JPH05148116A - Antibacterial mildew-proofing composition and its production - Google Patents

Abstract

PURPOSE:To obtain an antibacterial mildew-proofing composition containing antibacterial metal in stabilized form, resistant to discoloration and having excellent heat-resistance and stability by adding an aluminum compound as a stabilizer to an antibacterial mildew-proofing composition obtained by adding an antibacterial metal component to calcium phosphate. CONSTITUTION:Calcium phosphate is synthesized by a wet process comprising the dropping of phosphoric acid to a suspension of calcium hydroxide. The objective antibacterial mildew-proofing composition can be produced by adding an antibacterial metal compound (e.g. silver nitrate) and a water-soluble aluminum compound (e.g. aluminum nitrate) to the calcium phosphate. Concretely, a water-soluble salt of aluminum is added simultaneously with the addition of a water-soluble metal compound in the wet-synthesis of calcium phosphate to substitute for a part of Ca ions in the calcium phosphate with the antibacterial metal ion and Al ion. The antibacterial metal ion can be included in a structure of calcium phosphate in a stable state.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an antibacterial / antifungal composition and a method for producing the same, more specifically,
Antibacterial and antifungal composition that stabilizes the antibacterial metal in the antibacterial and antifungal composition by adding antibacterial metal to calcium phosphate, does not discolor, has excellent heat resistance and stability, and has excellent antibacterial and antifungal power The present invention relates to a product and its manufacturing method.

[0002]

2. Description of the Related Art It has been conventionally known that silver, copper, zinc and metal ions thereof have an antibacterial activity, and an antibacterial / antifungal material carrying or exchanging these metal ions on an inorganic compound is known. Proposed. Among these antibacterial metal ions, silver ions are particularly excellent in antibacterial and antifungal properties, and it is said that addition of silver ions markedly improves antibacterial and antifungal properties.

[0003]

However, an inorganic antibacterial / antifungal material containing silver ions is not suitable for the inorganic antibacterial / antifungal agent because ionic silver is unstable under ultraviolet rays and heating and is easily reduced to silver. It has a drawback that the color of the mold material changes to light black or gray. Therefore, a product with antibacterial and antifungal properties coated and impregnated with an antibacterial and antifungal material containing silver ions discolors after being exposed to light or heat and impairs the aesthetics of the product. There was a problem. In addition, the conventional inorganic antibacterial / antifungal material has a problem that the added silver ions are easily eluted from the inorganic material and the antibacterial / antifungal power is gradually decreased, resulting in poor durability. As described above, the problems with the conventional inorganic antibacterial / antifungal materials are a decrease in antibacterial / antifungal ability due to elution of antibacterial metal over a long period of time and discoloration due to ultraviolet rays or heat treatment.

The present invention has been made in view of the above problems, and it is possible to easily add and mix it with other substances to produce an antibacterial / antifungal product, and to maintain antibacterial / antifungal properties for a long period of time. It is an object of the present invention to provide an antibacterial / antifungal composition that does not discolor even by heat processing or UV irradiation.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in view of the problems of conventional antibacterial and antifungal materials, a water-soluble metal compound having antibacterial properties when synthesizing calcium phosphate by a wet method. At the same time as adding a water-soluble salt of aluminum, by replacing a part of Ca ions in calcium phosphate with antibacterial metal ions and aluminum ions, the antibacterial metal ions can be stably incorporated into the calcium phosphate structure. The inventors have found that the above can be achieved and have completed the present invention.

That is, the present invention solves the above-mentioned problems by an antibacterial / antifungal composition obtained by adding an antibacterial metal compound and an aluminum compound as a stabilizer to calcium phosphate. As a method of producing the antibacterial / antifungal composition, a method of synthesizing calcium phosphate by a wet method and adding the antibacterial metal compound and the water-soluble aluminum compound at the same time is preferable.

The present invention will be described in detail below. The antibacterial / antifungal composition according to the present invention comprises calcium phosphate,
An antibacterial metal compound and an aluminum compound as a stabilizer are added, and this composition has a structure in which a part of Ca in calcium phosphate is replaced by the antibacterial metal and aluminum.

