Surface protective film

Abstract

To provide a surface protective film that can effectively suppress generation of bubbles when subjected to high-temperature and high-pressure treatment after an adhesive layer is attached to an adherend and then returned to ordinary temperature and pressure, and further to provide an optical device and an electronic device comprising the surface protective film.SOLUTION: According to an embodiment of the present invention, a surface protective film is provided which comprises an adhesive layer, the adhesive layer comprising an acrylic adhesive, the acrylic adhesive being formed from an acrylic adhesive composition, the acrylic adhesive containing an oligomer component, at least 50 wt.% of the oligomer component being an oligomer A having a calculated Tg of 50°C or lower, the acrylic adhesive composition including an acrylic resin as a base polymer, and the Hansen solubility parameter distance Ra between the acrylic resin and the oligomer A being equal to or lower than 3 MPa0.5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a surface protection film, and to optical and electronic devices that include such a surface protection film. [Background technology]

[0002] BACKGROUND ART In the manufacturing process of optical devices and electronic devices, surface protection films having pressure-sensitive adhesive layers are used to prevent scratches on the surfaces of optical and electronic components and to impart impact resistance during processing, assembly, inspection, transportation, and the like.

[0003] In order to pressure-bond the pressure-sensitive adhesive layer to the adherend after it has been attached to the adherend, the surface protection film may be subjected to high-temperature, high-pressure treatment using an autoclave, etc. After such high-temperature, high-pressure treatment, it is necessary to return the film to room temperature and normal pressure.

[0004] However, conventional surface protection films have the problem that when the adhesive layer is attached to an adherend, subjected to high-temperature and high-pressure treatment, and then returned to room temperature and normal pressure, air bubbles (typically small air bubbles approximately several millimeters in diameter) are likely to form at the interface between the adhesive layer and the adherend at the cut end.

[0005] A technology has been reported for suppressing the formation of bubbles when a surface protection panel and an image display panel are bonded together with a full-surface adhesive sheet and then autoclaved (Patent Document 1). Patent Document 1 reports that by appropriately adjusting the storage modulus of the adhesive layer of the full-surface adhesive sheet and setting the loss tangent of the dynamic viscoelastic spectrum at a frequency of 1 Hz and 20°C to 0.6 to 1.5, it becomes difficult for bubbles to be mixed in, and even if bubbles are mixed in, they can be removed by autoclaving or the like, and the formation of bubbles can be suppressed even at high temperatures.

[0006] However, when the technology described in Patent Document 1 was reexamined, no clear correlation was found between the value of the loss tangent at a frequency of 1 Hz and the presence or absence of the bubble suppression effect, and the loss tangent at a frequency of 1 Hz is not an appropriate indicator of bubble suppression. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-231358 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a surface protection film that can sufficiently suppress the generation of bubbles even when subjected to high-temperature and high-pressure treatment after the pressure-sensitive adhesive layer is attached to an adherend and then returned to room temperature and normal pressure, and also to provide optical devices and electronic devices that include such a surface protection film. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by using, as the adhesive constituting the adhesive layer included in the surface protection film, an acrylic adhesive formed from an acrylic adhesive composition containing an acrylic resin as a base polymer and a specific oligomer, and have completed the present invention.

[0010] [1] A surface protection film according to an embodiment of the present invention is a surface protection film including a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer being composed of an acrylic pressure-sensitive adhesive, the acrylic pressure-sensitive adhesive being formed from an acrylic pressure-sensitive adhesive composition, the acrylic pressure-sensitive adhesive including an oligomer component, 50% by weight or more of the oligomer component being oligomer A having a calculated Tg of 50°C or less, the acrylic pressure-sensitive adhesive composition including an acrylic resin as a base polymer, and the Hansen solubility parameter distance Ra between the acrylic resin and the oligomer A being 3 MPa. 0.5 The following is the result. [2] In the surface protective film according to the above [1], the oligomer A may contain vinyl acetate as a monomer unit. [3] In the surface protection film according to the above [1] or [2], the content of the oligomer A in the acrylic pressure-sensitive adhesive may be 0.1 to 30 parts by weight per 100 parts by weight of the solid content. [4] In the surface protection film according to any one of the above [1] to [3], the pressure-sensitive adhesive layer may have a thickness of 0.5 μm to 100 μm. [5] An optical device according to an embodiment of the present invention includes the surface protection film according to any one of [1] to [4] above. [6] An electronic device according to an embodiment of the present invention includes the surface protection film according to any one of [1] to [4] above. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a surface protection film that can sufficiently suppress the generation of bubbles even when the pressure-sensitive adhesive layer is attached to an adherend, subjected to high-temperature and high-pressure treatment, and then returned to room temperature and normal pressure. It is also possible to provide optical devices and electronic devices that include such a surface protection film. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this specification, the term "(meth)acrylic" means "acrylic and / or methacrylic," the term "(meth)acrylate" means "acrylate and / or methacrylate," the term "(meth)allyl" means "allyl and / or methallyl," and the term "(meth)acrolein" means "acrolein and / or methacrolein." Furthermore, in this specification, the term "acid (salt)" means "acid and / or its salt." Examples of salts include alkali metal salts and alkaline earth metal salts, and specific examples include sodium salts and potassium salts.

[0014] ≪≪1. Surface protection film≫≫ The surface protection film according to the embodiment of the present invention includes a pressure-sensitive adhesive layer.

[0015] The surface protection film according to the embodiment of the present invention may include any appropriate other layer as long as it includes a pressure-sensitive adhesive layer. Such other layer may be a single layer or two or more layers. Examples of such other layers include a substrate layer, a release liner (also called a release sheet or separator), an antistatic layer, and an antifouling layer.

[0016] A surface protection film according to a representative embodiment of the present invention includes a pressure-sensitive adhesive layer and a substrate layer. The surface protection film according to one representative embodiment of the present invention has a laminated structure in which the pressure-sensitive adhesive layer and the substrate layer are laminated in this order, and the pressure-sensitive adhesive layer is the outermost layer.

[0017] A surface protection film according to another exemplary embodiment of the present invention has a laminated structure in which a release liner, a pressure-sensitive adhesive layer, and a substrate layer are laminated in this order, with the release liner being the outermost layer.

[0018] The thickness of the surface protection film according to the embodiment of the present invention is preferably 10 μm to 500 μm, more preferably 15 μm to 400 μm, even more preferably 20 μm to 350 μm, still more preferably 25 μm to 300 μm, particularly preferably 30 μm to 200 μm, and most preferably 35 μm to 100 μm.

[0019] Figure 1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention. In Figure 1, surface protection film 100 comprises a release liner 10, a pressure-sensitive adhesive layer 20, and a base layer 30. In the embodiment shown in Figure 1, release liner 10 and pressure-sensitive adhesive layer 20 are laminated directly to each other, and pressure-sensitive adhesive layer 20 and base layer 30 are laminated directly to each other. Release liner 10 can be peeled off when in use.

