JPH061707A - Production of antimicrobial agent - Google Patents

Abstract

PURPOSE:To provide a method for producing an antimicrobial agent suitable for using in the form of a mixture with a synthetic resin and excellent in safety. CONSTITUTION:B-form silica gel [Average particle diameter is about 2000mum] is added to a reaction solution between silver acetate, sodium sulfite and sodium thiosulfate so as to support a silver complex on silica gel. The resultant mixture of the thiosulfato silver complex solution and silica gel is heated at 60 deg.C and a reduced pressure of <= about 3000Pa so as to evaporate the solvent components for further drying it. The resultant silver complex-supporting silica gel, methyl alcohol, tetraethoxysilane and ion-exchange water are put in a vacuum dryer and, after completion of hydrolysis of tetraethoxysilane at 60 deg.C, excessive water and alcoholic components are evaporated at 50 deg.C and a reduced pressure of <= about 3000Pa so as to apply a silica coating thereto. The obtained material is dried and crushed, thus producing the antimicrobial agent having about 60mum average particle diameter.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an antibacterial agent in which an antibacterial metal is supported on silica gel.

[0002]

2. Description of the Related Art At present, synthetic resin products are often used around kitchens, bathrooms and the like. However, bacteria are generated on the surface of these synthetic resin products, which is unsanitary,
There was also the problem of being unsightly. On the other hand, conventionally, a method has been used in which an antibacterial agent is mixed with a synthetic resin to prevent propagation of various bacteria. As the antibacterial agent to be mixed with the synthetic resin, an organic nitrogen-based antibacterial agent has been mainly used because it has a sufficiently strong antibacterial action even when mixed in the synthetic resin.

[0003]

However, the organic nitrogen-based antibacterial agent has a problem that the antibacterial action is too strong and has an adverse effect on the human body and the natural environment. On the other hand, when a safe antibacterial agent having a weak antibacterial effect is used, there is a problem that the antibacterial effect cannot be obtained unless the antibacterial agent concentration is adjusted to be sufficiently high near the surface of the synthetic resin product.

As described above, a safe antibacterial agent suitable for use by being mixed with a synthetic resin has not yet been developed. It is an object of the present application to solve the above problems and provide a method for producing an antibacterial agent, which is suitable for use by being mixed with a synthetic resin and has excellent safety.

[0005]

According to the method for producing an antibacterial agent of the present invention, a solution containing a silver complex salt has an average particle size of 30 to 40.
After immersing 00 μm silica gel to support the silver complex salt on the silica gel, removing the solvent component and vacuum drying,
The silica gel surface is coated to give an average particle size of 1-
The gist is to grind to 10 μm.

As the solution containing a silver complex salt, for example, a thiosulfato silver complex salt solution can be used. The thiosulfato silver complex salt solution is prepared, for example, as follows. That is, 30 ml of pure water or ion-exchanged water is heated to 40 ° C., 0.232 g of silver acetate is added thereto, the mixture is stirred at 40 to 50 ° C. for about 5 minutes and then filtered to remove undissolved silver acetate.
Alternatively, vigorous stirring may be performed until all the silver acetate is dissolved. 1.0 g of sodium sulfite is added as a stabilizer to the solution thus obtained with stirring. Add sodium sulfite and stir until the white cloudy solution becomes clear.
Then, 0.66 g of sodium thiosulfate is added and stirred to prepare a thiosulfato silver complex salt solution.

About 30 ml of the silver complex salt solution thus obtained
On the other hand, 5.0 g of silica gel having an average particle diameter of 30 to 4000 μm is added and stirred for 10 minutes to support the silver complex salt on the silica gel. As silica gel, for example, product name Fuji Silica Gel B40up (average particle diameter 2000 μ
m: Fuji Davisson Chemical Co., Ltd.) can be used. When the average particle diameter of silica gel is out of the range of 30 to 4000 μm, the following problems occur. That is, when the average particle size of silica gel is larger than 4000 μm, the amount of silver complex salt carried on the silica gel after pulverization becomes uneven, and a sufficient antibacterial effect cannot be obtained. Also during the drying process,
It takes 2 before the amount of residual solvent for silica gel becomes the same.
Spend more than double the time. When the average particle size of silica gel is smaller than 30 μm, the following problems occur when removing the solvent component of the silver complex salt solution. That is, when a method of filtering with a filter paper is used to remove the solvent component, the silica gel particles are small in the solution, so that agglomeration occurs and it takes time to filter. Further, for example, when the solvent component is removed by evaporation under reduced pressure by an evaporator, since the silica gel particles are small, they are sucked into the vacuum pump,
The problem occurs that the vacuum pump is damaged.