As the calcium phosphate, various compositions produced by a wet method can be used, but it is particularly preferable that the molar ratio of calcium to phosphorus is 1.50 to 1.67. As the antibacterial metal added to the calcium phosphate, silver, copper, zinc or the like can be used, and silver is particularly preferable. These antibacterial metals are added as water-soluble compounds to calcium phosphate synthesized by a wet method. Antibacterial metal ions such as silver ions are incorporated into calcium phosphate in a state where a part of Ca ions in calcium phosphate is replaced. The aluminum compound is added to calcium phosphate synthesized by a wet method as a water-soluble aluminum compound such as aluminum nitrate, aluminum sulfate and sodium aluminum sulfate. This aluminum ion is also C in calcium phosphate
It is incorporated into calcium phosphate in a state where a part of the a ion is replaced. The added aluminum prevents the antibacterial metal ions from being reduced by ultraviolet rays or heating and is not eluted from the calcium phosphate, and the antibacterial metal ions such as silver ions are allowed to exist in the calcium phosphate without being changed for a long period of time. It is a stabilizer for

To produce the antibacterial / antifungal composition of the present invention, first, calcium phosphate is synthesized by a wet method. The synthesis of calcium phosphate by the wet method can be carried out by adding phosphoric acid dropwise to the calcium hydroxide suspension. At this time, it is possible to change the substitution capacity of the antibacterial metal ion by controlling the pH value in the suspension by dropping phosphoric acid. That is, in the antibacterial / antifungal composition of the present invention, the substitution amount of the antibacterial metal ion is increased by setting the pH during the calcium phosphate synthesis to the range of 4 to 7, and the antibacterial metal compound is added in this pH range. It is preferable to add.

Phosphoric acid was added dropwise to the calcium hydroxide suspension to adjust the pH to a range of 4 to 7 to stop the addition of phosphoric acid, and aged for preferably 30 minutes or more to obtain a precipitate of calcium phosphate. Then, an antibacterial metal compound solution such as silver nitrate and a water-soluble aluminum compound solution such as aluminum nitrate are simultaneously added during the precipitation of calcium phosphate. Then, the desired antibacterial and antifungal composition is obtained by aging, preferably for several hours or more.

The amounts of the antibacterial metal and aluminum added to the calcium phosphate synthetic product can be arbitrarily selected depending on the kind of the antibacterial metal used, the treatment temperature, the concentration of the treatment solution, the pH, etc. When silver is used, the amount is 10% by weight or less, preferably 0.001 to 5% by weight, based on calcium phosphate. If the amount of antibacterial metal added is less than 0.001% by weight, the antibacterial and antifungal properties are inferior, and sufficient antibacterial and antifungal properties cannot be obtained. If it exceeds 5% by weight, the structure of calcium phosphate collapses. This is because replacement cannot be expected.

The synthetic product of the antibacterial / antifungal composition thus obtained is filtered and then thoroughly washed with distilled water,
After completely removing the contaminants other than the substituted antibacterial metal and aluminum, the mixture is dried and, if necessary, pulverized to produce the antibacterial / antifungal composition of the present invention.

The thus obtained antibacterial / antifungal composition is stable without elution of antibacterial metal ions and has no discoloration due to ultraviolet rays or heating. Therefore, it can be mixed with other materials such as plastics and fibers. It can be used or mixed in paint to be used for antibacterial / antifungal coating.

The antibacterial and antifungal composition according to the present invention suppresses elution of antibacterial metal, exhibits antibacterial and antifungal properties for a long period of time, and does not change due to ultraviolet irradiation or heat treatment and stabilizes the material. Can be planned. That is, the antibacterial / antifungal composition of the present invention has a structure in which a part of Ca ions in calcium phosphate is replaced with an antibacterial metal ion and simultaneously stabilized by being replaced with an aluminum ion so that the antibacterial metal is contained in the crystal structure of calcium phosphate. And aluminum are incorporated therein, and therefore, the antibacterial metal is not easily eluted as ions and is stable for a long period of time. In addition, since the antibacterial metal is incorporated together with aluminum in the crystal structure of calcium phosphate, it does not change its structure with respect to ultraviolet rays and heat, and does not discolor even if exposed to sunlight for a long time or heat-treated. ..

