TW202026673A - Optical film with protective film - Google Patents

Abstract

The optical film (100) with a protective film of the present invention includes: an optical film (10) having an antifouling layer (4) on the outermost surface; and a surface protective film (70) temporarily attached to the antifouling layer of the optical film . The water contact angle of the antifouling layer is more than 100°. The protective film is provided with an adhesive layer (8) on the film substrate (7). The adhesion between the antifouling layer of the optical film and the adhesive layer of the surface protection film is less than 0.07 N/50 mm. The thickness of the adhesive layer is preferably 16 μm or more.

Description

Optical film with protective film

The present invention relates to an optical film temporarily attached with a surface protective film.

The anti-reflective film placed on the top surface of the image display device, the position detection film of the touch panel, the window film pasted on the window glass or display window, etc. are used in a state that can be contacted from the outside, so they are vulnerable to fingerprints. The impact of pollution caused by, fingerprints, dust, etc. Therefore, an antifouling layer is provided for the purpose of easily preventing pollution from the external environment or easily removing attached contaminants (for example, Patent Document 1 and Patent Document 2).

These optical films are temporarily attached to a surface protection film in order to prevent scratches or contamination in the state before use such as processing or transportation (for example, Patent Document 3). The surface protection film is provided with an adhesive layer on the main surface of the film substrate, and is adhered to the surface of the protection object through the adhesive layer. The surface protection film is a step material, so it is required to have low adhesiveness and be easy to peel from the adherend, and no glue residue is generated on the adherend. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-69008 [Patent Document 2] Japanese Patent Laid-Open No. 2017-117666 [Patent Document 3] Japanese Patent Laid-Open No. 2008-151996

[The problem to be solved by the invention]

The antifouling layer easily repels moisture or oil. Therefore, when the surface protective film is pasted on the surface of the antifouling layer, the adhesion between the antifouling layer and the adhesive layer is low. It is in the state before the optical film is used for transportation or processing. It is easy to cause defects such as peeling of the surface protection film from the surface of the optical film, or mixing of air bubbles at the bonding interface. Especially when the antifouling properties of the antifouling layer are high, this tendency is significant. On the other hand, if the adhesive force of the adhesive layer is increased in order to improve the adhesion of the surface protection film, contamination caused by the residual glue on the surface of the antifouling layer is likely to occur when the surface protection film is peeled from the optical film. [Technical solution to solve the problem]

The inventors of the present invention found that by using a surface protective film with a specific adhesive layer, sufficient adhesion to the antifouling layer with high antifouling properties is achieved, and residual glue when the surface protective film is peeled is less likely to occur.

The present invention relates to an optical film with a protective film, comprising: an optical film having an antifouling layer as the outermost layer; and a surface protection film temporarily attached to the antifouling layer of the optical film. The surface protection film is provided with an adhesive layer on the film substrate, and the antifouling layer of the optical film is in contact with the adhesive layer of the surface protection film.

The water contact angle of the antifouling layer of the optical film is more than 100°. The thickness of the adhesive layer of the surface protection film is preferably 16 μm or more. In the optical film with a protective film of the present invention, the adhesion between the antifouling layer of the optical film and the adhesive layer of the surface protective film does not reach 0.07 N/50 mm.

The surface hardness of the adhesive layer is preferably 600 kPa or less. The dynamic friction coefficient of the antifouling layer is preferably 0.15 or less. As an example of the material of the antifouling layer, a fluorine-based resin having a perfluoropolyether skeleton can be cited.

The optical film may have at least one inorganic film between the film base material and the antifouling layer. The inorganic film may be an anti-reflection layer including a plurality of inorganic films with different refractive indexes.

The optical film may have a hard coat layer on the film substrate. The hard coating on the film substrate may be an anti-glare hard coating containing fine particles. The arithmetic average roughness of the surface of the antifouling layer of the optical film can be 0.1 ~ 2.5 μm. [Effects of Invention]

The optical film with a protective film of the present invention has excellent antifouling properties because the water contact angle of the antifouling layer provided on the outermost surface of the optical film is 100° or more. In addition, since the adhesive force between the optical film and the surface protection film is in a specific range, it is possible to prevent the mixing of bubbles to the bonding interface or the peeling of the surface protection film before use of the optical film.

The optical film with a protective film of the present invention is a laminate of an optical film and a surface protective film. The optical film has at least an antifouling layer on one main surface of the film substrate, and the surface protection film has an adhesive layer on the film substrate. The antifouling layer is arranged on the outermost surface of the optical film. In the optical film with protective film, the adhesive layer of the surface protective film is pasted on the antifouling layer of the optical film.

1 is a cross-sectional view showing the structure of an anti-reflection film 100 with a protective film in which a surface protective film 70 is temporarily attached to the surface of the anti-reflection film 10 as an embodiment of an optical film. The anti-reflection film 10 includes an anti-reflection layer 3 on the film substrate 1 and an anti-fouling layer 4 on the anti-reflection layer 3. The surface protection film 70 includes an adhesive layer 8 on the film substrate 7. The anti-fouling layer 4 is the most surface layer of the anti-reflective film 10, and an adhesive layer 8 of the surface protective film 70 is pasted on the anti-fouling layer 4.

Hereinafter, according to the preferred form of the anti-reflection film with protective film shown in FIG. 1, the materials, characteristics, etc. of each layer will be described in sequence.

[Anti-reflective film] The anti-reflective film 10 includes an anti-fouling layer 4 as the outermost layer on the first main surface of the film substrate 1, and an anti-reflective layer 3 between the film substrate 1 and the anti-fouling layer 4. The hard coat layer 2 can be provided on the first main surface of the film substrate 1.

＜Film base material＞ As the film substrate 1, for example, a transparent film is used. The visible light transmittance of the transparent film is preferably 80% or more, more preferably 90% or more. As the resin material constituting the transparent film, for example, a resin material excellent in transparency, mechanical strength, and thermal stability is preferable. Specific examples of the resin material include: cellulose resins such as triacetate cellulose, polyester resins, polyether-based resins, poly-based resins, polycarbonate-based resins, polyamide-based resins, and polyamide resins. Imidine resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins And mixtures of these.

The film substrate 1 may contain antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, fillers, pigments, surfactants, antistatic agents, and the like. On the surface of the film substrate, there can be an easy-adhesive layer, an easy-slip layer, an anti-adhesion layer, an antistatic layer, an anti-reflection layer, an anti-oligomer layer, etc.

The thickness of the film substrate is not particularly limited. From the viewpoints of strength, handleability, etc., workability, thin layer properties, etc., it is preferably about 5 to 300 μm, more preferably 10 to 250 μm, and still more preferably 20～200 μm.

(Hard coating) The surface of the film substrate 1 is preferably provided with a hard coat layer 2. By providing the hard coat layer 2 on the side where the anti-reflection layer 3 of the film substrate 1 is formed, the surface hardness of the anti-reflection film or the mechanical properties such as scratch resistance can be improved.

