Optical Film with Antifouling Layer and Method for Manufacturing the Same

Abstract

An optical film with an antifouling layer suitable for achieving a good transparent appearance of the antifouling layer and a manufacturing method thereof. The manufacturing method includes the steps of forming an antifouling layer (15) on one side of a transparent substrate film (11); laminating the adhesive surface (16a) of a release film (16) to the antifouling layer (15); peeling the release film (16) from the antifouling layer (15); laminating the adhesive surface (17a) of a protective film (17) to the antifouling layer (15). The adhesive force of the release film (16) to the antifouling layer (15) is 0.008 N / 50 mm or more. The film (Z) sequentially includes a transparent substrate film (11), an antifouling layer (15), and a protective film (17). The protective film (17) is laminated to the antifouling layer (15) using the adhesive surface (17a). The ratio of the thickness of the antifouling layer after removing the protective film to the thickness of the antifouling layer in the state with the protective film is 0.9 or more and 1.0 or less.

Description

Technical Field

[0001] The present invention relates to an optical film with an antifouling layer and a method for manufacturing the same. Background Art

[0002] From the viewpoint of antifouling properties, an optical film with an antifouling layer, for example, is attached to the outer surface on the image display side of a display such as a touch panel display. The optical film with an antifouling layer includes: a transparent substrate film, and an antifouling layer disposed on the outermost surface on one side of the transparent substrate film. The antifouling layer suppresses the adhesion of contaminants such as hand oils to the outer surface of the display, and in addition, the adhered contaminants are easily removed. Technologies related to such an optical film with an antifouling layer are described, for example, in Patent Document 1 below.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-227898 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the manufacturing process of an optical film with an antifouling layer, the antifouling layer is formed of a highly water-repellent material by, for example, a wet coating method or a dry coating method. However, the present inventors have obtained the following insight: on the exposed surface of the antifouling layer, since the highly water-repellent material is not sufficiently fixed to the antifouling layer structure, a cloudy portion (a portion where the material is not fixed) sometimes occurs. This defect is particularly likely to occur in the case where the antifouling layer is formed by a dry coating method. On the other hand, from the viewpoints of film strength and antifouling function, the antifouling layer needs to be formed to a sufficient thickness. However, there is a tendency that the thicker the formed antifouling layer is, the thicker the above-described unfixed portion of the material is formed. From the viewpoint of transparent appearance, the formation of cloudiness on the surface of the antifouling layer is not preferable.

[0008] The present invention provides a method for manufacturing an optical film with an antifouling layer and an optical film with an antifouling layer suitable for achieving good transparent appearance of the antifouling layer.

[0009] Means for Solving the Problems

[0010] The present invention [1] includes a method for manufacturing an optical film with an antifouling layer, which is a method for manufacturing an optical film with an antifouling layer by a roll-to-roll method. The manufacturing method includes: an antifouling layer forming step of forming an antifouling layer on one side in the thickness direction of a transparent substrate film; a first bonding step of bonding the bonding surface of a release film having a bonding surface to the antifouling layer; a peeling step of peeling the release film from the antifouling layer; and a second bonding step of bonding the bonding surface of a protective film having a bonding surface to the antifouling layer. The adhesive force of the release film to the antifouling layer is 0.008 N / 50 mm or more.

[0011] In the first bonding step of the method for manufacturing an optical film with an antifouling layer of the present invention, an antifouling layer material (unfixed material) that is not sufficiently fixed to the antifouling layer structure adheres to the bonding surface of the release film. In the subsequent peeling step, the release film having an adhesive force of 0.008 N / 50 mm or more to the antifouling layer is peeled from the antifouling layer. When the release film is peeled, at least a part of the unfixed material is removed from the antifouling layer along with the release film. Implementing the above first bonding step and peeling step after the antifouling layer forming step is suitable for removing the unfixed material from the surface of the antifouling layer. Moreover, in the second bonding step, the antifouling layer that has undergone the removal of the unfixed material is covered and protected by the protective film. Therefore, this manufacturing method is suitable for suppressing cloudiness caused by the unfixed material in the antifouling layer and achieving good transparent appearance.

[0012] The present invention [2] includes the method for manufacturing an optical film with an antifouling layer described in [1] above, wherein, in the antifouling layer forming step, the antifouling layer is formed by a dry coating method.

[0013] Such a configuration is preferable for ensuring a high bonding force of the antifouling layer to the substrate on which the antifouling layer is laminated, and thus is preferable for ensuring the peel resistance of the antifouling layer. A high peel resistance of the antifouling layer contributes to the maintenance of the antifouling function of the antifouling layer. This manufacturing method is suitable for achieving good transparent appearance of the antifouling layer even when the antifouling layer is formed by a dry coating method.

[0014] The present invention [3] includes an optical film with an antifouling layer, which sequentially includes: a transparent substrate film, an antifouling layer, and a protective film. The protective film has a bonding surface on the antifouling layer side and is bonded to the antifouling layer with this bonding surface. The ratio of the thickness of the antifouling layer after removing the protective film to the thickness of the antifouling layer in the state where the protective film is provided is 0.9 or more and 1.0 or less.

[0015] Such an optical film with an antifouling layer is suitable for removing unfixed materials from the surface of the antifouling layer by peeling off the protective film from the antifouling layer when the unfixed materials remain on the surface of the antifouling layer. Therefore, the optical film with an antifouling layer of the present invention is suitable for suppressing cloudiness caused by unfixed materials by the antifouling layer, thereby achieving good transparent appearance.

[0016] The present invention [4] includes the optical film with an antifouling layer described in [3] above, wherein the antifouling layer is a dry-coated film.

[0017] Such a configuration is preferable for ensuring a high bonding strength of the antifouling layer to the substrate on which the antifouling layer is laminated, and thus is preferable for ensuring the peel resistance of the antifouling layer. A high peel resistance of the antifouling layer contributes to the maintenance of the antifouling function of the antifouling layer.

[0018] The present invention [5] includes the optical film with an antifouling layer described in [3] or [4] above, wherein the F intensity ratio of the antifouling layer after removing the protective film is 0.18 or more.

[0019] Such a configuration is preferable for the antifouling layer to ensure the antifouling function and antifouling durability.

[0020] The present invention [6] includes the optical film with an antifouling layer described in any one of [3] to [5] above, wherein the F intensity ratio of the antifouling layer after removing the protective film is 0.98 or less.

[0021] Such a configuration is preferable from the viewpoint of thinning the optical film with an antifouling layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A to Figure 1 D of the drawings show a part of the steps of a manufacturing method of the optical film with an antifouling layer of the present invention. Figure 1 A of the drawings shows the step of preparing a transparent base film, Figure 1 B of the drawings shows the step of forming a hard coat, Figure 1 C of the drawings shows the step of forming an adhesion layer, Figure 1 D of the drawings shows the step of forming an antireflection layer.

[0023] Figure 2 A to Figure 2 C of the drawings show the steps following the step shown in Figure 1 D of the drawings. Figure 2 A of the drawings shows the step of forming an antifouling layer, Figure 2 B of the drawings shows the step of laminating a peeling film on the antifouling layer, Figure 2 C of the drawings shows the step of peeling the peeling film from the antifouling layer.

[0024] Figure 3 ForFigure 2 The process following the process shown in C shows the process of laminating a protective film.

[0025] Figure 4 A modified example of the optical film with an anti-fouling layer of the present invention is shown. In this modified example, an anti-reflection layer is not provided.

