Production method for resin film, and metal casting mold

Abstract

Provided is a production method for a resin film having a roughened shape on at least part of a surface of the resin film, said method comprising a transferring step for bringing a metal casting mold that has a roughened surface on at least a part of a surface thereof into contact with a resin film, thereby transferring the roughened shape of the roughened surface to the resin film, wherein the roughened surface of the metal casting mold has a root mean square slope (Sdq) of 0.14-0.99 and a developed area ratio (Sdr) of 0.094-0.4285 as measured in accordance with ISO 25178.

Description

Resin film manufacturing method and metal mold

[0001] The present invention relates to a method for producing a resin film and a metal mold.

[0002] Resin films are required to have many properties depending on their applications, and for example, resin films with high water repellency and hydrophilicity have a wide range of applications. In addition, in recent years, in order to prevent infection with COVID-19, the so-called novel coronavirus disease, and seasonal influenza, resin films that people touch with their hands are sometimes required to have antiviral properties on their surfaces.

[0003] Patent Document 1 listed below describes an antiviral surface treatment method that imparts antiviral properties to the surface of a component by performing a projection process (hereinafter also referred to as a "blast process") in which shot material is projected onto the surface of the component to randomly form countless minute irregularities having a specific irregularity pitch width and recess depth width.

[0004] JP 2022-28394 A

[0005] One criterion for evaluating antiviral properties is the "antiviral activity value," and with the technology described in Patent Document 1, the comparative object (stainless steel plate material) does not exhibit antiviral properties, but when subjected to an antiviral surface treatment method, the antiviral activity value is 0.4 to 0.7 after 24 hours at 25° C. However, as a result of studies by the present inventors, it was found that the antiviral properties obtained with the technology described in Patent Document 1 are insufficient, because blasting involves a projection process in which shot material is projected onto the surface of the component, and therefore only a convex shape can be imparted to the component's back surface.

[0006] Incidentally, Patent Document 1 neither describes nor suggests imparting water repellency or hydrophilicity to the resin film.

[0007] In view of the above, an object of the present invention is to provide a method for producing a resin film that can impart water repellency, hydrophilicity, and / or antiviral properties to a resin film by imparting a roughened shape to at least a portion of the surface of the resin film.A further object of the present invention is to provide a metal mold for forming a roughened shape on at least a portion of the surface of a resin film, the metal mold being capable of imparting water repellency, hydrophilicity, and / or antiviral properties to a resin film by imparting a roughened shape to at least a portion of the surface of the resin film.

[0008] The above-mentioned problems can be solved by the following configuration: The present invention relates to a method for producing a resin film having a roughened shape on at least a portion of its surface, which includes a transfer step of contacting a metal mold having a roughened surface on at least a portion of its surface with the resin film to transfer the roughened shape of the roughened surface to the resin film, wherein the roughened surface of the metal mold has a developed area ratio (Sdr) of 0.005 to 0.5 and a root-mean-square slope (Sdq) of 0.1 to 1.5, as measured in accordance with ISO 25178.

[0009] In the above-mentioned method (1) for producing a resin film, a method (2) for producing a resin film is preferred in which water repellency is imparted to at least a part of the surface of the resin film in the transfer step.

[0010] In the above-mentioned method (2) for producing a resin film, a method (3) for producing a resin film is preferred, in which the resin film has a contact angle with water of 90° or more before the transfer step.

[0011] In the above-mentioned method (1) for producing a resin film, a method (4) for producing a resin film is preferred, in which hydrophilicity is imparted to at least a part of the surface of the resin film in the transfer step.

[0012] In the method (4) for producing a resin film, a method (5) for producing a resin film is preferred, in which the resin film has a contact angle with water of 90° or less before the transfer step.

[0013] In the above-mentioned method for producing a resin film (1), a method for producing a resin film (6) is preferred, in which antiviral properties are imparted to at least a part of the surface of the resin film in the transfer step.

