JPH07300339A - Antifungal glass composition - Google Patents

Abstract

PURPOSE:To easily obtain the subject composition capable of stably containing much Ag<+> ions and wide in sufficient antivacterial nature-manifesting range according to its use by regulating its dissolution rate in water. CONSTITUTION:This antibacterial glass composition comprises 40-55mol% of P2O5, 30-60mol% of CaO plus MgO, 0-4mol% of SiO2 plus Al2O3, 0-15mol% of Li2O plus B2O3, 0-5mol% of Na.0 plus K2O, 0-30mol% of ZnO plus BaO [where, (CaO+MgO+ZnO+BaO) totaling 30-60mol%], 0-5mol% of PbO, and 0.03-5mol% of Ag2O.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a glass composition having excellent antibacterial and antifungal properties.

[0002]

It is well known that monovalent silver ion (Ag ⁺ ) is toxic to lower organisms such as microorganisms. Here, the microorganisms mean bacteria, fungi, and viruses in a narrow sense, and further include protozoa, algae, and the like in a broad sense. In the present specification, showing toxic effects (including antibacterial effects) to the above-mentioned microorganisms is simply referred to as having antibacterial properties.

Many methods for imparting antibacterial properties by incorporating silver ions into a soluble glass have been proposed. As such a soluble glass, a borosilicate type glass containing SiO ₂ , B ₂ O ₃ as a main component and a phosphoric acid type glass containing P ₂ O ₅ as a main component are known. For example, for borosilicate soluble glass
An antibacterial water treatment agent containing Ag ⁺ ions (Japanese Patent Publication No. 4-50878), a phosphoric acid-based soluble glass containing Ag ⁺
There is an antibacterial resin-added glass composition containing an ion (JP-A-4-338129).

[0004]

Since the antibacterial property of the silver-containing glass is mainly represented by Ag ⁺ ions, the glass composition is preferably a composition in which silver can stably exist as ions. The stability of Ag ⁺ ions in glass is determined by the higher acidity of the bond between the cation forming the glass network and oxygen, that is, Si-O <B-O <P-O.
Therefore, a large amount of Ag ⁺ ions can be stably contained in the order of silicic acid type <borosilicate type <phosphoric acid type (for example, Ceramic Industry Association, 88 [8], 459 (1980)).

However, although the borosilicate glass can contain a larger amount of Ag ⁺ ions than the silicate glass, the Ag ⁺ ion stability in the glass is not so high, and when it is combined with an organic material, Or when mixed with paint and applied to the surface of other articles for use,
Ag ⁺ ions in the glass are easily reduced by heat treatment or UV irradiation to cause coloring. Further, the amount of silver that can be contained as ions in the borosilicate glass is at most about 0.5 mol%, and when it is used in the form of powder or fiber added to other materials, the whole material is used. Looking at, the content of Ag ⁺ ions may be low and the antibacterial action may not be sufficient.

On the other hand, in phosphoric acid type glass, A
The g ⁺ ion is very stable and can be contained in an amount of several mol% or more. Further, it is hard to be reduced and discolored even by a heat treatment for forming a composite with an organic material or by irradiation with ultraviolet rays. JP-A-4-338129
Paying attention to such a phenomenon, as a glass composition which hardly causes discoloration when added to a synthetic resin, P ₂ 0 ₅ 45 to 75 mol% CaO + MgO 35 to 55 mol% Na ₂ O + K ₂ O 0 to 5 mol% A phosphoric acid-based glass composition represented by SiO ₂ + Al ₂ O ₃ 5 to 20 mol% Ag ₂ O 0.1 to 5 wt% is disclosed. However, the glass composition containing an alkaline earth phosphate as a main component disclosed herein (1) requires a relatively high temperature for melting, and (2) has a relatively low dissolution rate in water. Since the elution rate of silver ions is small, silver ions can be contained in a large amount, but the antibacterial properties cannot be sufficiently expressed. (3) It is possible to adjust the dissolution rate in water according to the application. There is a problem that the range is narrow.

The present invention is capable of stably containing a large amount of Ag ⁺ ions based on the above problems of the prior art,
It is an object of the present invention to provide a glass composition which is relatively easy to produce and has a wide range in which sufficient antibacterial properties can be exhibited depending on the application by adjusting the rate of dissolution in water.

