KR101325513B1 - Method for antibacterial treatment of glass and the product of the same - Google Patents

Abstract

The present invention relates to an ion exchange method for antimicrobial treatment of glass and to a glass antimicrobial treatment by the method, more specifically, to silver or copper-based material on at least one side of the glass substrate by the solid phase or liquid coating method Or an ion exchange method for antimicrobial treatment of glass for antimicrobial treatment of a glass substrate by applying a coating method of a solution containing silver or copper-based material as a sole component, and a glass antimicrobial treated by the method.
According to the present invention as described above, the possibility of harming the human body by using an ion exchange method or a sol coating method for antimicrobial treatment, especially in the tool related to life while glass is applied, the antimicrobial treatment on glass. Can be excluded. In addition, by further performing an etching process on at least one surface of the glass substrate to remove the flaw present on the surface of the glass as much as possible to improve the light transmission performance, and by performing an ion exchange here to the glass used for display It effectively prevents the growth of bacteria that can occur in contact with the human body, and can also solve the problem of inhibition of light transmittance which is a problem after ion exchange for antibacterial treatment. In addition, in the ion exchange strengthening method of the glass by immersion of molten salt, unlike the immersion order, the immersion depth, the penetration depth of the ions to be exchanged, such as silver or copper, and the amount of penetration, which may cause a difference in performance due to antibacterial treatment, The glass substrates to be treated with antimicrobial treatment can achieve the same antimicrobial performance by maintaining the same process variables and conditions, and can provide reproducibility. Thus, the antimicrobial treatment of glass substrates under such batch process variables and conditions increases yield, and the final glass product is It has the same antimicrobial performance and can increase the reliability of the product. In addition, by coating a solution consisting of a single component of silver or copper-based material, even if the antimicrobial film is thin, the antimicrobial effect is excellent, and the light transmittance can be prevented due to the thin film formation. In addition, since the process for preparing the solution is simple and the raw material is inexpensive, process and cost-effectiveness can be achieved.

Description

Method for antibacterial treatment of glass and the product of the same}

The present invention relates to a method for antibacterial treatment of glass and to glass that has been antibacterial by the method. More specifically, at least one surface of the glass substrate is ion-exchanged by a solid or liquid coating method or silver or copper The antimicrobial treatment method of glass which antibacterially processes a glass base material by apply | coating by the coating method of the solution which uses a system material as a sole component, and the glass antimicrobial treatment by this method are provided.

According to the present invention as described above, the possibility of harming the human body by using an ion exchange method or a sol coating method for antimicrobial treatment, especially in the tool related to life while glass is applied, the antimicrobial treatment on glass. Can be excluded. In addition, by further performing an etching process on at least one surface of the glass substrate to remove the flaw present on the surface of the glass as much as possible to improve the light transmission performance, and by performing an ion exchange here to the glass used for display It effectively prevents the growth of bacteria that can occur in contact with the human body, and can also solve the problem of inhibition of light transmittance which is a problem after ion exchange for antibacterial treatment. In addition, in the ion exchange strengthening method of the glass by immersion of molten salt, unlike the immersion order, the immersion depth, the penetration depth of the ions to be exchanged, such as silver or copper, and the amount of penetration, which may cause a difference in performance due to antibacterial treatment, The glass substrates to be treated with antimicrobial treatment can achieve the same antimicrobial performance by maintaining the same process variables and conditions, and can provide reproducibility. Thus, the antimicrobial treatment of glass substrates under such batch process variables and conditions increases yield, and the final glass product is It has the same antimicrobial performance and can increase the reliability of the product. In addition, by coating a solution consisting of a single component of silver or copper-based material, even if the antimicrobial film is thin, the antimicrobial effect is excellent, and the light transmittance can be prevented due to the thin film formation. In addition, since the process for preparing the solution is simple and the raw material is inexpensive, process and cost-effectiveness can be achieved.

In everyday life, glass is used for a myriad of purposes. In particular, glass is applied to devices and tools related to eating habits such as kitchenware, cold and hot water heaters, and environment-related devices such as humidifiers and cold air blowers. In the process of using these tools and devices continuously, It begins to multiply, and sometimes these bacteria cause serious diseases in the human body.

On the other hand, display devices for directly displaying information such as mobile phones, PDAs, and notebook computers are usually made of glass. On the other hand, as these display devices are miniaturized, they are portable, and instead of fixing and using display devices included in the related art, such as desktops, carrying the display device increases contact with the human body, especially human hands. It became. In addition, while the touch method of the display replaces the conventional analog button method, the hygienic importance of glass, which is a key component of the display device, is increasing, while the hygienic treatment of the glass requires the use of chemicals separately. Problems have arisen, or the hassle that has to be cleaned frequently. Accordingly, the antibacterial treatment of glass has emerged as a serious problem, and thus, various methods for maintaining the antibacterial property of the glass without the use of chemicals and without frequent cleaning are faced with the necessity.

On the other hand, as a method for antibacterial treatment, in the present invention was to apply the glass strengthening method, first, looking at the glass strengthening method, it is known that there is a thermal strengthening, chemical strengthening, physical strengthening method and the like. Among these, chemical strengthening is reported to have the advantages of similar stress distribution to crystallized glass, a moderate stress gradient, and no rapid transition from compression to tension.

A typical chemical strengthening method is the ion exchange method, which converts alkali ions such as Li ⁺ and Na ^{+ on the} surface of the glass into alkali ions such as Na ⁺ and K ⁺ having a larger ion radius and the same charge. It is a method of increasing the strength by forming a compressive stress as the volume of the glass surface is increased by substitution.

Such an ion exchange method generally refers to a case where a molten salt immersion method is used. The molten salt immersion method is a method of strengthening glass by immersing glass in an alkali molten salt and exchanging molten salt-containing ions and glass-containing ions. First, the glass to be ion-exchanged is heated at a transition temperature of 300 to 450 ° C or lower. On the other hand, after melting an alkali salt at the temperature of 380 degreeC or more, it is a method of ion-exchange by depositing the glass heated previously to this molten salt, and holding it for a fixed time or more.

