FAST AND ECONOMICAL GLASS FUNCTIONALIZATION IN ONE STEP

Abstract

The present invention provides a method of one step ion exchange for functionalization thin glasses by strengthening and controlling the optical properties. Owing to controllable optical transmittance and absorbance properties, these thin glasses can be utilized as solar control glasses. A paste containing potassium compound and silver compound was applied to the glass substrate containing an alkali metal component by screen printing, thereafter ion exchange heat treatment was performed below glass transition temperature. The method of the invention can produce a glass with surface compressive stress between 550 and 600 MPa, compressive stress layer in the range of 10-15 μm. In the antimicrobial activity test, the amount of alive E. coli bacteria decreased ≥99.9% after 24 hours of contact time. Thin glasses, in which the optical transmittance values are controlled depending on the ion exchange process conditions, spectrally selective, chemically strengthened and showing antimicrobial surface properties that are in accordance with the requirements of the application area, were produced by one step ion exchange.

Claims

1. A method for the strengthening of thin glass with ion exchange in one step and providing antimicrobial properties, comprises the steps of; Cleaning glass substrates with alcohol and distilled water Preparation of ion exchange salt paste by mixing potassium salts and silver salts with distilled water Coating the glass surface by applying the prepared salt paste to the glass surface with screen printing Drying of the coating layer formed by screen printing Application of heat treatment for diffusion and exchange of Ag.sup.+ and K.sup.+ ions in the salt paste mixture and Na.sup.+ ions in the glass Cleaning the ion exchanged glass with alcohol and distilled water.

2. The method according to claim 1, characterized in that the potassium salt is potassium nitrate (KNO.sub.3).

3. The method according to claim 1, characterized in that the potassium salt is preferably contains at least one of potassium nitrate (KNO.sub.3), potassium chloride (KCl), potassium sulphate (K.sub.2SO.sub.4), potassium carbonate (K.sub.2CO.sub.3), potassium bromide (KBr) and potassium iodide (KI) compounds.

4. The method according to claim 1, characterized in that the silver salt is silver nitrate (AgNO.sub.3).

5. The method according to claim 1, characterized in that the silver salt preferably contains at least one of silver chloride (AgCl), silver sulphate (Ag.sub.2SO.sub.4) and silver carbonate (Ag.sub.2CO.sub.3) compounds.

6. The method according to claim 1, characterized in that the ion exchange salt paste contains 95-99.75% by weight of KNO.sub.3 (potassium nitrate).

7. The method according to claim 1, characterized in that the ion exchange salt paste contains ≤5% by weight AgNO.sub.3 (silver nitrate.

8. The method according to claim 1, characterized in that the solid salt concentration in the paste is between 45% and 65% by weight.

9. The method according to claim 1, characterized in that at least one rheological agent (binder) such as kaolin, ochre or other clays, barium carbonate or aluminium oxide is preferably added to the paste mixture.

10. The method according to claim 1, characterized in that the thickness of the paste coating layer is preferably between 0.1 mm and 1 mm.

11. The method according to claim 1, characterized in that the drying process of the paste layer is at least 3 hours, more preferably 6 hours, most preferably 24 hours.

12. The method according to claim 1, characterized in that the ion exchange heat treatment is carried out at a temperature of 350-450° C.

13. The method according to claim 1, characterized in that the ion exchange time is between 20 minutes and 480 minutes.

14. The method according to claim 1, characterized in that it is heat treated at a temperature below the glass transition temperature (T.sub.g).

15. The method according to claim 1, characterized in that the heat treatment can preferably be carried out in a reducing atmosphere.

16. The method according to claim 1, characterized in that the glass is soda lime silicate.

17. The method according to claim 1, characterized in that the glass is preferably soda lime silicate, borosilicate, alkali alumina silicate, alumina borosilicate, lead, alkali barium, phosphate, fluorophosphate.

18. The method according to claim 1, characterized in that the glass thickness is preferably 3 mm or less, more preferably 2 mm or less.

