JP2780877B2 - Paint composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating composition, and more particularly to a coating composition having antibacterial and antifungal properties.

[0002]

2. Description of the Related Art Conventionally, as a coating composition for preventing the growth of bacteria and fungi, there have been known coating compositions containing various preservatives and fungicides. Since such preservatives and fungicides have been pointed out as toxic to the human body,
Organometallic materials such as organic mercury agents are no longer used,
At present, organic chlorine-based and organic sulfur-based preservatives and fungicides, and organic fungicides such as salicylanilide are used.

[0003]

However, the coating composition containing the above-mentioned antiseptic or antifungal agent has a problem that a sufficient antiseptic or antifungal effect cannot be obtained. ing.

[0004] Further, these conventional examples cannot be said to be sufficiently satisfactory in low toxicity and cannot be used in places where the frequency of contact with the human body is high or where foods are handled. there were.

The present invention has been made in view of such problems, and an object thereof is to obtain a coating composition having high safety and sufficient antibacterial and antifungal properties.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a coating composition containing an apatite-based ceramic carrying antibacterial metal ions. As ceramics, in particular, the general formula Ca ₁₀ (M · PO ₄ ) ₆ (OH) ₂
Apatite supporting the antibacterial metal (M) represented by

As the antibacterial metal (M), silver (Ag) is mainly used, and copper (Cu) and zinc (Zn) are also used.
And the like.

[0008] The apatite-based ceramics having antibacterial properties carry an antibacterial metal and are chemically and physically stable and have heat resistance.

Further, such an apatite-based ceramic is made to coexist with an antibacterial metal salt at the time of synthesis.
Alternatively, it can be easily produced by reacting a metal salt. That is, Na ₂ HPO ₄ and an antibacterial metal salt, ie, silver,
While stirring an aqueous solution containing metal salts such as copper and zinc, an aqueous solution of calcium chloride is added dropwise to synthesize apatite by a conventional method, and the product is thoroughly washed with distilled water and dried and pulverized to obtain an antibacterial apatite. Alternatively, the apatite fine powder obtained by a conventional method is suspended in distilled water, a water-soluble antibacterial metal salt is added, and the mixture is stirred, and the product is washed with distilled water, dried and pulverized to obtain the desired product. In these operations, in addition to the supported metal ions, acidic roots and metal salts, and calcium salts generated when the metal ions were replaced with Ca ions, etc., were likely to remain in the antibacterial apatite. It is necessary to thoroughly wash the antibacterial apatite with water to completely remove these contaminants. The amount of the antibacterial metal supported on the antibacterial apatite can be arbitrarily selected depending on the kind of the antibacterial metal salt used, the concentration of the treatment solution, the temperature, etc., but the antibacterial property of the reaction product depends on the amount of the metal salt. Because the structure of apatite may deviate from the apatite structure,
The amount of the metal salt is 30% or less, preferably about 5 to 0.0001% based on apatite.

[0010] The antibacterial apatite thus obtained retains antibacterial properties for a long period of time, and the amount of metal eluted in water is as small as several ppb or less.

[0011]

EXAMPLES The details of the coating composition according to the present invention will be described below based on examples. In the examples, the compositions are shown in parts by weight. In the examples, the chemical formula Ca
Silver (Ag) represented by ₁₀ (Ag · PO ₄ ) ₆ (OH) ₂
Is used.

-Examples- Perlite 20.0 Activated clay 10.0 Titanium white 2.0 Nonionic surfactant 3.0 Alkyd resin 8.5 Toluene 17.0 Casein 2.0 Water 36.0 Apatite (silver) 5.0 The paint having the composition of the above example and the paint of the comparative example containing no apatite (silver) in the composition of the above example were applied to a wooden wall for testing, and the paint was applied in an environment having normal humidity. As a result of standing for a month, no mold was generated on the paint-coated surface of the present example, but mold was found to grow on the coated surface of the comparative example.

In the above examples, apatite (silver) was blended at 5.0% by weight, but it was found that if it was blended in the range of 1 to 20% by weight, antibacterial and antifungal properties were exhibited.

The antibacterial test and antifungal test of only antibacterial apatite showed antibacterial and antifungal properties as shown below.

<Antibacterial activity test> [0015] A test method is as follows. A binder is added to antibacterial apatite (silver), compression molded, degreased at 500 ° C, and a pellet having a diameter of 3 cm, which is 100% of the antibacterial apatite, is prepared. Escherichia coli was adhered to the pellet, and changes in elapsed time and viable cell count were examined. As a result, antibacterial properties as shown in the table below were exhibited.

[0016]

[Table 1]

<Anti-Mold Test> In the test method, a test pellet was placed on an agar medium, and a mold spore suspension was inoculated to examine the growth of the mold.

A. Culture Medium 39 g of potato dextrose (manufactured by Nissui Pharmaceutical Co., Ltd.) agar is dissolved at a ratio of 1,000 ml of purified water, and sterilized by autoclaving at 121 ° C. for 15 minutes. Next, the sterilized medium is poured into a sterile petri dish to prepare a plate agar medium, which is used for the test.

B. Mold Spore Suspension The pre-cultured mold is suspended in a 0.005% dioctyl sodium sulfosuccinate solution. The suspension is then filtered on filter paper and used as a mold spore suspension.

-Strains used Aspergillus, Terreus, Penicillium, Funiculosum were mixed, Cladosporium, Cladosporioides, Ketomium, and Globosum.

C. Test piece pellet Add anti-bacterial water to antibacterial apatite (silver), put in a mold having a diameter of 3 cm and mold. Next, after drying, high-pressure steam sterilization is used.

As a comparative example, hydroxyapatite also produces similar pellets.

D. Test Method The test sample pellet is placed on an agar medium, and the mold spore suspension is applied. In this way, the cells are cultured at a temperature of 25 ° C. and a saturation humidity for 2 weeks.

E. Results No mold growth was observed on the antibacterial apatite (silver) pellets. Mold growth was observed on the entire surface of the hydroxyapatite pellets of the comparative example.

The antibacterial test and the antifungal test have been described above. Next, a test was conducted to determine the elution amount of metals of apatite supporting silver as an antibacterial metal and apatite supporting zinc (Zn) as an antibacterial metal. Is described.

In this test, 1 g of each antibacterial apatite was placed in 100 cc of distilled water, and the concentration of dissolved metal in an aqueous solution stirred for a long time was measured. As a result, in the case of the apatite supporting silver, the content was 0.01 ppm or less, almost no elution was observed, and no increase in the concentration was observed even after a lapse of time. This is presumably because the antibacterial metal is incorporated into the pores in the molecular structure of apatite, and a bond having a stronger binding force than an ionic bond exists. Therefore, it is considered that the compound has stability as a molecule.

The above embodiment is an example of the present invention.
The present invention is not limited to this, and various composition changes accompanying the gist of the configuration can be appropriately made.

[0028]

As apparent from the above description, the coating composition according to the present invention has sufficient antibacterial and antifungal properties, and also has the effect of having stability and safety.

Claims (1)

(57) [Claims] 1. A coating composition comprising a powder of an apatite ceramic carrying antimicrobial metal ions.