[0008]

That is, the glass composition of the present invention is characterized by being in the following range expressed in mol%. P ₂ 0 ₅ 40 to 55% CaO + Mg0 30 to 60% SiO ₂ + Al ₂ O ₃ 0 to 4% Li ₂ O + B ₂ O _{3 0 to} 15% Na ₂ O + K ₂ O 0 to 5% ZnO + BaO 0 to 30% However, (CaO + Mg0 + ZnO + BaO) ) Total 30 to 60% PbO 0 to 5% Ag ₂ O 0.03 to 5%

Since the antibacterial glass composition of the present invention is mainly composed of a phosphoric acid system in which the acidity of the bond between the cation forming the glass network and oxygen is high and Ag ⁺ ions can exist stably, It is possible to stably contain a large amount of Ag ⁺ ions. Further, by controlling the contents of SiO ₂ and Al ₂ O ₃ which deteriorate the meltability of the phosphoric acid type glass to a small amount, it is possible to relatively easily melt the glass.

Further, the antibacterial glass composition of the present invention suppresses the content of Al ₂ O ₃ which is a component for reducing the dissolution rate of phosphoric acid glass in water to a small amount, so that the small amount of itself can be used. Adjustment of the content in the range or other components such as P ₂ O ₅ , MgO, CaO, BaO, ZnO
The rate of dissolution in water can be controlled by adjusting the content of such as, and the expression of antibacterial properties can be adjusted according to the application. Further, the antibacterial glass composition of the present invention is realized by a combination of powdery phosphate raw materials whose composition is inexpensive as a glass raw material so that the raw materials can be easily mixed and melted and the product can be supplied at a low cost. It is within the range.

The reasons for limiting each component in the above composition range are as follows. That is, if P ₂ O ₅ is less than 40 mol%, the glass tends to be devitrified, and if it is more than 55 mol%, P ₂ O ₅ is insufficient in the combination of only powdery phosphate raw materials, and the mixture and melting are caused. However, liquid phosphoric acid or P ₂ O ₅ having a very high hygroscopic property is inevitably used as a raw material.

When the content of CaO + Mg0 is less than 30 mol%, it is difficult to realize a combined composition of only powdery phosphate raw materials, and when it is more than 60 mol%, P
_The content of ₂ O ₅ is less than 40 mol% and the glass tends to devitrify. In addition, when only MgO is used among the components of CaO + Mg0, the dissolution rate of glass in water becomes smaller than when only CaO is used, and the water resistance can be controlled by adjusting the content of other components. Since the range is narrowed,
It is desirable to use only CaO or increase the proportion of CaO so that the molar ratio of CaO / (CaO + Mg0) is 70% or more.

Al ₂ O ₃ is not an essential component because it deteriorates the melting property of glass as described above, and if too much is added, the dissolution rate of glass in water becomes too small. It is a component whose dissolution rate in water can be adjusted. Because the same function as SiO ₂ also Al ₂ O _3, the upper limit of the sum of _{(SiO 2 + Al 2 O 3} ) is 4 mol% desirably 3 mol%.

Li ₂ O and B ₂ O ₃ are not essential components, but both are components capable of improving the meltability of glass without deteriorating the stability of silver ions. Li ₂ O and B ₂ The total amount of ₂ O ₃ can be added in the range of 15 mol% or less. Since these components reduce the dissolution rate of glass in water, the solubility in water becomes too low when the content exceeds 15 mol%. Further, since these raw materials are expensive, the cost of the product increases when the amount thereof increases. Although ZnO and BaO are not essential components, they are components that improve the melting of the glass without deteriorating the stability of silver ions, and the total amount of ZnO and BaO can be added in the range of 30 mol% or less. . Further, Zn ²⁺ is a component which is inferior to Ag ²⁺ but similarly exhibits antibacterial properties and has an effect of improving the antibacterial activity of glass. Further, if the total amount of (CaO + Mg0 + ZnO + BaO) is too large, the P ₂ O ₅ content will be less than 40 mol% and the glass will be easily devitrified, so these total amounts must be 60 mol% or less. Further, PbO may be contained in an amount of 5 mol% or less. Ag ₂ O is
If it is less than 0.03 mol%, the antibacterial property is weakened, and if it exceeds 5 mol%, metallic silver that does not contribute to the antibacterial property is likely to be produced, and the cost of the product is increased because silver is expensive.