Examples of the curable resin constituting the hard coat layer 2 include thermosetting resins, ultraviolet curing resins, electron beam curing resins, and the like. Examples of the types of curable resins include polyester, acrylic, urethane, acrylic urethane, amide, silicone, silicate, and cyclic Various resins such as oxygen-based, melamine-based, oxetane-based, and urethane acrylate-based resins. One or two or more of these curable resins can be appropriately selected and used.

Among them, acrylic resins, urethane acrylate resins, and epoxy resins are preferred in terms of high hardness, UV curability, and excellent productivity. Among them, acrylic amine is preferred. Carbamate-based resin. UV-curing resins include UV-curing monomers, oligomers, polymers, etc. As for UV-curable resins that are preferably used, for example, resins with UV-polymerizable functional groups can be cited. Among them, acrylic monomers or oligomers containing 2 or more, especially 3-6 functional groups can be cited. As a component of the resin.

In order to provide the anti-reflection film with anti-glare properties and anti-glare properties, the hard coat layer 2 may be provided with anti-glare properties. As an antiglare hard coat layer, for example, a hard coat layer in which fine particles are dispersed in the above-mentioned curable resin matrix can be cited. As the fine particles dispersed in the resin matrix, various metal oxide fine particles such as silicon dioxide, aluminum oxide, titanium oxide, zirconium oxide, calcium oxide, tin oxide, indium oxide, cadmium oxide, antimony oxide, and glass can be used without particular limitation. Particles, crosslinked or uncrosslinked organic particles containing various transparent polymers such as polymethylmethacrylate, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, polycarbonate, etc. , Organosilicon particles and other transparent particles. The average particle diameter of the fine particles is preferably 20 to 5000 nm, more preferably 2000 to 4000 nm. The ratio of the fine particles is not particularly limited, and it is preferably 2-40 parts by weight, more preferably 3-20 parts by weight relative to 100 parts by weight of the base resin. When the average particle size and content of the fine particles are within the above-mentioned range, unevenness suitable for light scattering can be formed on the surface of the hard coat layer 2, thereby imparting good anti-glare properties.

The thickness of the anti-reflection layer 3 and the anti-fouling layer 4 formed on the hard coating layer 2 is small, so the surface shape of the anti-fouling layer 4 depends on the surface shape of the hard coating layer 2. As described later, the arithmetic average roughness of the surface of the antifouling layer 4 is preferably 0.1-2.5 μm. In order to make the arithmetic average roughness of the surface of the antifouling layer 4 within the above range, the arithmetic average roughness of the hard coat layer 2 is preferably 0.1-2.5 μm. The arithmetic average roughness Ra is calculated from an observation image of 100 μm×100 μm using a laser microscope, according to JIS B0601:1994. By adjusting the particle size or content of the fine particles contained in the hard coat layer, the uneven shape of the surface of the hard coat layer 2 can be adjusted.

The hard coat layer can be formed, for example, by coating a solution containing a curable resin on a transparent film. It is preferable to prepare an ultraviolet polymerization initiator in the solution for forming the hard coat layer. In order to form an anti-glare hard coat layer containing fine particles, it is preferable to apply a solution containing the above fine particles in addition to the curable resin on the transparent film. The solution may contain additives such as leveling agents, thixotropic agents, and antistatic agents. In the formation of the anti-glare hard coating, since the solution contains a thixotropic agent (for example, silica, mica, etc. particles with a particle size of 0.1 μm or less), it can be easily formed on the surface of the hard coating by using protruding particles. Convex structure.

The thickness of the hard coat layer 2 is not particularly limited. In order to achieve high hardness, it is preferably 0.5 μm or more, more preferably 1 μm or more. In consideration of the ease of formation by coating, the thickness of the hard coat layer is preferably 15 μm or less, more preferably 12 μm or less, and still more preferably 10 μm or less.

Before forming the anti-reflection layer 3 on the hard coat layer 2, for the purpose of further improving the adhesion between the hard coat layer 2 and the anti-reflection layer 3, the surface treatment of the hard coat layer 2 may be performed. Examples of surface treatments include surface modification treatments such as corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, alkali treatment, acid treatment, and treatment with a coupling agent. As the surface treatment, vacuum plasma treatment can be performed. The surface roughness of the hard coating can also be adjusted by vacuum plasma treatment. For example, if vacuum plasma treatment is performed with high discharge power, the Ra of the hard coat surface tends to increase. The discharge power of vacuum plasma treatment (for example, argon plasma treatment) is about 0.5 to 10 kW, preferably about 1 to 5 kW.

＜Anti-reflective layer＞ Generally, with regard to the anti-reflection layer, the optical film thickness (the product of the refractive index and the thickness) of the film is adjusted in such a way that the inverted phases of the incident light and the reflected light cancel each other. The use of a multi-layer laminate of a plurality of thin films with different refractive indices can reduce the reflectance in the broad wavelength range of visible light. As the material of the film constituting the anti-reflection layer 3, metal oxides, nitrides, fluorides, etc. can be cited. The anti-reflection layer 3 is preferably an alternate laminate of a high refractive index layer and a low refractive index layer. In order to reduce the reflection at the interface with the anti-fouling layer, the film 34 provided as the outermost layer of the anti-reflection layer 3 is preferably a low refractive index layer.

Regarding the high refractive index layers 31 and 33, the refractive index is, for example, 1.9 or more, preferably 2.0 or more. Examples of high refractive index materials include titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, indium tin oxide (ITO), antimony-doped tin oxide (ATO), and the like. Among them, titanium oxide or niobium oxide is preferred. Regarding the low refractive index layers 32 and 34, the refractive index is 1.6 or less, preferably 1.5 or less, for example. Examples of low refractive index materials include silicon oxide, titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Among them, silicon oxide is preferred. It is particularly preferable to alternately laminate niobium oxide (Nb ₂ O ₅ ) films 31 and 33 as high refractive index layers and silicon oxide (SiO ₂ ) films 32 and 34 as low refractive index layers. In addition to the low refractive index layer and the high refractive index layer, a medium refractive index layer with a refractive index of about 1.6 to 1.9 can also be provided.

The film thickness of the high refractive index layer and the low refractive index layer is about 5 to 200 nm, and preferably about 15 to 150 nm. According to the refractive index, the layer structure, etc., the film thickness of each layer may be designed so that the reflectance of visible light becomes small. For example, as a laminated structure of a high refractive index layer and a low refractive index layer, a high refractive index layer 31 with an optical film thickness of about 25 nm to 55 nm from the film substrate side, and an optical film thickness of about 35 nm to 55 nm can be cited. The low refractive index layer 32, the high refractive index layer 33 with an optical film thickness of about 80 nm to 240 nm, and the low refractive index layer 34 with an optical film thickness of about 120 nm to 150 nm are composed of four layers.

