JPH03190805A - Antibacterial agent having deodorant property and production thereof - Google Patents

Abstract

PURPOSE:To obtain an antibacterial agent exhibiting persistent antibacterial property with stabilized in an active state and having excellent adsorbing property by making a metal having an antibacterial action to an oxide and making the oxide to an amorphous compound material together with silicon dioxide. CONSTITUTION:The aimed antibacterial agent is composed of an amorphous compound material of an oxide of a metal (especially silver, copper or zinc is preferable) having an antibacterial action and silicon dioxide having many merits in viewpoints of persistence of antibacterial effect, stability of antibacterial substance and heat resistance, etc., and further adsorbing ammonia, amines, hydrogen sulfide or mercaptans, etc. An aqueous solution of a water-soluble salt of metal having an antibacterial action is mixed with an aqueous solution of sodium silicate and reacted, then an amorphous compound slurry composed of a gel-like metal oxide and silicon dioxide is obtained, thus further said two aqueous solutions are independently and gradually added to the slurry with keeping pH at 6.5-8.0 and a generated gel is separated, then dried to afford the aimed antibacterial agent.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a novel antibacterial agent having antibacterial activity against various bacteria and adsorption effect against various bad odors, and a method for producing the same.

<Conventional technology> Conventionally, antibacterial agents have been produced by adsorbing metals such as silver, which have antibacterial effects, or their compounds onto adsorbents such as zeolite, heptadal charcoal, activated alumina, and silica gel for antibacterial and/or adsorption purposes. (This is known to be used. Many other organic substances have also been devised.

<Problem to be solved by the invention> However, simply adsorbing metals and their compounds with antibacterial effects to such conventional adsorbents has problems with stability, antibacterial effects, and sustainability of adsorption effects. It is hard to say that these points are sufficient.

Additionally, organic types have drawbacks such as poor heat resistance and high vapor pressure.

This invention was made in response to these conventional problems, and it stabilizes a metal with antibacterial activity in an active state to have a long-lasting antibacterial effect as well as good adsorption. This was done with the aim of providing an antibacterial agent with high performance.

<Means/effects for solving the problem> In order to achieve the purpose stated in item 2, the inventor has conducted extensive research and found that by converting a metal with antibacterial action into an oxide and an amorphous composite with silicon dioxide. , has many advantages in terms of sustainability of antibacterial effect, stability of antibacterial substances, heat resistance, etc. Furthermore, malodorous gases such as ammonia, amines, hydrogen sulfide, mercaptans, etc. can be absorbed by coordination bonds with metals. It was discovered that chemical adsorption occurs, which led to the present invention.

The above-mentioned amorphous composite of an oxide of a metal having an antibacterial effect and silicon dioxide is produced by mixing and reacting an aqueous solution of a water-soluble salt of a metal with an antibacterial effect with an aqueous solution of sodium silicate, and forming the resulting gel. It can be manufactured by drying. However, the above manufacturing method has the following drawbacks. If the reaction is carried out under conditions with little moisture, the resulting gel will have a significantly high viscosity.
Uniform reaction is difficult to occur.

This tendency increases as the concentration of the raw material aqueous solution increases,
Depending on the conditions, the gel becomes a lumpy solid. in this case,
Gelation begins before the raw material aqueous solution is evenly mixed, and the viscosity rapidly increases, making homogenization difficult. As a result, the performance of the antimicrobial agents produced is less reproducible.

In addition, under low moisture conditions, a homogeneous gel with relatively low viscosity can be obtained, but this gel has poor filterability and has a water content of over 80% after solid-liquid separation, so it takes an extremely long time to filter and dry. It takes.

As a result of further research to solve these drawbacks, the following manufacturing method was invented.