[0020] The surface protection film according to the embodiment of the present invention is cut to a size of 5 mm wide x 100 mm long, and the adhesive layer (if a release liner is provided, the adhesive layer is exposed by peeling off the release liner) is attached to the surface of the top coat layer side of the anti-glare film with an antifouling layer (produced in Production Example 1 described later) to a size of 5 mm wide x 10 mm long (contact area 50 mm 2 ) are laminated together so that the portions overlap, and the laminate is left to stand for 30 minutes in an environment of a temperature of 23°C and a humidity of 50% RH. Then, using a universal tensile tester (manufactured by Shimadzu Corporation, product name: "Autograph AG-Xplus HS 6000 mm / min high-speed model (AG-50NX plus)") in an environment of a temperature of 23°C and a humidity of 50% RH, a portion (width 5 mm x length 10 mm) of the surface protective film protruding from the edge of the anti-glare film with an anti-fouling layer is gripped and pulled from the surface of the anti-glare film with an anti-fouling layer in the shear direction at a peel angle of 0 degree at a pulling rate of 1 mm / min, and the shear adhesive strength is preferably 20 N / 50 mm. 2 or less, more preferably 15N / 50mm 2 or less, and more preferably 12N / 50mm 2 or less, and particularly preferably 10N / 50mm 2If the shear adhesive strength is within the above range, even if curling occurs when the film is attached to a film substrate such as a polarizing plate, it can be relaxed over time, making it possible to produce a flat laminate. The lower limit of the shear adhesive strength is preferably 0.5 N / 50 mm 2 More preferably, 1N / 50mm 2 More preferably, 3N / 50mm 2 That's all. If the lower limit of the shear adhesive strength is too low, problems such as lifting or peeling may easily occur when a stress is applied to the protective film in the lateral direction. The method for measuring the shear adhesive strength will be described in detail later.

[0021] The surface protection film according to the embodiment of the present invention can be produced by any suitable method, for example, a known method for producing a surface protection film including a substrate layer and a pressure-sensitive adhesive layer.

[0022] The pressure-sensitive adhesive layer included in the surface protection film according to an embodiment of the present invention may be formed by a formation method generally referred to as a "direct method" or a formation method generally referred to as a "transfer method." The direct method is a method in which a pressure-sensitive adhesive composition according to an embodiment of the present invention is applied to a substrate layer, and if necessary, heating, irradiation with active energy rays (such as ultraviolet rays), drying, etc. are performed to form a pressure-sensitive adhesive layer. The transfer method is a method in which a pressure-sensitive adhesive composition according to an embodiment of the present invention is applied to a release paper or the like, dried, to form a pressure-sensitive adhesive layer, and the formed pressure-sensitive adhesive layer is transferred to a substrate layer.

[0023] Examples of the application method include a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, air knife coater, spray coater, comma coater, direct coater, and roll brush coater.

[0024] <1-1. Adhesive layer> The surface protection film according to the embodiment of the present invention includes a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer may be a single layer or may be two or more layers. The pressure-sensitive adhesive layer is typically a single layer.

[0025] The thickness of the pressure-sensitive adhesive layer is preferably 0.5 μm to 100 μm, more preferably 1 μm to 70 μm, even more preferably 1.5 μm to 50 μm, still more preferably 2 μm to 40 μm, particularly preferably 2.5 μm to 30 μm, and most preferably 3 μm to 25 μm.

[0026] The pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive. The acrylic pressure-sensitive adhesive is formed from an acrylic pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer composed of an acrylic pressure-sensitive adhesive formed from the acrylic pressure-sensitive adhesive composition.

[0027] <1-1-a. Oligomer Components> In an embodiment of the present invention, the acrylic pressure-sensitive adhesive contains an oligomer component. The oligomer component may be of only one type, or of two or more types.

[0028] The content of the oligomer component in the acrylic pressure-sensitive adhesive may be any appropriate content ratio within a range that does not impair the effects of the present invention. In order to further exhibit the effects of the present invention, the content of the oligomer component in the acrylic pressure-sensitive adhesive is preferably 0.1 to 40 parts by weight, more preferably 1 to 30 parts by weight, even more preferably 3 to 25 parts by weight, particularly preferably 5 to 20 parts by weight, and most preferably 7 to 15 parts by weight, relative to 100 parts by weight of the solid content.

[0029] The weight average molecular weight of the oligomer component is preferably less than 20,000, more preferably 50 or more and less than 15,000, even more preferably 100 or more and less than 10,000, more preferably 1,000 to 9,500, even more preferably 2,000 to 9,000, and particularly preferably 3,000 to 8,500.

[0030] The oligomer component contains an oligomer A having a calculated Tg of 50°C or less. If the calculated Tg of the oligomer A is too high, the effects of the present invention may not be achieved. For example, when the pressure-sensitive adhesive layer is attached to an adherend, subjected to high-temperature and high-pressure treatment, and then returned to room temperature and normal pressure, bubbles may be generated. Furthermore, if the calculated Tg of the oligomer A is too high, the shear adhesive strength of the pressure-sensitive adhesive layer may become too high. As a result, for example, when the pressure-sensitive adhesive layer is attached to a film adherend using a laminator or the like, curling may occur due to tension, etc., and the curl may remain unrelieved over time, making it impossible to attach the layer in the next step. The lower limit of the calculated Tg of the oligomer A is, for example, 0°C or higher, in terms of plasticity at the temperature of use, etc.

[0031] The content of oligomer A in the oligomer component is 50% by weight or more, preferably 50% by weight to 100% by weight, more preferably 60% by weight to 100% by weight, even more preferably 70% by weight to 100% by weight, still more preferably 80% by weight to 100% by weight, particularly preferably 90% by weight to 100% by weight, and most preferably 95% by weight to 100% by weight.

[0032] Since the acrylic adhesive contains an oligomer component, of which 50% by weight or more is oligomer A, the surface protection film according to an embodiment of the present invention can sufficiently suppress the generation of bubbles even when the adhesive layer is attached to an adherend, subjected to high-temperature and high-pressure treatment, and then returned to room temperature and normal pressure.

[0033] The calculated Tg is a calculated glass transition temperature that can be calculated by the following Fox formula (1).

[0034] 1 / Calculation Tg=Σ(Wi / Tgi)=W1 / Tg1+W2 / Tg2+···+Wi / Tgi···(1)

[0035] In Fox's formula (1), W1, W2, ... Wi represent the weight fractions (wt%) of monomer component 1, monomer component 2, ... monomer component i that make up the oligomer relative to the total monomer components, and Tg1, Tg2, ... Tgi represent the glass transition temperatures (units: absolute temperature: K) of the homopolymers of monomer component 1, monomer component 2, ... monomer component i. The unit of the calculated Tg calculated in Fox's formula (1) is absolute temperature (K).

[0036] The glass transition temperature of a homopolymer used to calculate the calculated Tg can be a value listed in a publicly available document. Specifically, the value listed in "Polymer Handbook 3rd Edition" (A. WILEY-INTERSCIENCE PUBLICATION, 1989) can be used. For a monomer for which multiple values are listed in the "Polymer Handbook 3rd Edition," the highest value is used.

[0037] For monomers for which the glass transition temperature of the homopolymer is not disclosed in publicly available documents, values measured by general thermal analysis, such as differential thermal analysis or dynamic viscoelasticity measurement, can be used. For example, 100 parts by weight of the monomer, 0.2 parts by weight of 2,2'-azobisisobutyronitrile, and 200 parts by weight of ethyl acetate as the polymerization solvent are charged into a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser, and the mixture is stirred for 1 hour while passing nitrogen gas through. After removing oxygen from the polymerization system in this manner, the temperature is raised to 63°C and the reaction is continued for 10 hours. The mixture is then cooled to room temperature to obtain a homopolymer solution with a solids concentration of 33% by weight. This homopolymer solution is then cast onto a release liner and dried to prepare a test sample (sheet-like homopolymer) approximately 2 mm thick. This test sample was punched out into a disk with a diameter of 7.9 mm, sandwiched between parallel plates, and the viscoelasticity was measured in shear mode using a viscoelasticity tester (TA Instruments Japan, model name "ARES") while applying a shear strain of 1 Hz over a temperature range of -70°C to 150°C at a heating rate of 5°C / min. The temperature corresponding to the peak top temperature of tan δ can be taken as the Tg of the homopolymer.

