JPH04234303A - Production of antifugal ceramics - Google Patents

Abstract

PURPOSE:To provide the title ceramics not causing dissolving out the antifungal metal carried thereon into water, stable to heat, giving antifungal performance for a long period of time, usable by its dispersing homogeneously in base materials such as synthetic resins, fibers and coatings, etc. CONSTITUTION:(A) At least one ceramics selected from calcium phosphate, calcium hydrogenphosphate, calcium carbonate, calcium silicate and hydroxyapatite is added to (B) an aqueous solution containing at least one water-soluble salt selected from antifungal metal salts, i.e., silver, copper and zinc salts, followed by treatment under heating (pref. at >=80 deg.C), and the resulting precipitate is collected, thus obtaining the objective antifungal ceramic with 0.01-20wt.% of the antifungal metal(s) carried on the ceramics.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing antibacterial ceramics, and more specifically, the present invention relates to a method for manufacturing antibacterial ceramics, and more specifically, the present invention relates to a method for manufacturing antibacterial ceramics. The present invention relates to a method for producing antibacterial ceramics, which involves adding a water-soluble salt of Antibacterial metals supported on ceramics do not dissolve into water, so they are safe and have a wide range of applications.

0002

BACKGROUND OF THE INVENTION It has been known for a long time that metals such as silver, copper and zinc and their salts have strong antibacterial and antifungal properties, and various methods of utilizing them have been studied. However, when mixed with base materials such as synthetic resins, fibers, and paints as metals and salts, problems arise such as dispersibility in the base materials and elution of metal ions from the base materials, so they cannot be used widely. There wasn't.

[0003] In recent years, as a method of utilizing the antibacterial properties of these antibacterial metals, a method has been proposed in which antibacterial metal salts are treated with highly safe ion exchange ceramics and the antibacterial metals are supported on the ceramics through ion exchange. . For example, JP-A-60-181002 discloses that antibacterial metal ions are added to zeolite, and JP-A-2-180270 discloses that
Discloses antibacterial ceramics in which antibacterial metal ions are supported on hydroxyapatite through ion exchange. These antibacterial ceramics have reduced elution of supported antibacterial metal ions into water and improved dispersibility into substrates, so they can be used relatively safely and over a wide range of areas. However, depending on the medium used with these substances, such as water, antibacterial metal ions may be eluted into the medium, so not all media can be used safely.

[0004] Therefore, we attempted to use antibacterial metal ions safely without leaching them into the medium, and we developed ceramics supported with antibacterial metals by 80%.
It was confirmed that antibacterial metal ions do not elute from the ceramics into water by firing at 0°C or higher, and a patent application was filed for the method as Japanese Patent Application No. 2-226738. Firing prevents the elution of antibacterial metal ions into water, making it possible to use antibacterial ceramics more safely, but there are problems such as the need for a firing furnace, high firing costs, and the number of days required for manufacturing. It cannot be called industrial.

[0005]

[Problems to be Solved by the Invention] The present invention provides ceramics supported with antibacterial metals, that is, silver, copper and/or zinc, in which the supported antibacterial metal ions do not dissolve into water. Regardless, the object of the present invention is to provide a method for manufacturing antibacterial ceramics that can be manufactured simply and without requiring the conventional firing process.

[0006]

[Means and effects for solving the problem] As mentioned above, ceramics such as antibacterial zeolite and hydroxyapatite obtained by ion-exchanging antibacterial metal ions are highly safe and have good dispersibility in base materials. Although it is a good antibacterial material and easy to use, it cannot always be used safely because the ion-exchanged antibacterial metal ions may gradually dissolve into the medium after long-term use. On the other hand, ceramics supported with antibacterial metals and/or metal salts were
By firing at a temperature of 00°C or higher, antibacterial metal ions will not be eluted into water, but a firing process is required, which complicates the manufacturing process and increases costs.

[0007] Accordingly, as a result of investigating a method for inexpensively producing antibacterial metal-supported ceramics that do not elute antibacterial metal ions into water without firing them, we were able to establish the desired production method. That is, a predetermined amount of ceramics is added to an aqueous solution containing a predetermined amount of at least one of water-soluble antibacterial metal salts, i.e., silver, copper, and zinc salts and stirred, and the solution is heated for several hours, preferably at 80°C. After the above heat treatment, the resulting precipitate was collected, thoroughly washed with distilled water, dried and pulverized to obtain the desired antibacterial ceramics.

