Glass etching activating solution and method for preparing same, method for glass alkaline etching

Abstract

The application relates to the field of glass etching, and discloses a glass etching activation solution, a preparation method thereof and a glass alkali etching method. + , Li + , an amide compound; the H + is provided by an organic acid with a carbon content greater than or equal to 6; the molar concentration of the H + in the activation solution is 0.006-0.04 mol / L, the molar concentration of the Li + is 0.07-0.3 mol / L, and the mass content of the amide compound is 0.2-1 wt%. The glass etching activation solution provided by the application can improve the glass etching rate, inhibit the generation and expansion of micro cracks, and guarantee the mechanical properties and long-term reliability of the glass.

Description

Technical Field

[0001] This invention relates to the field of glass etching, specifically to a glass etching activating solution and its preparation method, and a method for glass alkaline etching. Background Technology

[0002] In the current glass etching field, hydrofluoric acid (HF) and sodium hydroxide (NaOH) alkaline systems remain the main process routes. However, with increasingly stringent environmental protection requirements, the application of HF acid systems is gradually being restricted due to their environmental and safety risks, leading many companies and factories to shift their research and development focus to alkaline etching systems.

[0003] Currently, the common alkaline etching conditions for glass mainly include the following three: ① 30wt% NaOH, 100℃; ② 50wt% NaOH, 120℃; ③ 70wt% NaOH, 170℃. The first two conditions have relatively low etching rates, making it difficult to meet the needs of high-efficiency production. Although the third condition can significantly improve the etching speed, the high concentration of alkaline solution and high temperature environment not only greatly increases the process cost and energy consumption, but also increases the risk of harm to operators. At the same time, it places higher demands on the corrosion resistance, stability, and maintenance of the reaction equipment.

[0004] To improve etching efficiency, the industry has attempted to pre-activate the glass with a strong acid solution before alkaline etching. However, this method easily introduces or propagates microcracks on the glass surface, leading to a decrease in the glass's mechanical strength and impact resistance, thus limiting its practical application.

[0005] Therefore, there is an urgent need to develop a new technology that can significantly improve the glass alkaline etching rate while effectively suppressing the generation and propagation of microcracks, thereby balancing process efficiency, material properties and production safety. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of low glass alkali etching efficiency in the prior art and the tendency of pre-activation treatment to improve efficiency to cause microcracks that damage the glass properties.

[0007] To achieve the above objectives, a first aspect of the present invention provides a glass etching activation solution containing H. + Li + Amide compounds; the H + Provided by organic acids with a carbon content of 6 or more; the H in the activation solution + The molar concentration of Li is 0.006-0.04 mol / L. + The molar concentration is 0.07-0.3 mol / L, and the mass content of amide compounds is 0.2-1 wt%.

[0008] A second aspect of the present invention provides a method for preparing the glass etching activating solution described in the first aspect, the method comprising: mixing water, lithium salt, organic acid with a carbon content of 6 or more, and amide compound.

[0009] A third aspect of the present invention provides a method for alkaline etching of glass, the method comprising: first activating the glass in a glass etching activation solution, and then etching it in an alkaline etching solution; wherein the glass etching activation solution is the glass etching activation solution described in the first aspect.

[0010] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects: (1) The glass etching activation solution provided by the present invention does not contain fluoride ions, which can greatly reduce the harm to operators and the environment, and is in line with the trend of green production; (2) The glass etching activation solution provided by the present invention can be used for activation treatment, which can greatly improve the glass etching rate under the same alkaline etching conditions and overcome the problem of low efficiency of traditional alkaline etching. (3) The glass alkaline etching method provided by the present invention can effectively remove by-products and other impurities attached to the surface during the etching process, while inhibiting the generation and propagation of microcracks, thereby ensuring the mechanical properties and long-term reliability of the glass. (4) The activation system provided by the present invention is mild (weakly acidic / low temperature), has low requirements for equipment and operation, and can be fully automated with subsequent processes. Attached Figure Description

[0011] Figure 1 This is a glass surface crack width diagram obtained by activating the glass surface with the glass etching activation solution obtained in Example 1 of the present invention and then performing alkaline etching. Figure 2 This is a glass surface crack width diagram obtained by activating the glass surface with the glass etching activation solution obtained in Comparative Example 2 of the present invention and then performing alkaline etching. Detailed Implementation

[0012] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0013] The "organic acid with a carbon content of 6 or more" mentioned in this invention refers to an organic acid with a total number of carbon atoms of not less than 6. For example, the organic acid with a carbon content of 6 or more can be an organic acid of C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, etc.