[0014] The present invention also relates to a metal mold (7) for forming a roughened shape on at least a portion of the surface of a resin film, the metal mold having a roughened surface on at least a portion of its surface for transferring the roughened shape to the resin film, the roughened surface having a developed area ratio (Sdr) of 0.005 to 0.5 and a root-mean-square slope (Sdq) of 0.1 to 1.5, as measured in accordance with ISO 25178.

[0015] The method for producing a resin film according to the present invention includes a transfer step in which a metal mold having a roughened surface on at least a portion of its surface is brought into contact with a resin film to transfer the roughened surface's texture to the resin film. In the method for producing a resin film according to the present invention, the roughened surface of the metal mold is designed so that the developed area ratio (Sdr) measured in accordance with ISO 25178 is 0.005 to 0.5 and the root-mean-square slope (Sdq) is 0.1 to 1.5. This allows the resin film to be imparted with water repellency, hydrophilicity, and / or antiviral properties.

[0016]

[0017] The method for producing a resin film according to the present invention produces a resin film that exhibits water repellency, hydrophilicity, and / or antiviral properties by having a roughened shape on at least a portion of its surface. The method for producing a resin film according to the present invention includes a transfer step in which a metal mold having a roughened surface on at least a portion of its surface is brought into contact with the resin film to transfer the roughened shape of the roughened surface to the resin film. The roughened surface of the metal mold used in the transfer step has a developed area ratio (Sdr) of 0.005 to 0.5 and a root-mean-square slope (Sdq) of 0.1 to 1.5, as measured in accordance with ISO 25178.

[0018] In the resin film manufacturing method according to the present invention, various resin films can be used as raw materials to advantageously impart the desired water repellency, hydrophilicity, and / or antiviral properties. For example, when imparting water repellency to at least a portion of the surface of the resin film, it is preferable to use a resin film having a contact angle with water of 90° or more as the raw material, and an example of such a resin film is polypropylene (PP) film. Furthermore, when imparting hydrophilicity to at least a portion of the surface of the resin film, it is preferable to use a resin film having a contact angle with water of 90° or less as the raw material, and an example of such a resin film is poly(meth)acrylic film.

[0019] Furthermore, for example, when imparting antiviral properties to at least a portion of the surface of a resin film, examples of resin films that can be used as raw materials include thermoplastic resins, thermosetting resins, and UV-curable resins. Examples of thermoplastic resins include general-purpose plastics such as polypropylene, polyacrylic resins, and ABS resins; engineering plastics such as nylon 6, nylon 66, polyacetal, polycarbonate, polybutylene terephthalate, and modified polyphenylene ether; and super engineering plastics such as polyphenylene ether, liquid crystal polymers, and polyetherimides. Examples of thermosetting resins include phenolic resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, polyurethane resins, diallyl phthalate resins, silicone resins, and alkyd resins. Examples of UV-curable resins include acrylic resins and epoxy resins.

[0020] Next, the metal mold used in the transfer process will be described.

[0021] The metal mold used in the transfer step of the resin film manufacturing method according to the present invention has a roughened surface on at least a portion of its surface. Specific properties of the roughened surface will be described separately. Examples of metal members constituting the metal mold include aluminum, aluminum alloys, copper, copper alloys, nickel, nickel alloys, stainless steel, titanium, titanium alloys, iron, and iron alloys. Among these, in the present invention, it is preferable to use aluminum, aluminum alloys, copper, or copper alloys as the metal member, and it is more preferable to use copper or copper alloys. The shape and size of the metal mold can be appropriately designed depending on the application of the resin film to be imparted with water repellency, hydrophilicity, and / or antiviral properties.

[0022] An example of a process for forming a roughened surface on at least a part or all of the surface of a metal mold is a roughening treatment process in which a microetching agent is brought into contact with the surface of a metal member to form a roughened surface on the surface of the metal member.

[0023] As the microetching agent used in the roughening treatment step, for example, an organic acid microetching agent, an inorganic acid microetching agent, an alkaline microetching agent, or a hydrogen peroxide microetching agent can be used.

[0024] Examples of organic acid-based microetching agents include microetching agents made of an aqueous solution containing an organic acid, a metal ion source, a halide ion source, and the like.

