JPH11246213A - Antibacterial composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compsn. in which the itself does not cause a color change even under severe conditions and can be easily and homogeneously dispersed in a resin by compounding a cyclic compd. having imide hydrogen or its substituted compd. into an inorg. compd. carrying antibacterial metal ions. SOLUTION: As for an inorg. compd., zeolite is most preferable. As for an antibacterial metal ion, metal ions selected from silver, copper and zinc are used. Proper amts. of silver ion, copper ion and zinc ion in the inorg. compd. are 0.05 to 10%, 0.1 to 10% and 0.1 to 12%, respectively. As a cyclic compd. having imide hydrogen or its substituted compd., a compd selected from triazole, benzotriazole, imidazole and benzimidazole or its substituted compd. is appropriate. The proper compounding amt. of the compd. having imide hydrogen to the inorg. compd. carrying the antibacterial ions is 0.1 to 20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic antibacterial composition, and more particularly to an antibacterial zeolite which does not discolor over time during storage of the inorganic antibacterial composition. Further, the present invention relates to an antibacterial zeolite which does not discolor the antibacterial resin even when used by mixing in a resin or when molded. Further, the present invention relates to an antibacterial zeolite in which the antibacterial resin does not change its color even under the influence of heat or light over time after molding the resin.

[0002]

2. Description of the Related Art With respect to inorganic antibacterial agents carrying antibacterial metal ions, conventionally, metal ions such as silver ions, copper ions or zinc ions carried on inorganic compounds to impart antibacterial properties are converted to heat. It tends to be released from zeolite under the influence of light and light. For this reason, the antibacterial zeolite itself discolors during storage, or is kneaded with the resin and colored at the time of molding, and further, the antibacterial resin after molding is significantly discolored due to heat, light or moisture over time. In some cases, the merchantability was lost.

In order to solve these disadvantages, there has been disclosed an invention in which various discoloration inhibitors are added at the stage of kneading an inorganic (zeolite) antibacterial agent into a resin (Japanese Patent Application Laid-Open No. Sho 63).
-265858). However, in the method of kneading a benzotriazole-based compound having no imide hydrogen in the ring or other listed compounds immediately before molding of the resin, the antibacterial agent itself is persistent in the stage before kneading. The color tone of the resin may change from yellow to yellow-brown at the time when the resin undergoes discoloration and is kneaded and molded with the resin. Even if the antibacterial composition itself is not discolored (short storage period), metal ions are easily released at high temperatures such as during molding, and the function of suppressing such movement of metal ions is poor. Sometimes coloring is inevitable. Furthermore, after molding, the conventional disadvantages have not yet been sufficiently solved, such as the tendency for the color to change due to the influence of heat or light over time.

[0004]

The problem to be solved by the present invention is that the antimicrobial composition itself does not discolor even under severe conditions, and is easily and homogeneously contained in the resin. An object of the present invention is to provide an inorganic antibacterial composition which can be dispersed in water. Further, the inorganic antibacterial composition does not become colored even when the resin is molded, and the antibacterial property of the resin after the molding is maintained. It is still another object of the present invention to provide an inorganic antibacterial composition that does not discolor the resin under the influence of heat or light after resin molding, or under the influence of water containing alkali or acid.

[0005]

According to the present invention, there is provided an antibacterial composition comprising an inorganic compound carrying an antibacterial metal ion and a cyclic compound having imido hydrogen or a substituted compound thereof. This is to solve the above-mentioned problem. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As the inorganic compound (supporting antibacterial metal ions) in the present invention, for example, activated carbon,
Activated alumina, silica gel, glass, zeolite, hydroxyapatite, zirconium phosphate, titanium phosphate, hydrous titanium oxide, hydrous zirconium oxide, hydrous bismuth, hydrous antimony, hydrotalcite,
Examples include alumina and aluminum polyphosphate. In addition,
It is particularly suitable for zeolites, hydrated titanium oxide, hydrated zirconium hydrate, hydrated bismuth hydrate, hydrated antimony hydrate, etc. in that it is easily accompanied by desorption of metal ions due to the contained water of crystallization and inherently has factors such as discoloration. . Among them, zeolite having excellent ion exchange performance and capable of imparting high antibacterial properties is most preferable for the purpose of imparting antibacterial properties.

