Optical film

Abstract

To provide an optical film capable of realizing both an antibacterial and antiviral property and other properties.SOLUTION: An optical film 10 comprises a base material 20, an antibacterial and antiviral layer 21 containing a silver-based antibacterial and antiviral agent, and a coating layer 22 covering the antibacterial and antiviral layer 21. A face opposite to the antibacterial and antiviral layer 21 on the coating layer 22 is a surface of the optical film 10, having an eluted Ag ion amount of 20 ng / cm2 or more per unit area when keeping the surface in close contact with pure water for 24 hours.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to optical films. [Background technology]

[0002] Optical films have the function of controlling light reflection, transmission, etc. For example, optical films are disposed on the surface of a display device in order to make the screen of the display device easier to view.

[0003] In addition to optical properties such as haze, optical films are required to have various properties such as hardness, scratch resistance, antifouling property, slipperiness, etc., depending on the application. Furthermore, due to the recent increase in hygiene awareness, there is an increasing demand for optical films having antibacterial and antiviral properties.

[0004] For example, Patent Document 1 describes an optical film that exhibits antibacterial properties while suppressing deterioration in optical properties and hardness by controlling the average particle size of the antibacterial agent such as silver and fine particles contained in the film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6720639 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to impart antibacterial and antiviral properties to an optical film, it is necessary to increase the content of functional components such as silver having antibacterial and antiviral properties in the film. However, the more the content of the functional components is increased, the more difficult it becomes to obtain other properties in addition to antibacterial and antiviral properties in the optical film. In particular, in order to improve the function of the optical film, it is preferable to obtain many properties well, but the more properties to be imparted, the more difficult it becomes to achieve antibacterial and antiviral properties at the same time. [Means for solving the problem]

[0007] Various aspects of the antiviral film for solving the above problems will be described below. [Aspect 1] An optical film comprising a substrate, an antibacterial and antiviral layer supported on the substrate, and a coating layer covering the antibacterial and antiviral layer on a side opposite the substrate with respect to the antibacterial and antiviral layer, wherein the antibacterial and antiviral layer contains a resin component and a silver-based antibacterial and antiviral agent, the coating layer contains a resin component, the side of the coating layer opposite the antibacterial and antiviral layer is a surface of the optical film, and when the surface is brought into contact with pure water for 24 hours, the amount of Ag ions eluted per unit area of ​​the surface is 20 ng / cm 2 That's it for the optical film.

[0008] According to the above-mentioned configuration, since the antibacterial and antiviral layer is covered with the coating layer, the decrease in properties other than the antibacterial and antiviral properties due to the inclusion of the silver-based antibacterial and antiviral agent is compensated for by the coating layer. 2 For the above reasons, even if the antibacterial and antiviral layer is covered with a coating layer, sufficient antibacterial and antiviral properties can be obtained. Therefore, it is possible to achieve both antibacterial and antiviral properties and other properties.

[0009] [Aspect 2] The optical film according to [Aspect 1], wherein the antibacterial and antiviral layer contains fine particles in addition to the silver-based antibacterial and antiviral agent. According to the above configuration, it is possible to adjust the light scattering properties of the optical film.

[0010] [Aspect 3] The optical film according to [Aspect 1] or [Aspect 2], wherein the resin component contained in the antibacterial and antiviral layer is either a thermosetting resin or an ultraviolet-curing resin. According to the above-mentioned configuration, it is easy to form the antibacterial and antiviral layer and the materials can be easily obtained.

[0011] [Aspect 4] The optical film according to any one of [Aspect 1] to [Aspect 3], wherein the resin component contained in the coating layer is either a thermosetting resin or an ultraviolet-curing resin. According to the above-mentioned configuration, it is easy to form the covering layer and the materials are easily available.

[0012] [Aspect 5] The optical film according to any one of [Aspects 1] to 4], wherein the resin component contained in the antibacterial and antiviral layer and the resin component contained in the coating layer are each an ultraviolet-curable resin.

[0013] According to the above configuration, the adhesion between the antibacterial and antiviral layer and the coating layer is improved, and the versatility of the optical film is increased. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide an optical film that has both antibacterial and antiviral properties and other properties. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view showing a layer structure of an optical film according to one embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing a part of the optical film of one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of the optical film will be described with reference to the drawings. [Optical film layer structure] 1, the optical film 10 includes a substrate 20, an antibacterial and antiviral layer 21, and a coating layer 22. The antibacterial and antiviral layer 21 contains an antibacterial and antiviral component and a resin component. The coating layer 22 contains a resin component, but does not contain an antibacterial and antiviral component.

[0017] The substrate 20 supports the antibacterial and antiviral layer 21. The coating layer 22 is located on the opposite side of the substrate 20 with respect to the antibacterial and antiviral layer 21, and covers the antibacterial and antiviral layer 21. That is, the lower surface of the antibacterial and antiviral layer 21 is in contact with the substrate 20, and the upper surface of the antibacterial and antiviral layer 21 is in contact with the coating layer 22.

[0018] The upper surface of the coating layer 22 opposite to the lower surface in contact with the antibacterial and antiviral layer 21 is the surface of the optical film 10. The surface of the optical film 10 is an active surface that exhibits antibacterial and antiviral activity.

[0019] The structure of each layer will now be described in detail. <Base material> The material and thickness of the substrate 20 may be any material and thickness that can form the antibacterial and antiviral layer 21 on the substrate 20. The substrate 20 is, for example, a resin film. Examples of materials for the resin film include polyester, polypropylene, polystyrene, nylon, polycarbonate, polyacrylonitrile, polyimide, triacetyl cellulose, etc. From the viewpoint of easy handling of the substrate 20, the thickness of the substrate 20 is preferably 12 μm or more, and more preferably 20 μm or more. If the thickness of the substrate 20 is 12 μm or more, the mechanical strength and quality of the substrate 20 are easily obtained. The substrate 20 may be a single-layer structure or a multi-layer structure.