[0038] The surface protection film according to an embodiment of the present invention is characterized in that the Hansen solubility parameter distance Ra between the acrylic resin (the acrylic resin as the base polymer contained in the acrylic pressure-sensitive adhesive composition) described below and the oligomer A is 3 MPa. 0.5 The Hansen solubility parameter distance Ra between acrylic resin and oligomer A is 3 MPa. 0.5 When the Hansen solubility parameter distance Ra between the acrylic resin and oligomer A is 3 MPa or less, the effects of the present invention can be fully exhibited, and typically, a surface protection film can be provided that can fully suppress the generation of bubbles even when the pressure-sensitive adhesive layer is attached to an adherend, subjected to high-temperature and high-pressure treatment, and then returned to room temperature and normal pressure. 0.5If the distance is too large, exceeding 0.15 MPa, the effects of the present invention may not be exhibited, and typically, when the pressure-sensitive adhesive layer is attached to an adherend, subjected to high-temperature and high-pressure treatment, and then returned to room temperature and normal pressure, bubbles may be generated. The lower limit of the Hansen solubility parameter distance Ra between the acrylic resin and oligomer A is, for example, 0.15 MPa, from the viewpoint of the expression of properties derived from oligomer A. 0.5 That's all.

[0039] The Hansen solubility parameter (HSP) is the solubility parameter introduced by Hildebrand divided into three components: the dispersion term δD, the polarization term δP, and the hydrogen bonding term δH. δD represents the energy derived from the dispersion force between molecules. δP represents the energy derived from the polar force between molecules. δH represents the energy derived from the hydrogen bonding force between molecules. The units of each component are usually MPa. 0.5 The three components, the dispersion term δD, the polarization term δP, and the hydrogen bonding term δH, define a point (vector) in a three-dimensional space known as Hansen space.

[0040] The Hansen solubility parameter distance (HSP distance) Ra between the acrylic resin and oligomer A is the distance in the Hansen space between the point (δDx, δPx, δHx) corresponding to the acrylic resin (x) and the point (δDy, δPy, δHy) corresponding to the oligomer A (y), and can be calculated by the following formula (2).

[0041] The Hansen solubility parameter distance between acrylic resin and oligomer A is Ra = {4 × (δDx - δDy) 2 +(δPx-δPy) 2 +(δHx-δHy) 2} 0.5 ···(2)

[0042] Details of the Hansen solubility parameters (HSP) are described, for example, in "Hansen Solubility Parameters; A Users Handbook" (CRC Press, 2007).

[0043] The δD, δP, and δH of the acrylic resin and oligomer A can be determined by calculation using known software such as HSPiP (version 5) based on the monomer units constituting each of the acrylic resin and oligomer A and the content of the monomer units. Specifically, the δD, δP, and δH of each monomer unit can be calculated individually, and the calculated δD, δP, and δH can be weighted by the content of the monomer unit to obtain weighted average values, which can be used as the δD, δP, and δH of the acrylic resin and oligomer A.

[0044] If temperature conditions are required in the calculation, the temperature is set to 23°C. The calculated values of δD, δP, and δH may vary slightly depending on the software used. However, the difference is usually negligible when calculating Ra.

[0045] Any appropriate oligomer A can be used as the oligomer A as long as it satisfies the above conditions and does not impair the effects of the present invention. In order to further demonstrate the effects of the present invention, the oligomer A preferably contains vinyl acetate as a monomer unit. When the oligomer A contains vinyl acetate as a monomer unit, the effects of the present invention can be further demonstrated, and typically, a surface protection film can be provided that can more sufficiently suppress the generation of bubbles, even when the pressure-sensitive adhesive layer is attached to an adherend, subjected to high-temperature and high-pressure treatment, and then returned to room temperature and normal pressure.

[0046] The content of vinyl acetate in all monomer units constituting oligomer A may be any appropriate content ratio as long as the effects of the present invention are not impaired. In order to further exhibit the effects of the present invention, the content of vinyl acetate in all monomer units constituting oligomer A is preferably 20% by weight or more, more preferably 50% by weight to 99.9% by weight, even more preferably 70% by weight to 99% by weight, particularly preferably 80% by weight to 99% by weight, and most preferably 90% by weight to 99% by weight.

[0047] The oligomer A may contain other monomers as monomer units other than vinyl acetate. The content of other monomers in all the monomer units constituting the oligomer A is preferably 80% by weight or less, more preferably 0.1% by weight to 50% by weight, even more preferably 1% by weight to 30% by weight, particularly preferably 1% by weight to 20% by weight, and most preferably 1% by weight to 10% by weight.

[0048] The other monomers may be one kind or two or more kinds. Examples of such other monomers include those that can be contained in the composition (A) that forms the acrylic resin described below by polymerization: (Component a) a (meth)acrylic acid alkyl ester in which the alkyl group in the alkyl ester moiety has 4 to 12 carbon atoms; (b) at least one selected from the group consisting of (meth)acrylic acid esters having an OH group and (meth)acrylic acid; (Component c) Vinyl ester monomers (excluding vinyl acetate) Among these, the component a is preferred as the other monomer.

[0049] The content of oligomer A in the acrylic pressure-sensitive adhesive may be any appropriate content ratio as long as the effects of the present invention are not impaired. In order to further exhibit the effects of the present invention, the content of oligomer A in the acrylic pressure-sensitive adhesive is preferably 0.1 to 30 parts by weight, more preferably 1 to 25 parts by weight, even more preferably 3 to 20 parts by weight, particularly preferably 5 to 15 parts by weight, and most preferably 7 to 10 parts by weight, relative to 100 parts by weight of the solid content.

[0050] <1-1-b. Acrylic Pressure-Sensitive Adhesive Composition> In an embodiment of the present invention, the acrylic pressure-sensitive adhesive is formed from an acrylic pressure-sensitive adhesive composition.

[0051] [Acrylic resin] The acrylic pressure-sensitive adhesive composition contains an acrylic resin as a base polymer, and the acrylic resin may be one type only or two or more types.

[0052] The content of the acrylic resin as a base polymer in the acrylic pressure-sensitive adhesive composition is typically, in terms of solid content, preferably 50 wt % to 99.9 wt %, more preferably 60 wt % to 99 wt %, even more preferably 70 wt % to 95 wt %, and particularly preferably 75 wt % to 90 wt %.

[0053] The weight average molecular weight of the acrylic resin is preferably 100,000 to 2,500,000, more preferably 200,000 to 2,000,000, even more preferably 250,000 to 1,500,000, and particularly preferably 300,000 to 1,000,000, in order to further exert the effects of the present invention.

[0054] As the acrylic resin, any appropriate acrylic resin can be adopted as long as it does not impair the effects of the present invention. As the acrylic resin, from the viewpoint of being able to further exhibit the effects of the present invention, the following is preferable: (Component a) a (meth)acrylic acid alkyl ester in which the alkyl group in the alkyl ester moiety has 4 to 12 carbon atoms; (b) at least one selected from the group consisting of (meth)acrylic acid esters having an OH group and (meth)acrylic acid; (Component c) Vinyl ester monomer Examples of the acrylic resin include an acrylic resin formed by polymerization from a composition (A) containing the following:

[0055] The component a, the component b, and the component c may each independently be one type or two or more types.

[0056] Examples of component a include n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Among these, n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred, and 2-ethylhexyl acrylate is more preferred, in terms of being able to further exhibit the effects of the present invention.