However, such a molten salt immersion method must be equipped with a device for heating the glass in advance and a molten salt bath separately, thereby increasing the size and complexity of the equipment, and heating processes such as ion exchange or preheating must be intermittently without continuity, Depending on the immersion order of the glass to be replaced, a difference in the holding time for strengthening may occur, which may cause a difference in the degree of ion exchange, and a difference in the ion concentration to be substituted for the molten salt may be caused by repeated ion exchange processes. Therefore, the ion exchange conditions need to be corrected, or molten salt needs to be replaced and reheated, resulting in a complicated process.

In addition, in the ion exchange process using molten salt, the salt is heated at a specific temperature and the glass is deposited to proceed with the ion exchange process. Even though the salt is heated and completely melted, the temperature in all parts (positions) of the molten salt bath is increased. It is difficult to see the same, and thus this causes a problem that the temperature, which is the most important condition of ion exchange, varies depending on the location, and thus, it was difficult to stably implement the same final physical properties.

In addition, considering the process temperature and the holding time, the ion exchange process for infiltrating the antibacterial component such as Ag or Cu by molten salt has a relatively high temperature and holding time in the range of 300 to 450 ° C. There was also an uneconomical problem in terms of temperature and maintenance time for about 1 hour.

In addition, the ion exchange process by molten salt is difficult to see evenly distributed concentration of ions of Ag or Cu in all parts of the molten salt bath. The concentration of the ions distributed is difficult to achieve the same physical properties, which also has a problem of lowering the yield for the normal final product.

On the other hand, in performing the ion exchange process, there are certain limitations in terms of the strength or light transmittance of the ion-exchanged glass, and thus, it is necessary to derive a more desirable process element to overcome these limitations. .

In addition, the sol coating method was used in the present invention, conventionally has not been attempted for the process of providing antimicrobial by preparing an antimicrobial material alone and coating it for the antibacterial treatment. Specifically, a coating method using a sol has existed for a long time. The sol is a suspension in which colloidal or inorganic single-molecule solid molecules are dispersed, and when the conditions are selected, the glass is compared to the melting method. It is possible to synthesize at a much lower temperature, and it is possible to sinter the ceramics at a much lower temperature than using conventional raw materials. In addition, the production efficiency is improved because the film can be easily formed without the need for expensive additional equipment such as vacuum equipment, and the film can be simply formed by heat treatment. In addition, because of the characteristics of the sol, starting from the solution, the raw materials are mixed at the molecular level and the atomic level in the multi-component system, so that a film having a homogeneous composition can be easily obtained. Sol coating methods include dip coating, spin coating and spray coating, and have been widely used in many fields. Based on these advantages, the sol coating method has been considered as a method that can easily give antimicrobial properties to coating targets by using antimicrobial materials such as Ag and Cu due to oligodynamic effects.

However, conventional techniques have been used to prepare a composite sol in which Ag is mixed with SiO ₂ sol, instead of Ag alone sol, in order to impart antimicrobial activity by the sol coating method. This also applies to the case of Cu. This is because simply forming Ag by sol alone causes a problem of stabilization such as precipitation, and thus it is not possible to obtain a high quality Ag sole sol enough to impart desired functionality through coating. Thus, SiO ₂ sol, which has very stable thermal characteristics in the air, was prepared, and a small amount of Ag was mixed to solve the instability when Ag was in its sole state. But this attempt introduces another problem. That is, a problem arises in that the coating film must be thickened to satisfy the conventional purpose of utilizing the antibacterial activity of Ag. Since the complex sol is prepared for stability, the amount of Ag contained is very small. Therefore, in order to have the desired antimicrobial activity, the thickness of the film had to be increased to increase the amount of Ag. Conventional techniques are forming a film about 1 μm, which is not suitable in view of the fact that it may cause a decrease in light transmittance for application to a display glass that requires an antimicrobial function in recent years. In addition, conventional composite sols in which SiO ₂ sol is mixed with Ag are required to have a high heat treatment temperature of about 500 ° C. or more in order to obtain a stable film. Such high heat treatment temperatures cause industrial problems in terms of processing time and thus yield. Finally, the conventional composite sol has a problem in terms of unit cost because it must be prepared with SiO ₂ sol to give the antibacterial ability using Ag.

The present invention has been made in order to solve the problems described above, the present invention by providing the antimicrobial performance to the glass, by using the product related to the life of applying the glass, to remove the anxiety of the infection to bacteria in advance The purpose is to make it possible.

In addition, the present invention can be carried out on at least one surface of the glass substrate in advance to remove the flaw present in the glass as much as possible to prevent the loss of light transmittance which was a problem after the ion exchange or to maintain the light transmittance level before and after the ion exchange To do so for other purposes.

In addition, the present invention is antibacterial, unlike the condition that the ion exchange is changed due to the order of immersion in the same sequence in the ion exchange method by the molten salt immersion, the change of the ion concentration of the substitution target in the molten salt according to the repeating process, The object to be treated glass substrates can be antibacterial while maintaining the same conditions to the maximum, and the other object is to reduce the defect rate and increase the yield of glass by antibacterial treatment of the glass substrates under the same conditions.

The present invention is to recognize and solve the disadvantage that the conventional molten salt immersion method is intermittently proceeded to the preheating process and the immersion process for ion exchange, since the ion exchange can proceed continuously from coating to ion exchange, It has a great advantage in the process, and it is characterized in that the process proceeds simultaneously or continuously until the antibacterial treatment.

In addition, another object of the present invention is to increase the reliability of the product by allowing the final glass substrate antimicrobial treated by the same ion exchange process to have the same antimicrobial performance as a whole.

In addition, with the recent trend of eco-friendly and well-being, the nature of glass, an eco-friendly material, and the expansion of the mobile display market and the spread of smartphones and tablet PCs, many devices are using touch-based operation systems. In light of the environment in which it is used, it is another object to maintain the cleanliness of the display area itself in touch-based devices, but in particular to establish optimum ion permeation conditions by ion exchange, a new method. do.

In addition, the present invention includes a small amount of Ag by presenting a coating technology using a single sol of Ag or Cu, unlike the conventional composite sol coating method to give the antibacterial ability of Ag or Cu to the glass through the sol coating method Another object is to produce antimicrobial glass that contains much higher amounts of Ag or Cu than the complex sol.

This means that even when the film is thinner than the composite sol, it can produce the same antimicrobial effect as when the conventional composite sol is thickly coated.

In addition, another object of the present invention is not to lower the light transmittance of the glass by imparting antimicrobial properties to the glass by thin film formation.

