Transparent film

Abstract

For example, it can be used for clear curtains, awnings, tents, etc. that are placed near windows or entrances in stores or homes, and can provide a multifunctional transparent film that has weather resistance and antiviral activity while maintaining transparency. [Solution] A transparent film (10) includes a transparent base sheet (20), a first surface protective layer (30) laminated on one of the front and back surfaces of the base sheet (20) and having an embossed portion (31), and a second surface protective layer (40) laminated on the other of the front and back surfaces of the base sheet (20) and having no embossed portion, wherein a weathering agent is added to at least one of the base sheet (20) and the first surface protective layer (30) or the second surface protective layer (40), and an antiviral agent is added to the first surface protective layer (30) and the second surface protective layer (40), the amount of the antiviral agent added is 4 to 10 parts by mass per 100 parts by mass of the solid content of the surface protective layers (30, 40), and there are multiple peaks in the particle size distribution of the antiviral agent.

Description

[Technical Field]

[0001] The present invention can provide a multifunctional transparent film that can be used, for example, for clear curtains, awnings, tents, etc. that are installed near windows or entrances in stores or homes, and that has weather resistance and antiviral properties while maintaining transparency. [Background technology]

[0002] The COVID-19 pandemic has increased demand for antiviral properties, making the development of antiviral products urgent. As the use of open clothing increases, there is demand for partitions such as curtains that are weather-resistant and heat-blocking. Also, from a security standpoint, transparent or semi-transparent curtains are in demand. Conventionally, decorative boards have been known that have antibacterial, antiviral, and other effects and that can reduce the impact on the design of the decorative board (see paragraph

[0009] and FIG. 1 of Patent Document 1). Furthermore, conventionally, a curtain that is transparent and has a protrusion on one surface is known (see paragraphs

[0011] and

[0012] and FIG. 2 of Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-27694 [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-131048 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional decorative board (Patent Document 1) is not transparent, and the antiviral effect is limited to the surface of the decorative board, making it unsuitable for curtains and the like. Furthermore, the above-mentioned conventional curtain (Patent Document 2) is transparent but does not have antiviral properties. In view of the various problems described above, the present invention provides a transparent film that has weather resistance and antiviral properties while maintaining transparency. [Means for solving the problem]

[0005] A transparent film according to one aspect of the present invention includes a transparent base sheet, a first surface protective layer laminated on one of the front and back surfaces of the base sheet and having an embossed portion formed thereon, and a second surface protective layer laminated on the other of the front and back surfaces of the base sheet and having no embossed portion formed thereon, wherein a weathering agent is added to at least one of the base sheet and the first and second surface protective layers, and an antiviral agent is added to the first and second surface protective layers, and the amount of the antiviral agent added is 4 to 10 parts by mass per 100 parts by mass of the solids content of the surface protective layer.

[0006] In a transparent film according to one aspect of the present invention, the depth of the embossed portion is 150 μm or less. A transparent film according to one aspect of the present invention is characterized in that the depth of the embossed portion gradually decreases from the center of the embossed portion in the width direction toward the edges of the embossed portion.

[0007] In the transparent film according to one aspect of the present invention, the first surface protective layer and the second surface protective layer each have a thickness of 3 to 15 μm. A transparent film according to one aspect of the present invention is characterized in that the relationship represented by the following formula (1) holds when the average particle size of the antiviral agent is "φ" and the thickness of the outermost surface protective layer is "D". 0.5D≦φ≦2D...Formula (1) A transparent film according to one aspect of the present invention is characterized in that the antiviral agent has a particle size distribution with multiple peaks. [Effects of the Invention]