[0057] Examples of component b include (meth)acrylic acid and (meth)acrylic acid esters having an OH group, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. Among these, in terms of being able to further exhibit the effects of the present invention, preferred are hydroxyethyl (meth)acrylate and (meth)acrylic acid, more preferred are hydroxyethyl acrylate and acrylic acid, and even more preferred is acrylic acid.

[0058] Examples of component c include vinyl acetate, vinyl propionate, and vinyl laurate, with vinyl acetate being preferred in that it can further exert the effects of the present invention.

[0059] The composition (A) may contain a copolymerizable monomer (component d) other than components a, b, and c. The component d may be of only one type, or of two or more types.

[0060] Examples of the d component include (meth)acrylic acid alkyl esters in which the alkyl group in the alkyl ester moiety has 1 to 3 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate; carboxyl group-containing monomers (excluding (meth)acrylic acid) such as itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and acid anhydrides thereof (for example, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride); (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methyl ( ... Amide group-containing monomers such as methyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, and N-hydroxyethyl (meth)acrylamide; amino group-containing monomers such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl Heterocycle-containing vinyl monomers such as N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphate group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; isocyanates such as 2-methacryloyloxyethyl isocyanate. Examples of suitable monomers include anate group-containing monomers; (meth)acrylic acid esters having an alicyclic hydrocarbon group such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; (meth)acrylic acid esters having an aromatic hydrocarbon group such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and benzyl (meth)acrylate; olefins and dienes such as ethylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ether; and vinyl chloride.

[0061] A polyfunctional monomer may also be used as component (d). A polyfunctional monomer refers to a monomer having two or more ethylenically unsaturated groups in one molecule. Any appropriate ethylenically unsaturated group may be used as the ethylenically unsaturated group as long as the effects of the present invention are not impaired. Examples of such ethylenically unsaturated groups include radically polymerizable functional groups such as vinyl groups, propenyl groups, isopropenyl groups, vinyl ether groups (vinyloxy groups), and allyl ether groups (allyloxy groups). Examples of polyfunctional monomers include hexanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate.

[0062] As component d, (meth)acrylic acid alkoxyalkyl esters can also be used. Examples of (meth)acrylic acid alkoxyalkyl esters include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate.

[0063] As component d, in terms of being able to further exert the effects of the present invention, preferred examples include (meth)acrylic acid alkyl esters in which the alkyl group in the alkyl ester moiety has 1 to 3 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate; and heterocycle-containing vinyl monomers such as N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole.

[0064] The content of component a in the total amount of monomer components constituting the acrylic resin is preferably 25% by weight to 98% by weight, more preferably 35% by weight to 95% by weight, even more preferably 40% by weight to 80% by weight, particularly preferably 45% by weight to 70% by weight, and most preferably 50% by weight to 60% by weight, relative to the total amount of monomer components constituting the acrylic resin, in order to further exhibit the effects of the present invention.

[0065] The content of component b in the total amount of monomer components constituting the acrylic resin is preferably 1 to 40% by weight, more preferably 1 to 30% by weight, even more preferably 1.5 to 20% by weight, particularly preferably 2 to 15% by weight, and most preferably 2.5 to 10% by weight, relative to the total amount of monomer components constituting the acrylic resin, in order to further exhibit the effects of the present invention.

[0066] The content of component c in the total amount of monomer components constituting the acrylic resin is preferably 1 to 70% by weight, more preferably 10 to 65% by weight, even more preferably 20 to 60% by weight, particularly preferably 30 to 55% by weight, and most preferably 35 to 50% by weight, relative to the total amount of monomer components constituting the acrylic resin, in order to further exhibit the effects of the present invention.

[0067] The content of component d in the total amount of monomer components constituting the acrylic resin is preferably 0% by weight to 73% by weight, more preferably 0% by weight to 60% by weight, even more preferably 0% by weight to 50% by weight, particularly preferably 0% by weight to 40% by weight, and most preferably 0% by weight to 30% by weight, relative to the total amount of monomer components constituting the acrylic resin, in terms of being able to further exhibit the effects of the present invention.

[0068] Composition (A) may contain any appropriate other components as long as the effects of the present invention are not impaired. Examples of such other components include a polymerization initiator, a chain transfer agent, and a solvent. The content of these other components may be any appropriate content as long as the effects of the present invention are not impaired.

[0069] The polymerization initiator may be a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc., depending on the type of polymerization reaction. Only one type of polymerization initiator may be used, or two or more types may be used.

[0070] A thermal polymerization initiator is preferably used when obtaining an acrylic resin by solution polymerization. Examples of such thermal polymerization initiators include azo polymerization initiators (e.g., 2,2'-azobisisobutyronitrile (hereinafter sometimes referred to as AIBN), 2,2'-azobis-2-methylbutyronitrile (hereinafter sometimes referred to as AMBN), 2,2'-azobis(2-methylpropionate)dimethyl, 4,4'-azobis-4-cyanovaleric acid), peroxide polymerization initiators (e.g., benzoyl peroxide), and redox polymerization initiators. Known thermal polymerization initiators can be used as these thermal polymerization initiators.

[0071] The photopolymerization initiator can be preferably used when obtaining an acrylic resin by active energy ray polymerization. Examples of the photopolymerization initiator include a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, a photoactive oxime-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzyl-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, and a thioxanthone-based photopolymerization initiator. Known photopolymerization initiators can be used as these photopolymerization initiators.

[0072] The amount of the polymerization initiator used may be any appropriate amount as long as it does not impair the effects of the present invention. The amount of the polymerization initiator used is, for example, preferably 0.01 to 15 parts by weight, more preferably 0.05 to 10 parts by weight, even more preferably 0.08 to 5 parts by weight, and particularly preferably 0.1 to 3 parts by weight, relative to 100 parts by weight of the total amount of the monomer components constituting the acrylic resin.

[0073] As the chain transfer agent, known chain transfer agents can be used, and the chain transfer agent may be one kind or two or more kinds.

[0074] The amount of the chain transfer agent used may be any appropriate amount as long as it does not impair the effects of the present invention, and is, for example, preferably 0.01 to 15 parts by weight per 100 parts by weight of the total amount of the monomer components constituting the acrylic resin.

[0075] Any appropriate solvent can be used as the solvent as long as it does not impair the effects of the present invention. Examples of such solvents include organic solvents such as esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. Only one type of solvent may be used, or two or more types may be used.

[0076] The amount of the solvent used may be any appropriate amount within a range that does not impair the effects of the present invention.

[0077] The acrylic resin can be produced by any appropriate polymerization method as long as the effects of the present invention are not impaired. Examples of polymerization methods that can be used to polymerize the acrylic resin include solution polymerization, emulsion polymerization, bulk polymerization, and active energy ray polymerization by irradiation with ultraviolet rays or the like. Typical examples are solution polymerization and active energy ray polymerization, and solution polymerization is preferred.

[0078] As a method for supplying monomers when carrying out solution polymerization, a batch charging method in which the entire amount of the monomer components is supplied at once, a continuous supply (dropping) method, a divided supply (dropping) method, or the like can be appropriately adopted.

[0079] The temperature for solution polymerization can be appropriately selected depending on the types of monomers and solvents used, the type of polymerization initiator, etc., and is preferably 20° C. to 160° C., more preferably 30° C. to 140° C., even more preferably 40° C. to 120° C., and particularly preferably 50° C. to 100° C. The time for solution polymerization can be appropriately selected depending on the types of monomers and solvents used, the type of polymerization initiator, etc., and is preferably 1 hour to 24 hours, more preferably 1 hour to 12 hours.