After supporting the silver complex salt on silica gel, the solvent component is removed. When the solvent component is removed by filtration with a filter paper, for example, the filter paper (No. 2) is folded and filtered. When the solvent component is removed by evaporation in an evaporator, an evaporator that can evaporate the solvent component while mixing the contents under reduced pressure is suitable, for example, a rotary evaporator [product name "rotary Evaporator RE47 "manufactured by Yamato Scientific Co., Ltd., etc. can be used. Also, another vacuum dryer may be used instead of the rotary evaporator. Removal of the solvent component is about 3000 Pa or less,
It is preferable to carry out at a temperature of about 50 to 70 ° C.

Thereafter, the obtained silica gel is further dried in vacuum. For vacuum drying, the same evaporator as above can be used, and at about 3000 Pa or less,
It is preferable to carry out at a temperature of about 50 to 70 ° C. The silica gel supporting the silver complex salt thus obtained is coated. An organosilicon compound is suitable as a coating material, and for example, coating is performed as follows. First, 1 ml of ethyl alcohol and 1 ml of tetramethoxysilane (or tetraethoxysilane) are placed in a plastic container and stirred rapidly. 1 g of silica gel carrying a silver complex salt was added to this, and after stirring, 0.2 ml of pure water was added, followed by boiling in water and stirring for 30 minutes at 60 ° C. After hydrolysis of tetramethoxysilane was completed, excess water was added. The alcohol content is evaporated with a vacuum dryer. Then, the silica-coated silica gel is pulverized to have an average particle size of 1 to 10 μm. For the pulverization, for example, a counter jet mill 200AFG (manufactured by Hosokawa Micron) can be used. Average particle size after crushing is 10
If it is larger than μm, it becomes difficult to disperse it uniformly when mixed with a synthetic resin. The average particle size is 1 μm
Even smaller crushing has no further effect on the dispersion in the synthetic resin. The desired antibacterial agent is obtained as described above.

Further, another method for producing an antibacterial agent of the present invention is such that a solution containing a silver complex salt has an average particle size of 30 to 40.
After immersing 00 μm silica gel to support the silver complex salt on the silica gel, removing the solvent component and vacuum drying,
The essence is to pulverize to an average particle size of 1 to 10 μm and then coat the surface of silica gel.

The same silver complex salt solution and silica gel as described above can be used. Further, the removal of the solvent component of the silver complex salt solution and the vacuum drying can be performed by the same method as described above.
The silica gel after vacuum drying is pulverized by the same method as described above to have an average particle size of 1 to 10 μm. Then, the silica gel surface is coated by the same method as described above.

The average particle size of the crushed silica gel is 1 to 1
The reason for setting the thickness to 0 μm is, in addition to the above, in addition to the above, when silica gel loaded with a silver complex salt is coated, the surface of the silica gel is uniformly formed, and the antibacterial performance is easily maintained. Is also unlikely to occur.

[0013]

According to the method for producing an antibacterial agent of the present invention, it is possible to obtain an antibacterial agent in which a silver complex salt is supported on silica gel and further coated. Therefore, if this antibacterial agent is mixed with a synthetic resin product and used, The agent gradually releases a sufficiently high concentration of silver complex salt near the surface of the synthetic resin product, and an excellent antibacterial effect can be obtained for a long period of time. Also, after applying a silver complex salt to silica gel with a large average particle size for coating and then pulverizing it into small pieces, it is possible to obtain an antibacterial agent with a smaller average particle size while facilitating removal of the solvent component by filtration or an evaporator. To be Therefore, the antibacterial agent can be favorably dispersed in the synthetic resin. In addition, when silica gel is pulverized before coating, the particles of the antibacterial agent can be coated individually, so that the silver complex salt is supported in addition to the effect of the sustained release of the antibacterial component. When a coating is applied to the silica gel, the surface of the silica gel is formed into a uniform film, the antibacterial performance is easily maintained, and the discoloration of the silica gel is unlikely to occur.