[0020] <Antibacterial and antiviral layer> The resin component contained in the antibacterial and antiviral layer 21 may be a thermosetting resin or an ultraviolet-curing resin. Examples of the thermosetting resin include acrylic resin, urethane resin, and epoxy resin. The ultraviolet-curing resin is a cured product of a photopolymerizable compound. Examples of the photopolymerizable compound include monofunctional, bifunctional, or trifunctional or higher functional (meth)acrylate compounds and urethane (meth)acrylate compounds. Note that "(meth)acrylate" is a general term for acrylate and methacrylate.

[0021] The antibacterial and antiviral component contained in the antibacterial and antiviral layer 21 is a silver-based antibacterial and antiviral agent. The silver-based antibacterial and antiviral agent may be a silver-supported carrier, silver particles, or silver compound particles. When it is required to enhance the stability of the silver-based antibacterial and antiviral agent, the silver-based antibacterial and antiviral agent is preferably a silver-supported carrier consisting of a carrier and silver supported on the carrier.

[0022] Examples of the material of the carrier constituting the silver-loaded carrier include porous carriers such as zinc calcium phosphate, calcium phosphate, zirconium phosphate, aluminum phosphate, calcium silicate, activated carbon, alumina, silica gel, zeolite, hydroxyapatite, titanium phosphate, potassium titanate, hydrated bismuth oxide, hydrated zirconium oxide, and hydrotalcite, and glass-based materials such as magnesium-aluminum phosphate glass, magnesium-calcium-phosphate-borate glass, zinc-magnesium-aluminum-calcium-sodium-borate-phosphate glass, magnesium-sodium-phosphate glass, and magnesium-zinc-aluminum-calcium-sodium-borate-phosphate glass. From the viewpoint of increasing the stability of particle size distribution, the dispersibility of the silver-based antibacterial and antiviral agent, and the stability of antibacterial activity and antiviral activity, it is preferable that the material of the carrier is at least one selected from the group consisting of zinc calcium phosphate, calcium phosphate, and zeolite.

[0023] The average particle diameter of the silver-supported carrier is a volume-based median diameter (D50). From the viewpoint of enhancing antibacterial activity, antiviral activity, and dispersibility, the average particle diameter of the silver-supported carrier is preferably 3 μm or less, and more preferably 1 μm or less. If the average particle diameter of the silver-supported carrier is 3 μm or less, the influence of the silver-based antibacterial and antiviral agent on the optical properties such as haze in the optical film 10 can be reduced. The average particle diameter of the silver-supported carrier may be larger than the thickness of the antibacterial and antiviral layer 21, may be smaller than the thickness of the antibacterial and antiviral layer 21, or may be equal to the thickness of the antibacterial and antiviral layer 21. The average particle diameter of the silver-supported carrier may be larger than the thickness of the coating layer 22, may be smaller than the thickness of the coating layer 22, or may be equal to the thickness of the coating layer 22.

[0024] From the viewpoint of enhancing antibacterial and antiviral activity, the ratio of the mass of the silver-based antibacterial and antiviral agent to the total mass of the antibacterial and antiviral layer 21 is preferably 3 mass% or more, and more preferably 5 mass% or more. From the viewpoint of enhancing dispersibility of the silver-based antibacterial and antiviral agent, the ratio of the mass of the silver-based antibacterial and antiviral agent to the total mass of the antibacterial and antiviral layer 21 is preferably 30 mass% or less, and more preferably 20 mass% or less.

[0025] The antibacterial and antiviral layer 21 may contain fine particles for adjusting the light scattering properties of the optical film 10. The inclusion of fine particles makes it possible to adjust the surface roughness of the upper surface of the antibacterial and antiviral layer 21, and thus the surface roughness of the surface of the optical film 10. By adjusting the surface roughness, it is possible to control the light scattering properties of the surface of the optical film 10. If the surface of the optical film 10 has an appropriate light scattering property, it is possible to increase the diffuse reflection component in the light reflected on the surface of the optical film 10 and suppress the specular reflection component, thereby suppressing the reflection of the surroundings on the optical film 10.

[0026] The inclusion of fine particles also makes it possible to control the light scattering properties inside the antibacterial and antiviral layer 21. By controlling the light scattering properties on the surface of the optical film 10 and inside the antibacterial and antiviral layer 21, it is possible to control the haze of the optical film 10, and thus the transparency of the optical film 10 can be adjusted.

[0027] The fine particles are organic fine particles or inorganic fine particles. The fine particles contained in the antibacterial and antiviral layer 21 may be one type, or may be two or more types that are different from each other in at least one of the material and the average particle size. The average particle size of the fine particles is a volume-based median size (D50). The average particle size of the fine particles is preferably 30% or more of the thickness of the antibacterial and antiviral layer 21, and more preferably 50% or more and 80% or less of the thickness of the antibacterial and antiviral layer 21. The thickness of the antibacterial and antiviral layer 21 is the film thickness of a portion of the antibacterial and antiviral layer 21 that does not contain the silver-based antibacterial and antiviral agent and the fine particles in the thickness direction. The content ratio of the fine particles in the antibacterial and antiviral layer 21 is preferably 3.0% by mass or more and 20% by mass or less. If the content ratio of the fine particles is 3.0% by mass or more, the effect of scattering light by the fine particles can be suitably obtained. If the content ratio of the fine particles is 20% by mass or less, the resin component does not become too small, so that a decrease in the strength of the antibacterial and antiviral layer 21 is suppressed.

[0028] The organic fine particles are resin particles made of a light-transmitting resin material such as acrylic resin, polystyrene resin, styrene-(meth)acrylic acid ester copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride, or polyethylene fluoride resin.

[0029] Inorganic fine particles can be used as a material for adjusting the sedimentation or aggregation of organic fine particles. Examples of inorganic fine particles include silica fine particles, metal oxide fine particles, and mineral fine particles. Examples of silica fine particles include colloidal silica and silica fine particles surface-modified with reactive functional groups such as (meth)acryloyl groups. Examples of metal oxides constituting metal oxide fine particles include aluminum oxide, zinc oxide, tin oxide, antimony oxide, indium oxide, titanium dioxide, and zirconium dioxide. Examples of minerals constituting mineral fine particles include mica, synthetic mica, vermiculite, montmorillonite, iron montmorillonite, bentonite, beidellite, saponite, hectorite, stevensite, nontronite, magadiite, ilealite, kanemite, layered titanic acid, smectite, and synthetic smectite.