In another aspect, the present invention is to provide an antimicrobial treated glass excellent in processing time and yield since the heat treatment temperature after drying of the coated film is possible even at about 220 ℃ because the temperature is much lower than when using a conventional composite sol. .

In addition, since the present invention is a very expensive TEOS precursor for the production of SiO ₂ sol, it is possible to achieve a cost reduction in the antibacterial treatment of glass by preparing Ag and Cu alone sol without using it. For other purposes.

In order to achieve the above object, the present invention is to ion-exchange silver or copper-based materials on at least one surface of the glass substrate by a solid or liquid coating method or by coating a solution containing silver or copper-based materials as a single component. Provided is an antibacterial treatment method of glass for antibacterial treatment of a glass substrate.

Preferably, the step of etching the at least one surface of the glass substrate prior to the antimicrobial treatment to remove the oxide film and microcracks on the surface of the glass substrate.

As a result of removing the oxide film and the microcracks through the etching, a glass having a light transmittance value of 90 to 92% is manufactured.

The silver or copper-based material is preferably a solution containing a powder, a pulverized product, and a sol of silver nitrate or copper nitrate.

In the step of the antibacterial treatment, the heating rate is 8 to 15 ° C. per minute when the temperature is raised to the ion exchange temperature, and the heating history includes applying a holding time of more than 0 minutes and 10 minutes or less at a temperature of 240 to 280 ° C. It is preferable to carry out the process.

It is preferable to contact or apply silver or copper-based material only on one surface of the glass substrate.

In addition, the present invention provides a glass prepared by the method as described above, the antimicrobial treatment by ion exchange having a light transmittance value of 90 ~ 92%.

According to the present invention as described above, by providing antimicrobial performance to the glass, in using the product related to life, the effect of the effect of removing the anxiety of the infection to the bacteria is expected.

In addition, in processing the glass, in addition to the polishing method, by introducing an etching method of the glass, it is possible to prevent the light transmittance from being lost even after ion permeation or sol coating for antibacterial treatment.

In addition, unlike the ion strengthening by the molten salt immersion method that requires the equipment to be built separately, there is no need to build a separate complex or large equipment other than the heat treatment equipment, it is possible to simplify the equipment, simplify the process.

In other words, unlike the ion strengthening by the molten salt immersion method that requires the equipment to be constructed separately, it is not necessary to construct a separate complex or large equipment other than the heat treatment equipment, and the process up to ion exchange can be continuously performed. This can simplify equipment and simplify the process.

In addition, by solving the problem that the degree of antibacterial treatment of glass due to the concentration gradient according to the molten salt bath in the molten salt immersion method can improve the reliability of the glass product.

The process of ion exchange by the solid phase coating method or the liquid phase coating method according to the present invention is achieved within 10 minutes at relatively lower temperatures of 260 ° C (Ag +) and 230 ° C (Cu +), so that the effect of unit cost and yield is excellent. have.

In addition, the ion exchange by the solid phase coating method or the liquid phase coating method shows a higher yield than the molten salt method, which is a conventional ion exchange method, due to the stable temperature gradient of the furnace used during ion exchange.

The conventional molten salt method is complicated in its process and requires a long time of several hours to several tens of hours for effective ion exchange, and thus has low productivity, and has a problem such as deterioration of ion exchange reaction by adsorption of impurities. For application, most of the glass used in the LCD has a thickness of about 0.4 mm, and the size is large, causing a problem of distortion. In addition, ion exchange of the entire glass may affect the circuit coated on one surface of the glass, making it difficult to operate. Since impurities contained in the ion exchange solution may cause fine corrosion on the surface of the glass after ion exchange, ions of the glass may occur. There is a limitation to using it as an exchange method. There is also a need to develop a system that can cope with changes in the concentration of molten salt due to ion exchange in mass production processes. In order to solve this problem, first, we found the optimized ion exchange conditions and anticipated the problems in the production process to establish the process conditions for producing the antimicrobial glass finished products with uniform optical properties.

In addition, in addition to ion exchange, by preparing a sol alone with an antimicrobial material and coating it, the process may be simplified by further eliminating the heat treatment process according to ion exchange. Particularly, when sol is used, the amount of ions added is relatively smaller than that of the solid phase coating method. Therefore, considering the phenomenon that light transmittance is affected to some extent by ion exchange, the sol coating method is more effective in terms of light transmittance. May be more advantageous.

That is, the present invention, unlike the conventional composite sol coating method to impart the antibacterial ability of Ag or Cu to the glass through the sol coating method, Ag is contained in a small amount by presenting a coating technology using a single sol of Ag or Cu It is possible to produce antibacterial glass containing much larger amount of Ag or Cu than the complex sol. This means that even when the film is thinner than the composite sol, it can produce the same antimicrobial effect as when the conventional composite sol is thickly coated.

In addition, the present invention can prevent the light transmittance of the glass from being lowered by imparting antibacterial property to the glass by thin film formation.

In addition, the present invention, since the heat treatment temperature after drying of the coated film is also possible at about 220 ℃ because the temperature is much lower than when using a conventional composite sol has an excellent effect and process time and yield.

In addition, since the present invention is a very expensive TEOS precursor for producing SiO ₂ sol, it is possible to achieve a cost reduction in the antibacterial treatment of glass by preparing Ag and Cu alone sol without using it.

1 is a process chart showing the flow from processing of the glass substrate to ion exchange according to an embodiment of the present invention.
2 is a graph showing ion exchange conditions according to a preferred embodiment of the present invention.
3 to 5 are graphs showing the distribution of K + ions and Ag + ions in the glass substrate surface under ion exchange conditions corresponding to Table 7, which is a preferred embodiment of the present invention.
6 to 8 are graphs showing the distribution of K + ions and Ag + ions in the glass substrate surface under ion exchange conditions corresponding to Table 9, which is a preferred embodiment of the present invention.
9 and 10 are graphs showing light transmittances obtained by etching glass substrates in a NaOH solution according to a preferred embodiment of the present invention.
11 and 12 are photographs showing the glass and the antibacterial treatment according to an embodiment of the present invention, the antimicrobial evaluation results of the treated Salmonella and E-coli culture.
13 and 14 are reinforced by glass according to one embodiment of the present invention, the antimicrobial treatment by the sol coating method of the solid phase coating method and the liquid coating method, respectively, the antimicrobial evaluation results of the cultured Staphylococcus aureus by treating the bacteria The picture shown.
FIG. 15 shows that when a sol is prepared by using silver and copper as sole components according to an embodiment of the present invention, it is applied to a glass substrate by a method not by an ion exchange method and exposed to Staphylococcus aureus for 1 minute. It is a photograph showing the antimicrobial activity.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments.

