Environment-friendly cyanide-free zincate zinc-plating brightener and preparation method thereof

Abstract

The invention relates to an environment-friendly cyanide-free zincate zinc plating brightener and a preparation method thereof, and relates to the technical field of metal surface treatment. The polishing solution comprises the following components in parts by mass: 10-30 parts of sulfonic modified p-chlorobenzalacetone, 10-20 parts of conjugated modified anisaldehyde, 15-40 parts of a compound auxiliary brightener, 5-15 parts of iso-tridecanol polyoxyethylene ether, 3-10 parts of polyethylene glycol, 2-8 parts of a displacement agent and 30-50 parts of ethylene glycol monobutyl ether. The preparation method comprises the following steps: adding sulfo-modified p-chlorobenzylidene acetone into ethylene glycol monobutyl ether under a water bath heating condition, uniformly stirring, sequentially adding conjugated modified anisaldehyde, iso-tridecanol polyoxyethylene ether, polyethylene glycol, a compound auxiliary brightener and a displacement agent, stirring after each component is added, and uniformly stirring to obtain a mixture; and after the addition is finished, increasing the rotating speed and continuously stirring to obtain the environment-friendly cyanide-free zincate zinc-plating brightener. The brightening agent has the effect of improving the dispersing performance of the brightening agent, and the uniformity and the brightening effect of a plating layer can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of metal surface treatment, and in particular to an environmentally friendly cyanide-free zincate zinc plating brightener and a preparation method thereof. Background Art

[0002] The galvanizing process is one of the important technologies for metal surface treatment and is widely used in the automotive, home appliance, construction and other industries to improve the corrosion resistance and appearance of the products. The traditional galvanizing process mostly uses a cyanide-containing plating solution. Although cyanide has good electrochemical properties, its highly toxic nature poses a serious threat to the environment and operators. In recent years, with the enhancement of environmental awareness and technological progress, cyanide-free zinc plating technology has gradually become a research hotspot, especially cyanide-free zincate zinc plating technology has attracted widespread attention due to its environmental advantages.

[0003] At present, the cyanide-free zincate zinc plating process is mainly achieved by adjusting the composition of the plating solution. Commonly used cyanide-free zincate plating solutions usually include zincate, complexing agent, brightener and stabilizer. Zincate is used as the main salt to provide zinc ions; the complexing agent is used to control the release rate of zinc ions and maintain the stability of the plating solution; the brightener is used to improve the gloss and flatness of the coating; the stabilizer is to prevent the decomposition and precipitation of the plating solution. In addition, some auxiliary components, such as buffers and conductive agents, are often added to further optimize the performance of the plating solution.

[0004] However, the existing cyanide-free zincate zinc plating brightener has some defects. The brightener has insufficient dispersibility. When deposited on workpieces with complex shapes and large areas, the coating thickness will be uneven, resulting in unstable coating quality, so it needs to be improved. Summary of the invention

[0005] In order to improve the dispersibility of the brightener, the present application provides an environmentally friendly cyanide-free zincate zinc plating brightener and a preparation method thereof.

[0006] The present application provides an environmentally friendly cyanide-free zincate zinc plating brightener and a preparation method thereof, which adopts the following technical solutions: In the first aspect, the present application provides an environmentally friendly cyanide-free zincate zinc plating brightener, which adopts the following technical solutions: An environmentally friendly cyanide-free zincate zinc plating brightener comprises the following components in parts by weight: Sulfonic acid modified p-chlorobenzylideneacetone 10-30 parts Conjugated modified anisaldehyde 10-20 parts Compound auxiliary brightener 15-40 parts 5-15 parts of isomeric tridecanol polyoxyethylene ether 3-10 parts of polyethylene glycol 2-8 parts of moving agent 30-50 parts of ethylene glycol monobutyl ether.

[0007] The introduction of sulfonic acid groups into sulfonic acid modified parachlorobenzylideneacetone enhances its water solubility and dispersibility. When zinc ions are deposited, the rate and mode of deposition are adjusted, so that the crystallization of the zinc coating is more delicate and uniform, thereby improving the gloss of the coating. The conjugated structure in the conjugated modified anisaldehyde can absorb and reflect light of a specific wavelength, so that the surface of the coating presents a good gloss. During the zincate zinc plating process, it can be adsorbed on the surface of the coating and synergize with sulfonic acid modified parachlorobenzylideneacetone to adjust the deposition direction and rate of zinc ions, thereby promoting the formation of a smoother and brighter coating. The compound auxiliary brightener refines the crystallization of the coating through the synergistic effect between the components, improves the gloss of the coating, and improves the gloss of the coating. Improve the uniformity of the brightening effect and enhance the stability of the brightener; isomeric tridecanol polyoxyethylene ether can reduce the surface tension of the plating solution, promote the spreading of the brightener and the dispersion between the components, prevent the occurrence of agglomeration and stratification, and improve the uniformity and stability of the brightener; polyethylene glycol has good hydrophilicity and can interact with other components in the brightener to make them evenly dispersed in the plating solution, transport the effective ingredients to the surface of the plated part, and synergistically improve the quality of the coating; the moving agent can effectively improve the dispersing ability of the plating solution, enable zinc ions to be evenly deposited on the surface of complex plated parts, and synergize with other ingredients to improve the uniformity and brightening effect of the coating.

