JPH1025206A - Antibacterial composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an antibacterial composition which shows antibacterial activity against a variety of bacterial and possesses improved heat-stability and stability to solvents. SOLUTION: This composition is composed of a complex between a quaternary ammonium ion having antibacterial activity and amorphous silicon dioxide. This complex is producible by drying a gel product produced by reacting sodium silicate with an inorganic acid in an aqueous solution containing a quaternary ammonium ion having antibacterial activity followed by isolation and washing with water. The antibacterial composition possesses higher heat-stability than conventional organic antibacterial agents and is stable to a variety of solvents. Consequently, it is usable as an antibacterial binder mixed with various kinds of binders and as an antibacterial processed product by adding it into fibers, papers, films, plastics and inks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel antibacterial composition having an antibacterial activity against various bacteria and molds, and a method for producing the same, and more particularly, to a method which is stable against heat and various solvents. The present invention relates to an antibacterial composition which can be used as an antibacterial functional agent mixed with various additives, or as an antibacterial processed product by being supported on fibers, paper, film, plastic, ink, etc., and a method for producing the same. It is.

[0002]

Conventionally, antibacterial compounds include quaternary ammonium salts such as benzalkonium chloride and cetylpyridinium chloride; alcohols such as ethanol and isopropanol; aldehydes such as formalin and glyoxal; Phenols such as xylenol, carboxylic acids such as sorbic acid and benzoic acid, guanidines such as chlorhexidine and n-dodecylguanidine acetate, and many others are known.

[0003]

However, the above-mentioned antibacterial compounds have poor heat resistance, relatively high vapor pressure, and high solubility in water and other solvents. For these reasons, it is not suitable for use when heating such as kneading into resin or fiber is required, or when trying to maintain the antibacterial effect for a long time in open space or running water. It was appropriate.

[0004] The present invention has been made in view of such conventional problems, and by increasing the heat resistance and decreasing the vapor pressure and solubility of the conventional antibacterial compound, it can be applied to resins and fibers. An object of the present invention is to provide an antibacterial composition which can be kneaded and has a long lasting antibacterial effect, and a method for producing the same.

[0005]

Means for Solving the Problems To achieve the above object, the present inventors have conducted intensive studies and found that a composition obtained by complexing a quaternary ammonium ion having an antibacterial action with amorphous silicon dioxide. However, they have found that the antibacterial action is maintained, and that the thermal stability and the stability to solvents are improved, and the present invention has been accomplished.

That is, the antibacterial composition of the present invention is characterized by comprising amorphous silicon dioxide compounded with a quaternary ammonium ion having an antibacterial action.

The above antibacterial composition of the present invention separates and rinses a gel formed by reacting sodium silicate and an acid in an aqueous solution containing a quaternary ammonium ion having an antibacterial effect, By drying, it can be easily manufactured.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The quaternary ammonium ion having an antibacterial action in the present invention is a monovalent cation in which four carbon bonds are directly bonded to a nitrogen atom. Examples thereof include an alkyltrimethylammonium ion and a dialkyl cation. Dimethylethylammonium ion, alkyldimethylethylammonium ion, alkyldimethylbenzylammonium ion, alkylpyridinium ion, alkylquinolium ion, alkylamidopropyldimethylbenzylammonium ion, benzyldimethyl p-
(1,1,3,3-tetramethylbutylphenoxy) ethylammonium ion and the like. These are usually supplied by quaternary ammonium salts such as chloride, bromide and iodide. These quaternary ammonium ions may be not only one kind but also several kinds together with silicon dioxide to form an amorphous composite.

The sodium silicate used in the production of the amorphous composite includes water glass which is industrially produced in large quantities. On the other hand, the acid is not particularly limited as long as it can neutralize sodium silicate.

In the present invention, the reaction in which a quaternary ammonium ion is complexed with amorphous silicon dioxide is considered as follows. That is, when sodium silicate is neutralized by an acid, a gel of silicon dioxide is formed. At this time, the quaternary ammonium ions present in the reaction system are incorporated into the gel skeleton in the form of ions or silicates to form a complex.

