An etching composition for repairing micro-cracks on an ultra-thin flexible glass surface and a method of preparing the same

Abstract

This invention discloses an etching composition and its preparation method for repairing microcracks on the surface of ultrathin flexible glass, belonging to the field of glass surface treatment technology. The etching composition includes hydrofluoric acid, sulfuric acid, acetic acid, myo-inositol hexaphosphate, 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, and the balance water. During preparation, 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, myo-inositol hexaphosphate, acetic acid, sulfuric acid, and hydrofluoric acid are sequentially mixed with water and filtered. This invention utilizes the synergistic effect of myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt to effectively repair microcracks on the surface of ultrathin flexible glass while reducing overall glass thinning and excessive etching of the intact surface, thus improving surface quality and bending reliability.

Description

Technical Field

[0001] This invention relates to the field of glass surface treatment technology, specifically to an etching composition for repairing microcracks on the surface of ultrathin flexible glass and its preparation method. Background Technology

[0002] With the development of foldable displays, flexible electronic devices, and ultra-thin display modules, ultra-thin flexible glass is increasingly being used for covering and protecting flexible display devices due to its superior optical properties, dimensional stability, heat resistance, and surface hardness. To meet the requirements of bending applications, ultra-thin flexible glass typically has a small thickness. However, as the glass thickness decreases, it becomes more sensitive to surface defects and microcracks. During cutting, grinding, handling, cleaning, and subsequent processing, scratches and microcracks are easily generated on the glass surface or edges. These defects can easily lead to stress concentration under bending or cyclic loading, and further propagate, thus affecting the mechanical strength and long-term reliability of the glass.

[0003] Currently, glass surfaces can be treated using chemical etching. By removing microcracks and some of the surrounding glass material, the crack tips are gradually blunted or the crack size is reduced, thereby improving the surface defect condition of the glass. Common glass etching systems typically use fluorinated etchants as the main active ingredient, combined with other acidic components to adjust the etching rate, surface condition, and processing.

[0004] However, for ultrathin flexible glass with relatively small thickness, the allowable amount of material removal is limited, and the morphology, depth, and distribution of microcracks vary. Existing etching systems may still encounter problems in actual processing, such as insufficient etching uniformity, difficulty in balancing microcrack repair with overall glass thinning, unnecessary etching of the intact surface, and fluctuations in surface quality after processing. When the etching degree is insufficient, some microcracks may not be adequately repaired; while excessive etching may lead to increased glass thickness loss, decreased surface quality, and affect the subsequent bending performance and reliability of the ultrathin flexible glass.

[0005] Therefore, there is still a need for further improvement in the existing etching systems for repairing microcracks on ultrathin flexible glass surfaces in terms of repair effect, material loss control, surface quality and processing stability. It is necessary to develop etching compositions and their preparation methods with better overall performance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an etching composition and its preparation method for repairing microcracks on the surface of ultrathin flexible glass. The etching composition of the present invention, through the synergistic effect of a basic acid system with myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, maintains the ability to etch and repair microcracks in ultrathin flexible glass while reducing excessive etching in defect-free areas and overall material loss, improving the transfer of reactants and products deep within the crack, and making the microcrack repair process more uniform and controllable. This, in turn, helps to maintain the glass thickness, surface quality, and subsequent flexible performance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: An etching composition for repairing microcracks on the surface of ultrathin flexible glass, comprising, by weight of effective ingredients and based on the total mass of the etching composition (100%), 2.0-8.0 wt% hydrofluoric acid, 4.0-12.0 wt% sulfuric acid, 3.0-12.0 wt% acetic acid, 0.03-0.60 wt% myo-inositol hexaphosphate, 0.01-0.30 wt% 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, and the balance being water.

[0008] Furthermore, the mass ratio of myo-inositol hexaphosphate to the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is 1:0.05 to 1:1.50.

[0009] In one embodiment, the myo-inositol hexaphosphate is added in the form of an aqueous solution of myo-inositol hexaphosphate. The method for preparing the aqueous solution of myo-inositol hexaphosphate includes: mixing phytate with water to obtain an aqueous phytate phase; and reacting the aqueous phytate phase with H₂O₂. + The first effluent is collected by contacting a strong acidic cation exchange resin; the first effluent is then concentrated for the first time, so that the concentrated first effluent reacts with OH-. - The solution is contacted with a weakly basic anion exchange resin, and the second effluent is collected. The second effluent is then concentrated a second time to obtain the myo-inositol hexaphosphate aqueous solution.

[0010] Furthermore, the phytate is selected from at least one of sodium phytate, potassium phytate, ammonium phytate, and calcium magnesium phytate; the mass ratio of the phytate to water is 1:10 to 1:30.

[0011] Furthermore, the H + The total exchange capacity of the strong acid cation exchange resin is 1.05 to 2.50 times the total equivalent of exchangeable cations in the phytate. The aqueous phase of the phytate and the H2O... +The contact temperature for the strong acid cation exchange resin is 10~35℃, and the contact time is 0.5~4h.

[0012] Furthermore, the OH - The total exchange capacity of the weakly basic anion exchange resin is 1.05 to 3.00 times the total equivalent of inorganic acid radicals in the first effluent. The concentrated first effluent reacts with the OH... - The contact temperature for the weakly basic anion exchange resin is 10~35℃, and the contact time is 0.5~4h.

