Layered article including synthetic polymer film having antimicrobial and / or antiviral properties, and method for producing the same

Abstract

To provide a method for producing a laminate comprising a synthetic polymer film having antimicrobial and / or antiviral properties.SOLUTION: A method for producing a layered article including a synthetic polymer film having antimicrobial and / or antiviral properties comprises: preparing a layered article 50A having a substrate 42 and a synthetic polymer film 34A formed on the substrate, in which the synthetic polymer film has, on a surface thereof, a plurality of protrusions 34Ap having an area equivalent circle diameter in a range of more than 20 nm to less than 500 nm when viewed from a normal direction of the synthetic polymer film; and irradiating the plurality of protrusions in the layered article with light emitted from a xenon lamp such that an amount of irradiation with light in a wavelength range of 300 nm or more to 400 nm or less is 6 MJ / m2 or more.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to a laminate including a synthetic polymer film having antibacterial and / or antiviral properties, and a method for producing the same.

Background Art

[0002] The applicant of the present application has disclosed, for example, in Patent Documents 1 to 4, a synthetic polymer film having a moth-eye structure on the surface and a surface having a bactericidal action. The term "synthetic polymer film" is used to distinguish it from natural products (lipid membranes) such as mica and dragonfly wings having a nano surface structure. All of the disclosure contents of Patent Documents 1 to 4 are incorporated herein by reference.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to further improve the bactericidal action of a synthetic polymer film. Here, the object is to improve antibacterial properties evaluated by a method conforming to the JIS Z2801 standard and / or antiviral properties evaluated by a method conforming to ISO 21702:2019.

Means for Solving the Problems

[0005] According to an embodiment of the present invention, the solution means described in the following items are provided. [Item 1] A method for manufacturing a laminate comprising a synthetic polymer film having antibacterial and / or antiviral properties, comprising a substrate and a synthetic polymer film formed on the substrate, wherein the synthetic polymer film has a plurality of convex portions (sometimes referred to as "first convex portions") on its surface, the equivalent diameter of the area circle of which is in the range of more than 20 nm and less than 500 nm when viewed from the normal direction of the synthetic polymer film, preparing a laminate; irradiating the plurality of convex portions of the laminate with the emitted light of a xenon lamp such that the irradiation light amount of light in the wavelength range of 300 nm or more and 400 nm or less is 6 MJ / m 2 or more; A manufacturing method comprising the above. [Item 2] Irradiating the emitted light of the xenon lamp is to irradiate the emitted light of the xenon lamp such that the irradiation light amount of light in the wavelength range of 300 nm or more and 400 nm or less is 22 MJ / m 2 or less, the manufacturing method according to Item 1. [Item 3] Irradiating the emitted light of the xenon lamp is performed in an environment with a relative humidity of 50% or less, the manufacturing method according to Item 1 or 2. [Item 4] Irradiating the emitted light of the xenon lamp is performed while continuously blowing air onto the surface of the synthetic polymer film, the manufacturing method according to any one of Items 1 to 3. [Item 5] The synthetic polymer film is formed of an ultraviolet curable resin, the manufacturing method according to any one of Items 1 to 4. [Item 6] Before irradiating the emitted light of the xenon lamp, irradiating the ultraviolet curable resin with ultraviolet light to form the synthetic polymer film with the ultraviolet curable resin, the manufacturing method according to Item 5. [Item 7] The plurality of convex portions include substantially conical convex portions with a bottom diameter of more than 20 nm and less than 500 nm, the manufacturing method according to any one of Items 1 to 6. [Item 8] The manufacturing method according to item 7, wherein the substantially oval convex portion includes a convex portion having a height of at least twice the diameter of the bottom surface. [Item 9] A laminate comprising a synthetic polymer film having antibacterial and / or antiviral properties, manufactured by the manufacturing method according to items 1 to 8. [Item 10] When viewed from the normal direction of the synthetic polymer film, the synthetic polymer film has a plurality of convex portions on its surface within a range where the equivalent diameter of the area circle is more than 20 nm and less than 500 nm. The laminate according to item 9, wherein the plurality of convex portions include a convex portion having a maximum length of the bottom surface more than twice the height. [Effect of the Invention]

