JPH08113729A - Antibacterial composition and method for producing the same - Google Patents

Abstract

(57) [Summary] [Object] To provide an antibacterial composition and a method for producing the same. An antibacterial composition mainly comprising silica fine particles adsorbing and supporting zinc sulfate, wherein the silica fine particles have an average particle size of 1 μm or less, and the proportion of zinc sulfate adsorbing and supporting on the silica fine particles. Is 10 to 40 parts by weight with respect to 100 parts by weight of silica fine particles, and is an antibacterial composition for kneading plastics or adding a paint for painting plastics, and zinc sulfate By adsorbing and supporting the heptahydrate on silica fine particles in the state of an aqueous solution and heating and drying in the temperature range of 40 to 280 ° C., the crystal water structure is changed from heptahydrate to hexahydrate, monohydrate, and anhydrous salt. It is a method for producing an antibacterial composition, which comprises degrading water stepwise. [Effect] The antibacterial effect can be maintained for a long period of time, and discoloration due to ultraviolet rays or chemical reaction does not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial composition mainly composed of silica fine particles having zinc sulfate adsorbed thereon and a method for producing the same.

[0002]

2. Description of the Related Art Chlorite salts such as sodium chlorite are well known as antibacterial and antifungal agents. Further, a powder obtained by adsorbing this chlorite salt as an aqueous chlorite solution onto a porous powder such as activated carbon, zeolite or calcium silicate or a water-absorbing powder is also known as an antibacterial and antifungal agent. Also,
As a relatively safe antibacterial composition for plastics, a silver-based antibacterial composition such as a silver ion-supporting zeolite is often used.

[0003]

However, the above-mentioned chlorite itself is extremely unstable and decomposes to generate chlorine dioxide, chlorine gas and oxygen gas, and has a drawback that it is easily volatilized. In addition, a substance obtained by adsorbing an aqueous chlorite solution on a porous powder or a water-absorbing powder is decomposed when heated to 80 ° C. or higher, and gas is volatilized, so that the chlorite disappears in a short time. It has drawbacks. further,
Since these known adsorption compositions contain water even when they are in powder form, they are a cause of various troubles when they are used for plastics, organic solvent-based paints and the like. When solid chlorite is pulverized as it is into powder, there is a risk of explosion due to impact.

On the other hand, silver-based antibacterial compositions such as zeolite carrying silver ions are remarkably discolored by ultraviolet rays and are difficult to use especially for outdoor applications. It also involves the problem of discoloration due to the chemical reaction of silver. The present invention solves the above-mentioned problems in the prior art, prevents volatilization and disappearance of antibacterial components due to decomposition, etc., maintains a stable state even when heated, removes harmful effects due to water, and has a risk of explosion due to crushing. It is an object of the present invention to provide an antibacterial composition that does not generate ultraviolet rays or discoloration due to a chemical reaction, and a method for producing the same.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the inventors of the present invention have conducted extensive studies, and as a result, silica fine particles adsorbing and supporting zinc sulfate have excellent antibacterial properties for a long period of time. The inventors have found that they are also excellent in stability and have completed the present invention. That is, the present invention made based on the above-mentioned findings is based on an antibacterial composition mainly composed of silica fine particles that adsorb and support zinc sulfate, and the average particle diameter of the silica fine particles is 1 μm or less, The ratio of zinc sulfate adsorbed and supported on the silica fine particles is
The gist of the antibacterial composition is 10 to 40 parts by weight with respect to 100 parts by weight of silica fine particles.

Further, it is also possible to use the antibacterial composition containing silica fine particles having zinc sulfate adsorbed thereon as a main component for kneading plastics and for adding a paint to be applied to plastics. Further, zinc sulphate heptahydrate is adsorbed and supported on silica fine particles in the state of an aqueous solution, and heated and dried within a temperature range of 40 to 280 ° C. to change the crystal water structure from heptahydrate to hexahydrate. The gist of the present invention is also a method for producing an antibacterial composition, which comprises stepwise decrystallizing water into a water salt or an anhydrous salt.

[0007]

The structure and operation of the present invention will be described. The zinc sulfate used in the present invention has hitherto been widely used as a pigment, a mordant, an antiseptic and a medicine. In the present invention, generally, commercially available zinc sulfate heptahydrate can be used, but the number of crystal water may be any number of compounds or anhydrous salts.

The silica fine particles used in the present invention include fine particles of quartz, silica stone, diatomaceous earth, etc. as natural products, and as synthetic products, ultrafine silica particles commonly called white carbon and dehumidifying, drying, gas. Silica gel for adsorption, etc.
There are compounds whose main component is silicon dioxide. When the average particle size of the silica fine particles exceeds 1 μm, when these silica fine particles that adsorb and support zinc sulfate are kneaded into plastics or added to paints, poor dispersion occurs and becomes unstable. Therefore, it is not preferable.