[0008] According to one aspect of the present invention, a multifunctional transparent film can be provided that has weather resistance and antiviral properties while maintaining transparency. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a transparent film according to a first embodiment. [Figure 2] FIG. 10 is a cross-sectional view of a transparent film according to a second embodiment. [Figure 3] FIG. 10 is a cross-sectional view of a transparent film according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Embodiment 1) First to third embodiments of the present invention will be described below with reference to FIGS. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, shapes, structures, etc. of the components as described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0011] (Transparent film 10 according to embodiment 1) In FIG. 1, 10 denotes a transparent film, and although not shown, the transparent film 10 is used for clear curtains, awnings, tents, etc. that are placed near windows or entrances in stores or homes. As shown in FIG. 1, the transparent film 10 is formed by laminating the following three layers. The following (1) to (3) will be explained later. (1) Base sheet 20 (2) First surface protection layer 30 (3) Second surface protective layer 40 Although the transparent film 10 is exemplified by (1) to (3) above, it is not limited to these, and a printed layer 50 may be provided between the base sheet 20 and the second surface protective layer 40, as will be described later with reference to Figure 2.

[0012] (Main features of Transparent Film 10) The transparent film 10 according to the first embodiment has the following features. (1) A transparent film (10) formed from a transparent base sheet (20), a first surface protective layer (30) laminated on one of the front and back surfaces of the base sheet (20) and having an embossed portion (31), and a second surface protective layer (40) laminated on the other of the front and back surfaces of the base sheet (20) and having no embossed portion, wherein a weathering agent is added to at least one of the base sheet (20) and the first surface protective layer (30) and the second surface protective layer (40), and an antiviral agent is added to the first surface protective layer (30) and the second surface protective layer (40), and the amount of the antiviral agent added is 4 to 10 parts by mass per 100 parts by mass of the solid content of the surface protective layers (30, 40). According to the transparent film 10 described above, it is possible to provide a multifunctional transparent film 10 that has weather resistance and antiviral properties on both sides of the base sheet 20 while maintaining transparency. Furthermore, since the transparent film 10 has the embossed portion 31 on only one side thereof, the transparent film 10 gives different impressions when viewed from the front and back sides, improving the design. If the amount of antiviral agent added is less than 4 parts by mass, the effect is not exhibited and the antiviral activity value tends to decrease significantly, whereas if it exceeds 10 parts by mass, weather resistance tends to decrease.

[0013] (2) The depth of the embossed portion 31 is 150 μm or less. The transparent film 10 described above can maintain weather resistance. That is, if the depth exceeds 150 μm and is too deep, there is a risk that discoloration, whitening, cracks, etc. may occur in the sheet after the weather resistance test.

[0014] (3) The depth of the embossed portion (for example, the second embossed portion 32) gradually decreases from the center portion of the embossed portion 32 in the width direction toward the ends. It is believed that the shallower the depth of the embossed portion 32, the more advantageous it is in terms of antiviral properties. On the other hand, if the depth of the embossed portion 32 is shallower, the height difference decreases, and the embossing effect is reduced. For this reason, the embossed portion 32 is formed so that it gradually becomes shallower from the center portion in the width direction toward the ends, and by changing the depth of the embossed portion 32, it is possible to achieve both antiviral properties and embossing effects.

[0015] (4) The thickness of the first surface protection layer 30 and the second surface protection layer 40 is 3 to 15 μm. If the thickness of the transparent film 10 is less than 3 μm, the film is too thin, and the content of other weather-resistant agents and the like is relatively reduced, which may result in a decrease in weather resistance. Furthermore, if the thickness exceeds 15 μm, it is too thick and there is a risk that the antiviral activity value will be significantly reduced.

[0016] (5) When the average particle size of the antiviral agent is "φ" and the thickness of the surface protection layers 30, 40 is "D", the relationship of the following formula (1) holds. 0.5D≦φ≦2D...Formula (1) When the relationship of the above formula (1) is satisfied, the antiviral effect, i.e., antiviral properties, can be improved by increasing the contact area with the antiviral agent and the surface area of ​​the antiviral agent itself. Furthermore, in terms of the relationship between thickness and particle size, the effect is more likely to be exhibited if a certain amount of the antiviral agent is exposed on the surface.