[0025] Examples of inorganic acid microetching agents include microetching agents made of an acidic aqueous solution containing an inorganic acid, a metal ion source, a halide ion source, and the like.

[0026] Examples of alkaline microetching agents include microetching agents made of an aqueous solution containing an alkali source, an amphoteric metal ion source, nitrate ions, a thio compound, and the like.

[0027] Examples of hydrogen peroxide-based microetching agents include microetching agents made of an aqueous solution containing hydrogen peroxide and sulfuric acid as the main components.

[0028] The roughening treatment step may be carried out in one step, but in order to obtain more preferable properties of the roughened surface of the metal mold to be produced, it is preferably carried out in two steps, and it is particularly preferably carried out in three steps: a pretreatment step, a main treatment step, and a post-treatment step. An embodiment in which the roughening treatment step is carried out in three steps will be described below.

[0029] The pretreatment step may include, for example, immersing at least the surface of the metal member to be treated in an alkaline soft etching agent such as a hydrogen peroxide-based soft etching agent consisting of an aqueous solution mainly containing diluted nitric acid, hydrogen peroxide, and sulfuric acid, or an aqueous solution containing the above-mentioned alkali source, an amphoteric metal ion source, nitrate ions, a thio compound, etc. The treatment temperature may be, for example, 15 to 40°C, and the treatment time may be, for example, about 3 seconds to 10 minutes.

[0030] This treatment step may involve immersing at least the treatment surface of the metal member in the organic acid microetchant, inorganic acid microetchant, alkaline microetchant, or hydrogen peroxide microetchant, etc. The treatment temperature may be, for example, 10 to 40°C, and the treatment time may be, for example, about 5 seconds to 10 minutes.

[0031] The post-treatment step may include immersing at least the treated surface of the metal member in diluted nitric acid, etc. The treatment temperature may be, for example, 15 to 40° C., and the treatment time may be, for example, about 3 to 40 seconds.

[0032] After the roughening treatment step, a roughened surface can be formed on the surface of the metal member, having a developed area ratio (Sdr) of 0.005 to 0.5 and a root-mean-square slope (Sdq) of 0.1 to 1.5, as measured in accordance with ISO 25178. The developed area ratio (Sdr) and root-mean-square slope (Sdq) of the roughened surface formed on the surface of the metal member can be adjusted by changing the type of microetchant used in the roughening treatment step, as well as the treatment time and / or temperature of the roughening treatment step (one step, two steps, and / or three steps). In order to impart a higher level of water repellency, hydrophilicity, and / or antiviral properties to the resin film, it is more preferable that the roughened surface of the metal mold have a developed area ratio (Sdr) of 0.0094 to 0.4285 and a root-mean-square slope (Sdq) of 0.14 to 0.99, as measured in accordance with ISO 25178.

[0033] Next, the transfer step of the resin film manufacturing method according to the present invention will be described. In the transfer step, a metal mold having a roughened surface on at least a part of its surface is brought into contact with the resin film, thereby transferring the roughened shape of the roughened surface to the resin film.

[0034] A method for transferring the roughened surface of the metal mold to the resin film by contacting the metal mold with the resin film includes, for example, overlapping the roughened surface of the metal mold with the surface of the resin film to be subjected to water-repellent treatment, hydrophilic treatment, and / or antiviral treatment, and heat pressing using a press. On the other hand, a method for transferring the roughened surface of the metal mold surface to the surface of a thermosetting resin or UV-curable resin includes, for example, forming a mold including at least the roughened surface of the metal mold, pouring the raw material components of the thermosetting resin or UV-curable resin into it, curing it, and then demolding the resin film, thereby transferring the roughened surface formed on the surface of the metal member to the surface of the thermosetting resin or UV-curable resin.

[0035] After the transfer step, a complex roughened shape is formed on the surface of the resin film. Specific examples of the complex roughened shape formed on the surface of the resin member after the transfer step will be described later.