The anti-reflection layer 3 is preferably provided with a primer layer 30 on the surface in contact with the hard coat layer 2 and a high refractive index layer and a low refractive index layer thereon.

Examples of the material constituting the primer layer 30 include metals such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, tungsten, aluminum, zirconium, and palladium; alloys of these metals; these metals The oxide, fluoride, sulfide or nitride; etc. Among them, the material of the primer layer is preferably oxide, particularly preferably silicon oxide. Since silicon oxide has a low refractive index, it can reduce the reflection of visible light at the interface between the hard coat layer 2 and the primer layer 30.

The primer layer 30 is preferably an inorganic oxide layer with an oxygen content less than the stoichiometric composition. Among inorganic oxides of non-stoichiometric composition, silicon oxide represented by the composition formula SiOx (0.5≦x<2) is preferred.

The thickness of the primer layer 30 is, for example, about 1-20 nm, preferably 3-15 nm. When the film thickness of the primer layer is in the above-mentioned range, it is possible to balance the adhesion with the hard coat layer 2 and high light transmittance.

The film forming method of the film constituting the anti-reflection layer 3 is not particularly limited, and may be any of a wet coating method and a dry coating method. In terms of being able to form a film with a uniform film thickness, dry coating methods such as vacuum evaporation, CVD, sputtering, and electron beam evaporation are preferred. Among them, the sputtering method is preferred in terms of excellent film thickness uniformity and easy formation of a dense film.

In the sputtering method, a roll-to-roll method can be used to transport a long film substrate in one direction (longitudinal direction) while continuously forming a thin film. In the sputtering method, an inert gas such as argon and a reactive gas such as oxygen as needed are introduced into the chamber while forming a film. The film formation of the oxide layer using the sputtering method can be implemented by either the method using an oxide target and the reactive sputtering using a metal target. In order to form a metal oxide film at a high rate, reactive sputtering using a metal target is preferred.

＜Antifouling layer＞ The anti-reflection film 10 has an antifouling layer 4 as the outermost layer on the first main surface of the film substrate 1. With the anti-fouling layer provided on the outermost surface, the influence of pollution (fingerprints, fingerprints, dust, etc.) from the external environment can be reduced, and it becomes easy to remove the contaminants attached to the surface. In order to improve the anti-pollution properties and the removal of pollutants, the water contact angle of the anti-fouling layer 4 is preferably 100° or more, more preferably 102° or more, and still more preferably 105° or more. The larger the water contact angle, the higher the water repellency, and there is a tendency to improve the anti-adhesion effect of pollutants or the removal of pollutants.

On the other hand, if the water contact angle is too large, the wettability will be low. Therefore, when a surface protective film is attached to the surface of the antifouling layer, the adhesion to the adhesive layer will be low, and sometimes the protective film during transportation/processing may occur. Defects such as peeling, or mixing of bubbles into the adhesive interface. Therefore, the water contact angle of the antifouling layer 4 is preferably 130° or less, more preferably 125° or less, and still more preferably 120° or less.

The dynamic friction coefficient of the antifouling layer 4 is preferably 0.15 or less, more preferably 0.13 or less, and still more preferably 0.11 or less. The smaller the coefficient of dynamic friction, the better the smoothness, the less likely to be scratched on the surface, and the tendency to improve scratch resistance. On the other hand, if the dynamic friction coefficient is too small, it may hinder the transportation or handling of the film. Therefore, the dynamic friction coefficient of the antifouling layer 4 is preferably 0.01 or more, more preferably 0.03 or more, and still more preferably 0.05 or more.

The coefficient of dynamic friction depends on the material forming the antifouling layer and the surface shape of the antifouling layer. In order to make the dynamic friction coefficient within the above range, the arithmetic average roughness of the antifouling layer 4 is preferably 0.1 to 2.5 μm, more preferably 0.5 to 2.2 μm, and still more preferably 0.8 to 1.8 μm.

Since the anti-reflective layer 3 and the anti-fouling layer 4 have a small thickness, the surface of the anti-fouling layer 4 is easily formed with uneven shapes reflecting the surface shape of the hard coat layer 2. Therefore, in order to make the arithmetic average roughness of the surface of the antifouling layer 4 into the above-mentioned range, it is preferable to include particles in the hard coat layer 2 to form surface irregularities. In addition, the surface shape may be adjusted by performing surface treatment such as vacuum plasma treatment on the hard coat layer 2.

In order to maintain the anti-reflection properties of the anti-reflection layer 3, it is preferable that the difference in refractive index between the anti-fouling layer 4 and the low-refractive index layer 34 on the outermost surface of the anti-reflection layer 3 be small. The refractive index of the antifouling layer 4 is preferably 1.6 or less, more preferably 1.55 or less.

The material of the antifouling layer 4 is preferably a fluorine-containing compound. The fluorine-containing compound imparts antifouling properties and can also contribute to lowering the refractive index. Among them, in terms of excellent water repellency and high antifouling properties, a fluorine-based polymer containing a perfluoropolyether skeleton is preferred. From the standpoint of improving antifouling properties, a perfluoropolyether having a main chain structure that can be rigidly arranged is particularly preferred. As the structural unit of the main chain skeleton of the perfluoropolyether, a branched perfluorooxyalkylene group having 1 to 4 carbon atoms is preferred. For example, perfluorooxymethylene (-CF ₂ O-) , Perfluorooxyethylene (-CF ₂ CF ₂ O-), Perfluorooxypropylene (-CF ₂ CF ₂ CF ₂ O-), Perfluorooxyisopropyl (-CF(CF ₃ )CF ₂ O-) and so on.

The antifouling layer can be formed by a wet method such as a reverse coating method, a bar coating method, or a gravure coating method, or a dry method such as a CVD method. The thickness of the antifouling layer is usually about 2-50 nm. There is a tendency that the greater the thickness of the antifouling layer 4, the greater the water contact angle. In order to make the water contact angle of the antifouling layer 4 100° or more, the thickness of the antifouling layer 4 is preferably 7 nm or more.

[Surface protective film] The surface protection film 70 includes an adhesive layer 8 on one main surface of the film substrate 7. By adhering the surface protection film 70 to the surface of the anti-reflection film 10, the surface of the anti-reflection film 10 can be protected during transportation, processing, and other manufacturing processes to prevent scratches or contamination of the anti-fouling layer 4.

＜Film base material＞ The surface protection film 70 is a step material for protecting the surface of the anti-reflection film 10 and is peeled off when the anti-reflection film 10 is used. Therefore, as long as the film substrate 7 of the surface protection film 70 has mechanical strength for protecting the surface, the material or thickness thereof is not particularly limited. As the film base material 7, it is preferable to use the resin material exemplified in the foregoing regarding the film base material 1 of the antireflection film 10, or a film base material having a thickness.