[0026] Explanation of reference numerals

[0027] Z Optical film (optical film with anti-fouling layer)

[0028] D Thickness direction

[0029] 11 Transparent base film

[0030] 12 Hard coat

[0031] 13 Adhesive layer

[0032] 14 Anti-reflection layer

[0033] 14a First high refractive index layer

[0034] 14b First low refractive index layer

[0035] 14c Second high refractive index layer

[0036] 14d Second low refractive index layer

[0037] 15 Anti-fouling layer

[0038] 15a Surface

[0039] 16 Release film

[0040] 16a Adhesive surface

[0041] 17 Protective film

[0042] 17a Adhesive surface

[0043] 18 Inorganic oxide base layer Detailed description of the invention

[0044] Figure 1 of A to Figure 3 is a process chart of an embodiment of a method for manufacturing an optical film with an anti-fouling layer of the present invention. The method for manufacturing an optical film with an anti-fouling layer is implemented by a roll-to-roll method. In this embodiment, it includes: a preparation process ( Figure 1 of A), a hard coat formation process ( Figure 1 of B), an adhesive layer formation process ( Figure 1 of C), an anti-reflection layer formation process ( Figure 1 of D), an anti-fouling layer formation process ( Figure 2 of A), a first lamination process (Figure 2 B) of peeling process, Figure 2 C) of, and the second lamination process Figure 3 ). In this embodiment, the manufacturing Figure 3 The optical film Z shown. Specifically as follows.

[0045] First, in the preparation process, as Figure 1 shown in A of, prepare the transparent base film 11. The transparent base film 11 has a long strip shape in this embodiment so that this manufacturing method can be implemented by a roll-to-roll method.

[0046] The transparent base film 11 is a flexible transparent resin film. As the material of the transparent base film 11, for example, polyester resin, polyolefin resin, polystyrene resin, acrylic resin, polycarbonate resin, polyethersulfone resin, polysulfone resin, polyamide resin, polyimide resin, cellulose resin, norbornene resin, polyarylate resin, and polyvinyl alcohol resin can be cited. As the polyester resin, for example, polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate can be cited. As the polyolefin resin, for example, polyethylene, polypropylene, and cycloolefin polymer (COP) can be cited. As the cellulose resin, for example, cellulose triacetate (TAC) can be cited. These materials can be used alone or in combination of two or more. As the material of the transparent base film 11, from the viewpoints of transparency and strength, one selected from the group consisting of polyester resin, polyolefin resin, and cellulose resin is used, and more preferably one selected from the group consisting of PET, COP, and TAC is used.

[0047] The surface 11a (the surface for laminating the hard coat 12 described later) on one surface in the thickness direction D of the transparent base film 11 can be subjected to surface modification treatment. As the surface modification treatment, for example, corona treatment, plasma treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment can be cited.

[0048] The thickness of the transparent base film 11 is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more from the viewpoint of strength. The thickness of the transparent base film 11 is preferably 300 μm or less, more preferably 200 μm or less from the viewpoint of processability.

[0049] The total light transmittance (JIS K 7375-2008) of the transparent base film 11 is preferably 80% or more, more preferably 90% or more, and further preferably 95% or more. Such a configuration is suitable for ensuring the transparency required for the optical film Z when the optical film Z is provided on the surface of a display such as a touch panel display. The total light transmittance of the transparent base film 11 is, for example, 100% or less.

[0050] Next, in the hard coat forming step, as shown in B of Figure 1 , a hard coat 12 is formed on the surface 11a (one surface in the thickness direction D) of the transparent substrate film 11. The hard coat 12 is a layer for making the exposed surface ( Figure 2 the upper surface in the figure of the optical film Z shown in C of

[0051] of the optical film Z during use) less likely to form scratches. The hard coat forming step is carried out by a roll-to-roll method.

[0052] As the curable resin, for example, polyester resin, acrylic urethane resin, acrylic resin (excluding acrylic urethane resin), urethane resin (excluding acrylic urethane resin), amide resin, silicone resin, epoxy resin, and melamine resin can be cited. These curable resins can be used alone or in combination of two or more. From the viewpoint of ensuring the high hardness of the hard coat 12, acrylic urethane resin is preferably used as the curable resin.

[0053] In addition, as the curable resin, for example, ultraviolet curable resin and thermosetting resin can be cited. When the curable resin composition contains an ultraviolet curable resin, the above-mentioned coating film is cured by ultraviolet irradiation. When the curable resin composition contains a thermosetting resin, the above-mentioned coating film is cured by heating. From the viewpoint of contributing to the improvement of the manufacturing efficiency of the optical film Z by enabling curing without high-temperature heating, ultraviolet curable resin is preferably used as the curable resin. The ultraviolet curable resin contains at least one selected from the group consisting of ultraviolet curable monomers, ultraviolet curable oligomers, and ultraviolet curable polymers. As a specific example of the composition containing an ultraviolet curable resin, the hard coat forming composition described in Japanese Patent Application Laid-Open No. 2016-179686 can be cited.

[0054] As the solvent contained in the curable resin composition, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, toluene, xylene, methanol, ethanol, isopropyl alcohol, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, dichloromethane, and chloroform can be cited.

[0055] The curable resin composition may contain fine particles. Blending fine particles into the curable resin composition helps to adjust the hardness of the hard coat 12, adjust the surface roughness, adjust the refractive index, and impart antiglare properties. Examples of the fine particles include metal oxide particles, glass particles, and organic particles. Examples of the material for the metal oxide particles include silica, alumina, titanium dioxide, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of the material for the organic particles include polymethyl methacrylate, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate.

[0056] Regarding the thickness of the hard coat 12, from the viewpoint of ensuring the hardness of the hard coat 12 and thus ensuring the hardness of the surface of the antifouling layer 15, it is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more. Regarding the thickness of the hard coat 12, from the viewpoint of ensuring the flexibility of the optical film Z, it is preferably 50 μm or less, more preferably 40 μm or less, further preferably 35 μm or less, and particularly preferably 30 μm or less.

[0057] The surface 12a (the surface on which the adhesion layer 13 described later is laminated) on one surface in the thickness direction D of the hard coat 12 is surface-modified as needed. Examples of the surface modification treatment include plasma treatment, corona treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment. From the viewpoint of ensuring a high adhesion between the hard coat 12 and the adhesion layer 13, the surface 12a is preferably subjected to plasma treatment. When the surface 12a is subjected to plasma treatment, for example, argon is used as the inert gas. In addition, the discharge power in the plasma treatment is, for example, 10 W or more and, for example, 10000 W or less.

[0058] Next, in the adhesion layer formation step, as Figure 1As shown in C of FIG. 0, an adhesion layer 13 is formed on the surface 12a (one surface in the thickness direction D) of the hard coat layer 12. The adhesion layer 13 is a layer for ensuring the adhesion of an inorganic oxide layer (an antireflection layer 14 described later in this embodiment) to an organic layer (the hard coat layer 12 in this embodiment). As materials for such an adhesion layer 13, for example, metals such as silicon, nickel, chromium, aluminum, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, palladium, alloys of two or more of these metals, and oxides of these metals can be cited. From the viewpoint of achieving both adhesion to both the organic layer (the hard coat layer 12 in this embodiment) and the inorganic oxide layer (the antireflection layer 14 in this embodiment) and transparency of the adhesion layer 13, indium tin oxide (ITO) or silicon oxide (SiOx) is preferably used as the material for the adhesion layer 13. When using silicon oxide as the material for the adhesion layer 13, SiOx with an oxygen content less than the stoichiometric composition is preferably used, and SiOx with x of 1.2 or more and 1.9 or less is more preferably used.

[0059] The adhesion layer 13 is formed, for example, by forming a film of the material using a dry coating method. As the dry coating method, sputtering, vacuum evaporation, and CVD can be cited, and sputtering is preferably used.

[0060] In the sputtering method, while introducing a gas into the sputtering chamber under vacuum conditions, a negative voltage is applied to a target disposed on a cathode. Thereby, glow discharge occurs to ionize gas atoms, and the gas ions impact the target surface at high speed, ejecting the target material from the target surface, and depositing the ejected target material on a specified surface. From the viewpoint of film formation speed, reactive sputtering is preferably used as the sputtering method. In reactive sputtering, a metal target is used as the target, and a mixed gas of an inert gas such as argon and oxygen (reactive gas) is used as the above-mentioned gas. By adjusting the flow rate ratio (sccm) of the inert gas to oxygen, the proportion of oxygen contained in the formed inorganic oxide can be adjusted.