In the present invention, examples of a method for supporting an antibacterial metal ion on an inorganic compound include ion exchange, physical adsorption, chemical adsorption, a method using a binder, a vapor deposition method, and the like.
Alternatively, there is a thin film forming method or the like. Of these, ion exchange can strongly support metal ions such as silver ions,
Particularly preferred.

In the present invention, the antibacterial metal ion carried on the inorganic compound is at least one metal ion selected from the group consisting of silver ion, copper ion and zinc ion, and the content of silver ion in the inorganic compound Is 0.05-
An appropriate amount is 10%, preferably 0.1 to 5%. The content of the copper ion in the inorganic compound is 0.1 to 10%, and the content of the zinc ion is 0.1 to 12%.

In the present invention, the cyclic compound having imido hydrogen or its substituted compound to be mixed with the inorganic compound carrying the antibacterial metal ion is a cyclic compound selected from the group consisting of triazole, benzotriazole, imidazole and benzimidazole. The substitution is suitable. Specifically, 1H-1,2,4-triazole, benzotriazole, 5-methylbenzotriazole, 4-methylbenzotriazole, imidazole,
Examples include 2-methylimidazole, carboxybenzimidazole, and thiazolyl-1H-benzimidazole.

In the present invention, an appropriate amount of the compound having imide hydrogen is 0.1 to 20% with respect to the inorganic compound carrying antibacterial metal ions. If the blending amount is higher than this, the antibacterial property after compounding the resin is greatly reduced, and the necessary antibacterial property cannot be obtained.

In the present invention, as a method for obtaining an antibacterial composition of the present invention by blending a compound having imide hydrogen with an inorganic compound carrying an antibacterial metal ion, a triturator, a ball mill, a powder mixer or the like can be used. Is preferably used to make the powder particles uniform in size while achieving homogeneous dispersion.

The resin in which the antimicrobial composition of the present invention is mixed may be either a thermoplastic resin or a thermosetting resin. Specific resins include polyethylene, polypropylene, vinyl chloride, ABS resin, nylon, polyester polyvinylidene chloride, polyamide, polystyrene, polyacetal, polycarbonate, acrylic resin, fluororesin, polyurethane, urea resin, unsaturated polyester resin and the like. Can be The appropriate amount of the antibacterial composition mixed into the resin is 0.1 to 5%.

[0013] Of the resins used above,
For polyolefin-based resins for which chlorine-based polymerization catalysts are widely used, anions such as chlorine, which is a residue of the catalyst, may cause discoloration, so that an inorganic compound carrying an antibacterial metal ion has imido hydrogen. It is particularly preferable to mix and use an antibacterial composition obtained by combining a compound with an anion exchanger such as hydrotalcite. The compounding amount of the anion exchange agent in the antibacterial composition is 0.05 to
10% is preferred.

[0014]