[0036] The resin film manufacturing method according to the present invention can impart water repellency, hydrophilicity, and / or antiviral properties to the resin film. In the present invention, the water repellency of the resin film is evaluated by its contact angle with water. Specifically, in the present invention, water repellency is considered to have been imparted when the contact angle is 10° or more higher than the contact angle of the untreated resin film before the transfer process. In the present invention, a resin film having a contact angle with water of more than 110° is produced, and such a resin film is particularly preferred because it has excellent water repellency. Furthermore, in the present invention, the water repellency of the resin film is also evaluated by its contact angle with water. When the contact angle is 10° or more lower than the contact angle of the untreated resin film before the transfer process, water repellency is considered to have been imparted. In the present invention, a resin film having a contact angle with water of 70° or less is produced, and such a resin film is particularly preferred because it has excellent hydrophilicity.

[0037] Furthermore, the resin film manufacturing method according to the present invention can manufacture a resin film with excellent antiviral properties, and the antiviral activity value, which indicates the degree of antiviral properties, can be calculated by the following formula with reference to JIS R1756:2020 (visible light responsive photocatalyst, antiviral, film adhesion method). Ｄ = Log(B Ｄ ) -Log(C Ｄ ) (1) In the above formula (1), V Ｄ indicates the antiviral activity value, D indicates the dark place, B indicates the infectivity value of the unprocessed product, and C indicates the infectivity value of the processed product.

[0038] As described above, the resin film manufacturing method according to the present invention can manufacture a resin film with excellent antiviral properties. Therefore, the resin film manufacturing method according to the present invention is also useful as a treatment method for imparting antiviral properties to resin films used in home appliances, housing building materials / equipment, toilet-related facilities / supplies, kitchen-related facilities / supplies, bathroom-related facilities / supplies, office equipment / supplies, printing (printed materials, laminated products, and paper), transportation equipment, industrial equipment / industrial supplies (films, packaging materials / films for food, etc., packaging materials), medical care / nursing / health, communication-related / accessories, pet supplies, daily necessities (shoes, cleaning supplies, cosmetics, etc.), etc.

[0039] An example of an embodiment of the present invention will be described below, but the present invention is not limited to this description in any way.

[0040] <Method for measuring the developed area ratio (Sdr) and root-mean-square slope (Sdq) of the roughened surface of a metal mold> Using a confocal microscope manufactured by Lasertec (Hybrid Laser Microscope OPTELICS HYBRID+), the developed area ratio (Sdr) and root-mean-square slope (Sdq) of the roughened surface of a metal mold were measured in accordance with ISO 25178. Note that, during the measurement, an S filter (0.0025 mm) and an L filter (0.08 mm) were used to set a cutoff value.

[0041] [Example of manufacturing a metal mold (example of forming a roughened surface)] First, a (untreated) copper plate without a roughened shape was prepared. FIG. 1 shows a scanning electron microscope photograph (magnification 1500 times) of the surface of a (untreated) copper plate without a roughened shape, and FIG. 2 shows a scanning electron microscope photograph (magnification 5000 times) of the surface of a (untreated) copper plate without a roughened shape. By subjecting the untreated copper plate to a roughening treatment process, at least a part of the surface was subjected to a metal mold A having a roughened surface with a roughened shape A, a metal mold B having a roughened surface with a roughened shape B, a metal mold C having a roughened surface with a roughened shape C, and a metal mold D having a roughened surface with a roughened shape D were produced. FIG. 3 is a scanning electron micrograph (magnification: 1500x) of the surface of a copper plate (metal mold A) having a roughened shape A, FIG. 4 is a scanning electron micrograph (magnification: 5000x) of the surface of a copper plate (metal mold A) having a roughened shape A, FIG. 5 is a scanning electron micrograph (magnification: 1500x) of the surface of a copper plate (metal mold B) having a roughened shape B, FIG. 6 is a scanning electron micrograph (magnification: 5000x) of the surface of a copper plate (metal mold B) having a roughened shape B, and FIG. 7 is a scanning electron micrograph (magnification: 1500x) of the surface of a copper plate (metal mold B) having a roughened shape B. FIG. 8 shows a scanning electron microscope photograph (magnification 1500x) of the surface of the copper plate (metal mold C) having roughened shape C, FIG. 9 shows a scanning electron microscope photograph (magnification 1500x) of the surface of the copper plate (metal mold D) having roughened shape D, and FIG. 10 shows a scanning electron microscope photograph (magnification 5000x) of the surface of the copper plate (metal mold D) having roughened shape D. The details of the roughening treatment process performed on metal mold A, metal mold B, metal mold C, and metal mold D are described below.