That is, in the production of an antibacterial agent having deodorizing performance according to the present invention, an aqueous solution of a water-soluble salt of a metal having an antibacterial effect and an aqueous solution of sodium silicate are mixed in a reaction system in which the water content is 85%.
% or more and react to prepare a gel-like amorphous composite slurry of metal oxide and silicon dioxide,
Using this slurry as a mother liquor, adjust its pH to 6.5 to 8.0.
While keeping the temperature at
This method is characterized in that the resulting gel is separated and then dried.

According to the method of the present invention, the raw material liquid is added to the mother liquor and diluted, so that the reaction takes place in a substantially uniformly mixed state. In addition, the raw material components are always diluted in the mother liquor (Y
Since the pH of the mother liquor slurry is kept almost constant throughout the reaction, it is possible to obtain a homogeneous gel-like amorphous composite slurry of metal oxide and silicon dioxide.

Moreover, since the gel obtained at this time has a relatively low water content of 50 to 80%, it has good filterability and drying properties.

As the water-soluble salt of a metal having an antibacterial effect as a raw material, silver nitrate, copper nitrate, zinc nitrate, copper sulfate, zinc sulfate, copper chloride, zinc chloride, etc. can be preferably used. On the other hand, water glass, which is industrially produced in large quantities, can be used as the sodium silicate.

When carrying out this manufacturing method, first, an aqueous solution of a water-soluble salt of a metal having antibacterial activity and an aqueous sodium silicate solution are mixed and reacted so that the water content in the reaction system is 85% or more, and the gel is formed. An amorphous composite slurry of metal oxide and silicon dioxide is produced and used as a mother liquor slurry. At this time, if the water content is less than 85%, the viscosity of the slurry will be high and stirring will be difficult.
Not suitable as liquid slurry. Next, while stirring this mother liquor slurry, new aqueous solutions of each raw material are simultaneously and separately gradually added to this slurry. In this way, an amorphous composite of a gel-like metal oxide and silicon dioxide with a moisture content of 50 to 80% and good filterability is formed in the mother liquor.

Furthermore, a portion of the slurry obtained by the simultaneous addition reaction method as described in Section 2 can be taken out and used repeatedly as a mother liquor slurry. The slurry at this time has a significantly reduced viscosity due to the effect of the simultaneous addition reaction, so it is not necessary for the water content to be 85% or more. In subsequent repeated reactions, by setting the pH of the slurry during the reaction to 6.5 to 80, a gel with a water content of 50 to 80% with good filterability can be produced even under conditions where the water content in the system is less than 85%. It is possible to obtain

The gel prepared as described above is filtered, washed with water to remove by-product sodium salts, and then dried at a temperature below 300°C to form an amorphous form of metal oxides and silicon dioxide that have antibacterial properties. An antibacterial agent with deodorizing performance is obtained, which is composed of a composite of. When the drying temperature exceeds 300°C, the specific surface area of the antibacterial agent decreases extremely, and the antibacterial and adsorption power tends to decrease.

The factor that determines the water content of the product of this reaction is primarily the pH of the slurry, which is the reaction mother liquor.

That is, if the pH of the slurry during the reaction is maintained at 6.5 or less, the slurry will have a relatively high viscosity, and the resulting gel will have a high water content and poor filterability.

When the pH is set to 65 to 80, preferably 7.0 to 7.5, the viscosity of the slurry becomes extremely low and a gel with good sedimentation properties is produced. The gel obtained under these conditions has a water content of 50 to 80% and has extremely good filterability. If the pH of the slurry exceeds 80, the water content of the resulting gel will be low, but the deviation from the pH in reaction equivalents will become large, which is not preferable.

Actual adjustment of the pI of such a slurry is possible by slightly varying the ratio of metal salt and sodium silicate additions, i.e., the metal salt is added in somewhat excess over the lithium silicate. If the pH of the slurry is maintained while being supplied to the reaction tank, the pH of the slurry during the reaction will become slightly acidic, and vice versa, it will become alkaline.In actual reaction, the pH of the slurry during the reaction will be slightly alkaline. When equivalent amounts of are reacted, the pH of the resulting slurry will be 65 to 7.5.