Reference Example 1 (Preparation of antibacterial zeolite) Water was added to 1 kg of A-type zeolite powder having an average particle size of 5 microns, which was dried by heating at 100 ° C., and a 1.8-liter slurry was added. Add an aqueous solution and water, PH5-6
Was adjusted. To this slurry was added a mixed aqueous solution of salt whose salt concentration was adjusted so that silver nitrate and zinc nitrate became 0.1 M / l and 0.8 M / l, respectively, to make a total volume of 4.8 liters. The mixture was stirred day and night. After ion exchange, the zeolite phase was filtered and washed with water at room temperature until excess metal ions disappeared. Then, it was dried by heating at 200 ° C. to prepare an antibacterial zeolite. The contents of silver and zinc in the zeolite are 3.2% and 7.3%, respectively.
Met. Example 1 (Preparation of Antimicrobial Composition of the Present Invention) A predetermined amount of the antimicrobial zeolite powder described in Reference Example 1 and 100 parts by weight of the cyclic compound having imido hydrogen described in Table 1 or a predetermined amount thereof was mortared. And thoroughly kneaded to obtain five kinds of the antibacterial compositions of the present invention of the present invention. As a control, a benzotriazole-based light stabilizer Tinuvin 3 manufactured by Ciba-Geigy having no imide hydrogen in the ring.
20, and hydrazine-based light stabilizer Irganox MD1024 manufactured by Ciba-Geigy, which is a non-cyclic compound while retaining imido hydrogen, was kneaded in the same manner as above to prepare an antibacterial composition. Test Example 1 (Discoloration test of invention antibacterial composition) The various antibacterial compositions of the present invention described in Example 1 and the control product, and the antibacterial zeolite powder described in Reference Example 1 alone were also used, respectively. 10 g was collected in a glass bottle, left in a thermostat at 80 ° C. for 10 days, taken out of the thermostat, and the color tone of each powder was visually observed. As a result, as shown in Table 1, all of the antibacterial compositions of the present invention showed almost no difference in color tone as compared with the sample stored at room temperature. Yellow to yellowish brown discoloration was observed. This means that the composition of the present invention, even if left under severe temperature conditions for a long time,
It means that it is extremely stable in quality. Test Example 2 (Discoloration test of antibacterial composition under immersion in alkaline water) Using the same antibacterial composition sample of the present invention as in Test Example 1, 1 g of each sample powder was weighed in 10 g of 10% NaOH in a bottle. And the color of the powder was observed after 5 minutes.
For comparison, the same test was carried out for the case where the compound containing no imide hydrogen was not contained (Comparative product 1) and for three types of commercially available inorganic antibacterial agents. The results are shown in Table 2. In the case of the antibacterial composition of the present invention, the white color was the same as that immediately before the injection, but all the control products changed from gray to black gray. This test is an important indicator for predicting not only the antibacterial agent itself, but also the overall chemical resistance of the resin mixed with the antibacterial agent, as well as the alkali resistance. This confirms the significance of the antimicrobial composition of the present invention that was not found. Test Example 3 (Evaluation of colorability during kneading and molding into PP resin) 1 part by weight of each antibacterial composition obtained in Example 1 and 0.1 part by weight of hydrotalcite (DHT4A-2 manufactured by Kyowa Chemical Industry Co., Ltd.) Was mixed with 100 parts by weight of PP resin powder (J-707Z manufactured by Grand Polymer Co., Ltd.).
Injection molding (IS-EPN type manufactured by Toshiba Machine Co., Ltd.) at ℃ to obtain a sample plate (sample plate size is 50
× 90 × 5mm), the color tone of which was measured by Minolta spectrophotometer C
The color was measured by M-2022, and evaluated by ΔE value with a molded product made only of the PP resin powder. The results are as shown in Table 3. In the case of the antibacterial composition of the present invention, the ΔE value was 2 or less in all cases, and almost no difference in color tone from the molded product made of PP resin powder alone was observed with the naked eye. On the other hand, Δ
When the E value was 3 or more, a yellowing tendency was more or less visually observed. Also, various antibacterial compositions having passed the discoloration test of Example 1 were kneaded with the PP resin powder in the same manner as above to obtain sample plates, but in the case of the sample plates according to the antibacterial composition of the present invention, Again, almost no yellowing tendency was observed. On the other hand, in the case of the sample plates obtained from the control products having undergone the discoloration test, the yellowing tendency described in Table 3 was further promoted, respectively. This suggests the importance of suppressing discoloration during storage of the inorganic antibacterial material carrying metal ions, and supports the significance of the antibacterial composition of the present invention. Test Example 4 (Light discoloration test of kneaded resin) The light discoloration resistance test of the resin after kneading was performed by the following method. Approximately half of each sample plate was covered with aluminum wheels in three layers and left outdoors in a sunny place. One month later, when the aluminum wheel of each sample plate was removed and the color tone was confirmed, as shown in Table 3, the sample plate according to the antibacterial composition of the present invention did not show any change in color tone so that the boundary could not be seen. In the case of the products, the boundaries were clear, and the parts that were not covered with the aluminum wheels looked considerably darker than the parts that were covered with the aluminum wheels. Test Example 5 (Discoloration test of kneaded PP resin under hot water immersion) Each sample plate obtained in the manner described in Test Example 4 was immersed in hot water of 60 ° C, taken out of hot water after 10 days,
The color tone after drying was measured, and the ΔE value before and after immersion in hot water was calculated to evaluate the degree of discoloration. The results are shown in Table 3, as shown in Table 3, in the case of the sample plate according to the antibacterial composition of the present invention, the ΔE value was 3 or less, which was almost the same as the color tone before the hot water immersion test. In contrast, in the case of the control product, the ΔE value was 10 or more, and yellowish browning was clearly recognized even with the naked eye. Test Example 6 (Antibacterial property test of kneaded PP resin) The following antibacterial property test was performed on each sample plate obtained in the manner described in Test Example 4. As a test strain,
E. coli (IFO-3972) and Staphylococcus aureus (I
FO-12732) was used. For the preparation of the bacterial solution, each test strain cultured on an agar medium at 37 ° C. for 18 hours was used.
A suspension was prepared by suspending the suspension in a phosphate buffer (pH 7.2) and then diluted to prepare a test bacterial solution. (E. coli and Staphylococcus aureus each had an initial cell count of 5.6 × 1
0 ⁵ / ml and 5.3 x 10 ⁵ / ml. As shown in Table 3, the antibacterial evaluation results show that the number of viable bacteria was 1 in the case of the sample plate relating to the antibacterial composition of the present invention.
When it was 0 or less, the antibacterial property was sufficiently maintained. Test Example 7 (Applicability test to resins other than PP resin) As a resin other than the PP resin, an ABS resin (Taflex 410, manufactured by Monsanto) and a polyamide resin (6ND, manufactured by Kanebo) were used. Sample No3
The applicability of the antimicrobial composition was evaluated from various points. The results are shown in Table 4, and the antibacterial composition of the present invention shows A
When mixed with any of the BS resin or polyamide resin, not only does it have no resin coloring during molding,
It was confirmed that there was almost no subsequent discoloration.

