JPH0751486B2 - Antibacterial agent having deodorizing performance and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel antibacterial agent having an antibacterial activity against various bacteria and an adsorption activity against various malodors, and a method for producing the same.

<Prior Art> Conventionally, in an antibacterial agent, a metal such as silver having an antibacterial effect or a compound thereof is adsorbed to an adsorbent such as zeolite, activated carbon, activated alumina, or silica gel and used for antibacterial and / or adsorption purposes. It is known. Other,
Many organic substances have been devised.

<Problems to be Solved by the Invention> However, by simply adsorbing a metal or a compound thereof having an antibacterial action to such a conventional adsorbent, stability, antibacterial effect, persistence of adsorption effect, etc. It is hard to say that it is enough. In addition, organic systems have drawbacks such as poor heat resistance and high vapor pressure.

The present invention has been made by paying attention to such conventional problems, and stabilizes a metal having an antibacterial effect in an active state to have a long-lasting antibacterial effect and a good adsorption performance. The purpose of the present invention is to provide an antibacterial agent.

<Means and Actions for Solving Problems> In order to achieve the above object, the present inventor has earnestly studied, and as a result, a metal having an antibacterial action was used as an oxide to form an amorphous composite with an antibacterial substance. It has many advantages in terms of long-lasting effect, stability of antibacterial substances, heat resistance, etc., and it also chemically adsorbs malodorous gases such as ammonia, amines, hydrogen sulfide, and mercaptans by coordination bond with metals. The present invention has been accomplished by discovering that this is done.

The above-mentioned amorphous composite of an oxide of a metal having an antibacterial effect and silicon dioxide is obtained by mixing and reacting an aqueous solution of a water-soluble salt of a metal having an antibacterial effect with an aqueous solution of sodium silicate to give a gel. It can be produced by drying. However, the above manufacturing method has the following drawbacks. When the reaction is carried out under the condition of low water content, the gel produced becomes extremely high in viscosity,
A uniform reaction is unlikely to occur. This tendency increases as the concentration of the raw material aqueous solution increases, and the gel becomes a lumpy solid matter depending on the conditions. In this case, gelation begins earlier than when the raw material aqueous solution is uniformly mixed, and the viscosity rises rapidly, making homogenization difficult. As a result, the performance of the antimicrobial agent produced is poorly reproducible. In addition, a homogeneous gel with a relatively low viscosity can be obtained under conditions of low water content, but this gel has poor filterability, and since the water content after solid-liquid separation exceeds 80%, it takes an extremely long time for filtration and drying. Requires.

As a result of further research to solve these drawbacks, the following manufacturing method was invented. That is, the production of the antibacterial agent having the deodorizing performance according to the present invention is carried out by mixing an aqueous solution of a water-soluble metal salt having an antibacterial effect and an aqueous solution of sodium silicate so that the water content in the reaction system becomes 85% or more. , To prepare an amorphous complex slurry of gelled metal oxide and silicon dioxide by reacting, and using this slurry as a mother liquor, a new aqueous solution of a water-soluble salt of the above metal and silica while keeping the pH at 6.5 to 8.0. After gradually adding the aqueous solution of sodium acid separately and separately, and separating the resulting gel,
It is characterized by being dried.

According to the method of the present invention, since the raw material liquid is added to the mother liquor to be diluted, the reaction is carried out in a state of being mixed almost uniformly. Further, since the raw material components are always present in a diluted state in the mother liquor, and the pH of the mother liquor slurry is kept substantially constant throughout the reaction, a homogeneous gel-like amorphous metal oxide and silicon dioxide composite A product slurry can be obtained. Further, the gel obtained at this time has a relatively low water content of 50 to 80%, and thus has good filterability and dryability.

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

In carrying out this manufacturing method, first, an aqueous solution of a water-soluble salt of a metal having an antibacterial action 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 reacted. An amorphous complex slurry of a metal oxide and silicon dioxide is produced to obtain a mother liquor slurry. At this time, if the water content is less than 85%, the viscosity of the slurry is high and it is difficult to stir, which is not suitable as a mother liquor slurry. Next, while stirring this mother liquor slurry, an aqueous solution of each raw material is newly added to this slurry simultaneously and separately. Thus, the water content is 50-80 with good filterability.
% Amorphous metal oxide and silicon dioxide complex is formed in the mother liquor.

