JPH07291654A - Antimicrobial glass powder - Google Patents

Abstract

PURPOSE:To produce borosilicate-based antimicrobial glass powder, containing silver therein and hardly discoloring in addition thereof in a powdery form into an organic material such as a coating resin film or a resin molding or an inorganic material. CONSTITUTION:This aintimicrobial glass powder has a component comprising 25-60wt.% SiO2, 18-60wt.% B2O3, 0-20wt.% Al2O3, 8-30wt.% R2O (R is Li, Na or K), 0-20wt.% R'O (R' is Ca, Mg, Zn or Ba), 0.05-2.0wt.% Ag2O and 0.1-2.0wt.% total amount of CeO2 and TiO2. The glass powder is used for addition into an organic or an inorganic material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial glass powder, and more particularly to a glass powder capable of imparting an antibacterial effect when added to various organic or inorganic materials.

[0002]

2. Description of the Related Art Conventionally, metal, glass, plastic,
An attempt was made to form an organic or inorganic coating film containing an inorganic substance having antibacterial properties on the surface of wood, etc., and to exert an antibacterial effect on the coating film. Attempts to include and exert an antibacterial effect, and wall materials made of gypsum, mortar, calcium silicate, etc.
There has been proposed an attempt to add antibacterial and antifungal properties by mixing and adding powder of an inorganic substance having antibacterial properties to the interior of building materials such as ceiling materials and interior materials and various joints.

Typical examples of such inorganic substances having an antibacterial action include zeolite carrying silver ions and elutable glass containing silver ions. However, silver ions contained in zeolite or glass are easily reduced by sunlight or heat to become metallic silver when coexisting with resin, resulting in discoloration of the coating film or resin (mainly brown). It was often done. Therefore, as a glass that suppresses such discoloration due to the reduction of silver ions, a phosphate glass having a low alkali content has been disclosed (JP-A-4-338129). However, the raw material cost of phosphate glass is generally higher than that of borosilicate glass, and when the same concentration of silver ions is contained, the antibacterial activity of phosphate glass is weaker than that of borosilicate glass. . Therefore, it is considered that the borosilicate type is more suitable than the phosphate type as the composition of the silver-containing glass, but an effective composition for suppressing discoloration due to silver has been developed in the borosilicate type glass composition. There was no example.

[0004]

In view of the above-mentioned circumstances, the present invention provides a silver-containing borosilicate antibacterial glass powder which is resistant to discoloration when added to various organic or inorganic materials in powder form. It is intended to be provided.

[0005]

The present inventors have added cerium oxide or titanium oxide to the glass composition so that silver in glass can be easily converted into metallic silver by heat or light even when coexisting with a resin or the like. The present invention has been achieved by finding that they exist stably in an ionic state without being reduced.

That is, the present invention, expressed in% by weight,
SiO2 25-60, B2 O3 18-60, Al
2O3 0-20, R2O 8-30, (R = L
i, Na, K) R'O 0-20, (R '= Ca, Mg, Zn,
Ba) Ag2O 0.05 to 2.0, CeO2 + TiO2
An antibacterial glass powder having a composition of 0.1 to 2.0 to be added to a coating resin film and a resin molded product.

In the present invention, the details of the effect of cerium oxide on such silver ions are not clear, but it can be qualitatively explained as follows. Ag ⁺ ions are reduced to metallic Ag by sunlight irradiation (mainly near ultraviolet rays). C
Since all the e ³⁺ , Ce ⁴⁺ , and Ti ⁴⁺ ions absorb ultraviolet light to near-ultraviolet light, Ce ³⁺ , Ce in the vicinity of Ag ⁺ ions are
The presence of ⁴⁺ and Ti ⁴⁺ ions suppresses the reduction of Ag ⁺ ions. As described above, the presence of cerium oxide or titanium oxide is considered to have an effect of suppressing the reduction of Ag ⁺ ions due to the irradiation of sunlight. In addition, Ce ³⁺ and Ag ⁺
It is known that the reaction of Ce ³⁺ + Ag ⁺ → Ce ⁴⁺ + Ag when coexisting occurs with ultraviolet irradiation for a long time. However, since this reaction occurs only at a high temperature of 200 ° C. or higher, there is no influence of the reduction of Ag ⁺ ions by this reaction under the normal use conditions.

Further, in particular, cerium oxide (CeO2)
It acts as an oxidant during the melting of the glass and promotes the ionization of silver, so that it is presumed that the function of stably holding Ag ⁺ ions in the glass in the ionic state is particularly strong.

Therefore, it is considered that Ag ⁺ ions in the coexistence of cerium oxide or titanium oxide act synergistically with the above-mentioned effects, and as a result, are in a state in which they are not easily reduced easily. It is thought to be the cause of suppressing discoloration when combined with.