[0030] The thickness of the antibacterial and antiviral layer 21 is preferably 0.5 μm or more, and more preferably 1 μm or more, from the viewpoints of improving the uniformity of the thickness of the antibacterial and antiviral layer 21, the applicability of the coating liquid for forming the antibacterial and antiviral layer 21, the mechanical durability, and the antibacterial and antiviral activities of the antibacterial and antiviral layer 21. The thickness of the antibacterial and antiviral layer 21 is preferably 10 μm or less, and more preferably 5 μm or less, from the viewpoints of improving the adhesion of the antibacterial and antiviral layer 21 to the substrate 20 and reducing the load required for curing the antibacterial and antiviral layer 21.

[0031] The thickness of the antibacterial and antiviral layer 21 is the film thickness of the portion of the antibacterial and antiviral layer 21 that does not contain the silver-based antibacterial and antiviral agent or microparticles in the thickness direction. The thickness of the optical film 10 and each layer constituting the optical film 10 is the average value of the sample thickness values ​​in the cross section of the object to be measured. The sample thickness value is a measurement value that is within 50% of the average value of thickness measurements taken at 10 points spaced 1 mm or more apart in the cross section of the object to be measured.

[0032] The antibacterial and antiviral layer 21 may contain various additives. Examples of additives are ultraviolet absorbing agents, antistatic agents, leveling agents, thickeners, etc. The inclusion of additives can enable the antibacterial and antiviral layer 21 to exhibit ultraviolet absorbing functions, antistatic functions, etc., and improve coatability and quality.

[0033] The antibacterial and antiviral layer 21 is formed by applying an antibacterial and antiviral layer coating liquid, which is a coating liquid for forming the antibacterial and antiviral layer 21, to the upper surface of the substrate 20 and curing the film thus formed. The antibacterial and antiviral layer coating liquid contains auxiliary agents as required, such as a compound for forming the resin component of the antibacterial and antiviral layer 21, a silver-based antibacterial and antiviral agent, and a polymerization initiator. When forming the antibacterial and antiviral layer 21 containing fine particles, the antibacterial and antiviral layer coating liquid further contains fine particles.

[0034] The coating liquid for the antibacterial and antiviral layer can be applied by any known method such as bar coating, spin coating, offset coating, gravure coating, roll coating, die coating, etc. The method for curing the film after application may be any method appropriate for the curing type of the resin component, and heat drying or ultraviolet irradiation is used.

[0035] <Coating layer> The resin component contained in the coating layer 22 may be a thermosetting resin or an ultraviolet curing resin. As the thermosetting resin and the ultraviolet curing resin, for example, the resins exemplified as the material of the antibacterial and antiviral layer 21 are used. The resin component contained in the coating layer 22 may be the same as or different from the resin component contained in the antibacterial and antiviral layer 21. When the resin components of the antibacterial and antiviral layer 21 and the coating layer 22 are the same type of resin, the adhesion between the antibacterial and antiviral layer 21 and the coating layer 22 is enhanced.

[0036] The thickness of the coating layer 22 is preferably 0.01 μm or more, more preferably 0.3 μm or more, and even more preferably 1 μm or more, from the viewpoints of improving the uniformity of the thickness of the coating layer 22, the applicability of the coating liquid for forming the coating layer 22, and the mechanical durability of the coating layer 22. The thickness of the coating layer 22 is preferably 20 μm or less, and more preferably 5 μm or less, from the viewpoints of improving the adhesion of the coating layer 22 to the antibacterial and antiviral layer 21 and the antibacterial and antiviral activities of the coating layer 22 and reducing the load required for curing the coating layer 22.

[0037] The thickness of the coating layer 22 may be smaller than the thickness of the antibacterial and antiviral layer 21, may be larger than the thickness of the antibacterial and antiviral layer 21, or may be equal to the thickness of the antibacterial and antiviral layer 21. The thickness of the coating layer 22 is the film thickness of the coating layer 22 in the portion of the optical film 10 that does not contain the silver-based antibacterial and antiviral agent and the fine particles in the thickness direction.

[0038] The coating layer 22 may contain various additives. Examples of additives include antifouling agents, ultraviolet absorbing agents, antistatic agents, refractive index adjusting agents, and light scattering adjusting agents. Antifouling agents include leveling agents, agents for imparting oil repellency or water repellency, and agents for preventing fingerprints.

[0039] The coating layer 22 is formed by applying a coating layer coating liquid, which is a coating liquid for forming the coating layer 22, onto the upper surface of the antibacterial and antiviral layer 21 and curing the film thus formed. The coating layer coating liquid contains a compound for forming the resin component of the coating layer 22 and an auxiliary agent as necessary.

[0040] The coating liquid for the coating layer can be applied by a known method such as bar coating, spin coating, offset coating, gravure coating, roll coating, die coating, etc. The method for curing the applied film may be any method that corresponds to the curing type of the resin component, and may include heating and drying or ultraviolet irradiation.

[0041] [Optical film characteristics] The amount of Ag elution Ev in the optical film 10 will be described. The amount of Ag elution Ev is the amount of Ag ions eluted per unit area of ​​the surface of the optical film 10 when the surface of the optical film 10 is in contact with pure water for 24 hours. The surface of the optical film 10 is the upper surface of the coating layer 22. In the optical film 10 of this embodiment, the amount of Ag elution Ev is 20 ng / cm 2 This provides sufficient antibacterial and antiviral effects.

[0042] Specifically, the amount of eluted Ag Ev is measured by the following steps (a) to (d). (a) A test piece is prepared by forming the optical film 10 into a square shape with each side measuring 5 cm, and 0.4 mL of pure water is dropped onto the surface of the test piece. Then, a square polyethylene film with each side measuring 4 cm is attached to the surface of the test piece after the pure water has been dropped. As a result, the area of ​​the test piece surface that is covered by the polyethylene film is uniformly wetted with pure water, making it possible to uniformly extract the eluted components. Therefore, the area to be measured for the amount of Ag elution Ev is 16 cm2, which corresponds to the area covered by the polyethylene film. 2 It is.

