCO] / [OH]) of the isocyanate group (NCO group) in the polyfunctional isocyanate compound to the hydroxyl group (OH group) in the urethane prepolymer is within the above-mentioned range, the effects of the present invention can be further demonstrated, and the generation of glue residue during the cutting of the obtained surface protective film can be suppressed. If glue residue is generated in this way, problems such as easy process defects may occur.

[0086] When preparing a prepolymer-type urethane polymer by reacting a polyfunctional isocyanate compound with a urethane prepolymer as the base polymer (A), the proportion of the polyfunctional isocyanate compound to 100 parts by weight of the urethane prepolymer is preferably 0.5 to 15 parts by weight, more preferably 1.0 to 10 parts by weight, even more preferably 1.5 to 8.0 parts by weight, particularly preferably 1.7 to 6.0 parts by weight, and most preferably 2.0 to 5.0 parts by weight.

[0087] Regarding the preparation of urethane polymers, any suitable method can be employed without impairing the effects of the present invention, as long as it involves curing a urethane-based adhesive composition containing a base polymer (A) and a polyfunctional isocyanate compound to form the urethane polymer. Examples of such methods include: applying the urethane-based adhesive composition containing the base polymer (A) and the polyfunctional isocyanate compound onto any suitable substrate, heating / drying as needed, curing as needed, forming an adhesive layer on the substrate, and preparing the polymer in this adhesive layer. The coating method, heating / drying conditions, curing conditions, etc., can be appropriately employed using methods commonly known for forming adhesive layers.

[0088] <A-1-3. Catalyst> To facilitate the reaction between the base polymer (A) and the polyfunctional isocyanate compound, a catalyst can be used in the urethane-based adhesive composition. Any suitable catalyst can be used without impairing the effects of the present invention. Examples of such catalysts include those described above that can be used to prepare urethane prepolymers.

[0089] When a catalyst is used in the preparation of the urethane polymer, the content of the catalyst in the urethane-based adhesive composition, converted to solids, is preferably 0.0001 to 1.0 parts by weight relative to 100 parts by weight of the base polymer (A), more preferably 0.001 to 1.0 parts by weight, even more preferably 0.003 to 1.0 parts by weight, and particularly preferably 0.005 to 1.0 parts by weight.

[0090] <A-1-4. Organosilicon compounds (B)> The urethane-based adhesive composition contains an organosilicon compound (B). The organosilicon compound (B) may be one or more.

[0091] The content of the organosilicon compound (B) in the urethane-based adhesive composition, relative to 100 parts by weight of the base polymer (A) in solids form, is preferably 0.001 to 20 parts by weight, more preferably 0.005 to 10 parts by weight, further preferably 0.01 to 7 parts by weight, even more preferably 0.01 to 4 parts by weight, even more preferably 0.01 to 2 parts by weight, particularly preferably 0.01 to 1 part by weight, and most preferably 0.01 to 0.80 parts by weight. If the content of the organosilicon compound (B) in the urethane-based adhesive composition is within the above range, the effects of the present invention are further demonstrated.

[0092] The organosilicon compound (B) typically comprises at least one selected from the group consisting of reactive and non-reactive silicone oils. The proportion of at least one selected from the group consisting of reactive and non-reactive silicone oils 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.

[0093] As an organosilicon compound (B), in addition to comprising at least one selected from the group consisting of reactive and non-reactive silicone oils, any other suitable organosilicon compound may be included to the extent that it does not impair the effects of the present invention.

[0094] Examples of reactive silicone oils include: side-chain reactive silicone oils in which organic groups are bonded as side chains to Si atoms that provide siloxane bonds; two-terminal reactive silicone oils in which organic groups are bonded to Si atoms at both ends of the structure; single-terminal reactive silicone oils in which only one of the Si atoms at both ends of the structure is bonded with an organic group; and two-terminal reactive silicone oils in which organic groups are bonded as side chains to Si atoms that provide siloxane bonds and organic groups are bonded to Si atoms at both ends of the structure.