[0013] Furthermore, both the first and second concentrations are carried out at a temperature not exceeding 50°C and an absolute pressure of 2-30 kPa, resulting in a myo-inositol hexaphosphate aqueous solution with a myo-inositol hexaphosphate mass fraction of 50-80 wt%.

[0014] In another embodiment, the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is prepared by the following method: N,N-dimethylethylamine is mixed with anhydrous organic solvent, and 1,3-propanesulfonyl lactone is added to carry out a ring-opening quaternization reaction to obtain a reaction solution; the reaction solution is cooled to precipitate the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt; the precipitated 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is sequentially filtered, washed, and dried.

[0015] Furthermore, the molar ratio of N,N-dimethylethylamine to 1,3-propanesulfonyl lactone is 1:0.95 to 1:1.05.

[0016] Furthermore, the anhydrous organic solvent is anhydrous acetonitrile or anhydrous acetone, and the volume ratio of the anhydrous organic solvent to the total mass of N,N-dimethylethylamine and 1,3-propanesulfonyl lactone is 5~25 mL / g.

[0017] Furthermore, the ring-opening quaternization reaction is carried out under inert gas protection and without the addition of a catalyst, at a reaction temperature of 30~60℃ and a reaction time of 12~48h.

[0018] Furthermore, the cooling temperature of the reaction solution is 0~10℃, and the cooling time is 1~6h; the washing uses anhydrous acetonitrile, anhydrous acetone or ethyl acetate, and the volume ratio of the washing solvent to the mass of the precipitated product is 2~10mL / g; the drying is carried out at 35~60℃ and an absolute pressure of 5~30kPa for 6~24h.

[0019] The present invention also provides a method for preparing the above-mentioned etching composition, comprising the following steps: S1. Add 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt to a portion of water and mix to obtain the first mixture; S2. Add myo-inositol hexaphosphate and acetic acid to the first mixture to obtain the second mixture; S3. Add sulfuric acid to the second mixture to obtain the third mixture; S4. Add hydrofluoric acid and the remaining water to the third mixture and mix to obtain a mixture; S5. Filter the mixture to obtain the etching composition.

[0020] Further, in step S1, the water portion accounts for 60-80% of the total mass of the formula water, and the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is added at 15-30°C and mixed for 10-30 minutes.

[0021] Further, in step S2, after adding the myo-inositol hexaphosphate, mix for 5-20 minutes, then add the acetic acid and mix for 5-20 minutes.

[0022] Furthermore, in step S3, the sulfuric acid is added within 10 to 60 minutes, and the material temperature is controlled to be no higher than 35°C.

[0023] Further, in step S4, the third mixture is cooled to 20~30°C, the hydrofluoric acid is added within 10~60 minutes while controlling the material temperature not to exceed 30°C, and the remaining water is added and mixing continues for 10~30 minutes.

[0024] Further, the hydrofluoric acid is added as an aqueous solution of hydrofluoric acid with a mass fraction of 35-45 wt%; the sulfuric acid is added as concentrated sulfuric acid with a mass fraction of 95-98 wt%; the acetic acid is added as glacial acetic acid with a mass fraction of not less than 99 wt%; the myo-inositol hexaphosphate is added as an aqueous solution of myo-inositol hexaphosphate with a mass fraction of 50-80 wt%; and the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is added as a solid with a purity of not less than 95 wt%.

[0025] Furthermore, in step S5, the filtration is carried out at 10~30℃, using a hydrofluoric acid resistant filter element with a pore size of 0.2~1.0μm, and the filter material of the hydrofluoric acid resistant filter element is polytetrafluoroethylene or polyvinylidene fluoride.

[0026] Compared with the prior art, the present invention has the following beneficial effects: This invention employs hydrofluoric acid, sulfuric acid, acetic acid, myo-inositol hexaphosphate, 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, and water to construct an etching composition for repairing microcracks on the surface of ultrathin flexible glass. Hydrofluoric acid is used to etch the glass network, sulfuric acid provides a suitable acidic environment, and acetic acid is used to regulate the wetting and reaction processes of the etching system. The introduction of myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt allows the etching process to no longer rely solely on the overall dissolution of the glass surface by the basic acid system. Instead, it enables synergistic regulation of the etching process and interfacial mass transfer process on the glass surface. This facilitates the repair of microcracks while reducing unnecessary etching in defect-free areas, minimizing overall glass thinning and localized over-etching, and improving the controllability of the microcrack repair process for ultrathin flexible glass.

[0027] The core of this invention lies in simultaneously introducing myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt into a basic etching system composed of hydrofluoric acid, sulfuric acid, and acetic acid. Myo-inositol hexaphosphate mainly alters the interfacial reaction state between the glass and the etching solution, thus limiting the continuous etching of the open surface; 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt further regulates the interfacial environment formed after the action of myo-inositol hexaphosphate, enabling the interface to maintain necessary mass transfer while retaining a certain barrier effect.