[0008] Preferably, the raw materials for preparing the sulfonic acid group-modified p-chlorobenzylideneacetone include p-chlorobenzylideneacetone and chlorosulfonic acid.

[0009] Chlorosulfonic acid introduces sulfonic acid groups into 4-chlorobenzylideneacetone. The sulfonic acid groups have strong hydrophilicity and ionization properties, which enhance the solubility of the modified 4-chlorobenzylideneacetone in the plating solution. At the same time, they can produce electrostatic repulsion or attraction with other charged particles in the plating solution, thereby effectively preventing self-agglomeration and improving dispersibility. In the galvanizing process, good dispersibility can ensure that it is evenly distributed throughout the plating solution to regulate the deposition process of zinc ions. It is adsorbed on the surface when the coating grows, and interacts with zinc ions through its special chemical structure to guide the orderly deposition of zinc ions, reduce defects caused by uneven deposition, and thus improve the uniformity of the coating, so that the coating presents a uniform and consistent appearance on a macroscopic scale. This orderly deposition makes the coating crystallization more delicate and regular, and ultimately effectively improves the brightening effect of the coating.

[0010] Preferably, the raw materials for preparing the conjugated modified anisaldehyde include anisaldehyde entity and diethyl malonate.

[0011] Anisaldehyde reacts with diethyl malonate to introduce a conjugated structure, which enhances the compatibility and stability of the conjugated modified anisaldehyde in the brightener system; this conjugated system can produce multiple interactions such as π-π stacking and hydrogen bonding with metal ions and other organic components in the plating solution, so that the conjugated modified anisaldehyde is evenly dispersed in the plating solution to avoid the occurrence of local concentrations that are too high or too low. During zincate zinc plating, the conjugated modified anisaldehyde is evenly adsorbed on the surface of the coating, and through synergistic action with zinc ions and other additives, the zinc ions are guided to deposit in a specific direction and rate, effectively reducing defects and irregularities in the growth process of the coating, making the coating crystallization more fine and uniform, and improving the flatness and brightening effect of the coating.

[0012] Preferably, the raw materials for preparing the composite auxiliary brightener include 2-aminobenzamide, cinnamic acid and modified sodium naphthalenesulfonate.

[0013] 2-aminobenzamide has a conjugated system of nitrogen atom and benzene ring, and can produce π-π stacking effect with the conjugated structure of sulfonic acid modified 4-chlorobenzylideneacetone. At the same time, 2-aminobenzamide has polarity and can interact with sulfonic acid groups. This multiple interaction can effectively improve the dispersibility of the brightener, and can adjust the zinc ion deposition path during zincate zinc plating, and promote the crystallization refinement of the coating. Cinnamic acid can be co-adsorbed with conjugated modified vanillin on the surface of the electrode, guide the orderly deposition of zinc ions, and complement and synergize with conjugated modified vanillin to effectively improve the flatness and brightness of the coating. Modified sodium naphthalenesulfonate can simultaneously promote the dispersibility of sulfonic acid modified 4-chlorobenzylideneacetone and conjugated modified vanillin, so that zinc ions are uniformly deposited and the uniformity of the coating is improved. After the three are compounded, they synergize with each other to further improve the dispersibility of the brightener. During zinc plating, the zinc ion deposition process can be optimized from multiple angles, the coating defects can be reduced, and the uniformity, density and brightness of the coating can be improved.

[0014] Preferably, the raw materials for preparing the modified sodium naphthalenesulfonate include sodium naphthalenesulfonate body, ammonium persulfate and cetylpyridinium chloride.

[0015] Ammonium persulfate can promote the self-polymerization of sodium naphthalenesulfonate and improve its dispersibility through steric hindrance; hexadecylpyridinium chloride grafts quaternary ammonium salt groups onto the surface of sodium naphthalenesulfonate, enhances the cationicity of sodium naphthalenesulfonate, and improves its adsorption performance in the plating solution. It can be effectively adsorbed on the surface of the zinc layer, and assists the sulfonic acid group modification to better regulate the deposition behavior of zinc ions with chlorobenzylidene acetone and conjugated modified vanillin, making the coating crystallization more dense and uniform, thereby improving the uniformity and brightening effect of the coating.