[0080] In the solution polymerization, it is preferable to carry out the reaction at temperature T1 for X hours, and then further hold the reaction at temperature T2 (where T2>T1) for Y hours, in order to further exert the effects of the present invention.

[0081] T1 is preferably less than 90°C, more preferably less than 85°C, even more preferably less than 80°C, particularly preferably less than 75°C, and most preferably less than 70°C.

[0082] T2 only needs to satisfy T2>T1, preferably T2-T1>1°C, more preferably T2-T1>5°C, even more preferably T2-T1>10°C, even more preferably T2-T1>15°C, particularly preferably T2-T1>20°C, and most preferably T2-T1>25°C.

[0083] X is preferably 0.1 to 48, more preferably 1 to 24, further preferably 1 to 12, and particularly preferably 1 to 10.

[0084] Y is preferably 0.1 to 48, more preferably 1 to 24, even more preferably 2 to 24, still more preferably 3 to 24, particularly preferably 4 to 24, and most preferably 5 to 24.

[0085] [Crosslinking agent] The acrylic pressure-sensitive adhesive composition may contain a crosslinking agent. Use of the crosslinking agent can further enhance the effects of the present invention. The crosslinking agent may be one type only, or two or more types.

[0086] Examples of crosslinking agents include polyfunctional isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, as well as urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Among these, at least one selected from the group consisting of polyfunctional isocyanate-based crosslinking agents and epoxy-based crosslinking agents is preferred in terms of further exhibiting the effects of the present invention.

[0087] As the polyfunctional isocyanate-based crosslinking agent, a compound having two or more isocyanate groups (including isocyanate-regenerating polar groups in which the isocyanate group is temporarily protected by a blocking agent or oligomerization, etc.) in one molecule can be used. Specific examples of the polyfunctional isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (for example, manufactured by Tosoh Corporation, trade name: Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (for example, manufactured by Tosoh Corporation, trade name: Coronate HL), and isocyanurate of hexamethylene diisocyanate (for example, manufactured by Tosoh Corporation, trade name: Coronate HL). Examples of suitable polyisocyanates include isocyanate adducts such as those manufactured by Saw Chemicals under the trade name of Coronate HX; trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals under the trade name of Takenate D110N), trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals under the trade name of Takenate D120N), trimethylolpropane adducts of isophorone diisocyanate (for example, Mitsui Chemicals under the trade name of Takenate D140N), and trimethylolpropane adducts of hexamethylene diisocyanate (for example, Mitsui Chemicals under the trade name of Takenate D160N); polyether polyisocyanates, polyester polyisocyanates, and adducts of these with various polyols; and polyisocyanates multifunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc.

[0088] Examples of epoxy crosslinking agents (polyfunctional epoxy compounds) include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, and methyl ... Examples of epoxy crosslinking agents include diglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, and bisphenol-S-diglycidyl ether, as well as epoxy resins having two or more epoxy groups in the molecule. Examples of epoxy crosslinking agents include commercially available products such as "Tetrad C" (manufactured by Mitsubishi Gas Chemical Company, Inc.).

[0089] The content of the crosslinking agent in the acrylic pressure-sensitive adhesive composition may be any appropriate content within the range that does not impair the effects of the present invention. In order to further exhibit the effects of the present invention, the content is preferably 0.001 to 30 parts by weight, more preferably 0.01 to 20 parts by weight, even more preferably 0.1 to 15 parts by weight, particularly preferably 1 to 15 parts by weight, and most preferably 1.5 to 15 parts by weight, relative to 100 parts by weight of the acrylic resin as the base polymer.

[0090] 〔solvent〕 The acrylic pressure-sensitive adhesive composition may contain a solvent. Any appropriate solvent may be used as the solvent as long as it does not impair the effects of the present invention. Examples of such solvents include organic solvents such as esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. The solvent may be one type only, or two or more types may be used.

[0091] The content of the solvent may be any appropriate amount within the range that does not impair the effects of the present invention. The amount of such a solvent is, for example, 0 to 10,000 parts by weight, preferably 100 to 5,000 parts by weight, relative to 100 parts by weight of the acrylic resin as the base polymer.

[0092] [Other ingredients] The acrylic pressure-sensitive adhesive composition may contain any other appropriate components as long as they do not impair the effects of the present invention. Examples of such other components include other polymer components, oligomer components, crosslinking accelerators, crosslinking retarders, catalysts, crosslinking catalysts, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), fatty acid esters, silicone additives, antioxidants, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foil-like materials, UV absorbers, antioxidants, light stabilizers, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, and lubricants.

[0093] The content of other components in the acrylic pressure-sensitive adhesive composition is preferably 0 to 30 parts by weight, more preferably 0 to 20 parts by weight, and even more preferably 0 to 10 parts by weight, relative to 100 parts by weight of the acrylic resin as the base polymer.

[0094] In an embodiment of the present invention, the acrylic pressure-sensitive adhesive composition may contain the aforementioned oligomer component as another component. That is, the acrylic pressure-sensitive adhesive composition may contain an acrylic resin as a base polymer and an oligomer component. When the acrylic pressure-sensitive adhesive composition contains the oligomer component, an acrylic pressure-sensitive adhesive formed from the acrylic pressure-sensitive adhesive composition may contain the oligomer component.

[0095] The content of the oligomer component in the acrylic pressure-sensitive adhesive composition may be any appropriate content ratio as long as the effects of the present invention are not impaired. In order to further exhibit the effects of the present invention, the content of the oligomer component in the acrylic pressure-sensitive adhesive composition is preferably 0.1 to 40 parts by weight, more preferably 1 to 30 parts by weight, even more preferably 3 to 25 parts by weight, particularly preferably 5 to 20 parts by weight, and most preferably 7 to 15 parts by weight, relative to 100 parts by weight of the solid content.

[0096] As described above, the oligomer component contains oligomer A having a calculated Tg of 50°C or less, and the content of oligomer A in the oligomer component is 50% by weight or more, preferably 50% to 100% by weight, more preferably 60% to 100% by weight, even more preferably 70% to 100% by weight, still more preferably 80% to 100% by weight, particularly preferably 90% to 100% by weight, and most preferably 95% to 100% by weight. Therefore, the acrylic pressure-sensitive adhesive composition preferably contains oligomer A.

[0097] The content of oligomer A in the acrylic pressure-sensitive adhesive composition is preferably 0.1 to 30 parts by weight, more preferably 1 to 25 parts by weight, even more preferably 3 to 20 parts by weight, particularly preferably 5 to 15 parts by weight, and most preferably 7 to 10 parts by weight, relative to 100 parts by weight of the solid content, in order to further exhibit the effects of the present invention.

[0098] ≪1-2. Base material layer≫ The surface protection film according to the embodiment of the present invention preferably includes a substrate layer.

[0099] The substrate layer may be one layer or two or more layers. The substrate layer is typically one layer. The substrate layer may be stretched.

[0100] The thickness of the substrate layer is preferably 4 μm to 450 μm, more preferably 8 μm to 400 μm, still more preferably 12 μm to 350 μm, and particularly preferably 16 μm to 250 μm.

[0101] For the surface of the base layer on which the pressure-sensitive adhesive layer is not applied, a release treatment can be performed by adding a fatty acid amide, polyethyleneimine, a long-chain alkyl additive, or the like to the base layer, or a coating layer made of any appropriate release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent can be provided, for example, in order to form a roll that is easy to unwind.

