JPH04273803A - Antimicrobial agent - Google Patents

Abstract

PURPOSE:To obtain an antimicrobial agent capable of exhibiting antifungal, antimicrobial and antialgal properties for a long period without deteriorating the antimicrobial properties even in severe environment such as exposure to sunrays or a high-temperature atmosphere or contact with an acidic solution. CONSTITUTION:An antimicrobial agent composed of a specific phosphate-based compound represented by a compound expressed by the following general formula. AgaAbM<2>c(PO4)d.nH2O [A is at least one metallic ion selected from alkali metallic ions, etc.; M<2> is tetravalent metal; (n) is a number satisfying 0<=n<=6; both (a) and (b) are positive numbers; (c) and (d) are as follows; when (a+mb) is 1; (c) is 2 and (d) is 3; when (a+mb) is 2, (c) is 1 and (d) is 2, provided that (m) is the valence of A].

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides antifungal, antibacterial and antialgal properties of silver, copper, zinc, tin, mercury, lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, cadmium, chromium, etc. This relates to an antibacterial agent made of a specific phosphate-based compound that has metal ions that exhibit properties, and can be used as an antibacterial composition mixed with various binders, or supported on a carrier such as fiber, film, paper, or plastic. It can be used as an antibacterial molded product.

0002

[Prior Art] Silver, copper, zinc, tin, mercury, lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, chromium, etc. exhibit antifungal, antibacterial, and antialgal properties. Silver has long been known as a metal (hereinafter abbreviated as antibacterial metal), and in particular, silver is widely used as an aqueous solution of silver nitrate, which has disinfectant and bactericidal effects. However, the above-mentioned metal ions that exhibit antifungal, antibacterial, and antialgal properties are often toxic to the human body.
There were various restrictions on how to use, how to preserve, how to dispose of, etc., and the applications were also limited.

[0003] In recent years, it has become clear that it is sufficient to have a trace amount of antibacterial metal act on the target in order to exhibit antifungal, antibacterial, and antialgal properties. As an antibacterial agent with algal properties, an organic antibacterial agent in which an antibacterial metal is supported on an ion exchange resin or a chelate resin;
Also, inorganic antibacterial agents have been proposed in which antibacterial metals are supported on clay minerals, inorganic ion exchangers, or porous materials.

Among the various antibacterial agents mentioned above, inorganic antibacterial agents are generally safer than organic ones, have a long-lasting antibacterial effect, and have excellent heat resistance. One of the inorganic antibacterial agents is an antibacterial agent that is made by ion-exchanging silver ions with alkali metal ions such as sodium ions in clay minerals such as montmorillonite and zeolite, but this is because the skeleton structure of the clay mineral itself is acid-resistant. For example, silver ions are easily eluted in acidic solutions, and the antibacterial effect is not sustainable. Furthermore, silver ions are unstable when exposed to heat and light, and are quickly reduced to metallic silver, resulting in coloring and lack of long-term stability.

[0005]Also, in order to increase the stability of silver ions, there is a product in which silver ions and ammonium ions are co-supported on zeolite through ion exchange, but prevention of coloration has not reached a practical level and no fundamental solution has been found. This has not yet been achieved. Furthermore, as other inorganic antibacterial agents, there are antibacterial agents in which antibacterial metals are supported on activated carbon, which has adsorption properties, but because soluble antibacterial metal salts are physically adsorbed or attached to them, When it comes into contact with moisture, the antibacterial metal ions are rapidly eluted, and the antibacterial effect is not sustainable.

[0006]

[Problems to be solved by the present invention] The present invention has the ability to maintain its antibacterial properties for a long time without deteriorating even in harsh environments such as exposure to sunlight, high-temperature atmospheres, or contact with acidic solutions. It is an object of the present invention to provide a material that can exhibit anti-algae properties.