[0095] Examples of side-chain reactive silicone oils include, for example, amino-modified, epoxy-modified, methanol-modified, mercapto-modified, carboxyl-modified, and methylhydrosilicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0096] Examples of two-terminated reactive silicone oils include, for example, amino-modified two-terminated reactive silicone oils, epoxy-modified two-terminated reactive silicone oils, methanol-modified two-terminated reactive silicone oils, methacrylic acid-modified two-terminated reactive silicone oils, polyether-modified two-terminated reactive silicone oils, mercapto-modified two-terminated reactive silicone oils, carboxyl-modified two-terminated reactive silicone oils, phenol-modified two-terminated reactive silicone oils, silanol-terminated two-terminated reactive silicone oils, acrylic acid-modified two-terminated reactive silicone oils, and carboxylic anhydride-modified two-terminated reactive silicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0097] Examples of single-terminal reactive silicone oils include: single-terminal reactive modified silicone oils, and single-terminal reactive silicone oils modified with an average single-terminal carboxyl group. More specifically, methanol-modified single-terminal reactive silicone oils are an example. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0098] Examples of reactive silicone oils with two-terminal side chains include: reactive silicone oils modified with amino / methoxy groups on the side chains, and reactive silicone oils modified with epoxy groups. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd.

[0099] Examples of non-reactive silicone oils include: side-chain type non-reactive silicone oils in which organic groups are bonded to the Si atoms that provide siloxane bonds as side chains, and two-terminal type non-reactive silicone oils in which organic groups are bonded to the Si atoms located at both ends of the structure.

[0100] Examples of side-chain non-reactive silicone oils include: polyether-modified side-chain non-reactive silicone oils, aralkyl-modified side-chain non-reactive silicone oils, fluoroalkyl-modified side-chain non-reactive silicone oils, long-chain alkyl-modified side-chain non-reactive silicone oils, higher fatty acid ester-modified side-chain non-reactive silicone oils, side-chain non-reactive silicone oils containing higher fatty acids, and phenyl-modified side-chain non-reactive silicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0101] Examples of two-terminated non-reactive silicone oils include, for example, polyether-modified two-terminated non-reactive silicone oils. Commercially available examples include various silicone oils manufactured by Shin-Etsu Chemical Co., Ltd., which are commercially available as two-terminated non-reactive silicone oils.

[0102] In a preferred embodiment of the organosilicon compound (B), it comprises at least one selected from the group consisting of organosilicon compounds having a polyether structure and organosilicon compounds having a methanol structure. The content of at least one selected from the group consisting of organosilicon compounds having a polyether structure and organosilicon compounds having a methanol structure 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] In a more preferred embodiment of the organosilicon compound (B), an organosilicon compound having a polyether structure is included. The proportion of the organosilicon compound having a polyether structure 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. If the organosilicon compound (B) includes an organosilicon compound having a polyether structure, a surface protective film is provided that makes the adhered object less prone to damage even when the surface protective film is peeled off at high speed from the exposed surface of the adhered object.

[0104] Examples of organosilicon compounds with polyether structures include: the above-mentioned polyether-modified two-terminal reactive silicone oils, polyether-modified side-chain non-reactive silicone oils, and polyether-modified two-terminal non-reactive silicone oils.

[0105] Commercially available products of polyether-modified two-terminal reactive silicone oils include, for example, Shin-Etsu Chemical Co., Ltd.'s "X-22-4952", "X-22-4272", and "KF-6123".

[0106] Commercially available products of polyether-modified side-chain non-reactive silicone oils include, for example, Shin-Etsu Chemical Industry Co., Ltd.'s "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".

[0107] Commercially available products that are two-terminated non-reactive silicone oils modified with polyethers include, for example, "KF-6004" manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0108] Examples of organosilicon compounds with a methanol structure include: the methanol-modified side-chain reactive silicone oil, the methanol-modified two-terminal reactive silicone oil, and the methanol-modified single-terminal reactive silicone oil.

