A copper-loaded flexible antibacterial glass and its preparation method

Abstract

The present invention provides a copper-loaded flexible antibacterial glass and a preparation method thereof. The copper-loaded flexible antibacterial glass contains 1% - 2% monovalent copper ions as antibacterial metal ions. The preparation method includes the following steps: The binary composite chloride salt used is CuCl and KCl, and it is melted at 350°C ≤ T0 ≤ 400°C. The flexible glass is preheated at 350°C ≤ T0 ≤ 400°C; the preheated flexible glass is put into the molten antibacterial molten salt for ion exchange for 3 - 10 minutes. After the ion exchange is completed, it is cooled to obtain the copper-loaded flexible antibacterial glass. The advantages are that the obtained copper-loaded flexible antibacterial glass does not warp or crack, the transmittance of the flexible glass changes little before and after ion exchange, and at the same time, the antibacterial rate R > 95%. At the same time, the technical solution of the present invention has simple and environmentally friendly process, short time consumption, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of glass manufacturing, and particularly to a flexible antibacterial glass loaded with copper antibacterial molten salt and a preparation method thereof. Background Art

[0002] As a key substrate for display products, with the rapid development of the display industry, electronic glass is constantly tending to be larger, thinner, and lighter. Its sheet size has experienced a generational change from 5G to 11G, and its thickness has decreased from 0.7 mm to 0.4 mm, and even towards 0.2 mm. Flexible glass with a thickness ≤ 0.1 mm has emerged under this background. With the advent of the "Internet +" era, people's lives are becoming increasingly closely related to handheld electronic devices, and the application of flexible glass has become more and more extensive. When people touch the screen, sweat and oil on the body will adhere to the screen, which provides favorable conditions for the reproduction of bacteria. If these devices are all made of flexible antibacterial glass materials, many adverse effects brought by bacteria can be reduced. Therefore, the research on flexible antibacterial glass is of great significance.

[0003] Currently, the mainstream antibacterial glass products on the market are silver-loaded antibacterial glass. However, due to the very active chemical properties of silver, it is easy to undergo redox reactions in the glass to form silver atoms, and the silver atoms will agglomerate with silver ions to form silver particle clusters (such as Ag2 + –Ag 0 +Ag + 、Ag 2+ –Ag + +Ag + etc.). When the size of the silver particle clusters increases, the glass will be colored, the transmittance of the silver-loaded glass will decrease, which has high requirements for the control of the production process, and the price of silver ion raw materials is high, resulting in high production costs. Monovalent copper ions and divalent copper ions both have good antibacterial properties. In order to improve the transmittance of antibacterial glass and reduce production costs, some manufacturers use copper antibacterial to produce copper-loaded antibacterial glass.

[0004] When introducing copper ions as antibacterial molten salt, it is often a mixture of CuSO4 and sulfates, such as a mixture of one or more of Na2SO4 and K2SO4. For example, Chinese Patent 112209634, an antibacterial molten salt, glass and its preparation method, discloses an antibacterial molten salt containing copper sulfate and sodium sulfate.

[0005] Because the melting point of sulfates is high, the melting point of the sulfate mixed molten salt is relatively high. The relatively high exchange temperature is likely to cause warping and cracking of the flexible glass during ion exchange. Moreover, divalent copper ions are prone to coloring the glass, and using copper sulfate for exchange is likely to cause the glass to change color, seriously affecting the transmittance of the flexible glass. Summary of the Invention

[0006] The object of the present invention is to solve the above problems, and to provide a copper-loaded flexible antibacterial glass and its preparation method, which solve the disadvantages of high melting point of existing antibacterial molten salts, low transmittance of the prepared flexible antibacterial glass, and easy discoloration.

[0007] The present invention adopts the following technical solutions:

[0008] I. The present invention first provides a copper-loaded flexible antibacterial glass, wherein the antibacterial metal ions contained in the copper-loaded flexible antibacterial glass are monovalent copper ions, and the percentage content of copper element on the glass surface is 1% - 2%.

[0009] II. The present invention also provides a preparation method of the above-mentioned copper-loaded flexible antibacterial glass,

[0010] 1). An antibacterial molten salt is adopted, and the antibacterial molten salt is a binary composite chloride salt. The antibacterial metal ions in the binary composite chloride salt are monovalent copper ions. The binary composite chloride salt is a mixture of CuCl and KCl, and its molar ratio is CuCl 40% - 45% and KCl 55% - 60%;

[0011] 2) The method for the copper-loaded flexible antibacterial glass includes the following steps:

[0012] Melting: Melting the antibacterial molten salt at a temperature T0, 350°C ≤ T0 ≤ 400°C;

[0013] Preheating: Preheating the flexible glass at T0;

[0014] Ion exchange: Putting the preheated flexible glass into the molten antibacterial molten salt at a temperature of T0 for ion exchange, and after the ion exchange is completed, cooling to obtain the above-mentioned copper-loaded flexible antibacterial glass.