In the present invention, various variables have been considered in order to make the antimicrobial treatment of glass more economical and effective, and in particular, it is intended to derive a manufacturing method that considers the treatment speed, the size of the system for treatment, etc. in consideration of the mass production process. In the antimicrobial treatment process of the glass of the present invention described below, each process forms an organic bonding relationship with each other.

The present invention is particularly intended for antimicrobial treatment of glass for small display devices such as mobile phones and laptops, but the shape processing is completed, but considering the antibacterial treatment method of a large amount of antimicrobial glass. However, the present invention should not be construed as being limited to the glass for such a small display device, and it should be noted that the glass may be applied regardless of its use.

In short, the present invention is characterized in that the solid phase coating method and the liquid phase coating method are applied to improve the problems of the melt immersion method for ion permeation, and an etching method for reinforcing optical properties such as light transmittance is introduced. .

Here, the solid phase coating method is defined as a process of ion-exchanging salts from a glass surface by contacting a solid salt with glass, and the solid salt is used as a powder, but is not limited to powder. In addition, the liquid coating method is defined as a process of applying a liquid phase to the glass surface and ion exchange. In addition, the sol coating method is to impart antimicrobial performance to the glass by coating without ion exchange, it should be conceptually separated from the liquid coating method.

Figure 1 shows a process chart from the processing of the glass substrate to ion exchange in order to manufacture the antimicrobial glass according to an embodiment of the present invention.

<Production of Glass Substrate>

The composition and physical properties of the mother glass substrate used for reinforcement and / or antibacterial in the present invention are shown in Table 1 below.

Chemical composition
(wt.%) 70-73 SiO ₂ , 13-15 Na ₂ O, 7-12 CaO, 1.0-1.9 Al ₂ O ₃ ,
1.0 ~ 4.5 MgO, 0.02 TiO ₂ , 0.08 ~ 0.14 Fe ₂ O ₃ Glass transition temperature (℃) 500 Refractive Index 1.51 Softening temperature (℃) 730 Hardness (H _v ) 549.7 Transmittance (%) 91.83 (370-700 nm) Fracture toughness (MPam)  0.7144 Reflectance (%) 4.13 (single face) 3-Point Bending Strength (MPa) 151.5

The mother glass substrate having the composition and physical properties as described above was processed to evaluate by strengthening and antibacterial treatment. The glass was then antibacterial by ion exchange using a solid or liquid coating method. The details are as follows.

1. Processing

Glass substrates were processed to be embedded in alumina boats for antibacterial treatment.

2. washing and drying

The cut glass substrate was ultrasonically washed with ethanol and distilled water and then blown with N ₂ gas and dried at 100 ° C. for 10 minutes in a drier.

3. Polishing

The cutting edges and the surfaces were polished using SiC abrasive cloth (# 400, 600, 800, 1000, 1200, 1500, 2000, 2400, 4000) to remove the fine cracks generated at the edges of the cut glass substrate. .

4. washing and drying

The polished mother glass substrate was ultrasonically washed with ethanol and distilled water and then blown with N ₂ gas, and dried in a drier at 100 ° C. for 10 minutes.

5. Etching

The washed and dried mother glass substrate was etched by immersion in an aqueous solution of about 0.2 N concentration of hydrochloric acid (HCl) for about 30 seconds. Here, since the etching solution and concentration can be applied in various ways, the above etching solution and concentration is not limited to the above solution and concentration.

In connection with the etching process, after reducing the microcracks of the surface due to the etching and the antimicrobial treatment and measuring the light transmittance as described later, the excellent light transmittance compared to the light transmittance measured in the non-etched state Indicated.

6. Washing and drying

The etched glass substrates were ultrasonically washed with ethanol and distilled water and then blown with N ₂ gas and dried at 100 ° C. for 10 minutes in a drier.

In the present invention, both a polishing process and an etching process for glass are performed, and both etching and polishing correspond to a process for removing flaw present in the glass substrate. However, the two processes have obvious differences, and the features of the present invention exist in recognizing these differences and in introducing and applying the etching and polishing processes, respectively. The polishing process is to remove cracks and flaws at the edges of the glass substrate, and the etching is carried out for the purpose of removing flaws on the surface. The breakdown of the glass by impact propagates from where the crack is and basically starts from the surface. Therefore, the purpose of polishing and etching are both flaw removal, but the difference is that the flaw does not target the same flaw. In addition, the intention to not lower the light transmittance even after the antibacterial treatment by ion exchange by polishing the edges through the polishing process is a fact that is not known at all in the glass processing process and is not applied in the general field. Given the industrial reality, the performance of these two processes will ultimately prevent the loss of light transmittance values even after ion exchange of glass substrates for antimicrobial treatment. Therefore, the introduction of such a process forms one of the core ideas of the present invention.

<Ion exchange>

The present invention is the core of the invention to maintain or improve the light transmittance of the glass substrate from the combination process of the etching process and the ion exchange process so that the antimicrobial treated glass commercializes as a display use at all, the etching process in this process In both the and the ion exchange process, the process progression method and the process system were simplified in mind, and therefore, the aim is to produce a glass substrate having excellent light transmittance while being suitable for mass production processes. Therefore, the provision of antimicrobial properties of the glass by etching and ion exchange should be regarded as a specific feature of the present invention.

In order to antibacterial to the glass substrate by the ion exchange method, as the solid phase coating method, the glass substrate was embedded in the powder in the state of containing AgNO ₃ powder in an alumina square tray, from which the upper surface of the glass substrate was Both the underside and the underside were treated with antibacterial treatment. At this time, the AgNO ₃ powder was applied to both sides of the glass substrate by 20g, and then glass antibacterial treatment was performed by ion exchange method under the following temperature conditions. However, the coating amount of the AgNO ₃ powder is not limited as described above, and in this embodiment, the powder is applied once and the entire amount of the powder is discarded after ion exchange is completed.

