JPH11276985A - Antibacterial mildewproof precoated steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject steel sheet exhibiting a sufficient antibacterial mildewproof effect with the physical properties such as coating film strength comparable to the conventional precoated steel sheet. SOLUTION: A precoating film contg. an antibacterial mildewproofing agent composed of 2,3,4,5,6-tetrachloro-4-(methylsulfonyl)pyridine, 2,4,5,6- tetrachloroisophthalyl, 1,2,-benzisothiazolone, 2- methylcarbonylaminobenzimedazole and diiodomethyl-p-tobylsulfone is formed on the steel sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precoated steel sheet having antibacterial properties, and more particularly to an antibacterial precoated steel sheet suitable for use in each member constituting an air conditioner.

[0002]

2. Description of the Related Art Steel sheets whose surfaces have been subjected to a coating treatment (so-called "PCM steel sheets", also known as "color steel sheets") are used in many fields including home appliances.
For example, in an air conditioner, it is used for a portion such as a front panel of an outer box of an outdoor unit. An air conditioner is made up of many members, and a synthetic resin material, a pre-coated steel plate, a metal material such as aluminum is used as a material for the members. Synthetic resin material has properties as a dielectric material or an electrical insulating material, so it easily absorbs dust, bacteria and mold in the air, and when temperature and humidity conditions are uniform, bacteria and mold grow on the surface. It's easy to do. Since the main component of the precoat film is a binder made of a synthetic resin, the steel sheet provided with the precoat film has the same problem as a synthetic resin molded product. In addition, since air flows through the interior of the air conditioning equipment, dust, mold, and bacteria in the air are apt to adhere.In summer, dew condensation occurs. It has easy conditions. For this reason, among the members constituting the air conditioner, the members that come into contact with the air flow are particularly members having antibacterial properties, such as antibacterial synthetic resin, heat exchanger aluminum fins provided with antibacterial coating, and antibacterial precoat. Attempts have been made to use a steel sheet provided with a coating. This is because the antibacterial agent contained therein gradually oozes out of the surface of the molded article or coating from the synthetic resin molded article to which the antibacterial agent is added or the coating to which the antibacterial agent is added (bleed out).
By doing so, it is expected that an antibacterial and antifungal effect will be imparted to the surface of a molded article or a coating.

In this case, as described above, in the air conditioning equipment, dew condensation occurs in the summer and warm air flows in the winter, so that in addition to the physical properties required for general synthetic resin molded products and coating films, the air conditioning equipment further includes It is required that the antibacterial and antifungal agent in the resin molded product and the coating film does not dissolve into the dew condensation water and that it does not volatilize excessively in warm air. Furthermore, the antibacterial and antifungal agent is required to have performances such as a broad antibacterial spectrum (effective against many types of molds and bacteria), high safety, and long-lasting effects. As for the antibacterial precoated steel sheet, since the precoat film is a relatively thin film (10 to 40 μm), a large amount of the antibacterial agent adversely affects the physical properties of the film itself. It is necessary to exhibit a proper and effective antibacterial effect, and it is also required that the precoat film be stable at the baking temperature. However, a steel sheet provided with an antibacterial precoat film that satisfies all of the above performances has not yet appeared, and its development has been desired.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to exhibit a sufficient antibacterial and antifungal effect and to improve physical properties such as film strength by conventional precoat coating. An object of the present invention is to provide a steel sheet on which a pre-coated film is formed, which is comparable to the above.

[0005]

The above object is achieved by providing the following steel sheet. (1) A steel sheet on which a precoat film containing an antibacterial and antifungal agent having the following composition is formed. 1.2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine 2.2,4,5,6-tetrachloroisophthalyl 3.1,2-benzisothiazolone 4.2-methoxycarbonylaminobenz Imidazole 5. Diiodomethyl-p-tolylsulfone (2) The steel sheet according to the above (1), wherein the precoat film further contains a surfactant.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the precoat film of the antibacterial and antifungal precoated steel sheet of the present invention, a conventionally used paint for a precoated steel sheet using, for example, an acrylic resin or a polyester resin as a binder can be used without any particular limitation. In the present invention, a baking type is particularly preferably used.
Components used in ordinary precoat paints, such as isocyanate compounds, curing agents such as amino resins, pigments / dyes, etc., can be added to the paints as needed. Also,
Either solvent type or aqueous type paints can be applied. The precoat paint for the antibacterial and antifungal precoated steel sheet according to the present invention is characterized by containing, as an antibacterial and antifungal agent, a composite antibacterial and antifungal agent having the following composition. 1.2,4,5,6-tetrachloroisophthalonitrile 2.2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine 3.1,2-benzisothiazolin-3-one 4. Methyl (benzimidazol-2-yl) carbamate Diiodomethyl-p-tolylsulfone