[0109] Commercially available products that are methanol-modified side-chain reactive silicone oils include, for example, Shin-Etsu Chemical Co., Ltd.'s "X-22-4039" and "X-22-4015".

[0110] Commercially available products of methanol-modified two-terminal reactive silicone oils include, for example, Shin-Etsu Chemical Co., Ltd.'s "KF-6000", "KF-6001", "KF-6002" and "KF-6003".

[0111] Commercially available single-terminal reactive silicone oils of the methanol-modified type include, for example, Shin-Etsu Chemical Co., Ltd.'s "X-22-170BX" and "X-22-170DX".

[0112] As a preferred embodiment of the organosilicon compound (B), it is an organosilicon compound with a weight-average molecular weight Mw of 2000 or more. The weight-average molecular weight Mw of such an organosilicon compound is preferably 3000 to 1000000, more preferably 4000 to 500000, even more preferably 5000 to 100000, even more preferably 8000 to 50000, even more preferably 10000 to 50000, even more preferably 12000 to 50000, even more preferably 14000 to 50000, even more preferably 16000 to 40000, even more preferably 18000 to 40000, even more preferably 20000 to 40000. If the weight-average molecular weight Mw of the organosilicon compound (B) is within the above range, it can provide a surface protective film that further suppresses the increase in high-speed adhesion to the adhered object over time, and is less likely to cause damage to the adhered object even after a period of time when the surface protective film is peeled off at high speed after being applied to the exposed surface of the adhered object.

[0113] The organosilicon compound (B) having a polyether structure is preferably selected from at least one of the group consisting of reactive silicone oils and non-reactive silicone oils with an HLB value of 15 or less. If the organosilicon compound (B) is an organosilicon compound having a polyether structure and is selected from at least one of the group consisting of reactive silicone oils and non-reactive silicone oils with an HLB value of 15 or less, it can provide a surface protective film that is less likely to cause damage to the adhered object even when the surface protective film is peeled off at high speed on the exposed surface of the adhered object. In addition, it can provide a surface protective film that further suppresses the increase in high-speed adhesion to the adhered object over time, and is less likely to cause damage to the adhered object even when the surface protective film is peeled off at high speed after a period of time after being applied to the exposed surface of the adhered object.

[0114] In the organosilicon compound (B) described above, for example, from the perspective of providing a surface protective film that is less likely to cause damage to the adhered object even when the surface protective film is peeled off at high speed on the exposed surface of the adhered object, and further suppressing the increase in high-speed adhesion to the adhered object over time, and further preventing damage to the adhered object even when the surface protective film is peeled off at high speed after a period of time after the surface protective film is applied to the adhered object, a non-reactive silicone oil having a polyether structure and an HLB value of 15 or less is more preferred.

[0115] Organosilicon compounds that are organosilicon compounds with a polyether structure and are reactive silicone oils include, for example, the above-mentioned polyether-modified two-terminal reactive silicone oils.

[0116] Commercially available polyether-modified two-terminal reactive silicone oils include, for example, Shin-Etsu Chemical Co., Ltd.'s "X-22-4952", "X-22-4272", and "KF-6123".

[0117] Examples of non-reactive silicone oils that are organosilicon compounds with a polyether structure and an HLB value of 15 or less include: the aforementioned polyether-modified side-chain type non-reactive silicone oil with an HLB value of 15 or less, and the aforementioned polyether-modified two-terminal type non-reactive silicone oil with an HLB value of 15 or less.

[0118] Examples of non-reactive silicone oils with HLB values ​​of 15 or less, which are side-chain modified polyether-type silicone oils, include: Shin-Etsu Chemical Industry Co., Ltd.'s "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" (HLB=15). 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).