[0015] In the ion exchange step, the ion exchange time is 5 - 10 min.

[0016] The antibacterial rate R of the prepared copper-loaded flexible antibacterial glass is > 95%, and the transmittance is above 90%.

[0017] In the above technical solution, a molten salt with a low melting point is required to reduce the warping of the glass during the exchange process. Since the absorption limit of monovalent copper ions coincides with the absorption limit of the glass itself and it is not easy to color the glass, the antibacterial ions in the molten salt are mainly monovalent copper ions. The present invention provides an antibacterial molten salt, wherein the antibacterial metal ions in the antibacterial molten salt are monovalent copper ions, and the antibacterial molten salt is a mixed molten salt of chloride salts, and its binary phase diagram is as Figure 2 shown.

[0018] The antibacterial metal ions in the antibacterial molten salt are monovalent copper ions. The antibacterial molten salt does not contain other antibacterial ions such as silver ions and zinc ions. The antibacterial metal ions are provided by CuCl. Since the cost of using pure CuCl molten salt is relatively high, other molten salts can be introduced to reduce the cost on the one hand and lower the melting point of the mixed molten salt on the other hand.

[0019] The antibacterial molten salt of the present invention adopts a copper chloride mixed molten salt because the copper chloride molten salt has a lower melting point than the copper sulfate molten salt, and the absorption limit of Cu + ions coincides with the absorption limit of the glass. Therefore, the glass containing Cu + ions has little absorption of visible light, high glass transmittance, and is not easily colored.

[0020] The molten salt selected through experiments is a binary mixed molten salt of copper chloride and potassium chloride. To ensure that Cu + has sufficient energy for exchange, the exchange temperature T0≥350 °C; to reduce costs, the content of copper chloride in the mixed molten salt should be reduced as much as possible.

[0021] The present invention conducts ion exchange with chlorides of different ratios, selects a suitable chloride ratio, and selects the optimal exchange temperature.

[0022] Through experiments, the optimal exchange temperature of the molten salt is 350 - 400 °C. In the range of 350 - 400 °C, the CuCl / KCl mixed molten salt is in a molten state, and the substrate glass can perform ion exchange in the molten salt.

[0023] Through experiments, the optimal molar ratio of the molten salt is that the content of CuCl is 40% - 45%, and the rest is KCl.

[0024] Preferably, the optimal molar ratio of the antibacterial molten salt is CuCl 40% - 45%, KCl 55% - 60%, and the exchange temperature is 350 - 400 °C.

[0025] The antibacterial molten salt provided by the present invention is applicable to flexible cover glass of various handheld devices.

[0026] The advantages of the present invention are as follows: Different from the existing technologies, the above technical solution at least achieves the following purposes: By introducing a binary chloride mixed molten salt containing monovalent copper ions, through the composition design of the binary chloride, it can be melted at a temperature of 350 - 400 °C, facilitating the antibacterial ion exchange of mainstream glass in the industry. After ion exchange, the copper ions exist in the glass in a monovalent state, and the glass is colorless and transparent. When the exchange time is 5 - 10 minutes, the copper element content on the surface of the copper-loaded glass is between 1% and 2%, and the distribution depth of the copper element is between 20 and 30 μm. The glass transmittance hardly changes before and after antibacterial; the antibacterial rate R value > 95%. At the same time, the process of the present invention is simple, takes less time, and is very suitable for industrial production. Description of the Drawings

[0027] Figure 1 are the transmission spectra of copper-loaded glass at different times in the embodiment;

[0028] Figure 2 is the KCl-CuCl binary phase diagram. Detailed Description of the Invention

[0029] To describe in detail the technical content, structural features, achieved objectives and effects of the technical solution, the following is a detailed description with specific examples.

[0030] The glass used in the present invention is all flexible glass produced by China National Building Material Kaisheng Group, with a thickness of 50 μm, and the mass percentage composition is as follows: SiO2 55 - 65%, Al2O3 15 - 20%, Na2O 7 - 15%, K2O 1 - 5%, MgO 5 - 10%, CaO 0.1 - 2%, ZrO2 0.1 - 1%. It is prepared by the following method:

[0031] First, a molten salt with a molar ratio of CuCl:KCl = 4:6 is mixed evenly.