[0017] (6) There are multiple peaks in the particle size distribution of the antiviral agent. The transparent film 10 described above not only increases the packing density of the antiviral agent, but also increases the contact area with the antiviral agent, thereby increasing the surface area of ​​the antiviral agent itself and improving the antiviral properties. In order to expose silver ions on the surface, it is advantageous for the particle size to be large to some extent. In order to facilitate the generation of silver ions, it is desirable to have a small particle size and a large surface area, and both effects can be achieved.

[0018] (Base sheet 20) The substrate sheet 20 serves as a support for the transparent film 10 of the present invention, and is in the form of a transparent sheet or film. The base sheet 20 is made of a polyvinyl chloride (PVC) sheet. Although polyvinyl chloride has been exemplified as the material of the base sheet 20, the material is not limited to this, and other transparent films may also be used. The base sheet 20 may be made of, for example, ethylene vinyl alcohol (EVA), polypropylene (PP), polyethylene terephthalate (PET), or polyethylene (PE). The thickness of the base sheet 20 is, for example, 200 to 600 μm. If it is too thin, it will be difficult to process and will be less durable, while if it is too thick, problems will arise in terms of weight, visibility, and processability. For example, the base sheet 20 is a 300 μm PVC sheet (manufactured by Tatsuno Chemical Co., Ltd.). Transparency includes translucency, and the target transmittance is 50% or more in the wavelength range of 400 to 800 nm.

[0019] (First surface protection layer 30) The first surface protection layer 30 is laminated on one of the front and back surfaces of the base sheet 20, is transparent, and has an embossed portion 31 formed thereon. The first surface protective layer 30, like the second surface protective layer 40 described below, is mainly composed of an acrylic resin composition containing, for example, methacrylate as a monomer component. Although an acrylic resin composition is used as the first surface protection layer 30, the present invention is not limited to this. A weather resistant agent may be added to the first surface protective layer 30 to improve weather resistance, similar to the base sheet 20. The same applies to the second surface protective layer 40 described below. In addition, the first surface protective layer 30 contains an antiviral agent, as in the base sheet 20, which will be described later.

[0020] (Embossed part 31) The embossed portion 31 is formed on the surface of the first surface protection layer 30, and can improve the texture and design. The embossed portion 31 is formed on the surface of the first surface protection layer 30 and has, for example, a rectangular cross section. The embossed portion 31 was formed by embossing to a depth of 150 μm, for example. If the depth exceeds 150 μm and is too deep, discoloration, whitening, cracks, etc. may occur in the sheet after the weather resistance test. Although the shape of the embossed portion 31 is exemplified as a rectangular cross section, it is not limited to this, and may be formed to have a V-shaped cross section, as will be described later with reference to FIG.

[0021] (Second surface protective layer 40) The second surface protection layer 40 is laminated on the other side of the front and back surfaces of the base sheet 20 and has transparency. The second surface protection layer 40 is formed in the same manner as the first surface protection layer 30 except that the embossed portion 31 is not present.

[0022] (weatherproofing agent) A weathering agent is added to the first surface protective layer 30 and the second surface protective layer 40 (hereinafter also referred to as "surface protective layers 30, 40") in order to improve the weather resistance of the transparent film 10. Although the weatherproofing agent is added to the surface protective layers 30 and 40, it is not limited to this, and may be attached to the base sheet 20 or both. Weatherproofing agents include, for example, triazines and benzotriazines, and include, for example, ultraviolet absorbers (UVA) and light stabilizers (HALS). Ultraviolet absorbers (UVA) include benzotriazoles, benzoates, benzophenones, triazines, salicylates, and cyanoacrylates. Light stabilizers (HALS) include hindered amines. As the weatherproofing agent, the above-mentioned agents are generally added in any combination depending on the application. By adding a weather resistant agent to the surface protective layers 30, 40, the effect of preventing discoloration and cracking was obtained when a weather resistance test was carried out for 10 cycles using a metal weather tester, as will be described later.