Also, since a low-toxicity silver complex salt is used as the antibacterial component, a safe antibacterial agent can be produced.

[0015]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the description of the following examples unless it exceeds the gist. [Example 1] 78.1 kg of ion-exchanged water was heated to 40 ° C., 0.61 kg of silver acetate was added thereto, and the mixture was stirred at 40 to 50 ° C. for about 5 minutes and then filtered with a filter paper (No. 2) to obtain undissolved water. Remove silver acetate. To the solution thus obtained, 2.63 Kg of sodium sulfite was added with stirring. Sodium sulfite was added and the mixture was stirred until the white turbid solution became transparent, and then 1.74 Kg of sodium thiosulfate was added and stirred to obtain B-type silica gel [Product name "Fuji Silica Gel B
40 up ”: average particle diameter of about 2000 μm, manufactured by Fuji Devison Chemical Co., Ltd.] was added and stirred for 10 minutes to support a silver complex salt on silica gel. Then, a mixture of this thiosulfato silver complex salt solution and silica gel was added,
It was placed in a Nauta type NXU vacuum dryer (manufactured by Hosokawa Micron Co.) and the solvent component was evaporated at a temperature of 60 ° C. and about 3000 Pa or less to further dry.

The silica gel carrying the silver complex salt thus obtained was coated as follows. First, methyl alcohol 45l and tetraethoxysilane 4
5 l, 45 kg of silica gel carrying a silver complex salt and 9 l of ion-exchanged water were put in the same Nauta NXU vacuum dryer as above, and after the hydrolysis of tetraethoxysilane was completed at a temperature of 60 ° C., excess water and alcohol were added. Minutes to temperature 50
Evaporated at 3,000 ° C. and below about 3000 Pa to apply silica coating and dry. Then, the obtained silica gel was pulverized with a counter jet mill 200AFG (manufactured by Hosokawa Micron Co., Ltd.) at a rotation speed of 11500 rpm to obtain an antibacterial agent having an average particle diameter of about 60 μm. [Example 2] In the pulverization step of Example 1, a single track jet mill STJ-200 (manufactured by Seishin Enterprise Co., Ltd.) was used for pulverization twice instead of the counter jet mill, and the average particle diameter was 3.2 µm. The antibacterial agent was obtained. [Example 3] 12 l of ion-exchanged water was heated to 40 ° C, 92.8 g of silver acetate was added thereto, and the mixture was stirred at 40 to 50 ° C for about 5 minutes and then filtered through a filter paper (No. 2) to obtain undissolved silver acetate. To remove. 400 g of sodium sulfite was added to the solution thus obtained with stirring. Add sodium sulfite and stir until the white cloudy solution becomes clear, then
264 g of sodium thiosulfate was added and stirred, and B-type silica gel [Product name "BW silica gel BW300S": average particle diameter of about 40 μm, manufactured by Fuji Devison Chemical Co., Ltd.]
Was added for 8 minutes, and the mixture was stirred for 10 minutes to support a silver complex salt on silica gel. Then, the mixture of this thiosulfato silver complex salt solution and silica gel was put in a rotary evaporator [product name "rotary evaporator RE47" manufactured by Yamato Scientific Co., Ltd.] at a temperature of 50 to 70 ° C. and about 3000.
The solvent component was evaporated at Pa or less and dried.