19. The method according to claim 1, characterized in that the alcohol used for cleaning the glass is ethanol or isopropyl.

20. The method according to claim 1, characterized in that the glass contains one or more alkali metal components such as Na, Li in ionic form or as oxide.

Description

DESCRIPTION OF THE FIGURES

[0018] FIG. 1—Process flowchart of manufacturing glass with strengthened, antimicrobial and controllable optical properties according to the present invention

[0019] FIG. 2—Transmittance spectra of untreated and ion exchanged glasses for varying AgNO.sub.3—KNO.sub.3 salt mixtures at a) 360° C. 60 minutes, b) 420° C. 20 minutes, c) 435° C. 480 minutes

[0020] FIG. 3—Absorbance spectra of untreated and ion exchanged glasses for varying AgNO.sub.3—KNO.sub.3 salt mixtures at a) 360° C. 60 minutes, b) 420° C. 20 minutes, c) 435° C. 480 minutes

[0021] FIG. 4—Energy Dispersive Spectrometer (EDS) line scan analysis results for the glass sample ion exchanged at 435° C. for 480 min. with salt paste containing wt. % 5AgNO.sub.3-95KNO.sub.3

[0022] 1: Cleaning glass substrates with ethanol and distilled water [0023] 2: Preparation of paste by mixing KNO.sub.3 and AgNO.sub.3 salts with distilled water [0024] 3: Applying the paste with screen printing on the glass substrate [0025] 4: Drying of the coating layer formed by screen printing [0026] 5: Heat treatment for diffusion and exchange of Ag.sup.+ and K.sup.+ ions in the salt paste mixture and Na.sup.+ ions in the glass [0027] 6: Cleaning of ion exchanged glasses with ethanol and distilled water

DESCRIPTION OF THE INVENTION

[0028] The object of the invention is to provide a one-step ion exchange process to prepare multi-functional thin glass substrates by fast, easy and cost-effective manner. The method provides consistent conditions (in terms of salt composition) during the ion exchange due to use of a continuous (in each application) fresh salt source.

[0029] FIG. 1 is a flow chart of manufacturing strengthened glass with antimicrobial capability and controllable optical properties in one step ion exchange process. As shown in FIG. 1, the method of manufacturing the glass includes following steps:

[0030] Step 1: Cleaning the glass substrate

[0031] Step 2: Preparing a paste by mixing salts KNO.sub.3 and AgNO.sub.3 salts with distilled water

[0032] Step 3: Screen printing the paste upon the glass substrate surface

[0033] Step 4: Drying the screen printed coating film

[0034] Step 5: performing heat treatment for diffusion and exchange of Ag.sup.+ and K.sup.+ ions in the salt paste mixture with Na.sup.+ ions in the glass

[0035] Step 6: Cleaning the ion exchanged glass substrates with ethanol and distilled water

[0036] Invading salt media is comprised at least one potassium salt such as but not limited to potassium nitrate (KNO.sub.3), potassium chloride (KCl), potassium sulphate (K.sub.2SO.sub.4), potassium carbonate (K.sub.2CO.sub.3), potassium bromide (KBr), potassium iodide (KI), potassium bicarbonate (KHCO.sub.3), potassium hydroxide (KOH) and potassium fluoride (KF). Furthermore, invading salt media is comprised one silver salt such as, but not limited to, silver nitrate (AgNO.sub.3), silver chloride (AgCl), silver sulphate (Ag.sub.2SO.sub.4) and silver carbonate (Ag.sub.2CO.sub.3). Besides, zinc and copper salts can be incorporated to the salt media instead of silver or with silver.

[0037] In the method of the invention, the choice of the glass used is not limited to a particular composition. The one and basic necessity is the glass substrate should contain one or more alkali metal component like Na, Li, etc. in an ionic state or as an oxide. The type of glasses can be soda lime silicate, borosilicate, alkali aluminosilicate, aluminoborosilicate, lead, alkali barium, phosphate, fluorophosphate, etc.

