Blackening liquid as well as preparation method and application thereof

Abstract

The invention relates to the technical field of preparation of blackening liquid, in particular to blackening liquid as well as a preparation method and application thereof, and the preparation method comprises the following steps: S1, adding thiourea and auxiliary alkali liquor into deionized water, slowly heating to 40 DEG C while stirring, and preserving heat; s2, continuously heating the solution in the step S1, keeping the temperature, continuously stirring until the solid is dissolved, adding a blackening modifier, and stirring; and S3, adding deionized water into the mixed solution obtained in the step S2, stirring, aging in a constant-temperature box, and carrying out pressure filtration through a microfiltration membrane to obtain the blackening solution. Through the synergistic effect of the corrosion inhibition modifier and the blackening modifier, the dispersion uniformity of the blackening liquid is improved, a compact and halo-free blackening layer and a hydrophobic film are formed on the copper surface, the leveling property of the blackening liquid is enhanced, corrosion medium permeation is blocked, and uneven blackening of the edge of a copper grid with the line width of 2-5 microns is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of blackening liquid, in particular to a blackening liquid, a preparation method and application thereof. Background Art

[0002] Metal-mesh film, the core material of transparent conductive film, achieves its conductivity through an ultra-fine metal mesh (typically copper). Using this ultra-fine metal mesh as the conductive functional layer, it achieves transparent conductivity. Touch sensors made with this film offer low power consumption, high touch sensitivity, and long service life. Furthermore, it is flexible, bendable, waterproof, explosion-proof, and pollution-free, making it widely used in touch screens. However, the copper mesh line width is only 2-5μm, below the human eye's threshold, but its strong reflectivity can still create visible halos under bright sunlight, affecting display quality and user experience. Traditional blackening solutions often contain phosphorus compounds (such as phosphates), the discharge of which can cause eutrophication (e.g., red tides) in water bodies. With strict phosphorus emission limits in Europe, the United States, Japan, and other regions (e.g., Germany requires ≤1mg / L), phosphate-free solutions are becoming an inevitable industry trend. Therefore, there is an urgent need to develop a phosphorus-free, low-temperature, high-efficiency, and copper-mesh-safe blackening solution that meets environmental requirements while achieving a balance between low reflectivity (shadow removal) and conductive properties on the copper surface. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the present invention aims to provide a blackening liquid, a preparation method and application thereof.

[0004] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a blackening liquid comprises the following steps: S1. By mass, 2-4 parts of thiourea 0.1-0.3 parts of auxiliary alkali solution are added to 45-50 parts of deionized water, stirred at a speed of 200-250r / min, and slowly heated to 40 ° C and kept warm for 10-15min; S2. The solution of step S1 is heated to 49-51 ° C, and the temperature is maintained and stirred for 30-35 min until the solid is dissolved, and then 1-1.7 parts of the blackening modifier is added and stirred at a speed of 100-200 r / min for 5-10 min; S3. To the mixture obtained in step S2, 45-50 parts of deionized water was added, stirred at a speed of 150-200r / min for 20-30min, aged in an incubator for 10-12h, and then pressure filtered through a microporous membrane to obtain a black liquid; The preparation of the blackening modifier comprises the following steps: S21. In a 45℃ constant temperature water bath, 9-11 parts of fatty alcohol polyoxyethylene ether is mixed with 1.5-2.5 parts of sodium dodecyl benzene sulfonate, stirred at 150-200r / min for 10-15min to obtain a transparent solution; S22. The water bath temperature is lowered to 40℃, 2-5 parts of corrosion inhibitor modifier is added, and stirred at 100-150r / min for 15-20min; S23. 0.1-0.2 parts of polydimethylsiloxane is added to the solution obtained in step S22, and after standing for 5-10min, it is dispersed at 200-250r / min for 2-4min to obtain a blackening modifier.