In producing the antibacterial composition of the present invention, a quaternary ammonium salt is allowed to coexist with an aqueous solution of sodium silicate or an aqueous solution of an acid such as sulfuric acid or nitric acid, and these two aqueous solutions are mixed. Let react.
Alternatively, an aqueous solution of sodium silicate and an aqueous solution of an acid such as sulfuric acid and nitric acid may be separately added to the aqueous solution of a quaternary ammonium salt at the same time to cause a reaction. The gel thus obtained is separated, washed with water to remove sodium salt as a by-product of the reaction, and then dried, whereby amorphous silicon dioxide complexed with quaternary ammonium ions, that is, the antibacterial composition of the present invention is obtained. can get.

In the above-mentioned production method, when quaternary ammonium ions are allowed to coexist with an aqueous solution of sodium silicate, a quaternary ammonium salt serving as a supply source is passed through an anion exchange resin or the like to remove anionic species in advance. Alternatively, it is necessary to add sodium hydroxide or the like to a hydroxide state.

[0013]

Next, the present invention will be described in detail with reference to examples. However, these examples are for illustrative purposes only, and the present invention is not limited thereto.

In the antibacterial test in the examples, the minimum inhibitory concentrations (hereinafter abbreviated as MIC) for various bacteria were measured by an agar dilution method. The measurement was performed by the following method.

An agar medium having different concentrations of the test sample powder is prepared in a sterilized petri dish. A certain amount of bacterial solution is placed on each of these media, and cultured at 30 ° C. Then, it is left until there is no change (proliferation or decrease) in the state of the bacteria. Determine the minimum concentration of the test article in the medium in which growth was completely inhibited
Determined as C value.

As a test strain, Staphylococcus aureus
FDA 209P (Staphylococcus aureus), Escherichia coli IFO 3
044 (E. coli), Klebsiella pneumoniae IFO 13277
(Klebsiella), Pseudomonas aeruginosa IFO 3452
(Pseudomonas aeruginosa), Aspergillus niger IFO 6341 (Black Aspergillus),
Penicillium citrinum IFO 6347 (blue mold), Trichoph
yton mentagrophytes IFO 5466 (Trichophyton) was used.

Further, powder X-ray diffraction was performed to confirm that the obtained composite was amorphous, and a differential heat / thermal balance (hereinafter abbreviated as DTA-TG) measurement was performed to confirm the improvement of thermal stability. went.

The quaternary ammonium content was determined by conversion from the total nitrogen content obtained by elemental analysis.

Example 1 Alkylbenzyldimethylammonium ions (alkyl groups: C ₈ H _{17 to} C ₁₈ H ₃₇ ) were used as quaternary ammonium ions having an antibacterial effect, and water glass No. 3 was used as sodium silicate.

9.0 g of alkylbenzyldimethylammonium chloride (benzalkonium chloride) was dissolved in 500 g of sulfuric acid diluted to 2.7%. On the other hand, for Water Glass No. 3, 100 g was diluted with 500 g of water. These two aqueous solutions are mixed, and the formed gel is separated by filtration, washed with water, and dried.
By drying at ℃, the antibacterial composition of the present invention was obtained. The content of the alkylbenzyldimethylammonium ion was 13.5%.

Example 2 Cetyltrimethylammonium ion was used as a quaternary ammonium ion having an antibacterial action, and water glass No. 3 was used as a sodium silicate.

Cetyltrimethylammonium bromide 1
0 g was dissolved in 300 g of sulfuric acid diluted to 3.5%.
Hereinafter, the antibacterial composition of the present invention was obtained in the same manner as in Example 1. The content of cetyltrimethylammonium ion was 13.2%.

Example 3 Cetylpyridium ion was used as a quaternary ammonium ion having an antibacterial effect, and sodium silicate was water glass 2
No. used.

12 g of cetylpyridinium chloride was added to water 2
00g. While stirring this aqueous solution, 3.5 g of a solution obtained by diluting 100 g of water glass No. 2 with 200 g of water was added.
330 g of% hydrochloric acid were added separately and simultaneously. The resulting gel was filtered off, washed with water and dried at 120 ° C. to obtain the antibacterial composition of the present invention. The content of cetylpyridium ion was 19.5%.