[0038] Soda lime silicate glass substrates, 60 mm×60 mm dimensions and ≤1 mm thickness were cut from a mother sheet formed by a float glass process. The thickness of the glass is not especially limited, but it is preferably 3 mm or less, more preferably 2 mm or less, in order to effectively perform the chemical strengthening treatment. The dimensions of the glass can be enlarged depending on the screen frame. It is critical to clean the glass surface, as contamination on the glass surface slows ion exchange and/or causes inhomogeneous ion exchange, causing compression stress and layer depth variation. Therefore; pristine glass substrates were cleaned in ethanol and distilled water for 5 minutes, respectively, in ultrasonic mixer (step 1) and were left to dry naturally in an upright position after cleaning. During cleaning process ethanol or isopropyl alcohol may be used.

[0039] It is important to mix ingredients of the paste to obtain an optimum degree ion exchange process. Inorganic salts as dry ion exchange materials should be mixed with liquid or a liquid-based substance capable of dissolving, dispersing or suspending the salts. It can be water or alcohol-based. In the present work, dry ion exchange materials ≤5 wt. % AgNO.sub.3 and 95-99.75 wt. % KNO.sub.3 were mixed with distilled water for getting a proper paste for coating. AgNO.sub.3 and KNO.sub.3 were mixed in agate mortar for 5 minutes before adding the distilled water and after adding the distilled water, whole paste was mixed in agate mortar for another 5 minutes (step 2). Besides agate mortar, planetary ball mill, vibratory ball mill, stirred ball mill, roll ball mill can be used alternatively for mixing. The paste should have a proper viscosity to apply. If necessary, at least one rheological agent (binder) like kaolin or ochre or any other clays, barium carbonate or aluminium oxide can be added to adjust the viscosity of the paste to suit the application method and it ensures the paste adheres to the glass surface.

[0040] A silk mesh screen (305 mesh, 50 μm mesh opening, 34 μm thread diameter) was placed above the surface of the glass. The atmosphere surface of glass was coated with wet paste composed of distilled water, AgNO.sub.3 and KNO.sub.3 salts (step 3). The concentration of solid salt in the paste was about 45 to 65% by weight and AgNO.sub.3 concentration in the paste was 55 wt. %. Water has the advantage that water vapor released during drying does not affect the environment. The thickness of the paste is not restricted and varies according to the type, amount, etc. of potassium and/or silver compound contained in the paste. In the present work the thickness of the paste was about 0.1 mm to about 1 mm. The desired layer thickness can be achieved by multiple coating step, each followed by drying. The uniform distribution of the paste on the surface of the thin glass substrate should be provided for efficient ion exchange.

[0041] After applying the paste, the resulting coating (paste) film was dried at room temperature prior to heat treatment. Drying process was at least 3 hours, more preferably 6 hours, most preferably 24 hours (step 4). The drying conditions are not limited as long as the coating film is dried, solvent component is sufficiently removed and the paste is dried to a solid.

[0042] Thereafter, the dried coating film is heat treated at a temperature below the transition temperature (T.sub.g) of the glass substrate. Heat treatment temperature is a critical parameter to define ion exchange process and it is dependent on the glass substrate. If the temperature is higher than T.sub.g, the ion exchange will be realized more rapid. However, one should avoid to select a temperature high enough to cause a stress relief in the glass. On the other hand, if the ion exchange temperature is too lower than T.sub.g, the longer time will be necessary to strengthen the surface. For this reason, to determine the optimum ion exchange temperature, DTA measurement was performed by Seiko Exstar 6300 Model DTA/TG instrument (Tokyo, Japan), and T.sub.g of the glass was determined as 560° C. All heat treatments used in this work are lower than T.sub.g of the glass. The ion exchange heat treatments were performed for time between 20 to 480 minutes and at temperature between 350 to 450° C. (step 5). The heat treatment atmosphere was oxygen atmosphere. It is also possible to perform heat treatment in reducing atmosphere. Strengthened and antimicrobial thin glasses with the same transmittance values can be obtained via heat treatment in reducing atmosphere by ion exchange at lower temperatures and shorter times. During the heat treatment, KNO.sub.3 and AgNO.sub.3 salt mixture fully or partially melt into liquid or quasi-liquid state. The substrate was naturally cooled to room temperature inside the furnace. Thus, ion exchange of K.sup.+ and Ag.sup.+ into the glass was realized together for strengthening and antimicrobial activity capability.