[0014] The "C6-C10 organic acid" mentioned in this invention refers to an organic acid with a total number of carbon atoms of 6-10. For example, the C6-C10 organic acid can be an organic acid of C6, an organic acid of C7, an organic acid of C8, an organic acid of C9, or an organic acid of C10.

[0015] The "C2-C6 amide compounds" mentioned in this invention refer to amide compounds with a total number of carbon atoms of 2-6. Exemplarily, the C2-C6 amide compounds can be C2 amide compounds, C3 amide compounds, C4 amide compounds, C5 amide compounds, and C6 amide compounds.

[0016] As previously described, a first aspect of the present invention provides a glass etching activation solution containing H. + Li + Amide compounds; the H + Provided by organic acids with a carbon content of 6 or more; H in the activation solution + The molar concentration of Li is 0.006-0.04 mol / L. + The molar concentration is 0.07-0.3 mol / L, and the mass content of amide compounds is 0.2-1 wt%.

[0017] This invention, through inventive research, discovered that by using organic acids with a carbon content of 6 or more, and Li... + By synergistically compounding with amide compounds and controlling their content within the range defined in this invention, H can be achieved. + The controlled release of H₂ utilizes the steric hindrance of the organic acid during the reaction to avoid excessively vigorous reaction per unit area, reducing local thermal stress caused by heat accumulation at the crack tip and thus inhibiting crack propagation. Simultaneously, under stable H₂... + Under certain concentration conditions, H + It can react with impurities (silicates, alkaline earth metal oxides, metal hydroxides) on the glass surface to generate substances soluble in the solution system, resulting in a more significant improvement in the efficiency of subsequent alkaline etching; in addition, this composite system can also utilize Li + Na at the crack tip +The exchange process forms a lithium silicate region with a smaller coefficient of thermal expansion, which in turn reduces the thermal expansion coefficient at the crack tip, alleviates the tendency of crack propagation induced by local thermal stress, and also affects H through the high electron cloud density of the amide compound's own conjugated system. + The binding energy synergistically stabilizes the local H + The concentration reduces the uneven stress distribution caused by differences in reaction heat in different regions, thereby achieving multiple inhibitions on microcrack propagation and ultimately achieving the goal of synergistic protection of efficient etching and glass structural integrity.

[0018] Preferably, the organic acid is a C6-C10 organic acid. In this preferred case, the organic acid will not completely ionize in aqueous solution, releasing H+. + The process is controllable and exhibits better H+ performance compared to inorganic strong acids. + Buffering effect; on the other hand, the organic acid has a suitable carbon chain structure, and during the reaction, it utilizes its own steric hindrance to ensure sufficient activation effect to improve the amount of subsequent alkaline etching, while better and more effectively inhibiting the propagation of microcracks, thus achieving the best balance between efficiency and product appearance quality.

[0019] Preferably, the H in the activation solution + The molar concentration is 0.01-0.04 mol / L. Under this preferred condition, the etching efficiency is higher, and the H2O is controlled. + Concentration can prevent violent reactions per unit area, reduce thermal stress caused by the heat of reaction at the crack tip, and thus slow down crack propagation.

[0020] Preferably, the Li + Provided by a water-soluble lithium salt. The lithium salt dissolves in the system and generates free Li. + Promote Li + The exchange of sodium ions with the crack tip is more conducive to slowing down the crack propagation caused by local thermal stress.