[0042] [Roughening Treatment Process for Metal Mold A] A roughening treatment process (three steps: pretreatment step, main treatment step, and post-treatment step) was carried out on an unused copper plate (100 mm x 100 mm x 1.3 mm thick) under the following conditions. The conditions for each step are shown below. (Pretreatment Step) The surface of the copper plate to be treated was sprayed with a sulfuric acid / hydrogen peroxide-based soft etching agent. Treatment temperature: 25°C. Treatment time: 20 seconds. (Main Treatment Step) Following the pretreatment, the surface of the copper plate to be treated was sprayed with an inorganic acid-based microetching agent (a microetching agent consisting of an aqueous solution containing an inorganic acid, a metal ion source, a halide ion source, etc.). Treatment temperature: 30°C. Treatment time: 50 seconds. (Post-Treatment Step) Following the main treatment, the surface of the copper plate to be treated was sprayed with dilute hydrochloric acid. Treatment temperature: 25°C. Treatment time: 15 seconds. Table 1 shows the developed area ratio (Sdr) and root mean square slope (Sdq) of the roughened surface of the metal mold A obtained after the roughening treatment step.

[0043] [Roughening Treatment Step for Metal Mold B] A roughening treatment step (three steps: pretreatment step, main treatment step, and post-treatment step) was performed on an unused copper plate (100 mm × 100 mm × 1.3 mm thick) under the following conditions. The conditions for each step are shown below. (Pretreatment Step) The surface of the copper plate to be treated was sprayed with a sulfuric acid / hydrogen peroxide-based soft etching agent. Treatment temperature: 25°C. Treatment time: 20 seconds. (Main Treatment Step) Following the pretreatment, the surface of the copper plate to be treated was sprayed with an inorganic acid-based microetching agent (a microetching agent consisting of an aqueous solution containing an inorganic acid, a metal ion source, a halide ion source, etc.). Treatment temperature: 30°C. Treatment time: 50 seconds. (Post-Treatment Step) Following the main treatment, the surface of the copper plate to be treated was sprayed with dilute hydrochloric acid. Treatment temperature: 25°C. Treatment time: 15 seconds. The developed area ratio (Sdr) and root mean square slope (Sdq) of the roughened surface of the metal mold B obtained after the roughening treatment step are shown in Table 1.

[0044] [Roughening Treatment Process for Metal Mold C] A roughening treatment process (three steps: pretreatment step, main treatment step, and post-treatment step) was carried out on an unused copper plate (100 mm x 100 mm x 1.3 mm thick) under the following conditions. The conditions for each step are shown below. (Main Treatment Step) Following the pretreatment, the surface of the copper plate to be treated was sprayed with a sulfuric acid / hydrogen peroxide-based microetchant. Treatment temperature: 30°C. Treatment time: 50 seconds. The developed area ratio (Sdr) and root mean square slope (Sdq) of the roughened surface of the metal mold C obtained after the roughening treatment process are shown in Table 1.

[0045] [Roughening Treatment Process for Metal Mold D] A roughening treatment process (three steps: pretreatment step, main treatment step, and post-treatment step) was carried out on an unused copper plate (100 mm x 100 mm x 1.3 mm thick) under the following conditions. The conditions for each step are shown below. (Pretreatment Step) The surface of the copper plate to be treated was sprayed with a sulfuric acid / hydrogen peroxide-based soft etching agent. Treatment temperature: 25°C. Treatment time: 20 seconds. (Main Treatment Step) Following the pretreatment, the surface of the copper plate to be treated was sprayed with an organic acid-based microetching agent (a microetching agent consisting of an aqueous solution containing an organic acid, a metal ion source, a halide ion source, etc.). Treatment temperature: 30°C. Treatment time: 50 seconds. (Post-Treatment Step) Following the main treatment, the surface of the copper plate to be treated was sprayed with dilute hydrochloric acid. Treatment temperature: 25°C. Treatment time: 15 seconds. The developed area ratio (Sdr) and root mean square slope (Sdq) of the roughened surface of the metal mold D obtained after the roughening treatment step are shown in Table 1.