Further, the slurry obtained by removing a part of the slurry obtained by the simultaneous addition reaction method as described above can be repeatedly used again as the mother liquor slurry. Since the viscosity of the slurry at this time is remarkably lowered by the effect of the simultaneous addition reaction, the water content does not need to be 85% or more. In the reaction that is repeatedly performed thereafter, by setting the slurry pH during the reaction to 6.5 to 8.0, a gel with a water content of 50 to 80% with good filterability can be obtained even when the water content in the system is less than 85%. It is possible.

The gel prepared as above is filtered, washed with water to remove the by-produced sodium salt, and then dried at a temperature of 300 ° C. or lower to obtain an amorphous metal oxide and silicon dioxide having an antibacterial action. An antibacterial agent having a deodorizing performance, which is composed of a complex of When the drying temperature exceeds 300 ° C, the specific surface area of the antibacterial agent is extremely reduced, and the antibacterial activity and the adsorptive power tend to be reduced.

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, when the pH of the slurry during the reaction is kept at 6.5 or less, the slurry has a relatively high viscosity, and the resulting gel has a high water content and poor filterability. When the pH is set to 6.5 to 8.0, preferably 7.0 to 7.5, the viscosity of the slurry becomes extremely low and a gel having a good sedimentation property is formed. The gel obtained under these conditions has a water content of 50 to 80% and has extremely good filterability. Slurry pH
When it exceeds 8.0, the water content of the obtained gel is low, but the deviation from the pH at the reaction equivalent becomes large, which is not preferable.

The actual adjustment of the pH of such a slurry is made possible by slightly changing the rate of addition of metal salt and sodium silicate. That is, if the metal salt is supplied to the reaction vessel while keeping it somewhat in excess of sodium silicate, the pH of the slurry during the reaction becomes slightly acidic, and vice versa. In the actual reaction, Na ₂ O in water glass was used.
When an equivalent amount of the metal salt is reacted with, the pH of the resulting slurry becomes 6.5 to 7.5.

In addition, during the reaction, antibacterial agents having various ratios of metal oxide and silicon dioxide can be prepared by neutralizing the excess sodium content with an acid with a metal salt being a deficient equivalent.

<Examples> Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the Examples are described merely for the purpose of illustration, and the present invention is not limited to these Examples. For products in combination with other combinations selected from silver, copper, zinc and combinations with other metals, the effect,
Needless to say, the manufacturing method and the like can be easily estimated and are included in the present invention.

The antibacterial test in the examples was carried out by the following method: A powder sample was placed in a 300-ml triangular Kolben, and 100 ml of each bacterial solution (Escherichia coli, Staphylococcus aureus) was added, and the mixture was shaken at room temperature. After 24 hours, the number of bacteria was measured.

The deodorization test was conducted as follows: 0.5 g of the powder sample was placed in a Tedlar bag filled with gas 3 having a predetermined concentration diluted with nitrogen gas. The change with time of the gas concentration was measured with a gas detector tube.

Comparative Example 1 19.8 g of zinc sulfate ZnSO ₄ .7H ₂ O was dissolved in 50 ml of water. on the other hand,
50 g of water glass No. 3 was diluted with 170 ml of water. These raw material solutions were mixed to form a gel, which was allowed to stand at room temperature for 90 minutes for aging. The pH of the gel slurry was 6.8. 200 ml of gel slurry is suction filtered with a Buchner funnel with a diameter of 10 cm,
It was washed 5 times with 100 ml of water. A filtration time of 15-20 minutes per 100 ml of wash water was required. Antibacterial agent A was obtained after drying in a 200 ° C. dryer for 10 hours. Loss on drying is 88%, specific surface area is 185m ² / g
Met.

Example 1 200 ml of the gel slurry prepared in the same manner as in Comparative Example 1 was placed as a mother liquor in a 3-volume beaker, and the 0.67 mol / dm ³ ZnSO ₄ aqueous solution and 0.7 mol / dm ³ Na were added while stirring the mother liquor at 250 rpm.
Each 1 of ₂ O-2.1 mol / dm ³ SiO ₂ aqueous solution was added separately at 5.5 ml / min. The pH of the slurry during the reaction was 7.2-7.5. 200 ml of this slurry was filtered in the same manner as in Comparative Example 1, and the obtained gel was washed with water. The filtration time per 100 ml of washing water was 30 to 40 seconds. Wash gel after washing at 110 ℃, 200
Antibacterial agent B- dried at ℃ and 300 ℃ respectively
1, B-2 and B-3. Loss on drying is about 75%,
The specific surface areas were 365, 198 and 163 m ² / g, respectively.

Comparative Example 2 The gel obtained in Example 1 was washed with water and dried at 500 ° C. to obtain antibacterial agent C. The specific surface area was 70 m ² / g.