[0007]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors have discovered that a specific phosphate compound containing antibacterial metal ions has extremely excellent chemical and It was discovered that it has physical stability and long-term fungicidal, antibacterial, and algaeproofing properties, leading to the completion of the present invention. That is, the present invention relates to an antibacterial agent comprising a compound represented by the following general formula [1]. M1aAbM2c(PO4)d・nH2O
[1] (M1 is silver, copper, zinc, tin, mercury,
At least one metal ion selected from lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, or chromium, and A is selected from an alkali metal ion, an alkaline earth metal ion, or an ammonium ion. At least one kind of metal ion, M2 is a tetravalent metal, n is a number satisfying 0≦n≦6, a and b are both positive numbers, and c and d are when la+mb=1. , c=2, d=3, la+mb
When =2, c=1 and d=2. However, l is the valence of M1, and m is the valence of A. )

[0008] The compounds used in the present invention and their methods of use will be explained below. ○Phosphate Compound The compound used in the present invention is a compound represented by the following general formula [1]. M1aAbM2c(PO4)d・nH2O
[1] (M1 is silver, copper, zinc, tin, mercury,
At least one metal ion selected from lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, or chromium, and A is selected from an alkali metal ion, an alkaline earth metal ion, or an ammonium ion. At least one kind of metal ion, M2 is a tetravalent metal, n is a number satisfying 0≦n≦6, a and b are both positive numbers, and c and d are when la+mb=1. , c=2, d=3, la+mb
When =2, c=1 and d=2. However, l is the valence of M1, and m is the valence of A. )

The compound represented by the above general formula [1] is l
When a+mb=1, it has coefficients of c=2 and d=3,
It is an amorphous or crystalline compound belonging to space group R3c, and each constituent ion represents a compound forming a three-dimensional network structure, and when la+mb=2, it has coefficients of c=1 and d=2. Represents a compound whose constituent ions form a layered structure. Phosphate compounds used in the present invention are suitable for l
A crystalline compound having an amorphous or three-dimensional network structure with coefficients a+mb=1, c=2, and d=3 is preferred.

M1 in the above general formula [1] is a metal known to exhibit antifungal, antibacterial, and antialgal properties. Among these, silver is known for its antifungal, antibacterial, and antialgal properties.
It is particularly effective as a metal that can enhance antibacterial and antialgal properties.

A in the above general formula [1] is an alkali metal ion, an alkaline earth metal ion or an ammonium ion. Preferred specific examples include alkali metal ions such as lithium, sodium and potassium, magnesium or calcium, etc. There are alkaline earth metal ions, and among these, lithium ions, sodium ions, and ammonium ions are preferred from the standpoint of compound stability and low cost availability.

M2 in the above general formula [1] is a tetravalent metal, and preferred specific examples include zirconium, titanium, and tin. Considering the safety of the compound, zirconium and titanium are particularly preferred as tetravalent metals. It is metal.

Specific examples of the phosphate compounds represented by the above general formula [1] include the following. Ag0.005Li0.995Zr2(PO4)3Ag
0.01(NH4)0.99Zr2(PO4)3Ag0
．． 05Na0.95Zr2(PO4)3Ag0.2K0
．． 8Ti2(PO4)3 and Ag in each of the above formulas are replaced by Zn, Mn, Ni, Pb, Hg, S
n, or a compound substituted with Cu, Ag0.001Li1.999Zr(PO4)2Ag0
．． 01Na1.99Zr(PO4)2Ag0.01K1
．． 99Sn(PO4)2・1.2H2OAg0.1(N
H4)1.9Ti(PO4)2.4H2O and compound 1
Ag in each of the above formulas is replaced by Zn, Mn, Ni, while making sure that the charge amount is the same as the charge amount of silver ions per mole.
, Pb, Hg, Sn, or Cu.

Methods for synthesizing the phosphate compound used in the present invention include a calcination method, a wet method, and a hydrothermal method. For example, it can be easily obtained as follows.・Synthesis of network structure phosphate When synthesized by the firing method, lithium carbonate (Li2CO
3) Or compounds containing alkali metals such as sodium carbonate (Na2CO3), zirconium oxide (ZrO2)
A zirconium-containing compound such as zirconium-containing compound and a phosphoric acid group-containing compound such as ammonium dihydrogen phosphate (NH4H2PO4) are mixed in a molar ratio of approximately 1:4:6, and the mixture is heated at 1100 to 1400°C. By firing,
General formula [2] Ax Zr2(PO4)3
[2] (A has the same meaning as above, x is 1 when A is monovalent, and when A is 2
(When the value is 1/2), a compound is obtained. By immersing this in an aqueous solution containing silver ions at an appropriate concentration at room temperature to 100°C, a compound represented by general formula [1] is obtained. When synthesizing by a wet method, oxalic acid is added to an aqueous solution of zirconium oxynitrate and sodium nitrate while stirring, and then phosphoric acid is added thereto. The pH of the reaction solution was adjusted to 3.5 with an aqueous caustic soda solution, and after heating under reflux for 78 hours, the precipitate was filtered, washed with water, dried, and pulverized to obtain reticulated zirconium phosphate [NaZr2(PO4)3]. By immersing this in an aqueous solution containing an antibacterial metal at an appropriate concentration, a compound represented by the general formula [1] is obtained.

