JPH0924376A - Porous compact for sterilization and antibacterial method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sterilizing method capable of effectively preventing the breeding of bacteria in an aq. liq. used by storing or circulating, inexpensive and excellent in maintenance and to provide a porous compact for sterilization suitable to be used for this method. SOLUTION: The porous compact for sterilization is formed by forming and burning a mixture of an inorg. antimicrobial agent and a ceramic starting material, especially, a cylindrical porous compact for sterilization is formed by burning the formed body after extruding the mixture of the inorg. antimicrobial agent and the ceramic starting material to the shape of a wire, winding up in a helical form and forming in cylindrical shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilizing porous molded article for sterilizing an aqueous liquid or an antibacterial method using the same, which is characterized by excellent maintainability and low cost.

[0002]

2. Description of the Related Art Many of aqueous liquids for industrial use or beverages are stored or circulated for use, and there is a problem of contamination due to propagation of bacteria during these processes. In order to avoid this, various methods for preventing the growth of bacteria and further sterilizing them have been proposed. As an antibacterial method, addition of an organic or inorganic bactericide to a target aqueous liquid, contact with an insoluble inorganic bactericide, irradiation with an ultraviolet germicidal lamp, or the like has been used. However, the sterilization method in which an organic chemical such as benzimidazole or an inorganic chemical such as sodium hypochlorite is added requires not only a large amount of chemicals but also an increase in processing cost, and addition of these chemicals is not allowed. It could only be applied to the intended use and lacked versatility.

Japanese Unexamined Patent Publication (Kokai) No. 5-15879 discloses a circulating water treatment apparatus equipped with a suspended matter removing device and a bacteria removing device. The sterilization device used here is a membrane filtration method, and this method cannot always sterilize sufficiently,
In order to perform sufficient sterilization, it is necessary to use a highly sophisticated microporous membrane, in which case the cost of the membrane is high and the filtration rate is slow, which is not satisfactory for this purpose in any case. . Further, JP-A-5-230492 discloses a method and apparatus for preserving a water-soluble oil agent.
According to this method, a liquid to be treated is caused to flow between electrodes arranged with a copper material as an anode, and by energizing, copper ions are mixed into the liquid to be treated so as to have a sterilizing and fungicidal effect. This method forcibly mixes copper ions of a certain concentration or more into the treatment liquid, and cannot be applied to a liquid that cannot mix these heavy metal ions.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to sterilize an inexpensive and maintainable aqueous liquid which can effectively prevent the growth of bacteria in the aqueous liquid used for storage or circulation. A method and a porous molded article for sterilization suitable for use in the above sterilization method.

[0005]

The present invention is directed to a sterilizing porous molded article obtained by molding and firing a mixture of an inorganic antibacterial agent and a ceramic raw material, and particularly a linear mixture of the inorganic antibacterial agent and the ceramic raw material. The present invention relates to a cylindrical sterilized porous molded body obtained by extruding, spirally winding this into a cylindrical shape, and then firing. Further, the present invention relates to a method for sterilizing an aqueous liquid, which comprises contacting a liquid to be treated with the sterilizing porous molded body. More specifically, the present invention relates to a method for sterilizing an aqueous liquid, characterized in that the sterilizing porous molded body is housed in a housing and is provided in a liquid channel of a liquid to be treated.

The sterilizing porous molded article of the present invention is kneaded with an inorganic antibacterial agent together with ceramics so as to prevent falling off and to maintain the effect, and to sterilize the molded article with a high specific surface area. By improving the effect and making it a cartridge type, the maintenance is facilitated, and the cost problem is solved by using an inexpensive raw material.

The inorganic antibacterial agent used in the sterilized porous molded article of the present invention is not particularly limited as long as it has a strong antibacterial effect and does not lose its antibacterial effect during the molding and firing steps. However, preferred are silver / zeolite, silver / zinc / zeolite, silver / copper /
Zeolite, zinc / zeolite, copper / zeolite (manufactured by Kanebo Kasei Co., Ltd.), silver / zirconium phosphate, silver / zinc / zirconium phosphate (manufactured by Toagosei Co., Ltd.), silver / calcium phosphate (manufactured by Sangi Co., Ltd.), Examples thereof include silver / zinc / alumina / silica / magnesia and silver / copper / alumina / silica / magnesia (manufactured by Catalysts & Chemicals Industry Co., Ltd.).
Particularly preferred inorganic antibacterial agents are those in which the carrier is zirconium phosphate and zeolite. The amount of the inorganic antibacterial agent mixed in the ceramics is 1 to 30% by weight, preferably 5 to 20% by weight based on the ceramics.