When zinc sulfate is directly kneaded into plastics or dispersed in a paint without being adsorbed and supported on silica fine particles as in the present invention, agglomeration or the like occurs even if the particle size of zinc sulfate is 1 μm or less. Therefore, it is difficult to disperse zinc sulfate in the form of fine particles of 1 μm or less. The amount of zinc sulfate adsorbed and supported on the silica fine particles is 10 to 40 with respect to 100 parts by weight of the silica fine particles.
Parts by weight are preferred. If the amount of zinc sulfate exceeds 40 parts by weight, the dispersibility will be poor. Further, if the amount is less than 10 parts by weight, the antibacterial property is deteriorated. Therefore, a large amount of the carried silica fine particles must be kneaded into the plastics or dispersed in the paint, resulting in poor workability and impractical.

The plastics, rubbers, paints, etc., in which the silica fine particles adsorbing and supporting zinc sulfate according to the present invention are kneaded, and the film, molded product or coating film in which these are dispersed have a long-lasting antibacterial function. In addition, there is no problem of discoloration due to ultraviolet rays such as silver ions or discoloration due to a specific chemical reaction.

As the plastics capable of kneading the silica fine particles adsorbing and supporting zinc sulfate of the present invention, polyolefin resin, vinyl chloride resin, styrene resin, urethane resin, acrylic resin, silicone resin, polyamide resin, polyvinylidene resin can be used. Resin, polyester resin,
It can be used for all commonly known plastics such as epoxy resin. Kneading amount is plastics 9
With respect to 9 to 95% by weight, 1 to 5% by weight of silica fine particles having zinc sulfate adsorbed thereon is preferable. As a kneading method, a masterbatch can be used for kneading, and in the case of a sheet, it can be dispersed by rolls.

The type of plastics as an object to be coated in the case where the silica fine particles having zinc sulfate adsorbed and supported thereon according to the present invention is used by coating with plastics and used is particularly limited as long as it is a plastics which can be coated. There is no. Examples of these plastics include polyolefin resin, vinyl chloride resin, styrene resin, urethane resin, acrylic resin, silicon resin, polyamide resin, polyvinylidene resin, polyester resin, and epoxy resin.

The types of paints that can be used in the above cases include fatty acid type paints, epoxy resin type paints, vinyl ester resin type paints, polyurethane resin type paints, silicone resin type paints, fluororesin type paints, vinyl resin type paints, There are vinyl chloride resin-based paints, acrylic resin-based paints, and the like, and the addition amount of silica fine particles that adsorb and support zinc sulfate is preferably 1 to 5 parts by weight with respect to 100 parts by weight of the heating residue of the paint. As a coating method, spray coating, dip coating, roll coating, or the like can be applied according to the coating method of the paint before addition.

The zinc sulfate heptahydrate of the present invention is adsorbed and supported on silica fine particles in the state of an aqueous solution, and is heated and dried within a temperature range of 40 to 280 ° C. to form a crystal water structure from heptahydrate to hexahydrate. In a method for producing an antibacterial composition mainly composed of silica fine particles adsorbing and supporting zinc sulfate, which comprises decrystallizing water into monohydrate and anhydrous salt in stages, heating and drying are performed at 40 to 40% as the first step. 70 ° C., 70 to 100 ° C. as the second stage, and 240 to 280 ° C. as the third stage.
A method performed in stages is preferred. This is because zinc sulfate heptahydrate turns into hexahydrate by heating at 40 to 70 ° C, and further 70 to 1
This is because it is presumed that the hexahydrate is changed stepwise from 00 ° C to the monohydrate and from 240 to 280 ° C from the monohydrate to the anhydrous salt.

When the heating and drying temperature is raised to a high temperature of 70 ° C. or higher in one step, zinc sulfate is dissolved in the water of crystallization to cause the disadvantage that particles are fused. In addition, at a higher temperature of 100 ℃
There is a disadvantage that scattering phenomenon occurs when the temperature is raised above the above.
When the silica fine particles carrying an aqueous solution of zinc sulfate heptahydrate are dried by heating, the crystal water of zinc sulfate heptahydrate cannot be dehydrated below 40 ° C. Further, there is no particular problem when the temperature exceeds 280 ° C. to 700 ° C., but there is a drawback that heating energy is lost. If the temperature exceeds 700 ° C, the zinc sulfate itself is decomposed and the antibacterial property disappears.