Furthermore, during the reaction, if the metal salt is used in an insufficient amount and the excess sodium content is neutralized with an acid, antibacterial agents containing various ratios of metal oxide and silicon dioxide can be prepared.

<Examples> Next, the present invention will be explained in detail with reference to Examples and Comparative Examples. However, the Examples are provided for illustrative purposes only, and the present invention is not limited by these Examples. . It goes without saying that the effects, manufacturing methods, etc. of products obtained by combining other silks selected from silver, copper, and zinc and combinations with other metals are included in the present invention.

In addition, the antibacterial test in the examples was conducted in the following manner.Powder samples were placed in a 300 ml triangular container, and 100 ml of each bacterial solution (E. coli, staphylococcus) was added, followed by shaking at room temperature. The number of bacteria was measured 24 hours later.

In addition, the deodorization test was conducted as follows: Powder sample 0
．． 5g of gas was diluted with nitrogen gas at a specified concentration at 3°C.
It was placed in a sealed Tetra bag. Changes in gas concentration over time were measured using a gas detection tube.

Comparative Example 1 Zinc sulfate ZnS0 ・7H,,01-9,8g in water 5
Dissolved in 0 ml. Meanwhile, add 50 g of water glass No. 3 to 17 g of water.
Diluted with 0 ml. These raw material solutions were mixed to form a gel, which was left to mature at room temperature for 90 minutes. The pH of the gel slurry was 6.8.

200 ml of the gel slurry was suction filtered through a Buchner funnel with a diameter of 108 m and washed 5 times with 100 ml of water. Washing 1
15-20 minutes of filtration time was required per 100 ml of water.

It was dried for 10 hours in a dryer at 200°C to obtain antibacterial agent A. Loss on drying is 88%, specific surface area is 1.85 tn2
It was 7g.

Example 1 200 m of gel slurry prepared in the same manner as Comparative Example 1
1 as a mother liquor in a 3ρ volume beaker, and while stirring the mother liquor at 25 Orpm, 0.67 mol/dm"Zn
S O4 aqueous solution and 0.7 mol/dm Na
202.1 mol/dm S i O, 14 of each aqueous solution were added simultaneously and separately at 5.5 m/min.

The slurry pH during the reaction was 72-7.5. 200 ml of this slurry was filtered in the same manner as in Comparative Example 1, and the resulting gel was washed with water. The filtration time per 100 ml of wash water was 30-40 seconds. After washing the gel, heat it at 110℃ for 2
Those dried at 00°C and 300°C were designated as antibacterial agents B-1, B-2 and B-3, respectively. Drying loss is approximately 75
%, the specific surface areas are 365.19g and 16 respectively.
It was 3m2/g.

1 Comparative Example 2 Example] The gel obtained was washed with water and dried at 500°C to obtain an antibacterial agent C. The specific surface area was 70 m27g.

Example 2 Copper sulfate Cu S 0 ・5 H2045, 3g in water 2
It was dissolved in 50ml. On the other hand, 125 g of water glass No. 3 was diluted with 500 ml of water. These raw material solutions were mixed to produce a gel. 400 ml of this slurry was used as a mother liquor,
0.8 mol/dm Cu S O4 aqueous solution and 0°3 6 mol/dm Na O-1,8 mol/dm S
2ρ of each aqueous solution were added simultaneously and separately at [i, Oml/min] to react. Mother liquor is 350 rpm
The pH during the reaction was 6.8 to 7.2. The resulting gel was filtered, washed with water, and dried at 110° C. for 6 hours to obtain an antibacterial agent. The specific surface area was 340 m2/g.