[0043] (b) The test piece after the treatment in (a) above is placed in a petri dish, and the petri dish is placed in an environment of temperature: 35±1°C and humidity: 90% RH or higher to extract the eluted components for 24 hours. (c) After the above process (b), the extractant adhering to the surface of the test piece is collected. Specifically, a predetermined amount of pure water for washing is added to the surface of the test piece, and then the mixture of the extractant and the pure water for washing is collected. The collected mixture is then diluted with dilute nitric acid to obtain a measurement solution for measuring the amount of Ag elution Ev.

[0044] (d) The amount of Ag ions in the measurement solution obtained by the process in (c) above is measured using atomic absorption spectrometry. Based on the measurement results, the amount of Ag ions eluted per unit area is calculated using the following (Equation 1), and this is taken as the amount of eluted Ag, Ev. Ag elution amount Ev (ng / cm 2 ) = Ag ion quantitative result in the measurement solution (ng / mL) × volume of recovered solution (mL) × dilution ratio of recovered solution / measurement area (cm 2 )...(Formula 1)

[0045] The action of the optical film 10 of this embodiment will be described with reference to Fig. 2. Fig. 2 shows a schematic diagram of an example of the state in which the silver-based antibacterial and antiviral agent is contained in the optical film 10 of this embodiment.

[0046] 2, in the optical film 10 of this embodiment, the coating layer 22 covers the antibacterial and antiviral layer 21, including the functional particles Pm, which are particles of a silver-based antibacterial and antiviral agent. Therefore, regardless of the content of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer 21, the properties of the optical film 10, such as hardness, scratch resistance, antifouling property, slipperiness, pure water contact angle, and reflectance, can be favorably obtained by controlling the properties of the coating layer 22 to a desired level. In particular, the properties related to the surface state of the optical film 10 can be controlled by the surface state of the coating layer 22, and therefore the desired properties can be easily obtained.

[0047] When the optical film does not have the coating layer 22, the characteristics related to the surface state of the optical film are deteriorated due to the inclusion of the functional particles Pm, particularly when the average particle diameter of the functional particles Pm is larger than the thickness of the antibacterial and antiviral layer 21. In contrast, with the optical film 10 of the present embodiment, even if the average particle diameter of the functional particles Pm is larger than the thickness of the antibacterial and antiviral layer 21, the characteristics related to the surface state of the optical film 10 can be favorably obtained.

[0048] Specifically, the provision of the coating layer 22 can ensure a sufficient ratio of the resin component near the surface of the optical film 10, thereby improving hardness. In addition, the coating layer 22 smooths out the unevenness on the upper surface of the antibacterial and antiviral layer 21 caused by the functional particles Pm, thereby improving anti-fouling properties such as the ease of wiping off fingerprints, and slipperiness.

[0049] Here, the antibacterial and antiviral activities are exhibited when Ag ions eluted from the film act on bacteria and viruses, and so it was previously thought that the antibacterial and antiviral effects of the optical film 10 could not be obtained unless the functional particles Pm were exposed on the surface of the optical film 10. For this reason, a structure in which the antibacterial and antiviral layer 21 is disposed on the outermost surface of the optical film is adopted, and even when the antibacterial and antiviral layer 21 is covered with another layer, the Ag ions are made to easily elute by forming a passage for the Ag ions in the other layer, for example, by a polymer having a hydrophilic group in a fluoropolymer.

[0050] In contrast, as a result of intensive research by the inventors of the present application, it was found that the Ag elution amount Ev is 20 ng / cm 2 As described above, it has been confirmed that sufficient antibacterial and antiviral effects can be obtained even in an optical film 10 in which the functional particles Pm are covered with a coating layer 22, and even if the coating layer 22 is not formed from a specific material such as a fluoropolymer and a polymer having a hydrophilic group. Therefore, a high degree of freedom is available for the material of the coating layer 22, making it easy to control properties other than the antibacterial and antiviral properties, and it is possible to achieve both the antibacterial and antiviral properties and other properties at the same time.

[0051] In the optical film 10 of this embodiment, if the average particle diameter of the functional particles Pm is larger than the sum of the thickness of the antibacterial and antiviral layer 21 and the thickness of the coating layer 22, it is easy to obtain a high amount of Ag elution Ev while obtaining favorable properties other than the antibacterial and antiviral properties, and therefore the antibacterial and antiviral properties are enhanced. On the other hand, when the average particle diameter of the functional particles Pm is larger than the thickness of the antibacterial and antiviral layer 21, if the average particle diameter of the functional particles Pm is smaller than the sum of the thickness of the antibacterial and antiviral layer 21 and the thickness of the coating layer 22, the influence of the inclusion of a silver-based antibacterial and antiviral agent on the surface of the optical film 10, for example, on unevenness, can be reduced.

[0052] The optical film 10 of the present embodiment is suitable for use in a display device. The rear surface of the optical film 10 is attached to a display surface of the display device. The display surface is the surface of a display panel such as a liquid crystal panel or an organic EL panel, or the surface of a touch panel laminated on the display panel.

[0053] By using the optical film 10 in a display device, it is possible to protect the display surface from dirt and scratches, and to maintain the display surface easy to see. In addition, by using the optical film 10 having the desired haze and antireflection properties, it is possible to adjust the visibility of the displayed image.

[0054] Furthermore, when the display surface is the surface of a touch panel, users will frequently touch the display device, and therefore it is highly beneficial for the optical film 10 to have antibacterial and antiviral properties.

[0055] Specific examples of display devices include smartphones, tablet terminals, personal computers, portable game consoles, music playback devices, televisions, monitors, e-book viewing devices, digital cameras, head-mounted displays, navigation devices, copiers, facsimiles, printers, multi-function printers, vending machines, automated teller machines (ATMs), personal authentication devices, and optical communication equipment.