[0046]

[0047] <Method for measuring the contact angle of a resin film with water> The contact angle of a resin film with water was measured under the following conditions: Measuring instrument: Kyowa Interface Science automatic contact angle meter (DM-501) Measurement conditions: Measurement solvent: DI water Measurement method: Contact angle immediately after droplet deposition Liquid volume: 2.0 μL Analysis method: Sessile drop method, θ / 2 method

[0048] [Resin Film Transfer Process (Providing Water Repellency)] A polypropylene film (PP film) was prepared as the resin film. The contact angle of the untreated PP film before the transfer process was 96°. The transfer process was carried out on the untreated PP film using the following method. The roughened surfaces of the metal molds A, B, C, and D were superimposed on the surface of the untreated polypropylene film (PP film) before the transfer process to be subjected to water repellency treatment, and the roughened shapes of the metal molds A, B, C, and D were transferred to the untreated polypropylene film (PP film) by heat pressing using a press. Table 4 shows the heat pressing conditions.

[0049] Example 1 A resin film (PP film) according to Example 1 was produced by carrying out the transfer process using metal mold A. FIG. 11 shows a scanning electron microscope photograph (magnification 1500x) of the surface of the resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold A) having a roughened shape A, and FIG. 12 shows a scanning electron microscope photograph (magnification 5000x) of the surface of the resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold A) having a roughened shape A. The contact angle of the resin film (PP film) obtained after the transfer process was 116 °, indicating high water repellency.

[0050] Example 2 A resin film (PP film) according to Example 2 was produced by carrying out the transfer process using metal mold B. FIG. 13 shows a scanning electron microscope photograph (magnification 1500x) of the surface of the resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold B) having a roughened shape B, and FIG. 14 shows a scanning electron microscope photograph (magnification 5000x) of the surface of the resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold B) having a roughened shape B. The contact angle of the resin film (PP film) obtained after the transfer process was 118 °, indicating high water repellency.

[0051] Example 3 A resin film (PP film) according to Example 3 was produced by carrying out the transfer process using a metal mold C. FIG. 15 shows a scanning electron microscope photograph (magnification 1500x) of the surface of a resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold C) having a roughened shape C, and FIG. 16 shows a scanning electron microscope photograph (magnification 5000x) of the surface of a resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold C) having a roughened shape C. The contact angle of the resin film (PP film) obtained after the transfer process was 124 °, indicating high water repellency.

[0052] Example 4 A resin film (PP film) according to Example 4 was produced by carrying out the transfer process using metal mold D. FIG. 17 shows a scanning electron microscope photograph (magnification 1500x) of the surface of a resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold D) having a roughened shape D, and FIG. 18 shows a scanning electron microscope photograph (magnification 5000x) of the surface of a resin film (PP film) in which the transfer process was carried out using a copper plate (metal mold A) having a roughened shape D. The contact angle of the resin film (PP film) obtained after the transfer process was a contact angle of more than 140 °, indicating high water repellency.

[0053] Table 2 shows the contact angle of the untreated PP film before the transfer process (Comparative Example 1) and the contact angle of the PP film after the transfer process in Examples 1 to 4. In all of Examples 1 to 4, the contact angle of the PP film was increased by 10° or more, indicating that excellent water repellency was imparted.

[0054]

[0055] [Resin Film Transfer Process (Hydrophilicity Impartation)] A poly(meth)acrylic film (Acryl film) was prepared as the resin film. The contact angle of the untreated Acryl film before the transfer process was 84°. The transfer process was carried out on the untreated Acryl film using the following method. Acryl raw material components were poured onto the roughened surfaces of metal molds A, B, C, and D, and after UV curing, the resin film was demolded to produce films onto which the roughened shapes of metal molds A, B, C, and D were transferred. Table 4 shows the heat press conditions.