[0032] The evenly mixed binary antibacterial molten salt is placed in a corundum crucible and melted in the range of 350°C ≤ T0 ≤ 400°C, and is reserved after becoming molten.

[0033] The flexible glass sample is preheated in a muffle furnace at a preheating temperature of T0. After preheating, the glass is put into the mixed molten salt for ion exchange. The exchange time is shown in Table 1. After the exchange, the glass is taken out, and after cooling and cleaning, copper-loaded flexible antibacterial glass can be obtained. Then, performance tests are carried out. The test items and results are compared in Table 1, and the transmission spectrum is as Figure 1 .

[0034] Table 1 Performance table of copper-loaded flexible glass after exchange

[0035] Exchange time / min Surface copper element concentration / wt% Copper element distribution depth / μm Transmittance / % Antibacterial rate / % 0 0 0 92.03 0 2 0.2 15 92.03 >90 5 1.2 19 91.89 >95 10 1.9 40 91.88 >95

[0036] It can be seen from the data in Table 1 that when the exchange time is 5 minutes, the antibacterial rate of the obtained copper-loaded antibacterial glass can reach the requirements of excellent products (R ≥ 95%). Moreover, using the molten salt exchange method described in the present invention to prepare copper-loaded antibacterial glass not only has a lower exchange temperature, but also the obtained copper-loaded glass has a higher surface copper element content and a deeper copper element diffusion depth, and the transmittance of the obtained glass sample is almost unchanged compared with the original sheet.

[0037] The definitions, explanations or test methods of the physical properties in Table 1 are as follows:

[0038] (1) Exchange temperature T0: The melting temperature of the binary mixed molten salt, obtained from the corresponding KCl-CuCl binary phase diagram and experiments;

[0039] (2) The surface copper element content and the depth of copper element distribution are measured by an energy dispersive spectrometer (EDS).

[0040] (3) Transmittance: Measured by an ultraviolet-visible spectrophotometer.

[0041] (4) Antibacterial rate R: Using the method in Standard JC / T 1054–2007, by surface inoculating a suspension containing bacteria, after 24 hours of inoculating bacteria on the antibacterial product and the untreated product, subtract the number of bacteria obtained from the antibacterial product (B) from the number of bacteria obtained from the surface of the untreated product (A), and then divide by the number of bacteria obtained from the surface of the untreated product, and convert it to a percentage.

[0042] It can be seen from Figure 1 that there is no characteristic absorption at 500 nm - 800 nm in the copper-loaded antibacterial glass, indicating that there is no Cu 0 and Cu 2+ or the content is extremely small, and almost all of the copper element exists in the form of Cu + form.

[0043] The specific implementation mode has the following advantages:

[0044] (1) In the present invention, a copper-loaded antibacterial layer is prepared on the flexible glass by ion exchange. The ion exchange method has a simple process and advantages such as low cost and easy operation.

[0045] (2) The molten salt used in the present invention is a mixed molten salt of cuprous chloride and potassium chloride. This molten salt not only has a low melting point and is not easy to cause warping and cracking of the flexible glass substrate during the exchange process, but also the absorption limit of monovalent copper ions coincides with the absorption limit of the glass itself, and will not have a great impact on the transmittance of the flexible glass.

Claims

1. A preparation method of copper-loaded flexible antibacterial glass, characterized in that: 1) An antibacterial molten salt is used, and the antibacterial molten salt is a binary composite chloride salt. The antibacterial metal ion in the binary composite chloride salt is a monovalent copper ion. The binary composite chloride salt is a mixture of CuCl and KCl, and the molar ratio thereof is CuCl 40% - 45%, KCl 55% - 60%; 2) The preparation method includes the following steps: Melting: Melting the antibacterial molten salt at temperature T0, 350°C ≤ T0 ≤ 400°C; Preheating: Preheating the flexible glass at temperature T0; Ion exchange: Placing the preheated flexible glass into the molten antibacterial molten salt at temperature T0 for ion exchange, the ion exchange time is 5 - 10 min. After the ion exchange is completed, it is cooled to obtain copper-loaded flexible antibacterial glass. The antibacterial metal ion contained in the copper-loaded flexible antibacterial glass is a monovalent copper ion, and the percentage content of copper element on the glass surface is 1% - 2%; The obtained copper-loaded flexible antibacterial glass has an antibacterial rate R > 95% and a transmittance of more than 90%; The flexible glass has a thickness of 50 μm, and the composition mass percentages are as follows: SiO2 55 - 65%, Al2O3 15 - 20%, Na2O 7 - 15%, K2O 1 - 5%, MgO 5 - 10%, CaO 0.1 - 2%, ZrO2 0.1 - 1%.

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