[0021] More preferably, the Li + It is provided by at least one selected from lithium nitrate, lithium chloride, and lithium citrate. In this preferred embodiment, lithium nitrate provides an oxidizing environment, improving the cleanliness and uniformity of the glass surface; lithium chloride enhances ion exchange, is highly efficient and low-cost; and lithium citrate has good buffering and complexing capabilities, accurately stabilizing the reaction interface and preventing impurity precipitation.

[0022] Preferably, the first ionization constant of the C6-C10 organic acid is greater than or equal to 1 × 10⁻⁶. -5 Under these preferred conditions, the target H can be achieved with the minimum necessary addition amount. + The concentration (0.006-0.04 mol / L) is controlled to prevent excessive accumulation of organic molecules on the glass surface and ensure unobstructed activation reaction interface.

[0023] Preferably, the C6-C10 organic acid is selected from at least one of mono- or poly-aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids. In this preferred embodiment, the flexible carbon chain structure of aliphatic acids optimizes the wettability and permeability of the activated surface, the rigid structure of alicyclic acids provides more stable interfacial adsorption, and aromatic acids, with their conjugated structure, provide strong metal ion complexation and cleaning capabilities, ensuring the cleanliness of the activated surface.

[0024] More preferably, the C6-C10 organic acid is selected from at least one of citric acid, hexanoic acid, adipic acid, heptanoic acid, pimelic acid, octanoic acid, octanoic acid, nonanoic acid, azelaic acid, decanoic acid, sebacic acid, gluconic acid, benzoic acid, phthalic acid, and phthalic acid. In this preferred embodiment, the organic acid has a moderate carbon chain length and good solubility balance in the activation system, which can effectively avoid surface contamination and etching barriers, ensuring process stability and repeatability in industrialized production.

[0025] Preferably, the first ionization constant of the C6-C10 organic acid is greater than 1 × 10⁻⁶. -4 In this preferred embodiment, the organic acid has a high degree of ionization and inherent buffering capacity, enabling it to neutralize H+ in the activation solution. + The concentration remains at a higher and dynamically stable level.

[0026] More preferably, the C6-C10 organic acid is citric acid. The unit mass H of citric acid... + It has a high content, is commonly used in industry, and is applied to this invention at a lower cost.

[0027] Preferably, the amide compound is a C2-C6 amide compound. Excessively long carbon chains in amide compounds can hinder the activation reaction of organic acids and Li. + Na at the crack tip + The exchange reaction reduces the activation effect; in this preferred case, the high electron cloud density of the O=CN conjugated system can be used to bind H. + Better synergistic stabilization of local H+ in organic acid carbon chains + The concentration makes the stress distribution more uniform, thereby achieving the best balance between etching efficiency and glass structural integrity.

[0028] Preferably, the C2-C6 amide compound is selected from at least one of acetamide, hexamethylenetetramine, N,N-dimethylacetamide, and N-isopropylacrylamide. In this preferred embodiment, the C2-C6 amide compound has a high electron cloud density in its conjugated system, resulting in stable local H+. + The concentration effect is better, and the cost is lower when applied to this invention.

[0029] Preferably, the H in the activation solution+ and Li + The molar concentration ratio is 0.04-0.20:1.

[0030] More preferably, the H in the activation solution + and Li + The molar concentration ratio is 0.09-0.20:1. In this preferred case, Li + Introducing a reduced coefficient of thermal expansion at the crack can mitigate the effects of H to the greatest extent possible. + The activation reaction generates thermal stress, which leads to crack propagation.

[0031] As previously stated, a second aspect of the present invention provides a method for preparing the glass etching activating solution described in the first aspect, the method comprising: mixing water, lithium salt, an organic acid with a carbon content of 6 or more, and an amide compound.

[0032] As mentioned above, a third aspect of the present invention provides a method for glass alkaline etching, the method comprising: first activating the glass in a glass etching activation solution, and then etching it in an alkaline etching solution; wherein the glass etching activation solution is the glass etching activation solution described in the first aspect.

