JP2010247450A - Antibacterial film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antibacterial film which is flexible and can be applied to an arbitrary site and has excellent antibacterial performance. <P>SOLUTION: This antibacterial film has at least, one layer of antibacterial metallic thin film formed of preferably, silver, copper or their alloy, on at least, one side surface of the flexible polymer film base material. The metallic thin film is an antibacterial film formed through a vacuum vapor deposition process to thermally melt a metallic evaporation source. That is, it is preferable to form a pressure-sensitive adhesive layer on one side surface of the base material and also form an antibacterial metal on the opposite side surface to the side where at least the pressure-sensitive adhesive layer is formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

    The present invention relates to an antibacterial film that is installed on the surface of a building, equipment, furniture, etc. to reduce harmful microorganisms that inhabit the surface.

  To prevent contact infection and poisoning caused by harmful microorganisms such as pathogens attached to interiors such as floors and walls, equipment, furniture, etc. There is a strong demand for keeping the surfaces of equipment and furniture sterile. The risk of contact infection has long been recognized and cleaning with water wipes and various disinfectants has been enforced. However, a great deal of labor and caution is required to completely clean all interiors, equipment, and fixtures without leaving any surface, and food poisoning and nosocomial infection due to contact infection cannot be completely prevented. Currently.

  Under such circumstances, in order to effectively reduce harmful microorganisms with less effort, materials containing substances that have an effect of killing or suppressing the growth of microorganisms, that is, antibacterial agents, have been used. An example is the painting of floors with antibacterial agents in hospitals and food factories. In addition, in order to more easily impart harmful microorganisms to the surface, antibacterial wallpaper or the like in which an antibacterial agent has been kneaded has been widely installed. In particular, antibacterial metals such as copper are effective against a wider range of harmful microorganisms than organic antibacterial agents and are less toxic to the human body. For example, copper thin films such as paper and film It is proposed in Patent Documents 1 to 8 and Non-Patent Document 1 to be provided on a flexible substrate.

However, the antibacterial film as described above has not always been sufficiently useful due to the following problems. What is kneaded with organic antibacterial agent or coated on the surface is limited in the type of fungus that acts, and there is a high risk that bacteria having resistance to the antibacterial agent will appear. However, it was not always enough.
On the other hand, although the inorganic antibacterial agent is relatively excellent in reducing bacteria, the antibacterial agent is not exposed on the entire surface of the film when the antibacterial agent is kneaded into a polymer material. There was a problem that harmful microorganisms attached to the unexposed part of the antibacterial agent survive without being affected by the antibacterial agent.
On the other hand, although a film in which an antibacterial metal thin film is formed on the entire surface of the film has been proposed, rigorous evaluation of its effect and more effective configuration and means have not been studied in detail. .

JP-A-11-179870 JP2004-183030 JP 61-182943 Japanese Patent No. 2947934 Special table hei 9-505112 Special table hei 8-500392 JP 2006-152353 A

Toyama Prefectural Industrial Technology Center, 1997 report p.II-73

  An object of this invention is to provide the antibacterial film which is flexible, can be installed in arbitrary places, and is excellent in antibacterial performance.

  In view of the above problems, the present inventors have paid attention to the fact that the structure and density of the metal thin film differ depending on the method of forming the thin film. A detailed study has been made on the relationship. As a result, it was discovered that the degree of expression of the antibacterial effect varies depending on the thin film formation method, and the present invention has been completed. In other words, the present invention is an antibacterial metal thin film manufactured by another manufacturing method by using a thin film (hereinafter referred to as vapor deposition method) formed by a vacuum evaporation method (hereinafter referred to as vapor deposition method) performed by heating and melting a metal evaporation source. Higher antibacterial activity. When a metal thin film is formed on a plastic substrate, if the film thickness is relatively thin, use a sputtering method with excellent film thickness controllability and adhesion to the substrate, or use film thickness controllability and A vapor deposition method that is inferior in adhesion but excellent in productivity is generally used. Further, when the film thickness is increased to about 1 micrometer or more, it is general to use a copper foil manufactured by electrolytic plating or electrolytic refining on the base material.

  Among these production methods, the reason why the deposited film exhibits higher antibacterial activity than metal thin films formed by other methods is not clear. However, since the deposited film has a lower film density than a metal layer formed by sputtering or plating, it is considered that the oxidation reaction of the metal by moisture or oxygen in the air occurs faster. It is considered that this high oxidation reaction rate accelerates the generation of active oxygen and metal ions, which are active substances that kill bacteria, and a greater bactericidal power is obtained.

  As is clear from the antibacterial test results of the examples and comparative examples, the antibacterial film of the present invention can kill more bacteria in a shorter time than an antibacterial film formed by the same method with other antibacterial metals. .

The antibacterial film of the present invention is installed on the surface of building materials such as walls, floors, ceilings, window frames, closet linings, handrails and doorknobs, or furniture or interior decorations such as tables, cupboards, work tables, and curtains. This reduces the risk of health damage by suppressing the growth of moths and harmful bacteria in the indoor environment at a lower cost and more effectively than the antibacterial films, copper foils and copper plates that have been proposed in the past. be able to.
Furthermore, by installing the antibacterial film of the present invention in a state where it can be easily removed, unlike the case where the object itself such as building materials, furniture or upholstery is subjected to antibacterial processing, By removing or replacing with another film, it becomes easy to maintain a good environment.