In addition, ion-exchange may be performed by a liquid coating method which prepares a material having antibacterial activity such as AgNO ₃ instead of the solid phase coating method and coats it on the surface of the glass. Such a liquid coating method, for example, may be prepared by preparing a sol with respect to a substance having antibacterial activity such as AgNO ₃ , coating it on a glass surface, and performing ion exchange according to an ion exchange temperature schedule. However, this method of coating is for the state of the material to be applied, and the resulting physical properties are about the same, so the following specific ion exchange process will mainly describe the solid phase coating method.

On the other hand, antibacterial glass was prepared separately or together with strengthening by ion exchange, and after placing the glass substrate in an alumina square tray for antimicrobial test through the production of antibacterial glass, AgNO ₃ powder was placed on the upper surface of the placed glass substrate. The cross-coating was performed by 10 g each to carry out an ion exchange process.

Here, AgNO ₃ was used as a starting material for the purpose of specifically selecting Ag as a material exhibiting antimicrobial properties, but it is not limited to AgNO ₃ , and all possible Ag salts will be targeted as starting materials. . In addition, in order to exhibit antimicrobial properties, it may be used in place of Cu salts, and Cu (NO ₃ ) ₂ may be used corresponding to AgNO ₃ . For reference, Cu (NO ₃ ) ₂ is more advantageous than AgNO _{3 in terms of} manufacturing cost. However, since the ion exchange process and the ion exchange mechanism are almost similar for both Ag and Cu, the experiment and result data for Cu ion exchange are replaced by the experiment and result data for Ag ion exchange.

On the other hand, in the manufacturing process of the antimicrobial glass according to the present invention, in particular, the use of the application method (including solid, liquid) can be described from the following contents. Among the materials used for antibacterial treatment, for example, when Ag ions are ion-exchanged by the molten salt method, it is difficult to coat only one surface of the glass of the touch screen by ion-exchanging the entire glass. Since the other side of the display glass is located on the opposite side of the touch surface, it is derived from the technical idea that the antibacterial treatment is not necessary. Therefore, when the coating method is used, since only one side of the display glass can be treated with antibacterial, the process economy becomes more advantageous. However, it should not be limited to antibacterial treatment on only one side.

In the process, the ion exchange by the coating method is near the melting point (KNO ₃ : 334 ° C, AgNO ₃ : 212 ° C, Cu (NO ₃ ) ₂ : 256 ° C) of AgNO ₃ and Cu (NO ₃ ) ₂ powder for antibacterial use. It is ion exchanged by diffusion process by applying heat. Even if a large amount of powder is applied to one side, the glass sinks when the powder melts and covers the glass substrate. Therefore, in the case of ion exchanged glass coated with only one side to give antimicrobial properties, powder is applied in the square alumina tray and fixed plates are placed at both ends of the glass (not shown) to prevent the glass from sinking after powder melting so that both sides are ion exchanged. You can do that. That is, such an application method is much easier to antibacterial treatment on only one surface than the ion exchange method by the melting method. However, exactly one side of the antibacterial glass is prepared by KNO ₃ , AgNO ₃ for antibacterial and Cu (NO ₃ ) ₂ as a solution containing a sol form and coated on one side of the glass substrate using a spin coater. Can be obtained by heat treatment.

In addition, if ion exchange is applied not only through Ag + ions but also Cu + ions with low raw materials, the ion exchange can be selectively performed on one side after strengthening. 100% antimicrobial activity against bacteria such as aureus. In particular, by dividing into 1min, 5min, 60min, etc., it is possible to secure the price competitiveness by securing the optimal conditions of ion exchange which shows antimicrobial effect in a short time. This will be described later.

In performing the ion exchange process for the strengthening or antibacterial treatment, the ion exchange temperature, the ion exchange heat treatment schedule and the ion exchange time were considered as the main variables. This will also be described later.

More specific ion exchange process and evaluation of the ion exchanged glass can be described as follows.

In the present invention, the antibacterial and light transmittance were confirmed by ion exchange for 1 to 10 minutes at 240 ~ 280 ℃ with AgNO ₃ powder. Meanwhile, when Cu (NO ₃ ) ₂ powder is used instead of AgNO ₃ powder, the ion exchange temperature may be lowered to about 225 ° C. based on the commercially available temperature as glass. Moreover, even if ion exchange is carried out by keeping time less than 1 minute, there is no big problem in antibacterial treatment.

In addition, summarized the properties of the salt used for ion exchange in the present invention are shown in Table 2 below.

type Silver nitrate Molecular formula AgNO ₃ M.P. 212 ℃ B.P. 444 ℃ Solubility in water 0.36kg / L (20 ℃) density 4.35 g / cm3 (16 ° C)

In addition, the ion exchange conditions carried out by way of example in the present invention are shown in FIG. 2. This shows the heat treatment schedule required to give antimicrobial properties of glass substrates by ion exchange.

As shown, the temperature increase rate required to reach the ion exchange temperature was set to a value of 10 ℃, 20 ℃ per minute, it was experimentally derived that it is desirable to maintain the preferred temperature increase rate at a value of 8 ~ 15 ℃ per minute. . At this time, a glass having a light transmittance of 90 to 93% and an intensity of 600 to 630 MPa based on the glass subjected to the etching treatment could be produced.

Faster heating rate means faster passage through the non-target temperature, which would mean reducing ion exchange time at a temperature other than the target temperature during heating. Similarly, slowing the rate of heating may be thought to further increase the ion exchange time at other temperatures during the heating.

Therefore, the temperature increase rate schedule is an important factor in ion exchange. In the antibacterial treatment of glass by ion exchange, it is possible to increase the temperature increase rate so that Ag + ions do not penetrate deeply into the surface. Have a better effect. However, if the rate of heating is too high, it can be concluded that the Ag + ions do not sufficiently exchange on the glass surface, so it can be concluded that scheduling an appropriate rate of heating will produce good results.

Such critical ion exchange temperature and temperature increase rate can be derived from the critical significance, which will be described in the evaluation of the reinforced or antimicrobial glass produced by the present invention as described below.

<Antibacterial treatment method by application of solution containing silver or copper as a single component>

In addition, the present invention relates to a method for preparing antimicrobial treatment by preparing a solution containing silver or copper as a sole component and not by ion exchange. To this end, in the present invention, as an example of the solution, silver nitrate and copper nitrate were prepared as a sol and applied to a glass substrate to perform antibacterial treatment. Silver nitrate sol and copper nitrate sol were prepared using ethanol and water as solvents, respectively, and the prepared solvents were pH-controlled to derive optimal dispersion conditions.