[0016] Preferably, the modified sodium naphthalenesulfonate is prepared by the following steps: Dispersing sodium naphthalenesulfonate in water to obtain a sodium naphthalenesulfonate solution, adding ammonium persulfate to the sodium naphthalenesulfonate solution under stirring, heating and stirring for reaction, after cooling, pouring anhydrous ethanol into the solution for precipitation, filtering and collecting the precipitate, washing the precipitate with anhydrous ethanol, and vacuum drying the washed precipitate to obtain polysodium naphthalenesulfonate; The prepared sodium polynaphthalene sulfonate is dispersed in N,N-dimethylformamide to obtain a sodium polynaphthalene sulfonate solution, and cetylpyridine chloride is added to the sodium polynaphthalene sulfonate solution. The temperature is raised and stirred for reaction. After cooling, ice water is added for precipitation to obtain a product. The product is washed with ice water and vacuum dried to obtain modified sodium naphthalene sulfonate.

[0017] Preferably, the mass ratio of the sodium naphthalenesulfonate body, ammonium persulfate and cetylpyridinium chloride is 1:0.05:(0.02-0.08).

[0018] The modified sodium naphthalenesulfonate prepared according to the above steps and mass ratio has good performance and can effectively improve the dispersibility of the brightener, thereby improving the quality and brightening effect of the coating.

[0019] Preferably, the displacement agent comprises carboxyethyl isothiourea chloride, sodium hydroxymethanesulfonate and 2-mercaptobenzimidazole.

[0020] Carboxyethyl isothiourea chloride can ionize charged groups in the plating solution, and guide zinc ions to migrate to the low current density area of ​​the plated parts by changing the electric field distribution, thereby improving the dispersibility of the plating solution and ensuring uniform deposition of the coating on complex-shaped plated parts; Sodium hydroxymethyl sulfonate has good water solubility and coordination ability, and can form a weak coordination complex with zinc ions. During the electroplating process, it changes the deposition potential of zinc ions, further promoting the uniform deposition of zinc ions in various parts of the plated parts, which is beneficial to improving the deep plating ability, so that the depressions and pores of the plated parts can also obtain a good coating; The heterocyclic structure of 2-mercaptobenzimidazole enables it to be adsorbed on the surface of the coating, providing special active sites for zinc ion deposition, and synergistically acting with carboxyethyl isothiourea chloride to enhance the regulation of electric field distribution, allowing zinc ions to migrate to various parts of the plated parts, further improving the dispersion capacity of the plating solution. At the same time, its adsorption characteristics help to stabilize the weak coordination complex formed by sodium hydroxymethyl sulfonate and zinc ions, optimize the regulation effect of zinc ion deposition potential, promote uniform and orderly deposition of zinc ions on the surface of the plated parts, reduce defects caused by uneven deposition, and jointly improve the density and flatness of the coating.

[0021] Preferably, the mass ratio of carboxyethyl isothiourea chloride, sodium hydroxymethanesulfonate and 2-mercaptobenzimidazole is (0.02-0.05):1:0.5.

[0022] The displacement agent compounded according to the above mass ratio can effectively improve the uniformity and brightness of the coating.

[0023] In a second aspect, the present application provides a method for preparing an environmentally friendly cyanide-free zincate zinc plating brightener, using the following technical solution: A method for preparing an environmentally friendly cyanide-free zincate zinc plating brightener comprises the following steps: The sulfonic acid modified p-chlorobenzylideneacetone is added to ethylene glycol monobutyl ether under water bath heating conditions. After stirring evenly, the conjugated modified anisaldehyde, isomeric tridecanol polyoxyethylene ether, polyethylene glycol, compound auxiliary brightener and moving agent are added in sequence. Stirring is performed after each ingredient is added. After the addition is completed, the speed is increased and stirring is continued to obtain an environmentally friendly cyanide-free zincate zinc plating brightener.

[0024] The environmentally friendly cyanide-free zincate zinc plating brightener prepared according to the above steps has good dispersibility, can be evenly distributed in the plating solution, effectively improves the uniformity and density of the coating, and the coating has a good brightening effect.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. The introduction of sulfonic acid groups into sulfonic acid modified parachlorobenzylideneacetone enhances its water solubility and dispersibility. When zinc ions are deposited, the rate and mode of deposition are adjusted to make the crystallization of the zinc coating more delicate and uniform, thereby improving the gloss of the coating. The conjugated structure in the conjugated modified anisaldehyde can absorb and reflect light of a specific wavelength, making the coating surface present a good gloss. During the zincate zinc plating process, it can be adsorbed on the coating surface and synergize with sulfonic acid modified parachlorobenzylideneacetone to adjust the deposition direction and rate of zinc ions, thereby promoting the formation of a smoother and brighter coating. The compound auxiliary brightener refines the coating crystallization through the synergistic effect between the components. Improve the uniformity of the brightening effect and enhance the stability of the brightener; isomeric tridecanol polyoxyethylene ether can reduce the surface tension of the plating solution, promote the spreading of the brightener and the dispersion between the components, prevent the occurrence of agglomeration and stratification, and improve the uniformity and stability of the brightener; polyethylene glycol has good hydrophilicity and can interact with other components in the brightener to make them evenly dispersed in the plating solution, transport the effective ingredients to the surface of the plated part, and synergistically improve the quality of the coating; the moving agent can effectively improve the dispersing ability of the plating solution, enable zinc ions to be evenly deposited on the surface of complex plated parts, and synergize with other ingredients to improve the uniformity and brightening effect of the coating.