[0061] As a power source for implementing the sputtering method, for example, a DC power source, an AC power source, an RF power source, and an MFAC power source (an AC power source with a frequency band of several kHz to several MHz) can be cited. The discharge voltage in the sputtering method is, for example, 200 V or more, and is, for example, 1000 V or less. In addition, the film formation pressure in the sputtering chamber for implementing the sputtering method is preferably 0.01 Pa or more, more preferably 0.05 Pa or more, and further preferably 0.1 Pa or more. In addition, the film formation pressure is, for example, 2 Pa or less from the viewpoint of discharge stability.

[0062] Regarding the thickness of the adhesion layer 13, from the viewpoint of achieving both ensuring the adhesion between the hard coat layer 12 and the antireflection layer 14 and transparency of the adhesion layer 13, it is preferably 1 nm or more and 10 nm or less.

[0063] Next, in the antireflection layer formation step, as shown in D of Figure 1 , an antireflection layer 14 is formed on one surface in the thickness direction D of the adhesion layer 13. The antireflection layer 14 is a layer for suppressing the reflection intensity of external light. Figure 1 The antireflection layer 14 alternately has a high refractive index layer with a relatively large refractive index and a low refractive index layer with a relatively small refractive index in the thickness direction. In the antireflection layer 14, due to the interference effect between the reflected lights at the multiple interfaces of the multiple thin layers (high refractive index layer, low refractive index layer) contained in the same layer, the intensity of the reflected light is attenuated. In addition, in the antireflection layer 14, by adjusting the optical film thickness (the product of the refractive index and the thickness) of each thin layer, the interference effect that attenuates the intensity of the reflected light can be exhibited. Such an antireflection layer 14 specifically has a first high refractive index layer 14a, a first low refractive index layer 14b, a second high refractive index layer 14c, and a second low refractive index layer 14d in this order toward one side in the thickness direction D in the present embodiment.

[0064] The first high refractive index layer 14a, the first low refractive index layer 14b, the second high refractive index layer 14c, and the second low refractive index layer 14d can each be formed by forming a film of a material using a dry coating method. As the dry coating method, sputtering, vacuum evaporation, and CVD can be cited, and sputtering is preferably used. As the sputtering method, from the viewpoint of the film formation speed, reactive sputtering is preferred. The conditions of the sputtering method in this step are the same as those of the sputtering method in the adhesion layer formation step described above.

[0065] The first high refractive index layer 14a and the second high refractive index layer 14c are each formed of a high refractive index material having a refractive index of preferably 1.9 or more at a wavelength of 550 nm. From the viewpoint of balancing high refractive index and low absorption of visible light, as the high refractive index material, for example, niobium oxide (Nb2O5), titanium oxide, zirconium oxide, indium tin oxide (ITO), and antimony tin oxide (ATO) can be cited, and niobium oxide is preferably used.

[0066] The optical film thickness (the product of the refractive index and the thickness) of the first high refractive index layer 14a is, for example, 20 nm or more and, for example, 55 nm or less. The optical film thickness of the second high refractive index layer 14c is, for example, 60 nm or more and, for example, 330 nm or less.

[0067] The first low refractive index layer 14b and the second low refractive index layer 14d are each formed of a low refractive index material having a refractive index of preferably 1.6 or less at a wavelength of 550 nm. From the viewpoint of balancing low refractive index and low absorption of visible light, as the low refractive index material, for example, silicon dioxide (SiO2) and magnesium fluoride can be cited, and silicon dioxide is preferably used.

[0068]

[0069] ​The optical film thickness of the first low refractive index layer 14b is, for example, 15 nm or more and, for example, 70 nm or less. The optical film thickness of the second low refractive index layer 14d is, for example, 100 nm or more and, for example, 160 nm or less.

[0070] If necessary, the exposed surface of the antireflection layer 14 is surface-modified. When plasma treatment is performed as the surface modification treatment, examples of the treatment gas include oxygen and argon. In addition, the discharge power in the plasma treatment is, for example, 10 W or more, preferably 50 W or more. This discharge power is, for example, 10,000 W or less, preferably 8,000 W or less, more preferably 5,000 W or less, further preferably 4,000 W or less, and particularly preferably 3,000 W or less.

[0071] Next, in the antifouling layer forming step, as Figure 2 shown in A of, an antifouling layer 15 is formed on one surface in the thickness direction D of the antireflection layer 14. The antifouling layer 15 is a layer having an antifouling function. The antifouling function of the antifouling layer 15 includes a function of suppressing the adhesion of contaminants such as hand oils to the exposed surface of the film when using the optical thin film Z, and a function of easily removing the adhered contaminants.

[0072] The antifouling layer 15 is formed by depositing an antifouling layer material on the antireflection layer 14 using a dry coating method. That is, the antifouling layer 15 is a film formed by a dry coating method (dry coating film). Examples of the dry coating method include a vacuum evaporation method, a sputtering method, and CVD. The antifouling layer 15 is preferably a film formed by a vacuum evaporation method (vacuum evaporation film). The configuration of the antifouling layer 15 being a dry coating film (preferably a vacuum evaporation film) is suitable for ensuring a high bonding force of the antifouling layer 15 to the substrate, and thus is suitable for ensuring the peel resistance of the antifouling layer 15. A high peel resistance of the antifouling layer 15 contributes to the maintenance of the antifouling function of the antifouling layer 15.

[0073] As the material of the antifouling layer 15, an organic fluorine compound having a fluorinated alkyl group at the end is preferably used. Due to the superposition of high hydrophobicity and high lipophobicity caused by the terminal fluorinated alkyl group, this organic fluorine compound is suitable for making the antifouling layer 15 exhibit excellent antifouling properties. As such an organic fluorine compound, an alkoxysilane compound having a perfluoropolyether group represented by the following general formula (1) is preferably used.

[0074] R 1 -R 2 -X-(CH2) m -Si(OR 3 )3(1)

[0075] In the general formula (1), R 1A linear or branched fluorinated alkyl group in which one or more hydrogen atoms in the alkyl group are substituted with fluorine atoms (the number of carbon atoms is, for example, 1 or more and 20 or less), preferably a perfluoroalkyl group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms.

[0076] R 2 A structure representing a repeating structure containing at least one perfluoropolyether (PFPE) group, preferably a structure representing a repeating structure containing two PFPE groups. As the repeating structure of the PFPE group, for example, a repeating structure of a linear PFPE group and a repeating structure of a branched PFPE group can be cited. As the repeating structure of the linear PFPE group, for example, -(OC n F 2n ) p - represented structure (n represents an integer of 1 or more and 20 or less, p represents an integer of 1 or more and 50 or less. The same applies hereinafter). As the repeating structure of the branched PFPE group, for example, -(OC(CF3)2) p - represented structure, and -(OCF2CF(CF3)CF2) p - represented structure. As the repeating structure of the PFPE group, preferably a repeating structure of a linear PFPE group can be cited, and more preferably -(OCF2) p - and -(OC2F4) p -.

[0077] R 3 Represents an alkyl group having 1 to 4 carbon atoms, preferably a methyl group.

[0078] X represents an ether group, a carbonyl group, an amino group, or an amide group, preferably an ether group.

[0079] m represents an integer of 1 or more. In addition, m represents an integer preferably of 20 or less, more preferably of 10 or less, and further preferably of 5 or less.

[0080] Among such alkoxysilane compounds having a perfluoropolyether group, a compound represented by the following general formula (2) is preferably used.

[0081] CF3-(OCF2) q -(OC2F4) r -O-(CH2)3-Si(OCH3)3 (2)

[0082] In the general formula (2), q represents an integer of 1 or more and 50 or less, and r represents an integer of 1 or more and 50 or less.

[0083] In addition, the alkoxysilane compound having a perfluoropolyether group can be used alone or in combination of two or more.

[0084] In this step, an antifouling layer 15 with a thickness T0 greater than the thickness T1 (the thickness of the antifouling layer 15 after the peeling step) and the thickness T2 (the thickness of the antifouling layer 15 after the protective film is removed, the final target thickness) described later is formed. The thickness T0 is in a range greater than the thicknesses T1 and T2. For example, it is 6 nm or more, preferably 8 nm or more, more preferably 10 nm or more, further preferably 12 nm or more, and particularly preferably 15 nm or more. The difference (T0 - T1) between the thickness T1 and the thickness T0 is preferably 0.1 nm or more, more preferably 0.2 nm or more, further preferably 0.3 nm or more, and preferably 8 nm or less, more preferably 7 nm or less, further preferably 6 nm or less. The ratio (T1 / T0) of the thickness T1 to the thickness T0 is preferably 0.7 or more, more preferably 0.8 or more, further preferably 0.85 or more, and preferably 0.99 or less, more preferably 0.94 or less, further preferably 0.90 or less. These configurations related to the thickness T0 are preferable for the antifouling layer 15 after the protective film is removed to obtain a substantial thickness T2.

