Chemical strengthening process for reducing warpage of float glass

Abstract

The invention provides a chemical strengthening process for reducing warpage of float glass, which comprises the following steps: cutting a glass substrate, and carrying out thickness test; after cutting and processing the glass, cleaning and drying; the dried glass is subjected to chemical strengthening and cleaning; testing the performance of the strengthened glass; the glass substrate is selected from electronic float glass with the thickness of 0.33 mm to 1.1 mm; the chemical strengthening temperature ranges from 370 DEG C to 410 DEG C, and the time ranges from 1 h to 2 h; and the tin permeation amount of the glass is 5.5-7.0 ug / cm < 2 >. According to the method, the warping degree of the glass is optimized by controlling the tinning amount, the strengthening time and the temperature of the glass with specific components and thicknesses. The process method provided by the invention is simple and easy to realize, and can effectively reduce the warping of the ultrathin float glass in the ion strengthening process.

Description

Technical Field

[0001] The present application relates to the field of float glass preparation, and in particular to a chemical strengthening process for reducing the warping of float glass. Background Art

[0002] In today's society, informatization and intelligence are gradually advancing, and higher requirements are also put forward for smart devices (smart phones, tablets, smart watches, etc.). While satisfying people's ability to receive information, higher requirements are also put forward for the strength of mobile portable terminal devices. Therefore, it is necessary to produce high-strength, wear-resistant, drop-resistant, and explosion-proof device protection screens. After chemical strengthening, traditional float glass significantly improves the anti-bending, drop-resistant, and explosion-proof properties of the glass. The essence of chemical strengthening is to use high-concentration salt to exchange ions on the glass, and replace the metal ions with smaller radii in the glass with alkaline metal ions with large radius at high temperature, so that the glass produces greater surface stress to achieve the purpose of improving the strength of the glass. Chemical strengthening can well improve the compressive, bending, drop-resistant, and wear-resistant properties of the glass itself, but during the chemical strengthening process, warping will occur, resulting in a significant reduction in the flatness of the glass, so that it cannot fit well with mobile terminal devices, which not only affects the aesthetics of the product, but also reduces the comfort of the device. Therefore, reducing the warping of chemically strengthened glass is a prerequisite for its good application. Summary of the invention

[0003] The purpose of the present application is to overcome the defects existing in the prior art and provide a chemical strengthening process for reducing the warping of float glass. The present application proposes a chemical strengthening process for reducing the warping of float glass which is easy to implement, low in cost and effective, and the present invention explores the specific chemical strengthening conditions that can satisfy both high glass strength after chemical strengthening and low warping.

[0004] The present application provides a chemical strengthening process for reducing the warpage of float glass, characterized in that it comprises the following steps: cutting a glass substrate and performing a thickness test; after cutting and processing the glass, cleaning and drying it; chemically strengthening and cleaning the dried glass; and performing a performance test on the strengthened glass; the glass substrate is selected from electronic float glass with a thickness of 0.33 mm to 1.1 mm; the chemical strengthening temperature is 370° C. to 410° C., and the time is 1 to 2 hours; the tin penetration amount of the above glass is 5.5 to 7.0 ug / cm 2 .

[0005] In some embodiments, the electronic float glass components, measured by mass percentage, include: SiO2 60% to 68%, Al2O3 10% to 20%, Na2O 5% to 12%, K2O 0 to 1%, MgO 0.1 to 5%, CaO 0 to 5%, and ZrO2 1.5% to 3.5%; wherein the total mass fraction ratio of Na2O and K2O is not less than 10%.

[0006] In some embodiments, the glass substrate is cut into a size of 166.17*75.0 mm, and / or in step 1, the thickness difference of the glass after cutting is less than 0.1%.

[0007] In some embodiments, the glass in step 1 is subjected to CNC processing.

[0008] In some embodiments, the chemical strengthening temperature is 380° C. and the time is 2 hours.

[0009] In some embodiments, the chemical strengthening solution is KNO3.

[0010] In some embodiments, the concentration of the chemical strengthening solution is 800-1000 ppm.

[0011] In some embodiments, the chemically strengthened glass cleaning is ultrasonic cleaning, and the ultrasonic cleaning solution is NaOH, citric acid, glass cleaning agent, and pure water.

[0012] In some embodiments, the ultrasonic cleaning solution is sequentially NaOH, citric acid, glass cleaning agent, and pure water, or sequentially citric acid, NaOH, glass cleaning agent, and pure water.

[0013] In some embodiments, each ultrasonic cleaning is performed for 5-10 minutes in an ultrasonic cleaning solution.