[0026] 2. The 2-aminobenzamide in the composite auxiliary brightener has a conjugated system of nitrogen atom and benzene ring, which can produce π-π stacking effect with the conjugated structure of sulfonic acid modified chlorobenzylideneacetone. At the same time, 2-aminobenzamide has polarity and can interact with sulfonic acid groups. This multiple interaction can effectively improve the dispersibility of the brightener, regulate the zinc ion deposition path during zincate zinc plating, and promote the crystallization and refinement of the coating; cinnamic acid can be adsorbed together with conjugated modified vanillin on the surface of the electrode, guiding Zinc ions are deposited in an orderly manner, complementing and synergizing with conjugated modified vanillin to effectively improve the flatness and brightness of the coating; modified sodium naphthalenesulfonate can simultaneously promote the dispersibility of sulfonic acid-modified chlorobenzylidene acetone and conjugated modified vanillin, so that zinc ions are deposited evenly and the uniformity of the coating is improved; after using the three in combination, they synergize with each other and further improve the dispersibility of the brightener. During galvanizing, the zinc ion deposition process can be optimized from multiple angles, the defects of the coating can be reduced, and the uniformity, density and brightness of the coating can be improved.

[0027] 3. Carboxyethyl isothiourea chloride can ionize charged groups in the plating solution, and guide zinc ions to migrate to the low current density area of ​​the plated parts by changing the electric field distribution, thereby improving the dispersibility of the plating solution and ensuring uniform deposition of the coating on complex-shaped plated parts; Sodium hydroxymethyl sulfonate has good water solubility and coordination ability. It can form a weak coordination complex with zinc ions. During the electroplating process, it changes the deposition potential of zinc ions, further promoting the uniform deposition of zinc ions in various parts of the plated parts, which is beneficial to improving the deep plating ability, so that the depressions and pores of the plated parts can also obtain a good coating. The heterocyclic structure of 2-mercaptobenzimidazole enables it to be adsorbed on the surface of the coating, providing special active sites for zinc ion deposition, and synergistically acting with carboxyethyl isothiourea chloride to enhance the regulation of electric field distribution, allowing zinc ions to migrate to various parts of the plated parts, further improving the dispersibility of the plating solution. At the same time, its adsorption characteristics help to stabilize the weak coordination complex formed by sodium hydroxymethyl sulfonate and zinc ions, optimize the regulation effect of zinc ion deposition potential, promote uniform and orderly deposition of zinc ions on the surface of the plated parts, reduce defects caused by uneven deposition, and jointly improve the density and flatness of the coating. DETAILED DESCRIPTION

[0028] The present application discloses an environmentally friendly cyanide-free zincate zinc plating brightener and a preparation method thereof. The raw materials used in the present application can be obtained from commercially available raw materials unless otherwise specified. The present application is further described in detail in conjunction with the embodiments below: Ingredients: p-Chlorobenzyl acetone (CAS No.: 122-57-6), chlorosulfonic acid (CAS No.: 7790-94-5), anisaldehyde (CAS No.: 123-11-5), diethyl malonate (CAS No.: 105-53-3), sodium ethoxide (CAS No.: 141-52-6), sodium naphthalenesulfonate (CAS No.: 1321-69-3), ammonium persulfate (CAS No.: 7727-54-0), cetylpyridinium chloride (CAS No.: 6004-24-6), ethylene glycol monobutyl ether (CAS No.: 1321-69-3). S No.: 111-76-2), isomeric tridecanol polyoxyethylene ether (CAS No.: 9043-30-5), polyethylene glycol is PEG-400 (CAS No.: 25322-68-3), 2-aminobenzamide (CAS No.: 88-68-6), cinnamic acid (CAS No.: 140-10-3), carboxyethyl isothiourea chloride (CAS No.: 5425-78-5), sodium hydroxymethyl sulfonate (CAS No.: 870-72-4), 2-mercaptobenzimidazole (CAS No.: 583-39-1).

[0029] Example 1 Preparation of sulfonic acid modified p-chlorobenzylideneacetone Place 35 g of p-chlorobenzylideneacetone in an ice-water bath and stir at 100 rpm. Add 25 g of chlorosulfonic acid within 1 hour. After the addition is completed, heat to 40°C and stir at 200 rpm for 3 hours. After the reaction is completed, pour the reaction solution into ice water and stir at 200 rpm. After the solid is precipitated, filter and collect the solid, and recrystallize the solid with anhydrous ethanol to obtain sulfonic acid-modified p-chlorobenzylideneacetone.