[0085] When using the F intensity ratio as an index for the thickness of the antifouling layer 15, the F intensity ratio (F intensity ratio R0) of the antifouling layer 15 formed in this step is, for example, 0.20 or more, preferably 0.26 or more, more preferably 0.33 or more, further preferably 0.39 or more, and particularly preferably 0.49 or more. The ratio (R1 / R0) of the F intensity ratio (F intensity ratio R1) of the antifouling layer 15 after the peeling step described later to the F intensity ratio R0 is preferably 0.7 or more, more preferably 0.8 or more, further preferably 0.85 or more, and preferably 0.99 or less, more preferably 0.94 or less, further preferably 0.90 or less (this ratio (R1 / R0) of the F intensity ratio reflects the above-mentioned thickness ratio (T1 / T0) of the antifouling layer 15. That is, the ratio (R1 / R0) of the F intensity ratio is the same as the thickness ratio (T1 / T0)). These configurations related to the F intensity ratio R0 are preferable for the antifouling layer 15 after the protective film is removed to obtain a substantial thickness T2. The F intensity ratio refers to the ratio of the X-ray intensity (F intensity) of fluorine (F) obtained by fluorescence X-ray analysis of the measurement target film under specified conditions to the X-ray intensity of fluorine (F) obtained by fluorescence X-ray analysis of a glass as a standard sample containing 4.96 mass% fluorine atoms under the same conditions. The glass used as the standard sample is "XRF-PF3" manufactured by LGC Standards. The measurement method of the F intensity ratio is specifically described in the examples below.

[0086] In addition, in this process, unfixed portions (not shown) where the antifouling layer material is not sufficiently fixed to the antifouling layer structure are generated on the surface 15a of the antifouling layer 15. On the surface 15a, the unfixed portions become cloudy, which causes color unevenness.

[0087] Preferably, a series of processes from the above-mentioned adhesion layer formation process to the antifouling layer formation process are carried out in a continuous production line while moving the workpiece film by a roll-to-roll method. In the processes in a continuous production line, the workpiece film is not exposed to the atmosphere even once, and it is preferably not wound into a roll.

[0088] Next, in the first bonding process, as Figure 2 shown in B of, the release film 16 is bonded to the antifouling layer 15. The release film 16 has an adhesive surface 16a on one side of the film. In this process, specifically, using a roll-to-roll type bonding device, the adhesive surface 16a of the release film 16 is bonded to the surface 15a of the antifouling layer 15. In this process, by bonding the side of the adhesive surface 16a of the release film 16 to the surface 15a of the antifouling layer 15, the above-mentioned unfixed portions (antifouling layer material) in the antifouling layer 15 adhere to the adhesive surface 16a.

[0089] The release film 16 includes a film base material and an adhesive layer on the film base material. The surface of the adhesive layer on the side opposite to the film base material forms the adhesive surface 16a. As the film base material, for example, the resin film described above for the transparent base film 11 can be cited. The thickness of the film base material is preferably 5 μm or more, more preferably 10 μm or more, and preferably 300 μm or less, more preferably 200 μm or less. As the material of the adhesive layer, for example, acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, polyurethane adhesives, polyamide adhesives, epoxy adhesives, and vinyl alkyl ether adhesives can be cited. The thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, and preferably 50 μm or less, more preferably 30 μm or less.

[0090] In the bonding device, the bonding temperature is preferably 10°C or more, more preferably 20°C or more, and preferably 100°C or less, more preferably 50°C or less. In addition, the bonding pressure in this process is preferably 0.05 MPa or more, more preferably 0.1 MPa or more, and preferably 1 MPa or less, more preferably 0.8 MPa or less.

[0091] In this step, the adhesive force of the release film 16 attached to the antifouling layer 15 to the antifouling layer 15 is 0.008 N / 50 mm or more, preferably 0.015 N / 50 mm or more, and more preferably 0.02 N / 50 mm or more. Such a configuration is suitable for ensuring good adhesion of the unfixed portion described above to the release film 16 and being able to be removed from the antifouling layer 15 in the subsequent release step. In addition, from the viewpoint of the peelability of the release film 16, the adhesive force is preferably 0.1 N / 50 mm or less, more preferably 0.09 N / 50 mm or less, and further preferably 0.08 N / 50 mm or less. The adhesive force is measured by the method described later in the examples.

[0092] Next, in the release step, as shown in C of Figure 2 , the release film 16 is peeled from the antifouling layer 15. The peeling speed is, for example, 5 to 20 m / min. This step is carried out by a roll-to-roll method. In this step, at least a part of the unfixed portion (antifouling layer material) attached to the adhesive surface 16a of the release film 16 is removed from the antifouling layer 15 together with the release film 16. As a result, at least a part of the unfixed portion is removed from the antifouling layer 15. The above-described first bonding step and release step are carried out as a series of steps functionally. That is, the first bonding step and release step constitute a step (transfer step) of transferring the unfixed portion on the surface 15a of the antifouling layer 15 to the release film 16.

[0093] By removing the unfixed portion (antifouling layer material) in the release step, the antifouling layer 15 becomes thinner. For the thickness T1 of the antifouling layer 15 after this step, from the viewpoint of balancing the antifouling function and antifouling durability of the antifouling layer 15, it is preferably 4 nm or more, more preferably 6 nm or more, further preferably 8 nm or more, and particularly preferably 10 nm or more. In addition, from the viewpoint of thinning the optical film Z, the thickness T1 is preferably 30 nm or less, more preferably 25 nm or less, and further preferably 20 nm or less.

[0094] When using the F strength ratio as an index of the thickness of the antifouling layer 15, for the F strength ratio (F strength ratio R1) of the antifouling layer 15 after the release step, from the viewpoint of balancing the antifouling function and antifouling durability of the antifouling layer 15, it is preferably 0.080 or more, more preferably 0.125 or more, further preferably 0.170 or more, and further more preferably 0.180 or more. In addition, for the F strength ratio R1, from the viewpoint of thinning the optical film Z, it is preferably 1.00 or less, more preferably 0.800 or less, and further preferably 0.600 or less.

[0095] Next, in the second bonding step, as shown in Figure 3As shown, an antifouling layer 15 is bonded to a protective film 17. The protective film 17 has an adhesive surface 17a on one side of the film. In this process, specifically, the adhesive surface 17a of the protective film 17 is bonded to the surface 15a of the antifouling layer 15 by a roll-to-roll type bonding device. When an unfixed material remains on the surface of the antifouling layer 15 after the above-described first bonding process and peeling process, in this process, by bringing the adhesive surface 17a side of the protective film 17 into contact with the surface 15a of the antifouling layer 15, the unfixed remaining portion (antifouling layer material) in the antifouling layer 15 adheres to the adhesive surface 17a.

[0096] The protective film 17 includes a film substrate and an adhesive layer on the film substrate. The surface of the adhesive layer opposite to the film substrate forms the adhesive surface 17a. As the film substrate, for example, the resin film described above regarding the transparent substrate film 11 can be cited. The thickness of the film substrate is preferably 5 μm or more, more preferably 10 μm or more, and preferably 300 μm or less, more preferably 200 μm or less. As the material of the adhesive layer, for example, acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, polyurethane adhesives, polyamide adhesives, epoxy adhesives, and vinyl alkyl ether adhesives can be cited. The thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, and preferably 50 μm or less, more preferably 30 μm or less.

[0097] In the bonding device, the bonding temperature is preferably 10°C or more, more preferably 20°C or more, and preferably 100°C or less, more preferably 50°C or less. In addition, the bonding pressure in this process is preferably 0.05 MPa or more, more preferably 0.1 MPa or more, and preferably 1 MPa or less, more preferably 0.8 MPa or less.