The ceramics used in the present invention are selected from ceramics that are highly safe and have a large adsorption amount of antibacterial metal water-soluble salts, and are selected from calcium phosphate, calcium hydrogen phosphate, calcium carbonate, calcium silicate, and hydroxyapatite. At least one type of calcium-based ceramic is more preferable and most suitable. Hydroxyapatite has a composition of Ca10(PO4)6(OH)2 and is generally synthesized from calcium salts and phosphates, but its synthesis requires considerably complicated steps. However, calcium phosphate salts with a Ca/P molar ratio of 1.4 to 1.8 are more easily synthesized than calcium salts and phosphates, and the resulting salts exhibit similar properties to hydroxyapatite, so they are not similar to hydroxyapatite. Similarly, it can be used in the present invention as a ceramic. Therefore, calcium phosphate salts having a molar ratio of Ca/P of 1.4 to 1.8 are also included in the present invention as hydroxyapatite. Calcium silicate is a general term for compounds composed of a combination of calcium oxide and silicon dioxide, and includes, for example, calcium metasilicate, calcium orthosilicate, tricalcium silicate, and the like. The antibacterial metal salts used in the present invention are salts of silver, copper, and zinc, such as water-soluble salts such as copper nitrate, zinc nitrate, silver nitrate, and zinc sulfate.

[0009] Ceramics are added to these soluble metal salt aqueous solutions, heated while stirring, preferably heated to 80°C or higher, and after heating and stirring for several hours, the formed precipitate is collected and thoroughly washed with distilled water. After washing, dry and crush to obtain the desired antibacterial ceramics. The amount of water-soluble antibacterial metal salt used is arbitrarily selected depending on the type of ceramics used. However, for example, if hydroxyapatite is used as the ceramic and a large amount of antibacterial copper salt is used, the copper salt of Cu2(PO4)(OH) will precipitate, which is not preferable. Therefore, the use of large amounts of antibacterial metal salts should be avoided, and the amount used must be less than the saturated adsorption amount of the ceramic used, preferably less than 20% by weight of the ceramic. On the other hand, in consideration of the antibacterial power of the antibacterial ceramics that can be obtained, the amount supported must be 0.01% or more by weight based on the ceramics. Also, when using hydroxyapatite as ceramics,
When producing hydroxyapatite from calcium salts and phosphates by a conventional method, after allowing a water-soluble antibacterial metal salt to coexist, this aqueous solution is heated, preferably at a temperature of 80°C or higher, and the precipitate is collected. Antibacterial hydroxyapatite can also be obtained by thoroughly washing with distilled water, drying and crushing.

The exact composition of the antibacterial ceramic thus obtained is not clear. However, for example, when hydroxyapatite is used as a ceramic and zinc nitrate is used as an antibacterial metal salt, heat treatment causes partial metathesis of hydroxyapatite and zinc nitrate, resulting in C
It is thought that zinc-supported hydroxyapatite having the composition a10-XZnX (PO4)6(OH)2 is partially produced. That is, the antibacterial ceramic obtained by the treatment method of the present invention has an antibacterial metal salt strongly supported on the ceramic by chemical adsorption, and also contains a product in which calcium in the ceramic is partially replaced with an antibacterial metal. It is estimated that there are.

[0011] The present invention will be specifically explained below with reference to Examples. The metal content in the example was determined by dissolving the final product in nitric acid, diluting the solution with distilled water, and measuring the amount of metal ions using an atomic absorption spectrophotometer. Example 1) Hydroxyapatite 1.0 in 10L of distilled water
Kg and 0.16 g of silver nitrate are added and stirred. Heat this solution at 80° C. for 2 hours while stirring. After the temperature of the solution drops to about room temperature, the product is filtered and washed. Thereafter, it was dried and crushed to obtain antibacterial hydroxyapatite carrying approximately 0.01% silver. (1-1)

001
2] Example 2) 1.0Kg of calcium carbonate in 10L of distilled water
, add 4 g of copper nitrate and stir. Heat this solution at 80° C. for 1 hour while stirring. The solution is allowed to stand until the next day, and then the product is filtered and washed. Thereafter, it was dried and crushed to obtain antibacterial calcium carbonate carrying about 0.1% copper. (2-1)

Example 3) Add 1.0 kg of hydroxyapatite, 8 g of silver nitrate, and 23 g of zinc nitrate to 10 liters of distilled water and stir. Heat this solution at 80° C. for 2 hours while stirring. After the temperature of the solution drops to about room temperature, the product is filtered and washed. Thereafter, it was dried and crushed to obtain antibacterial hydroxyapatite carrying about 0.5% silver and about 0.5% zinc. (3-1)

Example 4) Add 1 part of calcium silicate to 10 liters of distilled water.
．． Add 0 kg, 20 g of copper sulfate, and 44 g of zinc sulfate and stir. Heat this solution at 100° C. for 3 hours while stirring. After the temperature of the solution drops to about room temperature, the product is filtered and washed. After that, it is dried and crushed to produce approximately 0.0% copper.
Antibacterial calcium silicate carrying about 1% of zinc was obtained. (4-1)