[0119] For example, non-reactive silicone oils with HLB values ​​of 15 or less, such as the two-terminated non-reactive silicone oils modified with polyether, include "KF-6004" (HLB=9) manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0120] <A-1-5. Other Components> The urethane-based adhesive composition may contain any suitable other components without impairing the effects of the present invention. Examples of such other components include, for instance: ionic compounds, fatty acid esters, solvents, crosslinking accelerators, silane coupling agents, antioxidants, ultraviolet absorbers, light stabilizers, resin components, tackifiers, delayed crosslinking agents, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), chain transfer agents, plasticizers, softeners, anti-aging agents, conductive agents, foils, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, and lubricants. Other components may be one or more.

[0121] A-2. Substrate The substrate can be a single layer or two or more layers. The substrate can be a stretched substrate.

[0122] The thickness of the substrate is preferably 4μm to 450μm, more preferably 8μm to 400μm, even more preferably 12μm to 350μm, and particularly preferably 16μm to 250μm.

[0123] For the purpose of forming easily rewound coils, release treatment can be performed on the side of the substrate without an adhesive layer, for example, by adding fatty acid amides, polyethylene imine, long-chain alkyl additives, etc., or by applying a coating formed by any suitable release agent such as organosilicon, long-chain alkyl, or fluorine.

[0124] The substrate material can be any suitable material depending on the application. Examples include: plastic, paper, metal film, non-woven fabric, etc. Plastic is 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.

[0125] Examples of the aforementioned plastics include polyester resins, polyamide resins, and polyolefin resins. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0126] The substrate can contain any suitable additives as needed. Examples of additives that can be included in the substrate include: antioxidants, UV absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, quantity, and amount of additives that the substrate can contain can be appropriately determined according to the purpose. In particular, when the substrate material is plastic, it is preferable to contain several of the above-mentioned additives for the purpose of preventing deterioration. From the viewpoint of improving weather resistance, antioxidants, UV absorbers, light stabilizers, and fillers are particularly preferred as additives.

[0127] 《B. Application》 The surface protective film of the present invention, in embodiments thereof, can be applied to the exposed surface of optical components or electronic components during the manufacturing process of optical components or electronic components to prevent scratches on the surface of the optical components or electronic components during processing, assembly, inspection, transportation, etc., and is preferably used for surface protection of optical components or electronic components. The optical components of the present invention are coated with the surface protective film of the present invention. The electronic components of the present invention are coated with the surface protective film of the present invention.

[0128] Example The present invention will now be specifically described through examples, but the present invention is not limited to these examples in any way. It should be noted that the testing and evaluation methods in the examples are as follows. It should be noted that when "parts" are used, they refer to "parts by weight" unless otherwise specified; and when "%" are used, they refer to "% by weight" unless otherwise specified.

[0129] <Determination of high-speed adhesive strength (I) of glass plates (after placement at 23°C for 30 minutes)> In an environment of 23°C and 50% RH, the protective film on the surface after the release liner has been peeled off was cut into pieces 25mm wide and 140mm long, and then pressed onto the surface of a glass plate (ordinary soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2kg hand roller in one reciprocating motion to make a sample.

[0130] After placing the sample at an ambient temperature of 23°C for 30 minutes, the sample was placed in a tensile testing machine to begin the tensile test. The tensile test conditions were set at 23°C, 50% RH, a peel angle of 180 degrees, and a peel speed (tensile speed) of 1800 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 set as the high-speed adhesion force (I) to the glass plate (sometimes simply referred to as high-speed adhesion force (I)). The tensile testing machine used was the Shimadzu Corporation's "Autograph AG-Xplus HS 6000 mm / min high-speed mode (AG-50NX plus)".

[0131] <Determination of high-speed adhesive strength (II) of glass plates (after 1 day at 50°C)> In an environment of 23°C and 50% RH, the protective film on the surface after the release liner has been peeled off was cut into pieces 25mm wide and 140mm long, and pressed onto the surface of a glass plate (ordinary soda-lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2kg hand roller in one reciprocating motion to make a sample.