[0030] Preparation of conjugated modified anisaldehyde Disperse 20 g of anisaldehyde and 23.5 g of diethyl malonate in 100 mL of anhydrous ethanol, stir at 200 rpm until fully dissolved to obtain a modified liquid; add 10 g of sodium ethoxide to the modified liquid, heat to 80°C and stir at 200 rpm to react for 4 hours, cool to below 30°C, pour the modified liquid after the reaction into ice water, adjust the pH to 4 with hydrochloric acid, precipitate the product, collect the precipitate by filtration, wash with deionized water, and dry in vacuo at 60°C to obtain conjugated modified anisaldehyde.

[0031] Preparation of modified sodium naphthalenesulfonate 46.73 g of sodium naphthalenesulfonate was dispersed in 500 mL of deionized water to obtain a sodium naphthalenesulfonate solution. Under stirring at a speed of 200 rpm, 2.34 g of ammonium persulfate was added to the sodium naphthalenesulfonate solution. The temperature was raised to 80° C. and stirred at a speed of 200 rpm for 4 hours. After cooling to 30° C., anhydrous ethanol was poured into the solution for precipitation. The precipitate was collected by filtration, and the precipitate was washed with anhydrous ethanol. The washed precipitate was vacuum dried at 60° C. to obtain polysodium naphthalenesulfonate.

[0032] The prepared sodium polynaphthalene sulfonate was dispersed in 500 mL of N, N-dimethylformamide to obtain a sodium polynaphthalene sulfonate solution, 0.93 g of hexadecylpyridine chloride was added to the sodium polynaphthalene sulfonate solution, the temperature was raised to 100 ° C, and the reaction was stirred at 300 rpm for 4 hours. After cooling to 30 ° C, ice water was added for precipitation to obtain a product, the product was washed with ice water, and vacuum dried at 60 ° C to obtain modified sodium naphthalene sulfonate.

[0033] Preparation of environmentally friendly cyanide-free zincate zinc plating brightener In a 40°C water bath, 10g of sulfonic acid modified p-chlorobenzylideneacetone was added to 30g of ethylene glycol monobutyl ether, and after stirring evenly at a speed of 200rpm, 10g of conjugated modified anisaldehyde, 5g of isomeric tridecanol polyoxyethylene ether, 3g of polyethylene glycol, 15g of compound auxiliary brightener and 2g of moving agent were added in sequence. The mass ratio of 2-aminobenzamide, cinnamic acid and modified sodium naphthalenesulfonate in the compound auxiliary brightener was 1:1.5:2, and the mass ratio of carboxyethyl isothiourea chloride, sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole in the moving agent was 0.02:1:0.5. After each ingredient was added, it was stirred at a speed of 200rpm for 10min. After the addition was completed, the speed was increased to 300rpm and stirring was continued for 1h to obtain an environmentally friendly cyanide-free zincate zinc plating brightener.

[0034] Example 2 Preparation of sulfonic acid modified p-chlorobenzylideneacetone Place 35 g of p-chlorobenzylideneacetone in an ice-water bath and stir at 100 rpm. Add 25 g of chlorosulfonic acid within 1 hour. After the addition is completed, heat to 40°C and stir at 200 rpm for 3 hours. After the reaction is completed, pour the reaction solution into ice water and stir at 200 rpm. After the solid is precipitated, filter and collect the solid, and recrystallize the solid with anhydrous ethanol to obtain sulfonic acid-modified p-chlorobenzylideneacetone.

[0035] Preparation of conjugated modified anisaldehyde Disperse 20 g of anisaldehyde and 23.5 g of diethyl malonate in 100 mL of anhydrous ethanol, stir at 200 rpm until fully dissolved to obtain a modified liquid; add 10 g of sodium ethoxide to the modified liquid, heat to 80°C and stir at 200 rpm to react for 4 hours, cool to below 30°C, pour the modified liquid after the reaction into ice water, adjust the pH to 4 with hydrochloric acid, precipitate the product, collect the precipitate by filtration, wash with deionized water, and dry in vacuo at 60°C to obtain conjugated modified anisaldehyde.

[0036] Preparation of modified sodium naphthalenesulfonate 44.25 g of sodium naphthalenesulfonate was dispersed in 500 mL of deionized water to obtain a sodium naphthalenesulfonate solution. Under stirring at a speed of 200 rpm, 2.21 g of ammonium persulfate was added to the sodium naphthalenesulfonate solution. The temperature was raised to 80° C. and stirred at a speed of 200 rpm for 4 hours. After cooling to 30° C., anhydrous ethanol was poured into the solution for precipitation. The precipitate was collected by filtration, and the precipitate was washed with anhydrous ethanol. The washed precipitate was vacuum dried at 60° C. to obtain polysodium naphthalenesulfonate.