[0005] Preferably, the preparation of the corrosion inhibitor modifier comprises the following steps: S221. In a 40℃ water bath environment, 2-4 parts of catechol and 0.3-0.5 parts of mercaptobenzothiazole are added to 15-20 parts of ethanol solution, stirred at 200-250r / min for 15-20min to obtain an organic phase solution; S222. The water bath temperature is raised to 50℃, 0.8-1.2 parts of trisodium phosphate and 0.5-0.8 parts of sodium benzoate are added to 5-10 parts of ethanol solution, stirred at 250-300r / min for 10-15min to obtain an inorganic phase solution; S223. The organic phase solution and the inorganic phase solution are mixed and stirred at 150-200r / min for 20-25min, and then aged in the dark to obtain the corrosion inhibitor modifier.

[0006] Preferably, the auxiliary lye is composed of potassium carbonate, triethanolamine and borax in a mass ratio of 1:0.5-0.8:0.3-0.5.

[0007] Preferably, the temperature rising speed in step S1 is 2℃ / min.

[0008] Preferably, the temperature in the constant temperature oven in step S3 is 24-26℃.

[0009] Preferably, the pore size of the microporous filter membrane in step S is 0.45μm.

[0010] Preferably, the pressure in step S3 is 0.2MPa.

[0011] Preferably, the time for aging in the dark is 20-24h.

[0012] A blackening solution prepared according to the above preparation method.

[0013] The application of a blackening solution prepared according to the above preparation method in a copper metal grid conductive film.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The corrosion inhibitor modifier of the present invention works synergistically with the blackening modifier to improve the dispersion uniformity of the blackening liquid, form a dense, halo-free blackening layer and a hydrophobic film on the copper surface, enhance the leveling of the blackening liquid, block the penetration of corrosive media, and avoid uneven blackening at the edge of the copper grid with a line width of 2-5 μm.

[0015] 2. The blackening liquid of the present invention has a fast blackening speed and a blackening temperature close to room temperature, which significantly reduces the reflectivity and brightness of copper, achieving the effect of eliminating shadows, and has the advantages of no damage to the grid lines and no impact on the conductive properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of the preparation process of the blackening liquid of the present invention; Figure 2 This is a flow chart of the preparation process of the blackening modifier of the present invention; Figure 3 The present invention is a flow chart of the preparation process of the corrosion inhibitor modifier. DETAILED DESCRIPTION

[0017] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] See also Figure 1-3 , the present invention provides a technical solution: Example 1 A method for preparing a blackening liquid: Before preparing the blackening liquid, the corrosion inhibitor and blackening modifier are prepared: The preparation of the corrosion inhibitor modifier includes the following steps: S221. Add 2 g of catechol and 0.3 g of mercaptobenzothiazole to 15 g of ethanol solution in a 40°C water bath and stir at 200 rpm for 15 min to obtain an organic phase solution. S222. The water bath temperature was raised to 50°C, and 0.8 g of trisodium phosphate and 0.5 g of sodium benzoate were added to 5 g of ethanol solution and stirred at 250 rpm for 10 min to obtain an inorganic phase solution. S223. The organic phase solution and the inorganic phase solution were mixed, stirred at a speed of 150r / min for 20min, and aged for 20h in the dark to obtain a corrosion inhibitor modifier; The preparation of the blackening modifier comprises the following steps: S21. In a constant temperature water bath at 45 ° C, 9 g of fatty alcohol polyoxyethylene ether was mixed with 1.5 g of sodium dodecylbenzenesulfonate and stirred at 150 r / min for 10 min to obtain a clear solution; S22. Lower the water bath temperature to 40°C, add 2 g of corrosion inhibitor, and stir at 100 rpm for 15 min. S23. To the solution obtained in step S22, 0.1 g of polydimethylsiloxane was added, allowed to stand for 5 min, and then dispersed at 200 r / min for 2 min to obtain a blackening modifier; S1. Add 2 g of thiourea and 0.1 g of auxiliary alkali solution (potassium carbonate: triethanolamine: borax in a ratio of 1:0.5:0.3) to 45 ml of deionized water. While stirring at 200 rpm, heat the mixture to 40°C at a rate of 2°C / min and maintain for 10 min. S2. The solution of step S1 was heated to 49°C and stirred for 30 min to dissolve the solid. Then, 1 g of blackening modifier was added and stirred at a speed of 100 r / min for 5 min. S3. Add 45 ml of deionized water to the mixed solution obtained in step S2, stir at a speed of 150 r / min for 20 min, age in a constant temperature box at 24°C for 10 h, and then filter under pressure through a 0.45 μm microporous membrane at a pressure of 0.2 MPa to obtain a blackened liquid.