[0028] Myo-inositol hexaphosphate molecules contain multiple phosphate groups, which can react with Al 3+ Ca 2+ Mg 2+ Isovalent metal ions coordinate with each other. For aluminum-silicon ultrathin flexible glass, after hydrofluoric acid begins etching the glass, some aluminum, calcium, magnesium, and other elements in the glass surface can enter the liquid phase. Myo-inositol hexaphosphate reacts with these metal ions, which helps to form a region with a certain barrier effect at the interface between the glass and the etching solution. Because the open surface has sufficient contact with the etching solution, while the internal space of the microcrack is narrow and the material entry rate is relatively slow, the open surface can be affected by the above-mentioned interface effect earlier, which reduces the rate at which hydrofluoric acid continues to reach the open surface, while the hydrofluoric acid that has already entered the microcrack can continue to react with the glass near the crack wall and crack tip. Therefore, compared with the system that only uses a basic acid, the present invention is beneficial to improve the etching difference between the microcrack area and the open surface, thereby reducing the additional material loss of the defect-free surface while achieving the purpose of microcrack repair.

[0029] However, as the interaction between myo-inositol hexaphosphate and polyvalent metal ions continues, a strong interfacial barrier may gradually form near the microcrack inlet. If this region is too dense, it will not only reduce the rate at which hydrofluoric acid continues to penetrate deeper into the crack, but also hinder the outward diffusion of silicon- and aluminum-containing reaction products generated during etching within the crack. This will prematurely slow down etching in the deeper parts of the crack, resulting in reaction restriction before the crack tip is fully passivated. Therefore, while myo-inositol hexaphosphate alone can reduce the continuous etching of open surfaces, the new interfacial state it forms will also lead to the problem of impeded mass transfer within the crack.

[0030] To address the aforementioned issues, this invention further introduces 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt. This substance contains both quaternary ammonium cation groups and sulfonate anionic groups, exhibiting strong hydrophilicity. In an interfacial environment containing myo-inositol hexaphosphate, it helps maintain the presence of water molecules and the hydration state of the interfacial region, thereby reducing the obstruction to mass transfer caused by excessively dense packing in this region. Thus, the interfacial confinement effect of myo-inositol hexaphosphate is preserved, while the continued propagation of hydrofluoric acid into the microcrack and the migration of etching products from the crack interior to the exterior are not prematurely blocked.

[0031] Therefore, two synergistic effects are formed: myo-inositol hexaphosphate first utilizes the polyvalent metal ions generated during glass etching to regulate the interfacial reaction on the glass surface, reducing the continuous etching of open surfaces; after this effect increases the mass transfer resistance at the crack inlet, the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt further maintains the hydration and mass transfer conditions at the interface, allowing controlled etching to still occur inside the microcracks and the reaction products to be discharged. Through the above synergistic effect, the present invention is beneficial for balancing the etching suppression of open surfaces with the continuous repair of deep microcracks, reducing the overall material loss of ultrathin flexible glass under the same degree of microcrack repair, and reducing the risk of insufficient crack repair due to local mass transfer obstruction. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0033] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0034] The present invention will be further described below through specific embodiments.

[0035] Example 1

[0036] An etching composition for repairing microcracks on the surface of ultrathin flexible glass is prepared as follows.

[0037] (1) Preparation of myo-inositol hexaphosphate aqueous solution Weigh 50.00g of sodium phytate, add 1000.00g of deionized water, and stir at 25℃ until a homogeneous sodium phytate aqueous phase is formed.

[0038] Using H + A strong acidic cation exchange resin was used to perform ion exchange on the aqueous phase of sodium phytate. The H2O used... + The total exchange capacity of the strong acid cation exchange resin was configured to be 1.50 times the total equivalent of exchangeable cations in sodium phytate. The sodium phytate aqueous phase was then reacted with H₂O. + The strong acid cation exchange resin was contacted at 25°C for 2 hours to complete the ion exchange. After that, solid-liquid separation was performed, and the first effluent was collected.

[0039] The first effluent was concentrated under reduced pressure at 40℃ and 10 kPa. The total equivalent of inorganic acid anions in the concentrated first effluent was determined using OH- with a total exchange capacity of 1.50 times the measured total equivalent of inorganic acid anions. - The solution was treated with a weakly basic anion exchange resin and contacted at 25°C for 2 hours. After the exchange was completed, solid-liquid separation was performed, and the second effluent was collected.

[0040] The second effluent was concentrated under reduced pressure at 40°C and 10 kPa until the mass fraction of myo-inositol hexaphosphate was 65 wt%, yielding an aqueous solution of myo-inositol hexaphosphate for later use.

[0041] (2) Preparation of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt Weigh 7.31 g of N,N-dimethylethylamine and add it to 293 mL of anhydrous acetonitrile, stirring until well mixed; then add 12.21 g of 1,3-propanesulfonyl lactone. The molar ratio of N,N-dimethylethylamine to 1,3-propanesulfonyl lactone is 1:1.00, and the volume ratio of anhydrous acetonitrile to the total mass of N,N-dimethylethylamine and 1,3-propanesulfonyl lactone is approximately 15 mL / g.

[0042] Under nitrogen protection and without the addition of a catalyst, the resulting system was heated to 45°C and reacted for 24 h to allow N,N-dimethylethylamine to undergo a ring-opening quaternization reaction with 1,3-propanesulfonyl lactone.

[0043] After the reaction was completed, the reaction solution was cooled to 5°C and maintained for 4 hours to precipitate the inner salt of 3-(ethyldimethylammonium)propane-1-sulfonic acid. The precipitate was collected by filtration, washed with 120 mL of anhydrous acetone, and then the washed product was vacuum dried at 45°C and 15 kPa absolute pressure for 12 hours to obtain the inner salt of 3-(ethyldimethylammonium)propane-1-sulfonic acid for later use.

