Composite clarifying agent for glass substrate and preparation method of glass substrate

Abstract

The invention discloses a composite clarifying agent for a glass substrate and a preparation method of glass, and belongs to the field of electronic glass production. The composite clarifying agent for the glass substrate is prepared from the following components in parts by weight: 20 to 25 parts of SnO2, 20 to 25 parts of NaCl and 50 to 60 parts of CaF2. The compound clarifying agent does not contain arsenic oxide and antimony oxide, is non-toxic and environment-friendly, and avoids leaching of harmful substances in the storage process. In addition, the adopted CaF2 can play a fluxing role, and melting of refractory materials such as quartz sand and the like is promoted at high temperature. Meanwhile, CaF2 and CaCl2 react and combine with NaCl at the temperature of 1500 DEG C or above, products such as CaCl2 remaining in molten glass are gasified and volatilized, CaF2 and CaCl2 can lower the viscosity of the molten glass and lower the surface tension of the glass at the high temperature, remaining bubbles are further removed, the clarification process is finally completed, and the composite clarifying agent is good in cascade relay clarification effect. Therefore, a product with a better clarification effect is obtained.

Description

Technical Field

[0001] The present invention belongs to the field of electronic glass production, and specifically relates to a composite fining agent for glass substrates and a preparation method of glass. Background Art

[0002] With the rapid development of display technology and 5G technology, the household and commercial display terminals have developed from 55 inches to the current 65 inches, 75 inches and even to larger sizes. As the most important and crucial component material for displays, glass plates have also made great progress, evolving from the initial G3 products to the current G5, G6, G8.5, G10.5 and G11.

[0003] The glass plate for display is an alkali-free aluminoborosilicate glass, which has good thermal stability, chemical stability and high mechanical strength, and is often used as a TFT-LCD glass substrate and an OLED carrier plate. Due to the high melting temperature and high viscosity at high temperature of the alkali-free aluminoborosilicate glass, its fining is very difficult, that is, it is very difficult for the glass melt to remove the visible bubbles present, resulting in bubble defects and low product yield. Therefore, a fining agent needs to be introduced during the preparation process. The fining agent releases gas at high temperature, and through diffusion, the volume of the surrounding bubbles increases, accelerating the rise and finally being removed from the surface of the glass melt.

[0004] Traditional fining agents are mostly oxides of arsenic. Although arsenic has good fining effect, due to its toxicity, it brings a great economic burden to production and treatment. Antimony is a successor substitute for arsenic. Although it can achieve a certain fining purpose and its toxicity is reduced, it is still harmful and expensive, which is not conducive to environmental protection. Currently, the most used fining agent is tin oxide, and its fining effect is good. For example, the patent application with the publication number CN104761141A discloses a fining agent for high-hardness glass, which is made from the following raw materials in parts by weight: mirabilite 3-3.3, persimmon oxide 0.32-0.36, tin oxide 0.4-0.6, Nd2(CO3)3 0.8-0.9, cobalt oxide 0.4-0.6, potassium permanganate 0.3-0.5, sodium fluoride 0.5-0.6, sodium bicarbonate 0.4-0.5, fumed silica 3-5, and silica sol 2-2.5. However, using single tin oxide as a fining agent has limited fining ability, and excessive tin oxide will cause tin defects in the glass plate. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite fining agent for glass substrates and a preparation method of glass substrates. The composite fining agent can effectively reduce the surface tension of the glass, promote glass melting, improve the quality of glass melting, has good fining effect and high glass product yield.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A composite fining agent for glass substrates, by weight, includes 20-25 parts of SnO2, 20-25 parts of NaCl, and 50-60 parts of CaF2.