[0023] (Amount of weatherproofing agent added) The amount of the weather resistant agent added is, for example, 0.5 to 30 parts by mass. If the amount is less than 0.5 parts by mass, weather resistance will decrease, and if it exceeds 30 parts by mass, the content of other antiviral agents will decrease relatively, which may result in a decrease in antiviral properties. When the weather resistant agent is added to both the base sheet 20 and the surface protective layers 30, 40, the amounts added may be the same or different. At this time, it is desirable that the amount of weather resistant agent added is fixed at 1 part for the base sheet 20 and 10 parts for the surface protective layers 30, 40. Furthermore, when the weathering agent is added to both the first surface protective layer 30 and the second surface protective layer 40, the amounts added may be the same or different.

[0024] (Matting agent addition) A matting agent may be added to the surface protective layers 30 and 40 . By adding a matting agent, the gloss of the surface of the surface protection layers 30, 40 can be adjusted. Examples of matting agents include inorganic fine particles such as silica, calcium carbonate, synthetic mica, titanium oxide, and glass particles; and organic fine particles such as polyethylene fine particles, acrylic resin fine particles, urethane resin fine particles, urea resin fine particles, nylon resin fine particles, and balloons. Although the case where the matting agent is applied to the surface protective layers 30 and 40 has been exemplified, the present invention is not limited to this, and the matting agent may be applied to the base sheet 20 or to both.

[0025] (Antiviral agent) The antiviral agent is inorganic, and among these, silver is used as the main component. The silver component is supported on an inorganic material. Here, "glass" is used as the "inorganic material", but the "inorganic material" is not limited to "glass". By supporting the silver component with an inorganic substance, the durability of the antiviral effect can be improved. As the silver-based antiviral agent, for example, TB-B100 (manufactured by Taisho Technos) was used, and 4 parts by mass of the agent was added to the solid content and applied. Although TB-B100 (manufactured by Taisho Technos) has been exemplified as an antiviral agent, the present invention is not limited to this, and antiviral agents (PTC-NT ANV Additive (ST)) and (PTC-NT ANV Additive (ST)) manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. may also be used.

[0026] (Antiviral agent added amount) The amount of antiviral agent added is 4 parts by mass as exemplified above, but is not limited to this, and is preferably 4 to 10 parts by mass per 100 parts by mass of the solid content of the surface protection layers 30, 40. If the amount is less than 4 parts by mass, the effect is not exhibited and the antiviral activity value tends to be significantly reduced, whereas if the amount is more than 10 parts by mass, the weather resistance tends to be reduced.

[0027] (Thickness of antiviral agent) The thickness of the antiviral agent is preferably, for example, 3 μm to 15 μm. If the thickness is less than 3 μm, the film is too thin and does not exhibit any effect, and the antiviral activity value tends to decrease significantly. Furthermore, if the thickness exceeds 15 μm, the thickness is too thick, and the content of other weather-resistant agents etc. is relatively reduced, so that the weather resistance tends to decrease.

[0028] (Characteristics of antiviral agents) The antiviral agent has the following characteristics: (1) The particle size distribution of the antiviral agent has multiple peaks. According to the above-described features, in addition to the effect of increasing the packing density of the antiviral agent, the contact area with the antiviral agent is expanded, which enables the surface area of ​​the antiviral agent itself to be increased, thereby improving the antiviral properties. In order to expose silver ions on the surface, it is advantageous for the particle size to be large to some extent. In order to facilitate the generation of silver ions, it is desirable to have a small particle size and a large surface area, and both effects can be achieved. As the multiple peaks, it is preferable to have two peaks, one between 1 and 5 μm and the other between 5 and 10 μm.

[0029] (2) The average particle size of the antiviral agent is within the range of 1 to 10 μm. When the average particle size of the antiviral agent is 1 μm or more, the contact area between surface protective layer 80 and the antiviral agent is increased, resulting in better antiviral properties. When the average particle size of the antiviral agent is 10 μm or less, scratch resistance is better than when the average particle size exceeds 10 μm.