[0056] Example 5 A resin film (Acryl film) according to Example 5 was produced by carrying out the transfer process using metal mold A. FIG. 19 shows a scanning electron microscope photograph (magnification 1500x) of the surface of a resin film (Acryl film) subjected to the transfer process using a copper plate (metal mold A) having roughened shape A, and FIG. 20 shows a scanning electron microscope photograph (magnification 5000x) of the surface of a resin film (Acryl film) subjected to the transfer process using a copper plate (metal mold A) having roughened shape A. The contact angle of the resin film (Acryl film) obtained after the transfer process was 65°, indicating high hydrophilicity.

[0057] Example 6 A resin film (Acryl film) according to Example 6 was produced by carrying out the transfer process using metal mold B. FIG. 21 shows a scanning electron microscope photograph (magnification 1500x) of the surface of a resin film (Acryl film) in which the transfer process was carried out using a copper plate (metal mold B) having roughened shape B, and FIG. 22 shows a scanning electron microscope photograph (magnification 5000x) of the surface of a resin film (Acryl film) in which the transfer process was carried out using a copper plate (metal mold B) having roughened shape B. The contact angle of the resin film (Acryl film) obtained after the transfer process was 46°, indicating high hydrophilicity.

[0058] Table 3 shows the contact angle of the untreated Acryl film before the transfer process (Comparative Example 2) and the contact angle of the Acryl film after the transfer process in Examples 5 and 6. In all of Examples 5 and 6, the contact angle of the Acryl film was reduced by 10° or more, indicating that excellent hydrophilicity was imparted.

[0059]

[0060] [Resin Film Transfer Process (Imparting Antiviral Properties)] The roughened surfaces of the metal molds A, B, C, and D were superimposed on the antiviral-treated surfaces of untreated resin films (polypropylene film (PP film) and poly(meth)acrylic film (Acryl film)) before the transfer process, and the surfaces were heat-pressed using a press to transfer the roughened shapes of the metal molds A, B, C, and D to the untreated resin films (polypropylene film (PP film) and poly(meth)acrylic film (Acryl film)). Table 4 shows the heat-pressing conditions.

[0061]

[0062] Examples 7 to 8: The resin films (PP films) of Examples 7 and 8 were produced by carrying out the transfer process using the metal mold B. Example 9: The resin film (PP film) of Example 9 was produced by carrying out the transfer process using the metal mold C. Examples 10 to 11: The resin films (PP films) of Examples 10 and 11 were produced by carrying out the transfer process using the metal mold D.

[0063] Examples 12 to 13: The resin films (Acryl films) according to Examples 12 to 13 were produced by carrying out the transfer process using the metal mold A. Examples 14 to 15: The resin films (Acryl films) according to Examples 14 to 15 were produced by carrying out the transfer process using the metal mold B. Examples 16 to 17: The resin films (Acryl films) according to Examples 16 to 17 were produced by carrying out the transfer process using the metal mold C. Example 18: The resin film (Acryl film) according to Example 18 was produced by carrying out the transfer process using the metal mold D.

[0064] <Evaluation of Antiviral Properties> Using Ref. (-) (glass plate) as an unprocessed product, the antiviral properties of the resin films (polypropylene film (PP film) and poly(meth)acrylic film (Acryl film)) produced in Examples 7 to 18 were evaluated under the following conditions. [Test Standard] JIS R1756:2020 (visible light responsive photocatalyst, antiviral, film adhesion method) was referenced. [Name of Unprocessed Product] Ref. (-) (glass plate) [Test item name] Resin films (polypropylene film (PP film) and poly(meth)acrylic film (Acryl film)) produced in Examples 7 to 18 [Test item (PP film and Acryl film) size] 50 mm x 50 mm x t≦1 mm [Number of test items] n=1 [Test phages] Bacteriophage Qβ (NBRC 20012) [host Escherichia coli (NBRC 106373)]; the results are shown in Tables 5 and 7. Bacteriophage φ6 (NBRC 105899, not specified in JIS) [host Pseudomonas syringae (NBRC 14084)]; the results are shown in Tables 6 and 8. [Test phage dilution] 1 / 500NB [Sterilization of test sample] Sterilization with UV 254 nm (15 minutes on each side) [Action conditions] Temperature 25°C, dark place, action time 0 hours, 8 hours [Adhesive film] Polypropylene film (VF-10, KOKUYO), 40 mm x 40 mm