[0006] According to an embodiment of the present invention, there are provided a laminate comprising a synthetic polymer film having excellent antibacterial and / or antiviral properties, and a manufacturing method thereof. [Brief Description of the Drawings]

[0007]

Fig. 1A

Fig. 1B

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[0008]

Fig. 2B

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Mode for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, a laminate including a synthetic polymer film having antibacterial and / or antiviral properties according to an embodiment of the present invention and a method for manufacturing the same will be described. The laminate including a synthetic polymer film having antibacterial and / or antiviral properties according to an embodiment of the present invention and the method for manufacturing the same are not limited to those exemplified below. Here, having antibacterial properties means that the antibacterial activity value obtained by a test method conforming to the JIS Z2801 standard is 2.0 or more, and having antiviral properties means that the antiviral activity value obtained by a test method conforming to ISO 21702:2019 is 2.0 or more.

[0010] The present applicant has developed a method for manufacturing an antireflection film (antireflection surface) having a moth-eye structure using an anodized porous alumina layer. By using the anodized porous alumina layer, a mold having an inverted moth-eye structure can be manufactured with high productivity (Japanese Patent Application Laid-Open No. 2009-166502, International Publication No. 2011 / 125486, International Publication No. 2013 / 183576). A synthetic polymer film having a moth-eye structure described in Patent Documents 1 to 4 on the surface and having a surface with a bactericidal action can be manufactured by applying this technology. The entire disclosure contents of Japanese Patent Application Laid-Open No. 2009-166502, International Publication No. 2011 / 125486, and International Publication No. 2013 / 183576 are incorporated herein by reference.

[0011] A method for manufacturing a laminate including a synthetic polymer film having antibacterial and / or antiviral properties according to the present invention has a substrate and a synthetic polymer film formed on the substrate. The synthetic polymer film has a plurality of convex portions on its surface with an equivalent circle diameter of the area being in the range of more than 20 nm and less than 500 nm when viewed from the normal direction of the synthetic polymer film. The step of preparing the laminate and irradiating the plurality of convex portions of the laminate with light emitted from a xenon lamp so that the irradiation light amount of light in the wavelength range of 300 nm or more and 400 nm or less is 6 MJ / m 2 or more. If the above irradiation light amount is less than 6 MJ / m 2 or more, the effect of improving antibacterial and / or antiviral properties may not be sufficiently obtained. For example, the pH value may not be able to be reduced to 5.0 or less.

[0012] First, referring to FIGS. 1A and 1B, a laminate 50A having a substrate 42 and a synthetic polymer film 34A formed on the substrate 42 is described. The synthetic polymer film 34A has a plurality of convex portions 34Ap on its surface with an equivalent circle diameter of the area being in the range of more than 20 nm and less than 500 nm when viewed from the normal direction of the synthetic polymer film 34A.

[0013] The laminate 50A shown in FIG. 1A has, for example, a base material 42 and a synthetic polymer film 34A formed on the base material 42. The synthetic polymer film 34A has a plurality of convex portions 34Ap on its surface, and the plurality of convex portions 34Ap constitute a moss-eye structure. When viewed from the normal direction of the synthetic polymer film 34A, the two-dimensional size Dp of the convex portion 34Ap is in the range greater than 20 nm and less than 500 nm. Here, the "two-dimensional size" of the convex portion 34Ap refers to the equivalent diameter of the area circle of the convex portion 34Ap when viewed from the normal direction of the surface. For example, when the convex portion 34Ap is conical, the two-dimensional size of the convex portion 34Ap corresponds to the diameter of the bottom surface of the cone, as shown in FIG. 1B. Also, the typical adjacent distance Dint of the convex portions 34Ap is greater than 20 nm and less than or equal to 1000 nm. As illustrated in FIG. 1A, when the convex portions 34Ap are densely arranged and there is no gap between adjacent convex portions 34Ap (for example, the bottom surfaces of the cones partially overlap), the two-dimensional size Dp of the convex portion 34Ap is equal to the adjacent distance Dint.