[0030] (3) When the average particle size of the antiviral agent is "φ" and the thickness of the surface protective layers 30, 40 is "D", the relationship "0.5D≦φ≦2D... Equation (1)" holds. When the relationship of the above formula (1) is satisfied, the antiviral effect, i.e., antiviral properties, can be improved by increasing the contact area with the antiviral agent and the surface area of ​​the antiviral agent itself. Furthermore, in terms of the relationship between thickness and particle size, the effect is more likely to be exhibited if a certain amount of the antiviral agent is exposed on the surface.

[0031] (4) In the system in which the antiviral agent is added to the surface protective layers 30 and 40, a surfactant is further added. The surfactant may be cationic, amphoteric or nonionic, and may be used alone or in combination of two or more types. Adding a surfactant improves the compatibility between the antiviral agent and the binder of the surface protective layers 30, 40, and can suppress concentration variations due to precipitation of the antiviral agent during coating.

[0032] (Manufacturing method) The transparent film 10 has the above-described configuration, and its manufacturing method includes the following steps. (1) First step The first step is a step of laminating a first surface protective layer 30 on one of the front and back surfaces of a transparent substrate sheet 20, and laminating a second surface protective layer 40 on the other surface. The base sheet 20 is a vinyl chloride sheet, for example, a 300 μm PVC sheet (manufactured by Tatsuno Chemical Co., Ltd.).

[0033] The surface protection layers 30 and 40 are made of an acrylic resin composition containing, for example, methacrylate as a monomer component as the main component, to which a silver-based antiviral agent is added, and are applied to the front and back surfaces of the base sheet 20, respectively. For example, TB-B100 (manufactured by Taisho Technos) was used as the antiviral agent, and was added in an amount of, for example, 4 parts by mass relative to the solid content. (2)Second process The second step is a step of forming embossed portions 31 on the surface of the first surface protection layer 30. By carrying out the second step, the transparent film 10 can be obtained.

[0034] (Explanation of the second embodiment shown in FIG. 2) The second embodiment will be described with reference to FIG. In the second embodiment, firstly, a printed layer 50 is formed between the base sheet 20 and the second surface protective layer 40, and the transparent film 10 has four layers. The print layer 50 is a layer for decorating the surface of the transparent film 10 . The printed layer 50 is formed by printing a pattern, illustration, or the like on the other surface of the base sheet 20 facing the second surface protective layer 40, and a coating of printing ink is used. The design may be chosen at will depending on the intended use and the user's preferences, and common designs include wood grain, stone grain, and abstract patterns. Printing ink is made primarily from, for example, acrylic resin. Since a transparent sheet is used as the base sheet 20, the pattern of the printing layer 50 can be seen through the base sheet 20 from the surface side of the first surface protection layer 30 having the embossed portion 31.

[0035] (Synchronization of the pattern on the printing layer 50 and the embossed portion 31) Secondly, in the second embodiment, the shape of the embossed portion 31 is made to match the design of the print layer 50. Here, "synchronization" means that the pattern on the printing layer 50 and the shape of the embossed portion 31 are patterns formed by the outline in a plan view and are characterized by matching at a rate of 50% or more.

[0036] (Anchor layer) In addition, an anchor layer (not shown) may be provided in association with the printing layer 50. The anchor layer is a layer formed so as to cover the entire surface of the base sheet 20, and is a layer for preventing powder falling off of the inorganic material contained in the transparent film 10. When printing the print layer 50 on the base sheet 20, if the inorganic material contained in the transparent film 10 falls off in the printing system, specifically in the printing device, it may contaminate the printing system.