Example 2 45.3 g of copper sulfate CuSO ₄ .5H ₂ O was dissolved in 250 ml of water. on the other hand,
125 g of water glass No. 3 was diluted with 500 ml of water. These raw material liquids were mixed to form a gel. Using 400 ml of this slurry as the mother liquor, 0.6 mol / dm ³ CuSO ₄ aqueous solution and 0.6 mol / dm ³ Na ₂
Each 2 of O-1.8 mol / dm ³ SiO ₂ aqueous solution was added separately at 6.0 ml / min and reacted at the same time. The mother liquor is stirred at 350 rpm,
The pH during the reaction was 6.8 to 7.2. The produced gel was filtered, washed with water, and dried at 110 ° C. for 6 hours to obtain antibacterial agent D.
The specific surface area was 340 m ² / g.

Example 3 1.23 g of silver sulfate AgNO ₃ and 11.9 g of 69% nitric acid were dissolved in water to make 100 ml. On the other hand, 50 g of water glass No. 3 was diluted with 100 ml of water. These raw material liquids were mixed to form a gel. This was left to stand at room temperature for 60 minutes for aging. Filter the gel and wash with water 11
Antibacterial agent E was obtained after drying at 0 ° C. for 10 hours. Specific surface area is 315 m ²
It was / g.

EXAMPLE 4 Silver nitrate AgNO ₃ 1.23 g of copper nitrate _{Cu (NO 3) 2 · 3H} 2 O7.01g and zinc nitrate _{Zn (NO 3) 2 · 6H} 2 O11.88g was dissolved in water 150 ml. On the other hand, 50 g of water glass No. 3 was diluted with 150 ml of water. Thereafter, an antibacterial agent F was obtained in the same manner as in Example 3. The specific surface area was 325 m ² / g.

When the antibacterial agents A to 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 in. It can be seen that it can be sufficiently used for deodorizing and antibacterial purposes. Antibacterial agents B-1, B-2 and B-obtained in Example 1
Comparing No. 3 with the antibacterial agent C obtained in Comparative Example 2, it can be seen that the performance is extremely lowered by drying at 500 ° C.

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

<Effects of the Invention> As described above, the amorphous composite of the metal oxide having an antibacterial action and silicon dioxide according to the present invention has the following effects and characteristics.

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

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

3. Quickly adsorb and deodorize malodorous components such as ammonia, hydrogen sulfide, mercaptans, and amines.

4. Raw materials are inexpensive.

5. Easy to manufacture.

Further, the amorphous composite of the metal oxide having an antibacterial action and silicon dioxide according to the present invention is not only used as a powder or granules because of the above characteristics,
It is also possible to add antibacterial and deodorizing properties to the base material by adding and processing it to the base material such as various plastics, papers, fibers, etc., and its application range is extremely wide.

The production method according to the present invention makes it possible to prepare an amorphous composite gel of a homogeneous metal oxide and silicon dioxide. Further, since the gel has a good filterability and a relatively low water content, there is an advantage that the filtration and drying steps can be greatly shortened in the industrial production thereof and the economy is good. Also,
It can be applied not only to metals having antibacterial action but also to other metals.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area A61K 33:24 33:30 33:34)

Claims (5)

[Claims] 1. An antibacterial agent having a deodorizing property, which comprises an amorphous composite of a metal oxide having an antibacterial effect and silicon dioxide. 2. The antibacterial agent having a deodorizing property according to claim 1, wherein the metal having an antibacterial effect is selected from silver, copper and zinc. 3. An aqueous solution of a water-soluble salt of a metal having an antibacterial action and an aqueous solution of sodium silicate are mixed so that the water content in the reaction system is 85% and reacted to form a gel metal oxide. Amorphous composite slurry with silicon dioxide is prepared, and the aqueous solution of a water-soluble salt of a metal having a new antibacterial action and the aqueous solution of sodium sodium are newly separated at the same time while using the slurry as a mother liquor to maintain the pH at 6.5 to 8.0. A method for producing an antibacterial agent having a deodorizing property, which is characterized in that the gel produced is gradually added and then separated, and then dried. 4. An aqueous solution of a water-soluble metal salt having an antibacterial action and an aqueous solution of sodium silicate are gradually added to the mother liquor slurry at the same time separately, and a part of the resulting gel is separated, and then the slurry is again prepared. The method according to claim 3, which is repeatedly used as a mother liquor slurry. 5. The method according to claim 3, wherein the drying step is performed at a temperature of 300 ° C. or lower.