[0015]

Industrial Applicability The inorganic antibacterial composition of the present invention does not discolor itself even under severe conditions, and
When it is used by mixing it in a resin, it imparts sufficient antibacterial properties to the resin, and there is no coloring of the antibacterial resin at the time of molding, and even after molding, even under the influence of heat and light over time Almost no discoloration occurred. The outstanding chemical resistance of the inorganic antibacterial composition of the present invention indicates great suitability for fields such as toilet seats, cutting boards and bathtubs, which are difficult with conventional inorganic antibacterial agents. The compound having the present imide hydrogen compounded in the antibacterial composition has a high activity of the imide hydrogen in the ring and a strong ability to substitute a metal ion, so that the inorganic compound carrying the antibacterial metal ion It acts as a collector for excess free metal ions. And the compound having this imide hydrogen is not only in powder form such as an inorganic antibacterial agent,
Even when dispersed in a liquid such as a molten polymer or in a solid such as a resin, it has a great feature in that it acts as a collecting agent for released excess metal ions.
At this time, the complex compound of the present imide hydrogen-bearing compound and free metal ions is not only nearly colorless, but also has a strong ability to form a film on inorganic compounds carrying antibacterial metal ions and suppresses the release of metal ions. Things.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI A01N 59/16 A01N 59/16 A C08K 3/34 C08K 3/34

Claims (2)

[Claims] 1. An antibacterial composition comprising an inorganic compound carrying an antibacterial metal ion and a cyclic compound having imido hydrogen or a substituted product thereof. 2. The antibacterial composition according to claim 1, wherein the inorganic compound supporting the antibacterial metal ion is zeolite.