First, after various methods were attempted to prepare the silver nitrate sol, it was found that the sol that can be applied to the glass substrate was prepared by containing 0.3 to 1.5 mol% of silver nitrate based on 100 mol% of the total sol. .

However, when the use of the antibacterial glass according to the present invention is a display glass, the light transmittance should be considered. A glass for use could be prepared.

The light transmittance of the silver nitrate sol was prepared on the basis of the case where the light transmittance was 90% or more based on the etched glass substrate, and as a result, it is desirable to include 0.3 to 0.8 mol% of silver nitrate in the solution. Could be derived.

This light transmittance will be described later.

In addition, after various methods have been tried to prepare a copper nitrate sol, it is possible to prepare a sol that can be applied to a glass substrate by containing 2.5 to 3.5 mol% of copper nitrate based on 100 mol% of the total sol. Could know.

Copper nitrate of such a content is determined in consideration of the light transmittance similar to silver nitrate, and shows a light transmittance of 90% or more in the above range, which will also be described later.

On the other hand, in the preparation of the sol, both the silver nitrate and the copper nitrate satisfy the dispersion conditions, contribute to the stabilization of the sol, make the coating smooth, and as a result, the light transmittance and the antimicrobial treatment can be evenly distributed. As a result of adjusting the pH to derive, it was found that the pH is preferably adjusted to have a value of 1.0 to 1.5.

<Evaluation of Optical and Antibacterial Properties by Ion Exchange>

Through the ion exchange process carried out as described above, the optical and antimicrobial properties of the glass substrate given antimicrobial properties were evaluated. We also found out. Table 3 below shows the evaluation items, evaluation purpose and equipment used for evaluation.

Evaluation item Purpose of Evaluation Equipment used Light transmittance Measurement of transmittance by ion exchange (visible light range: 370 ~ 800nm) UV / Vis. / NIR spectrometer
(Jasco, V-570, Japan) Ion penetration depth K ⁺ , Ag ⁺ penetration depth by ion exchange Electron probe micro analyzer
(JXA-8900R, JEOL, Japan) Microstructure Microstructure of Ion Exchange Interface Scanning electron microscope (SEM, Hitachi S-3000M, Japan) Antibacterial test Review of antimicrobial activity against used bacteria: ISO 22196 Film adhesion type (used strain: Salmonella, Escherichia coli, etc.)

1. Light transmittance measurement

In order to investigate the optical properties of the glass by ion exchange, the light transmittance of the specimens before and after ion exchange at 200-800 nm was measured using a UV-VIS-NIR spectrophotometer (V-570, JASCO, Japan). For example, when a glass substrate is used for a display device, such light transmittance is a very important property to be dealt with, and if the light transmittance is lowered due to the strengthening or antimicrobial properties of the glass, a serious limitation in the use of the glass may occur. Therefore, consideration should be given to the provision of the light transmittance and the strengthening and antibacterial properties of the glass.

delete

(1) Light Transmittance Characteristics of Ion Exchange Enhancement and Simultaneous Antimicrobial Activity by Ion Exchange

Next, to strengthen the glass substrate by a method of mixing the potassium nitrate (KNO ₃ ) powder AgNO ₃ powder according to an embodiment of the present invention for the strengthening by an embodiment of the present invention, and ion exchange using the same. And to give the antimicrobial (including the glass substrate given only the antimicrobial of the serial number 2-5 in the table below) and measured the light transmittance value thereof is shown in Table 4 below. This is the light transmittance including the etching process.

Serial Number Ion Exchange Conditions K + penetration depth (μm, up / down)
Ag + penetration depth (μm, up / down) K + input amount (%, up / down)
Ag + input amount (%, up / down) Light transmittance
(%) 2-1 450 ° C./15 minutes 18.9 / 23.1
38.6 / 41.3 99.99 / 99.99
0.01 / 0.01 91.87 2-2 450 ° C./15 minutes 22.5 / 29.7
37.0 / 42.1 99.95 / 99.95
0.05 / 0.05 91.25 2-3 450 ° C./15 minutes 18.8 / 22.9
44.1 / 56.1 99.50 / 99.50
0.50 / 0.50 90.23 2-4 450 ° C./15 minutes 17.5 / 18.3
58.4 / 62.3 99.00 / 99.00
1.00 / 1.00 90.05 2-5 450 ° C./15 minutes 17.8 / 14.5
85.5 / 122.7 0.00 / 0.00
100.00 / 100.00 91.08 2-6 450 ° C./15 minutes 17.5 / 31.7
0 / 48.5 0.00 / 99.50
0.00 / 0.50 90.67

Here, as the ion exchange conditions, the temperature means the ion exchange temperature, and the time in minutes means the holding time required for the ion exchange, respectively. The temperature as ion exchange conditions in this embodiment is an ion exchange temperature necessary for strengthening.

3 to 5 show graphs of distributions of K + ions and Ag + ions in the glass substrate surface under ion exchange conditions corresponding to Table 4 above.

As can be seen from Table 4 and FIGS. 3 to 5, the glass substrates at which K + and Ag + were ion-exchanged at the same time generally did not lower the light transmittance value to 90% or less. This results in little difference from the light transmittance value before ion exchange, which is believed to be due to the effect of removing flaw by etching the glass.

However, in particular, the antimicrobial property of the glass for display devices may be applied only to one surface exposed to the outside. Therefore, both surfaces of the glass substrate may be strengthened as shown in the serial number 2-8 of Table 4 above, but only Ag may be used on one surface. It is preferable to perform ion exchange.

In the next section, the separation of glass substrates by ion exchange and the antibacterial treatment by ion exchange were separated.

That is, the problem of ion exchange due to powder mixing is caused by the difference between the melting points of the two salts used during ion exchange. The KNO ₃ melting point is 334 ° C and AgNO ₃ is 212 ° C. When the heat treatment is performed in the process, the penetration depth of Ag + ions becomes deeper when the process is performed separately. In the range of 0.01 to 5wt% of Ag powder, the penetration depth is 38.6 ~ 84.2㎛ and the penetration depth of Ag ions exceeds the penetration depth of K ions. Therefore, it is necessary to perform mixed ion exchange under the optimum conditions considering the penetration depth of Ag ions and the penetration depth of K ions.