＜Adhesive layer＞ From the viewpoints of improving the adhesion to the antifouling layer with a large water contact angle, suppressing peeling of the surface protection film, or mixing of air bubbles to the adhesion interface, the thickness of the adhesive layer 8 is preferably 16 μm or more, more It is preferably 18 μm or more, more preferably 20 μm or more. From the viewpoint of increasing the hardness of the adhesive layer and reducing the residual glue, the thickness of the adhesive layer 8 is preferably 50 μm or less, more preferably 40 μm or less, and still more preferably 35 μm or less.

The composition of the adhesive constituting the adhesive layer 8 is not particularly limited, and acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate/vinyl chloride can be appropriately selected and used. Copolymers, modified polyolefins, epoxy-based, fluorine-based, natural rubber, synthetic rubber and other rubber-based polymers are used as adhesives for the base polymer. Especially in terms of excellent adhesiveness and optical transparency, it is preferable to use an acrylic adhesive having an acrylic polymer as a base polymer.

As the acrylic base polymer of the acrylic adhesive, a polymer having a monomer unit of alkyl (meth)acrylate as the main skeleton is preferably used. In addition, in this specification, "(meth)acrylic acid" means acrylic acid and/or methacrylic acid.

As the alkyl (meth)acrylate, an alkyl (meth)acrylate whose alkyl group has 1 to 20 carbon atoms is suitably used. Examples include: methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, (meth)acrylate ) Tert-butyl acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, ( 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, (meth)acrylic acid Decyl ester, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridecyl (meth)acrylate, (meth) Myristyl acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecyl (meth)acrylate Ester, stearyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, aralkyl (meth)acrylate, etc.

The content of the alkyl (meth)acrylate relative to the total amount of monomer components constituting the acrylic polymer is preferably 40% by weight or more, more preferably 50% by weight or more, and still more preferably 60% by weight or more. The acrylic polymer may be a copolymer of a plurality of alkyl (meth)acrylates. The arrangement of the monomer units may be random or block.

The acrylic polymer preferably contains a monomer component having a crosslinkable functional group as a copolymer component. Examples of the monomer having a crosslinkable functional group include a hydroxyl group-containing monomer or a carboxyl group-containing monomer. Among these, it is preferable to contain a hydroxyl-containing monomer as a copolymerization component. The hydroxyl group or the carboxyl group becomes the reaction point with the crosslinking agent mentioned later. By introducing a cross-linked structure into the base polymer, the cohesive force of the adhesive is improved, and it shows a moderate adhesive force to the adherend, and the surface protection film can be easily peeled from the adherend, and it can suppress residual glue, etc. The tendency to cause pollution.

Examples of hydroxyl-containing monomers include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxy (meth)acrylate Hexyl ester, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, or (4-hydroxymethylcyclohexyl)methyl acrylate, etc. . Examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like.

In addition to the above-mentioned acrylic polymers, acid anhydride group-containing monomers, caprolactone adducts of acrylic acid, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, etc. can also be used as comonomer components. In addition, as the modifying monomer, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine can also be used. , Vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxamides, styrene, α-methylstyrene, N-vinylcaprolactone Vinyl monomers such as amines; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth) Acrylate, polypropylene glycol (meth)acrylate, methoxy glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate and other glycol-based acrylate monomers; (meth)acrylic acid Acrylate monomers such as tetrahydrofurfuryl ester, fluoro(meth)acrylate, organosilicon (meth)acrylate, or 2-methoxyethyl acrylate.

The ratio of the comonomer component in the acrylic polymer is not particularly limited. For example, when a hydroxyl-containing monomer or a carboxyl-containing monomer is used as the comonomer component for the purpose of introducing crosslinking points, the hydroxyl-containing monomer The total content of the monomer and the carboxyl group-containing monomer is preferably about 1 to 20%, more preferably about 2 to 15% with respect to the total amount of monomer components constituting the acrylic polymer.

The above-mentioned monomer components are polymerized by various known methods such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. to obtain acrylic polymers. From the viewpoint of the balance of properties such as adhesive force and retention force of the adhesive, or the viewpoint of cost, the solution polymerization method is preferred. As a solvent for solution polymerization, ethyl acetate, toluene, etc. can be used. The solution concentration is usually about 20 to 80% by weight. As the polymerization initiator, various well-known polymerization initiators such as azo-based and peroxide-based can be used. In order to adjust the molecular weight, a chain transfer agent can be used. The reaction temperature is usually about 50 to 80°C, and the reaction time is usually about 1 to 8 hours.

The molecular weight of the acrylic polymer is appropriately adjusted so that the adhesive layer 8 has the desired adhesive force. For example, the weight average molecular weight in terms of polystyrene is about 50,000 to 2 million, preferably about 70,000 to 1.8 million, and more It is preferably about 100,000 to 1.5 million, and more preferably about 200,000 to 1 million. Furthermore, when a cross-linked structure is introduced into the acrylic base polymer, it is preferable that the molecular weight of the polymer before the introduction of the cross-linked structure is in the above range.

For the purpose of adjusting the adhesive force of the adhesive layer 8, a cross-linked structure can be introduced into the base polymer. For example, for acrylic polymers, a crosslinking agent is added to the solution after polymerization, and heating is performed as needed to introduce a crosslinked structure. Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate compounds Department of crosslinking agent and so on. Among them, in terms of high reactivity with the hydroxyl group or carboxyl group of the acrylic polymer and easy introduction of a crosslinked structure, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred. These crosslinking agents react with functional groups such as hydroxyl or carboxyl groups introduced into the polymer to form a crosslinked structure.

As the isocyanate-based crosslinking agent, a polyisocyanate having two or more isocyanate groups per molecule can be used. Examples of isocyanate-based crosslinking agents include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; cyclopentyl diisocyanate, cyclohexyl diisocyanate, and isophorone diisocyanate Alicyclic isocyanates; 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and other aromatic isocyanates; trimethylolpropane/toluene diisocyanate 3 Polymer adducts (e.g. "Coronate L" manufactured by Tosoh), trimethylolpropane/hexamethylene diisocyanate trimeric adducts (e.g. "Coronate HL" manufactured by Tosoh), benzodiazepines Trimethylolpropane adduct of methyl diisocyanate (e.g. "Takenate D110N" manufactured by Mitsui Chemicals, isocyanurate of hexamethylene diisocyanate (e.g. "Coronate HX" manufactured by Tosoh)) and other isocyanate Into things etc.

As the epoxy-based crosslinking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. The epoxy group of the epoxy-based crosslinking agent may be a glycidyl group. Examples of epoxy-based crosslinking agents include: N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-di Glycidyl amino methyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene two Alcohol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, three Methylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, triglycidyl-tris(2-hydroxyethyl) isocyanurate, resorcinol diglycidyl Glycidyl ether, bisphenol-S-diglycidyl ether, etc. As the epoxy-based crosslinking agent, commercially available products such as "DENACOL" manufactured by Nagase ChemteX, "Tetrad X" and "Tetrad C" manufactured by Mitsubishi Gas Chemical can be used.