[0098] The adhesive force of the protective film 17 bonded to the antifouling layer 15 in this process to the antifouling layer 15 is preferably 0.008 N / 50 mm or more, more preferably 0.015 N / 50 mm or more, and further preferably 0.02 N / 50 mm or more. Such a configuration is suitable for ensuring good adhesion of the unfixed remaining portion to the protective film 17 to an extent that the unfixed remaining portion adheres to the protective film 17 and can be removed from the antifouling layer 15 when the protective film 17 is peeled off. In addition, from the viewpoint of the peelability of the protective film 17, the adhesive force is preferably 0.1 N / 50 mm or less, more preferably 0.09 N / 50 mm or less, and further preferably 0.08 N / 50 mm or less. This adhesive force is measured by the method described later in the examples.

[0099] As described above, an optical film Z is manufactured. On one side of the optical film Z facing the thickness direction D, there are provided in sequence: a transparent base film 11, a hard coat 12, an adhesion layer 13, an antireflection layer 14, an antifouling layer 15, and a protective film 17. The optical film Z has a shape extending in a direction (plane direction) orthogonal to the thickness direction D. Further, for the optical film Z, the transparent base film 11 side is adhered to an adherend by, for example, an adhesive and used. As the adherend, for example, a transparent cover disposed on the image display side in a display such as a touch panel display can be cited. In the optical film Z, the antifouling layer 15 can be protected by the protective film 17. Therefore, the optical film Z is suitable for maintaining the antifouling function of the antifouling layer 15 and the like, and the durability as an optical film with an antifouling layer until the protective film 17 is peeled off and the optical film with an antifouling layer is used.

[0100] In the optical film Z, the ratio (T2 / T1) of the thickness T2 of the antifouling layer 15 after removing (peeling off) the protective film 17 to the thickness T1 of the antifouling layer 15 in the state where the protective film 17 is provided is preferably 0.9 or more, more preferably 0.92 or more, and further preferably 1.0 or less or 0.99 or less. When using the F intensity ratio as an index of the thickness of the antifouling layer 15, the ratio (R2 / R1) of the F intensity ratio (F intensity ratio R2) of the antifouling layer 15 after removing the protective film 17 to the above-mentioned F intensity ratio R1 after the peeling process is preferably 0.9 or more, more preferably 0.92 or more, and further preferably 1.0 or less or 0.99 or less (this ratio (R2 / R1) of the F intensity ratio reflects the thickness ratio (T2 / T1) of the antifouling layer 15. That is, the ratio (R2 / R1) of the F intensity ratio is the same as the thickness ratio (T2 / T1)). These configurations are suitable for removing the unfixed material from the surface 15a of the antifouling layer 15 by peeling the protective film 17 from the antifouling layer 15 when the unfixed material remains on the surface 15a of the antifouling layer 15. Therefore, this configuration is suitable for suppressing cloudiness caused by the unfixed material in the antifouling layer 15 and achieving good transparent appearance.

[0101] Regarding the thickness T2 of the antifouling layer 15 after removing the protective film 17, from the viewpoint of balancing the antifouling function and antifouling durability of the antifouling layer 15, it is preferably 6 nm or more, more preferably 8 nm or more, and further preferably 10 nm or more. Further, regarding the thickness T2, from the viewpoint of thinning the optical film Z, it is preferably 30 nm or less, more preferably 25 nm or less, further preferably 20 nm or less, and further more preferably 15 nm or less.

[0102] When using the F intensity ratio as an index for the thickness of the antifouling layer 15, for the F intensity ratio R2 of the antifouling layer 15 after removing the protective film 17, from the viewpoint of balancing the antifouling function and antifouling durability of the antifouling layer 15, it is preferably 0.18 or more, more preferably 0.20 or more, further preferably 0.30 or more, further more preferably 0.35 or more, still further preferably 0.40 or more, and particularly preferably 0.42 or more. In addition, for the F intensity ratio R2, from the viewpoint of thinning the optical film Z, it is preferably 0.98 or less, more preferably 0.80 or less, further preferably 0.66 or less, further more preferably 0.50 or less.

[0103] The water contact angle (pure water contact angle) after peeling the protective film 17 from the surface 15a of the antifouling layer 15 is preferably 110° or more, more preferably 111° or more, further preferably 112° or more, further more preferably 113° or more, and particularly preferably 114° or more. A structure with a water contact angle of the surface 15a as high as this is suitable for achieving high antifouling property of the antifouling layer 15. This water contact angle is, for example, 130° or less. The water contact angle is obtained by forming a water droplet (a droplet of pure water) with a diameter of 2 mm or less on the surface 15a (exposed surface) of the antifouling layer 15 and measuring the contact angle of the water droplet with the surface 15a. The water contact angle of the surface 15a can be adjusted, for example, by adjusting the composition of the antifouling layer 15, the roughness of the surface 15a, the composition of the hard coat 12, and the roughness of the surface of the hard coat 12 on the antifouling layer 15 side.

[0104] In the first bonding step ( Figure 2 B) of this manufacturing method, as described above, the antifouling layer material (unfixed material) that is not sufficiently fixed to the structure of the antifouling layer 15 adheres to the bonding surface 16a of the release film 16. In the peeling step ( Figure 2 C), the release film 16 with an adhesive force of 0.008 N / 50 mm or more to the antifouling layer 15 is peeled from the antifouling layer 15. As a result, at least a part of the unfixed portion in the antifouling layer material is removed from the antifouling layer 15. That is, when this manufacturing method includes the first bonding step and the peeling step after the antifouling layer forming step ( Figure 2 A), it is suitable for removing the aforementioned unfixed material from the antifouling layer 15. Moreover, in the second bonding step ( Figure 3 ), the antifouling layer 15 that has undergone the removal of the unfixed material is covered and protected by the protective film 17. Such a manufacturing method is suitable for suppressing cloudiness caused by the unfixed material in the antifouling layer 15 and achieving good transparent appearance.

[0105] The optical film Z can be an optical film that does not have an antireflection layer 14. To manufacture such an optical film Z, in Figure 1In the process shown in D, it is preferable to form an inorganic oxide base layer 18 for ensuring the peel resistance of the antifouling layer 15 instead of the antireflection layer 14. The antifouling layer forming process will be carried out after such a process ( Figure 2 A), the first bonding process ( Figure 2 B), the peeling process ( Figure 2 C) and the second bonding process ( Figure 3 ) to obtain the optical film Z is shown in Figure 4 .

[0106] The inorganic oxide base layer 18 is formed by film-forming a material using a dry coating method. As the dry coating method, sputtering, vacuum evaporation, and CVD can be mentioned, and sputtering is preferably used. As the material of the inorganic oxide base layer 18, for example, silicon dioxide (SiO2) and magnesium fluoride can be mentioned, and silicon dioxide is preferably used. In addition, the thickness of the inorganic oxide base layer 18 is preferably 50 nm or more, more preferably 65 nm or more, and further preferably 80 nm or more from the viewpoint of ensuring the peel resistance of the antifouling layer 15. The thickness of the inorganic oxide base layer 18 is, for example, 300 nm or less.

[0107] Examples

[0108] The following examples specifically illustrate the present invention. The present invention is not limited to the examples. In addition, the specific numerical values such as the compounding amount (content), physical property values, and parameters described below can be replaced with the corresponding compounding amount (content), physical property values, and parameters described in the above "Detailed Description" of the upper limit (the value defined as "below" or "less than") or the lower limit (the value defined as "above" or "more than").

[0109] 〔Example 1〕

[0110] The following processes were sequentially carried out to manufacture an optical film with an antifouling layer.