[0044] (3) Formulation of etching composition Weigh 100.00g of 40wt% hydrofluoric acid aqueous solution, 90.00g of 98wt% concentrated sulfuric acid, 60.30g of 99.5wt% glacial acetic acid, 3.08g of 65wt% myo-inositol hexaphosphate aqueous solution prepared in step (1), 1.00g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt prepared in step (2), and 745.62g of deionized water.

[0045] Take 521.93g of deionized water, add 1.00g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt at 25℃, and mix for 20min; add 3.08g of myo-inositol hexaphosphate aqueous solution, mix for 15min, then add 60.30g of glacial acetic acid and mix for 15min.

[0046] Under cooling conditions, add 90.00g of concentrated sulfuric acid within 35 minutes, controlling the material temperature to not exceed 35℃; then cool to 25℃, add 100.00g of hydrofluoric acid aqueous solution within 35 minutes, controlling the material temperature to not exceed 30℃; add the remaining 223.69g of deionized water, and continue mixing for 20 minutes.

[0047] The resulting mixture was filtered at 20°C using a polytetrafluoroethylene hydrofluoric acid resistant filter with a pore size of 0.6 μm to obtain 1000.00 g of etching composition.

[0048] The resulting etching composition, by weight of active ingredients, contains 4.00 wt% hydrofluoric acid, 8.82 wt% sulfuric acid, approximately 6.00 wt% acetic acid, approximately 0.20 wt% myo-inositol hexaphosphate, and 0.10 wt% 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, with a mass ratio of approximately 1:0.50 between myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt.

[0049] Example 2

[0050] An etching composition for repairing microcracks on the surface of ultrathin flexible glass is prepared as follows.

[0051] (1) Preparation of myo-inositol hexaphosphate aqueous solution: Prepare a myo-inositol hexaphosphate aqueous solution with a mass fraction of 65 wt% according to the method of step (1) in Example 1.

[0052] (2) Preparation of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt: 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt was prepared according to the method of step (2) in Example 1.

[0053] (3) Preparation of etching composition: Weigh 100.00g of 40wt% hydrofluoric acid aqueous solution, 90.00g of 98wt% concentrated sulfuric acid, 60.30g of 99.5wt% glacial acetic acid, 1.23g of 65wt% myo-inositol hexaphosphate aqueous solution obtained in step (1), 0.40g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt obtained in step (2) and 748.07g deionized water.

[0054] Take 523.65g of deionized water, add 0.40g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt at 25℃ and mix for 20min; add 1.23g of myo-inositol hexaphosphate aqueous solution and mix for 15min, then add 60.30g of glacial acetic acid and mix for 15min. Under cooling conditions, add 90.00g of concentrated sulfuric acid over 35min, controlling the material temperature not to exceed 35℃; after cooling to 25℃, add 100.00g of hydrofluoric acid aqueous solution over 35min, controlling the material temperature not to exceed 30℃; add the remaining 224.42g of deionized water and continue mixing for 20min.

[0055] The etching composition was obtained by filtration at 20°C using a polytetrafluoroethylene hydrofluoric acid resistant filter element with a pore size of 0.6 μm.

[0056] The resulting etching composition, by weight of active ingredients, contains 4.00 wt% hydrofluoric acid, 8.82 wt% sulfuric acid, approximately 6.00 wt% acetic acid, approximately 0.08 wt% myo-inositol hexaphosphate, and 0.04 wt% 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, with a mass ratio of approximately 1:0.50 between myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt.

[0057] Example 3

[0058] An etching composition for repairing microcracks on the surface of ultrathin flexible glass is prepared as follows.

[0059] (1) Preparation of myo-inositol hexaphosphate aqueous solution: Prepare a myo-inositol hexaphosphate aqueous solution with a mass fraction of 65 wt% according to the method of step (1) in Example 1.

[0060] (2) Preparation of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt: 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt was prepared according to the method of step (2) in Example 1.

[0061] (3) Preparation of etching composition: Weigh 100.00g of 40wt% hydrofluoric acid aqueous solution, 90.00g of 98wt% concentrated sulfuric acid, 60.30g of 99.5wt% glacial acetic acid, 4.62g of 65wt% myo-inositol hexaphosphate aqueous solution obtained in step (1), 1.50g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt obtained in step (2) and 743.58g deionized water.

[0062] Take 520.51g of deionized water, add 1.50g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt at 25℃ and mix for 20min; add 4.62g of myo-inositol hexaphosphate aqueous solution and mix for 15min, then add 60.30g of glacial acetic acid and mix for 15min. Under cooling conditions, add 90.00g of concentrated sulfuric acid over 35min, controlling the material temperature not to exceed 35℃; after cooling to 25℃, add 100.00g of hydrofluoric acid aqueous solution over 35min, controlling the material temperature not to exceed 30℃; add the remaining 223.07g of deionized water and continue mixing for 20min.

[0063] The etching composition was obtained by filtration at 20°C using a polytetrafluoroethylene hydrofluoric acid resistant filter element with a pore size of 0.6 μm.

[0064] The resulting etching composition, by weight of active ingredients, contains 4.00 wt% hydrofluoric acid, 8.82 wt% sulfuric acid, approximately 6.00 wt% acetic acid, approximately 0.30 wt% myo-inositol hexaphosphate, and 0.15 wt% 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, with a mass ratio of approximately 1:0.50 between myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is that sodium phytate is not subjected to H2O during the preparation of the first core component. + The solution is treated with a strong acidic cation exchange resin, and myo-inositol hexaphosphate is replaced with sodium phytate that has not undergone cation exchange.