[0019] Example 2 A method for preparing a blackening liquid: Before preparing the blackening liquid, the corrosion inhibitor and blackening modifier are prepared: The preparation of the corrosion inhibitor modifier includes the following steps: S221. 4 g of catechol and 0.5 g of mercaptobenzothiazole were added to 20 g of ethanol solution in a 40°C water bath and stirred at 250 rpm for 20 min to obtain an organic phase solution; S222. The water bath temperature was raised to 50°C, and 1.2 g of trisodium phosphate and 0.8 g of sodium benzoate were added to 10 g of ethanol solution and stirred at 300 rpm for 15 min to obtain an inorganic phase solution. S223. The organic phase solution and the inorganic phase solution were mixed, stirred at a speed of 200r / min for 25min, and aged for 24h in the dark to obtain a corrosion inhibitor modifier; The preparation of the blackening modifier comprises the following steps: S21. In a constant temperature water bath at 45 ° C, 11 g of fatty alcohol polyoxyethylene ether was mixed with 2.5 g of sodium dodecylbenzenesulfonate and stirred at 200 r / min for 15 min to obtain a clear solution; S22. Lower the water bath temperature to 40°C, add 5 g of corrosion inhibitor, and stir at a low speed of 150 r / min for 20 min; S23. To the solution obtained in step S22, 0.2 g of polydimethylsiloxane was added, allowed to stand for 10 min, and then dispersed at 250 r / min for 4 min to obtain a blackening modifier; S1. Add 4 g of thiourea and 0.3 g of auxiliary alkaline solution (potassium carbonate: triethanolamine: borax in a ratio of 1:0.8:0.5) to 50 ml of deionized water. While stirring at 250 rpm, heat the mixture to 40°C at a rate of 2°C / min and maintain for 15 min. S2. The solution of step S1 was heated to 51°C and stirred for 35 min to dissolve the solid. Then, 1.7 g of blackening modifier was added and stirred at a speed of 200 r / min for 10 min. S3. Add 50 ml of deionized water to the mixed solution obtained in step S2, stir at a speed of 200 r / min for 30 min, age in a constant temperature box at 26°C for 12 h, and then filter under pressure through a 0.45 μm microporous membrane at a pressure of 0.2 MPa to obtain a blackened liquid.

[0020] Example 3 A method for preparing a blackening liquid: Before preparing the blackening liquid, the corrosion inhibitor and blackening modifier are prepared: The preparation of the corrosion inhibitor modifier includes the following steps: S221. 3 g of catechol and 0.4 g of mercaptobenzothiazole were added to 16 g of ethanol solution in a 40°C water bath and stirred at 220 rpm for 16 min to obtain an organic phase solution; S222. The water bath temperature was raised to 50°C, and 0.9 g of trisodium phosphate and 0.6 g of sodium benzoate were added to 6 g of ethanol solution and stirred at 270 rpm for 11 min to obtain an inorganic phase solution. S223. The organic phase solution and the inorganic phase solution were mixed, stirred at a speed of 170r / min for 22min, and aged in the dark for 21h to obtain a corrosion inhibitor modifier; The preparation of the blackening modifier comprises the following steps: S21. In a constant temperature water bath at 45°C, 10 g of fatty alcohol polyoxyethylene ether was mixed with 1.7 g of sodium dodecylbenzenesulfonate and stirred at 170 rpm for 11 min to obtain a clear solution. S22. Lower the water bath temperature to 40°C, add 3 g of corrosion inhibitor, and stir at 120 rpm for 17 min. S23. To the solution obtained in step S22, 0.12 g of polydimethylsiloxane was added, allowed to stand for 6 min, and then dispersed at 220 r / min for 3 min to obtain a blackening modifier; S1. Add 3 g of thiourea and 0.2 g of auxiliary alkali solution (potassium carbonate: triethanolamine: borax in a ratio of 1:0.6:0.4) to 46 ml of deionized water. While stirring at 220 rpm, heat the mixture to 40°C at a rate of 2°C / min and maintain for 12 min. S2. The solution of step S1 was heated to 50°C and stirred for 32 min until the solid was dissolved. Then 1.1 g of blackening modifier was added and stirred at a speed of 150 r / min for 6 min. S3. Add 47 ml of deionized water to the mixed solution obtained in step S2, stir at a speed of 170 r / min for 22 min, age in a constant temperature box at 25°C for 11 h, and then filter under pressure through a 0.45 μm microporous membrane at a pressure of 0.2 MPa to obtain a blackened liquid.