[0102] Any appropriate material can be used as the material for the substrate layer depending on the application. Examples include plastic, paper, metal film, nonwoven fabric, etc. Plastic is preferred. That is, the substrate layer is preferably a plastic film. The substrate layer may be made of one material or two or more materials. For example, it may be made of two or more plastics.

[0103] Examples of the plastics include polyester resins, polyamide resins, and polyolefin resins. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include homopolymers of olefin monomers and copolymers of olefin monomers. Specific examples of polyolefin resins include homopolypropylene; propylene copolymers such as block copolymers, random copolymers, and graft copolymers containing ethylene as a copolymerization component; reactor TPO; ethylene polymers such as low-density, high-density, linear low-density, and ultra-low-density copolymers; and ethylene copolymers such as ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-methacrylic acid copolymers, and ethylene-methyl methacrylate copolymers.

[0104] The substrate layer may contain any appropriate additives as needed. Examples of additives that may be contained in the substrate layer include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, and pigments. The type, number, and amount of additives that may be contained in the substrate layer may be appropriately set depending on the purpose.

[0105] Examples of release liners include release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is silicone-treated, and release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin.

[0106] Examples of plastic films that can be used as liner substrates include polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, and ethylene-vinyl acetate copolymer films.

[0107] 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.

[0108] ≪≪2. Optical and Electronic Devices≫≫ The surface protection film according to an embodiment of the present invention is typically attached to exposed surfaces of optical or electronic components to prevent scratches on the surfaces of the optical or electronic components during processing, assembly, inspection, transportation, etc. in the manufacturing process of optical or electronic devices, and can be suitably used for surface protection of optical or electronic components. The optical device according to an embodiment of the present invention includes a surface protection film according to an embodiment of the present invention. The electronic device according to an embodiment of the present invention includes a surface protection film according to an embodiment of the present invention. [Example]

[0109] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows. The term "parts" means "parts by weight" unless otherwise specified, and the term "%" means "% by weight" unless otherwise specified.

[0110] <Evaluation of the number of bubbles generated after high-temperature, high-pressure treatment> The surface protection film was cut to a size of 70 mm wide x 70 mm long, the release liner was peeled off, and then the film was pressed with a hand roller onto the surface of the top coat layer side of an anti-glare film with an antifouling layer (produced in Production Example 1 described below) as an adherend, followed by lamination under pressure conditions of 0.25 MPa and 0.3 m / min, and the four sides from the surface protection film side were cut with a cutter to a width of 50 mm x length of 50 mm to obtain an evaluation sample. The film was then autoclaved for 15 minutes at 50°C and 5 atm, and then returned to room temperature and normal pressure. Immediately afterwards, the number of bubbles generated at the film edge was counted, and the number of bubbles generated was evaluated according to the following evaluation criteria (score): 5: No bubbles were observed (except for foreign matter bubbles). 4: Bubbles were observed on one or two of the edges. 3: Bubbles were observed on three of the edges. 2: Bubbles were observed on all edges. 1: Bubbles were observed all over the surface.

[0111] <Shear adhesive strength> The surface protection film was cut to a size of 5 mm wide x 100 mm long, and the adhesive layer (if a release liner was provided, the adhesive layer was exposed by peeling off the release liner) was attached to the surface of the top coat layer side of the anti-glare film with an antifouling layer (produced in Production Example 1 described below) in a size of 5 mm wide x 10 mm long (contact area 50 mm 2 The films were laminated under pressure at 0.25 MPa and 0.3 m / min, and left for 30 minutes in an environment at 23°C and 50% RH. Then, using a universal tensile tester (Shimadzu Corporation, product name: "Autograph AG-Xplus HS 6000 mm / min high-speed model (AG-50NX plus)"), the portion of the surface protective film that protruded from the edge of the anti-glare film with an anti-fouling layer was gripped and pulled from the surface of the anti-glare film with an anti-fouling layer in the shear direction at a peel angle of 0° at a pulling rate of 1 mm / min, and the maximum adhesive strength was recorded as the shear adhesive strength. It is not necessary to grip the entire protruding portion (5 mm wide x 10 mm long), as long as it was gripped sufficiently to allow pulling.

[0112] [Production Example 1]: Anti-glare film with anti-fouling layer (Preparation of Hard Coat Composition) As binder resins, 50 parts by weight of pentaerythritol polyacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300") and 50 parts by weight of urethane acrylate prepolymer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Shikou UV-1700TL") were used, 7.2 parts by weight of copolymer crosslinked particles of styrene and methyl methacrylate (MMA) (manufactured by Sekisui Plastics Co., Ltd., trade name "Techpolymer SSX-540TNR", average particle size 3.6 μm), 1.5 parts by weight of organic smectite (manufactured by Kunimine Industries Co., Ltd., trade name "Sumecton SAN") was used as a thixotropic agent, and 1.5 parts by weight of photopolymerization initiator (IGM A hard coat composition with a solids concentration of 50 wt% was prepared by mixing 3 parts by weight of a resin (manufactured by Kyoeisha Chemical Co., Ltd., product name "OMNIRAD907") and 0.15 parts by weight of a leveling agent (manufactured by Kyoeisha Chemical Co., Ltd., product name "POLYFLOW LE303") and diluting with a toluene / cyclopentanone mixed solvent (weight ratio 70 / 30). The above blending amounts are the amount of solids (non-volatile content), and the organically modified smectite was diluted with toluene to a solids content of 6 wt%. (Hard coat film manufacturing) The hard coat composition obtained above was applied to an 80 μm-thick triacetyl cellulose (TAC) film (manufactured by Konica Minolta Opto, Inc., product name "KC8UA") using a Comma Coater (registered trademark), and heated at 80°C for 1 minute. Thereafter, the hard coat composition was applied to a high-pressure mercury lamp with an integrated light dose of 300 mJ / cm. 2 The coating layer was cured by irradiation with ultraviolet light of 1000 kJ / cm, thereby obtaining a hard-coated film having an antiglare hard-coating layer with a thickness of 6.0 μm on the TAC film. (Manufacturing of optical adjustment layer) The hard-coated film obtained above was introduced into a roll-to-toll sputtering system, and while the film was running, the hard-coat layer was bombarded (plasma treatment with Ar gas), after which a 100 nm thick SiO2 layer was sputtered. A Si target was used to deposit the SiO2 layer, and the amount of oxygen introduced was adjusted using plasma emission monitoring (PEM) control to maintain the deposition mode in the transition region. (Formation of antifouling layer) A fluorine-based resin solution containing a perfluoroether with -(O-CF(CF3)-CF2)- in the main chain skeleton was applied to the surface SiO2 layer of the optical adjustment layer so that the thickness after drying would be 10 nm, forming an antifouling layer as a top coat layer.

[0113] [Production Example 2]: Production of acrylic copolymer (1) A four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser was charged with 100 parts by weight of 2-ethylhexyl acrylate (2EHA) (manufactured by Nippon Shokubai Co., Ltd.), 80 parts by weight of vinyl acetate (VAc) (manufactured by Showa Denko K.K.), 5 parts by weight of acrylic acid (AA) (manufactured by Nippon Shokubai Co., Ltd.), 0.3 parts by weight of Niper BW (manufactured by NOF Corp.), and 2,400 parts by weight of toluene. Nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 65 ° C. for 6 hours to carry out a polymerization reaction. The liquid temperature in the flask was then raised to 95 ° C. and maintained for 8 hours, after which it was cooled to obtain a solution of acrylic copolymer (1) with a weight average molecular weight of 470,000 (solid content: 38 wt%).