[0008] SnO2 is a redox fining agent with a melting point of 1630 °C. It can decompose to form stannous oxide (SnO) at high temperatures, and mainly realizes the absorption and release of O2 through the valence change of Sn 2+ When the temperature is low, stannous oxide absorbs oxygen and turns into high-valent tin oxide; when reaching the fining temperature, the oxygen absorbed by tin oxide begins to be released. The oxygen released enters the bubbles in the glass melt, absorbs and combines with other gases in the glass melt, reduces the gas partial pressure in the bubbles, promotes the increase in the volume of the bubbles, and accelerates the rise, thereby achieving the purpose of fining. The reaction equation is as follows:

[0009]

[0010] Calcium fluoride (CaF2), commonly known as fluorite, is a natural ore with a relative molecular mass of 78.08 and a relative density of It is also a commonly used glass fining agent. During the melting process of fluorides, part of the fluorine will become HF, SiF4, NaF, etc., and can also turn harmful impurities such as ferric oxide (Fe2O3) and ferrous oxide (FeO) into ferric fluoride (FeF3) for volatilization and removal or form colorless sodium hexafluoroferrate (Na3FeF6). In the float glass process, calcium fluoride can be used as a flux or a fining agent, etc. It can accelerate the decomposition of the batch material. According to research, adding 1% of fluorine to the glass can increase the melting speed by 15-20% and reduce the softening temperature by 30 °C; at the same time, the fluoride ions in the substrate are beneficial to the etching process of the customer panel manufacturing process. The reaction equation is as follows:

[0011] 2CaF2 + SiO2 = SiF4↑ + 2CaO

[0012] NaCl is a high-temperature volatile fining agent with a boiling point of 1465 °C. It forms [FeCl3] volatiles and volatilizes itself in the glass melt, and reduces the surface tension and viscosity of the glass, playing a fining role. NaCl mainly acts in the heating stage. In the cooling stage, the content of NaCl in the glass melt is not much left, and only a small part remains in the glass melt and bubbles.

[0013] The present invention has found a more suitable combination of fining agents. At the same time, the attempt to add Na + has also changed the previous understanding of the development of future liquid crystal substrate glass: Na + is harmful to the characteristics of the liquid crystal film and cannot be added, etc.

[0014] A method for preparing a glass substrate includes the following steps:

[0015] S1. Mix SnO2, NaCl, and CaF2 evenly to obtain a glass composite fining agent; mix glass raw materials evenly to obtain a glass batch.

[0016] S2. Mix the glass composite fining agent and the glass batch evenly, melt and clarify to obtain glass liquid; form, anneal, and cool to obtain a glass substrate.

[0017] Furthermore, the dosage ratio of the glass composite fining agent to the glass batch is (0.5 - 0.8):(99.2 - 99.5).

[0018] Furthermore, the glass raw materials include SiO2, Al2O3, B2O3, and alkaline earth metal oxides.

[0019] Furthermore, the dosage ratio of SiO2, Al2O3, B2O3, and alkaline earth metal oxides is (56 - 65):(13 - 22):(0.05 - 12):(9 - 24).

[0020] Furthermore, the alkaline earth metal oxides are one or a combination of CaO, MgO, BaO, and SrO.

[0021] Furthermore, the melting and clarification process is to heat from 1100 - 1200 °C to 1550 - 1580 °C at a rate of 6 - 10 °C / min, hold for 1 - 1.5 h, then heat to 1640 - 1650 °C at a rate of 1 - 3 °C / min, hold for 1.5 - 2 h, then cool to 1605 - 1610 °C at a rate of 1 - 3 °C / min, clarify and hold for 20 - 30 min, and then cool to 1600 °C at a rate of 1 - 3 °C / min.

[0022] Furthermore, the forming, annealing, and cooling process is to pour the molten glass liquid into a mold, place it at 730 - 750 °C for annealing, and then cool it to room temperature with the furnace.

[0023] Furthermore, the thickness of the glass substrate is 0.2 - 1 mm, and the plate width is 2000 - 3000 mm.

[0024] Furthermore, the forming process is the overflow method or the float process.

[0025] Since the processes involved in this method, such as mixing, melting, homogenization, forming, and annealing, are all conventional processes in the glass technology field, they will not be elaborated here.

[0026] Advantages of the present invention:

[0027] (1) A composite fining agent for a glass substrate and a preparation method of the glass substrate provided by the present invention. The composite fining agent does not contain arsenic oxide and antimony oxide, is non-toxic and environmentally friendly, and avoids the leaching of harmful substances during storage.