[0111] First, a hard coat is formed on one side of a polyethylene terephthalate (PET) film (thickness 50 μm) which is a transparent base film (hard coat forming step). Specifically, first, 100 parts by mass (in terms of solid content) of a butyl acetate solution (product name "UNIDIC 17-806", solid content concentration 80% by mass, manufactured by DIC Corporation) of a mixture of ultraviolet curable monomers and oligomers (containing urethane acrylate as the main component), 5 parts by mass of a photoinitiator (product name "IRGACURE 906", manufactured by BASF Corporation), and 0.01 part by mass of a leveling agent (product name "GRANDIC PC4100", manufactured by DIC Corporation) are mixed to obtain a mixed solution. Then, by adding a mixed solvent of cyclopentanone (CPN) and propylene glycol monomethyl ether (PGM) (mass ratio of CPN to PGM is 45:55), the solid content concentration of the mixed solution is adjusted to 36% by mass. Thus, a ultraviolet curable resin composition (varnish) is prepared. Next, the resin composition is coated on one side of the above PET film to form a coating film. Then, after drying the coating film by heating, it is cured by ultraviolet irradiation. The heating temperature is set at 90 °C and the heating time is set at 60 seconds. During ultraviolet irradiation, a high-pressure mercury lamp is used as the light source, ultraviolet light with a wavelength of 365 nm is used, and the cumulative irradiation light amount is set at 300 mJ / cm 2 . Thus, a hard coat (HC) with a thickness of 5 μm is formed on the PET film.

[0112] Next, using a roll-to-roll type plasma processing apparatus, the surface of the HC layer of the PET film with the HC layer is subjected to plasma processing in a vacuum atmosphere of 1.0 Pa (HC layer pretreatment step). In this plasma processing, argon is used as the inert gas and the discharge power is set at 780 W.

[0113] Next, an adhesion layer and an antireflection layer are sequentially formed on the HC layer of the PET film with an HC layer after plasma treatment (sputtering film formation process). Specifically, using a roll-to-roll sputtering film formation apparatus, an indium tin oxide (ITO) layer with a thickness of 1.5 nm as the adhesion layer, a Nb2O5 layer with a thickness of 12 nm as the first high refractive index layer, a SiO2 layer with a thickness of 28 nm as the first low refractive index layer, a Nb2O5 layer with a thickness of 100 nm as the second high refractive index layer, and a SiO2 layer with a thickness of 85 nm as the second low refractive index layer are sequentially formed on the HC layer of the PET film with an HC layer. In the formation of the adhesion layer, an ITO target is used, argon as an inert gas, and oxygen as a reactive gas at 10 parts by volume relative to 100 parts by volume of argon are used, the discharge voltage is set to 400 V, the gas pressure in the film formation chamber (film formation gas pressure) is set to 0.2 Pa, and an ITO layer is formed by MFAC sputtering (sputtering using an MFAC power supply as the power source). In the formation of the first high refractive index layer, a Nb target is used, 100 parts by volume of argon and 5 parts by volume of oxygen are used, the discharge voltage is set to 415 V, the film formation gas pressure is set to 0.42 Pa, and a Nb2O5 layer is formed by MFAC sputtering. In the formation of the first low refractive index layer, a Si target is used, 100 parts by volume of argon and 30 parts by volume of oxygen are used, the discharge voltage is set to 350 V, the film formation gas pressure is set to 0.3 Pa, and a SiO2 layer is formed by MFAC sputtering. In the formation of the second high refractive index layer, a Nb target is used, 100 parts by volume of argon and 13 parts by volume of oxygen are used, the discharge voltage is set to 460 V, the film formation gas pressure is set to 0.5 Pa, and a Nb2O5 layer is formed by MFAC sputtering. In the formation of the second low refractive index layer, a Si target is used, 100 parts by volume of argon and 30 parts by volume of oxygen are used, the discharge voltage is set to 340 V, the film formation gas pressure is set to 0.25 Pa, and a SiO2 layer is formed by MFAC sputtering. As described above, an antireflection layer (the first high refractive index layer, the first low refractive index layer, the second high refractive index layer, the second low refractive index layer) is laminated on the HC layer of the PET film with an HC layer by means of the adhesion layer.

[0114] Next, an antifouling layer is formed on the antireflection layer (antifouling layer formation process). Specifically, a vacuum evaporation method using an alkoxysilane compound containing a perfluoropolyether group as an evaporation source is used to form an antifouling layer with a thickness of 10 nm on the antireflection layer. The evaporation source is a solid component obtained by drying "KY1903-1" (an alkoxysilane compound containing a perfluoropolyether group, solid component concentration 20 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. In addition, the heating temperature of the evaporation source in the vacuum evaporation method is 260 °C.

[0115] While moving the workpiece film in a roll-to-roll manner, a series of processes from the HC layer pretreatment process to the antifouling layer formation process are carried out in a continuous production line. In this process, the workpiece film is not exposed to the atmosphere even once.

[0116] Next, a release film is attached to the exposed surface of the antifouling layer (first attachment process). Specifically, using a roll-to-roll type attachment device, the adhesive surface of the first release film having an adhesive surface on one side is attached to the surface of the antifouling layer. In the device used, the attachment pressure is set to 0.2 MPa. The first release film is produced as follows.

[0117] First, in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, a mixture containing 90 parts by mass of butyl acrylate (BA), 10 parts by mass of acrylic acid (AA), 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 234 parts by mass of ethyl acetate is stirred at 63°C for about 7 hours in a nitrogen atmosphere to cause a reaction (polymerization reaction). Thus, a first polymer solution (solid content concentration 30 mass%) containing a first acrylic polymer is obtained. Next, the polymer solution is diluted with ethyl acetate to 20 mass%. Next, after adding 11 parts by mass of an epoxy crosslinking agent (product name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Co., Inc.) relative to 100 parts by mass of the first acrylic polymer to the polymer solution, the solution is stirred at around 25°C for about 1 minute. Thus, an adhesive composition C1 is obtained. Next, the adhesive composition C1 is coated on one side of a polyethylene terephthalate (PET) substrate to form a coating film. Next, the coating film on the PET substrate is heated at 150°C for 60 seconds to form an adhesive layer with a thickness of 20 μm. Next, the silicone-treated surface of a PET release liner (thickness 25 μm) having been subjected to silicone treatment on one side is attached to the exposed surface of the adhesive layer. As described above, the first release film is produced. When using the first release film, the PET release liner is removed from the adhesive layer.

[0118] Next, the release film is peeled off from the antifouling layer by a roll-to-roll method (peeling process). The peeling speed in this process is set to 10 m / minute.

[0119] Next, a protective film is attached to the exposed surface of the antifouling layer (second attachment process). Specifically, using a roll-to-roll type attachment device, the adhesive surface of the first protective film having an adhesive surface on one side is attached to the surface of the antifouling layer. In the device used, the attachment pressure is set to 0.2 MPa. As the first protective film, the same film as the first release film is used.

[0120] As described above, an optical film (optical film with an antifouling layer) of Example 1 was produced. The optical film of Example 1 sequentially includes: a transparent substrate film, a hard coat layer, an adhesion layer, an antireflection layer, an antifouling layer, and a protective film.

[0121] 〔Example 2〕

[0122] Except for the following, the optical film of Example 2 was manufactured in the same manner as the optical film of Example 1. In the first lamination step, instead of the first release film, the second release film was used, and in the second lamination step, instead of the first protective film, the second protective film was used. The second release film was produced as follows (as the second protective film, a film produced in the same manner as the second release film was used).

[0123] First, an adhesive dispersion, a lubricant dispersion, and an aqueous conductive polymer solution were prepared. The adhesive dispersion was "VYLONAL MD-1480" manufactured by Toyobo Co., Ltd., which is an aqueous dispersion of a saturated copolyester resin as an adhesive, and the polyester resin concentration was 25% by mass. The lubricant dispersion was an aqueous dispersion of carnauba wax as a lubricant. The aqueous conductive polymer solution was "Baytron P" manufactured by H.C. Stark Co., Ltd., and contained 0.5% by mass of poly(3,4-ethylenedioxythiophene) (PEDT) as the first conductive polymer and 0.8% by mass of polystyrene sulfonate (number average molecular weight 150,000) (PSS) as the second conductive polymer. Next, 100 parts by mass of the adhesive dispersion, 30 parts by mass of the lubricant dispersion, 50 parts by mass of the aqueous conductive polymer solution, and a melamine-based crosslinking agent were added to a mixed solvent of water and ethanol, and stirred for about 20 minutes. Thus, a coating material having a solid content concentration of about 0.15% was obtained. In addition, a transparent polyethylene terephthalate (PET) film (thickness 38 μm, width 30 cm, length 40 cm) having been subjected to corona treatment on one side was prepared. Then, the above coating material was coated on the corona-treated surface of the PET film with a bar coater to form a coating film. Next, the coating film on the PET film was heated at 130°C for 2 minutes to dry it. In this way, a substrate (substrate with a surface coating) having a transparent surface coating with a thickness of 10 nm on one side of the PET film was produced.