[0014] The typical height Dh of the convex portion 34Ap is 50 nm or more and less than 500 nm. The height Dh of the convex portion 34Ap may be 200 nm or less. The plurality of convex portions 34Ap includes, for example, substantially conical convex portions with a bottom diameter greater than 20 nm and less than 500 nm, and the substantially conical convex portions include convex portions with a height that is at least twice the bottom diameter. The substantially conical convex portions with a height that is at least twice the bottom diameter occupy, for example, 60% or more of the entire convex portion. Note that the plurality of convex portions 34Ap may not include substantially conical convex portions with a height that is at least twice the bottom diameter. Also, in the present embodiment, the plurality of convex portions 34Ap does not include convex portions included in the plurality of convex portions 34Bp described later, where the maximum length of the bottom surface is more than twice the height. There is no particular limitation on the thickness ts of the synthetic polymer film 34A, as long as it is greater than the height Dh of the convex portion 34Ap.

[0015] In addition, in this specification, the "moth-eye structure" refers not only to a nano surface structure with an excellent antireflection function composed of convex portions whose cross-sectional area (cross-section parallel to the film surface) increases as it approaches the substrate 42, such as the convex portion 34Ap of the synthetic polymer film 34A shown in FIG. 1A, but also includes a nano surface structure composed of convex portions having a portion with a constant cross-sectional area (cross-section parallel to the film surface). In order to destroy the cell wall and / or cell membrane of bacteria, it is preferable to have a conical portion. However, the tip of the cone may have a rounded shape.

[0016] The synthetic polymer film 34A having a moth-eye structure can be manufactured using a mold having the above-described inverted moth-eye structure. The synthetic polymer film 34A is preferably manufactured using an ultraviolet curable resin. The ultraviolet curable resin is cured by irradiating ultraviolet light of so-called "D bulb" (280 nm to 400 nm, peak wavelength 380 nm). As the ultraviolet curable resin, various known ultraviolet curable resins (for example, acrylic resins) can be used. A resin obtained by irradiating an ultraviolet curable (UV curable) resin with ultraviolet light and curing it is sometimes referred to as an ultraviolet cured (UV cured) resin. As the substrate 42, for example, various plastic films (for example, polystyrene, polyurethane, aromatic polyamide, polyester, polycarbonate) can be used. Polycarbonate (PC) having excellent light resistance and oxidation resistance is preferable.

[0017] The inventor has found that the antibacterial and / or antiviral properties can be improved by irradiating the plurality of convex portions 34Ap of the above laminate with light having an irradiation light amount in the wavelength range of 300 nm or more and 400 nm or less of 6 MJ / m 2 or more. Although there is no particular upper limit to the irradiation light amount, exceeding 22 MJ / m 2 will not improve the antibacterial and / or antiviral properties. From the viewpoint of mass productivity, the irradiation light amount may be 22 MJ / m 2 or less. Further, when the above irradiation light amount is 22 MJ / m 2When it exceeds, the synthetic polymer film may turn yellow. For example, when the intensity of light in the wavelength range of 300 nm or more and 400 nm or less is 60 W / m 2 , it may be irradiated for 30 to 100 hours. For example, by using a xenon arc lamp (Xenon Weather Meter XL75 manufactured by Suga Test Instruments Co., Ltd.) and irradiating from a position 290 mm away from the synthetic polymer film 44A, light with an intensity of about 60 W / m 2 in the wavelength range of 300 nm or more and 400 nm or less can be irradiated.

[0018] When the synthetic polymer film (preferably an ultraviolet curable resin) is irradiated with light in the wavelength range of 300 nm or more and 400 nm or less, the chemical bonds constituting the synthetic polymer film are broken, and well-known auto-oxidation occurs. The radicals and intermediate products generated by the photochemical reaction further auto-oxidize to generate radicals and acids. The mechanism of auto-oxidation is represented, for example, as shown in FIG. 9. The generated radicals and the like attack the proteins on the surface of bacteria and / or viruses, extract hydrogen, and decompose the proteins. Alternatively, the acids generated by the photochemical reaction can make it difficult for bacteria and / or viruses to survive. In addition, it is known that organic components having aldehyde-based, carboxylic acid-based, and ester-based chemical structures can damage proteins such as DNA, RNA, and enzymes, and an ultraviolet curable resin film or a substrate that generates them by a photochemical reaction may also be used.