[0037] (Description of the third embodiment shown in FIG. 3) The third embodiment will be described with reference to FIG. The present embodiment 3 shows a modified example of the embossed portion 31 of the embodiment 1 shown in FIG. 1, and as shown in FIG. 3, the second embossed portion 32 is formed so that it gradually becomes shallower from the center of the second embossed portion 32 toward the ends in the width direction. The second embossed portion 32 is formed, for example, in a V-shaped cross section. By forming the second embossed portion 32 in a V-shaped cross section, the depth of the second embossed portion 32 can be changed. It is believed that the shallower the depth of the second embossed portion 32, the more advantageous it is in terms of antiviral properties. On the other hand, if the depth of the second embossed portion 32 is shallower, the height difference decreases, and the embossing effect is reduced. For this reason, the second embossed portion 32 is formed to have a V-shaped cross section and the depth is varied, thereby achieving both antiviral properties and an embossing effect. Although a V-shape has been exemplified as the cross-sectional shape of the second embossed portion 32, this is not limited to this, and it is sufficient that the second embossed portion 32 is gradually shallower from the center of the width direction toward the ends, and although not shown, it may also be recessed into a polygonal shape such as a semicircular cross section or a trapezoidal cross section with a slope.

[0038] (Other features of Transparent Film 10) Other features of the transparent film 10 according to the first embodiment are as follows. (1) The printed layer 50 is formed between the base sheet 20 and the second surface protective layer 40 , and the embossed portion 31 is in harmony with the design of the printed layer 50 . According to the transparent film 10 described above, the printed layer 50 can improve the design of the transparent film 10, and by harmonizing the design of the printed layer 50 with the embossed portion 31, the design can be further improved. Although the embossed portion 31 is synchronized with the pattern of the print layer 50, the present invention is not limited to this, and the embossed portion 31 does not have to be synchronized.

[0039] (2) The method includes a first step of laminating a first surface protective layer 30 on either the front or back surface of a transparent base sheet 20 and a second surface protective layer 40 on the other surface of the base sheet 20, and a second step of forming an embossed portion 31 on the surface of the first surface protective layer 30. A weather resistant agent is added to at least one of the base sheet 20 and the first and second surface protective layers 30 and 40, and an antiviral agent is added to the first and second surface protective layers 30 and 40. The amount of the antiviral agent added is 4 to 10 parts by mass relative to 100 parts by mass of the solid content of the surface protective layers 30 and 40. According to the above-described method for manufacturing the transparent film 10, it is possible to produce a multifunctional transparent film 10 that maintains transparency while imparting weather resistance and antiviral properties to both sides of the base sheet 20. The first and second steps may be reversed, and the embossed portion 31 may be formed before the first and second surface protective layers 30 and 40 are laminated. [Example]

[0040] The decorative sheet according to the present invention will be explained below with reference to Examples 1 to 5 and Comparative Examples 1 to 10. However, the present invention is not limited to Examples 1 to 5 below.

[0041] Example 1 The main configuration of Example 1 is as shown in Table 1 below. In addition, in Table 1 below, the main configurations of Examples 2 to 5 and Comparative Examples 1 to 10 in addition to Example 1 are also entered. [Table 1]

[0042] In Example 1, a 300 μm PVC sheet (manufactured by Tatsuno Chemical Industry Co., Ltd.) was used as the base sheet 20 . A silver-based antiviral agent, TB-B100 (manufactured by Taisho Technos), was added in an amount of 4 parts by mass relative to the solid content and applied to the substrate sheet 20 to form the surface protective layers 30 and 40. In addition, an embossed portion 31 having a depth of 150 μm was processed, and the transparent film 10 of Example 1 was produced. The surface protection layers 30 and 40 have a thickness of 10 μm. The weather resistance agent is added only to the surface protective layers 30 and 40, and the amount added is 10 parts by mass.

[0043] Example 2 In Example 2, the amount of antiviral agent added was 10 parts by mass relative to the solid content, the thickness of the base sheet 20 was 200 μm, the thickness of the surface protective layers 30, 40 was 3 μm, and 10 parts by mass of the weather resistant agent was added only to the base sheet 20. The other conditions were the same as in Example 1, and a transparent film 10 of Example 2 was produced.

[0044] Example 3 In Example 3, the depth of the embossed portion 31 was processed to 100 μm, the thickness of the base sheet 20 was 600 μm, the thickness of the surface protective layers 30, 40 was 15 μm, and 10 parts by mass of weathering agent was added to both the base sheet 20 and the surface protective layers 30, 40.The rest was the same as in Example 1, and a transparent film 10 of Example 3 was produced.