The crosslinking structure is introduced by adding a crosslinking agent to the acrylic polymer after polymerization. The amount of crosslinking agent used can be adjusted appropriately according to the composition, or molecular weight, and target adhesion characteristics of the polymer. In order to impart a moderate cohesive force to the adhesive, the peeling force when the protective film is peeled from the adherend is adjusted to an appropriate range. The amount of crosslinking agent used is preferably 1.5 parts by weight or more relative to 100 parts by weight of the acrylic polymer , More preferably, it is 2 parts by weight or more, and still more preferably 2.5 parts by weight or more. In order to impart proper adhesion to the adherend, the amount of crosslinking agent used relative to 100 parts by weight of the acrylic polymer is preferably 12 parts by weight or less, more preferably 10 parts by weight or less, and even more preferably 8 parts by weight The following.

With the increase in the amount of crosslinking agent used, the hardness of the adhesive layer tends to increase and the viscosity decreases. Therefore, with the increase in the amount of the crosslinking agent used, there is a tendency to suppress the residual glue on the surface of the antifouling layer 4 when the surface protective film 70 is peeled from the antireflection film 10. On the other hand, when the amount of crosslinking agent used increases, the hardness of the adhesive layer increases excessively and the adhesiveness decreases. Therefore, problems such as peeling of the protective film during transportation/processing or mixing of bubbles to the adhesive interface may occur. Especially when the water contact angle of the antifouling layer 4 is 100° or more, the adhesive is difficult to wet and spread on the antifouling layer. Therefore, when the amount of the crosslinking agent used is too large, the adhesion is likely to decrease. In addition, when the usage amount of the crosslinking agent increases, the unreacted crosslinking agent oozes out on the surface of the adhesive layer 8 and sometimes causes the surface of the antifouling layer 4 to be contaminated.

From the viewpoint of setting the hardness of the adhesive layer to an appropriate range and suppressing the contamination of the antifouling layer caused by the crosslinking agent, it is preferable to adjust the crosslinkable functional group of the acrylic polymer and the crosslinking agent. The ratio of reactive functional groups. The addition amount of the crosslinking agent is preferably adjusted so that the molar equivalent of the reactive functional group of the crosslinking agent becomes 0.3 to 1.2 times the molar equivalent of the crosslinkable functional group of the acrylic polymer. For example, when an isocyanate-based crosslinking agent is used, it is preferable to adjust the amount of the crosslinking agent so that the molar equivalent of the isocyanate group becomes 0.3 to 1.2 times the molar equivalent of the hydroxyl group of the polymer. When an epoxy-based crosslinking agent is used, it is preferable to adjust the amount of the crosslinking agent so that the molar equivalent of the epoxy group becomes 0.3 to 1.2 times the molar equivalent of the carboxyl group of the polymer. The molar equivalent of the reactive functional group of the crosslinking agent is more preferably 0.4 to 1.0 times the molar equivalent of the crosslinkable functional group of the polymer, and more preferably 0.5 to 0.9 times.

The adhesive composition used to form the adhesive layer contains a base polymer and a crosslinking agent and solvent as needed. The adhesive composition may contain polymerization catalysts, crosslinking catalysts, silane coupling agents, tackifiers, plasticizers, softeners, anti-deterioration agents, fillers, colorants, Additives such as ultraviolet absorbers, antioxidants, surfactants, and antistatic agents.

By roll coating, roll coating, gravure coating, reverse coating, roll brushing, spraying, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating , Die mouth coating, etc., apply the adhesive composition on the substrate, and dry and remove the solvent as needed to form an adhesive layer. As the drying method, an appropriate method can be suitably adopted. The heating and drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and still more preferably 70°C to 170°C. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, still more preferably 10 seconds to 10 minutes, particularly preferably 10 seconds to 5 minutes.

When the adhesive composition contains a crosslinking agent, it is preferable to perform crosslinking by heating or aging simultaneously with the drying of the solvent or after the drying of the solvent. When the adhesive composition contains the monomer components of the base polymer, it is preferably polymerized by heating or aging. The heating temperature or heating time is appropriately set according to the type of monomer or crosslinking agent used, and is usually about 1 minute to 7 days in the range of 20°C to 160°C. The heating for drying and removing the solvent can also be used for polymerization or crosslinking heating.

By laminating the adhesive layer 8 on the film substrate 7, a surface protection film is obtained. The adhesive layer 8 can be directly formed on the film substrate 7, or an adhesive layer formed in a sheet shape on other substrates can be transferred to the film substrate 7. It is preferable that the surface protection film is attached with a separator in order to protect the surface of the adhesive layer 8 during the period until it is adhered to an anti-reflection film or the like.

As described above, from the viewpoint of ensuring the adhesion of the antifouling layer with a large water contact angle, the thickness of the adhesive layer 8 provided on the film substrate 7 is preferably 18 μm or more. In addition, from the viewpoint of further improving the adhesion to the antifouling layer, the surface hardness of the adhesive layer 8 is preferably 600 kPa or less, more preferably 400 kPa or less, still more preferably 300 kPa or less, particularly preferably Below 200 kPa. On the other hand, from the viewpoint of suppressing the residual glue on the antifouling layer, the surface hardness of the adhesive layer 8 provided on the film substrate 7 is preferably 20 kPa or more, more preferably 30 kPa or more, and more It is preferably 40 kPa or more, particularly preferably 50 kPa or more. The surface hardness of the adhesive layer is measured by nanoindentation.

From the standpoint of ensuring proper adhesion to the antifouling layer with a large water contact angle and imparting proper hardness to inhibit contamination of the antifouling layer caused by the transfer of the adhesive, the gel component of the adhesive layer 8 The rate is preferably 85-95%. When the gel fraction of the adhesive layer 8 is too large, the wettability to the adherend decreases, and the adhesive strength may become insufficient. On the other hand, if the gel fraction is too small, the hardness of the adhesive decreases, which sometimes causes contamination of the antifouling layer. The gel fraction can be determined in the form of insoluble components that are insoluble in solvents such as ethyl acetate. Specifically, the insoluble components of the adhesive layer after immersing in ethyl acetate at 23°C for 7 days can be compared with the test before immersion. Calculate the weight fraction of the sample (unit: weight%). Generally, the gel fraction of a polymer is equal to the degree of cross-linking. The more cross-linked part of the polymer, the greater the gel fraction.