[0124] On the other hand, in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, a mixture containing 100 parts by mass of 2-ethylhexyl acrylate, 4 parts by mass of 2-hydroxyethyl acrylate, 0.15 parts by mass of 2,2'-azobisisobutyronitrile (AIBN), and 200 parts by mass of toluene as a polymerization solvent was stirred at 70°C under a nitrogen atmosphere for 6 hours to cause a reaction (polymerization reaction). Thus, a second polymer solution containing a second acrylic polymer was obtained. Next, in this second polymer solution, 4 parts by mass of an isocyanate crosslinking agent (product name "CORONATE L", manufactured by Tosoh Corporation), 0.2 parts by mass of dibutyltin dilaurate (1% ethyl acetate solution) as a crosslinking catalyst, and toluene were added relative to 100 parts by mass of the second acrylic polymer, and then the solution was stirred at around 25°C for about 1 minute. Thus, an adhesive composition C2 (solid content concentration: 20% by mass) was obtained. Next, the adhesive composition C2 was coated on the silicone-treated surface of a PET release liner (thickness: 25 μm) having been subjected to silicone treatment on one side to form a coating film. Next, the coating film on the PET release liner was heated at 150°C for 60 seconds to form an adhesive layer with a thickness of 15 μm. Next, the surface of the above-mentioned substrate with the surface coating that was not provided with the surface coating was bonded to the exposed surface of the adhesive layer, and then cured (aged) for 3 days in an environment of 50°C and a relative humidity of 15%. As described above, a second release film (second protective film) was produced. When using this film, the PET release liner was removed from the adhesive layer.

[0125] 〔Example 3〕

[0126] Except for the following, the optical film of Example 3 was manufactured in the same manner as the optical film of Example 1. In the first bonding step, instead of the first release film, a third release film was used, and in the second bonding step, instead of the first protective film, a third protective film was used. The third release film was produced in the same manner as the above-mentioned second release film, except that the adhesive composition C3 was used instead of the adhesive composition C2. For the adhesive composition C3, the solid content concentration was changed from 20% by mass to 25% by mass, and the same operations as those for the adhesive composition C2 were performed to prepare it. As the third protective film, a film produced in the same manner as the third release film was used.

[0127] 〔Example 4〕

[0128] Except for the following, the optical film of Example 4 was manufactured in the same manner as the optical film of Example 1. In the first bonding step, instead of the first release film, a fourth release film was used, and in the second bonding step, instead of the first protective film, a fourth protective film was used. The fourth release film was produced as follows (as the fourth protective film, a film produced in the same manner as the fourth release film was used).

[0129] First, in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, a mixture containing 90 parts by mass of butyl acrylate (BA), 10 parts by mass of acrylic acid (AA), 0.1 part by mass of 2-hydroxyethyl acrylate (2HEA), 0.2 part by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and a specified amount of ethyl acetate was stirred at 55°C under a nitrogen atmosphere for about 8 hours to cause a reaction (polymerization reaction). Thus, a third polymer solution containing a third acrylic polymer (weight average molecular weight: 2.2 million) was obtained. Next, in this polymer solution, 0.8 part by mass of an isocyanate crosslinking agent (product name: "CORONATE L", manufactured by Tosoh Corporation) and 0.2 part by mass of a silane coupling agent (product name: "KBM403", manufactured by Shin-Etsu Chemical Co., Ltd.) were added and mixed with respect to 100 parts by mass of the third acrylic polymer. Thus, an adhesive composition C4 was obtained. Next, the adhesive composition C4 was applied to the silicone-treated surface of a first PET film (product name: "MRF38", thickness: 38 μm, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) serving as a release liner that had been treated on one side with silicone to form a coating film. Next, the coating film on the first PET film was heated at 155°C for 60 seconds to form an adhesive layer with a thickness of 23 μm. Next, a second PET film (thickness: 38 μm) that had not been treated with silicone was laminated to the exposed surface of the adhesive layer as a base material. As described above, a fourth release film was produced. When using the fourth release film, the first PET film serving as a release liner was removed from the adhesive layer.

[0130] 〔Example 5〕

[0131] An optical film of Example 5 was manufactured in the same manner as the optical film of Example 1, except for the following. In the first lamination step, instead of the first release film, a fifth release film was used, and in the second lamination step, instead of the first protective film, a fifth protective film was used. As the fifth release film, "TORAYFAN BS MS06" (resin film with an adhesive layer) manufactured by TORAY ADVANCED FILM Co., Ltd. was used. As the fifth protective film, the same film as the fifth release film was used.

[0132] 〔Example 6〕

[0133] An optical film of Example 6 was manufactured in the same manner as the optical film of Example 1, except that the thickness of the antifouling layer formed in the antifouling layer forming step was set to 5.7 nm instead of 10 nm.

[0134] 〔Example 7〕

[0135] The optical film of Example 7 was manufactured by operating in the same manner as the optical film of Example 1, except for the following. In the formation of the second low-refractive-index layer in the sputtering film-forming process, the film-forming pressure was set to 0.5 Pa instead of 0.25 Pa. In the antifouling layer formation process (vacuum evaporation method), the heating temperature of the evaporation source was set to 270 °C instead of 260 °C, and the thickness of the formed antifouling layer was set to 16.1 nm instead of 10 nm. In the first laminating process, the second release film was used instead of the first release film. In the second laminating process, the second protective film was used instead of the first protective film.

[0136] 〔Example 8〕

[0137] The optical film of Example 8 was manufactured by operating in the same manner as the optical film of Example 1, except for the following. In the formation of the second low-refractive-index layer in the sputtering film-forming process, the film-forming pressure was set to 0.5 Pa instead of 0.25 Pa. In the antifouling layer formation process (vacuum evaporation method), the heating temperature of the evaporation source was set to 245 °C instead of 260 °C, and the thickness of the formed antifouling layer was set to 16.8 nm instead of 10 nm. In the first laminating process, the second release film was used instead of the first release film. In the second laminating process, the second protective film was used instead of the first protective film.

[0138] 〔Example 9〕

[0139] The optical film of Example 9 was manufactured by operating in the same manner as the optical film of Example 1, except for the following. In the formation of the second low-refractive-index layer in the sputtering film-forming process, the film-forming pressure was set to 0.5 Pa instead of 0.25 Pa. A base layer pretreatment process was carried out between the sputtering film-forming process and the antifouling layer formation process. Specifically, using a roll-to-roll type plasma processing apparatus, the surface of the formed antireflection layer was subjected to plasma processing (processing gas: oxygen, discharge power: 50 W) in a vacuum atmosphere. In the antifouling layer formation process (vacuum evaporation method), the heating temperature of the evaporation source was set to 270 °C instead of 260 °C, and the thickness of the formed antifouling layer was set to 16.3 nm instead of 10 nm. In the first laminating process, the second release film was used instead of the first release film. In the second laminating process, the second protective film was used instead of the first protective film.

[0140] 〔Example 10〕

[0141] Except for the following, the optical film of Example 10 was manufactured in the same manner as the optical film of Example 1. In the formation of the second low-refractive-index layer in the sputtering film-forming process, the film-forming gas pressure was set to 0.5 Pa instead of 0.25 Pa. In the antifouling layer formation process (vacuum evaporation method), the heating temperature of the evaporation source was set to 270°C instead of 260°C, and the thickness of the formed antifouling layer was set to 17.0 nm instead of 10 nm. In the first laminating process, the third release film was used instead of the first release film. In the second laminating process, the third protective film was used instead of the first protective film.