[0132] After placing the sample at an ambient temperature of 50°C for one day, the sample was placed in a tensile testing machine to begin the tensile test. The tensile test conditions were set at 23°C, 50% RH, a peel angle of 180 degrees, and a peel speed (tensile speed) of 1800 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 set as the high-speed adhesion force (II) to the glass plate (sometimes simply referred to as high-speed adhesion force (II)). The tensile testing machine used was the Shimadzu Corporation's "Autograph AG-Xplus HS 6000 mm / min high-speed mode (AG-50NX plus)".

[0133] <Calculation of the rate of increase in high-speed adhesive force of glass plates over time> It is calculated using the formula [High-speed adhesive force (II) / High-speed adhesive force (I)] × 100 (%).

[0134] <Cutting ability> Cut 1 cm into the center of the adhesive layer (25 mm wide x 140 mm long) on ​​the side where the protective film of the release liner has been peeled off, at a 90-degree angle. Mark the case where adhesive residue is visually confirmed as G (good), and the case where no adhesive residue is confirmed as B (better).

[0135] [Manufacturing Example 1]: Manufacturing of urethane prepolymer A 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 stirring rod, and stirring blades were equipped with 347g of polypropylene glycol (SANNIX PP-2000, manufactured by Sanyo Chemical Industry Co., Ltd.), 47g of polyester polyol (Kuraray Polyol P-2010, manufactured by Kuraray Corporation), 110g of toluene (TOSOH Corporation) as a solvent, and 0.041g of bismuth octoate (Nippon Kagaku S.A., Ltd.) as a catalyst. Nitrogen replacement was carried out at room temperature for 1 hour while stirring. Then, under nitrogen inflow, hexamethylene diisocyanate (product name "HDI", manufactured by TOSOH) 33.5g was added while stirring. The solution temperature in the experimental apparatus was controlled at 90±2℃ in a water bath and maintained for 4 hours. Then, polypropylene glycol (product name "GP1000", manufactured by Sanyo Chemical Industries) 44g was added. The solution temperature in the experimental apparatus was controlled at 90±2℃ in a water bath and maintained for 2 hours. Then, hexamethylene diisocyanate (product name "HDI", manufactured by TOSOH) 25.4g was added. The solution temperature in the experimental apparatus was controlled at 90±2℃ in a water bath and maintained for 2 hours, resulting in a solution of urethane prepolymer A. It should be noted that during polymerization, toluene was added dropwise to prevent a decrease in agitation caused by temperature control and viscosity increase during polymerization. The total amount of toluene added was 380g. The solid content concentration of the urethane prepolymer A solution was 50% by weight.

[0136] [Example 1] A urethane-based adhesive composition (1) was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.0 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.

[0137] 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.

[0138] The results are shown in Tables 1 and 2.

[0139] [Example 2] A urethane-based adhesive composition (2) was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.0 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-6001 (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.

[0140] The urethane-based adhesive composition (2) was used instead of the urethane-based adhesive composition (1), and otherwise the same procedure was followed as in Example 1 to obtain the adhesive layer (2) and the surface protective film (2). Various evaluations were performed after 5 days of aging at room temperature.

[0141] The results are shown in Tables 1 and 2.

[0142] [Example 3] A urethane-based adhesive composition (3) was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.0 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 X-22-4272 (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.

[0143] The urethane-based adhesive composition (3) was used instead of the urethane-based adhesive composition (1), and otherwise the same procedure was followed as in Example 1 to obtain the adhesive layer (3) and the surface protective film (3). Various evaluations were performed after 5 days of aging at room temperature.

[0144] The results are shown in Tables 1 and 2.

[0145] [Example 4] A urethane-based adhesive composition (4) was obtained by diluting 100 parts by weight of urethane prepolymer A, 3.0 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-615A (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.

[0146] The urethane-based adhesive composition (4) was used instead of the urethane-based adhesive composition (1), and otherwise the same procedure was followed as in Example 1 to obtain the adhesive layer (4) and the surface protective film (4). Various evaluations were performed after 5 days of aging at room temperature.

[0147] The results are shown in Tables 1 and 2.

[0148] [Example 5] A urethane-based adhesive composition (5) was obtained by diluting 100 parts by weight of urethane prepolymer A, 6.0 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-615A (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.