[0033] Preferably, the activation treatment conditions include a temperature of 60-70°C and a time of 5-10 minutes. Under these preferred conditions, the activation solution can effectively act at a relatively mild temperature and time, which can fully activate the glass surface to ensure the efficiency and consistency of subsequent alkaline etching, while avoiding the risk of local thermal stress concentration and microcrack propagation caused by harsh reaction conditions. Thus, while achieving efficient etching, the structural integrity and mechanical properties of the glass are better maintained.

[0034] Preferably, the etching conditions include a temperature of 85-95℃ and a time of 5-15 minutes. In this preferred embodiment, the synergistic effect of the highly efficient surface pre-activation and crack inhibition of the activating solution provided by the present invention enables the alkaline etching process to achieve ideal etching efficiency without relying on traditional high temperatures. This not only significantly reduces the overall energy consumption and equipment requirements of the process but also avoids the thermal shock and stress damage to the glass structure caused by the harsh etching environment, further ensuring the mechanical properties of the glass and the product yield.

[0035] Preferably, the activated glass contains at least one alkali metal element, wherein the alkali metal element is at least one selected from sodium, potassium, and rubidium. In this preferred embodiment, the alkali metal element in the glass can react with Li in the activation solution. + A chemical displacement reaction occurs, enhancing the crack propagation inhibition effect brought about by the activation process.

[0036] To clean the glass surface activation solution and reduce fluctuations in the alkaline etching system, the glass alkaline etching method provided by the present invention preferably further includes: performing a first hot water bath after the activation treatment.

[0037] In order to clean and neutralize the residual alkali solution and prevent stains from forming after drying or affecting subsequent processing, the glass alkali etching method provided by the present invention preferably further includes a second hot water bath after etching.

[0038] This invention does not limit the conditions of the first and second hot water baths; those skilled in the art can choose according to actual needs. Exemplarily, the conditions for the first and second hot water baths independently include: a temperature of 80-100℃ and a time of 2-10 minutes.

[0039] It should be noted that the glass alkaline etching method provided by this invention also includes conventional pretreatment steps, such as cleaning and preheating the glass before activation treatment. These will not be elaborated upon here, and those skilled in the art should not construe them as limiting the invention.

[0040] It should also be noted that the glass alkaline etching method provided by this invention can selectively repeat the series of steps of "activation treatment - first hot water bath - etching - second hot water bath" according to the specific requirements of the etching removal amount, thereby flexibly controlling the etching depth and morphological accuracy to meet the actual production needs of diverse etching amounts and complex structure processing. The invention will not be described in detail here, and those skilled in the art should not construe it as a limitation of the invention.

[0041] In a preferred embodiment, the alkaline etching solution contains 10-50 wt% alkali metal hydroxide and the balance water. In this preferred embodiment, thanks to the synergistic effect of the activating solution's efficient surface pre-activation and crack inhibition, the alkaline etching process can achieve ideal etching efficiency without relying on traditional high-concentration etching systems. This not only significantly reduces the process's stringent requirements on alkali concentration and supporting equipment but also avoids thermal shock and structural stress caused by the violent reaction of strong alkalis from the outset, thereby better maintaining the mechanical integrity of the glass and the product yield while achieving efficient etching.

[0042] Preferably, the alkali metal is selected from at least one of Na, Li, K, and Rb.

[0043] More preferably, the alkali metal is Na. In this preferred embodiment, production costs are lower, and the unit mass provides a nucleophile (OH-). - There are many, the overall cost performance is high, and Na + With a small radius, it has a weaker hindrance to the etching process and achieves the best etching rate.

[0044] To further optimize the stability of the etching process and the quality of the glass surface, the alkaline etching solution preferably also contains a chelating agent.

[0045] Preferably, the chelating agent is selected from at least one of polyol amines, disodium EDTA, sodium gluconate, and sodium citrate. In this preferred embodiment, the chelating agent can form a stable chelate with the metal ions in the etched product, reducing the consumption of hydroxide ions by the metal ions and promptly removing surface-adhered impurity ions to ensure continuous etching.

[0046] This invention does not have specific requirements regarding the content of chelating agents in the alkaline etching solution; those skilled in the art can select them conventionally according to their needs. Further details of this invention are omitted here, and should not be construed as limiting the invention.