From the viewpoint of imparting moderate hardness to the adhesive layer 8 and reducing the peeling force when the surface protective film 70 is peeled from the anti-reflection film 10, the storage elastic modulus G'at 23° C. of the adhesive layer 2 is preferably 5.0×10 ⁴ Pa or more, more preferably 7.5×10 ⁴ Pa or more, and still more preferably 1.0×10 ⁵ Pa or more. When the storage elastic modulus of the adhesive layer 8 is too large, the wettability of the antifouling layer is reduced, and sometimes the adhesive force becomes insufficient. Therefore, the storage elastic modulus G′ at 23° C. of the adhesive layer 2 is preferably 5.0×10 ⁶ Pa or less, more preferably 2.5×10 ⁶ Pa or less, and still more preferably 1.0×10 ⁶ Pa or less. The storage elastic modulus G'is calculated as follows: using a dynamic viscoelasticity measuring device (for example, "ARES" manufactured by Rheometrics), at a frequency of 1 Hz, a temperature range of -70°C to 150°C, and a heating rate of 5°C/min. The viscoelasticity is measured in the shear mode to obtain it.

[Layer of anti-reflective film and surface protective film] The adhesive layer 8 of the surface protective film 70 is stuck on the anti-fouling layer 4 of the anti-reflective film 10 to obtain the anti-reflective film 100 with the protective film. The sticking method is not particularly limited, and for example, a usual sticking method using a roll laminator can be used.

The adhesion force between the anti-reflection film 10 and the surface protection film 70 is preferably less than 0.07 N/50 mm. When the adhesive force of the two is less than 0.07 N/50 mm, it can prevent the pollution caused by the residual glue on the surface of the antifouling layer 4 after the surface protective film is peeled off. From the viewpoint of more reliably preventing contamination caused by adhesive residue, etc., the adhesion between the anti-reflection film 10 and the surface protective film 70 is more preferably 0.06 N/50 mm or less, and more preferably 0.05 N/50 mm or less. The subsequent force is the peel force when the 180° peel test is performed at a tensile speed of 0.3 m/min.

From the viewpoint of preventing the mixing of air bubbles to the bonding interface or peeling off of the surface protection film before the use of the anti-reflection film, the adhesive force between the anti-reflection film 10 and the surface protection film 70 is preferably 0.01 N/50 mm or more, and more Preferably, it is 0.02 N/50 mm or more. As mentioned above, by adjusting the usage amount of the crosslinking agent in the adhesive composition used in the formation of the adhesive layer 8, the hardness of the adhesive layer 8 is set to an appropriate range, so that the adhesive force can be adjusted to Within the above range.

[Applications other than anti-reflective film] The example of sticking the surface protective film 70 on the surface of the anti-reflective film 10 provided with the antifouling layer 4 on the outermost surface will be described. However, the optical film as the protection object of the surface protective film 70 only needs to have water on the outermost surface of the film substrate. An anti-fouling layer with a contact angle of 100° or more is sufficient, but it is not limited to an anti-reflection film.

The optical film may be an antifouling film having only an antifouling layer on the film substrate. In addition, the optical film may be a functional optical film having various functional layers between the film substrate and the antifouling layer. The antifouling film or the functional optical film may have a hard coat layer, an anti-glare layer, or the like on the film substrate.

Examples of functional optical films include conductive films used for position detection of touch panels, shading films pasted on window glass, or display windows, or heat/insulation films. Examples of the functional layer of such a functional optical film include inorganic films such as metals or metal compounds (metal or semimetal oxides, nitrides, carbides, sulfides, fluorides, etc.). The functional layer may be conductive, insulating, or semiconductor. Example

Examples are given below to illustrate the present invention in more detail, but the present invention is not limited to the following examples.

[Production of anti-reflective film] <Anti-reflective film A> 50 parts by weight of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical "VISCOAT♯300") as a binder resin and a urethane acrylate prepolymer (new Nakamura Chemical Industry "UA-53H-80BK") 50 parts by weight; Organic silicon particles ("TOSPEARL130" manufactured by Momentive Performance Materials Japan, weight average particle size: 3 μm) 3.5 parts by weight; Synthetic smectite as an organic clay ( Co-op Chemical Co., Ltd. manufactured "Lucentite SAN") 2 parts by weight; photopolymerization initiator (BASF manufactured "Irgacure907") 3 parts by weight; and leveling agent (DIC manufactured "PC4100", solid content 10 %) 0.2 parts by weight were mixed, and diluted with a toluene/cyclopentanone mixed solvent (weight ratio 70/30) to prepare a composition for forming a hard coat layer with a solid content of 33% by weight. In addition, the organoclay was diluted with toluene so that the solid content might become 6 wt%. Using a comma coater (registered trademark), the composition was applied to a 40 μm thick triacetyl cellulose film ("KC4UA" manufactured by Konica Minolta), and heated at 80°C for 1 minute. Then, a high-pressure mercury lamp was used to irradiate ultraviolet light with a cumulative light intensity of 300 mJ/cm ^{2 to} harden the coating layer to form an anti-glare hard coating with a thickness of 6.3 μm.

(Formation of anti-reflective layer) Introduce the triacetyl cellulose film with the hard coat layer into the roll-to-roll sputtering film forming device, while the film is running, the surface where the anti-glare hard coat layer is formed is bombarded After (plasma treatment with Ar gas), a 3.5 nm SiO _x layer (x<2) is formed as an adhesion improving layer, and a 10.1 nm Nb ₂ O ₅ layer and a 27.5 nm SiO ₂ layer are sequentially formed on it Layer, 105.0 nm Nb ₂ O ₅ layer and 83.5 nm SiO ₂ layer. The adhesion improvement layer and the SiO ₂ layer were formed using a Si target, and the Nb ₂ O ₅ layer was formed using a Nb target. In the formation of the SiO ₂ layer and the formation of the Nb ₂ O ₅ layer, the amount of oxygen introduced is adjusted in a way that the film formation mode maintains the transition zone by the plasma luminescence monitoring (PEM) control.

(Formation of antifouling layer) Coat the fluorine resin solution (antifouling material 1) containing perfluoroether containing -(CF ₂ -CF ₂ -O)- and -(CF ₂ -O)- in the backbone of the main chain Spread on the surface SiO ₂ layer of the anti-reflective layer so that the thickness after drying becomes 9 nm to form an anti-fouling layer as a topcoat layer.

<Anti-reflection film B, C> The anti-reflection film B and the anti-reflection film C were produced in the same manner as the anti-reflection film A except that the structure of the antifouling layer was different. In the anti-reflective film B, the material of the anti-fouling layer is changed to a fluorine resin solution containing perfluoroether containing -(O-CF(CF ₃ )-CF ₂ )- in the backbone of the main chain (anti-fouling material 2) , The thickness of the anti-fouling layer is set to 6 nm. In the anti-reflective film C, the thickness of the anti-fouling layer was changed to 4 nm.