[0056] [Example] The above-mentioned optical film will be described with reference to specific examples and comparative examples. Example 1 Preparation of antibacterial and antiviral coating solution A base agent containing an acrylic compound (UC Clear: manufactured by DIC Corporation) and a urethane curing agent containing an isocyanate (W-325N: manufactured by DIC Corporation) were used, and the base agent and the curing agent were mixed so that the dry weight ratio of the base agent to the curing agent was base agent:curing agent=10.0:1.7. A silver-based antibacterial and antiviral agent (PTC-NTANV Additive ST: manufactured by Dainichiseika Chemicals Co., Ltd., silver loading amount: 3 mass%, average particle size: 3 μm (volume-based median size)) was added to this mixture so that the proportion of the silver-based antibacterial and antiviral agent in the solid content of the coating liquid was 5.0 mass%. At this time, ethyl acetate was used as a solvent, and the solvent was added so that the solid content concentration in the coating liquid was 0.08 mass%, and the mixture was thoroughly mixed using a magnetic stirrer to produce an antibacterial and antiviral layer coating liquid.

[0057] Preparation of coating layer coating solution A base agent containing an acrylic compound (UC Clear: manufactured by DIC Corporation) and a urethane curing agent containing an isocyanate (W-325N: manufactured by DIC Corporation) were used, and the base agent and the curing agent were mixed so that the dry weight ratio of the base agent to the curing agent was base agent:curing agent = 10.0:1.7. At this time, ethyl acetate was used as a solvent, and a solvent was added so that the solid content concentration in the coating liquid was 0.08 mass%, and the coating layer coating liquid was generated by thoroughly mixing using a magnetic stirrer.

[0058] - Formation of antibacterial and antiviral layers and coating layers A biaxially stretched film made of polyethylene terephthalate (Cosmoshine A4260: manufactured by Toyobo Co., Ltd., thickness: 50 μm) cut into A4 size was used as the substrate. 1 mL to 2 mL of the antibacterial and antiviral layer coating liquid was dropped onto the substrate with a dropper, and the antibacterial and antiviral layer coating liquid was applied to the substrate with a #18 bar of a wireless bar coater (A-Bar: manufactured by Mitsui Electric Seiki Co., Ltd.). The coated film was dried for 1 minute in an atmospheric oven heated to 80°C to form an antibacterial and antiviral layer.

[0059] After the antibacterial and antiviral layer was sufficiently dried, 1 mL to 2 mL of the coating layer coating liquid was dropped onto the upper surface of the antibacterial and antiviral layer with a dropper, and the coating layer coating liquid was applied to the antibacterial and antiviral layer with a #18 bar of a wireless bar coater (A-Bar: manufactured by Mitsui Electric Seiki Co., Ltd.) The coated film was dried for 1 minute in an atmospheric oven heated to 80°C to form a coating layer.

[0060] The laminate consisting of the substrate, the antibacterial and antiviral layer, and the coating layer was left to stand in a thermostatic chamber at a temperature of 40°C and a humidity of 20% RH for 96 hours to age the coating film. This resulted in the optical film of Example 1. In Example 1, the antibacterial and antiviral layer had a thickness of 1.0 μm, the coating layer had a thickness of 1.0 μm, and the content of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 5.0 mass%.

[0061] Example 2 The optical film of Example 2 was obtained using the same materials and steps as in Example 1, except that the amount of the silver-based antibacterial and antiviral agent added in the antibacterial and antiviral layer coating liquid was changed to 15.0 mass % of the solid content in the coating liquid, and that the coating layer coating liquid was repeatedly applied five times using a #18 bar of a wireless bar coater (A-Bar: manufactured by Mitsui Electric Seiki Co., Ltd.) when forming the coating layer. In Example 2, the thickness of the antibacterial and antiviral layer was 1.0 μm, the thickness of the coating layer was 5.0 μm, and the content ratio of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 15.0 mass %.

[0062] Example 3 Except for changing the amount of the silver-based antibacterial and antiviral agent added in the antibacterial and antiviral layer coating liquid to 20.0 mass % of the solid content in the coating liquid, an optical film of Example 3 was obtained using the same materials and steps as in Example 1. In Example 3, the thickness of the antibacterial and antiviral layer was 1.0 μm, the thickness of the coating layer was 1.0 μm, and the content of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 20.0 mass %.

[0063] Example 4 Preparation of antibacterial and antiviral coating solution An antibacterial and antiviral layer coating liquid was produced using the same materials and steps as in Example 1, except that the amount of the silver-based antibacterial and antiviral agent added was changed to 20.0 mass % of the solid content in the coating liquid.

[0064] Preparation of coating layer coating solution A photopolymerizable compound, pentaerythritol triacrylate (Viscoat #300, manufactured by Osaka Organic Chemical Industry Co., Ltd.) and a photopolymerization initiator (Omnirad184, manufactured by IGM Resins BV) were mixed in a weight ratio of photopolymerizable compound:photopolymerization initiator = 91:3, and toluene was added as a solvent so that the solid content concentration was 50 mass%. This mixture was thoroughly mixed using a magnetic stirrer to produce a coating layer coating liquid.

[0065] - Formation of antibacterial and antiviral layers and coating layers A biaxially stretched film made of polyethylene terephthalate (Cosmoshine A4260: manufactured by Toyobo Co., Ltd., thickness: 50 μm) cut into A4 size was used as the substrate. 1 mL to 2 mL of the antibacterial and antiviral layer coating liquid was dropped onto the substrate with a dropper, and the antibacterial and antiviral layer coating liquid was applied to the substrate with a #18 bar of a wireless bar coater (A-Bar: manufactured by Mitsui Electric Seiki Co., Ltd.). The coated film was dried for 1 minute in an atmospheric oven heated to 80°C to form an antibacterial and antiviral layer.