[0043] During the ion exchange the thin glass substrates are lied flat inside the furnace. It can be considered to stand vertically or hang in the air. The heat treatment was realized in an electrical box furnace. For industrial production it is possible to use batch-type or continuous furnaces depending on the production volume.

[0044] After then the heat treatment step is completed, it was cleaned with ethanol and distilled water to remove the paste residues remaining on the glass surface (step 6). Following the cleaning step, the glass substrates were left to dry in an upright position. The washing media should be selected to avoid any reactions with material from the paste and/or the glass composition of the glass article.

[0045] Some exemplary process conditions and codes of the glasses are listed in Table 1. R sample was defined as the untreated reference sample that it was not subjected to any surface treatment. K sample was ion exchanged at 435° C. for 480 minutes after applying 100 wt. % KNO.sub.3 salt paste by screen printing. S1-S9 samples were prepared by screen printing salt paste including increasing amount of AgNO.sub.3 mixed with KNO.sub.3.

TABLE-US-00001 TABLE 1 Exemplary sample codes and process conditions Sample Salt mixture Ion exchange temperature code (weight %) and time (° C. and minutes) R — — K 100 KNO.sub.3  435, 480 S1 99.75 KNO.sub.3, 0.25 AgNO.sub.3 360, 60 S2 99 KNO.sub.3, 1 AgNO.sub.3 360, 60 S3 95 KNO.sub.3, 5 AgNO.sub.3 360, 60 S4 99.75 KNO.sub.3, 0.25 AgNO.sub.3 420, 20 S5 99 KNO.sub.3, 1 AgNO.sub.3 420, 20 S6 95 KNO.sub.3, 5 AgNO.sub.3 420, 20 S7 99.75 KNO.sub.3, 0.25 AgNO.sub.3  435, 480 S8 99 KNO.sub.3,1 AgNO.sub.3  435, 480 S9 95 KNO.sub.3, 5 AgNO.sub.3  435, 480

[0046] Compressive stress and depth of stress layer of the ion exchanged glasses described herein were measured by FSM-6000LE manufactured by Orihara Co., Ltd. (Tokyo, Japan). Measurements were taken from five different samples from each set and from 5 different points of each of these glasses' atmosphere surfaces. FSM measurements of exemplary samples were given in Table 2. In the ion exchanged glasses according to the present invention, the depth of compressive stress layer is 5 μm or more, preferably 10 μm or more, and more preferably 15 μm or more, less than 20 μm. The surface compressive stress value of the ion exchanged glasses according to present invention is preferably 300 MPa or more, more preferably 400 MPa or more, and most preferably 500 MPa or more. In the same ion exchange process conditions (435° C. for 480 minutes), surface compressive stress of S7, S8, and S9 glasses were very close to K glass which ion exchanged with 100 wt. % KNO.sub.3 salt.

TABLE-US-00002 TABLE 2 Exemplary surface compressive stress and depth of stress layer measurements for glasses Ion exchange Surface Depth of temperature compressive stress Sample Salt mixture and time (° C. stress layer code (Weight %) and minutes) (MPa) (μm) K 100 KNO.sub.3 435, 480 595 11 S7 99.75 KNO.sub.3, 435, 480 590 14 0.25 AgNO.sub.3 S8 99 KNO.sub.3, 435, 480 589 11 1 AgNO.sub.3 S9 95 KNO.sub.3, 435, 480 586 12 5 AgNO.sub.3

[0047] Silver and potassium incorporation to the glass was studied using Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS) technique. Analysis results in Table 3, shows the concentration of the elements on the glass surface. Silver concentration on the glass surface exhibited an increase with increasing AgNO.sub.3 concentration in the salt paste, ion exchange temperature and ion exchange time. The amount of incorporated potassium ions to the glass surface decreased with increasing AgNO.sub.3 concentration in the salt paste mixture. Thus, in the case of the increase in the amount of incorporated silver ions while a decrease in potassium ions, compressive stress on the surface slightly decreased.