[0037] The prepared sodium polynaphthalene sulfonate was dispersed in 500 mL of N, N-dimethylformamide to obtain a sodium polynaphthalene sulfonate solution, 3.54 g of chlorohexadecylpyridine was added to the sodium polynaphthalene sulfonate solution, the temperature was raised to 100 ° C, and the reaction was stirred at 300 rpm for 4 hours. After cooling to 30 ° C, ice water was added for precipitation to obtain a product. The product was washed with ice water and vacuum dried at 60 ° C to obtain modified sodium naphthalene sulfonate.

[0038] Preparation of environmentally friendly cyanide-free zincate zinc plating brightener In a 40°C water bath, 30g of sulfonic acid modified p-chlorobenzylideneacetone was added to 50g of ethylene glycol monobutyl ether, and after stirring evenly at a speed of 200rpm, 20g of conjugated modified anisaldehyde, 15g of isomeric tridecanol polyoxyethylene ether, 10g of polyethylene glycol, 40g of compound auxiliary brightener and 8g of moving agent were added in sequence. The mass ratio of 2-aminobenzamide, cinnamic acid and modified sodium naphthalenesulfonate in the compound auxiliary brightener was 1:1.5:2, and the mass ratio of carboxyethyl isothiourea chloride, sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole in the moving agent was 0.05:1:0.5. After each ingredient was added, it was stirred at a speed of 200rpm for 10min. After the addition was completed, the speed was increased to 300rpm and stirring was continued for 1h to obtain an environmentally friendly cyanide-free zincate zinc plating brightener.

[0039] Example 3 Preparation of sulfonic acid modified p-chlorobenzylideneacetone Place 35 g of p-chlorobenzylideneacetone in an ice-water bath and stir at 100 rpm. Add 25 g of chlorosulfonic acid within 1 hour. After the addition is completed, heat to 40°C and stir at 200 rpm for 3 hours. After the reaction is completed, pour the reaction solution into ice water and stir at 200 rpm. After the solid is precipitated, filter and collect the solid, and recrystallize the solid with anhydrous ethanol to obtain sulfonic acid-modified p-chlorobenzylideneacetone.

[0040] Preparation of conjugated modified anisaldehyde Disperse 20 g of anisaldehyde and 23.5 g of diethyl malonate in 100 mL of anhydrous ethanol, stir at 200 rpm until fully dissolved to obtain a modified liquid; add 10 g of sodium ethoxide to the modified liquid, heat to 80°C and stir at 200 rpm to react for 4 hours, cool to below 30°C, pour the modified liquid after the reaction into ice water, adjust the pH to 4 with hydrochloric acid, precipitate the product, collect the precipitate by filtration, wash with deionized water, and dry in vacuo at 60°C to obtain conjugated modified anisaldehyde.

[0041] Preparation of modified sodium naphthalenesulfonate 45.46 g of sodium naphthalenesulfonate was dispersed in 500 mL of deionized water to obtain a sodium naphthalenesulfonate solution. Under stirring at a speed of 200 rpm, 2.27 g of ammonium persulfate was added to the sodium naphthalenesulfonate solution. The temperature was raised to 80° C. and stirred at a speed of 200 rpm for 4 hours. After cooling to 30° C., anhydrous ethanol was poured into the solution for precipitation. The precipitate was collected by filtration, and the precipitate was washed with anhydrous ethanol. The washed precipitate was vacuum dried at 60° C. to obtain polysodium naphthalenesulfonate.

[0042] The prepared sodium polynaphthalene sulfonate was dispersed in 500 mL of N, N-dimethylformamide to obtain a sodium polynaphthalene sulfonate solution, 2.27 g of chlorohexadecylpyridine was added to the sodium polynaphthalene sulfonate solution, the temperature was raised to 100 ° C, and the reaction was stirred at 300 rpm for 4 hours. After cooling to 30 ° C, ice water was added for precipitation to obtain a product, the product was washed with ice water, and vacuum dried at 60 ° C to obtain modified sodium naphthalene sulfonate.

[0043] Preparation of environmentally friendly cyanide-free zincate zinc plating brightener In a 40°C water bath, 20g of sulfonic acid modified p-chlorobenzylideneacetone was added to 40g of ethylene glycol monobutyl ether, and after stirring evenly at a speed of 200rpm, 15g of conjugated modified anisaldehyde, 10g of isomeric tridecanol polyoxyethylene ether, 6.5g of polyethylene glycol, 22.5g of compound auxiliary brightener and 5g of moving agent were added in sequence. The mass ratio of 2-aminobenzamide, cinnamic acid and modified sodium naphthalenesulfonate in the compound auxiliary brightener was 1:1.5:2, and the mass ratio of carboxyethyl isothiourea chloride, sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole in the moving agent was 0.035:1:0.5. After each component was added, it was stirred at a speed of 200rpm for 10min. After the addition was completed, the speed was increased to 300rpm and stirring was continued for 1h to obtain an environmentally friendly cyanide-free zincate zinc plating brightener.