[0019] Note that the step of irradiating the emitted light of the xenon lamp is preferably performed in an environment with a relative humidity of 50% or less. This is because hydrolysis may occur depending on the ultraviolet curable resin. In addition, the step of irradiating the emitted light of the xenon lamp is preferably performed while continuously blowing air onto the surface of the synthetic polymer film 34A. During this time, the synthetic polymer film 34A is preferably placed in an environment of about 50°C or less.

[0020] Next, with reference to FIGS. 2A and 2B, the structure of the laminate 50B having the synthetic polymer film 34B after being irradiated with the emitted light of the xenon lamp will be described. FIG. 2A is a schematic cross-sectional view of the laminate 50B including the synthetic polymer film 34B irradiated with the emitted light of the xenon lamp on the synthetic polymer film 34A, and FIG. 2B is a schematic plan view showing the convex portions 34Bp as viewed from the normal direction of the synthetic polymer film 34B.

[0021] As shown in FIG. 2A, as a result of the decomposition of the plurality of convex portions 34Ap of the synthetic polymer film 34A shown in FIG. 1A, the plurality of convex portions 34Bp of the synthetic polymer film 34B have a lower height Dh, and the top of the convex portion that was substantially conical becomes rounded. Convex portions having a flat top may also be formed. Also, the bottom of the concave portion between adjacent convex portions 34Bp is rounded. Concave portions having a flat bottom may also be formed between adjacent convex portions 34Bp. The variation in the shape and size of the plurality of convex portions 34Bp increases. The plurality of convex portions 34Bp include convex portions whose maximum length (here Dx) of the bottom surface is more than twice the height Dh. Also, the plurality of convex portions 34Bp may include convex portions whose maximum length of the bottom surface is three times or more the height Dh. The plurality of convex portions 34Bp may or may not include substantially conical convex portions having a height of two times or more the diameter of the bottom surface, which were included in the plurality of convex portions 34Ap. Note that the maximum length of the bottom surface of the convex portion is the maximum value of the distance between two points on the outer periphery of the bottom surface of each individual convex portion.

[0022] Also, as shown in FIG. 2B, when viewed from the normal direction of the synthetic polymer film 34B, the maximum length (here Dx) of the bottom surface of the convex portion 34Bp is substantially equal to the minimum length of the bottom surface (here the length Dy in the direction orthogonal to Dx), and Dx / Dy is less than 2.0. The shape of the bottom surface of the convex portion 34Bp is substantially circular.

[0023] Experimental examples will be described with reference to FIGS. 3 and 4.

[0024] A synthetic polymer film having a moth-eye structure was formed on a polycarbonate-based film. A resin material (solvent-free) prepared by blending polyethylene glycol diacrylate (M280: manufactured by MIWON SPECIALTY CHEMICAL CO., LTD), trimethylolpropane triacrylate (M300: manufactured by MIWON SPECIALTY CHEMICAL CO., LTD), 2-(2-vinyloxyethoxy)ethyl acrylate (VEEA: manufactured by Nippon Shokubai Co., Ltd.), and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Omnirad2959: manufactured by IGM Resins B.V.) as a polymerization initiator in a mass ratio of M280:M300:VEEA:Omnirad = 55:10:35:1 was applied onto the polycarbonate-based film to a desired thickness, and then irradiated with a D lamp (320 - 400 nm, 1200 W / m 2 ) for about 15 seconds (22500 J / m 2 ). The moth-eye structure had Dp = Dint = 200 nm and Dh = 200 nm.

[0025] Figure 3 shows the surface SEM image of the synthetic polymer film having the moth-eye structure. It can be seen that a plurality of substantially conical protrusions are densely formed. The plurality of protrusions on the surface of the synthetic polymer film shown in Figure 3 have the characteristics of the plurality of protrusions 34Ap described with reference to Figure 1A, and include substantially conical protrusions whose height is more than twice the diameter of the bottom surface. The substantially conical protrusions whose height is more than twice the diameter of the bottom surface, for example, account for more than 60% of the entire protrusions. There are also substantially conical protrusions whose height is less than twice the diameter of the bottom surface.