The ceramic raw materials that can be used for the present sterilizing porous molded body are kaolin, pyroferrite, talc, smectite, sepiolite, which can be calcined and molded.
Clay minerals such as attapulgite, and oxides, hydroxides, and carbonates of aluminum, magnesium, titanium, and silicon. Among them, kaolin, talc, sepiolite, attapulgite, alumina, silica and magnesia are particularly preferable.

The ceramics for forming the fired body can be made into a porous body by kneading, shaping and firing at least one of them having an average particle size of 1 μm or more together with a binder. The structure as a porous molded body has an average pore diameter of 0.5 to 50 μm and a specific surface area of 1 m ² / g or more, preferably 1 to 50 μm, 1.2 m ² or more, and a raw material to obtain such a porous structure. Select the average particle size and blending ratio. As the ceramic raw material, the same inorganic compound as that used as the carrier for the antibacterial metal may be used. Although it is all right to use the same one, even in that case, once this inorganic compound is used as a carrier to form an inorganic antibacterial agent, the same inorganic compound is used for the porous molded body in the next molding step. It is preferable to use it as a ceramic raw material. The inorganic antibacterial agent is firmly held on the carrier by ion exchange, adsorption or the like between the antibacterial metal and the carrier, and metal ions are hardly released. The ceramic raw material and the inorganic antibacterial agent are solidified by mixing and firing, and the inorganic antibacterial agent is firmly held in the ceramic and does not fall off.

The porous molded body can be manufactured as follows. After a predetermined amount of inorganic antibacterial agent is powder-mixed with the ceramic raw material, water is added and kneaded to obtain a kneaded product having an appropriate hardness that can be used for extrusion molding.
This kneaded product is put into an extruder, and if necessary, a strong shearing force is further applied in the extruder to add kneading, and the product is continuously extruded linearly from a die. A linear extrudate is spirally wound so as to obtain a cylindrical shape having a required diameter, and a cylindrical article having a constant length is obtained. This is air-dried at room temperature to remove water.

The cross section of the extruded linear object is generally circular, but it need not be a perfect circle, and may be elliptical or polygonal. Rather, a cross section having a large surface area such as a star shape is preferable. The diameter of the linear object is such that the diameter of the largest part is 0.5 to 5 mm, preferably 1 to 3 mm. 5 mm
If it is larger, the contact area with the liquid to be treated becomes smaller,
If it is smaller than 0.5 mm, the molded product becomes weak, which is not preferable. Further, it is not necessary that the number of linear objects extruded is one, and a plurality of linear objects may be bundled and formed into a cylindrical shape.

The size of the cylindrical molded article is 3 after the firing.
Those having a length of 0 to 70 mm and a length of 100 to 250 mm are convenient for handling.

The air-dried cylindrical molded body is then fired to obtain strength and simultaneously become porous. The firing is performed at a maximum temperature of 600 to 1200 ° C. for 0.1 to 10 hours. For the firing, the air-dried compact may be put directly into the furnace set to the firing temperature, but in order to avoid the occurrence of damage or cracks due to rapid heating, the air-dried compact should be completely removed of water by microwave heating. It is preferable to put it in a furnace kept at a temperature of 100 ° C or lower, and then raise the temperature inside the furnace to the required temperature. Also, after firing is completed, cool the temperature in the furnace to 100 ° C or lower before taking it out. Is preferred. When it is placed on a conveyor or the like and continuously fired, it is preferable to sequentially pass through each heating region whose temperature is controlled as a preheating zone, a firing zone and a cooling zone. In this way, a sterilized porous molded body is obtained.