[0045] Example 4 In Example 4, 0.5 parts by mass of a weather resistant agent was added only to the surface protective layers 30 and 40, and the other conditions were the same as in Example 1, and a transparent film 10 of Example 4 was produced. Example 5 In Example 5, 30 parts by mass of a weather resistant agent was added only to the surface protective layers 30 and 40, and the other conditions were the same as in Example 1, and a transparent film 10 of Example 5 was produced.

[0046] (Comparative Example 1) In Comparative Example 1, the antiviral agent was added in an amount of 3 parts by mass relative to the solid content, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 1 was produced. (Comparative Example 2) In Comparative Example 2, the antiviral agent was added in an amount of 11 parts by mass relative to the solid content, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 2 was produced.

[0047] (Comparative Example 3) In Comparative Example 3, the embossed portions 31 were processed to a depth of 160 μm, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 3 was produced. Comparative Example 4 In Comparative Example 4, the thickness of the substrate sheet 20 was set to 100 μm, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 4 was produced.

[0048] (Comparative Example 5) In Comparative Example 5, the thickness of the substrate sheet 20 was set to 700 μm, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 5 was produced. (Comparative Example 6) In Comparative Example 6, the thickness of the surface protective layers 30, 40 was set to 2 μm, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 6 was produced.

[0049] (Comparative Example 7) In Comparative Example 7, the thickness of the surface protective layers 30, 40 was set to 16 μm, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 7 was produced. (Comparative Example 8) In Comparative Example 8, a transparent film 10 was produced in the same manner as in Example 1, except that no weathering agent was added to either the base sheet 20 or the surface protective layers 30, 40.

[0050] (Comparative Example 9) In Comparative Example 9, the weathering agent was added only to the surface protective layers 30 and 40 to a thickness of 0.4 μm, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 8 was produced. (Comparative Example 10) In Comparative Example 10, the weathering agent was added only to the surface protective layers 30 and 40 to a thickness of 31 μm, and the other conditions were the same as in Example 1, and a transparent film 10 of Comparative Example 10 was produced.

[0051] (Evaluation criteria) The transparent films 10 of Examples 1 to 5 and Comparative Examples 1 to 10 obtained as described above were subjected to the following performance evaluations (1) to (4). (1) Antiviral activity Antiviral activity was measured by the Braak method (based on ISO 21702), with activity values ​​of 2 or more marked as "Good" and values ​​below 2 marked as "Poor." The virus used was an enveloped type (influenza virus).

[0052] (2) Weather resistance Weather resistance was evaluated as "good" when no discoloration, whitening, or cracking occurred after the weather resistance test, and evaluated as "poor" when one or more of discoloration, whitening, and cracking occurred. The weather resistance test was carried out under the following conditions using a metal weather tester (KU-R5DCI-A) manufactured by Daipla Wintes Co., Ltd. The black panel temperature was 53°C, and the illuminance was 65 mW / cm2 (20 hours of UV irradiation + 4 hours of condensation) as one cycle, and 10 cycles were performed.

[0053] (3) Transparency Regarding transparency, a transmittance of 50% or more in the wavelength region of 400 to 800 nm was evaluated as "good," and a transmittance of less than 50% was evaluated as "poor." The transmittance was measured and evaluated using an ultraviolet-visible spectrophotometer. (4) Processability The processability was evaluated comprehensively mainly from the viewpoints of durability, workability taking weight into consideration, and visibility. If there were no problems with durability, workability, or visibility, the evaluation was given as "○", and if not, the evaluation was given as "×".

[0054] (Evaluation results) The results are shown in Table 2. [Table 2]

[0055] (Examples 1 to 5 and Comparative Examples 1 to 10) Among Examples 1 to 5 and Comparative Examples 1 to 10, Examples 1 to 5 received a "good" mark in all performance evaluation items, making them "passed." In contrast, Comparative Examples 1 to 10 had one or more "x" marks in the performance evaluation items, and all were "failed."