[0015]

EXAMPLES The compositions of the examples shown in Table 1 and the comparative examples shown in Table 2 were adjusted so that Ca, Mg phosphates or carbonates, and optionally Li, Na phosphate compounds or carbonates, SiO ₂ , Al ₂ O ₃ , aluminum phosphate, H ₃ BO ₃ , BaCO ₃ , ZnO, zinc metaphosphate,
A batch was prepared using AgNO ₃ as a raw material. This batch was placed in a Pt crucible, melted at 1300 ° C. for 2 hours, cast on a stainless steel plate, shaped into a plate, and then gradually cooled.
The batch having the composition of this example could be composed only of powdery raw materials, and could be mixed and melted as in the case of ordinary silicic acid-based or borosilicate-based glass. Next, the obtained glass was examined for metal silver deposition, water resistance, antibacterial properties, and discoloration during resin mixing. The results are shown in Table 1 and Table 2.
Shown in the lower row. Among the comparative examples shown in Table 2, 1 and 2 are typical compositions of antibacterial borosilicate glass, 3 to 5 are compositions included in the claims of the above-mentioned JP-A-4-338129, and 6 to
10 is a composition outside the scope of the claims of the present invention.

The deposition state of metallic silver was measured by irradiating a halogen lamp on the obtained plate-shaped glass, counting the number of metallic silver of 10 μm or more per 100 g of the glass. ◯, x when 100 or more

Water resistance is defined by the Japan Optical Glass Industry Association standard (JO
GIS) "Method for measuring chemical durability of optical glass (powder method) 06-1975". This method
A powder having a particle size of 420 to 590 μm was collected from the crushed glass, washed with acetone to remove fine powder,
It is a method in which the specific gravity g is immersed in 100 ml of boiling water for 1 hour, and the weight loss is measured after drying. In order for silver-containing glass to exhibit antibacterial properties, the glass must be dissolved in water to some extent and silver ions must be eluted, and if the dissolution rate is too fast, durability or antibacterial durability will be poor, The weight loss according to the present test method requires 0.2 to 60% solubility in water, and a more preferable solubility is 1.0 to 40%.

The antibacterial property was evaluated simply as follows. 10% by weight of glass pulverized to 105 μm or less was added to an organopolysiloxane-based binder, and this was sprayed onto a glass plate surface of 5 cm square and 1 mm thick, and dried to obtain a sample. This sample was placed on an agar medium, and a spore suspension containing about 1 × 10 ⁵ spores of Aspergius terreus, which is a mold, was sprayed on the sample, which was then covered with a constant temperature of 30 ° C. After culturing in the tank for 1 week, the growth of mold was observed. The evaluation was ⊚ when no growth of Aspergius terreus was observed on the glass surface, ◯ when the growth range of Aspergius terreus was 1/3 or less of the glass surface, and 1/3 or more of the glass surface. When Aspergius terreus was grown in, it was shown as x.

The discoloration at the time of resin mixing is to mix the same amount of powdery polyethylene by weight and glass powder of 105 μm or less,
This was placed in an oven maintained at 200 ° C., heated for 30 minutes, taken out of the furnace and cooled, and it was evaluated by whether or not the melted polyethylene was discolored. The evaluation was indicated by ⊚ when no discoloration was observed, ∘ when the discoloration was slight, and × when the discoloration was remarkable.

[0020]

[Table 1] Examples (mol%) ================================== 1 2 3 4 5 6 7 8 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− P ₂ O ₅ 49.7 44.0 42.5 49.0 49.0 50.0 52.5 48.5 MgO 50.0 55.0 46.5 40.0 0 0 0 8.0 CaO 0 0 0 0 49.5 48.0 43.5 40.0 Al ₂ O ₃ 0 0 0 0 0 1.0 3.0 1.0 B ₂ O ₃ 0 0 10.0 0 0 0 0 0 Li ₂ O 0 0 0 10.0 0 0 0 0 Ag ₂ O 0.3 1.0 1.0 1.0 1.5 1.0 1.0 2.5 Precipitation of metallic silver ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Water resistance (%) 4.0 1.5 0.5 0.3 20.0 11.5 4.7 2.3 Antibacterial property ○ ◎ ○ ○ ◎ ◎ ◎ ◎ ◎ Resin coloring ◎ ◎ ◎ ○ ◎ ◎ ◎ ◎ ○ ====================================

Example (mol%) ========================================== 9 10 11 12 12 13 14 − −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− P ₂ O ₅ 48.0 44.5 49.5 49.5 49.5 48.5 CaO 48.0 44.5 39.5 46.5 46.5 48.5 BaO 0 10.0 0 0 0 0 ZnO 0 0 10.0 0 0 0 SiO ₂ 3.0 0 0 0 0 0 Na ₂ O 0 0 0 3.0 0 0 K ₂ O 0 0 0 0 3.0 0 PbO 0 0 0 0 0 2.0 Ag ₂ O 1.0 1.0 1.0 1.0 1.0 1.0 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Metallic silver deposition ◎ ◎ ◎ ◎ ◎ ◎ ◎ Water resistance (%) 9.5 21.7 15.1 24.8 31.2 18.5 Antibacterial property ◎ ◎ ◎ ◎ ◎ ◎ ◎ Resin coloring ◎ ◎ ◎ ○ ○ ◎ ======================= ============