[0021] Example 4 A method for preparing a blackening liquid: Before preparing the blackening liquid, the corrosion inhibitor and blackening modifier are prepared: The preparation of the corrosion inhibitor modifier includes the following steps: S221. 3.5 g of catechol and 0.45 g of mercaptobenzothiazole were added to 18 g of ethanol solution in a 40°C water bath and stirred at 240 rpm for 18 min to obtain an organic phase solution; S222. Raise the water bath temperature to 50°C, add 1.1 g of trisodium phosphate and 0.7 g of sodium benzoate to 9 g of ethanol solution, and stir at 280 rpm for 14 min to obtain an inorganic phase solution; S223. The organic phase solution and the inorganic phase solution were mixed, stirred at a speed of 180r / min for 24min, and aged in the dark for 23h to obtain a corrosion inhibitor modifier; The preparation of the blackening modifier comprises the following steps: S21. In a constant temperature water bath at 45 ° C, 10.5 g of fatty alcohol polyoxyethylene ether was mixed with 2.2 g of sodium dodecylbenzene sulfonate and stirred at 180 r / min for 14 min to obtain a clear solution; S22. Lower the water bath temperature to 40°C, add 4 g of corrosion inhibitor, and stir at a low speed of 140 r / min for 18 min; S23. To the solution obtained in step S22, 0.18 g of polydimethylsiloxane was added, allowed to stand for 8 min, and then dispersed at 240 r / min for 3.5 min to obtain a blackening modifier; S1. Add 3.5 g of thiourea and 0.25 g of auxiliary alkaline solution (potassium carbonate: triethanolamine: borax in a ratio of 1:0.7:0.45) to 48 ml of deionized water. While stirring at 220 rpm, heat the mixture to 40°C at a rate of 2°C / min and maintain for 14 min. S2. The solution of step S1 was heated to 50°C and stirred for 34 min until the solid was dissolved. Then 1.6 g of blackening modifier was added and stirred at a speed of 180 r / min for 8 min. S3. Add 48 ml of deionized water to the mixture obtained in step S2, stir at a speed of 180 r / min for 26 min, age in a constant temperature box at 25°C for 11.5 h, and then filter under pressure through a 0.45 μm microporous membrane at a pressure of 0.2 MPa to obtain a blackened liquid.

[0022] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that no corrosion inhibitor modifier is added in Comparative Example 1, and the remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0023] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that no corrosion inhibitor and blackening modifier are added in Comparative Example 2, and the remaining steps are exactly the same in Comparative Example 2 and Example 1.

[0024] Performance testing: The blackening liquid obtained in Examples 1-4 and Comparative Examples 1-2 was applied to the metal grid conductive film, and the reflectivity, corrosion resistance, hydrophobicity, and conductivity were tested respectively. According to GB / T 9754-2007 "Determination of Specular Gloss of Paints and Varnishes", the BYK-micro-TRI-gloss multi-angle gloss meter was used to measure the reflectivity of 550nm visible light at an incident angle of 60°, and the average value was taken for each group of 9 points. According to GB / T 10125-2021 "Artificial Atmosphere Corrosion Test Salt Spray Test", a 5% NaCl solution was used and continuously sprayed at 35°C for 24 hours. The number of corrosion points on the edge of the grid was observed under a microscope, and the percentage of corrosion area was calculated. The contact angle of deionized water was determined by the sessile drop method, and 5 points were measured for each sample and the average value was taken. The square resistance was measured according to the four-point probe method, and the square resistance change rate before and after blackening was calculated. The calculation formula is: (R 后 -R 前 ) / R 前 ×100%. The final data is shown in Table 1 below: Table 1