[0015]

EXAMPLES The effects of the present invention will be clarified below with reference to examples. Example 1 37 g of calcium hydroxide was suspended in 1 liter of distilled water and the temperature was set to 40 ° C. 80 to this
Phosphoric acid (g / l) was gradually added dropwise, and when the pH of the suspension reached 6, the addition of phosphoric acid was stopped. After aging for 1 hour, 15 ml of an aqueous silver nitrate solution containing 0.1 g / ml of silver was added, and simultaneously 20 ml of an aqueous aluminum nitrate solution containing 0.05 g / ml of aluminum was added. After aging for 3 hours as it was, the precipitate was filtered and thoroughly washed with distilled water. Collect the precipitate 5
It was dried at 0 ° C. and pulverized to obtain an antibacterial / antifungal composition of the present invention. At this time, the silver content was 1.9% in the powder.

(Comparative Example 1) Silver was prepared in the same manner as in Example 1.
Although 15 ml of an aqueous silver nitrate solution containing 0.1 g / ml was added, aluminum was not added, and an antibacterial / antifungal composition was obtained in the same manner as in Example 1 below. At this time, the content of silver in the powder is 2.3.
%Met.

(Comparative Example 2) To 100 g of a commercially available Na-A zeolite powder, about 50 ml of an aqueous silver nitrate solution containing 0.1 g / ml of silver and distilled water were added to make a total amount of 300 ml. After aging for 15 hours, the silver-substituted zeolite was filtered and thoroughly washed with distilled water.
It dried at 50 degreeC for 20 hours, and obtained Ag substituted zeolite.
At this time, the content of silver in the powder was 2.1%.

Experiment 1 UV resistance The antibacterial and antifungal compositions obtained in Example 1 and Comparative Examples 1 and 2 were irradiated with UV of 254 nm to examine the color change of each composition. The results are shown in Table 1.

[0019]

[Table 1]

As is clear from Table 1, the antibacterial agent of the present invention
The antifungal composition did not undergo discoloration even after being irradiated with ultraviolet rays for 5 hours, and remained white.

Experiment 2 Heat Stability The antibacterial and antifungal compositions obtained in Example 1 and Comparative Examples 1 and 2 were heat-treated in the range of 200 ° C. to 600 ° C. to examine the change in color. As a result, as shown in Table 2, the antibacterial / antifungal composition of the present invention did not undergo discoloration at any temperature treatment and remained white.

[0022]

[Table 2]

Experiment 3 Stability of Antibacterial Activity The antibacterial properties of 1 g of the antibacterial and antifungal compositions obtained in Example 1 and Comparative Examples 1 and 2 were examined after washing with 10 liters of distilled water. Staphylococcus aureus, Bacillus subtilis, Escherichia coli,
Salmonella, Klebsiella pneumoniae, and Pseudomonas aeruginosa were used. Each test bacterium was cultured in a normal broth medium for 24 hours, diluted 100 times, and 0.1 ml of each was inoculated on a regular agar medium.
The test substance was placed on the agar medium inoculated with the bacterium, and after culturing for 48 hours, the width of the inhibition zone formed around the test substance was measured. The results are shown in Table 3. The numerical values in Table 3 are shown by setting the width of the inhibition zone of the unwashed compositions of Example 1 and Comparative Examples 1 and 2 to 1.00 and the width of the inhibition zone after washing as its relative value. ..

[0024]

[Table 3]

As is clear from Table 3, the antibacterial agent of the present invention
It has been confirmed that the antifungal composition has sufficient antibacterial activity even after being thoroughly washed, and has excellent durability.

[0026]

As described above, the antibacterial and antifungal composition of the present invention suppresses elution of antibacterial metal, exhibits antibacterial and antifungal properties for a long period of time, and changes by ultraviolet irradiation and heat treatment. It is possible to stabilize the material without causing That is, the antibacterial / antifungal composition of the present invention has a structure in which a part of Ca ions in calcium phosphate is replaced with an antibacterial metal ion and simultaneously stabilized by being replaced with an aluminum ion so that the antibacterial metal is contained in the crystal structure of calcium phosphate. And aluminum are incorporated therein, and therefore, the antibacterial metal is not easily eluted as ions and is stable for a long period of time. Also,
Since the antibacterial metal is incorporated in the structure together with aluminum, the structure does not change even when exposed to ultraviolet rays or heat, and does not change color even when exposed to sunlight for a long period of time or subjected to heat treatment.

Claims (2)

[Claims] 1. An antibacterial / antifungal composition comprising an antibacterial metal compound and an aluminum compound as a stabilizer, which are added to calcium phosphate. 2. A method for producing an antibacterial / antifungal composition, which comprises synthesizing calcium phosphate by a wet method and simultaneously adding an antibacterial metal compound and a water-soluble aluminum compound thereto.