[0048] Penetration depths of incorporated ions were examined by EDS line scan analysis. The exemplary line scan analysis results graph for the glass ion exchanged at 435° C. for 480 min. with salt paste containing wt. % 5AgNO.sub.3-95KNO.sub.3 is shown in FIG. 4. Potassium/sodium and silver/sodium exchanges took place simultaneously during the ion exchange due to the use of AgNO.sub.3—KNO.sub.3 mixed salt paste. The ionic radius of silver (129 μm) is much smaller than that of potassium (152 μm), so incorporation of silver ions is more effective and silver ions diffuse into the glass faster than the potassium ions. Therefore, the penetration depth of silver ions is higher than potassium ions (penetration depths of silver and potassium ions are 24 μm and 12 μm, respectively).

TABLE-US-00003 TABLE 3 Exemplary silver and potassium concentrations of ion exchanged glasses Ion exchange EDS results temperature (Weight %) Sample Salt mixture and time (° C. Surface concentration code (Weight %) and minutes) Ag K K 100 KNO.sub.3  435, 480 — 12.20 S1 99.75 KNO.sub.3, 360, 60 2.04 13.07 0.25 AgNO.sub.3 S2 99 KNO.sub.3, 360, 60 3.49 11.29 1 AgNO.sub.3 S3 95 KNO.sub.3, 360, 60 6.08 11.24 5 AgNO.sub.3 S4 99.75 KNO.sub.3, 420, 20 4.28 13.22 0.25 AgNO.sub.3 S5 99 KNO.sub.3, 420, 20 5.60 12.52 1 AgNO.sub.3 S6 95 KNO.sub.3, 420, 20 6.52 12.56 5 AgNO.sub.3 S7 99.75 KNO.sub.3,  435, 480 5.37 11.99 0.25 AgNO.sub.3 S8 99 KNO.sub.3,  435, 480 16.68 10.64 1 AgNO.sub.3 S9 95 KNO.sub.3,  435, 480 26.77 10.35 5 AgNO.sub.3

[0049] The antimicrobial activity and efficacy of the ion exchanged glasses were determined in accordance with Japanese Industrial Standard JIS Z 2801 (2000), entitled “Antimicrobial Products Test for Antimicrobial Activity and Efficacy.” The antimicrobial activities of the ion exchanged samples were determined against Escherichia coli (E. coli). E. coli bacteria which represents the gram (−) microorganisms was preferred in the tests because it is frequently encountered. The antimicrobial activity is defined in JIS Z2801 standard as a value which shows the difference in logarithmic values of number of viable bacteria between the antimicrobial product and the untreated product after inoculation followed by incubation of bacteria. According to the testing method of JIS Z2801 standard, if the logarithmic reduction in number of bacteria from initial load (immediately after inoculation) and bacteria load at the end of 24 hours is 2 or higher, the test samples are inhibited the microbial growth, was judged to give antimicrobial activity and determined as they have the antimicrobial effectiveness. Glass samples which are not subjected to ion exchange treatment were used as control sample. As it is seen in Table 4, control sample which was untreated did not exhibit inhibition on the viable colonies (no log and percent reduction). According to exemplary embodiments, the multi-functional thin glasses are capable of inhibiting an antimicrobial efficacy greater than 99.9%.

