JPH0543414A - Production of antibacterial mildew-proofing composition - Google Patents

Abstract

PURPOSE:To provide a process for producing an antibacterial and mildew- proofing composition effective for imparting antibacterial and mildew-proofing property to the surface of a resin by blending, giving an antibacterial and mildew-proofing material having high thermal stability durable to the heat in the molding of the resin without causing the discoloration of the resin and keeping the antibacterial and mildew-proofing activity over a long period while preventing the environmental pollution. CONSTITUTION:The antibacterial and mildew-proofing material to be used in the objective composition is produced by adding a weak acid or weak acid base for pH adjustment and a reducing agent such as sulfite and bisulfite as a stabilizer to a thiosulfate-silver complex salt produced by reacting a silver halide with a thiosulfate. The material is quickly adsorbed on a silica gel carrier and the surface is coated with a coating material such as an organic silicon compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition carrying an antibacterial and antifungal material, and more particularly to a method for producing an antibacterial and antifungal composition having silica gel as a carrier and having improved stability.

[0002]

2. Description of the Related Art Conventionally, as an antibacterial and antifungal composition, an inorganic type and an organic nitrogen type have been known. The latter has a very high bactericidal performance but is unknown from the viewpoint of toxicity to human body and environmental pollution. There are many parts and the safety aspects are being considered.

[0003]

With the increasing use of synthetic resin products in recent years, contamination of the surface of synthetic resins by bacteria has become a problem. The above-mentioned organic antibacterial agent is used in order to volatilize and elute the bactericidal component in the resin and sterilize the resin surrounding environment, but some organic nitrogen antibacterial agents passed through this surface. There is a problem that the antibacterial agent contained in the liquid causes pollution of wastewater environment and also affects the activated sludge during sewage treatment.

Therefore, there is a need for an antibacterial and antifungal composition which has an antibacterial effect on the surface of the resin, is unlikely to cause environmental pollution, and does not change the properties of the synthetic resin which has been subjected to the antibacterial and antifungal treatment.

Therefore, recently, an antibacterial and antifungal composition mainly containing Ag salt has been in the spotlight, but Ag salt material is discolored by visible light and ultraviolet light as well known as a photographic light-sensitive material. -It has a coloring property, and there was a problem in applying it to white hygiene products.

[0006]

SUMMARY OF THE INVENTION The present invention uses a silver halide such as silver chloride or silver bromide as a starting material, and dissolves the above silver halide in an aqueous sodium thiosulfate solution to form a thiosulfato silver complex salt. To use. After using silica gel as a carrier and adsorbing the silver complex salt capable of being adsorbed on the silica gel and having antibacterial and antifungal properties as an antibacterial and antifungal material,
The present invention provides a method for producing an antibacterial and antifungal composition in which a part or all of the surface of the silica gel is coated with a coating material such as an organosilicon compound.

[0007]

[Function] When silver thiosulfato silver complex salt is formed by using silver chloride as a starting material, and this is used as an antibacterial and antifungal material, a pH adjusting agent and a reducing agent are added thereto, and the silver complex salt is further supported on silica gel. Improves stability of silver complex salt.

[0008] By using silica gel as a carrier, there is a sustained release effect of the antibacterial and antifungal material adsorbed thereon, and by providing a coating material on it, the thermal stability of the antibacterial and antifungal material is increased. . This means that the antibacterial and antifungal composition of the present invention is dispersed in a synthetic resin, and the thermal stability of the antibacterial and antifungal material against heat during resin molding when the surface of the synthetic resin has antibacterial and antifungal properties. It not only increases the viscosity of the resin, but also suppresses the color change over time of the resin.