Next, the composition of the glass powder containing antibacterial silver used in the present invention will be described in detail. The composition is expressed in% by weight, SiO2 25-60, B2 O3 18-6.
0, Al2O3 0-20, R2O 8-30,
(R = Li, Na, K) R'O 0-20, (R '= Ca, Mg, Zn,
Ba) Ag2O 0.05 to 2.0, CeO2 + TiO2
It is 0.1 to 2.0. The reason for limiting the composition in this way is as follows.

In the present invention, the SiO2 component has a skeleton of glass, and its content is 25 to 60% by weight,
It is preferably 30 to 55% by weight. Below 25% by weight is A
Since the amount of g ⁺ ions and glass components eluted is too large, the life (or durability) of the antibacterial glass powder is extremely shortened. On the other hand, if it exceeds 60% by weight, the viscosity is increased and it becomes difficult to melt the glass, and the elution amount of Ag ⁺ ions is too small and the antibacterial performance is not sufficient. B2 O3 promotes the elution of Ag ions from the glass and contributes to the stabilization of Ag + ions, and is 18 to 60% by weight, preferably 20 to 55% by weight. If it is less than 18% by weight, the elution amount of Ag + ions is too small and the antibacterial performance is weak, and metallic silver is likely to precipitate during glass melting. If it exceeds 60% by weight, the glass elution amount becomes too large and the life becomes extremely short, and if it is contained more than this amount, it is not so effective in stabilizing Ag + ions.

Al 2 O 3 is not an essential component, but it suppresses the glass from being eluted too much and contributes to the stabilization of Ag ⁺ ions, and is 0 to 20% by weight, preferably 1 to 10% by weight.
If it exceeds 20% by weight, the amount of glass eluted is too small, the antibacterial performance is weakened, the viscosity is increased, and the glass is difficult to melt.

R2O (where R represents Li, Na and K) promotes melting and elution of glass.
The total content of O, Na2O and K2O is 8 to 30% by weight, preferably 10 to 20% by weight. If it is less than 8% by weight, the effect of promoting elution is small, and if it exceeds 30% by weight, the amount of glass eluted is too large and the durability is poor.

R'O (where R'is Ca, Mg, Zn,
(Representing Ba) is not an essential component, but promotes melting and elution of glass like R2O.
The total amount of O, ZnO and BaO is 0 to 20% by weight, preferably 0 to 10% by weight. If it exceeds 20% by weight, R2
When used in combination with O, the amount of gas eluted becomes too large and durability becomes poor.

Ag ² O is an essential component for antibacterial property, which becomes Ag ⁺ ion in glass, and is 0.05 to 2.0% by weight, preferably
It is 0.1 to 1.0% by weight. If it is less than 0.05% by weight, the elution of Ag ⁺ ions is suppressed and the antibacterial property is poor, and if it exceeds 2.0% by weight, not only the antibacterial property is small and the precipitation of metallic silver which causes discoloration considerably increases, but also glass manufacturing The cost required for is also high.

CeO2 and TiO2 are essential components for suppressing the reduction of Ag ⁺ ions, and their total amount is 0.1 to 0.1%.
It is 2.0% by weight, preferably 0.25 to 1.0% by weight. If it is less than 0.1%, the stabilization of Ag ⁺ ions is not sufficient, and if it exceeds 2.0%, the yellow coloring of the glass due to Ce ⁴⁺ , Ce ³⁺ , Ti ⁴⁺ becomes remarkable and it is necessary for glass production. The cost will also be high. Further, halogens such as F2, Cl2 and Br2 react with Ag in the glass to form silver halide, which is easily reduced to metallic silver. Therefore, it is preferable that halogens other than impurities are not contained as much as possible.

If the particle size of the antibacterial silver-containing glass powder of the present invention is too large, the surface area becomes relatively small and the antibacterial property becomes small. Conversely, if the particle size is too small, the antibacterial property is limited. It is preferable that the average particle diameter of the glass powder is within the range of 2 to 200 μm because the above does not increase and the crushing work takes time.

The antibacterial silver-containing glass powder is usually
It is added so as to be contained in an amount of 1 to 50% by weight in a coating resin film, a resin molded product, or other organic material or inorganic material.

[0019]

EXAMPLES Examples of discoloration test and antibacterial test of the glass powder according to the present invention will be described below. Example 1 A raw material prepared by adding 1.0 parts by weight of Ag2O and 0.5 parts by weight of CeO2 to 100 parts by weight of a mixture consisting of 35% by weight of SiO2, 15% by weight of Na2O, and 50% by weight of B2O3 was used in an electric furnace.
After melting at 0 ~ 1300 ℃ for 2 hours, quenching and vitrifying,
A sample of Example 1 was pulverized with a ball mill to a particle size of 38 to 105 μm. The following discoloration and antibacterial tests were conducted on this glass powder.