[0025] The data in the table show that the reflectivity, corrosion resistance, hydrophobicity, and conductivity of the examples are significantly superior to those of the comparative examples, demonstrating that the synergistic effect of the corrosion inhibitor and blackening modifier effectively fills copper grain boundary defects, while the blackening agent optimizes leveling. Together, they address the problem of blackening at the edges of micron-scale meshes, reducing copper reflectivity and brightness, and achieving a shadow-eliminating effect. Furthermore, the phosphorus-free formulation of the present invention meets European and American emission standards.

[0026] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a blackening liquid, characterized in that: The method comprises the following preparation steps: S1. By mass, 2-4 parts of thiourea 0.1-0.3 parts of auxiliary alkali solution are added to 45-50 parts of deionized water, stirred at a speed of 200-250r / min, and slowly heated to 40 ° C and kept warm for 10-15min; S2. The solution of step S1 is heated to 49-51 ° C, and the temperature is maintained and stirred for 30-35 min until the solid is dissolved, and then 1-1.7 parts of the blackening modifier is added and stirred at a speed of 100-200 r / min for 5-10 min; S3. To the mixture obtained in step S2, 45-50 parts of deionized water was added, stirred at a speed of 150-200r / min for 20-30min, aged in an incubator for 10-12h, and then pressure filtered through a microporous membrane to obtain a black liquid; The preparation of the blackening modifier comprises the following steps: S21. In parts by mass, 9-11 parts of fatty alcohol polyoxyethylene ether were mixed with 1.5-2.5 parts of sodium dodecylbenzenesulfonate in a constant temperature water bath at 45 ° C, and stirred at a speed of 150-200 r / min for 10-15min to obtain a transparent solution; S22. Lower the water bath temperature to 40°C, add 2-5 parts of corrosion inhibitor, and stir at a low speed of 100-150 r / min for 15-20 min; S23. Add 0.1-0.2 parts of polydimethylsiloxane to the solution obtained in step S22, let it stand for 5-10 minutes, and then disperse it at 200-250 r / min for 2-4 minutes to obtain a blackening modifier.

2. The method for preparing a blackening liquid according to claim 1, characterized in that: The preparation of the corrosion inhibitor modifier comprises the following steps: S221. In parts by mass, 2-4 parts of catechol and 0.3-0.5 parts of mercaptobenzothiazole were added to 15-20 parts of ethanol solution in a water bath at 40 ° C and stirred at 200-250 r / min for 15-20 min to obtain an organic phase solution; S222. The water bath temperature was raised to 50°C, 0.8-1.2 parts of trisodium phosphate and 0.5-0.8 parts of sodium benzoate were added to 5-10 parts of ethanol solution and stirred at 250-300 r / min for 10-15 min to obtain an inorganic phase solution; S223. The organic phase solution and the inorganic phase solution are mixed, stirred at a speed of 150-200 r / min for 20-25 min, and matured in the dark to obtain a corrosion inhibitor modifier.

3. The method for preparing a blackening liquid according to claim 1, characterized in that: The auxiliary alkali solution consists of potassium carbonate, triethanolamine and borax in a mass ratio of 1:0.5-0.8:0.3-0.

5.

4. The method for preparing a blackening liquid according to claim 1, characterized in that: The heating rate of the slow heating in step S1 is 2°C / min.

5. The method for preparing a blackening liquid according to claim 1, characterized in that: The temperature in the thermostat in step S3 is 24-26°C.

6. The method for preparing a blackening liquid according to claim 1, characterized in that: The pore size of the microporous filter membrane in step S is 0.45 μm.

7. The method for preparing a blackening liquid according to claim 1, characterized in that: The pressure in step S3 is 0.2 MPa.

8. The method for preparing a blackening liquid according to claim 2, characterized in that: The time for maturation in the dark is 20-24 hours.

9. A blackening liquid prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the blackening liquid according to claim 9 in a copper metal grid conductive film.

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