[0044] Example 4 Example 4 is based on Example 3. The only difference between Example 4 and Example 3 is that in Example 4, no cetylpyridinium chloride is added to the modified sodium naphthalenesulfonate, the amount of sodium naphthalenesulfonate used is 47.62 g, and the amount of ammonium persulfate used is 2.38 g.

[0045] Example 5 Example 5 is based on Example 3. The only difference between Example 5 and Example 3 is that in Example 5, the amount of sodium naphthalenesulfonate is 42.73 g, the amount of ammonium persulfate is 2.14 g, and the amount of cetylpyridinium chloride is 5.13 g.

[0046] Example 6 Example 6 is based on Example 3, and the only difference between Example 6 and Example 3 is that in Example 6, modified sodium naphthalenesulfonate is replaced by sodium naphthalenesulfonate.

[0047] Example 7 Example 7 is based on Example 3, and the only difference between Example 7 and Example 3 is that cinnamic acid is not added in Example 7.

[0048] Example 8 Example 8 is based on Example 3. The only difference between Example 8 and Example 3 is that 2-aminobenzamide and cinnamic acid are not added in Example 8.

[0049] Example 9 Example 9 is based on Example 3. The only difference between Example 9 and Example 3 is that in Example 9, the mass ratio of carboxyethyl isothiourea chloride, sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole is 0.01:1:0.5.

[0050] Example 10 Example 10 is based on Example 3. The only difference between Example 10 and Example 3 is that in Example 10, the mass ratio of carboxyethyl isothiourea chloride, sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole is 0.07:1:0.5.

[0051] Embodiment 11 Example 11 is based on Example 3. The only difference between Example 11 and Example 3 is that in Example 11, sodium hydroxymethane sulfonate and 2-mercaptobenzimidazole are not added to the displacement agent.

[0052] Comparative Example 1 Comparative Example 1 is based on Example 3, and the only difference between Comparative Example 1 and Example 3 is that in Comparative Example 1, the sulfonic acid group-modified p-chlorobenzylidene acetone is replaced by p-chlorobenzylidene acetone.

[0053] Comparative Example 2 Comparative Example 2 is based on Example 3, and the only difference between Comparative Example 2 and Example 3 is that in Comparative Example 2, conjugated modified anisaldehyde is replaced by anisaldehyde.

[0054] Performance testing Brightener performance test: select an iron sheet of 10cm*10cm*0.5mm as the object to be electroplated, use alkali solution to degrease, rinse with hot water and rinse with deionized water, and then blow dry to obtain the pretreated iron sheet for use; conduct a Hull cell experiment, and electroplate the pretreated iron sheet in a 250mL Hull cell. The plating solution contains 220g / L potassium chloride, 65g / L zinc chloride, 30g / L boric acid and 1mL / L sample, the electroplating temperature is 25℃, and the current density is 1A / dm 2 , electroplating for 15 minutes, test the thickness of each sample at 1 cm away from the two end points on the diagonal line (recorded as the first point and the third point) and the center point (recorded as the second point), calculate the coating thickness, and record the results in Table 1; under the lighting condition of 50W fluorescent lamp, observe the appearance of the coating on the electroplated iron sheet at a distance of 40 cm from the fluorescent lamp, and the results are recorded in Table 1.

[0055] Table 1 Test results of brightener dispersibility and brightening effect It can be seen from Table 1 that the difference in thickness between the three sites of Examples 1-3 is less than 0.27 μm, and the coating is smooth and has high gloss, which shows that the brightener prepared in the present application has good dispersibility and brightening effect.

[0056] As can be seen from Table 1, the only difference between Examples 4 and 5 and Example 3 is that: in Example 4, no cetylpyridinium chloride is added to the modified sodium naphthalenesulfonate, and in Example 5, the mass ratio of sodium naphthalenesulfonate, ammonium persulfate and cetylpyridinium chloride is 1:0.05:0.12. Compared with Example 3, the uniformity of the coating thickness in Examples 4 and 5 is reduced; this is because without the addition of cetylpyridinium chloride, the dispersibility and adsorption of the modified sodium naphthalenesulfonate are reduced, the auxiliary effect of the main brightener is weakened, the dispersibility of the brightener is reduced, and the uniformity of the coating is reduced; adding excessive cetylpyridinium chloride, too much hydrophobic cetyl will affect the water solubility and dispersibility of the modified sodium naphthalenesulfonate, and the dispersibility of the brightener is also affected.

[0057] As can be seen from Table 1, the only difference between Examples 6, 7, and 8 and Example 3 is that in Example 6, modified sodium naphthalenesulfonate is replaced by sodium naphthalenesulfonate, in Example 7, cinnamic acid is not added, and in Example 8, 2-aminobenzamide and cinnamic acid are not added. Compared with Example 3, in Examples 6, 7, and 8, the uniformity of the coating thickness decreases and the brightening effect becomes worse; this is because sodium naphthalenesulfonate lacks modification treatment, and its dispersibility and adsorption properties decrease; and by reducing the types of auxiliary brighteners, the synergistic effect between the components decreases, and the performance of the brightener is further reduced, thereby reducing the dispersibility and brightening effect, and the uniformity of the coating decreases.