(2) Light transmittance characteristics when antimicrobial properties were given by ion exchange after ion exchange strengthening of glass

Next, the glass substrate is strengthened by ion exchange at 450 ° C. for 15 minutes using KNO ₃ powder according to one embodiment of the present invention, and subsequently by ion exchange at various temperatures necessary for ion exchange of Ag + using AgNO ₃ powder. After giving the antimicrobial properties to the glass substrate, the light transmittance value was measured and shown in Table 5 below. In view of the foregoing, it is more preferable that Ag ions penetrate only the cross section of the glass substrate, so that Ag ion penetrates only the cross section. It is to be noted that the present invention has an inventive feature that can very easily implement the process of ion permeation only in cross section.

Serial Number Ag + ion exchange conditions K + penetration depth (μm, up / down)
Ag + penetration depth (μm, up / down) Light transmittance (%) 3-1 240 ℃ / 2 minutes 18.0 / 21.5
0.0 / 0.0 91.37 3-2 240 ℃ / 5 minutes 17.4 / 19.4
0.0 / 0.0 91.47 3-3 240 ℃ / 10 minutes 18.8 / 22.9
0.0 / 0.0 91.51 3-4 250 ℃ / 2 minutes 18.7 / 19.5
0.0 / 0.0 91.36 3-5 250 ° C / 5 minutes 17.2 / 28.2
0.0 / 0.0 91.23 3-6 250 ° C / 10 min 16.7 / 17.7
0.0 / 3.5 90.31 3-7 255 ° C / 1 minute 17.2 / 18.5
0.0 / 0.4 91.32 3-8 260 ℃ / 0min 16.8 / 18.1
0.0 / 0.5 91.19 3-9 260 ° C / 1 min 17.0 / 17.5
0.0 / 0.8 91.08

Here, as the ion exchange conditions, the temperature means the ion exchange temperature, and the time in minutes means the holding time required for the ion exchange, respectively. Serial numbers 3-7 to 3-9 in Table 5 are intended to find out the light transmittance characteristics of the glass substrate derived therefrom by very short holding time required for ion exchange as a minimum Ag + ion permeation experiment.

6 to 8 are graphs showing distributions of K + ions and Ag + ions in the glass substrate surface under ion exchange conditions corresponding to Table 5 above.

After the glass substrate was ion-exchanged at 450 ° C. for 15 minutes using KNO ₃ powder, the Ag + ion permeation amount was confirmed by AgNO ₃ powder according to the ion exchange temperature and time change. As shown in Table 5, the minimum penetration depth was obtained at 255 ° C. / 1 minute. Indicated. Ag + The minimum ion exchangeable temperature of ions was found to be 250 ℃ or more. On the other hand, it was also found that the minimum ion exchangeable temperature of Cu 2+ ions was about 240 ° C.

As can be seen from Table 5 and FIGS. 6 to 8, penetration of Ag + by ion exchange hardly occurred until the retention time of 240 ° C. and 250 ° C. for 5 minutes. However, it was found that ion exchange by Ag + occurred at a temperature of 250 ° C. for 10 minutes and higher. Note that there was almost no change in the light transmittance values after the ion exchange with Ag +. Compared with Table 4 above, when ion exchange with K + and ion exchange with Ag + are performed simultaneously, or ion exchange with Ag + is sequentially performed after ion exchange with K +, or one surface of a glass substrate If only the Ag + ion exchange is carried out it can be seen that it has a similar level of light transmittance value. Therefore, in view of the simplicity of the process, it may be advantageous to mix the KNO ₃ and AgNO ₃ to proceed the strengthening and antimicrobial at the same time. However, in view of the process temperature, it may be considered that there is economical process because it is sufficient to lower the ion exchange temperature of Ag +. At this time, the ion exchange conditions for the antimicrobial treatment will be said to be carried out in the range of more than 0 and 5 minutes or less in the temperature range of 240 ~ 280 ℃ in terms of strength. The above range is critical for implementing such strength values. On the other hand, in the case of using, Cu (NO _{3) 2} as described above may be represented, considering the melting point of Cu (NO _{3) 2} ion-exchange conditions in the temperature range of 225 ~ 280 ℃.

In short, as can be seen from Tables 4 and 6 above, in the case of ion exchange by mixing KNO ₃ and AgNO ₃ , it can be seen that the light transmittance decreases as the amount of Ag + ions exchanged increases. However, this is not an unsuitable degree for commercialization, and such light transmittance values are meaningful by themselves. However, when only one surface of the glass substrate is strengthened and antibacterial, and ion exchange is applied to both surfaces of the glass substrate, the total amount of K + ions and Ag + ions is 100%. When the amount was 0.05% or less, light transmittance close to the mother glass could be obtained. In addition, in the step of imparting antimicrobial properties after ion strengthening, the light transmittance close to the light transmittance of the mother glass can be obtained by giving the antibacterial treatment to the end surface. In this case, however, the penetration depth of Ag + was very small.

On the other hand, when Ag + ions were infiltrated at temperatures of 250, 255, 260, 270, and 280 ° C, the penetration rates were 0.35, 0.40, 0.80, 0.98, 1.20 / min, which was 260 ° C, indicating the ion exchange antimicrobial activity of Ag +. In case of 1min ion exchange, Ag means 0.8 per minute penetration into the glass surface, and it is a condition for producing antimicrobial glass with little decrease in light transmittance. On the other hand, although not shown, in the case of Cu2 +, ion exchange at 225 ℃ and 230 ℃, showed an antimicrobial effect without lowering the light transmittance, as described above.

In addition, when the ion exchange holding time was maintained within 10 minutes, the antimicrobial effect and the ion penetration depth of Table 12 of Ag + were obtained.

From this, the ion exchange conditions that can maintain the light transmittance at a commercially available level, when the temperature range of 225 ~ 270 ℃ and ion exchange time conditions of less than 0 seconds and 10 minutes or less, the present invention can be optimized.

Therefore, at 450 and 15 minutes, which is the optimal ion exchange strengthening condition, it is possible to selectively manufacture multifunctional (antibacterial, tempered, light transmittance) tempered glass when ion exchanged with an antimicrobial effect and a minimum penetration depth of Ag ions. can do.

9 and 10 show the light transmittance as a result of etching in NaOH solution.