[0067] (1) Preparation of sodium phytate aqueous solution: Weigh 50.00 g of sodium phytate, add 1000.00 g of deionized water, and stir at 25 °C until a homogeneous sodium phytate aqueous phase is formed. (H+ is not used.) +The sodium phytate aqueous phase was treated with a strong acid cation exchange resin, and then concentrated under reduced pressure at 40°C and 10 kPa to obtain a sodium phytate aqueous solution with a mass fraction of 65 wt%, which was then set aside for later use.

[0068] (2) 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt was prepared according to the method of step (2) in Example 1.

[0069] (3) Preparation of etching composition: Weigh 100.00g of hydrofluoric acid aqueous solution with a mass fraction of 40wt%, 90.00g of concentrated sulfuric acid with a mass fraction of 98wt%, 60.30g of glacial acetic acid with a mass fraction of 99.5wt%, 3.08g of sodium phytate aqueous solution with a mass fraction of 65wt% obtained in step (1), 1.00g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt and 745.62g of deionized water.

[0070] The mixture was mixed, acidified, and filtered according to the addition order and process conditions of step (3) in Example 1 to obtain 1000.00g of etching composition.

[0071] In this comparative example, the sample without H... + Sodium phytate treated with a strong acid cation exchange resin was used to replace myo-inositol hexaphosphate in Example 1, and the remaining components and preparation conditions were the same as in Example 1.

[0072] Comparative Example 2

[0073] The difference between this comparative example and Example 1 is that myo-inositol hexaphosphate is replaced with an effective mass of phosphoric acid.

[0074] 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt was prepared according to the method of step (2) in Example 1.

[0075] Weigh out 100.00 g of a 40 wt% hydrofluoric acid aqueous solution, 90.00 g of a 98 wt% concentrated sulfuric acid solution, 60.30 g of a 99.5 wt% glacial acetic acid solution, 2.35 g of an 85 wt% phosphoric acid aqueous solution, 1.00 g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, and 746.35 g of deionized water. The effective mass of phosphoric acid in the added phosphoric acid aqueous solution is approximately 2.00 g, which is essentially the same as the effective mass of myo-inositol hexaphosphate in Example 1.

[0076] The etch composition was prepared according to the order of addition and process conditions of step (3) in Example 1, wherein the aqueous phosphoric acid solution was added at the same position as the myo-inositol hexaphosphate aqueous solution in Example 1, and finally filtered under the same conditions to obtain 1000.00g of etch composition.

[0077] This comparative example is used to compare the differences between ordinary small molecule phosphate with phosphate groups and myo-inositol hexaphosphate with multiple phosphate groups.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 1 is that citric acid or other effective substances are used to replace myo-inositol hexaphosphate.

[0080] 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt was prepared according to the method of step (2) in Example 1.

[0081] Weigh out 100.00g of 40wt% hydrofluoric acid aqueous solution, 90.00g of 98wt% concentrated sulfuric acid, 60.30g of 99.5wt% glacial acetic acid, 2.00g of citric acid, 1.00g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt, and 746.70g of deionized water.

[0082] During preparation, 1.00g of 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt was added to a portion of deionized water and mixed. Then, 2.00g of citric acid was added. Subsequently, glacial acetic acid, concentrated sulfuric acid, hydrofluoric acid aqueous solution and the remaining deionized water were added in the order of step (3) of Example 1. The mixture was then treated with the same temperature, mixing time and filtration conditions as in Example 1 to obtain 1000.00g of etching composition.

[0083] In this comparative example, the added citric acid mass is essentially the same as the effective mass of myo-inositol hexaphosphate in Example 1, used to compare the differences between conventional multidentate metal ion chelators and myo-inositol hexaphosphate.

[0084] Comparative Example 4

[0085] The difference between this comparative example and Example 1 is that betaine is used to replace the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt by mass.

[0086] (1) The myo-inositol hexaphosphate aqueous solution was prepared according to the method of step (1) in Example 1, and the mass fraction of the obtained myo-inositol hexaphosphate aqueous solution was 65 wt%.

[0087] (2) Preparation of etching composition: Weigh 100.00g of 40wt% hydrofluoric acid aqueous solution, 90.00g of 98wt% concentrated sulfuric acid, 60.30g of 99.5wt% glacial acetic acid, 3.08g of 65wt% myo-inositol hexaphosphate aqueous solution, 1.00g betaine and 745.62g deionized water.

[0088] Take 521.93g of deionized water, add 1.00g of betaine at 25°C and mix for 20 min; add 3.08g of myo-inositol hexaphosphate aqueous solution and mix for 15 min, then add 60.30g of glacial acetic acid and mix for 15 min. Subsequently, under the same conditions as in Example 1, add concentrated sulfuric acid and hydrofluoric acid aqueous solution sequentially, add the remaining 223.69g of deionized water and continue mixing for 20 min.

[0089] The resulting mixture was filtered at 20°C using a polytetrafluoroethylene hydrofluoric acid resistant filter element with a pore size of 0.6 μm to obtain 1000.00 g of etching composition.

[0090] This comparative example uses small-molecule zwitterionic betaine with the same quaternary ammonium positive charge center and anionic group to replace the inner salt of 3-(ethyldimethylammonium)propane-1-sulfonic acid, in order to compare the differences in the role of different zwitterionic structures in this system.