・Synthesis of layered structure phosphate An oxychloride containing a tetravalent metal such as zirconium oxychloride, titanium oxychloride or tin oxychloride, titanium or tin as a constituent element in a concentrated aqueous phosphoric acid solution. After heating and refluxing for 24 hours, the precipitate was filtered, washed with water, dried,
Grind, zirconium phosphate [Zr(HPO4)2.H
By obtaining a phosphate such as [2O], adding it to an aqueous solution of a nitrate such as an alkali metal, stirring, washing with water, drying and pulverizing, the general formula [3] A2xZr(PO4)2・nH2O [
3] (A, x and n have the same meanings as above) is obtained. By immersing this in an aqueous solution containing an antibacterial metal at an appropriate concentration, a compound represented by the general formula [1] is obtained.

The value of a in general formula [1] is the concentration of silver in the aqueous solution in which the compound represented by general formula [2] or [3] is immersed, and the value of a in general formula [2] or [3] is determined by the concentration of silver in the aqueous solution in which the compound represented by general formula [2] or [3] is immersed. By adjusting the time or temperature at which the compound represented by 3) is immersed, it can be adjusted as appropriate depending on the required characteristics, usage conditions, etc.

[0017] In order to exhibit antifungal, antibacterial, and antialgal properties, the value of a in general formula [1] should be large, but
If the value of a is 0.001 or more, the antifungal, antibacterial, and antialgal properties can be sufficiently exhibited. However, if the value of a is less than 0.001, it may be difficult to exhibit the antifungal, antibacterial, and antialgal properties for a long time, so the value of a is set to be 0.01 or more. It is preferable. Furthermore, in consideration of economic efficiency, the value of a is suitably 0.5 or less.

The phosphate salts used in the present invention are stable to heat and light exposure, at temperatures as high as 500°C and, in some cases, 88°C.
The structure and composition do not change at all even after heating at 00°C to 1100°C, and no discoloration occurs even when irradiated with ultraviolet rays. Furthermore, no change in the skeletal structure is observed even in acidic solutions. Therefore, it is not subject to restrictions such as heating temperature or light shielding conditions during processing and storage when obtaining various molded products, and when used, unlike conventional antibacterial agents.

[0019] There are no particular restrictions on the form in which the antibacterial agent of the present invention can be used, and it can be mixed with other components or composited with other materials as appropriate depending on the application. For example, it can be used in various forms such as powder, powder-containing dispersion, powder-containing particles, powder-containing paint, powder-containing fiber, powder-containing paper, powder-containing film, powder-containing aerosol, etc. It can also be used in combination with various additives or materials such as odorants, flame retardants, anticorrosion agents, fertilizers, and building materials.

The antibacterial agent of the present invention exhibits antifungal, antibacterial, and antialgal properties for any purpose with respect to mold, fungi, and algae on which antibacterial metal ions such as silver ions act effectively. For example, it can be effectively used for the following purposes. Fibers such as work clothes, medical clothes, medical bedding, sports clothes, bandages, fishing nets, curtains, carpets, underwear, air filters; Papers such as wallpaper; Food packaging films, medical films, synthetic leather, etc. Membranes; paints such as sterilizer wall paints, antiseptic paints, and antifungal paints; powders such as agricultural soil; liquid compositions such as shampoos.

[0021]

[Examples] The present invention will now be explained in more detail with reference to Examples. First, a phosphate (a compound corresponding to the above general formula [2] or [3]), which is a raw material for an antibacterial agent, was synthesized.

Reference Example 1 (Preparation of network phosphate) Lithium carbonate, zirconium oxide and ammonium dihydrogen phosphate were charged in a molar ratio of 1:4:6, mixed thoroughly, and heated to 1300°C. LiZr2(PO4
) A compound having the composition formula 3 was obtained. Furthermore, by adding the obtained powder to an aqueous sodium and potassium nitrate solution, stirring, washing with water, drying, and pulverizing, NaZ
r2(PO4)3 and KZr2(PO4)3 were obtained. Further, a compound having the composition formula LiTi2(PO4)3 was obtained in the same manner as above except that titanium oxide was used in place of zirconium oxide.