[0016]

EXAMPLES The present invention will be described in more detail with reference to examples, comparative examples and application examples of the present invention, but the present invention is not limited thereby. Examples, comparative examples,
Parts and% in application examples are parts by weight and% by weight, unless otherwise specified. Example 1 130 g of a 55% aqueous solution of zinc sulfate heptahydrate was added to 100 g of silica fine particles (Zeosil 1100V, manufactured by Taki Kagaku Co., Ltd., particle size 0.02 to 0.03 μm), and dispersed for 20 minutes with a dry batch attritor. After that, 60 ℃ × 1 hour,
Then, the mixture was heated and dried at 100 ° C. for 1 hour and then at 260 ° C. for 1 hour to produce an antibacterial composition of the present invention in which 40.0 parts of zinc sulfate anhydrous salt was adsorbed and supported on 100 parts of silica fine particles.

Example 2 In Example 1, 1% of a 55% aqueous solution of zinc sulfate heptahydrate was added.
The antibacterial composition of the present invention was produced under the same conditions as in Example 1, except that the amount of anhydrous zinc sulfate was changed to 10 g and the amount shown in Table 1 was changed.

[0018]

[Table 1]

Example 3 ABS resin pellets (Toyolac ABS # 700, manufactured by Toray Industries, Inc.) were melted with a mixing roll adjusted to 250 ° C., and then 33.9 parts of zinc sulfate anhydrous salt was added to 100 parts of silica fine particles. The adsorbed and supported product was added at a ratio of 1 part to 100 parts of ABS resin pellets, kneaded for 10 minutes, and then 1100 k with a press molding machine adjusted to 230 ° C.
A pressure of g / cm ² was applied for 7 minutes to form an ABS resin sheet having a thickness of 2 mm and containing silica particles adsorbing zinc sulfate, which is the antibacterial composition of the present invention.

Examples 4 and 5 The present invention was carried out under the same conditions as in Example 3, except that the amount of zinc sulfate-adsorbing silica fine particles contained in the ABS resin sheet was changed to the amount shown in Table 1 in Example 3. An ABS resin sheet in which the antibacterial composition was kneaded was molded.

Examples 6 and 7 To 100 parts of vinyl chloride paste sol (TOP base, manufactured by Asahi Chemical Industry Co., Ltd.), 100 parts of silica fine particles were adsorbed and supported with 40.0 parts of zinc sulfate anhydrous salt, respectively. 1 part and 3 parts were added, and the respective solutions, which were sufficiently stirred and homogenized, were coated on a release paper with a bar coater, and 2
Two kinds of vinyl chloride sheets containing the antibacterial composition of the present invention having a thickness of about 0.2 mm were prepared by heating and drying at 00 ° C for 120 seconds.

Examples 8 to 10 A lacquer type acrylic resin paint for plastics (manufactured by Honey Kasei Co., Ltd.) was adsorbed and supported on 100 parts of silica fine particles and 30 parts of anhydrous zinc sulfate was adsorbed on 100 parts of the heating residue. Was added at a ratio of 1.3 parts and 5 parts, respectively, and the respective solutions, which were sufficiently stirred and homogenized, were air-spray coated on one surface of an acrylic resin plate having a thickness of 2 mm so that the dry film thickness was about 10 μm. Then, two kinds of coating films containing the antibacterial composition of the present invention were obtained.

Example 11 55% of zinc sulfate heptahydrate based on 100 g of silica fine particles
After adding 33 g of the aqueous solution and dispersing for 20 minutes with a dry batch attritor, 60 ° C x 1 hour, then 100 ° C x 1
The mixture was heated and dried for 1 hour at 260 ° C. for 1 hour to obtain an antibacterial composition of the present invention in which 10.2 parts of anhydrous zinc sulfate was adsorbed and supported on 100 parts of silica fine particles. 5% of this antibacterial composition was added to 100 parts of the heating residue of a lacquer type acrylic resin paint for plastics (manufactured by Honey Kasei Co., Ltd.).
The solution added at a ratio of 1 part and thoroughly stirred and homogenized has a thickness of 2
mm ABS resin plate was air-spray coated on one side to a dry film thickness of about 10 μm to obtain a coating film containing the antibacterial composition of the present invention.

Comparative Example 1 In Example 1, 1% of a 55% aqueous solution of zinc sulfate heptahydrate was used.
A comparative antibacterial composition was obtained under the same conditions as in Example 1 except that the amount of anhydrous zinc sulfate was changed to 40 g and the amount of zinc sulfate anhydrous was changed to the amount shown in Table 1. Comparative Example 2 An antibacterial composition for comparison under the same conditions as in Example 1 except that the amount of zinc sulfate adsorbed and supported on 100 parts of silica fine particles was changed to the amount shown in Table 1 in Example 11. Got

Comparative Example 3 The blank test ABS resin sheet was prepared under the same conditions as in Example 3 except that the amount of the antibacterial composition contained in the ABS resin sheet was changed to the amount shown in Table 1. Got Comparative Example 4 In Examples 6 and 7, except that the amount of the antibacterial composition to be contained in the vinyl chloride paste sol was changed to the amount shown in Table 1, all were subjected to the blank test chloride under the same conditions as in Examples 6 and 7. A vinyl resin sheet was obtained. Comparative Example 5 In Examples 8 to 10, the amount of the antibacterial composition to be added to the lacquer type acrylic resin coating material for plastics is shown in Table 1.
An acrylic resin sheet for blank test was obtained under the same conditions as in Examples 8 to 10, except that the amount was changed to the amount shown in.