Example 3 Silver sulfate A g N O 31,,23 tr and 69% nitric acid 1
19g was dissolved in water to make 100ml. On the other hand, 50 g of water glass No. 3 was diluted with 100 ml of water. Two of these raw material solutions were mixed to produce a gel. This was left for 60 minutes at room temperature to age. The gel was filtered, washed with water, and incubated at 110°C for 10
After drying for a while, antibacterial agent E was obtained. Specific surface area is 31.5m2
/g.

Example 4 Silver nitrate AgN0 1.23g Copper nitrate Cu (N O3)
2-3H207,01,g and zinc nitrate Zn(N.

3) 88 g of 2' 6H2011 was dissolved in 1-1-5O of water. On the other hand, 50 g of water glass No. 3 was diluted with 150 ml of water. Thereafter, antibacterial agent F was obtained in the same manner as in Example 3. The specific surface area was 325 d/.

When the antibacterial agents A-F obtained above were examined by powder X-ray diffraction, they were all amorphous (amorphous). Also,
The results of these antibacterial tests are shown in Table 1, and the results of the deodorization test are shown in Table 2.
Shown below. It can be seen that the antibacterial agents B-1, B-2 and B- obtained in Example 1 are deodorizing and antibacterial.
Comparing antibacterial agent C obtained in Comparative Example 2 with 1, it is found that
It can be seen that the performance is extremely low due to drying.

Regarding the manufacturing method, comparing Example 1 with Comparative Example 1,
It can be seen that the manufacturing process is very good.

1'3 4 Table 1 Antibacterial test <Effects of the invention> As explained above, the amorphous composite of a metal oxide and silicon dioxide having an antibacterial effect according to the present invention has the following effects and characteristics. There is.

1. Compared to conventional organic antibacterial agents, the antibacterial agent of the present invention is inorganic, so it is structurally stable, has a low vapor pressure, and has high heat resistance.

2 The antibacterial agent of this invention is poorly soluble in water.

3. Quickly adsorbs and deodorizes malodorous components such as ammonia, hydrogen sulfide, mercaptans, and amines.

4. Raw materials are cheap.

5. Easy to manufacture.

Furthermore, due to the above-mentioned characteristics, the amorphous composite of a metal oxide and silicon dioxide having an antibacterial effect according to the present invention can be used not only as a powder or granule.
By adding it to and processing base materials such as various plastics, paper, and fibers, it is possible to impart antibacterial and deodorizing properties to the base materials, and its range of applications is extremely wide.

With the production method according to the present invention, a homogeneous amorphous composite gel of metal oxide and silicon dioxide can be prepared. Furthermore, since the above-mentioned Kel has good filterability and relatively low water content, it has the advantage that in its industrial production, the filtration and drying steps can be significantly shortened and the process is economical. Also,
It can be applied not only to metals that have antibacterial effects but also to other metals.

Claims (1)

[Scope of Claims] 1. An antibacterial agent having deodorizing properties and consisting of an amorphous composite of a metal oxide having antibacterial action and silicon dioxide. 2. The antibacterial agent having deodorizing performance according to claim 1, wherein the metal having antibacterial action is selected from silver, copper and zinc. 3. An aqueous solution of a water-soluble salt of a metal with antibacterial activity and an aqueous solution of sodium silicate are reacted together so that the water content in the reaction system is 85%.
Amorphous composite slurry of gel-like metal oxide and silicon dioxide is prepared by mixing and reacting so that A method for producing an antibacterial agent having deodorizing performance, which comprises gradually adding an aqueous solution of a water-soluble salt of a metal having an action and an aqueous solution of sodium silicon at the same time and separately, separating the resulting gel, and then drying it. 4. Gradually add an aqueous solution of a water-soluble salt of a metal having an antibacterial effect and an aqueous solution of sodium silicate to the mother liquor slurry simultaneously and separately, and separate a part of the resulting gel, and then use the slurry again as the mother liquor slurry. The method according to claim 3, characterized in that it is used repeatedly. 5.Claim 3, wherein the drying step is carried out at a temperature of 300°C or lower.
or the method described in 4.