Reference Example 2 (Preparation of layered phosphate) Zirconium oxychloride was added to a concentrated aqueous phosphate solution, and 2
After heating under reflux for 4 hours, the precipitate was filtered, washed with water, dried and pulverized to obtain zirconium phosphate H2Zr(PO4)2.H2O. By adding this to a nitric acid aqueous solution of sodium and potassium, stirring, washing with water, drying and pulverizing,
Na2Zr(PO4)2 and K2Zr(PO4)2 were obtained.

Example 1 (Preparation of antibacterial agent) Using the powders of various phosphates prepared in Reference Examples, antibacterial agents were prepared by the method shown below. That is, the powder obtained in the reference example was added to an aqueous solution of antibacterial metal nitrate having various concentrations.
Stir for hours. Thereafter, these slurries were filtered and thoroughly washed with pure water. Furthermore, the target antibacterial agent was obtained by heating and drying at 110° C. overnight.

Comparative Example 1 (Preparation of antibacterial zeolite) Type A zeolite (composition: 0.94Na2O.Al2O3.1
．． 92SiO2.xH2O*) was added to silver nitrate alone or to an aqueous solution of silver nitrate and ammonium nitrate, stirred at room temperature for 5 hours, thoroughly washed with water, and dried at 110°C to obtain antibacterial zeolite. Table 1 shows the antibacterial agents prepared by the above method.

[0026]

[Table 1] Note) Sample No. Samples No. 1 to 6 were obtained by the method of Example 1, and Sample No. 7-8 are comparative example 1
Sample No. 9 is
Sample No. It is a raw material of No. 1, and is a zirconium phosphate salt that is not immersed in an aqueous nitric acid solution of an antibacterial metal.

Example 2 (Evaluation of antibacterial activity) The antibacterial activity of the antibacterial agent prepared in Reference Example was evaluated based on the minimum concentration of the antibacterial agent that was able to inhibit the growth of the specimen under the following culture conditions. ○Test bacteria: Escherichia coli and Pseudomonas aeruginosa Yeast: Candeda yeast Mold: Aspergillus oryzae ○Cultivation conditions for the test sample Bacterial solution for inoculation is smeared with a nichrome wire loop (approximately 1 mm in inner diameter) on a plate for susceptibility measurement to a width of about 2 cm. , 37℃ for 18-20 hours for bacteria, 25℃ for mold.
The cells were cultured at ℃ for 7 days. ○ Preparation of bacterial solution for inoculation For bacteria: Inoculate the subcultured test bacterial strain into an enrichment medium,
After culturing, the mixture was diluted with an enrichment medium so that the number of bacteria was approximately 10 6 /ml to prepare a bacterial solution for inoculation. For mold: Inoculate the subcultured test bacterial strain into an enrichment medium so that the number of conidia formed after culturing is approximately 106/ml.
The cells were suspended in a sterile 0.05% polysorbate 80 solution to prepare a bacterial solution for inoculation. For yeast: Inoculate the subcultured test strain into an enrichment medium,
After culturing, the cells formed were suspended in sterile physiological saline at a concentration of approximately 10 6 cells/ml to provide an inoculum solution. ○Enrichment medium for bacteria: Muller-Hinton broth (Muller-Hi
For mold: Potato dextrose agar medium For yeast: Yeast Morphology Agar
ogyAgar ) ○ Susceptibility measurement medium for bacteria: Muller Hinton medium (Muller
-Hinton Medium) For mold and yeast: Sabouraud agar medium ○ Preparation of medium for measuring susceptibility After dissolving Mueller Hinton medium or Sabouraud agar medium while heating, add sterile purified water to the medium for measuring susceptibility at 50 to 60°C. Add 1/9 volume of the diluted suspension of each sample to various concentrations to the culture medium for susceptibility measurement, mix thoroughly, dispense into petri dishes, solidify, and add to plate for susceptibility measurement. did. Table 2 shows the evaluation results regarding the antibacterial activity obtained as described above.