[0009]

EXAMPLES Examples of the present invention will be described in detail below. Pure water 3
To a solution of 8 g of sodium thiosulfate in 0 ml, 200 mg of silver chloride is dissolved in a light-shielded room temperature environment to obtain a silver complex salt solution. 40 mg of sodium sulfite and 40 mg of sodium hydrogen sulfite are sequentially dissolved in this solution. Finally, 40 mg of citric acid is added to prepare a weakly acidic aqueous solution. 5 g of a B-type silica gel carrier having an average particle size of about 2.6 microns described in "JISZ 0701 packaging silica gel desiccant" dried at 180 ° C for 2 hours or more was added to the above-prepared aqueous solution and dispersed well. , Adsorb. After the adsorption, it is vacuum dried at about 50-60 ° C. and pulverized to obtain a material in which the above-mentioned antibacterial and antifungal material is adsorbed on the carrier.

100 parts by weight of the carrier having adsorbed the above-mentioned antibacterial and antifungal material was dispersed in a liquid obtained by mixing 100 parts by weight of tetramethoxysilane with 100 parts by weight of ethyl alcohol, and then 20 parts by weight of pure water was added to add water. The antibacterial and antifungal composition is obtained by decomposing, coating a part or all of the upper surface of the carrier on which the antibacterial and antifungal material is adsorbed, and drying.

The antibacterial and antifungal composition produced by the method of the above-mentioned example was uniformly dispersed in 100 parts by weight of an unsaturated polyester resin to form a resin molded product by uniformly dispersing 3 parts by weight of the antibacterial and antifungal composition. Then, an antifungal test and an antibacterial test as shown below were conducted. As a result, the antibacterial spectrum shown in the table below was obtained, and practical antibacterial and antifungal performance was confirmed. This anti-mold test is a mold resistance test (JIS Z
2911) according to the halo test method based on the mildew proof test for textiles. The molds used were Cladosporium cladosporioides, Chaetomium globosum, Penicillium citrinum, Aspergillus niger, and the evaluation was 14
I did it a day later. The antibacterial test was carried out by using the halo test method using Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, and the evaluation was carried out 7 days later.

[0012]

[Table 1]

In the above embodiment, in order to prepare the silver thiosulfato complex salt, a water-soluble silver salt such as silver nitrate instead of silver acetate, a sulfite salt such as potassium sulfite or ammonium sulfite, sodium bisulfite instead of sodium sulfite. In place of sodium thiosulfate such as potassium bisulfite, potassium metasulfite, ammonium bisulfite alone or in a mixture, water-soluble thiosulfate such as ammonium thiosulfate in place of tetramethoxysilane, and tetraethoxysilane in place of tetramethoxysilane. The same result was obtained using an organosilicon compound such as silane.

Further, as the coating material, in addition to the above-mentioned organic silicon compound, a coating material such as wax or stearic acid compound can be applied.

Further, in order to improve the stability of the silver complex salt, a reducing agent such as sulfite or bisulfite, an inorganic acid for adjusting pH, an organic acid, or an antibacterial and antifungal material containing a salt thereof is added. Silica gel having a large carrying capacity is dispersed in an aqueous solution to deposit an antibacterial and antifungal material on the surface of the carrier.

Further, the carrier for adsorbing the above-mentioned antibacterial and antifungal composition is made of a light-transmitting material having a refractive index similar to that of a synthetic resin, and has a relatively small amount of moisture absorbed in a low humidity region and a total amount of adsorption. By using the B-type silica gel powder described in JIS, which has a large size, it is possible to impart antibacterial and antifungal performance to the surface of the synthetic resin without coloring the synthetic resin.

[0017]

As described above, the antibacterial and antifungal composition according to the production method of the present invention maintains the antibacterial and antifungal effect for a long period of time by the sustained release effect of the adsorbed antibacterial and antifungal material by the silica gel carrier. In addition, it has stability against light and heat, and is unlikely to cause environmental pollution. And the color change over time is also suppressed.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mariko Tomita 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Atsushi Nishino 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A solution obtained by sequentially dissolving a silver halide, a pH adjusting agent comprising one or more kinds of acids or salts of the acids and one or more kinds of reducing agents in an aqueous sodium thiosulfate solution. A method for producing an antibacterial and antifungal composition, which comprises coating a part or all of the surface of the silica gel with a coating material after adsorbing on a silica gel carrier and drying.