The proportion of each component used in the antibacterial and antifungal composition used in the present invention is 5 to 40% by weight of 2,4,5,6-tetrachloroisophthalonitrile, preferably 15% by weight.
~ 25% by weight, 2,3,5,6-tetrachloro-4-
(Methylsulfonyl) pyridine is 5 to 40% by weight, preferably 10 to 20% by weight, and 1,2-benzisothiazolin-3-one is 5 to 40% by weight, preferably 10 to 20% by weight.
1 to 20% by weight, preferably 5 to 15% by weight of methyl (benzimidazol-2-yl) carbamate, and 5 to 80% by weight of diiodomethyl-p-tolylsulfone, preferably 30 to 50% by weight. Can be used with The combination of the above antibacterial agents not only complements each other's effects against weaker bacteria in each antibacterial spectrum, but also exerts a stronger antibacterial effect by a synergistic effect. It has a broad antibacterial spectrum, and is effective at a relatively low concentration on many types of molds and bacteria. In addition, the safety to the human body is high,
The effect lasts for a long time because it is hardly eluted by hot water or the like. Further, the antibacterial and antifungal agent of this composition has high heat resistance and is stable even at high temperatures, so that there is no occurrence of deterioration or decomposition due to heating during baking of the precoat paint. Furthermore, it is not decomposed by ultraviolet rays, acid alkalis and organic solvents and has high chemical stability.

The composite antibacterial / antifungal agent used for the antibacterial / antifungal precoated steel sheet of the present invention is 0.0
It is used in an amount of 0.5 to 5% by weight, preferably 0.1 to 1.0% by weight. If the amount is less than 0.005% by weight, the desired antibacterial and fungicide action cannot be obtained. If the amount is more than 5% by weight, the physical properties of the precoat film may be impaired, such as discoloration of the precoat film. The composite antibacterial and antifungal agent comprising the above five components of the present invention can provide desired antibacterial and antifungal properties by adding a smaller amount thereof as compared with the case where a conventional antibacterial and antifungal agent is used. Therefore, it is possible to minimize the influence of the antibacterial and antifungal agent on the paint.

In the present invention, it is preferable to add a surfactant in addition to the above antibacterial and antifungal agent. Surfactants include anionic, cationic, amphoteric and nonionic surfactants. Specifically, as anionic surfactants, alkyl benzene sulfonates, alkyl phenyl sulfonates, alkyl naphthalene sulfones Acid salts, higher fatty acid salts, higher fatty acid ester sulfate salts, higher fatty acid ester sulfonic acids, and the like can be used. As the cationic surfactant, primary to tertiary amine salts, quaternary ammonium salts and the like can be used. As the amphoteric surfactant, alkyldimethyl betaine, aminocarboxylate, imidazolinium betaine and the like can be used. Examples of nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, and polyoxyethylene. Alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester,
Fatty acid alkylolamide and the like can be used. Among them, a nonionic surfactant can be preferably used. The surfactant in the present invention helps the antibacterial and fungicide to bleed out from the surface of the precoat film. Further, since the surfactant has an antistatic effect, it prevents the adhesion of bacteria and mold such as dust, and in combination with the above-described effect of promoting bleed-out, it is possible to further enhance the antibacterial and antifungal properties of the surface of the precoated steel sheet. Needless to say, the precoated steel sheet of the present invention has an effect of making it difficult to adhere hand stains and dust in the air. In the present invention, the amount of the surfactant added is 0.5 to 2% by weight, preferably 1 to 1.
5% by weight is added. If it is less than 0.5% by weight, it is difficult to obtain the above-mentioned effects, and if it is more than 2% by weight, the coating strength is undesirably reduced.