TABLE-US-00004 TABLE 4 Antimicrobial efficacies of the glasses against E. coli E. coli Microbial load - Number of surviving bacteria (cfu*/ml) At 35° C. for Log Percent Sample ID Beginning 24.sup.th hour reduction** reduction R 3.45 × 10.sup.5 6.00 × 10.sup.5 −0.3 — (Control sample) S3 3.95 × 10.sup.5 <10 >4.07 >99.99 S6 4.40 × 10.sup.5 <10 >4.12 >99.99 S9 4.87 × 10.sup.5 <10 >3.6 >99.9 *cfu: Colony forming unit **Log reduction: [Log Initial load (cfu/ml) − Log 24 hour load (cfu/ml)] − Log change bacteria control

[0050] The use of Ag ions in ion exchange process can cause a yellowing due to formation and growth of metallic silver nanoparticles or clusters. When nanoscale silver particles are excited by electromagnetic radiations, they exhibit an optical absorption called Surface Plasmon Resonance (SPR). SPR absorption occurs due to the periodic oscillation of conduction band electrons in metal and takes place at the interface of the metal nanoparticle-dielectric matrix [26-31]. Despite the typical Ag.sup.0 SPR peak is at a wavelength around 200 nm (UV region), when Ag atoms become larger and nanoparticles occur, their SPR peak shift to higher wavelengths (the visible range) [28, 32]. The silver nanoparticles/nanoclusters which absorb light at the SPR peak wavelength causes yellow colouring. In some applications of antimicrobial and strengthened glass a certain level optical transmittance is necessary. Therefore, while the strength of the glass is increased with the ion exchange process, it is also important that the optical transmittance is not reduced to a level that will affect the visual quality. For this reason, transmittance and absorbance measurement of ion exchanged glass were performed at room temperature by Lambda 750S UV-Vis-NIR spectrophotometer manufactured by Perkin Elmer (Massachusetts, USA). The measurements were carried out from the atmosphere surfaces of the ion exchanged glasses at a scanning speed of 5 nm/s and in the wavelength range of 250-2500 nm. In order to make comparison, the same measurements were realized in glass that did not ion exchange (R glass) and glass ion exchanged for 480 hours at 435° C. with 100 wt. % KNO.sub.3 salt paste (K glass). The average transmittance and absorbance values were determined for each group by taking 6 measuring from atmosphere surfaces of the glass substrates. FIGS. 2 and 3 shows the transmission and absorption spectra of glasses. Light, solar direct, IR and UV transmittance values of ion exchanged glasses were calculated by using the data from transmittance measurements and were given in Table 5. Table 5 shows that transmittance values were decreased according to the increasing silver concentration in the paste, increasing ion exchange temperature and time. Decrease in the visible region transmission is attributed to the colouring effect of silver. Ion exchanging the glass substrates with process conditions defined in this invention, it is possible to produce solar control glasses with light transmittance in the range of 20-76% and with solar direct transmittance in the range of 24-68% which allow a comfortable working and living environment by limiting the solar heat entrance into the building and controlling the excessive cooling energy consumption and consequently cooling costs in air-conditioned environments.

[0051] Absorbance measurements were conducted between 250-2500 nm, but to see the SPR peaks more clearly, the absorbance spectra was plotted between 300-800 nm. As is apparent from FIG. 3, the higher the silver nitrate concentration in the paste and higher ion exchange temperature, the more significant absorption bands can be seen.

TABLE-US-00005 TABLE 5 Exemplary transmittance values of glasses Salt Ion exchange mixture temperature Transmittance (%) Sample (Weight and time (° C. Day Solar code %) and minutes) light direct IR UV R — — 91.6 90.0 89.6 79.9 K 100 435, 480 91.4 89.6 89.0 79.3 KNO.sub.3 S1 99.75 360, 60 85.0 83.8 88.0 49.9 KNO.sub.3, 0.25 AgNO.sub.3 S2 99 360 , 60 77.1 77.7 87.2 31.0 KNO.sub.3, 1 AgNO.sub.3 S3 95 360, 60 69.4 72.3 86.4 16.0 KNO.sub.3, 5 AgNO.sub.3 S4 99.75 420, 20 77.1 78.2 87.4 36.1 KNO.sub.3, 0.25 AgNO.sub.3 S5 99 420, 20 56.7 66.0 85.4 13.0 KNO.sub.3, 1 AgNO.sub.3 S6 95 420, 20 60.0 67.2 85.5 11.0 KNO.sub.3, 5 AgNO.sub.3 S7 99.75 435, 480 74.0 76.0 87.0 41.0 KNO.sub.3, 0.25 AgNO.sub.3 S8 99 435, 480 26.7 51.0 81.7 1.3 KNO.sub.3, 1 AgNO.sub.3 S9 95 435, 480 26.3 50.9 81.7 0.5 KNO.sub.3, 5 AgNO.sub.3