[Preparation of Adhesive Composition] <Preparation of Adhesive Composition A> 96 parts by weight of 2-ethylhexyl acrylate (2EHA) and 4 parts by weight of hydroxyethyl acrylate (HEA) as monomer components, and 2,2'-azobisisobutyronitrile as a polymerization initiator ( AIBN) 0.2 parts by weight and 150 parts by weight of ethyl acetate were put into a reaction vessel equipped with a thermometer, a stirrer, a cooler, and a nitrogen introduction pipe, and nitrogen was introduced while stirring slowly at 23°C to perform nitrogen substitution. Then, the liquid temperature was maintained at around 65°C, and the polymerization reaction was carried out for 6 hours to obtain an acrylic polymer solution (concentration 40% by weight).

To 250 parts by weight of the acrylic polymer solution (100 parts by weight of the polymer), 73 parts by weight of toluene and 10 parts by weight of acetone were added to dilute to a concentration of 30% by weight. To this solution, as a crosslinking agent, a 75% ethyl acetate solution of toluene diisocyanate trimer adduct of trimethylolpropane (Tosoh Corporation "Coronate L") was added 5.3 parts by weight (solid content 4.0 Parts by weight) and a 0.5% solution of dioctyltin laurate as a crosslinking catalyst ("EMBILIZER OL-1" manufactured by Tokyo Fine Chemical CO., LTD.) 4 parts by weight (0.02 parts by weight of solid content) and stirred, Prepare acrylic adhesive solution A. The isocyanate equivalent of the crosslinking agent in the composition is 0.69 times the hydroxyl equivalent of the polymer.

<Preparation of Adhesive Composition B> Except that the crosslinking agent was changed to 4.0 parts by weight of the isocyanurate body of hexamethylene diisocyanate ("Coronate HX" manufactured by Tosoh Corporation), the same procedure as the preparation of the adhesive composition A was carried out to prepare an acrylic adhesive Agent solution B. The isocyanate equivalent of the crosslinking agent in the composition is 0.73 times the hydroxyl equivalent of the polymer.

<Preparation of Adhesive Composition C> 54 parts by weight of 2-ethylhexyl acrylate as monomer components, 43 parts by weight of vinyl acetate (VAC), 3 parts by weight of acrylic acid (AA), and benzoyl peroxide (BPO) as a polymerization initiator 0.2 parts by weight and 233 parts by weight of ethyl acetate were put into a reaction vessel equipped with a thermometer, a stirrer, a cooler, and a nitrogen introduction tube, and nitrogen was introduced while slowly stirring at 23°C to perform nitrogen substitution. Then, the liquid temperature was maintained at around 65°C, and the polymerization reaction was carried out for 6 hours to prepare an acrylic polymer solution (concentration 30% by weight).

67 parts by weight of methyl ethyl ketone was added to 333 parts by weight of the acrylic polymer solution (100 parts by weight of the polymer) and diluted to a concentration of 25% by weight. To this solution, 10 parts by weight of a tetrafunctional epoxy compound ("Tetrad C" manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent was added and stirred to prepare an acrylic adhesive solution C. The epoxy equivalent of the crosslinking agent in the composition is 1.46 times the carboxy equivalent of the polymer.

[Production of surface protective film] ＜Surface protection film 1＞ Coating the adhesive composition A on the surface of a 38 μm thick polyethylene terephthalate film ("DIAFOIL T100G38" manufactured by Mitsubishi Chemical Co., Ltd.) with an antistatic layer on one side without an antistatic layer, Dry at 130°C for 2 minutes to form an adhesive layer with a thickness of 21 μm. Paste the release surface of the separator (polyethylene terephthalate film with a thickness of 25 μm with silicone release treatment on one side) on the surface of the adhesive layer.

＜Surface protection film 2＞ Except that the adhesive composition B was used instead of the adhesive composition A, the same operation as the production of the surface protection film 1 was performed to produce the surface protection film 2.

＜Surface protection film 3＞ Except that the adhesive composition C was used instead of the adhesive composition A, and the thickness of the adhesive layer was changed to 23 μm, the same operation as the production of the surface protection film 1 was performed to produce the surface protection film 3.

＜Surface protection film 4＞ As the surface protective film 4, a commercially available adhesive film (Sun A.) with an acrylic adhesive layer with a thickness of 15 μm on a polyethylene terephthalate film and a separator temporarily attached to the surface of the adhesive layer was used. Kaken Co., Ltd. manufactured "SAT-2038T10-JSL").

[Production of anti-reflective film with protective film] The separators of the surface protective films 1 to 4 were peeled off, and the adhesive layer of the surface protective film was stuck on the surface of the anti-fouling layer of the anti-reflective films A to C using a roll laminator to produce Example 1 shown in Table 1. 2 and the anti-reflection film with protective film of Comparative Examples 1 to 4.

[Evaluation method] The following measurement and evaluation are carried out in an environment of 23°C and a relative humidity of 50% (hereinafter "standard environment").

＜Water contact angle of anti-reflective film＞ Using a contact angle measuring device (“DMo-701” manufactured by Kyowa Interface Chemical Co., Ltd.), about 5.0 μL of water was dropped on the surface of the anti-fouling layer of the anti-reflective film before the surface protective film was applied. Measure the angle of the tangent line between the surface of the antifouling layer and the end of the drop after 2 seconds of dripping. For Example 1 and Example 2, a protective film was pasted on the surface of the anti-reflective film, and after standing in a constant temperature and humidity chamber with a temperature of 60°C and a relative humidity of 90% for 250 hours, the surface protective film was peeled off and placed in a standard environment again Next, measure the water contact angle of the anti-reflection film (water contact angle after the damp heat test).

之氈，以載荷500 g、速度300 mm/分鐘、長度50 mm之條件沿一個方向擦拭防污層之表面，將摩擦係數(摩擦力/載荷)之平均值作為抗反射膜(防污層)之動摩擦係數。＜Dynamic friction coefficient of anti-reflective film＞ Using a surface performance tester (TriboGear TYPE: 14 manufactured by Shinto Scientific), 10 mm is used as a sliding sheet

The felt, with a load of 500 g, a speed of 300 mm/min, and a length of 50 mm, wipe the surface of the anti-fouling layer in one direction, and use the average value of the friction coefficient (friction force/load) as the anti-reflective film (anti-fouling layer) The coefficient of dynamic friction.

＜Surface roughness of anti-reflective film＞ Using a laser microscope (“VK-X200” manufactured by KEYENCE), the arithmetic average roughness Ra was obtained from the observation image (100 μm×100 μm) with a magnification of 10 times.

＜Surface hardness of adhesive＞ Place the adhesive layer of the surface protective film facing up and fix it on the stage of the nano indentation system (“TI950 TriboIndenter” manufactured by Hysitron). Using a Berkovich (triangular pyramid) type diamond indenter (curvature radius of the tip: 0.1 μm), slowly apply a load, and calculate the indentation hardness at a depth of 1500 nm (indentation load/between indenter and sample Projected contact area). Furthermore, the projected contact area between the indenter and the sample is calculated by the method described in Japanese Patent Laid-Open No. 2005-195357.