[0022]

[Table 2] Comparative example (mol%) =================================== 1 2 3 4 5 6 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− SiO ₂ 37.5 36.8 0 0 10.0 0 P ₂ O ₅ 0 0 49.5 50.0 50.0 35.0 MgO 0 0 43.5 39.0 0 0 CaO 0 0 0 0 39.0 50.0 Al ₂ O ₃ 0 0 6.0 10.0 0 0 B ₂ O ₃ 47.0 46.8 0 0 0 10.0 Li ₂ O 0 0 0 0 0 0 Na ₂ O 15.0 14.9 0 0 0 4.0 Ag ₂ O 0.5 1.0 1.0 1.0 1.0 1.0 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− × ◎---Water resistance (%) 35.0-0.5---Antibacterial property ◎-○---Resin coloring ×-○---================== ================

[0023] 4-5: Not completely melted at 1300 ° C for 2 hours. 5, 7: Cannot be prepared only with powdered phosphate raw material. 6, 8: devitrification and no vitrification.

As is clear from the examples shown in Table 1,
With respect to the glass having a composition within the range of the present invention, no metal silver deposition was observed, and resin coloring was hardly observed. It was estimated that coloring was slight and there was no problem in practical use. In addition, the water resistance can be adjusted in a wide range from 0.3% to several tens of% by adjusting the composition, and antibacterial properties were observed although some compositions were slightly weak. This difference in antibacterial property is considered to be due to the difference in the elution rate of silver ions from the glass due to the difference in silver ion content and water resistance. In addition, Comparative Example 1 in Table 2
No. 0 and the above-mentioned JP-A-4-338129, even a phosphoric acid-based glass which has high stability of silver ions and is less likely to be colored when mixed with a resin has a Na ₂ O or K ₂ O content. When the content of the alkali metal oxide is more than 5 mol%, the stability of silver ion in the glass is lowered, and coloring tends to occur when mixed with the resin. However, as shown in Example 4, even if the same alkali metal oxide is Li ₂ O, even if it is contained in the glass,
No coloring occurred when mixed with the resin.

On the other hand, among the comparative examples shown in Table 2, for the borosilicate type compositions 1 and 2, when the silver content is small, metallic silver does not precipitate and the antibacterial property is strong, but when mixed with the resin, it is remarkable. When the silver content was increased, metallic silver was precipitated. Further, JP-A-4-338 of 3 to 5
In the composition included in the scope of claims of 129, for 3 there was no precipitation of metallic silver and a slight coloring of the resin, but the antibacterial property was slightly weak because of good water resistance and a low silver ion elution rate, Regarding the compositions of Nos. 4 and 5, the solubility of the batch was poor and it did not completely melt at 1300 ° C. Also, 5
With respect to the batch of composition, it was impossible to prepare only the powdery phosphate raw material, and it was necessary to use liquid phosphoric acid or phosphoric anhydride having a very strong hygroscopic property. Further, regarding the compositions of 6 to 8 that deviate from the claims of the present invention, glass cannot be obtained by devitrification, or it is impossible to prepare only with a powdery phosphoric acid raw material. Regarding composition No. 10, the antibacterial property was weak, or when it was mixed with resin, remarkable coloring occurred.

[0026]

As described above, according to the present invention, it is possible to obtain an antibacterial glass composition which can contain a large amount of silver ions and is relatively easy to manufacture. Further, the antibacterial glass composition according to the present invention can adjust the elution of silver ions in a relatively wide range in which the antibacterial property is expressed by adjusting the solubility in water, and the antibacterial glass composition according to the application can be used. It is an antibacterial glass composition which can be adjusted in a relatively wide range of properties, and hardly causes coloring even when mixed with a resin.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C03C 3/17

Claims (1)

[Claims] 1. A displayed in _{mol%, P 2 0 5 40~55%} CaO + Mg0 30~60% SiO 2 + Al 2 O 3 0~ 4% Li 2 O + B 2 O 3 0~15% Na 2 O + K 2 O 0~ 5% ZnO + BaO 0~30% provided that (CaO + Mg0 + ZnO + BaO ) total _{30~60% PbO 0~ 5% Ag 2} O antibacterial glass composition characterized in that it consists of from 0.03 to 5% of.