The liquid to be treated can be sterilized by bringing the aqueous liquid to be treated into contact with the sterilizing porous molded body obtained as described above. Effective sterilization depends on the type of target bacteria, the type of antibacterial agent used, the relationship between the antibacterial agent and the concentration of bacteria, etc., but generally at a temperature of 0 to 50 ° C. It is necessary to contact for 0.1 to 5 hours, preferably 1 to 5 hours. When the liquid to be treated does not cause any inconvenience when heated, heating to 40 to 50 ° C. to bring them into contact with each other has a greater sterilizing effect, but 10 to 30 ° C. is generally sufficient. Sterilization treatment, the porous molded body for sterilization of the present invention, a water channel in which the liquid to be treated circulates, for example, may be filled in a column, if the molded body is used in a form stored in a housing in advance, There is little damage, and handling such as replacement of the molded body becomes easy. The housing is not particularly limited, and for example, a plastic case having many holes can be used.

The aqueous liquid which can be treated with the sterilizing porous molded article of the present invention includes fiber oils, water-soluble cutting oils, oils such as silicone release agents, surfactants and the like dissolved in water. Dispersed, suspended or emulsified liquids or water can be applied.

[0016]

The present invention will be described below in detail with reference to examples. Examples 1 to 4 Inorganic antibacterial agents shown in Table 1 and ceramic raw materials shown in Table 2 were kneaded by adding 10 parts of methyl cellulose and an appropriate amount of water. The kneaded product was continuously extruded into a linear product having a cross-sectional shape with a diameter of 2 mm. The linear object was sandwiched between guide rollers, and the guide rollers wound up and reciprocated in the axial direction on the bobbin, whereby the bobbin was spirally wound in multiple layers. The cylindrical molded body having an outer diameter of 70 mm and a length of 245 mm thus obtained was air-dried at room temperature and then placed in a microwave oven to completely remove residual moisture, and then placed in an electric furnace at the temperature shown in Table 3 Burned for hours. It was slowly cooled to 100 ° C. over 24 hours and taken out.
An antibacterial cartridge (porous molded body) having a weight of 300 g and a surface area of 400 m ² was obtained.

An emulsion of a fiber oil agent containing mineral oil, a surfactant and the like in a tank to which a filter housing (external diameter 75 mm, length 280 mm) manufactured by Organo Co., Ltd. is internally provided, and a circulation pump is connected. And circulated at room temperature. The top of the tank was opened so that bacteria falling in the air could enter. Circulation was continued continuously, and the aqueous solution in the tank was collected every week, and the collected aqueous solution was cultured on ordinary agar medium at 37 ° C. for 48 hours. The number of grown colonies was counted, and the results are shown in Table 4.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

Comparative Example 1 An antibacterial cartridge was prepared in the same manner as in Example 1 except that silver / zirconium phosphate was not added, and the cartridge was housed in a housing.
The same fiber oil agent as in Example 1 was circulated, and the circulating fluid was cultured on ordinary agar medium to count the viable cell count. The results are shown in Table 4 in comparison with Example 1.

[0023]

As is apparent from the examples, by installing the sterilizing porous molded article of the present invention in the circulating aqueous liquid channel, the growth of bacteria in the aqueous liquid is effectively prevented. be able to.

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Claims (7)

[Claims] 1. A sterilizing porous molded article obtained by molding and firing a mixture of an inorganic antibacterial agent and a ceramic raw material. 2. The sterilized porous molded article according to claim 1, wherein at least one of the ceramic raw materials has an average particle diameter of 1 micron or more, and the interparticle voids form pores after firing. 3. The sterilization according to claim 1 or 2, wherein a mixture of an inorganic antibacterial agent and a ceramic raw material is extruded in a linear shape, spirally wound into a cylindrical shape, and then fired. Porous molded product. 4. The inorganic antibacterial agent comprises at least one metal selected from the group consisting of silver, copper, zinc and nickel, zeolite,
Silica gel, zirconium phosphate, glass, apatite,
The sterilized porous molded article according to any one of claims 1 to 3, which is selected from at least one of a composite material in which at least one or more inorganic compounds are supported among alumina, titania, and magnesia. 5. The ceramic raw material is selected from at least one of attapulgite, kaolin, pyrophyllite, smectite, talc or sepiolite clay mineral, aluminum, magnesium, titanium or silicon oxide, hydroxide or carbonate. Claims 1, 2,
The sterilized porous molded article according to any one of 3 and 4. 6. A method for sterilizing an aqueous liquid, which comprises bringing a liquid to be treated into contact with the molded article according to any one of claims 1 to 5. 7. A method for sterilizing an aqueous liquid according to claim 6, wherein the molded product according to any one of claims 1 to 5 is housed in a housing and provided in a liquid channel of a liquid to be treated.