[0047] The invention will now be described in detail through implementation. Unless otherwise specified, all instruments and reagents used in the following examples are commercially available.

[0048] Preparation Example 1 This preparation example illustrates the mixing and preparation of the glass etching activation solution provided by the present invention according to the formula in Table 1: Unless otherwise specified, the remaining preparation examples and comparative preparation examples were carried out using a similar process to that of preparation example 1. The difference is that the formulations used in each example are different, as detailed in Table 1 (Note: all parameters not listed in Table 1 are the same as those in preparation example 1); in Table 1, each wt% represents 2g.

[0049] In Table 1, taking Preparation Example 1 as an example, the calculation formulas for each ion concentration are as follows: All raw materials were weighed according to the mass percentage range in Table 1, based on 200g of water, and dissolved (i.e., each wt% represents 2g), and the volume was measured with water to 200ml.

[0050] In Preparation Example 1, 20g of anhydrous citric acid, 2g of lithium nitrate, and 1g of acetamide were weighed into a reaction vessel, and water was added to a measured volume to 200 ml. The mixture was then thoroughly mixed. The molar amount of citric acid is: 20 (g) / 192.12 (g / mol) = 0.104 mol; The molar concentration of citric acid is: 0.104 mol / 0.2 mL = 0.52 mol / L; Free H + Concentration: Citric acid is a tribasic weak acid, and the free hydrogen ion concentration is mainly determined by the first-order dissociation. K a1 =C H +×C A - / C A C H+= C A -, C A =0.52, K a1 =7.4×10 -4 ; Therefore, free H + The concentration was 0.019 mol / L; Free Li + Concentration: c(Li) + ) = m (LiNO 3 ) / (M (LiNO 3 ) (×0.2) = 0.145 mol / L.

[0051] Table 1

[0052] Example 1 This embodiment illustrates the etching effect of alkaline etching after activation treatment with the glass etching activation solution obtained in the aforementioned preparation examples and comparative preparation examples. The specific steps are as follows: Preparation of alkaline etching solution: Take 120g of anhydrous sodium hydroxide and add it to 280g of pure water in small amounts several times. After stirring thoroughly, heat to 90℃ for later use. (1) Clean the glass with no visible cracks on the polished surface using ultrasonic cleaning in pure water; (2) Preheat the cleaned glass to 60°C with pure water; (3) Immerse the preheated glass in the activation solution for activation treatment; the activation conditions are: temperature 65℃, time 8min; (4) The activated glass is subjected to a first hot water bath (temperature 90℃, time 5min), and then etched in an alkaline etching solution; the etching conditions are: temperature 90℃, time 10min. (5) The etched glass is subjected to a second hot water bath (temperature 90℃, time 5min). (6) The glass after the second hot water bath is dried to obtain etched glass; This experimental process repeats steps (3) to (5) according to the etching removal requirements, for a total of four times; the etching results are shown in Table 2; The etching rate is obtained by testing the change in glass thickness: Etching rate = Change in thickness before and after etching / Time / 2, which is divided by 2 to express the etching rate of one side of the glass. Thickness testing instrument: Crystal thickness gauge; Testing principle: A high-resolution CCD camera and an automatic zoom objective lens are used to measure the position of the upper and lower surfaces of the product through a dual-probe optical system. The product thickness is calculated by the distance difference between the two optical probes.

[0053] In Table 2, cracks with a width of 10 μm or more are considered obvious cracks, cracks with a width of 5-10 μm are considered minor cracks, and cracks with a width of less than 5 μm are considered no cracks.