[0066] The laminate consisting of the substrate and the antibacterial and antiviral layer was left to stand in a thermostatic chamber at a temperature of 40° C. and a humidity of 20% RH for 96 hours to age the coating film. After aging, 1 mL to 2 mL of the coating liquid for the coating layer was dropped onto the upper surface of the antibacterial and antiviral layer using a dropper, and the coating liquid for the coating layer was applied to the antibacterial and antiviral layer using the #2 bar of a wireless bar coater (A-Bar: manufactured by Mitsui Electric Seiki Co., Ltd.). The coated film was dried at 100°C for 1 minute using a dryer, and then exposed to a high-pressure mercury UV device in a nitrogen atmosphere (oxygen concentration 500 ppm or less) with an integrated exposure of 200 mJ / cm. 2 The coating layer was formed by irradiating the coating with ultraviolet light so as to cure.

[0067] This resulted in the optical film of Example 4. In Example 4, the antibacterial and antiviral layer had a thickness of 1.0 μm, the coating layer had a thickness of 1.0 μm, and the content of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 20.0 mass%.

[0068] Example 5 Preparation of antibacterial and antiviral coating solution A photopolymerizable compound, pentaerythritol triacrylate (Osaka Organic Chemical Industry Co., Ltd.: Viscoat #300) and a photopolymerization initiator (IGM Resins BV: Omnirad184) were mixed in a weight ratio of photopolymerizable compound:photopolymerization initiator = 91:3. A silver-based antibacterial and antiviral agent (PTC-NTANV Additive ST: Dainichiseika Chemical Industry Co., Ltd., silver loading: 3 mass%, average particle size: 3 μm (volume-based median size)) was added to this mixture so that the ratio of the silver-based antibacterial and antiviral agent to the solid content in the coating liquid was 20.0 mass%. At this time, methyl isobutyl ketone was used as a solvent, and the solvent was added so that the solid content concentration in the coating liquid was 40.0 mass%, and the mixture was thoroughly mixed using a magnetic stirrer to produce an antibacterial and antiviral layer coating liquid. Preparation of coating layer coating solution Using the same materials and process as in Example 1, a coating solution for a covering layer was produced.

[0069] - Formation of antibacterial and antiviral layers and coating layers As the substrate, a triacetyl cellulose film (TJ40: manufactured by Fujifilm Corporation, thickness: 40 μm) cut to A4 size was used. 1 mL to 2 mL of the antibacterial and antiviral layer coating liquid was dropped onto the substrate with a dropper, and the antibacterial and antiviral layer coating liquid was applied to the substrate with a #10 bar of a wireless bar coater (A-Bar: manufactured by Mitsui Electric Seiki Co., Ltd.). The coated film was dried for 1 minute in an atmospheric oven heated to 100°C, and then exposed to a high-pressure mercury UV device in a nitrogen atmosphere (oxygen concentration 500 ppm or less) with an integrated exposure of 200 mJ / cm. 2 The coating was cured by irradiating with ultraviolet light so as to form an antibacterial and antiviral layer.

[0070] A coating layer was formed on the antibacterial and antiviral layer and aging was carried out by the same steps as in Example 1. This resulted in an optical film of Example 5. In Example 5, the antibacterial and antiviral layer had a thickness of 5.0 μm, the coating layer had a thickness of 1.0 μm, and the content of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 20.0 mass%.

[0071] Example 6 By using the same materials and processes as in Example 5, an antibacterial and antiviral layer coating solution was produced, and an antibacterial and antiviral layer was formed on a substrate that was a triacetyl cellulose film. Then, by using the same materials and processes as in Example 4, a coating layer coating solution was produced, and a coating layer was formed. Thereby, the optical film of Example 6 was obtained. In Example 6, the thickness of the antibacterial and antiviral layer was 5.0 μm, the thickness of the coating layer was 1.0 μm, and the content ratio of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 20.0% by mass.

[0072] (Comparative Example 1) An optical film of Comparative Example 1 was obtained by using the same materials and processes as in Example 1, except that the addition amount of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer coating solution was changed to 1.0% by mass of the solid content in the coating solution, and the coating layer was not formed. In Comparative Example 1, the thickness of the antibacterial and antiviral layer was 1.0 μm, and the content ratio of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 1.0% by mass.

[0073] (Comparative Example 2) An optical film of Comparative Example 2 was obtained by using the same materials and processes as in Example 1, except that the addition amount of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer coating solution was changed to 20.0% by mass of the solid content in the coating solution, and the coating layer was not formed. In Comparative Example 2, the thickness of the antibacterial and antiviral layer was 1.0 μm, and the content ratio of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 20.0% by mass.

[0074] (Comparative Example 3) An optical film of Comparative Example 3 was obtained by using the same materials and processes as in Example 5, except that the coating layer was not formed. In Comparative Example 3, the thickness of the antibacterial and antiviral layer was 5.0 μm, and the content ratio of the silver-based antibacterial and antiviral agent in the antibacterial and antiviral layer was 20.0% by mass.

[0075] (Evaluation Method) <Ag elution amount Ev> For the optical films of each of the examples and comparative examples, the amount of Ag elution Ev was calculated by the method described in the above embodiment. The amount of Ag ions was measured using a furnace-type atomic absorption spectrophotometer (ZA3700: manufactured by Hitachi High-Tech Science Corporation).

[0076] <Antibacterial> For the optical films of each Example and Comparative Example, antibacterial tests against Staphylococcus aureus and Escherichia coli were carried out in accordance with JIS Z 2801. As unprocessed samples, films from each Example and Comparative Example in which the addition of the antibacterial and antiviral agent was omitted were used. In the evaluation of antibacterial properties, a good "○" was given when the antibacterial activity value was 2.0 or more for both Staphylococcus aureus and Escherichia coli, and a poor "×" was given when the antibacterial activity value was less than 2.0 for at least one of Staphylococcus aureus and Escherichia coli.

[0077] <Antiviral> For the optical films of each Example and Comparative Example, antiviral tests against influenza A virus were carried out in accordance with ISO 21702. As unprocessed samples, films from each Example and Comparative Example in which the addition of the antibacterial and antiviral agent was omitted were used. In the evaluation of antiviral properties, an antiviral activity value of 2.0 or more was rated as good (○), and an antiviral activity value of less than 2.0 was rated as poor (×).