[0065]

[0066] As shown in Table 5, the PP films obtained in Examples 7, 9, and 10 showed a significant decrease in infectivity titer against bacteriophage Qβ (a norovirus surrogate) after 8 hours at 25°C in the dark. Similarly, the antiviral activity value also increased after 8 hours at 25°C in the dark. From these results, it can be seen that the PP films subjected to the transfer process using metal template B, metal template C, and metal template D exhibit a remarkable antiviral effect due to the formation of a very complex roughened shape on the surface of the PP film.

[0067]

[0068] As shown in Table 6, the PP films obtained in Examples 8 and 11 also showed a significant decrease in infectivity titer against bacteriophage φ6 (influenza virus, COVID-19 surrogate) after 8 hours at 25°C in the dark. Accordingly, the antiviral activity value also increased after 8 hours at 25°C in the dark. These results demonstrate that the PP films subjected to the transfer process using metal mold B and metal mold D exhibit a remarkable antiviral effect due to the formation of a very complex roughened shape on the surface of the PP film.

[0069]

[0070] As shown in Table 7, the Acryl films obtained in Examples 12, 14, and 16 showed a significant decrease in infectivity titer against bacteriophage Qβ (a norovirus surrogate) after 8 hours at 25°C in the dark. Similarly, the antiviral activity value also increased after 8 hours at 25°C in the dark. These results demonstrate that the Acryl films subjected to the transfer process using metal template A, metal template B, and metal template C exhibit a significant antiviral effect due to the formation of a very complex roughened shape on the surface of the Acryl film.

[0071]

[0072] As shown in Table 8, the Acryl films obtained in Examples 13, 15, 17, and 18 showed a significant decrease in infectivity titer against bacteriophage φ6 (influenza virus, COVID-19 surrogate) after 8 hours at 25°C in the dark. Accordingly, the antiviral activity value also increased after 8 hours at 25°C in the dark. These results demonstrate that the Acryl films subjected to the transfer process using metal template A, metal template B, metal template C, and metal template D exhibit a remarkable antiviral effect due to the formation of a very complex roughened shape on the surface of the Acryl film.

Claims

1. A method for manufacturing a resin film having a roughened shape on at least a part of its surface, the method comprising a transfer step of bringing a metal mold having a roughened surface into contact with the resin film to transfer the roughened shape of the roughened surface to the resin film, wherein the roughened surface of the metal mold has a developed area ratio (Sdr) measured in accordance with ISO 25178 of 0.005 to 0.5 and a root mean square slope (Sdq) of 0.1 to 1.

5.

2. The method for manufacturing a resin film according to claim 1, wherein in the transfer step, water repellency is imparted to at least a part of the surface of the resin film.

3. The method for manufacturing a resin film according to claim 2, wherein the contact angle of the resin film with water before the transfer step is 90° or more.

4. The method for manufacturing a resin film according to claim 1, wherein in the transfer step, hydrophilicity is imparted to at least a part of the surface of the resin film.

5. The method for manufacturing a resin film according to claim 4, wherein the contact angle of the resin film with water before the transfer step is 90° or less.

6. The method for manufacturing a resin film according to claim 1, wherein in the transfer step, antiviral property is imparted to at least a part of the surface of the resin film.

7. A metal mold for forming a roughened shape on at least a part of the surface of a resin film, the metal mold having a roughened surface for transferring the roughened shape to the resin film on at least a part of its surface, wherein the roughened surface has a developed area ratio (Sdr) measured in accordance with ISO 25178 of 0.005 to 0.5 and a root mean square slope (Sdq) of 0.1 to 1.5.

Images