[0091] I. Sample Preparation The same batch of aluminum-silicon ultrathin flexible glass with the same strengthening state and a thickness of 70μm was selected and cut into glass specimens of 50mm×20mm.

[0092] Using a calibrated diamond scribing needle of the same specification, a 10 mm long linear artificial surface microcrack was prepared in the center of the main surface of each glass specimen, with the scribing direction perpendicular to the length of the specimen. The scribing load was 0.25 N, and the scribing speed was 2 mm / s.

[0093] The surface opening defect depth of artificial microcracks was measured using a three-dimensional laser confocal microscope. A local reference plane was obtained by fitting the undamaged glass surfaces on both sides of the defect, and the vertical distance of the lowest resolvable position of the defect relative to this reference plane was determined as the surface opening defect depth D. Five locations were selected at equal intervals along the length of each artificial microcrack for measurement, and the average value was taken.

[0094] Samples with surface opening defects depths of 4.8–5.2 μm before screening were subjected to further testing.

[0095] The glass specimens were treated with the etching compositions prepared in Examples 1-3 and Comparative Examples 1-4, respectively. In the fixed-time test, each glass specimen was completely immersed in 200 mL of fresh etching composition at a temperature of 30°C for 30 seconds, with the same low-speed reciprocating motion performed during the treatment. After treatment, the specimens were immediately removed, rinsed with deionized water for 60 seconds, and dried with clean nitrogen.

[0096] For fixed-time tests used to measure surface defects, thickness, and surface roughness, 10 parallel specimens are used in each group; for quasi-static bending tests, 15 specimens are used in each group; and for cyclic bending tests, an additional 15 specimens are used in each group. The glass source, initial thickness, artificial defect preparation method, etching solution temperature, processing time, and cleaning and drying conditions are kept consistent across all groups.

[0097] II. Testing Methods 1. Surface defect reduction effect test The depth of surface opening defects on the same specimen before and after etching was determined using a three-dimensional laser confocal microscope, following the method described in the specimen preparation section.

[0098] The surface defect reduction rate is calculated according to the following formula: Surface defect reduction rate = (D0-D1) / D0×100%.

[0099] In the formula, D0 is the depth of the surface opening defect before treatment, and D1 is the depth of the residual surface opening defect after treatment.

[0100] A higher surface defect reduction rate and a smaller residual surface opening defect depth indicate a higher degree of geometric repair of artificial surface microcracks.

[0101] 2. Tests on overall glass thinning amount and thinning uniformity The thickness of the glass before and after etching was determined using a non-contact optical thickness gauge.

[0102] On each sample, avoid artificial defect areas, set 25 fixed measurement points in a 5×5 array, and ensure that the measurement positions before and after treatment correspond one-to-one.

[0103] The thickness difference before and after treatment at each measurement point is taken as the thinning amount at that point, and the average value of the 25 measurement points is taken as the average thinning amount of the sample.

[0104] The relative standard deviation (RSD) of the thinning amount at 25 measurement points for each sample was calculated, and the average value of the RSD of each group of samples was used to characterize the uniformity of thinning.

[0105] The defect reduction-thinning efficiency coefficient K is further calculated according to the following formula: K=(D0-D1) / ΔT.

[0106] In the formula, ΔT represents the average reduction in glass thickness.

[0107] A larger K value indicates a greater reduction in surface defect depth per unit thickness loss of the glass. This parameter is a macroscopic engineering evaluation index and is not equivalent to the ratio of local etching rates between cracked areas and intact surfaces.

[0108] 3. Surface roughness test The arithmetic mean height Sa of the surface was measured using a white light interferometer on the intact surface region of the glass specimen, away from artificial defects.

[0109] Five 1mm×1mm measurement areas were selected for each sample, and the average value was taken for each area.

[0110] The closer the processed Sa is to the unprocessed Sa, the lower the roughness of the intact surface during the etching repair process.

[0111] 4. Material loss test under equal repair levels Another batch of glass specimens with artificial surface microcracks prepared using the same method were treated with the etching compositions of Examples 1-3 and Comparative Examples 1-4, respectively.

[0112] The etching temperature was maintained at 30℃, and different etching times were set at 5-second intervals. New parallel test pieces were used at each time point. The same test piece was not repeatedly etched, cleaned, and then etched again.

[0113] Five samples were used for each candidate time point. The average residual surface opening defect depth after treatment at that time point was no more than 0.50 μm was taken as the unified repair endpoint. The shortest etching time required to reach this endpoint was determined, and the average thinning amount of the corresponding sample was measured.

[0114] 5. Quasi-static bending performance test The quasi-static bending performance of the repaired glass was tested using a U-shaped two-point bending method.

[0115] During the test, the side with the artificial surface microcracks was placed on the outside of the bend, i.e. under tension, and the direction of the artificial scratches was perpendicular to the direction of the maximum tensile stress.

[0116] The test environment was maintained at 23±2℃ and 50±5% relative humidity. The distance between the two parallel clamping ends was gradually reduced at a constant speed until the glass broke.

[0117] The glass bending profile was recorded using a side-view imaging method. The maximum curvature region in the middle of the specimen in the last complete image before fracture was fitted with a circular arc to obtain the minimum curvature radius R_f before failure.