(Discoloration test) 1. Photodiscoloration test A glass powder sample was mixed with a commercially available crosslinking reaction type organopolysiloxane-based coating agent (Atom Cerasion # 300 manufactured by Atom Chemical Co., Ltd .; solid content: 29% by weight) at a ratio of 1: 0.1. The antibacterial coating agent was prepared by mixing in a weight ratio of. This coating agent is sprayed onto the surface of an air filter (5 cm x 5 cm) using a glass fiber non-woven fabric with a thickness of about 0.5 mm made by wet-fabrication of glass fibers with a diameter of about 0.8 μm, and the total film thickness is about A coating film having a thickness of 15 μm was prepared and used as a test piece. This test piece was irradiated with light using a sunshine weather meter for 350 hours, and then the change in color tone of the coating film was observed. The results are shown in the table. As shown in the table, it was found that this test piece had no discoloration due to sunlight irradiation.

2. Thermal Discoloration Test 2 g of polyethylene resin powder and 2 g of glass powder sample were added to a glass beaker, mixed well and heated to 200 ° C. to observe discoloration of the resin. The results are shown in the table. As shown in the table, this test piece was found to have little discoloration due to mixing with resin and heating.

(Antibacterial Test) 1. Sample Preparation Alumina powder is mixed at a ratio of 10 parts by weight to 1 part by weight of glass powder sample. This is a cylinder with a diameter of 12.2 mm (thickness approx.
1.5mm) is press-molded at a pressure of about 100kgf / cm to make a test piece for antibacterial test.

2. Strains used Mold (a) Aspergillus niger (b) Cladosporium cladosporioides (c) Penicillium funiculosum bacteria (d) Escherichi coil (E. coli) (e) Staphylococcus aureus (Staphylococcus aureus)

3. Test method Mold The spore suspension prepared from glass was prepared by allowing a test piece for antibacterial test to stand on a glucose-peptone-agar medium and adjusting the concentration to 1 × 10 ⁶ cells / ml. About 1 ml was sprayed with a sprayer. This was cultured at 28 ° C for 7 days in a constant temperature bath, and the width of the growth inhibition zone (halo) formed around the test piece was observed. The results are shown in the table. However, the width W (mm) of the halo is determined by the following. W = (T-D) / 2 T: Total diameter of sample and halo (mm) D: Diameter of sample (mm)

Bacteria: The test piece was allowed to stand on a standard agar medium and 1 × 10 5
About 1 ml of the bacterial solution prepared to be ⁶ cells / ml was sprayed with a glass sprayer. This was cultured in a constant temperature bath at 37 ° C. for 2 days, and the width of the growth inhibition zone (halo) formed around the test piece was observed. The results are shown in the table. The results are shown in the table.

[0026]

[Table 1] Table ------------------ Test item Example 1 Example 2 Comparative example 1 Comparative Example 2 Comparative Example 3 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Discoloration test Light irradiation No change No change Remarkably browning No remarkably browning No heating with resin Very slight Very slightly Remarkably yellowing Remarkably yellowing No yellowing No yellowing --------------------- −−−−−−−−−−−−−−−−−−− Antibacterial test (halo width mm) Aspergillus niger 10 or more 10 or more 10 or more 10 or more 2 or less Cladosporium cladosporioides 10 or more 10 or more 10 or more 10 or more 2 or less Penicillium funiculosum 10 or more 10 or more 10 or more 10 or more 10 or more 2 or less Escherichi coil 10 or more 10 or more 10 or more 10 or more 2 or less Staphylococcus aureus 10 or more 10 or more 10 or more 10 or more 2 or less −−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

As shown in the table, it was found that the antibacterial effect was equivalent to that of Comparative Example 1 described later. This indicates that addition of CeO2 does not interfere with the antibacterial effect of Ag ⁺ ions.

Example 2 50% by weight of SiO2, 10% by weight of Na2O, 40% of B2O3
In an electric furnace, a raw material obtained by adding 1.0 part by weight of Ag2O and 1.0 part by weight of CeO2 to 100 parts by weight of a mixture composed of 1% by weight was used.
A sample of Example 1 was obtained by melting at 100 to 1300 ° C. for 2 hours, rapidly cooling to vitrify, and then crushed by a ball mill to have a particle size of 38 to 105 μm. This glass powder was subjected to the same discoloration and antibacterial test as in Example 1. Also in this example, it was found that a glass powder having little discoloration due to sunlight irradiation, mixing with a resin, and heating and having a strong antibacterial activity was produced.