[0028]

[Table 2]

Example 3 (Discoloration test) To the various antibacterial agents prepared in the reference examples, 3 wt % of sepiolite as a binder and 5 wt % of titanium oxide or ascorbic acid as a discoloration accelerator were added, and after thorough mixing, tablets were prepared. Tablets with a diameter of 13 mm and a height of 5 mm were molded using a molding machine at a pressure of 200 kg/cm2. The tablets prepared as described above were exposed to sunlight through a window glass for 3 days, and these tablets were tested by Nippon Denshoku Kogyo Co., Ltd.
Using a manufacturing color difference meter SZ-Σ80, the color at the time of molding and the color after exposure to sunlight was measured. Among these colors, sample No. 1 does not contain antibacterial metals. Regarding the tablet No. 9, the color at the time of molding is (Lx1, ax1, bx1),
Color after exposure to sunlight (Lx2, ax2, bx2
), sample No. For tablets other than 9, the color at the time of molding is (Ly1, ay1, by1) and the color after exposure to sunlight is (Ly2, ay2, by2), and the difference in these colors was determined by the following formula.・Sample No. Color difference during molding of tablets other than 9 [
(Ly1-Lx1)2 + (ay1-ax1)2 +(
by1-bx1)2]1/2 ・Sample No. Color difference after exposure to sunlight in tablets other than 9 [(Ly2-Lx1)2 + (ay2-ax1)2 +
(by2-bx1)2]1/2 Note that sample No. The color difference after exposure to sunlight in No. 9 was calculated by the following formula and was 0.8. [(Lx2-Lx1)2 + (ax2-ax1)2 +
(bx2-bx1)2]1/2 Table 3 shows the evaluation results of the discoloration test obtained as described above.

[0030]

[Table 3]

Example 4 (Evaluation of Acid Resistance 1) 10% of the various antibacterial agents prepared in Reference Example were added to a 4% acetic acid aqueous solution (pH 3).
wt% was added and allowed to stand for 4 hours, the antibacterial agent was filtered off, and the amount of elution of various antibacterial metals in the filtrate was measured using an atomic absorption spectrophotometer. Table 4 shows the evaluation results regarding acid resistance obtained as described above.

[0032]

[Table 4]

Example 5 (Evaluation of Acid Resistance 2) Antibacterial paints were prepared by adding 10% of each of the antibacterial agents prepared in Reference Example to acrylic resin paints (solid content 10%) and stirring well. The paint obtained as described above was applied to polyester paper to produce antibacterial treated paper carrying an antibacterial agent at a rate of 0.1 g/m2. The antibacterial treated paper was immersed overnight in a nitric acid aqueous solution with a pH of 2, thoroughly washed with water, and its antibacterial activity was evaluated by the following test method using Escherichia coli as the test bacteria. The number of bacteria per 25 cm2 of antibacterial treated paper is 104 to 10
The bacterial solution was inoculated onto antibacterial treated paper so that 5 cells were collected. After 0 hours (immediately after inoculation) and 24 hours after the antibacterial treated paper inoculated with the bacterial solution was started to be stored at 37°C, the antibacterial treated paper was incubated with a culture medium for bacterial count measurement (SCDLP liquid medium). The bacteria were washed out and the washing liquid was used as the test liquid. This test solution was cultured using a pour plate culture method (37℃2
The number of surviving bacteria was measured by 25 cm of antibacterial treated paper.
It was converted to the number of viable bacteria per . Table 5 shows the evaluation results regarding acid resistance obtained as described above.

[0034]

[Table 5]

Example 6 (Evaluation of Heat Resistance) The various antibacterial agents prepared in Reference Examples were baked at 1000° C. for 4 hours. The antibacterial activity of each of these baked antibacterial agents was evaluated in the same manner as in Example 2. Table 6 shows the evaluation results regarding heat resistance obtained as described above.

[0036]

[Table 6]

[0037]

[Effect of the invention] The antibacterial agent of the present invention does not deteriorate in antibacterial properties even under harsh environments such as exposure to sunlight, high temperature atmosphere, or contact with acidic solutions, and has antifungal, antibacterial, and antialgal properties. It is extremely useful as a material that can exhibit the effects for a long time.

Claims (1)

[Claims] [Claim 1] An antibacterial agent comprising a compound represented by the following general formula [1]. M1aAbM2c(PO4)d・nH2O
[1] (M1 is silver, copper, zinc, tin, mercury, lead,
At least one metal ion selected from iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, or chromium, and A is at least one metal ion selected from an alkali metal ion, an alkaline earth metal ion, or an ammonium ion. is a seed metal ion, M2 is a tetravalent metal, n is a number satisfying 0≦n≦6, a and b are both positive numbers, and c and d are when la+mb=1, c =2, d=3, la+mb=2
When , c=1 and d=2. However, l is the valence of M1, and m is the valence of A. )