[0028] (2) The CaF2 used in the present invention can play a fluxing role. At 1200°C - 1500°C, it promotes the melting of refractory materials such as quartz sand. Meanwhile, above 1500°C, it reacts with NaCl and combines. The products such as CaCl2 remaining in the glass melt gasify and volatilize. CaF2 and CaCl2 can not only reduce the viscosity of the glass melt at high temperatures, but also reduce the surface tension of the glass, further removing the remaining bubbles, and finally completing the clarification process. This composite clarifier has a good step-by-step relay clarification effect, thus obtaining a product with better clarification effect. Detailed implementation mode

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention.

[0030] Embodiment 1

[0031] This embodiment provides a glass substrate, which is prepared through the following steps:

[0032] S1. Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite clarifier; mix 60 parts of SiO2, 16.5 parts of Al2O3, 5.9 parts of B2O3, 3.1 parts of MgO, 8 parts of CaO, and 6.5 parts of SrO evenly to obtain a glass batch;

[0033] S2. Mix 0.5 part of the glass composite clarifier and 99.5 parts of the glass batch evenly and pour them into a platinum crucible. Heat from 1100°C to 1580°C at a rate of 8°C / min, hold for 1 h, then heat to 1640°C at a rate of 2°C / min, hold for 1.5 h, then cool to 1610°C at a rate of 2°C / min, clarify and hold for 30 min, and then cool to 1600°C at a rate of 1°C / min to obtain a glass melt; then use the float process to cast the molten glass melt into a graphite mold, put the glass into a muffle furnace at 730°C for annealing, and then cool it to room temperature with the furnace to obtain a glass substrate with a thickness of 0.5 mm and a plate width of 3000 mm.

[0034] Embodiment 2

[0035] The difference between this embodiment and Embodiment 1 is that in S2, "mix 0.5 part of the glass composite clarifier and 99.5 parts of the glass batch" is changed to "mix 0.6 part of the glass composite clarifier and 99.4 parts of the glass batch".

[0036] The remaining raw materials and the preparation process are the same as those in Example 1.

[0037] Example 3

[0038] Compared with Example 1, the difference in this example is that in S2, “mix 0.5 part of glass composite fining agent and 99.5 parts of glass batch” is changed to “mix 0.7 part of glass composite fining agent and 99.3 parts of glass batch”.

[0039] The remaining raw materials and the preparation process are the same as those in Example 1.

[0040] Example 4

[0041] Compared with Example 1, the difference in this example is that in S2, “mix 0.5 part of glass composite fining agent and 99.5 parts of glass batch” is changed to “mix 0.8 part of glass composite fining agent and 99.2 parts of glass batch”.

[0042] The remaining raw materials and the preparation process are the same as those in Example 1.

[0043] Example 5

[0044] Compared with Example 1, the difference in this example is that in S1, “mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “mix 21.3 parts of SnO2, 20.4 parts of NaCl, and 58.3 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0045] The remaining raw materials and the preparation process are the same as those in Example 1.

[0046] Example 6

[0047] Compared with Example 2, the difference in this example is that in S1, “mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “mix 21.3 parts of SnO2, 20.4 parts of NaCl, and 58.3 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0048] The remaining raw materials and the preparation process are the same as those in Example 1.

[0049] Example 7

[0050] Compared with Example 3, the difference in this example is that in S1, “mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “mix 21.3 parts of SnO2, 20.4 parts of NaCl, and 58.3 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0051] The remaining raw materials and the preparation process are the same as those in Example 1.

[0052] Example 8

[0053] This example is different from Example 4 in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 21.3 parts of SnO2, 20.4 parts of NaCl, and 58.3 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0054] The remaining raw materials and the preparation process are the same as those in Example 1.

[0055] Example 9

[0056] This example is different from Example 1 in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 23.6 parts of SnO2, 23.3 parts of NaCl, and 53.1 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0057] The remaining raw materials and the preparation process are the same as those in Example 1.