[0118] Based on the actual thickness t_f of each sample after treatment, the bending strain ε_f of the failure surface is calculated according to the following formula: ε_f = t_f / (2R_f) × 100%.

[0119] The larger the value of ε_f, the greater the bending deformation that the glass can withstand after repair.

[0120] 6. Cyclic bending performance test Another 15 independent samples after being etched for 30 seconds were subjected to cyclic U-shaped bending tests.

[0121] The artificial surface microcracks are located on the outside of the bend. The curvature is adjusted according to the actual thickness of each sample after treatment, so that the maximum surface bending strain in the middle of the sample is 0.45%.

[0122] The cycle frequency is 0.5 Hz and the number of cycles is 10,000.

[0123] Record the number of specimens that did not break after 10,000 cycles, and calculate the cyclic bending pass rate according to the following formula: Cyclic bending pass rate = number of samples that did not break after 10,000 cycles / 15 × 100%.

[0124] III. Test Results Table 1. Surface defect reduction and glass thinning test results

[0125] Table 2. Surface roughness test results of the complete surface area

[0126] Table 3 Material loss when the same surface defect repair endpoint is reached.

[0127] Table 4. Bending performance of the repaired glass

[0128] As shown in Tables 1-4, Examples 1-3 exhibited good overall performance in terms of surface defect reduction rate, overall glass thinning, surface roughness, and bending reliability. Specifically, Example 1 achieved a surface defect reduction rate of 91.5%, an average thinning of only 1.31 μm, a post-treatment Sa of 10.6 nm, a bending strain of 0.69% on the failed surface, and a cyclic bending pass rate of 93.3%. This demonstrates that the composition of the present invention can effectively repair surface microcracks while reducing material loss in the intact glass area and maintaining good surface quality and flexible reliability.

[0129] Examples 2 and 3 show that the same overall performance trend was maintained even after changing the content of the two core components, indicating that myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt can stably exert a synergistic effect within the scope defined by this invention.

[0130] Comparative Example 1 uses untreated H +After treatment with a strong acidic cation exchange resin, the surface defect reduction rate of sodium phytate decreased to 84.5%, the average thinning amount increased to 1.58 μm, the Sa increased to 14.8 nm, and the bending performance also decreased significantly. This indicates that when the core component cannot exist in the form of myo-inositol hexaphosphate used in this invention, it is difficult to obtain the comprehensive performance of Example 1 even if the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is retained.

[0131] In Comparative Example 2, after replacing myo-inositol hexaphosphate with phosphoric acid, the surface defect reduction rate still reached 89.1%, but the average thinning amount increased to 2.69 μm, and the treated Sa reached 28.4 nm. This indicates that although the ordinary phosphoric acid system can reduce surface defects, it cannot effectively control the synchronous etching of the intact glass area. Therefore, this demonstrates that the myo-inositol hexaphosphate of this invention does not merely function as a common phosphoric acid-containing component.

[0132] In Comparative Example 3, replacing myo-inositol hexaphosphate with a conventional small-molecule complexing component resulted in a decrease in defect reduction rate, while the average thinning amount and surface roughness significantly increased, leading to a decline in bending reliability. This indicates that general metal ion complexation cannot replace the synergistic effect formed between myo-inositol hexaphosphate and the inner salt of 3-(ethyldimethylammonium)propane-1-sulfonic acid.

[0133] Comparative Example 4 retained myo-inositol hexaphosphate, replacing the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt with betaine. Its average thinning was 1.22 μm, and the treated Sa was 12.3 nm, indicating that material loss on the intact surface was still somewhat limited; however, the surface defect reduction rate was only 76.5%, and it took 60 s to reach the same repair endpoint, significantly lower than the repair efficiency of Example 1. These results indicate that myo-inositol hexaphosphate can provide good protection for the intact surface, but only when combined with the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt can sufficient microcrack repair be maintained simultaneously.

[0134] Comparative Example 2 mainly shows that "defects can be reduced relatively quickly, but overall thinning and surface roughening are severe"; while Comparative Example 4 shows that "overall thinning is controlled, but defect repair is insufficient". The two examples reveal opposite performance imbalances.

[0135] In contrast, Examples 1-3 simultaneously maintain a high defect reduction rate, a low overall thinning amount, and a good surface quality, and further achieve superior bending reliability. This demonstrates that myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt do not simply have a superimposed effect, but rather each performs a mutually reinforcing and interdependent function, jointly achieving a balance between intact glass area protection and continuous microcrack repair, resulting in a synergistic effect of the two components.

[0136] In summary, the overall performance of Examples 1-3 is significantly superior to that of the alternative comparative examples. Changing the first or second core component in each comparative example resulted in a significant decrease in at least one of the following: defect repair, material retention, surface quality, or bending reliability. This indicates that the coexistence of myo-inositol hexaphosphate and 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt can form a synergistic effect, enabling the present invention to simultaneously achieve more adequate microcrack repair and lower glass material loss.

[0137] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An etching composition for repairing microcracks on the surface of ultrathin flexible glass, characterized in that, Based on the total mass of the etching composition (100%), and by mass of the active ingredient, the etching composition comprises: 2.0~8.0 wt% hydrofluoric acid; 4.0~12.0 wt% sulfuric acid; 3.0~12.0 wt% acetic acid; 0.03~0.60 wt% myo-inositol hexaphosphate; 0.01~0.30 wt% 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt; and the balance being water.