[0014] The present invention optimizes the degree of glass warping by controlling the tin infiltration amount, strengthening time and temperature of glass with specific composition and thickness. The process method proposed by the present invention is simple and easy to implement, and can effectively reduce the warping of ultra-thin float glass during ion strengthening. DETAILED DESCRIPTION

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the description and claims of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0016] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0017] In order to solve the problem raised in the background technology, the present application provides a chemical strengthening process for reducing the warpage of float glass, characterized in that it comprises the steps of:

[0018] Cut the glass substrate and perform thickness test;

[0019] After cutting and processing the glass, it is cleaned and dried;

[0020] The dried glass is chemically strengthened and cleaned;

[0021] Conduct performance tests on tempered glass;

[0022] The glass substrate is selected from electronic float glass with a thickness of 0.33 mm to 1.1 mm;

[0023] The chemical strengthening temperature is 370°C-410°C and the time is 1-2h;

[0024] The tin penetration of the above glass is 5.5-7.0ug / cm 2 .

[0025] In the present application, the glass is cut to select the glass without broken edges and defects; the cut glass is selected with a micrometer to select the glass with uniform thickness for processing; the thickness difference is kept at a low level to ensure that the warping of the glass before tempering is small; the glass is CNC processed to ensure the appearance and performance of the processed product and the processing procedure is accurate.

[0026] The present application aims at improving the warpage of glass with a specific thickness by controlling the strengthening temperature, strengthening time, and the amount of tin infiltration into the glass.

[0027] In some embodiments, the electronic float glass components, measured by mass percentage, include: SiO2 60% to 68%, Al2O3 10% to 20%, Na2O 5% to 12%, K2O 0 to 1%, MgO 0.1 to 5%, CaO 0 to 5%, and ZrO2 1.5% to 3.5%; wherein the total mass fraction ratio of Na2O and K2O is not less than 10%.

[0028] In some embodiments, the glass substrate is cut into a size of 166.17*75.0 mm, and / or the thickness difference of the cut glass is less than 0.1%.

[0029] In some embodiments, the glass in step 1 is subjected to CNC processing.

[0030] In some embodiments, the chemical strengthening temperature is 380°C and the time is 2h. In the chemical strengthening process of glass, temperature and time are two key parameters, which have a significant impact on the strengthening effect of glass and the subsequent warping phenomenon. When the chemical strengthening temperature is set to 380°C and the time is 2 hours, the benefits of improving the warping of glass in this application are mainly reflected in the following aspects: 380°C is a moderate temperature, which can ensure that the smaller alkali metal ions in the glass are fully exchanged with the larger alkali metal ions in the salt bath, and will not cause excessive softening or deformation of the glass due to excessive temperature; 2 hours of treatment time is enough for the ion exchange reaction to reach an equilibrium state, thereby forming a stable and effective compressive stress layer on the glass surface. Chemical strengthening under appropriate temperature and time conditions helps to distribute the compressive stress on the glass surface more evenly and reduce the warping phenomenon caused by uneven stress distribution. A large compressive stress layer is formed on the surface of the chemically strengthened glass, which can effectively improve the wear resistance and impact resistance of the glass. In addition to reducing warping, appropriate chemical strengthening treatment can also improve the heat and cold resistance of the glass and increase its stability under extreme temperature conditions.

[0031] In some embodiments, the chemical strengthening solution is KNO3.

[0032] In some embodiments, the concentration of the chemical strengthening solution is 800-1000 ppm

[0033] In some embodiments, the chemically strengthened glass cleaning is ultrasonic cleaning, and the ultrasonic cleaning solution is NaOH, citric acid, glass cleaning agent, and pure water.

[0034] In some embodiments, in some embodiments, the ultrasonic cleaning solution is sequentially NaOH, citric acid, glass cleaning agent, and pure water, or sequentially citric acid, NaOH, glass cleaning agent, and pure water.

[0035] Strong alkaline solutions are highly corrosive and react chemically with acidic dirt and organic matter, effectively removing these dirt. Using NaOH first can remove most dirt and grease on the surface of the object, laying the foundation for subsequent cleaning steps. Citric acid, an organic acid solution, is relatively mild and can be used to remove insoluble dirt and sediment. After the NaOH cleaning, citric acid can further remove residual dirt and alkaline residues that may be generated by NaOH without causing damage to the object. Glass cleaners, cleaning agents designed for materials such as glass, may contain ingredients such as surfactants and chelating agents to remove stains on the glass surface and improve cleanliness. After the citric acid cleaning, using glass cleaners can ensure that the glass surface is cleaner and clearer and remove any remaining dirt or chemical residues. Pure water: free of impurities and chemicals. As a final rinse step, pure water can remove all cleaning agents and residues to ensure a clean and stain-free surface. The above citric acid and NaOH solutions can be interchanged in order.