[0114] [Production Example 3]: Production of acrylic copolymer (2) A four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser was charged with 100 parts by weight of 2-ethylhexyl acrylate (2EHA) (manufactured by Nippon Shokubai Co., Ltd.), 80 parts by weight of vinyl acetate (VAc) (manufactured by Showa Denko K.K.), 5 parts by weight of acrylic acid (AA) (manufactured by Nippon Shokubai Co., Ltd.), 0.3 parts by weight of Niper BW (manufactured by NOF Corp.), and 2,400 parts by weight of toluene. Nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 65 ° C. for 6 hours to carry out a polymerization reaction. The liquid temperature in the flask was then raised to 95 ° C. and maintained for 2 hours, then cooled to obtain a solution of acrylic copolymer (2) with a weight average molecular weight of 470,000 (solid content: 38 wt%).

[0115] [Production Example 4]: Production of acrylic copolymer (3) A four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser was charged with 100 parts by weight of 2-ethylhexyl acrylate (2EHA) (manufactured by Nippon Shokubai Co., Ltd.), 80 parts by weight of vinyl acetate (VAc) (manufactured by Showa Denko K.K.), 5 parts by weight of acrylic acid (AA) (manufactured by Nippon Shokubai Co., Ltd.), 0.3 parts by weight of Niper BW (manufactured by NOF Corporation), and 2,400 parts by weight of toluene. Nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 65 ° C. for 6 hours to carry out a polymerization reaction. After cooling, a solution of acrylic copolymer (3) with a weight-average molecular weight of 470,000 (solid content: 38 wt%) was obtained.

[0116] [Production Example 5]: Production of methacrylic oligomer (1) A four-neck flask equipped with a stirring blade, thermometer, nitrogen gas inlet, and condenser was charged with 120 parts by weight of toluene, 95 parts by weight of cyclohexyl methacrylate (CHMA) (Mitsubishi Gas Chemical Co., Inc.), 5 parts by weight of acrylic acid (AA) (Nippon Shokubai Co., Ltd.), and 10 parts by weight of Nofumer MSD (NOF Corp.) as a chain transfer agent. After stirring at 60°C under a nitrogen atmosphere for 1 hour, 10 parts by weight of 2,2'-azobisisobutyronitrile (Wako Pure Chemical Industries, Ltd.) as a polymerization initiator was added, and the reaction was continued at 85°C for 3.5 hours to obtain a solution (solids content: 50% by weight) of methacrylic oligomer (1) with a weight-average molecular weight of 3,500 and a Tg of 67.8°C (calculated using the Fox equation).

[0117] [Production Example 6]: Production of methacrylic oligomer (2) A four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser was charged with 100 parts by weight of toluene, 40 parts by weight of 4-hydroxybutyl acrylate (4-HBA) (manufactured by Mitsubishi Chemical Corporation), 5 parts by weight of N-vinylpyrrolidone (NVP) (manufactured by Nippon Shokubai Co., Ltd.), 15 parts by weight of methyl methacrylic acid (MMA) (manufactured by Mitsubishi Gas Chemical Co., Inc.), 35 parts by weight of dicyclopentadienyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Co., Ltd.), and 3.5 parts by weight of methyl thioglycolate as a chain transfer agent. After stirring at 70°C under a nitrogen atmosphere for 1 hour, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator, and the mixture was reacted at 70°C for 2 hours, then at 80°C for 4 hours, and then at 90°C for 1 hour, yielding a solution of methacrylic oligomer (2) (solid content: 60% by weight) with a weight-average molecular weight of 4500 and a Tg of 44.6°C (calculated from Fox's equation).

[0118] [Example 1]: Production of surface protective film (1) To the solution of acrylic copolymer (1) obtained in Production Example 2, 10 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added as a crosslinking agent per 100 parts by weight of the solid content, and the mixture was diluted with methyl ethyl ketone so that the total solid content was 20% by weight, and stirred with a disperser to obtain adhesive composition (1). The obtained pressure-sensitive adhesive composition (1) was applied to a polyester resin substrate "Lumirror S10" (thickness 38 μm, manufactured by Toray Industries, Inc.) using a fountain roll so that the thickness after drying would be 15 μm, and the coating was dried at a drying temperature of 130°C for 30 seconds to form a pressure-sensitive adhesive layer (1) on the substrate. Next, the silicone-treated side of a release liner made of polyester resin and having a thickness of 19 μm, one side of which had been silicone-treated, was attached to the surface of the pressure-sensitive adhesive layer (1), and the resulting mixture was cured at 50°C for 48 hours to obtain a surface protection film (1) having a configuration of release liner / pressure-sensitive adhesive layer (1) / substrate layer. The resulting pressure-sensitive adhesive layer (1) was wrapped in a porous polytetrafluoroethylene (PTFE) membrane with an average pore size of 0.2 μm in a purse shape, and the opening was tied with string. The porous polytetrafluoroethylene membrane used was "Nitoflon (registered trademark) NTF1122" (average pore size 0.2 μm, porosity 75%, thickness 85 μm) available from Nitto Denko Corporation, or an equivalent. The wrapper was immersed in a sufficient amount of ethyl acetate and kept at room temperature (23°C) for 7 days. Analysis was performed by eluting only the sol component of the pressure-sensitive adhesive out of the membrane, revealing that the pressure-sensitive adhesive layer (1) contained 8 parts by weight of sol component per 100 parts by weight of solid component. This sol component was measured by gel permeation chromatography (GPC), and the weight-average molecular weight of the sol component and the proportion (weight percentage) of low-molecular-weight components with a molecular weight of 10,000 or less were calculated from the obtained molecular weight / weight distribution curve. Regarding the monomer composition ratio, 1 Analysis by H-NMR revealed that it was an oligomer (A) with a weight-average molecular weight of 6000 and a composition of vinyl acetate (VAc) / 2-ethylhexyl acrylate (2EHA) = 96 / 4 (weight ratio). The calculated Tg of this oligomer (A) was 25.9°C (calculated using the Fox equation). In addition, the Hansen solubility parameter distance Ra between the acrylic copolymer (1) and the oligomer (A) is 2.4 MPa. 0.5 It was calculated that: The results are shown in Table 1.

[0119] [Example 2]: Production of surface protective film (2) The same procedure as in Example 1 was carried out, except that the acrylic copolymer (2) obtained in Production Example 3 was used instead of the acrylic copolymer (1) obtained in Production Example 2, to obtain a pressure-sensitive adhesive composition (2) and a surface protection film (2) having a configuration of release liner / pressure-sensitive adhesive layer (2) / substrate layer. The resulting pressure-sensitive adhesive layer (2) was wrapped in a porous polytetrafluoroethylene (PTFE) membrane with an average pore size of 0.2 μm in a purse shape, and the opening was tied with string. The porous polytetrafluoroethylene membrane used was available from Nitto Denko Corporation under the trade name "Nitoflon (registered trademark) NTF1122" (average pore size 0.2 μm, porosity 75%, thickness 85 μm) or an equivalent. The wrapper was immersed in a sufficient amount of ethyl acetate and kept at room temperature (23°C) for 7 days. Analysis was performed by eluting only the sol component of the pressure-sensitive adhesive out of the membrane. It was found that the pressure-sensitive adhesive layer (2) contained 6 parts by weight of sol component per 100 parts by weight of solid component. This sol component was measured by gel permeation chromatography (GPC), and the weight-average molecular weight of the sol component and the proportion (weight percentage) of low-molecular-weight components with a molecular weight of 10,000 or less were calculated from the obtained molecular weight / weight distribution curve. Regarding the monomer composition ratio, 1 Analysis by H-NMR revealed that it was an oligomer (A) with a weight-average molecular weight of 6000 and a composition of vinyl acetate (VAc) / 2-ethylhexyl acrylate (2EHA) = 96 / 4 (weight ratio). The calculated Tg of this oligomer (A) was 25.9°C (calculated using the Fox equation). In addition, the Hansen solubility parameter distance Ra between the acrylic copolymer (2) and the oligomer (A) is 2.4 MPa. 0.5 It was calculated that: The results are shown in Table 1.