Example 5) Add 1.0 kg of hydroxyapatite and 117 g of copper nitrate to 10 liters of distilled water and stir. Heat this solution at 80° C. for 2 hours while stirring. After the temperature of this solution drops to about room temperature, the product is filtered,
Wash. Thereafter, it was dried and crushed to obtain antibacterial hydroxyapatite carrying approximately 3% copper. (5-1)

0
Example 6) Add 1.0 kg of calcium monohydrogen phosphate, 192 g of copper nitrate, and 23 g of zinc nitrate to 10 liters of distilled water and stir. Heat this solution at 100° C. for 30 minutes while stirring. The solution is allowed to stand until the next day, and then the product is filtered and washed. Thereafter, it was dried and pulverized to obtain antibacterial calcium monohydrogen phosphate carrying about 5% copper and about 0.5% zinc. (6-1)

Example 7) Add 1.0 kg of hydroxyapatite and 395 g of copper sulfate to 10 liters of distilled water and stir. Heat this solution at 100° C. for 2 hours while stirring. After the temperature of the solution drops to about room temperature, the product is filtered and washed. Thereafter, it was dried and crushed to obtain antibacterial hydroxyapatite carrying approximately 10% copper. (7-1)

Example 8) Add 1.0 kg of tricalcium phosphate, 308 g of copper nitrate, and 552 g of zinc nitrate to 10 liters of distilled water and stir. Heat this solution at 100° C. for 2 hours while stirring. The solution is allowed to stand until the next day, and then the product is filtered and washed. After that, it is dried and crushed to remove about 8% copper.
Antibacterial tricalcium phosphate carrying about 12% zinc was obtained. (8-1)

Example 9) Metal ion elution test Examples 1) to 8)
Each sample was added to 100 ml of distilled water, stirred for 24 hours, and then the metal ions in the solution were measured using an atomic absorption spectrophotometer to determine the elution amount. In addition, powders (1-2, 2-2, 3-2, 4-2, 5-2, 6-
2, 7-2, 8-2) were used for comparison.

[Table 1] As described above, no elution of metal is observed in the metal-containing ceramics produced by the method of the present application.

Example 10) Antibacterial activity test A bacterial solution containing 2.9 x 103 Trichophyton was added to a phosphate buffer solution containing 1% by weight of each of the samples from Examples 1) to 8). The antibacterial activity against bacteria was measured. the result,
In all cases, no bacteria were detected within 24 hours.

[0021]

[Effects of the Invention] The antibacterial ceramics obtained by the method of the present invention have antibacterial metals eluted in water below the detection limit, retain antibacterial properties for a long period of time, are stable against heat, and have antibacterial properties. No loss of color, no discoloration, 50% by weight to other materials
Hereinafter, sufficient antibacterial activity is exhibited by preferably adding about 0.1 to 10% by weight. Furthermore, since it has good dispersibility in organic substances, it is easy to obtain a material with homogeneous antibacterial properties even when dispersed in synthetic resins, paints, adhesives, etc. The present inventors filed a patent application in Japanese Patent Application No. 2-226738 for antibacterial ceramics that do not elute antibacterial metal ions into water by firing at 800°C or higher. "Water-absorbing sheet or film"
(Patent Application No. 2-258854), “Polyolefin resin molded article having antibacterial and antifungal properties and its manufacturing method” (
Patent Application No. 2-263037), “Aquatic Organism Fouling Prevention Agent”
(Patent Application No. 2-263038), “Polymer Foam Having Antibacterial and Antifungal Properties and Method for Producing the Same” (Patent Application No. 2-26
No. 3753), “Fiber materials and fibers with antibacterial properties” (
Patent application No. 2-279294) and "Mold-resistant joint material" (Japanese patent application No. 2-279295). The antibacterial ceramic obtained by the manufacturing method of the present invention has antibacterial properties, safety, and properties equivalent to those of the above-mentioned fired antibacterial ceramic, and the manufacturing process is simple. Therefore, it is possible and preferable to use the antibacterial ceramics obtained by the manufacturing method of the present invention instead of the fired antibacterial ceramics described above.

Claims (3)

[Claims] Claim 1: An aqueous solution containing at least one ceramic selected from calcium phosphate, calcium hydrogen phosphate, calcium carbonate, calcium silicate, and hydroxyapatite and at least one water-soluble salt selected from silver, copper, and zinc. 1. A method for producing antibacterial ceramics, the method comprising adding a precipitate to the material and collecting the precipitate after heat treatment. 2. The method for producing antibacterial ceramics according to claim 1, wherein the amount of water-soluble metal salts of silver, copper, and zinc is 0.01 to 20% by weight based on the ceramic. 3. The method for producing antibacterial ceramics according to claim 1 or 2, wherein the temperature of the heat treatment is 80° C. or higher.