[0142] 〔Comparative Example 1〕

[0143] Except for the following, the optical film of Comparative Example 1 was manufactured in the same manner as the optical film of Example 1. In the first laminating process, the sixth release film was used instead of the first release film, and in the second laminating process, the sixth protective film was used instead of the first protective film. As the sixth release film, “FSA020” (resin film with an adhesive layer) manufactured by FUTAMURA CHEMICAL CO., LTD. was used. As the sixth protective film, the same film as the sixth release film was used.

[0144] 〈Evaluation of Adhesive Strength〉

[0145] The adhesive strength of the release film adhered to the antifouling layer in each manufacturing method of Examples 1 to 10 and Comparative Example 1 was studied. Specifically, first, during the manufacture of the optical film, a film piece (50 mm × 100 mm) was cut out from the workpiece film (optical film with a release film) after the first laminating process. Next, the surface on the side of the transparent substrate film of the film piece was attached to a glass plate by means of a prescribed adhesive layer (this adhesive layer was an adhesive layer formed from the above-mentioned adhesive composition C4). Thereby, a measurement specimen was obtained. Next, a peeling test of peeling the release film from the measurement specimen was carried out, and the peeling strength was measured as the adhesive strength (N / 50 mm). In this measurement, a tensile testing machine (product name “Autograph AG-X plus”, manufactured by Shimadzu Corporation) was used. In this measurement, the measurement temperature was set to 25°C, the peeling angle of the release film with respect to the surface of the antifouling layer was set to 180°, the tensile speed of the release film was set to 30 cm / minute, and the peeling length was set to 50 mm. The results are shown in Table 1. It is considered that in each optical film, the adhesive strength of the protective film to the antifouling layer is the same as the measured adhesive strength of the release film to the antifouling layer.

[0146] 〈F Strength Ratio of Antifouling Layer〉

[0147] Measure the F intensity ratio R0 of the antifouling layer before the first lamination step and the F intensity ratio R1 of the antifouling layer after the peeling step in each manufacturing method of Examples 1 to 10 and Comparative Example 1. In addition, measure the F intensity ratio R2 of the antifouling layer after removing the protective film from the manufactured optical film. The F intensity ratio is the ratio of the X-ray intensity (F intensity) of fluorine (F) obtained by fluorescence X-ray analysis of the film to be measured under specified conditions to the X-ray intensity of fluorine (F) obtained by fluorescence X-ray analysis of glass containing 4.96 mass% fluorine atoms as a standard sample under the same conditions. In this measurement, a scanning-type fluorescence X-ray analyzer (product name "ZSX PrimusII", manufactured by Rigaku Corporation) is used. In this measurement, "XRF-PF3" manufactured by LGC Standards is used as the standard sample, and the fluorine atom intensity in the surface layer and the fluorine atom intensity in the standard sample are measured separately under the conditions of measurement diameter: 30 mm, measurement ray: F-Kα, filter: OUT, slit: standard, spectroscopic crystal: RX35 (manufactured by Rigaku Corporation), detector: PC, PHA: 100 - 300, peak angle: 38.794 deg. (20 sec), B.G. angle: 43.000 deg. (10 sec). The F intensity ratios R0, R1, R2, the ratio of the F intensity ratio R1 to the F intensity ratio R0 (R1 / R0), and the ratio of the F intensity ratio R2 to the F intensity ratio R1 (R2 / R1) are shown in Table 1. The ratio of the F intensity ratio (R1 / R0) reflects the ratio (T1 / T0) of the thickness T1 of the antifouling layer after the peeling step to the thickness T0 of the antifouling layer before the first lamination step. That is, the ratio of the F intensity ratio (R1 / R0) is the same as the thickness ratio (T1 / T0). In addition, the ratio of the F intensity ratio (R2 / R1) reflects the ratio (T2 / T1) of the thickness T2 of the antifouling layer after removing the protective film to the thickness T1 of the antifouling layer after the peeling step. That is, the ratio of the F intensity ratio (R2 / R1) is the same as the thickness ratio (T2 / T1).

[0148] 〈Transparent appearance〉

[0149] After the second lamination step in each manufacturing method of Examples 1 to 10 and Comparative Example 1, evaluate the transparent appearance of the antifouling layer. Specifically, first, visually observe the surface of the antifouling layer through the protective film to confirm whether a cloudy portion is formed, resulting in color unevenness. For the visual observation, perform the observation from a direction with an elevation angle of approximately 20° relative to the surface of the antifouling layer. Then, for the transparent appearance of the antifouling layer, evaluate as "good" when no color unevenness occurs, and evaluate as "bad" when color unevenness occurs. The results are shown in Table 1.

[0150] 〈Antifouling durability〉

[0151] The durability of the antifouling layers of the optical films in Research Examples 1 to 10 and Comparative Example 1 was investigated as follows. First, after removing the protective film from the optical film, the water contact angle of the antifouling layer surface was measured. Then, a rubber sliding test was performed on the antifouling layer surface. After that, the water contact angle of the antifouling layer surface was measured again. In the measurement of the water contact angle before and after the rubber sliding test, first, a water droplet was formed by dropping approximately 1 μL of pure water on the antifouling layer surface of the optical film. Then, the angle formed by the surface of the water droplet on the antifouling layer surface and the antifouling layer surface was measured. A contact angle meter (product name “DMo-501”, manufactured by Kyowa Interface Science Co., Ltd.) was used for the measurement. In the rubber sliding test, a rubber (Φ6 mm) manufactured by Minoan was used. The load of the rubber on the antifouling layer surface was set to 1 kg / 6 mmΦ, the sliding distance (one-way of the round-trip sliding) of the rubber on the antifouling layer surface was set to 20 mm, the sliding speed of the rubber was set to 40 round-trips per minute, and the number of round-trips of the rubber sliding on the antifouling layer surface was set to 3000 round-trips.

[0152] On the antifouling layer surface, the degree of decrease in the water contact angle caused by the rubber sliding test indicates the degree of decrease in antifouling performance. Regarding the antifouling durability of the antifouling layer, when the decrease in the water contact angle caused by the rubber sliding test is less than 15°, it is evaluated as “excellent”. When it is 15° or more and less than 20°, it is evaluated as “good”. When it is 20° or more, it is evaluated as “poor”. The results are shown in Table 1.

[0153] [Table 1]

[0154]

Claims

1. A method for manufacturing an optical film with an antifouling layer, which is a method for manufacturing an optical film with an antifouling layer by a roll-to-roll method, The manufacturing method includes: An antifouling layer forming step of forming an antifouling layer on one side in the thickness direction of a transparent substrate film; A first laminating step of laminating the adhesive surface of a release film having an adhesive surface on the antifouling layer; A peeling step of peeling the release film from the antifouling layer; And A second laminating step of laminating the adhesive surface of a protective film having an adhesive surface on the antifouling layer, The adhesive force of the release film to the antifouling layer is 0.015 N / 50 mm or more and 0.1 N / 50 mm or less, The protective film can be peeled off from the antifouling layer.

2. The manufacturing method of the optical film with an anti-fouling layer according to claim 1, wherein, In the antifouling layer forming step, the antifouling layer is formed by a dry coating method.

3. An optical film with an antifouling layer, which sequentially includes: a transparent substrate film, an antifouling layer, and a protective film, The protective film has an adhesive surface on the antifouling layer side and is adhered to the antifouling layer with the adhesive surface, The adhesive force of the protective film to the antifouling layer is 0.015 N / 50 mm or more and 0.1 N / 50 mm or less, The protective film can be peeled off from the antifouling layer, and the ratio of the thickness of the antifouling layer after removing the protective film to the thickness of the antifouling layer in the state where the protective film is provided is 0.92 or more and 1.0 or less, The F intensity ratio of the antifouling layer after removing the protective film is 0.18 or more and 0.98 or less, and the F intensity ratio is: the ratio of the X-ray intensity (F intensity) of fluorine (F) obtained by fluorescent X-ray analysis for the antifouling layer to the X-ray intensity (F intensity) of fluorine (F) obtained by fluorescent X-ray analysis under the same conditions as the fluorescent X-ray analysis for a glass as a standard sample containing 4.96 mass% fluorine atoms.

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