[0120] [Comparative Example 1]: Production of Surface Protection Film (C1) To the solution of acrylic copolymer (3) obtained in Production Example 4, 10 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent was added per 100 parts by weight of the solids content, and the mixture was diluted with methyl ethyl ketone to a total solids content of 20% by weight, followed by stirring with a disper to obtain a pressure-sensitive adhesive composition. To the obtained pressure-sensitive adhesive composition, 10 parts by weight of methacrylic oligomer (1) obtained in Production Example 5 was added per 100 parts by weight of the solids content, followed by stirring with a disper to obtain pressure-sensitive adhesive composition (C1). The obtained pressure-sensitive adhesive composition (C1) was applied to a polyester resin substrate "Lumilar S10" (thickness 38 μm, manufactured by Toray Industries, Inc.) using a fountain roll so that the thickness after drying would be 15 μm, and the coating was dried at 130°C for 30 seconds to form a pressure-sensitive adhesive layer (C1) on the substrate. Next, the silicone-treated side of a 19 μm thick polyester resin release liner, one side of which had been silicone-treated, was laminated to the surface of the pressure-sensitive adhesive layer (C1), and cured at 50°C for 48 hours to obtain a surface protection film (C1) consisting of release liner / pressure-sensitive adhesive layer (C1) / substrate layer. The resulting adhesive layer (C1) was wrapped in a porous polytetrafluoroethylene (PTFE) membrane with an average pore size of 0.2 μm in a purse shape, and the opening was tied with string. The porous polytetrafluoroethylene membrane used was "Nitoflon (registered trademark) NTF1122" (average pore size 0.2 μm, porosity 75%, thickness 85 μm) available from Nitto Denko Corporation, or an equivalent. The wrapper was immersed in a sufficient amount of ethyl acetate and kept at room temperature (23°C) for 7 days. Analysis was performed by eluting only the sol component of the adhesive out of the membrane, revealing that the adhesive layer (C1) contained 15 parts by weight of sol component per 100 parts by weight of solid component. This sol component was measured by gel permeation chromatography (GPC), and the weight-average molecular weight of the sol component and the proportion (weight percentage) of low-molecular-weight components with a molecular weight of 10,000 or less were calculated from the obtained molecular weight / weight distribution curve. Regarding the monomer composition ratio, 1 Analysis by H-NMR revealed that the mixture was a mixture of 5 parts by weight of oligomer (A) with a weight-average molecular weight of 6000 and a vinyl acetate (VAc) / 2-ethylhexyl acrylate (2EHA) composition of 96 / 4 (weight ratio), and 10 parts by weight of the previously added methacrylic oligomer (1). In other words, the content of oligomer (A) in the total oligomer components was 33% by weight. The calculated Tg of the oligomer (A) was 25.9°C (calculated from the Fox equation), and the calculated Tg of the methacrylic oligomer (1) was 67.8°C (calculated from the Fox equation). In addition, the Hansen solubility parameter distance Ra between the acrylic copolymer (1) and the oligomer (A) is 2.4 MPa.0.5 It was calculated that: The results are shown in Table 1.

[0121] [Comparative Example 2]: Production of Surface Protection Film (C2) The same procedure as in Comparative Example 1 was carried out except that methacrylic oligomer (2) was used instead of methacrylic oligomer (1), and a surface protection film (C2) having a structure of release liner / adhesive layer (C2) / substrate layer was obtained. The resulting adhesive layer (C2) was wrapped in a porous polytetrafluoroethylene (PTFE) membrane with an average pore size of 0.2 μm in a purse shape, and the opening was tied with string. The porous polytetrafluoroethylene membrane used was available from Nitto Denko Corporation under the trade name "Nitoflon (registered trademark) NTF1122" (average pore size 0.2 μm, porosity 75%, thickness 85 μm) or an equivalent. The wrapper was immersed in a sufficient amount of ethyl acetate and kept at room temperature (23°C) for 7 days. Analysis was performed by eluting only the sol component of the adhesive out of the membrane, revealing that the adhesive layer (C2) contained 15 parts by weight of sol component per 100 parts by weight of solid component. This sol component was measured by gel permeation chromatography (GPC), and the weight-average molecular weight of the sol component and the proportion (weight percentage) of low-molecular-weight components with a molecular weight of 10,000 or less were calculated from the resulting molecular weight distribution curve. Regarding the monomer composition ratio, 1 Analysis by H-NMR revealed that the mixture was a mixture of 5 parts by weight of oligomer (A) with a weight-average molecular weight of 6000 and a vinyl acetate (VAc) / 2-ethylhexyl acrylate (2EHA) composition of 96 / 4 (weight ratio), and 10 parts by weight of the previously added methacrylic oligomer (2). In other words, the content of oligomer (A) in the total oligomer components was 33% by weight. The calculated Tg of the oligomer (A) was 25.9°C (calculated from the Fox equation), and the calculated Tg of the methacrylic oligomer (2) was 44.6°C (calculated from the Fox equation). In addition, the Hansen solubility parameter distance Ra between the acrylic copolymer (1) and the oligomer (A) is 2.4 MPa. 0.5 It was calculated that: The results are shown in Table 1.

[0122] [Table 1]

[0123] [Example 3] The release liner was peeled off from each of the surface protection films (1) and (2) obtained in Examples 1 and 2, and the pressure-sensitive adhesive layer side was attached to a polarizing plate (manufactured by Nitto Denko Corporation, product name "TEG1465DUHC"), which is an optical component, to obtain an optical device.

[0124] [Example 4] The release liner was peeled off from each of the surface protection films (1) and (2) obtained in Examples 1 and 2, and the adhesive layer side was attached to a conductive film (manufactured by Nitto Denko Corporation, product name "ELECRYSTA V270L-TFMP"), which is an electronic component, to obtain an electronic device. [Industrial Applicability]

[0125] The surface protection film of the present invention can be used for any suitable purpose, such as preventing scratches on the surfaces of optical or electronic components during processing, assembly, inspection, transportation, etc. in the manufacturing process of optical or electronic devices. [Explanation of symbols]

[0126] 10 Release liner 20 adhesive layer 30 Base material layer 100 adhesive films

Claims

1. A surface protection film including a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive, and the acrylic pressure-sensitive adhesive is formed from an acrylic pressure-sensitive adhesive composition; The acrylic pressure-sensitive adhesive contains an oligomer component, 50% by weight or more of the oligomer component is oligomer A having a calculated Tg of 50°C or less, The acrylic pressure-sensitive adhesive composition contains an acrylic resin as a base polymer, The Hansen solubility parameter distance Ra between the acrylic resin and the oligomer A is 3 MPa. 0.5 Below is the Surface protection film.

2. The surface protection film according to claim 1 , wherein the oligomer A contains vinyl acetate as a monomer unit.

3. 2. The surface protection film according to claim 1, wherein the content of said oligomer A in said acrylic pressure-sensitive adhesive is 0.1 to 30 parts by weight per 100 parts by weight of solid content.

4. The surface protection film according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 0.5 μm to 100 μm.

5. An optical device comprising the surface protection film according to any one of claims 1 to 4.

6. An electronic device comprising the surface protection film according to any one of claims 1 to 4.

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