[0010] To prepare the antibacterial and antifungal precoated steel sheet of the present invention, the steel sheet is subjected to degreasing, chemical conversion treatment, surface conditioning treatment, or the like, or a precoated paint containing an antibacterial and antifungal agent is applied and dried. Obtained by baking. In order to mix the antibacterial and fungicide in the precoat paint, a solution in which the antibacterial and fungicide is dissolved in an organic solvent or a solution prepared in an aqueous dispersion is mixed with the paint. Alternatively, it may be directly mixed with the paint. The coating method is not particularly limited, and an ordinary coating method can be used. For example, spray coating, roll coating, dip coating, brush coating and the like can be applied. The baking varies depending on the material used, but 220-260.
C., preferably for 60 to 180 seconds.

[0011]

Next, examples of the present invention will be described, but the present invention is not limited to the following examples. Example 1 A 0.6 mm-thick steel plate surface was coated with a roll coater using a coating obtained by adding 1.0% by weight of an antibacterial antifungal agent having the following composition to a coating using polyester as a binder resin. After drying, baking was performed at 240 ° C. for 90 seconds to form a precoat film having a thickness of 20 μm. <Antimicrobial fungicide composition> 2,4,5,6-tetrachloroisophthalonitrile 20% by weight 2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine 20% by weight 1,2-benzisothiazoline -3-one 10% by weight methyl (benzimidazol-2-yl) carbamate 10% by weight diiodomethyl-p-tolylsulfone 40% by weight

The steel sheet on which the antibacterial and antifungal precoat film was formed was cut into a diameter of 27 mm, and the antibacterial and antifungal effect was evaluated. Further, a paint obtained by adding 1.0% by weight of a polyoxyethylene alkylphenyl ether which is a nonionic surfactant as a surfactant to the above-mentioned paint is used.
Similarly, a precoat film was formed on a steel plate, and the antibacterial and antifungal effect was similarly evaluated. For comparison, the above pre-coated paint was prepared without adding an antibacterial and fungicide, and was prepared by adding 1% by weight of TBZ (2- (4-thiazolyl) benzimidazole) instead of the antibacterial and fungicide. Was formed, and the antibacterial and antifungal effect was evaluated in the same manner. <Antibacterial test (halo-test)> First, in order to evaluate the persistence of the antibacterial and antifungal effect, heat resistance deterioration at 70 ° C. for 7 days and water resistance deterioration at running water for 7 days (flow rate of 2 L / min) were performed. A mold resistance test (halo test) was performed using the sample and a sample without deterioration. The sample was sterilized under the conditions of 100 ° C. steam / 5 minutes in order to eliminate the influence of contamination by various bacteria. Samples were stained with blue mold ( Penicillium c)
hrysinum IAM7106) was halved and cultivated at 25 ° C. for 7 days. Table 1 shows the results.

[0013]

[Table 1]

As can be seen from Table 1, the sample to which TBZ was added exhibited no antifungal property after the deterioration test, whereas the sample to which the antibacterial and antifungal agent of the present invention was added had an effect even after the deterioration test. Had lasted.

[0015]

As described above, according to the present invention, by adding an antibacterial and fungicide having a specific composition to a precoat paint, the bleedout of the antibacterial and fungicide from the precoat film formed from the precoat paint is good and it can be used for a long time. Since it can maintain antibacterial and antifungal properties over a long period of time and does not discolor under the influence of ultraviolet light or heat for a long period of time, the precoated steel sheet of the present invention is suitably used in places where environmental changes such as air conditioners are severe. be able to.

Claims (2)

[Claims] 1. A steel sheet having a precoated film containing an antibacterial and antifungal agent having the following composition. 1.2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine 2.2,4,5,6-tetrachloroisophthalyl 3.1,2-benzisothiazolone 4.2-methoxycarbonylaminobenz Imidazole 5. Diiodomethyl-p-tolylsulfone 2. The steel sheet according to claim 1, wherein the precoat film further contains a surfactant.