Comparative Example 1 1.0 part by weight of Ag2O based on 100 parts by weight of a mixture consisting of 35% by weight of SiO2, 15% by weight of Na2O and 50% by weight of B2O3,
CeO2 0.03 parts by weight added raw material 1100 ~
Example 1 was prepared by melting at 1300 ° C. for 2 hours, rapidly cooling and vitrifying, and then pulverizing with a ball mill to a particle size of 38 to 105 μm.
Of the sample. This glass powder was subjected to the same discoloration and antibacterial test as in Example 1. Although the sample of this example has the same antibacterial activity as that of Example 1, it was found that discoloration due to sunlight irradiation, mixing with a resin and heating was remarkable.

Comparative Example 2 The raw material obtained by removing the CeO 2 content from the composition of Example 1 was melted in an electric furnace at 1100 to 1300 ° C. for 2 hours, rapidly cooled and vitrified, and then the particle size was adjusted to 38 to 105 μm by a ball mill. The pulverized product was used as the sample of Comparative Example 1. The glass powder was subjected to the same antibacterial and discoloration tests as in Example 1. The results are shown in the table. As a result of the discoloration test, it was found that the glass of the present composition containing no CeO2 had the same antibacterial activity as that of Example 1, but the discoloration due to light irradiation and mixing with the resin was remarkable.

Comparative Example 3 P.O.sub.5 74.85% by weight (50 mol%), MgO 18.70% by weight
(44 mol%), Al2O3 6.45 wt% (6 mol%) 100 parts by weight of a mixture containing 1.0 parts by weight of Ag2O is melted in an electric furnace at 1100 to 1300 ° C for 2 hours and then rapidly cooled to obtain a glass. After crushing, the particle size is 38-105μ with a ball mill.
The sample crushed to m was used as the sample of Comparative Example 2. The glass powder was subjected to the same antibacterial and discoloration tests as in Example 1. The results are shown in the table. As shown in the table, the phosphate glass of this composition was not discolored by light irradiation and addition of resin, but was found to be inferior to the borosilicate glass in antibacterial activity.

Example 3 A mixture of 100 parts by weight of a mixture consisting of 35% by weight of SiO2, 15% by weight of Na20 and 50% by weight of B2O3 was added with 1.0 part by weight of Ag2O and 0.5 parts by weight of TiO2 as a raw material in an electric furnace.
After melting at 0 ~ 1300 ℃ for 2 hours, quenching and vitrifying,
A sample of Example 1 was pulverized with a ball mill to a particle size of 38 to 105 μm. The glass powder was subjected to the same antibacterial and discoloration tests as in Example 1. The results are shown in the table. Also in this example, it was found that a glass powder having little discoloration due to sunlight irradiation, mixing with a resin and heating, and having a strong antibacterial activity was produced.

Example 4 50% by weight of SiO2, 10% by weight of Na20, 40% of B2O3
A raw material prepared by adding 1.0 part by weight of Ag2O and 1.0 part by weight of TiO2 to 100 parts by weight of a mixture consisting of 1% by weight is melted in an electric furnace at 1100-1300 ° C for 2 hours, then rapidly cooled and vitrified, and then ball milled. The sample of Example 1 was ground to a particle size of 38 to 105 μm. The glass powder was subjected to the same antibacterial and discoloration tests as in Example 1. The results are shown in the table. Also in this example, it was found that a glass powder having little discoloration due to sunlight irradiation, mixing with a resin and heating, and having a strong antibacterial activity was produced.

Example 5 35% by weight of SiO2, 15% by weight of Na20, 50% of B2O3
A raw material prepared by adding 1.0 parts by weight of Ag2O, 0.3 parts by weight of CeO2, and 0.3 parts by weight of TiO2 to 100 parts by weight of a mixture consisting of 1% by weight is melted in an electric furnace at 1100-1300 ° C for 2 hours and then rapidly cooled. After vitrification, the particle size is 38 with a ball mill.
The sample of Example 1 was ground to ˜105 μm. The glass powder was subjected to the same antibacterial and discoloration tests as in Example 1. The results are shown in the table. Also in this example, it was found that a glass powder having little discoloration due to sunlight irradiation, mixing with a resin and heating, and having a strong antibacterial activity was produced.

[0035]

[Table 2]

[0036]

As described above, when the antibacterial glass powder of the present invention is added to the coating resin film or the resin molded product in powder form, there is almost no discoloration due to sunlight irradiation and heating, and It has an advantage that it has superior antibacterial activity as compared with the conventionally proposed phosphate glass for adding a color-changing resin.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshikazu Kondo 3-5-11 Doshomachi, Chuo-ku, Osaka City Japan Sheet Glass Co., Ltd.

Claims (1)

[Claims] 1. In weight%, SiO2 25-60, B2O3 18-60, Al2O3 0-20, R2O 8-30, (R = Li, Na, K) R'O 0-20, (R ' = Ca, Mg, Zn, Ba) Ag2O 0.05-2.0, CeO2 + TiO2 0.1-2.0 Antibacterial glass powder to be added into an organic material or an inorganic material having a composition of 0.1-2.0.