The silica gel carrying the silver complex salt thus obtained was coated as follows. First, 8l of methyl alcohol and 8l of tetraethoxysilane
Then, 8 kg of silica gel supporting silver complex salt and 1.6 l of ion-exchanged water were put in a rotary evaporator to remove a solvent component at a temperature of 50 to 70 ° C. and about 3000 Pa or less to apply a silica coating, followed by drying.
Then, the obtained silica gel was vibrated mill crusher MB-1
It was pulverized for 35 hours with a mold (manufactured by Chuo Kakoki Co., Ltd.) to obtain an antibacterial agent having an average particle diameter of about 2.70 μm. [Example 4] 17.15 l of ion-exchanged water was heated to 40 ° C, 133 g of silver acetate was added thereto, and the mixture was heated to about 5 ° C at 40 to 50 ° C.
After stirring for a minute, the mixture is filtered through a filter paper (No. 2) to remove undissolved silver acetate. 572 g of sodium sulfite was added to the solution thus obtained with stirring. Add sodium sulfite and stir until the white cloudy solution becomes clear,
Then, add 377 g of sodium thiosulfate and stir,
B type silica gel [Product name "BW silica gel BW300
S ”: average particle size of about 40 μm, manufactured by Fuji Davisson Chemical Co., Ltd.] was added to 2.85 kg, and the mixture was stirred for 10 minutes to support a silver complex salt on silica gel. Then, the mixture of this thiosulfato silver complex salt solution and silica gel was put into a vibration fluidized dryer VH-25 [manufactured by Chuo Kakoki Co., Ltd.], and the solvent component was evaporated and dried at a temperature of 60 ° C. and about 3000 Pa or less. Let

The silica gel carrying the silver complex salt thus obtained was applied to a single track jet mill STJ-200.
It was pulverized three times using a [manufactured by Seishin Enterprise Co., Ltd.] to obtain a silica gel carrying a silver complex salt having an average particle diameter of 3.3 μm. The silica gel thus obtained was coated as follows. First, methyl alcohol 1
After putting 0 ml, 10 ml of tetraethoxysilane, 10 g of silica gel supporting a silver complex salt and 2 ml of ion-exchanged water into a rotary evaporator, the hydrolysis of tetraethoxysilane was completed at a temperature of 50 ° C., and then excess water and alcohol were added to the temperature. An antibacterial agent was obtained by evaporating at 50 ° C. and about 3000 Pa or less by a rotary evaporator. [Measurement of MIC (Minimum Inhibitory Concentration)] Examples 1 to 1 above
Using the antibacterial agent of No. 4 as a sample, the minimum inhibitory concentration was measured by the following method. That is, the agar plate medium to which each sample was added at an arbitrary concentration was inoculated and cultured with the inoculum bacterial solution, and the minimum concentration of the growth-inhibited antibacterial agent was defined as the minimum inhibitory concentration of the sample against various microorganisms. The results are shown in Table 1.

However, the preparation of the agar plate medium, the preparation of the inoculum bacterial solution, and the culture were carried out as follows. -Preparation of agar plate medium With sterile purified water, 200,000 ppm, 100,
000ppm, 50,000ppm, 25,000pp
m, 12,500ppm, 6,250ppm, 3,13
0ppm, 1,560ppm, 780ppm, 390p
pm, 200ppm, 100ppm, 50ppm, 25
ppm, 12.5 ppm suspension was prepared. Next, a medium for sensitivity measurement (Muell, which became 50 to 60 ° C. after dissolution)
Each suspension was added to er-Hinton agar medium (DIFCO) in an amount of 1/9 of the medium, mixed well, and then divided into a petri dish and solidified to obtain an agar plate medium.・ Preparation of bacterial solution for inoculation Enrichment medium [Mueller Hinton Broth (Muel
Ler-Hinton Broth (manufactured by DIFCO)], the bacterial solution of the test strain that had been cultured overnight at 35 ° C. was diluted with the same medium so that the number of bacteria per ml was about 10 ⁶ . However, the following strains were used as test strains.

Escherichia coli: Escherichia coli (Esc
herichia coli) IFO 3301 Staphylococcus aureus: Staphylococcus aureus (S
taphylococcus aureus) 127
32. Culturing The bacterial solution for inoculation was smeared on an agar plate medium with a nichrome wire loop (internal diameter of about 1 mm) for about 2 cm, and cultured at 35 ° C. for 1 day.