[0058] Example 10

[0059] This example is different from Example 2 in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 23.6 parts of SnO2, 23.3 parts of NaCl, and 53.1 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0060] The remaining raw materials and the preparation process are the same as those in Example 1.

[0061] Example 11

[0062] This example is different from Example 3 in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 23.6 parts of SnO2, 23.3 parts of NaCl, and 53.1 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0063] The remaining raw materials and the preparation process are the same as those in Example 1.

[0064] Example 12

[0065] Compared with Example 4, this example is different in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 23.6 parts of SnO2, 23.3 parts of NaCl, and 53.1 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0066] The remaining raw materials and the preparation process are the same as those in Example 1.

[0067] Example 13

[0068] Compared with Example 1, this example is different in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 25 parts of SnO2, 25 parts of NaCl, and 50 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0069] The remaining raw materials and the preparation process are the same as those in Example 1.

[0070] Example 14

[0071] Compared with Example 2, this example is different in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 25 parts of SnO2, 25 parts of NaCl, and 50 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0072] The remaining raw materials and the preparation process are the same as those in Example 1.

[0073] Example 15

[0074] Compared with Example 3, this example is different in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 25 parts of SnO2, 25 parts of NaCl, and 50 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0075] The remaining raw materials and the preparation process are the same as those in Example 1.

[0076] Example 16

[0077] Compared with Example 4, this example is different in that in S1, “Mix 24.9 parts of SnO2, 22.5 parts of NaCl, and 52.6 parts of CaF2 evenly to obtain a glass composite fining agent;” is changed to “Mix 25 parts of SnO2, 25 parts of NaCl, and 50 parts of CaF2 evenly to obtain a glass composite fining agent;”.

[0078] The remaining raw materials and the preparation process are the same as those in Example 1.

[0079] Comparative Example 1

[0080] S1. Mix 60 parts of SiO2, 16.5 parts of Al2O3, 5.9 parts of B2O3, 3.1 parts of MgO, 8 parts of CaO and 6.5 parts of SrO evenly to obtain a glass batch;

[0081] S2. Mix 0.8 part of SnO2 and 99.2 parts of the glass batch evenly, pour them into a platinum crucible, heat from 1100 °C to 1580 °C at a rate of 8 °C / min, hold for 1 h, then heat to 1640 °C at a rate of 2 °C / min, hold for 1.5 h, then cool to 1610 °C at a rate of 2 °C / min, clarify and hold for 30 min, and then cool to 1600 °C at a rate of 1 °C / min to obtain a glass melt; then use the float process to cast the molten glass into a graphite mold, put the glass into a muffle furnace at 730 °C for annealing, and then cool it to room temperature with the furnace to obtain a glass substrate with a thickness of 0.5 mm and a plate width of 3000 mm.

[0082] The remaining raw materials and the preparation process are the same as those in Example 1.

[0083] Comparative Example 2

[0084] S1. Mix 60 parts of SiO2, 16.5 parts of Al2O3, 5.9 parts of B2O3, 3.1 parts of MgO, 8 parts of CaO and 6.5 parts of SrO evenly to obtain a glass batch;

[0085] S2. Mix 0.8 part of NaCl and 99.2 parts of the glass batch evenly, pour them into a platinum crucible, heat from 1100 °C to 1580 °C at a rate of 8 °C / min, hold for 1 h, then heat to 1640 °C at a rate of 2 °C / min, hold for 1.5 h, then cool to 1610 °C at a rate of 2 °C / min, clarify and hold for 30 min, and then cool to 1600 °C at a rate of 1 °C / min to obtain a glass melt; then use the float process to cast the molten glass into a graphite mold, put the glass into a muffle furnace at 730 °C for annealing, and then cool it to room temperature with the furnace to obtain a glass substrate with a thickness of 0.5 mm and a plate width of 3000 mm. The remaining raw materials and the preparation process are the same as those in Example 1.