＜Peeling force of surface protective film＞ Cut the anti-reflective film with protective film into a width of 50 mm×100 mm in length. After standing in a standard environment for 30 minutes, use a double-sided adhesive tape to cut the anti-reflective film on the side of the polyethylene terephthalate film Fixed to acrylic board. Peel off the surface protection film at the end of the sample in the longitudinal direction, and conduct a peel test at a peel angle of 180° and a tensile speed of 0.3 m/min.

＜Adhesion of protective film＞ Paste a glass plate on the side of the polyethylene terephthalate film of the anti-reflective film, and process it in an autoclave at 50°C and 0.5 MPa for 15 minutes. Then, after standing for 30 minutes in a standard environment, visually confirm whether there are bubbles at the interface between the protective film and the anti-reflection film. The case where bubbles are confirmed is set to "bad adhesion (×)", and the case where no bubbles are seen is set to "good adhesion (○)".

<Pollution> Paste a black acrylic sheet on the side of the polyethylene terephthalate film of the anti-reflective film. After standing for 250 hours in a constant temperature and humidity bath with a temperature of 60°C and a relative humidity of 90%, the surface protective film is peeled off. Stick the adhesive tape on the surface of a part of the anti-reflective film and then peel it off to remove the attached material on the surface. Then, in a dark room equipped with a three-wavelength fluorescent lamp, by visually observing the reflected light from the anti-reflective film, it was confirmed whether the area where the adhesive material was removed with the tape was different from other areas. The case where the difference in reflected light is visually observed is set to "contamination (×)", and the case where there is no difference in reflected light is set to "no pollution (○)".

Table 1 shows the composition of the antifouling layer of the antireflection film and the composition of the adhesive layer in the surface protection film in the foregoing Examples and Comparative Examples, and the evaluation results.

[Table 1] Anti-reflective film anti-fouling layer Surface protective film adhesive layer Paste state species Antifouling material Thickness (μm) Dynamic friction coefficient Ra (μm) Water contact angle (°) species Basic polymer composition Crosslinking agent Thickness (μm) Surface hardness (kPa) Peeling force (N/50 mm) Adhesion Polluting initial After damp heat test species Usage (parts by weight) Example 1 A 1 9 0.09 1.34 111.3 111.8 1 2EHA/HEA=96/4 Coronate L 4 twenty one 63 0.04 〇 〇 Example 2 A 1 9 0.09 1.34 111.2 2 2EHA/HEA=96/4 Coronate HX 4 twenty one 142 0.03 〇 〇 Comparative example 1 A 1 9 0.09 1.34 ND 3 2EHA/VAC/AA=54/43/3 Tetrad C 10 twenty three 656 0.07 〇 × Comparative example 2 A 1 9 0.09 1.34 ND 4 Commercial products 15 ND 0.04 × × Comparative example 3 B 2 6 0.17 1.21 117.2 ND 3 2EHA/VAC/AA=54/43/3 Tetrad C 10 twenty three 656 0.20 〇 × Comparative example 4 C 1 4 0.20 1.19 96.2 ND 1 2EHA/HEA=96/4 Coronate L 4 twenty one 63 0.08 〇 〇

In Example 1 and Example 2, no bubbles were seen at the adhesion interface between the anti-fouling layer of the anti-reflective film and the surface protective film, showing good adhesion, and the surface of the anti-fouling layer after the surface protective film was peeled off See pollution. In addition, after the damp heat test with the surface protective film pasted on the anti-reflective film, there was no significant change in the water contact angle of the anti-fouling layer, indicating that no contamination caused by the adhesive of the surface protective film occurred.

In Comparative Example 4 using the same surface protection film as in Example 1, it showed good adhesion and stain resistance as in Example 1, but the water contact angle of the antifouling layer was small and the antifouling property was poor. In Comparative Example 1 and Comparative Example 3 using the surface protective film with the adhesive layer with high surface hardness, the peeling force when peeling off the surface protective film was large, and contamination was observed in the antifouling layer after peeling off the surface protective film. In Comparative Example 2 using a commercially available adhesive-attached film as the surface protective film, the peeling force of the surface protective film is equivalent to that of Example 1, but the thickness of the adhesive layer is small, so the antifouling layer and the surface protective film are in close contact Poor sex. In addition, in Comparative Example 2, contamination was observed in the antifouling layer after peeling off the surface protective film.

Based on the above results, it can be seen that by using a surface protective film with a specific adhesive layer, even an optical film with an antifouling layer with a large water contact angle and high antifouling properties can exhibit sufficient adhesion. , And can prevent pollution caused by adhesives.

1: Film substrate 2: Hard coating 3: Anti-reflective layer 4: Antifouling layer 7: Film substrate 8: Adhesive layer 10: Optical film (anti-reflective film) 30: Primer layer 31, 33: High refractive index layer 32, 34: low refractive index layer 70: Surface protective film

Fig. 1 is a cross-sectional view showing the laminated structure of an anti-reflection film with a protective film.

1: Film substrate

2: Hard coating

3: Anti-reflective layer

4: Antifouling layer

7: Film substrate

8: Adhesive buildup

10: Optical film

30: Primer

31: High refractive index layer

32: Low refractive index layer

33: High refractive index layer

34: Low refractive index layer

70: Surface protective film

100: Anti-reflective layer

Claims (9)

An optical film with a protective film, comprising: an optical film provided with an antifouling layer as the outermost layer on the first main surface of a first film substrate; and a surface protective film temporarily attached to the optical film The above antifouling layer, The surface protection film is provided with an adhesive layer on the second film substrate, The thickness of the adhesive layer is 16 μm or more, The water contact angle of the antifouling layer is above 100°, The antifouling layer is in contact with the adhesive layer, The adhesion between the antifouling layer of the optical film and the adhesive layer of the surface protective film does not reach 0.07 N/50 mm. The optical film with protective film of claim 1, wherein the surface hardness of the adhesive layer is 600 kPa or less. The optical film with protective film of claim 1 or 2, wherein the dynamic friction coefficient of the antifouling layer is 0.15 or less. The optical film with protective film of claim 1 or 2, wherein the antifouling layer contains a fluorine-based resin having a perfluoropolyether skeleton. The optical film with a protective film of claim 1 or 2, wherein the optical film has at least one inorganic film between the first film substrate and the antifouling layer. The optical film with protective film of claim 5, wherein the above-mentioned inorganic film is an anti-reflection layer comprising a plurality of inorganic films with different refractive indexes. The optical film with a protective film of claim 1 or 2, wherein the optical film is provided with a hard coat layer on the first main surface of the first film substrate. The optical film with a protective film of claim 7, wherein the hard coat layer is an anti-glare hard coat layer containing fine particles. The optical film with protective film of claim 1 or 2, wherein the arithmetic average roughness of the surface of the antifouling layer is 0.1-2.5 μm.

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