[0036] In some embodiments, each ultrasonic cleaning is performed for 5-10 minutes in an ultrasonic cleaning solution.

[0037] [Example]

[0038] The present invention uses two batches of glass of the same thickness. The raw material composition, formula and production line process of the two batches of glass are consistent. The only difference is that the tin infiltration amount of the two batches of glass is different. The instrument used in the present invention for testing the tin infiltration amount is XRF.

[0039] In the present invention, KNO3 solution is used for chemical strengthening to explore K + The influence of the change of concentration on the strengthening effect can also be used to explore effective methods to improve the warping of glass. + It is 800-1000ppm. Based on the test data, a method to improve the warpage is proposed, and the instrument used for the ion concentration test is I CP.

[0040] It can be understood that the above-mentioned testing methods and equipment are commonly used methods for evaluating glass-related properties in the industry. They are only a means to characterize or evaluate the technical scheme and technical effects of the present invention. Other testing methods and testing equipment can also be used to perform the same test, and the test results do not affect the final results.

[0041] The preparation process of the chemically strengthened glass provided in Examples 1-10 and Comparative Examples 11-20 is as follows:

[0042] Float glass with a thickness of 0.33 mm was manufactured using the traditional float glass manufacturing process and cut to the required size. Two batches of glass were chemically strengthened at different temperatures and times. After strengthening, their warpage and stress properties were tested.

[0043] The same batch of glass of the present invention is chemically strengthened at 370-410°C for 1-2 hours. The same batch and 10 examples are tested under the same conditions. The test data are averaged as one example and listed below. 10°C is a temperature gradient and 1 hour is a time gradient. Table 1-2 is the data of Examples 1-10 and Comparative Examples 11-20.

[0044] It should be noted that when Example 1-10 is chemically strengthened, K + The concentration is 800-1000ppm; at the same time, in Examples 1-10, the tin penetration amount of the glass used is 6.5ug / cm 2 The tin penetration amount of the glass used in Examples 11-20 is 5.5ug / cm 2 ;

[0045] In actual tests, small changes in ion concentration have no effect on the test results. + The change in concentration can be ignored. In the data comparison of Examples 1-20, the change rate of the tin infiltration amount in the present invention is close to 15%. Therefore, the change in the tin infiltration amount needs to be considered when comparing the data of the examples of the present invention.

[0046] Table 1 Tin penetration amount is 6.5ug / cm 2 Time data test results

[0047]

[0048]

[0049] Based on Examples 1-10, it can be clearly seen in the present invention that, as the temperature decreases, at the same chemical strengthening time, the stress value and ion exchange depth of the test glass, whether it is the air side or the tin side, are decreasing. In other words, the temperature reduction will lead to a weakening of the chemical strengthening effect, thereby affecting the degree of ion exchange.

[0050] By comparing Examples 1-4, it can be seen that under the same chemical strengthening time, the lower the temperature, the worse the ion exchange effect, and at the same time, the difference between the CS and DOL of the tin surface and the air surface becomes smaller, that is, the difference in the degree of ion exchange between the tin surface and the air surface is smaller. From the perspective of stress, the decrease in temperature will lead to a decrease in the warpage of Examples 1-4, which can be intuitively seen from the warpage values ​​of Examples 1-4.

[0051] Similarly, in the three groups of embodiments 6-10, 11-15, and 16-20, the present invention adopts a fixed chemical strengthening time and changes the chemical strengthening temperature. As a control, the influence of the chemical strengthening temperature on the chemical strengthening effect is explored. It can be obtained that within the same chemical strengthening time, as the temperature decreases, the chemical strengthening effect becomes worse, the difference in CS and DOL values ​​between the tin surface and the air surface becomes smaller and smaller, and the warpage of the glass after chemical strengthening becomes smaller.

[0052] Table 2 Tin penetration amount is 5.5ug / cm 2 Time data test results

[0053]

[0054]

[0055] By comparing Examples 1 and 6, it can be found that, at the same chemical strengthening temperature, the shorter the chemical strengthening time, the worse the chemical strengthening effect, and at the same time, the smaller the difference between CS and DOL, the smaller the warping of the example. This is because shortening the chemical strengthening time leads to a narrowing of the difference in chemical strengthening effect between the tin surface and the air surface, thereby achieving the effect of reducing the warping of the example.