[0086] Comparative Example 3

[0087] S1. Mix 60 parts of SiO2, 16.5 parts of Al2O3, 5.9 parts of B2O3, 3.1 parts of MgO, 8 parts of CaO and 6.5 parts of SrO evenly to obtain a glass batch;

[0088] S2. Mix 0.8 parts of CaF2 and 99.2 parts of glass batch evenly and pour them into a platinum crucible. Heat from 1100 °C to 1580 °C at a rate of 8 °C / min, hold for 1 h, then heat to 1640 °C at a rate of 2 °C / min, hold for 1.5 h, then cool to 1610 °C at a rate of 2 °C / min, clarify and hold for 30 min, and then cool to 1600 °C at a rate of 1 °C / min to obtain glass liquid. Then, use the float process to cast the molten glass liquid into a graphite mold, put the glass into a muffle furnace at 730 °C for annealing, and then cool it to room temperature with the furnace to obtain a glass substrate with a thickness of 0.5 mm and a plate width of 3000 mm. The remaining raw materials and preparation process are the same as those in Example 1.

[0089] The remaining raw materials and preparation process are the same as those in Example 1.

[0090] Performance test

[0091] According to the standard of GB 11614-2022, the performance of the glass substrates prepared in Examples 1-16 and Comparative Examples 1-3 was tested, and the results are shown in Table 1:

[0092] Table 1

[0093]

[0094]

[0095] It can be seen from Table 1 that by using the above glass clarifier, it can ensure that the glass liquid can continuously discharge bubbles at different temperature stages, so as to obtain a product with better clarification effect, the number of bubbles per kilogram is not higher than 2, and there are no problems of tiny dense bubbles and streaks.

[0096] The glass clarifier of the present invention does not contain toxic and harmful substances such as As2O3 and Sb2O3, is non-toxic, harmless, safe and environmentally friendly, and the clarifying effect of the glass clarifier is good. The glass prepared by using this glass clarifier has less bubble residue and higher quality.

[0097] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent in such process, method, article or device.

[0098] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite fining agent for glass substrates, characterized in that, By weight, it includes SnO2, NaCl, and CaF2.

2. The composite fining agent for a glass substrate according to claim 1, wherein, The dosage ratio of SnO2, NaCl, and CaF2 is (20 - 25):(20 - 25):(50 - 60).

3. A method for preparing a glass substrate, characterized in that, It includes the following steps: S1. Mix SnO2, NaCl, and CaF2 evenly to obtain a glass composite fining agent; mix the glass raw materials evenly to obtain a glass batch. S2. Mix the glass composite fining agent and the glass batch evenly, melt and clarify to obtain a glass melt; perform forming, annealing, and cooling to obtain a glass substrate.

4. The manufacturing method of a glass substrate according to claim 3, characterized in that The dosage ratio of the glass composite fining agent and the glass batch is (0.5 - 0.8):(99.2 - 99.5).

5. A method for preparing a glass substrate according to claim 3, characterized in that, The melting and clarification process is to heat from 1100 - 1200°C to 1550 - 1580°C at a rate of 6 - 10°C / min, hold for 1 - 1.5 h, then heat to 1640 - 1650°C at a rate of 1 - 3°C / min, hold for 1.5 - 2 h, then cool to 1605 - 1610°C at a rate of 1 - 3°C / min, clarify and hold for 20 - 30 min, and then cool to 1600°C at a rate of 1 - 3°C / min.

6. The preparation method of a glass substrate according to claim 3, wherein, The forming, annealing, and cooling process is to pour the melted glass melt into a mold, place it at 730 - 750°C for annealing, and then cool to room temperature with the furnace.

7. The preparation method of a glass substrate according to claim 3, characterized in that, The thickness of the glass substrate is 0.2 - 1 mm, and the plate width is 2000 - 3000 mm.

8. A method for preparing a glass substrate according to claim 3, characterized in that, The glass raw materials include SiO2, Al2O3, B2O3, and alkaline earth metal oxides.

9. The preparation method of a glass substrate according to claim 8, wherein, The dosage ratio of SiO2, Al2O3, B2O3, and alkaline earth metal oxides is (56 - 65):(13 - 22):(0.05 - 12):(9 - 24).

10. The manufacturing method of a glass substrate according to claim 8, wherein, The alkaline earth metal oxides are one or a combination of CaO, MgO, BaO, and SrO.

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