[0052] Silver absorbance (SPR-surface plasmon resonance) peaks are seen in the absorbance graphs of the glasses that have been ion exchanged for 480 minutes at 435° C. SPR absorption peaks are characteristic peaks seen at a wavelength according to the shape, structure and size of the nanoparticles and the structure of the glassy medium. Average particle radius (R) of the embedded nanoparticles are calculated by multiplying a Fermi velocity specifically defined for each element (Vf=1.39×108 cm/s for silver) and the square of the experimentally measured surface plasmon vibration value (wavelength) of this material, dividing this value by the product of speed of light and the full-width half maximum of the optical absorption peak which is given in Equation land results are shown in Table 6.

[00001]$\begin{array}{cc}R=\frac{V_f*{\lambda }_p^2}{2\pi *C^{*}\Delta \lambda }& \mathrm{Equation}1\end{array}$

[0053] R=Average particle radius (nm)

[0054] Vf=Fermi Velocity of Electrons (Silver: 1.39×10.sup.8 cm/s)

[0055] λp=SPR maximum peak intensity

[0056] C=Speed of light

[0057] Δλ=FWHM (full-width half-maximum intensity of the optical absorption peak)

[0058] SPR peak was obtained in each of the glasses that applied ion exchange at 435° C. for 480 minutes with salt pastes prepared by adding 0.25-1-5 wt. % AgNO.sub.3 to the KNO.sub.3 salt. It is known that the reduction of Ag.sup.+ ions to metallic silver occurs at about 450° C. However, the fact that SPR peaks of metallic silver started to form at 435° C. indicates that Ag.sup.+ ions began to be reduced at this temperature and Si—O and Ag—Ag bonds began to form. SPR peak was not obtained at lower ion exchange temperature and shorter ion exchange time. This is due to the fact that most of the silver that enters the glass structure is in ionic form. In addition, it was determined that the silver nanoparticle radii calculated from the absorbance peaks with the increasing AgNO.sub.3 amount in the salt paste mixture increased due to the shift of the SPR absorbance peaks in the absorbance graphs to higher wavelengths.

TABLE-US-00006 TABLE 6 Exemplary average particle radius of silver nanoclusters calculated from absorbance measurements on atmospheric surfaces of glasses Ion exchange Absorbance Average temperature peak particle Sample Salt mixture and time (° C. wavelength radius code (Weight %) and minutes) (nm) (nm) S7 99.75 KNO.sub.3 - 435, 480 440 1.443 0.25 AgNO.sub.3 S8 99 KNO.sub.3 - 435, 480 448 1.481 1 AgNO.sub.3 S9 95 KNO.sub.3 - 435, 480 442 1.602 5 AgNO.sub.3

INDUSTRIAL APPLICATION OF THE INVENTION

[0059] In order for any industrial enterprise to produce alkali-containing thin glasses with a size of 1500×3000 mm and a thickness range of 0.5-2 mm, which have been strengthened and have antimicrobial properties, the company must purchase a fully automatic ultrasonic cleaning system, coating system and heat treatment furnace (approximate cost 270.000 Euro+VAT).

[0060] These glasses; on the screens of electronic devices such as mobile phones, cash machines, video game systems, electronic book readers, tablets, computers, navigation devices, on the glass parts of laboratory equipment that are required to remain sterile, in public subway-toilets, etc. It can be used in places where bacteria formation is not desired, on vehicle windows, white goods exteriors, various glassware and decoration products, pharmaceutical packaging, ultra-sensitive chemical and biological detection systems, and the production of optical waveguides.

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