[0078] <Pencil hardness> For the optical films of each Example and Comparative Example, a hardness test was carried out using a pencil (uni: manufactured by Mitsubishi Pencil Co., Ltd.) and a Clemens scratch hardness tester (HA-301: manufactured by Tester Sangyo Co., Ltd.) under the conditions of a load of 500 g and a scratching speed of 0.5 mm / sec to measure the pencil hardness of the optical film surface. In the measurement, the test was repeated while changing the pencil hardness, and the surface of the optical film was visually observed, and the maximum hardness at which no scratches were observed was taken as the measurement result.

[0079] <Scratch resistance> The optical films of each of the Examples and Comparative Examples were placed in a Gakushin-type friction fastness tester (AB-301, manufactured by Tester Sangyo Co., Ltd.), and steel wool (Bonstar #0000, manufactured by Nippon Steel Wool Co., Ltd.) was applied to the surface of the optical film at a rate of 500 g / cm. 2 A scratch resistance test was conducted by contacting the optical film with the tape at a pressure of 0.01 mm and moving it back and forth 10 times. After the test, the surface of the optical film was visually observed to check for the presence or absence of scratches. In the evaluation of scratch resistance, a good score of "○" was given when no scratches were observed, a fair score of "△" was given when 1 to 9 scratches were observed, and a poor score of "×" was given when 10 or more scratches were observed.

[0080] <Anti-stain properties> For the optical films of each of the Examples and Comparative Examples, the antifouling properties were evaluated by evaluating the removability of fingerprints by wiping them off in the following manner.

[0081] (1) The back surface of the optical film was attached to a blackboard with an optical adhesive, and artificial leather with olive oil applied was pressed against the surface of the optical film to apply olive oil to the surface of the optical film.

[0082] (2) The olive oil adhering to the surface of the optical film was wiped off with tissue paper (Scottie: manufactured by Nippon Paper Kracie Co., Ltd.) under a load of 1 kg, and then the reflectance spectroscopy measurement of the surface of the optical film was performed. The above-mentioned wiping off of the olive oil and the reflectance spectroscopy measurement were then repeated. The reflectance spectroscopy measurement was also performed before the olive oil was attached.

[0083] (3) Color difference ΔE between before and after olive oil is applied to the surface of the optical film * ab is calculated based on the results of reflectance spectroscopy, and the color difference ΔE *The number of times of wiping when ab became 0.5 or less was defined as the number of times of wiping complete. Based on the number of times of wiping complete, the fingerprint wiping property was evaluated. In the evaluation of the fingerprint wiping property, i.e., the evaluation of the stain resistance, when the number of times of wiping complete was less than 5 times, it was rated as particularly good "◎", when the number of times of wiping complete was 5 times or more but less than 10 times, it was rated as good "○", when the number of times of wiping complete was 10 times or more but less than 30 times, it was rated as somewhat good "△", and when the number of times of wiping complete was 30 times or more, it was rated as poor "×".

[0084] <Slipperiness> The dynamic friction coefficient of the surface of the optical film of each of the Examples and Comparative Examples was measured under the following conditions in accordance with JIS K 7125. Measurement device: Static and dynamic friction measuring device (TL201Tt: manufactured by Trinity Labs) Probe: Tactile contactor with fingerprint pattern (with fingerprint pattern proposed by Takashi Maeno Laboratory, Graduate School of System Design and Management, Keio University, and Misao Nomura Laboratory, Graduate School of Science and Technology, Yamagata University) Analysis software: Tribo analysis software ·Vertical load: 20g -Sliding speed: 10mm / sec ·Traveling distance: 30mm Data collection speed: 1msec

[0085] In the measurement, the optical film, the back side of which was attached to a blackboard with an adhesive, was fixed to the stage of the measuring device, and the friction coefficient between the tactile contactor with the fingerprint pattern and the surface of the optical film was measured according to the above conditions.Then, the average value of the friction coefficient in the sliding state, that is, the friction coefficient when the moving distance was 10 mm or more and 20 mm or less, was calculated, and the obtained value was taken as the kinetic friction coefficient μk.

[0086] In the evaluation of slipperiness, a dynamic friction coefficient μk of 0.3 or less was rated as good (○), a dynamic friction coefficient μk of more than 0.3 and less than 0.5 was rated as fair (△), and a dynamic friction coefficient μk of more than 0.5 was rated as poor (×).

[0087] The fingerprint pattern tactile contactor has a hardness equivalent to that of a finger and an uneven pattern like an actual fingerprint, allowing measurements to be made under conditions close to that of an actual finger. The smaller the dynamic friction coefficient, the easier it is for a finger to slide on the surface of the optical film, meaning that the feel is good.

[0088] <Haze> The haze of the optical films of each of the Examples and Comparative Examples was measured using a haze meter (NDH7000: manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7136.

[0089] <Anti-reflection> The reflectance of the surface of the optical film of each Example and Comparative Example was measured as the spectral reflectance at an incident angle of 5°. An automatic spectrophotometer (U-4100: manufactured by Hitachi, Ltd.) was used to measure the reflectance. The measurement was performed after anti-reflection treatment was performed by applying a matte black paint to the back surface of the optical film. In the evaluation of antireflection properties, a reflectance of less than 1% was rated as good (◯), and a reflectance of 1% or more was rated as poor (×). <Pure water contact angle>

[0090] The contact angle of pure water was measured on the surface of the optical film of each example and each comparative example. A contact angle meter (LSE-ME4: manufactured by NIC Co., Ltd.) was used to measure the contact angle. The amount of the pure water droplet during measurement was about 1 μL, and the state was measured 5 seconds after the droplet landed.

[0091] Table 1 shows the configurations of the antibacterial and antiviral layer and the coating layer for each of the examples and comparative examples, as well as the evaluation results obtained by the above-mentioned evaluation methods.

[0092] [Table 1]

[0093] As shown in Table 1, the Ag elution amount Ev is 20 ng / cm 2In the above-mentioned Examples 1 to 6, both the antibacterial property and the antiviral property are good. 2 In Comparative Example 1, where the Ag elution amount Ev is less than 20 ng / cm, the antibacterial property is good but the antiviral property is insufficient. 2 It was confirmed that if the above conditions were met, antiviral properties could be satisfactorily obtained in addition to antibacterial properties.