Comparative Example (Preparation of Amorphous Silicon Dioxide) 100 g of Water Glass No. 3 was diluted with 300 g of water, and 3.5%
The mixture was mixed with 370 g of hydrochloric acid, the obtained gel was separated by filtration, washed with water, and dried at 120 ° C. to obtain amorphous silicon dioxide.

Antibacterial test: Table 1 shows the results of an antibacterial test conducted on the antibacterial compositions of the present invention obtained in Examples 1, 2, and 3 and the compositions obtained in Comparative Examples. MIC
It can be said that the smaller the value, the stronger the antibacterial activity. However, the amorphous silicon dioxide of the comparative example itself does not show the antibacterial activity even at 1000 ppm, whereas the antibacterial activity of the present invention obtained in Examples 1, 2, and 3 It can be seen that the composition shows an excellent antibacterial effect on various bacteria at a relatively low concentration.

[0027]

Powder X-ray diffraction: It was confirmed by powder X-ray diffraction that the compositions obtained in Examples 1, 2, 3 and Comparative Example were all amorphous. As an example, the powder X-ray diffraction pattern of the antibacterial composition of the present invention obtained in Example 1 is shown in FIG.

DTA-TG measurement: The DTA-TG curve of the amorphous complex of alkylbenzyldimethylammonium ion and silicon dioxide obtained in Example 1 shown in FIG. 2 shows a weight loss due to adsorbed water up to around 120 ° C. , And exothermic peaks at around 260, 330 and 370 ° C. with a weight loss presumably due to the alkylbenzyldimethylammonium ion. DT of alkylbenzyldimethylammonium chloride of FIG.
Compared with the A-TG curve, the temperature at which the weight starts to decrease is higher, and the temperature gradually decreases over a wide area, which confirms that the thermal stability is improved.

Table 2 shows the results of DTA-TG measurements of the antimicrobial compositions of the present invention obtained in Examples 1, 2 and 3 and the quaternary ammonium salt used in each Example. It is indicated by the temperature of an endothermic or exothermic peak accompanied by a weight loss based on ions. The temperature of the endothermic or exothermic peak accompanying weight reduction based on the quaternary ammonium ion of the antibacterial composition of the present invention obtained in Examples 1, 2, and 3 was changed according to the quaternary ammonium used in each Example. It can be seen that the thermal stability is improved by being recognized at a higher temperature as compared with the salt.

[0031]

The antimicrobial compositions of the present invention obtained in Examples 1, 2, and 3 were further subjected to a solvent resistance test to examine the stability to various solvents. In the solvent resistance test, each of the antibacterial composition samples was put into a solvent at 5 wt%, and the mixture was gently stirred by hand. The container was sealed so that the solvent did not volatilize, and allowed to stand indoors for 10 days. The MIC value was obtained by filtering, collecting, and conducting an antibacterial test. Table 3 shows the results.
Table 3 shows that the antimicrobial composition of the present invention has sufficient solvent resistance.

[0033]

[0034]

As described above, the antibacterial composition of the present invention has higher heat stability and is less soluble in various solvents than conventional organic antibacterial agents. It is expected to have a very wide application range, such as being able to impart antibacterial performance to base materials by being added to and processed into base materials such as plastics, paper, and fibers, as well as being used as granules. it can.

[Brief description of the drawings]

FIG. 1 is a powder X-ray diffraction pattern of amorphous silicon dioxide complexed with an alkylbenzyldimethylammonium ion obtained in Example 1.

FIG. 2 is a DTA-TG curve of amorphous silicon dioxide complexed with alkylbenzyldimethylammonium ion obtained in Example 1.

FIG. 3 is a DTA-TG curve of alkylbenzyldimethylammonium chloride (benzalkonium chloride).

Claims (2)

[Claims] 1. An antibacterial composition comprising amorphous silicon dioxide compounded with a quaternary ammonium ion having an antibacterial action. 2. An antibacterial property characterized by separating, washing and drying a gel-like substance produced by reacting sodium silicate with an acid in an aqueous solution containing a quaternary ammonium ion having an antibacterial action. A method for producing the composition.