[0056] (Antiviral activity) Comparative Examples 1 and 6 failed in terms of antiviral activity. In Comparative Example 1, the amount of antiviral agent added was "3 parts by mass," which is presumably too small. In Comparative Example 6, the thickness of the surface protection layers 30 and 40 was "2 μm", which is presumably too thin. As a result, it can be inferred that the amount of antiviral agent added must exceed "3 parts by mass" and the thickness of the surface protection layers 30, 40 must exceed "2 μm."

[0057] (About weather resistance) Regarding weather resistance, Comparative Examples 2, 3, and 7 to 9 failed. In Comparative Example 2, the amount of antiviral agent added was "11 parts by mass," which is presumably too much. As a result, it can be inferred that the amount of antiviral agent added needs to be less than "11 parts by mass." In Comparative Example 3, the depth of the embossed portion 31 was "160 μm", which is presumably too deep. As a result, it can be inferred that the depth of the embossed portion 31 needs to be less than "160 μm."

[0058] In Comparative Example 7, the thickness of the surface protection layers 30 and 40 was "16 μm", which is presumably too thick. As a result, it can be inferred that the thickness needs to be less than 16 μm. It is presumed that the reason for this in Comparative Example 8 is that no weathering agent was added to either the base sheet 20 or the surface protective layers 30, 40. In Comparative Example 9, the amount of weathering agent added was "0.4 μm" only in the surface protective layers 30 and 40, which is presumably too little. As a result, it can be inferred that the amount of weathering agent added must exceed "0.4 μm."

[0059] (Regarding transparency) All of Comparative Examples 1 to 10 passed the test for transparency. (Regarding processability) With regard to processability, Comparative Examples 4, 5 and 10 failed. In Comparative Example 4, the thickness of the base sheet 20 was "100 μm", which is presumably because it was too thin. In Comparative Example 5, the thickness of the base sheet 20 was "700 μm", which is presumably too thick. As a result, it can be inferred that the thickness of the base sheet 20 needs to be more than "100 μm" and less than "700 μm." In Comparative Example 10, the amount of weathering agent added was "31 μm" for only the surface protective layers 30 and 40, which is presumably too much. As a result, it can be inferred that the amount of weathering agent added must be less than "31 μm." [Explanation of symbols]

[0060] 10 transparency film 20 Base sheet 30 First surface protective layer 31 Embossed section 32 Second embossed section 40 Second surface protective layer 50 printing layers

Claims

1. A transparent film comprising: a transparent base sheet; a first surface protective layer laminated on one of the front and back surfaces of the base sheet and having an embossed portion; and a second surface protective layer laminated on the other of the front and back surfaces of the base sheet and having no embossed portion, a weather resistant agent is added to at least one of the base sheet, the first surface protective layer, and the second surface protective layer; an antiviral agent is added to the first surface protective layer and the second surface protective layer; the amount of the antiviral agent added is 4 to 10 parts by mass per 100 parts by mass of the solid content of the surface protective layer, the antiviral agent has a particle size distribution with multiple peaks, The depth of the embossed portion is 150 μm or less, The thickness of the base sheet is 200 to 600 μm, the first surface protective layer and the second surface protective layer each contain an acrylic resin as a resin component, the first surface protective layer and the second surface protective layer each have a thickness of 3 to 15 μm; a transparent film characterized in that the amount of each weathering agent added in the first surface protective layer and the second surface protective layer is 0.5 to 30 parts by mass relative to 100 parts by mass of the solid content of each of the first surface protective layer and the second surface protective layer.

2. 2. The transparent film according to claim 1, wherein the peaks are two peaks between 1 and 5 μm and between 5 and 10 μm.

3. the transparent film is located between the base sheet and the second surface protective layer and includes a printing layer on which a picture is printed, 3. The transparent film according to claim 1, wherein the embossed portion of the first surface protective layer is in harmony with the pattern of the printed layer.

4. 4. The transparent film according to claim 1, wherein the depth of the embossed portion gradually decreases from the center of the embossed portion toward the ends in the width direction of the embossed portion.

Images