Application Example 1 An application example of the antibacterial composition of the present invention and a method for producing the same, and performance evaluation results thereof will be described. (1) Adsorption state When the adsorption state of zinc sulfate in the antibacterial compositions obtained in Examples 1 and 2 and Comparative Example 1 was observed with an X-ray microanalyzer (manufactured by Shimadzu Corporation), Examples 1 and 2 were uniform. On the other hand, in the case of Comparative Example 1, a non-uniform state was observed.

(2) Antibacterial test Escherichia coli IFO
330) and Staphylococcus aureus
Us aureus IFO 13276) as a test bacterium, and each test bacterium is inoculated into nutrient broth (commercial medium) and cultured at 37 ° C. for 24 hours. This broth is diluted 100 times with a phosphate buffer solution (commercially available product) to obtain a test bacterial solution. Next, 2 sheets (50 mm × 50 mm) of each of the samples obtained in Examples 3 to 5 and Comparative Example 3 were placed in a sterilized petri dish, and 100 μl of the test bacterial solution was dropped in the center thereof, and one sheet was immediately rinsed with 10 ml. (Lecithin: 40
g, Tween-80: 280 g, 0.25 M phosphate buffer stock solution: 1.25 ml was mixed with distilled water to give a total volume of 1000
A neutralization stock solution (50 ml), a 0.25M phosphate buffer stock solution (12.5 ml), and distilled water (937.5 ml) are mixed. 10 ml of this was put into a test tube and sterilized by autoclave) and sterilized glass beads (φ4-5m)
m) 40 to 50 cells were added and shaken well to rinse away the bacterial solution, and then the number of colonies was measured by the serial dilution method to calculate the viable cell count. The remaining one is covered with a petri dish and left standing at 25 ° C. The bacterial solution inoculated by the same operation as above for 6 hours or more was rinsed off to calculate the viable cell count. The obtained results are shown in Table 2. The number of colonies is measured by SC
DLP agar medium was added, and the culture was performed after culturing at 37 ° C. for 48 hours.

[0028]

[Table 2]

The samples obtained in Examples 6 and 7 and Comparative Example 4 were tested and evaluated in the same manner as the above-mentioned antibacterial test. The results obtained are shown in Table 3.

[0030]

[Table 3]

Next, the samples obtained in Examples 8 to 10 and Comparative Example 5 were tested and evaluated in the same manner as the above-mentioned antibacterial test. The obtained results are shown in Table 4.

[0032]

[Table 4]

(3) Ultraviolet Discoloration Resistance Test The coating film obtained in Example 10 is prepared. Next, Example 1
Example 1 except that a commercially available silver ion-supporting zeolite fine powder was added and dispersed in place of the antibacterial composition of the present invention at 0.
A comparative coating film prepared under the same conditions as in 0 is prepared. Each of the above samples was exposed to a sunshine weatherometer (63 ° C., rainfall for 12 minutes, rainfall cycle for 60 minutes), and the color difference was measured after 100 hours and 200 hours, to compare the discoloration properties of both. The results obtained are shown in Table 5.

[0034]

[Table 5]

[0035]

Since the present invention is constructed as described above, it prevents the gas volatilization of antibacterial components which could not be achieved by conventional products of this kind, and keeps the antibacterial effect stable while heating. When used in plastics, paints, etc., it can maintain its function over a long period of time and there is no risk of discoloration due to ultraviolet rays or discoloration due to chemical reaction. It can be widely used for industrial applications and is extremely useful in industry.

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Claims (6)

[Claims] 1. An antibacterial composition comprising silica fine particles, which adsorbs and supports zinc sulfate, as a main component. 2. The antibacterial composition according to claim 1, which is silica fine particles having an average particle size of 1 μm or less. 3. The ratio of zinc sulfate adsorbed and supported on silica fine particles is 10 to 4 relative to 100 parts by weight of silica fine particles.
The antibacterial composition according to claim 1 or 2, which is 0 part by weight. 4. The antibacterial composition according to claim 1, which is for kneading plastics. 5. The antibacterial composition according to claim 1, which is used for adding a paint to be applied to plastics. 6. Zinc sulfate heptahydrate in the form of an aqueous solution is adsorbed and supported on silica fine particles and dried by heating within a temperature range of 40 to 280 ° C., whereby the crystal water structure is changed from heptahydrate to hexahydrate. The method for producing an antibacterial composition according to any one of claims 1 to 5, wherein deionized water is gradually added to a water salt or an anhydrous salt.