  A high antibacterial effect can be obtained by forming the antibacterial metal by a vacuum deposition method in which a metal evaporation source is heated and melted. As a means for heating and melting a metal evaporation source, a method of heating by irradiating an electron beam (so-called EB vapor deposition), energization heating, induction heating, etc. are generally used because of good controllability of a film formation rate. All heating methods are available. By adopting a vapor deposition method in which the metal evaporation source is heated and melted and further evaporated by these heating methods, compared to using other metal thin film forming methods such as sputtering and electrolytic deposition (plating). A high effect of reducing harmful microorganisms can be obtained.

The constituent material of the antibacterial metal layer is most preferably selected from copper, silver, a copper alloy, and a silver alloy, but transition metals such as zinc, platinum, iron, cobalt, and molybdenum as metals having low toxicity to the human body, Aluminum and other alloys containing the above metals can also be used.
In addition, in order to install and fix the antibacterial film at a desired position, an adhesive layer is formed on one side of the substrate, and an antibacterial metal is formed on the side opposite to the side where the adhesive layer is formed. It becomes possible to fix easily by setting it as the formed structure. Furthermore, it is desirable to use a removable adhesive for the adhesive layer so that it can be easily removed when the antibacterial performance deteriorates as well as the installation. Also, depending on the choice of substrate, the peel strength from the adhesive layer is low, and when removed, the adhesive remains on the installation target, so-called adhesive residue is generated. In some cases, at least two layers are preferably formed so that the peel strength decreases in order toward the far side.

  Also, at least two layers of the antibacterial metal thin film are laminated, and the peel strength of the outermost pressure-sensitive adhesive layer that is not in contact with the antibacterial metal after lamination is higher than the peel strength of the other pressure-sensitive adhesive layers. By using an antibacterial film configured in advance so as to be large, when the antibacterial performance and appearance of the outermost layer deteriorate, the antibacterial performance and appearance can be easily recovered by removing only the outermost layer.

  By setting the film thickness of the antibacterial metal thin film to approximately 5 nanometers or more, the entire surface of the substrate can be completely covered with the metal thin film. On the other hand, when the film thickness of the antibacterial metal thin film is 1 micrometer or less, the risk of cutting the hand at the end face when handling the antibacterial film can be avoided. Furthermore, by making the film thickness of the antibacterial metal thin film 20 nm or less, light can be transmitted through the metal thin film, so that various designs applied to the substrate can be reflected in the appearance of the antibacterial film. It becomes possible, and it becomes possible to improve the design nature of the interior of a building or furniture or the entire interior decoration in which the antibacterial film is installed.

  Next, the present invention will be described in more detail based on examples and comparative examples. In addition, this invention is not restrict | limited at all by these examples.

  A pure copper thin film having a thickness of 50 is formed on one surface of a commercially available biaxially stretched polypropylene film (hereinafter referred to as OPP film, “Econege” (registered trademark) manufactured by Tosero Co., Ltd., film thickness 50 μm) by an electron beam heating vacuum deposition method. Nanometer formed. At this time, the pressure (Base Pressure) in the apparatus was 2 × 10 minus 4 Pascal, the purity of the copper of the vapor deposition source was 99.9% or more, and the formation rate of the copper thin film was 10 nanometers per second. The film with copper thin film thus prepared was cut into a size of 50 mm square, and E. coli and Staphylococcus aureus were tested based on JISZ2801: 2000 “Antibacterial processed product-Antibacterial test method / antibacterial effect”, in addition to the test time. In addition to the usual addition for 24 hours, the test was changed to 15 minutes and each sample was performed in triplicate. The results are shown in Table 1.

  A pure copper thin film having the same film thickness as that of Example 1 is formed on one surface of a commercially available biaxially stretched polyethylene terephthalate film (hereinafter referred to as “OPET film”, “OX” grade manufactured by Teijin DuPont Films Co., Ltd., film thickness 50 μm). did. The film with a copper thin film thus produced was cut into a size of 50 mm square and subjected to the same antibacterial test as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
A 50-nanometer pure copper thin film having the same film thickness as that of Example 1 was formed on one surface of an OPP film having the same specifications as in Example 1 by high-frequency sputtering. At this time, the pressure in the apparatus (Base Pressure) is 2 × 10 minus fourth power Pascal, the film formation atmosphere gas is argon, the pressure during film formation is 0.5 Pascal, and the formation rate of the copper thin film is 0.02 nanometers per second. The copper purity of the sputtering target was 99.9% or higher. The film with a copper thin film thus produced was cut into a size of 50 mm square and subjected to the same antibacterial test as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
A pure copper thin film having the same thickness as that of Comparative Example 1 was formed on one surface of an OPET film having the same specifications as in Example 2. The film with a copper thin film thus produced was cut into a size of 50 mm square and subjected to the same antibacterial test as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
A commercially available electrolytic copper sheet was cut into a size of 50 mm square to make a test object, and the same antibacterial test as in Example 1 was performed. The results are shown in Table 1.

Claims (4)

An antibacterial film formed by forming at least one antibacterial metal thin film on at least one surface of a flexible polymer film substrate, and the metal thin film is formed by a vacuum evaporation method in which a metal evaporation source is heated and melted the film. The antibacterial film according to claim 1, wherein the material of the antibacterial metal thin film is at least one metal selected from the group consisting of copper, silver, a copper alloy, and a silver alloy. The antibacterial film according to claim 1 or 2, wherein an adhesive layer is formed on one side of the substrate, and an antibacterial metal is formed on at least the side opposite to the side where the adhesive layer is formed. The antibacterial film according to claim 3, wherein a releasable pressure-sensitive adhesive layer is formed.