[0094] In Comparative Example 1, which does not have a coating layer, the pencil hardness, scratch resistance, and slipperiness are insufficient. Furthermore, in Comparative Example 2, in which the proportion of the antibacterial and antiviral agent is increased to increase the amount of Ag elution Ev, antiviral properties are obtained, but the pencil hardness, scratch resistance, slipperiness, and antifouling properties are insufficient. Therefore, it is suggested that, in the absence of a coating layer, the more the proportion of the antibacterial and antiviral agent is increased, the more difficult it is to obtain properties other than antibacterial and antiviral properties. In Comparative Example 3, in which the type of resin was changed to increase the thickness from Comparative Example 2, the pencil hardness, scratch resistance, and slipperiness were improved, but the antifouling properties were insufficient. Therefore, it is suggested that it is difficult to obtain various properties well only by improving the antibacterial and antiviral layer.

[0095] In contrast, Examples 1 to 6, which have a coating layer, have better pencil hardness, scratch resistance, and slipperiness than Comparative Examples 1 and 2, and also have better stain resistance than Comparative Examples 2 and 3. Furthermore, when comparing Examples 5 and 6 and Comparative Example 3, which have the same antibacterial and antiviral layer configuration, Examples 5 and 6 have better scratch resistance and stain resistance.

[0096] Therefore, the coating layer is provided and the Ag elution amount Ev is 20 ng / cm 2It was confirmed that the above conditions make it possible to simultaneously achieve antibacterial and antiviral properties, pencil hardness, scratch resistance, antifouling properties, and slipperiness. In addition, it was confirmed that the degree of freedom in the material of the coating layer is high, since each property is obtained well regardless of whether the material of the coating layer is a thermosetting resin or an ultraviolet curing resin. It was also confirmed that each property is obtained well regardless of whether the resin constituting the antibacterial and antiviral layer is a thermosetting resin or an ultraviolet curing resin, and further regardless of the combination of the types of resins of the antibacterial and antiviral layer and the coating layer.

[0097] Furthermore, the haze is 10% or less in Examples 1, 2, and 4. The magnitude of the haze can be adjusted by the thickness of the coating layer, the average particle size and content of the antibacterial and antiviral agent, the presence or absence of materials or fine particles in the antibacterial and antiviral layer or coating layer, the average particle size and content of the fine particles, etc.

[0098] In addition, in Examples 1 to 6, the antireflection properties are all poor, but the antireflection properties can be improved by including fine particles in the antibacterial and antiviral layer or the coating layer, including a refractive index adjuster in the coating layer, etc. When the optical film is used for an application that does not require a reduction in reflectance, even if the antireflection properties are poor, it is not unsuitable as an optical film. The optical properties including haze and antireflection properties may be adjusted according to the application of the optical film, and if the optical film has a coating layer, such optical properties can be easily adjusted.

[0099] In addition, in Examples 1 to 5, the pure water contact angle is 75° or more. The pure water contact angle can be adjusted by the material of the coating layer. For example, the pure water contact angle can be increased by including a fluorine compound in the coating layer or using a fluorine polymer as the resin component of the coating layer.

[0100] As mentioned above, the Ag elution amount Ev is 20 ng / cm 2As long as the above is satisfied, the material of the coating layer is not limited, and it is possible to improve a specific property among the pencil hardness, scratch resistance, antifouling property, and slipperiness, in addition to the pure water contact angle, by adjusting the material of the coating layer. Therefore, it is possible to easily control the properties according to the application of the optical film.

[0101] As described above, according to the above-described embodiment and examples, the following effects can be obtained. (1) Since the antibacterial and antiviral layer 21 is covered with the coating layer 22, the decrease in properties other than the antibacterial and antiviral properties due to the inclusion of the silver-based antibacterial and antiviral agent is compensated for by the coating layer 22. Furthermore, when the amount of Ag elution Ev is 20 ng / cm 2 For the above reasons, sufficient antibacterial and antiviral properties can be obtained even if the antibacterial and antiviral layer 21 is covered with the coating layer 22. Therefore, it is possible to achieve both antibacterial and antiviral properties and other properties.

[0102] (2) If the antibacterial and antiviral layer 21 contains fine particles in addition to a silver-based antibacterial and antiviral agent, it is possible to adjust the light scattering properties of the optical film 10. This makes it possible to control the haze and antireflection properties of the optical film.

[0103] (3) The resin components of the antibacterial and antiviral layer 21 and the coating layer 22 are thermosetting or ultraviolet-curing resins, making it easy to form these layers and to obtain the materials for them. If the resin components of the antibacterial and antiviral layer 21 and the coating layer 22 are both ultraviolet-curing resins, the adhesion between the antibacterial and antiviral layer 21 and the coating layer 22 is improved, and the versatility of the optical film 10 is increased. [Explanation of symbols]

[0104] Pm…functional particle 10...Optical film 20...Base material 21...Antibacterial and antiviral layer 22…Covering layer

Claims

1. A substrate; an antibacterial and antiviral layer supported on the substrate; a covering layer covering the antibacterial and antiviral layer on a side opposite to the substrate with respect to the antibacterial and antiviral layer, the antibacterial and antiviral layer contains a resin component and a silver-based antibacterial and antiviral agent, The coating layer contains a resin component, The surface of the coating layer opposite to the antibacterial and antiviral layer is the surface of the optical film, and when the surface is in contact with pure water for 24 hours, the amount of Ag ions eluted per unit area of ​​the surface is 20 ng / cm ２ That's all. Optical film.

2. The antibacterial and antiviral layer contains fine particles in addition to the silver-based antibacterial and antiviral agent. The optical film according to claim 1 .

3. The resin component contained in the antibacterial and antiviral layer is either a thermosetting resin or an ultraviolet curing resin. The optical film according to claim 1 .

4. The resin component contained in the coating layer is either a thermosetting resin or an ultraviolet curing resin. The optical film according to claim 1 .

5. The resin component contained in the antibacterial and antiviral layer and the resin component contained in the coating layer are each an ultraviolet curable resin. The optical film according to claim 1 .

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