[0054] Table 2

[0055] As can be seen from the results in Table 2, activation with the glass etching activating solution provided by this invention can improve the etching efficiency of glass alkaline etching (etching rate above 13 μm / h / side), while inhibiting the generation and propagation of microcracks, thereby ensuring the mechanical properties and long-term reliability of the glass; specifically: A comparison of the examples with Comparative Example 1 shows that the activation system contains H. + It can significantly improve the subsequent alkaline etching rate; as can be seen from the comparison between Example 1 and Comparative Examples 2 and 5, the introduction of organic acid can realize the H in the activation solution + The controllable release of Li significantly improves the subsequent alkaline etching rate; a comparison between Example 1 and Comparative Examples 4, 7, and 8 shows that the introduction of Li + Amide compounds, in synergy with the steric hindrance of organic acids, reduce the thermal stress caused by the heat of reaction at the crack tip, thereby slowing crack propagation. Furthermore, the high electron cloud density of the conjugated system of amide compounds has a positive effect on H... + While creating binding, it also binds free Li in the activation solution. + This causes it to accumulate at the crack tip; therefore, when Li is introduced alone... + When amide compounds are added to the activation solution system, the prepared activation solution has a poor inhibitory effect on crack propagation; a comparison between the examples and comparative examples 3 and 6 shows that the carbon chain length of organic acids and the H provided by organic acids are important factors. + The concentration is outside the range specified in this invention. Although it improves etching efficiency, it has a poor effect on suppressing crack propagation.

[0056] The present invention also provides, by way of example, crack width diagrams of glass surfaces after activation treatment with the glass etching activation solution obtained in Example 1 and Comparative Example 2 followed by alkaline etching. Figure 1 and Figure 2 ); It should be noted that, in this invention, the crack width map after active etching of the glass surface is tested using a Zygo instrument.

[0057] like Figure 1 and Figure 2 As shown, where, Figure 1 This is a crack width diagram of the glass surface obtained by activated etching in Example 1. Figure 2The image shows the crack width of the glass surface obtained by activated etching in Comparative Example 2. It can be clearly seen from the image that the glass etching activation solution provided by the present invention can effectively inhibit the propagation of surface microcracks generated in the glass during the acid activation process.

[0058] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A glass etching activating solution, characterized in that, The activation solution contains H + Li + Amide compounds; the H + Provided by organic acids with a carbon content of 6 or more; H in the activation solution + The molar concentration of Li is 0.006-0.04 mol / L. + The molar concentration is 0.07-0.3 mol / L, and the mass content of amide compounds is 0.2-1 wt%.

2. The glass etching activating solution according to claim 1, characterized in that, The organic acid is a C6-C10 organic acid; And / or, the H in the activation solution + The molar concentration is 0.01-0.04 mol / L.

3. The glass etching activating solution according to claim 1, characterized in that, The Li + Provided by water-soluble lithium salts; And / or, the Li + It is provided by at least one selected from lithium nitrate, lithium chloride, and lithium citrate.

4. The glass etching activating solution according to claims 1-3, characterized in that, The first ionization constant of the C6-C10 organic acids is greater than or equal to 1 × 10⁻⁶. -5 ; And / or, the C6-C10 organic acid is selected from at least one of mono- or poly-aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids.

5. The glass etching activating solution according to claim 4, characterized in that, The first ionization constant of the C6-C10 organic acids is greater than 1 × 10⁻⁶. -4 .

6. The glass etching activating solution according to claims 1-3, characterized in that, The amide compounds are C2-C6 amide compounds.

7. The glass etching activating solution according to claims 1-3, characterized in that, H in the activation solution + and Li + The molar concentration ratio is 0.04-0.20:

1.

8. A method for preparing the glass etching activating solution according to any one of claims 1-7, characterized in that, The method includes mixing water, lithium salt, organic acid with a carbon content of 6 or more, and amide compound.

9. A method for glass alkaline etching, characterized in that, The method includes: first activating the glass in a glass etching activation solution, and then etching it in an alkaline etching solution; wherein the glass etching activation solution is the glass etching activation solution according to any one of claims 1-7.

10. The method according to claim 9, characterized in that, The activation treatment conditions include: a temperature of 60-70℃ and a time of 5-10 min; And / or, the etching conditions include: a temperature of 85-95°C and a time of 5-15 min; And / or, the alkaline etching solution contains 10-50 wt% alkali metal hydroxide and the balance water; And / or, the alkali metal is selected from at least one of Na, Li, K, and Rb.

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