2. The etching composition according to claim 1, characterized in that, The mass ratio of myo-inositol hexaphosphate to the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is 1:0.05 to 1:1.

50.

3. The etching composition according to claim 1, characterized in that, The myo-inositol hexaphosphate is added in the form of an aqueous solution of myo-inositol hexaphosphate, which is prepared by the following method: mixing phytate with water to obtain an aqueous phytate phase; reacting the aqueous phytate phase with H... + The first effluent is collected by contacting a strong acidic cation exchange resin; the first effluent is then concentrated for the first time, so that the concentrated first effluent reacts with OH-. - The solution is contacted with a weakly basic anion exchange resin, and the second effluent is collected. The second effluent is then concentrated a second time to obtain the myo-inositol hexaphosphate aqueous solution.

4. The etching composition according to claim 3, characterized in that, The phytate is selected from at least one of sodium phytate, potassium phytate, ammonium phytate, and calcium magnesium phytate; the mass ratio of the phytate to water is 1:10 to 1:30; the H + The total exchange capacity of the strong acid cation exchange resin is 1.05 to 2.50 times the total equivalent of exchangeable cations in the phytate. The aqueous phase of the phytate and the H2O... + The contact temperature of the strong acid cation exchange resin is 10~35℃, and the contact time is 0.5~4h; the OH... - The total exchange capacity of the weakly basic anion exchange resin is 1.05 to 3.00 times the total equivalent of inorganic acid radicals in the first effluent. The concentrated first effluent reacts with the OH... - The contact temperature of the weakly basic anion exchange resin is 10~35℃ and the contact time is 0.5~4h; the first concentration and the second concentration are carried out at a temperature not higher than 50℃ and an absolute pressure of 2~30kPa, and the mass fraction of myo-inositol hexaphosphate in the myo-inositol hexaphosphate aqueous solution is 50~80wt%.

5. The etching composition according to claim 1, characterized in that, The 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is prepared by the following method: N,N-dimethylethylamine was mixed with anhydrous organic solvent, and 1,3-propanesulfonyl lactone was added to carry out a ring-opening quaternization reaction to obtain a reaction solution. The reaction solution was cooled to precipitate the inner salt of 3-(ethyldimethylammonium)propane-1-sulfonic acid. The precipitated inner salt of 3-(ethyldimethylammonium)propane-1-sulfonic acid was filtered, washed and dried in sequence.

6. The etching composition according to claim 5, characterized in that, The molar ratio of N,N-dimethylethylamine to 1,3-propanesulfonyl lactone is 1:0.95 to 1:1.05; the anhydrous organic solvent is anhydrous acetonitrile or anhydrous acetone, and the volume ratio of the anhydrous organic solvent to the total mass of N,N-dimethylethylamine and 1,3-propanesulfonyl lactone is 5 to 25 mL / g; the ring-opening quaternization reaction is carried out under inert gas protection without the addition of a catalyst, at a reaction temperature of 30 to 60 °C and a reaction time of 12 to 48 h; the cooling temperature is 0 to 10 °C and the time is 1 to 6 h; the washing is performed using anhydrous acetonitrile, anhydrous acetone, or ethyl acetate, and the volume ratio of the washing solvent to the mass of the precipitated product is 2 to 10 mL / g; the drying is carried out at 35 to 60 °C and an absolute pressure of 5 to 30 kPa for 6 to 24 h.

7. A method for preparing the etching composition according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Add 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt to a portion of water and mix to obtain the first mixture; S2. Add myo-inositol hexaphosphate and acetic acid to the first mixture to obtain the second mixture; S3. Add sulfuric acid to the second mixture to obtain the third mixture; S4. Add hydrofluoric acid and the remaining water to the third mixture and mix to obtain a mixture; S5. Filter the mixture to obtain the etching composition.

8. The preparation method according to claim 7, characterized in that, In step S1, the water constitutes 60-80% of the total mass of the formulated water. The 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is added at 15-30°C and mixed for 10-30 minutes. In step S2, myo-inositol hexaphosphate is added and mixed for 5-20 minutes, followed by the addition of acetic acid and mixing for another 5-20 minutes. In step S3, sulfuric acid is added within 10-60 minutes, while controlling the material temperature to not exceed 35°C. In step S4, the third mixture is cooled to 20-30°C, and hydrofluoric acid is added within 10-60 minutes, while controlling the material temperature to not exceed 30°C. The remaining water is then added, and mixing continues for 10-30 minutes.

9. The preparation method according to claim 7, characterized in that, The hydrofluoric acid is added as an aqueous solution of hydrofluoric acid with a mass fraction of 35-45 wt%, the sulfuric acid is added as concentrated sulfuric acid with a mass fraction of 95-98 wt%, the acetic acid is added as glacial acetic acid with a mass fraction of not less than 99 wt%, the myo-inositol hexaphosphate is added as an aqueous solution of myo-inositol hexaphosphate with a mass fraction of 50-80 wt%, and the 3-(ethyldimethylammonium)propane-1-sulfonic acid inner salt is added as a solid with a purity of not less than 95 wt%.

10. The preparation method according to claim 7, characterized in that, In step S5, the filtration is carried out at 10~30℃, using a hydrofluoric acid resistant filter element with a pore size of 0.2~1.0μm, and the filter material of the hydrofluoric acid resistant filter element is polytetrafluoroethylene or polyvinylidene fluoride.

Images