[0058] As can be seen from Table 1, the only difference between Examples 9, 10, and 11 and Example 3 is that the mass ratio of the components in Examples 9 and 10 is changed, and sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole are not added in Example 11. Compared with Example 3, Examples 9, 10, and 11 have decreased uniformity of the coating and worse brightening effect; this is because changing the component ratio will affect the synergistic effect between the moving agents, and reducing the components will further weaken the synergistic effect between the components, thereby affecting the dispersion performance, and the coating uniformity and brightening effect are reduced.

[0059] As can be seen from Table 1, the only difference between Comparative Examples 1 and 2 and Example 3 is that: in Comparative Example 1, the sulfonic acid group-modified p-chlorobenzylideneacetone is replaced by p-chlorobenzylideneacetone, and in Comparative Example 2, the conjugated modified anisaldehyde is replaced by anisaldehyde. Compared with Example 3, the uniformity and brightening effect of the coating in Comparative Examples 1 and 2 are greatly reduced; this is because the main brightener lacks modification treatment, its dispersibility is greatly reduced, and the concentration in the plating solution is locally too high or too low, which affects the deposition and growth of zinc ions, reduces the uniformity of the coating, and deteriorates the brightening effect.

[0060] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of ​​the present application. The technical scope of the present application is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An environmentally friendly cyanide-free zincate zinc plating brightener, characterized in that: The composition includes the following components in parts by weight: Sulfonic acid modified p-chlorobenzylideneacetone 10-30 parts Conjugated modified anisaldehyde 10-20 parts Compound auxiliary brightener 15-40 parts 5-15 parts of isomeric tridecanol polyoxyethylene ether 3-10 parts of polyethylene glycol 2-8 parts of moving agent 30-50 parts of ethylene glycol monobutyl ether.

2. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 1, characterized in that: The raw materials for preparing the sulfonic acid group-modified p-chlorobenzylideneacetone include p-chlorobenzylideneacetone and chlorosulfonic acid.

3. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 1, characterized in that: The raw materials for preparing the conjugated modified anisaldehyde include anisaldehyde body and diethyl malonate.

4. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 1, characterized in that: The raw materials for preparing the composite auxiliary brightener include 2-aminobenzamide, cinnamic acid and modified sodium naphthalenesulfonate.

5. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 4, characterized in that: The raw materials for preparing the modified sodium naphthalenesulfonate include sodium naphthalenesulfonate body, ammonium persulfate and cetylpyridinium chloride.

6. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 5, characterized in that: The modified sodium naphthalenesulfonate is prepared by the following steps: Dispersing sodium naphthalenesulfonate in water to obtain a sodium naphthalenesulfonate solution, adding ammonium persulfate to the sodium naphthalenesulfonate solution under stirring, heating and stirring for reaction, after cooling, pouring anhydrous ethanol into the solution for precipitation, filtering and collecting the precipitate, washing the precipitate with anhydrous ethanol, and vacuum drying the washed precipitate to obtain polysodium naphthalenesulfonate; The prepared sodium polynaphthalene sulfonate is dispersed in N,N-dimethylformamide to obtain a sodium polynaphthalene sulfonate solution, and cetylpyridine chloride is added to the sodium polynaphthalene sulfonate solution. The temperature is raised and stirred for reaction. After cooling, ice water is added for precipitation to obtain a product. The product is washed with ice water and vacuum dried to obtain modified sodium naphthalene sulfonate.

7. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 6, characterized in that: The mass ratio of the sodium naphthalenesulfonate body, ammonium persulfate and cetylpyridinium chloride is 1:0.05:(0.02-0.08).

8. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 1, characterized in that: The dislodging agent comprises carboxyethyl isothiourea chloride, sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole.

9. The environmentally friendly cyanide-free zincate zinc plating brightener according to claim 8, characterized in that: The mass ratio of the carboxyethyl isothiourea chloride, sodium hydroxymethyl sulfonate and 2-mercaptobenzimidazole is (0.02-0.05):1:0.

5.

10. A method for preparing an environmentally friendly cyanide-free zincate zinc plating brightener as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: The sulfonic acid modified p-chlorobenzylideneacetone is added to ethylene glycol monobutyl ether under water bath heating conditions. After stirring evenly, the conjugated modified anisaldehyde, isomeric tridecanol polyoxyethylene ether, polyethylene glycol, compound auxiliary brightener and moving agent are added in sequence. Stirring is performed after each ingredient is added. After the addition is completed, the speed is increased and stirring is continued to obtain an environmentally friendly cyanide-free zincate zinc plating brightener.

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