[0149] The urethane-based adhesive composition (5) was used instead of the urethane-based adhesive composition (1), and otherwise the same procedure was followed as in Example 1 to obtain the adhesive layer (5) and the surface protective film (5). Various evaluations were performed after 5 days of aging at room temperature.

[0150] The results are shown in Tables 1 and 2.

[0151] [Comparative Example 1] A urethane-based adhesive composition (C1) was obtained by diluting 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 Co., Ltd.) as a crosslinking agent, 0.10 parts by weight of KF-640 (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.

[0152] The urethane-based adhesive composition (C1) was used instead of the urethane-based adhesive composition (1), and otherwise the same procedure was followed as in Example 1 to obtain an adhesive layer (C1) and a surface protective film (C1). Various evaluations were performed after 5 days of aging at room temperature.

[0153] The results are shown in Tables 1 and 2. [Examples 6-10] For each surface protective film (1) to (5) obtained in Examples 1 to 5, the release liner was peeled off and the adhesive layer was pasted to the polarizing plate (manufactured by Nitto Denko Corporation, trade name "TEG1465DUHC") which is an optical component, and an optical component with a surface protective film was obtained.

[0154] [Examples 11-15] For each surface protective film (1) to (5) obtained in Examples 1 to 5, the release liner was peeled off and the adhesive layer was pasted to the conductive film (manufactured by Nitto Denko Corporation, trade name "ELECRYSTA V270L-TFMP") which is an electronic component, and an electronic component with a surface protective film was obtained.

[0155] Industrial availability The surface protective film of the present invention can be used for any suitable application. Preferably, the surface protective film of the present invention is preferred for use in the fields of optical components and electronic components.

Claims

1. A surface protective film comprising an adhesive layer made of a urethane-based adhesive, This carbamate-based adhesive contains carbamate polymers. This urethane-based adhesive is formed from a urethane-based adhesive composition. This urethane-based adhesive composition comprises a base polymer A and an organosilicon compound B. This urethane polymer is a prepolymer type urethane polymer. The base polymer A is a urethane prepolymer. The organosilicon compound B comprises at least one selected from the group consisting of organosilicon compounds having a polyether structure and organosilicon compounds having a methanol structure. The weight-average molecular weight (Mw) of this organosilicon compound B is over 2000.

2. The surface protective film according to claim 1, wherein, The urethane-based adhesive composition comprises a polyfunctional isocyanate compound, wherein the equivalent ratio of the NCO groups in the polyfunctional isocyanate compound to the OH groups in the urethane prepolymer, i.e., NCO / OH, is 1.50 or less.

3. The surface protective film according to claim 1, wherein, After the adhesive layer is adhered to the glass plate and placed at an ambient temperature of 23°C for 30 minutes, the average peel force when the surface protective film is peeled from the glass plate at a peel angle of 180 degrees and a peel speed of 1800 mm / min is defined as high-speed adhesion force I. After the adhesive layer is adhered to the glass plate and placed at an ambient temperature of 50°C for 1 day, the average peel force when the surface protective film is peeled from the glass plate at a peel angle of 180 degrees and a peel speed of 1800 mm / min is defined as high-speed adhesion force II. The rate of increase in high-speed adhesion to glass plates over time, defined as [High-speed adhesion II / High-speed adhesion I] × 100%, is less than 200%.

4. The surface protective film according to claim 1, wherein, The organosilicon compound B comprises an organosilicon compound having a polyether structure.

5. The surface protective film according to claim 4, wherein, The organosilicon compound having a polyether structure is at least one selected from the group consisting of reactive silicone oils and non-reactive silicone oils with an HLB value of less than 15.

6. The surface protective film according to claim 1, wherein, The weight-average molecular weight (Mw) of the organosilicon compound B is above 10,000.

7. An optical component comprising a surface protective film as claimed in any one of claims 1 to 6.

8. An electronic component comprising a surface protective film as claimed in any one of claims 1 to 6.

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