[0021]

[Table 1]

As is clear from Table 1, the agar plate medium containing the antibacterial agents of Examples 1 to 4 was able to inhibit the growth of bacteria at a low concentration. [Antifungal Antibacterial Test of Synthetic Resin Mixture] The antibacterial agents produced in Examples 1 to 4 were uniformly mixed and dispersed at a ratio of 5 parts by weight of the antibacterial agent to 100 parts by weight of the resin at the time of molding the unsaturated polyester resin. Molded. On the other hand, as a comparative example, a resin containing no antibacterial agent was molded.

The anti-mold and anti-bacterial test shown below was carried out on the synthetic resin moldings containing the anti-bacterial agents of Examples 1 to 4 and the comparative synthetic resin moldings. The results are shown in Table 2.・ Antifungal test Mold resistance test of Japanese Industrial Standard (JIS Z 291
The test was carried out according to the halo test method by the mildew proof test for textiles of 1). The mold used was Cladosporium clado.
sporioides), ketomium globosum (C
haetomium globosum, Penicillium citrinum (Penicillium citri)
num), Aspergillus niger
lus niger). Evaluation was carried out 14 days later. -Antibacterial test The antibacterial test was carried out according to the above hello test method. The fungus is Escherichia col
i), Staphylococcus aureus (Staphy)
lococcus aureus) and Bacillus subtilis (Bacillus subtilis) were used. Evaluation was carried out after 7 days.

[0024]

[Table 2]

As is clear from Table 2, the synthetic resin moldings containing the antibacterial agents of Examples 1 to 4 suppress the generation of mold and fungi on the surface of the synthetic resin, as compared with the comparative example containing no antibacterial agent. The power to do is excellent. As described above, the antibacterial agents produced in Examples 1 to 4 have excellent antibacterial effect. Moreover, when mixed with a synthetic resin and molded, it has an excellent effect of suppressing the growth of mold and fungi on the surface of the synthetic resin molded product. Furthermore, after applying a silver complex salt to silica gel having a large average particle diameter for coating and then pulverizing it into small particles, an antibacterial agent having a smaller average particle diameter can be obtained while easily performing filtration or removal of the solvent component by an evaporator. The antibacterial agent was well dispersed in the synthetic resin. Further, since a silver complex salt is used as an antibacterial component, it is highly safe.

Further, according to Example 4, since the silica gel was crushed before the coating, the particles of the antibacterial agent can be coated individually, and the same effect as the above-mentioned sustained release of the antibacterial component can be obtained. In addition, when silica gel carrying a silver complex salt is coated, the surface of the silica gel is uniformly formed, and the antibacterial performance is easily maintained, and discoloration of the silica gel is unlikely to occur.

Further, the antibacterial agents produced in Examples 1 to 4 may be mixed with a synthetic resin molded product or may be mixed with a paint and applied to the surface of stainless steel or the like. Although contained in the average particle diameter of 30 to 4000 μm, antibacterial agents produced by using silica gel having an average particle diameter other than the above examples as a carrier also showed similar effects. Further, the average particle size after pulverization is also included in the average particle size of 1 to 10 μm, but antibacterial agents pulverized to an average particle size other than the above examples also showed the same effect.

[0028]

As described above, according to the present invention,
It is possible to provide a method for producing an antibacterial agent which is suitable for being mixed with a synthetic resin and which is excellent in safety.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Nishino 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kozo Yamamoto 2-1846 Kozoji-cho, Kasugai-shi, Aichi Fuji-Davison Chemical Co., Ltd.

Claims (2)

[Claims] 1. A solution containing a silver complex salt has an average particle size of 3
It is characterized in that the silica gel of 0 to 4000 μm is dipped to support the silver complex salt on the silica gel, the solvent component is removed and vacuum dried, and then the surface of the silica gel is coated and ground to an average particle diameter of 1 to 10 μm. A method for producing an antibacterial agent. 2. A solution containing a silver complex salt has an average particle size of 3
After immersing 0 to 4000 μm silica gel, supporting the silver complex salt on the silica gel, removing the solvent component and vacuum drying, crushing to an average particle size of 1 to 10 μm, and then coating the silica gel surface. A method for producing a characteristic antibacterial agent.