[0056] By comparing Example 1 with Example 11, Example 2 with Example 12, Example 3 with Example 13, and Example 4 with Example 14, it can be found that under the same chemical strengthening temperature and time, the tin penetration amount is 5.5ug / cm 2 The tin penetration amount of Examples 11-15 is 6.5ug / cm 2 In Examples 1-4, under the same chemical strengthening conditions, the smaller the tin infiltration amount, the smaller the difference in CS and DOL between the air side and the tin side of the example, and thus the warping of the example is also smaller. This data demonstrates that a smaller tin infiltration amount will reduce the difference in strengthening effects between the air side and the tin side under the same chemical strengthening conditions, thereby reducing the warping of the example.

[0057] In the present invention, a universal testing machine compression test is used to determine the chemical strengthening effect. By performing a compression test on the coated glass, the bending effects under different chemical strengthening conditions are determined as shown in Table 3.

[0058] Table 3 Four-point bending displacement of Examples 1-10

[0059]

[0060]

[0061] The present invention tests the four-point bending test effects of Examples 1-10 in the chemical strengthening temperature range of 370℃-410℃ and chemical strengthening for 1-2h respectively. By comparing Examples 1 and 6; Examples 2 and 7; Examples 3 and 8; Examples 4 and 9; Examples 5 and 10, it can be obtained that: at the same chemical strengthening temperature, the higher the chemical strengthening temperature, the better the four-point bending test effect, which means the better the anti-bending effect of the float glass. By comparing Examples 1-5 and Examples 6-10, it can be seen that at the same chemical strengthening time, the higher the chemical strengthening temperature, the better the four-point bending test effect, the greater the bending displacement, and the better the effect of chemical strengthening. The warping degree and the bending effect are negatively correlated. The smaller the warping, the poorer the bending, and the larger the warping, the better the bending.

[0062] As is known to all, the brittleness and toughness of materials are opposing physical properties. The purpose of the present invention is to find a suitable chemical strengthening temperature and time to satisfy the chemical strengthening conditions that allow the glass to have higher strength and lower warpage, that is, to have moderate bending resistance and warpage.

[0063] The bending displacement of Examples 1-10 can more intuitively show the chemical strengthening effect of float glass under different chemical strengthening conditions from the data. The present invention combines multiple factors such as CS, DOL, warping, and bending effects in the chemical strengthening effect, and explores that the most suitable chemical strengthening condition of this application is 380°C, 2h. Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be replaced by equivalents without departing from the scope and spirit of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way.

Claims

1. A chemical strengthening process for reducing float glass warpage, It is characterized in that Includes steps: Cut the glass substrate and perform thickness test; After cutting and processing the glass, it is cleaned and dried; The dried glass is chemically strengthened and cleaned; Conduct performance tests on tempered glass; The glass substrate is selected from electronic float glass with a thickness of 0.33 mm to 1.1 mm; The chemical strengthening temperature is 370°C-410°C and the time is 1-2h; The tin penetration of the above glass is 5.5-7.0ug / cm 2 .

2. The chemical strengthening process for reducing float glass warpage according to claim 1, It is characterized in that The electronic float glass components, measured by mass percentage, include: SiO 2 60%~68%,Al 2 O 3 10%~20%, Na 2 O 5%~12%, K 2 O 0~1%, MgO 0.1~5%, CaO 0~5%, ZrO 2 1.5%~3.5%; among which Na 2 O and K 2 The total mass fraction of O is not less than 10%.

3. The chemical strengthening process for reducing float glass warpage according to claim 1, It is characterized in that The glass substrate is cut into a size of 166.17*75.0 mm, and / or in step 1, the thickness difference of the glass after cutting is less than 0.1%.

4. The chemical strengthening process for reducing float glass warpage according to claim 1, It is characterized in that The glass in step 1 is processed by CNC.

5. The chemical strengthening process for reducing float glass warpage according to claim 1, It is characterized in that The chemical strengthening temperature is 380° C. and the time is 2 h.

6. The chemical strengthening process for reducing float glass warpage according to claim 1, It is characterized in that The chemical strengthening solution is KNO 3 .

7. The chemical strengthening process for reducing float glass warpage according to claim 1, It is characterized in that The concentration of the chemical strengthening solution is 800-1000 ppm.

8. The chemical strengthening process for reducing float glass warpage according to claim 1, It is characterized in that Chemically strengthened glass cleaning is ultrasonic cleaning, and the ultrasonic cleaning solution is NaOH, citric acid, glass cleaning agent, and pure water.

9. The chemical strengthening process for reducing float glass warpage according to claim 8, It is characterized in that The ultrasonic cleaning solution is in the order of NaOH, citric acid, glass cleaning agent, and pure water, or in the order of citric acid, NaOH, glass cleaning agent, and pure water.

10. The chemical strengthening process for reducing float glass warpage according to claim 8, It is characterized in that In the ultrasonic cleaning solution, each ultrasonic cleaning was performed for 5-10 minutes.

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