[0026] Figure 4 shows the xenon lamp emission light (60 W / m 2 ) applied to the synthetic polymer film having the above-described moth-eye structure for 100 hours (about 22 MJ / m 2)The SEM image of the surface of the synthetic polymer film after irradiation is shown. The convex portions of the moth-eye structure seen in Fig. 3 have become lower in height due to decomposition. There are also approximately conical convex portions, but the tops of many of the convex portions are rounded. In addition, convex portions with flat tops are also formed. The bottoms of the concave portions between adjacent convex portions are also rounded, and concave portions with flat bottoms are also formed between adjacent convex portions. The variation in the shape and size of the plurality of convex portions has increased. There are convex portions where the maximum length of the bottom surface (here, generally in the horizontal direction, sometimes referred to as "width") is more than twice the height, but generally, the width of the convex portions is from 1 to 2 times the height, and there are many convex portions with a width of 1.0 to 1.5 times the height. However, the plurality of convex portions may include convex portions where the maximum length of the bottom surface is 3 times or more the height (for example, the convex portions near the center in Fig. 4).

[0027] Next, refer to Fig. 5. Fig. 5 is a graph showing the time change of pH with or without xenon lamp irradiation. That is, it is an evaluation of how the surface of the synthetic polymer film having a moth-eye structure chemically changes by xenon lamp irradiation based on the time change of pH. The horizontal axis of the graph represents the test solution contact time. The same synthetic polymer film as in Fig. 4 was used for the sample. The pH was measured by a method corresponding to the antiviral test. Specifically, it was measured as follows.

[0028] After dropping 0.1 ml of EMEM dilution (a solution obtained by diluting EMEM 10-fold with sterilized distilled water) onto the surface having the moth-eye structure of the sample placed in a petri dish, the same as the virus suspension, a contact film (polyethylene film) was covered, and it was gently pressed so that the dilution spread over the entire film. In this state, the petri dish was covered and left at 25 °C for 24 hours. Then, the contact film was removed, and the pH of the test solution on the sample surface was measured using a flat ISFET pH electrode manufactured by Horiba, Ltd.

[0029] As shown in Fig. 5, when the test solution contact time is 0 hours, the pH value (5.68) of the xenon lamp-irradiated synthetic polymer film is smaller than the pH value (8.05) of the synthetic polymer film without xenon lamp irradiation and is in the acidic region. This is presumably because a photochemical reaction occurs on the surface of the synthetic polymer film by xenon lamp irradiation, generating an acid component. When the test solution contact time is 24 hours, the pH value (8.09) of the synthetic polymer film without xenon lamp irradiation hardly changes, while the pH value (3.60) of the synthetic polymer film irradiated with the xenon lamp becomes even smaller. This indicates that an auto-oxidation reaction is occurring on the surface of the synthetic polymer film irradiated with the xenon lamp due to radicals and intermediate products generated in the resin by the photochemical reaction.

[0030] Fig. 6 shows the results of antibacterial properties evaluated by the method compliant with JIS Z2801 (ISO22196). Bacterial suspensions were inoculated onto the xenon lamp-irradiated samples and the non-irradiated samples, respectively. After contacting the samples with bacteria for 24 hours, the number of bacteria on the samples was measured by the plaque measurement method, and the antibacterial activity value was calculated by comparing the amount of bacteria on the xenon lamp-irradiated samples and the non-irradiated samples.

[0031] As the bacterial species, Staphylococcus aureus (one-dot chain line and solid line in Fig. 6) and Escherichia coli (two-dot chain line and broken line in Fig. 6) were used. For these bacteria, no antibacterial effect was observed in the moss-eye structure without xenon lamp irradiation, while the antibacterial activity value of the synthetic polymer film having the moss-eye structure irradiated with the xenon lamp was more than 2.0 for any bacterial species, indicating that the antibacterial property was improved by xenon lamp irradiation. The antibacterial activity value was determined as follows. Antibacterial activity value = log (number of bacteria after 24-hour culture of the unprocessed product) - log (number of bacteria after 24-hour culture of the antibacterial processed product) Staphylococcus aureus activity value ≧ 4.4 = 4.25 - (-0.2) Escherichia coli activity value ≧ 3.9 = 3.7 - (-0.2)

[0032] Note that "-0.2" means the detection limit.