If the above is about light transmittance before etching, the depicted shows the light transmittance after strengthening of the etched glass substrate. As shown, it can be seen that the light transmittance exhibits a light transmittance in the range of 90 to 94% improved over the light transmittance of the mother glass. Therefore, it can be said that the etching of the present invention corresponds to a process capable of realizing excellent light transmittance as glass applications.

(3) Light transmittance characteristics after coating on a glass base material using silver or copper as a single component

As described above, as a result of preparing the sol using silver or copper-based material and applying it to the glass substrate, the antimicrobial treatment resulted in the light transmittance as shown in Tables 6 and 7. Here, the coating film was stabilized on the glass substrate by heat treatment at a temperature of about 220 ° C.

Concentration of Ag in sol Light transmittance (%) 0.2 mol% 89.44 0.3 mol% 91.13 0.4 mol% 90.97 0.5 mol% 90.95 0.6 mol% 90.62 0.7 mol% 90.27 0.8 mol% 90.14 0.9 mol% 87.52

Concentration of Cu in the sol Light transmittance (%) 2.3 mol% 88.94 2.5 mol% 90.95 2.8 mol% 90.82 3.0 mol% 90.76 3.2 mol% 90.41 3.5 mol% 90.07 3.8 mol% 89.03

As can be seen from Tables 6 and 7, above, Ag exhibited a light transmittance of about 90% or more in the range of 0.3 to 0.8 mol%, and Cu in the range of 2.5 to 3.5. However, even if it is outside the above range may have an antibacterial effect. In addition, as described above, even when Ag exceeded 0.8 mol%, the coating performance by spin coating was excellent unless the factor of light transmittance was taken into consideration.

In the case of silver nitrate sol, the concentration of Ag is too small at the concentration of 0.3 mol% or less, so the viscosity of the sol becomes low, making it difficult to raise the film through spin coating. In addition, if the concentration of Ag is too low, the proportion of ethanol is relatively high. Increasing the ratio of ethanol may cause more evaporation of ethanol, which has a lower boiling point from the membrane during drying. It is expected to cause damage to the membrane. Thus, this prevents obtaining a good quality film.

In addition, when the concentration of Ag is too high at a concentration of 1.5 mol% or more, the viscosity of the sol becomes high, making it difficult to uniformly disperse and coat the sol on the glass surface by spin coating. In addition, the most important factor in the present invention has been described above as the stability of the sol, in view of this, nitric acid is not stable, such as the precipitation of the sol before the coating when the sol is produced at a concentration of 1.5 mol% or more. As can be seen, the concentration range of silver nitrate as above is of critical significance.

In addition, when Cu is dissolved in ethanol, the viscosity tends to be higher than that of Ag. Therefore, when the concentration of copper nitrate becomes higher than 3.5 mol%, as described above, the copper does not spread evenly on the glass surface during spin coating. Done. This means that a good antimicrobial membrane cannot be obtained after drying and heat treatment. In addition, when the sol is made so that the concentration of copper nitrate is less than 2.5 mol%, EtOH, which occupies a relatively large proportion when viewed as a whole, evaporates a lot during drying and heat treatment, thereby lowering the film quality.

Therefore, the concentration of copper nitrate is also critical in the above range.

3. Antimicrobial Evaluation

11 and 12 show the results of the antimicrobial evaluation of the glass substrate imparted by the present invention. Antimicrobial evaluation was evaluated by analyzing the antimicrobial activity (log) of the ion exchanged glass substrates for salmonella typhimurium bacteria (FIG. 11) and E-coli bacteria (FIG. 12) by film adhesion method according to ISO 22196. More specifically, sallmonella typhimurium and E-coli bacteria were put in petri dish, respectively, and cultured in 37 incubators for 24 hours, and then the antimicrobial activity was evaluated by checking the antimicrobial activity against ion exchange glass. As a result, it was shown that the antibacterial activity of the glass ion-exchanged for Ag 260 ° C., 1 min, and Cu 230 ° C., 1 min, which was tested separately, was 100%, respectively.

In addition, the antimicrobial evaluation of the Staphylococcus aureus bacteria of the glass substrate given the antimicrobial properties according to the present invention was shown in Figures 13 and 14. In this case, the antimicrobial activity of the Staphylococcus aureus bacteria was observed for 1 minute as a result of Ag and Cu ion exchange under the aforementioned ion exchange conditions. As shown, the antimicrobial activity of each glass was found to be close to 100%.

In addition, Figure 15 shows the antimicrobial activity when the sol was prepared using silver and copper as the sole component and applied to a glass substrate by a method of application rather than an ion exchange method and exposed to Staphylococcus aureus for 1 minute. The reinforcement process is omitted here.

As shown, it can be seen that the excellent antibacterial performance also by the sol coating method.

Here, the above results are intended to show the same results as the antimicrobial treatment with glass strengthening or antimicrobial treatment without strengthening. In other words, despite the reinforcement, the antimicrobial performance did not decrease at all.

Other experimental results are not shown, but it can be seen that the antimicrobial activity of 99% or more by the ion-treated antimicrobial glass in the range of 225 ~ 280 ℃.

Claims (10)

Mechanically polishing the edges and edge surfaces of the glass substrate to remove flaw;
Etching at least one surface of the glass substrate from which the edge flaw is removed to further remove oxide films and microcracks on the surface of the glass substrate;
Antimicrobial treatment of the glass substrate by applying a silver or copper-based material to at least one surface of the glass substrate by a coating method of a solution containing silver or copper-based material as a single component,
The solution containing the silver or copper material as a sole component is silver nitrate or copper nitrate, and the silver nitrate is 0.3 to 0.8 mol% when the sol is 100 mol%, and the copper nitrate is 2.5 to 3.5 when the sol is 100%. Mole%,
The silver nitrate solution and copper nitrate solution to adjust the pH in the range of 1 to 1.5,
Light transmittance is 90 to 92% of the antimicrobial treatment method of glass. The method of claim 1,
In the step of antibacterial treatment of the glass substrate to a heating rate of 8 ~ 15 ℃ per minute, performing a heating process including a heating history of applying a holding time of more than 0 minutes and less than 10 minutes at a temperature of 240 ~ 280 ℃ The antibacterial treatment method of glass characterized by the above-mentioned. The method of claim 1,
The antimicrobial treatment method of the glass characterized by contacting or applying silver or copper-based material only on one surface of the glass substrate. delete delete delete delete delete delete delete

Images