[0033] Figures 7 and 8 show the results of evaluating the antiviral property by a method compliant with ISO21702:2019.

[0034] As virus species, influenza virus A (enveloped virus) (Figure 7) and feline calicivirus (non-enveloped virus) (Figure 8) were used.

[0035] As can be seen from Figures 7 and 8, by performing xenon lamp irradiation, the antiviral effect is improved, and an antiviral activity value exceeding 2.0 was obtained for any virus. The antiviral activity value was determined as follows. Antiviral activity value = log (number of viruses after 24-hour culture of the unprocessed product) - log (number of viruses after 24-hour culture of the antiviral processed product) Influenza activity value ≥ 3.4 = 4.16 - 0.8 Feline calicivirus activity value ≥ 2.7 = 5.49 - 2.83

[0036] Here, an example of irradiating a synthetic polymer film having a moth-eye structure with a xenon lamp was shown. However, even if it does not have a moth-eye structure, by irradiating a synthetic polymer film with a xenon lamp, a chemical reaction such as auto-oxidation occurs, decomposes, and a resin material in which a fine uneven structure is formed (the surface becomes rough) is used, it is considered that antibacterial and / or antiviral properties can be improved. The irradiation conditions of the xenon lamp may be the same as those in the case of the synthetic polymer film having the exemplified moth-eye structure.

Industrial Applicability

[0037] The method for manufacturing a laminate including a synthetic polymer film having antibacterial and / or antiviral properties according to an embodiment of the present invention enables the provision of a laminate having improved antibacterial and / or antiviral properties as compared with the prior art. According to an embodiment of the present invention, a laminate including a synthetic polymer film having antiviral properties against both enveloped viruses and non-enveloped viruses can be provided.

Explanation of Reference Numerals

[0038] 34A and 34B synthetic polymer membranes 34Ap and 34Bp convex portions 42 base material 50A and 50B laminates

Claims

1. A method for manufacturing a laminate comprising a synthetic polymer film having antibacterial and / or antiviral properties, comprising a substrate and a synthetic polymer film formed on the substrate, wherein the synthetic polymer film has a plurality of convex portions on its surface within a range where the equivalent diameter of the area circle is more than 20 nm and less than 500 nm when viewed from the normal direction of the synthetic polymer film, and preparing a laminate. Irradiate the plurality of convex portions of the laminate with the emitted light of a xenon lamp so that the amount of irradiated light of light in a wavelength range of 300 nm or more and 400 nm or less is 6 MJ / m ２ or more, and A manufacturing method including this.

2. Irradiating the emitted light of the xenon lamp means that the irradiation light amount of light in a wavelength range of 300 nm or more and 400 nm or less is 22 MJ / m ２ or less. The manufacturing method according to claim 1, which is to irradiate the emitted light of the xenon lamp.

3. The method according to claim 1 or 2, wherein irradiating the emitted light of the xenon lamp is performed in an environment where the relative humidity is 50% or less.

4. The method according to claim 1 or 2, wherein irradiating the emitted light of the xenon lamp is performed while continuously blowing air onto the surface of the synthetic polymer film.

5. The method according to claim 1 or 2, wherein the synthetic polymer film is formed of an ultraviolet curable resin.

6. The method according to claim 5, including forming the synthetic polymer film with the ultraviolet curable resin by irradiating the ultraviolet curable resin with ultraviolet light before irradiating the emitted light of the xenon lamp.

7. The method according to claim 1 or 2, wherein the plurality of convex portions include substantially conical convex portions having a bottom diameter of more than 20 nm and less than 500 nm.

8. The method according to claim 7, wherein the substantially conical convex portions include convex portions having a height that is 2 times or more the diameter of the bottom surface.

9. A laminate comprising a synthetic polymer film having antibacterial and / or antiviral properties, manufactured by the manufacturing method according to claim 1 or 2.

10. The synthetic polymer film has a plurality of convex portions on its surface within a range where the equivalent diameter of the area circle is more than 20 nm and less than 500 nm when viewed from the normal direction of the synthetic polymer film, The laminate according to claim 9, wherein the plurality of convex portions include convex portions having a maximum length of the bottom surface that is more than 2 times the height.

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