A general acid-base water-based zinc plating additive and its application

Abstract

The present invention relates to a universal acid-base water-based zinc plating additive and its application. The universal acid-base water-based zinc plating additive comprises 5wt.% to 20wt.% of polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine, 5wt.% to 10wt.% of trigonelline, 1wt.% to 5wt.% of compound A, 2wt.% to 8wt.% of sodium benzoate, 5wt.% to 10wt.% of tetrahydroxypropylethylenediamine, 0.5wt.% to 5wt.% of glucuronolactone, and the balance is water; wherein compound A is a reactant of nicotinic acid and propane sultone. The universal acid-base water-based zinc plating additive can be used in three production lines: alkaline zinc plating, sulfate zinc plating, and potassium chloride zinc plating. The organic pollutants in the wastewater of the three production lines can be made the same, facilitating unified treatment.

Description

Technical Field

[0001] The invention belongs to metal corrosion protection and surface treatment technology, and particularly relates to an acid-base universal water-based zinc plating additive and application thereof. Background Art

[0002] Currently, most electroplating companies implement centralized production and management within industrial parks. The centralized disposal of pollutants following the concentration of various electroplating production lines has complicated previously single wastewater treatment issues. Regarding the zinc plating process, which accounts for the largest share, acid and alkaline zinc plating each has its own advantages and uses different additives. For example, Chinese patent CN1087791C discloses a brightener for sulfate zinc plating consisting of a primary brightener, benzyl acetone; a carrier brightener, alkylphenol polyoxyethylene ether; methyl and propyl aniline as brighteners; and a dispersant, naphthyl sulfonate. Chinese patent CN104164686A discloses an acidic zinc plating bath additive that uses 10-90% long-chain alkane benzene sulfonate and / or a heterocyclic organic amine. Chinese patent CN10325549A discloses a highly dispersible alkaline zinc plating additive whose component A consists of BPC-48, DPE-III, H1, polyamine sulfone, IME, and EDTA-2Na, and component B consists of WT. In general, the additives for alkaline zinc plating are simple in composition and have good coating adhesion. The zinc plating layer has a columnar structure, strong corrosion resistance, good passivation film adhesion, and is not easy to discolor. Its additives are mostly DE / DPE type additives modified by organic amines, and the brightener is benzylpyridinium-3-carboxylate; the coating of acidic zinc plating additives is bright, the plating speed is fast, the efficiency is high, and the cost is low. Although the main salts of sulfate and chloride zinc plating are different, the additives belong to the same system. They all use benzyl acetone as the main brightener to refine the crystallization, use non-ionic surfactants or anionic surfactants sulfonated with aminosulfonic acid as carrier brighteners to solubilize the main brightener, and use diffusing agents NNO, sodium benzoate, etc. as auxiliary brighteners. It can be seen that the pollutants in the wastewater discharged by different galvanizing production lines are not the same. The alkaline galvanizing additives are mainly derivatives of organic amines, while the weakly acidic galvanizing additives are rich in surfactants and oil-soluble organic compounds. After the acid and base pollutants are mixed, physical and chemical reactions such as emulsification and neutralization to form salts may occur, which will increase the soluble substances in the wastewater. Additional demulsification, neutralization and other agents need to be added during the treatment process. Even the aldehyde organic matter in the additives will cause the death of microorganisms in the sludge. All of the above factors have brought great challenges to the wastewater treatment of electroplating parks. If the organic components of acidic galvanizing and alkaline galvanizing additives can be unified, it will greatly alleviate the difficulties faced by the centralized disposal of pollutants in electroplating parks.

[0003] Although the existing polymer DPE-I of dimethylaminopropylamine and epichlorohydrin can be used in alkaline zinc plating and sulfate zinc plating production lines, experiments have shown that when DPE-I is used in a weakly acidic potassium chloride zinc plating production line, the current efficiency is significantly reduced, there is no adsorption or little adsorption in the low current density area, and there is no coating in the low current density area; when used in sulfate zinc plating, zinc is only deposited in the middle area of ​​the cathode plate. Summary of the Invention

[0004] The invention aims to provide a water-based zinc plating additive that can be used in three production lines: alkaline zinc plating, sulfate zinc plating, and potassium chloride zinc plating, so that the organic pollutants in the wastewater of the three production lines are the same, which is convenient for unified treatment.

[0005] The present invention achieves the purpose of the invention through the following technical solutions:

[0006] The present invention provides a universal acid-base water-based zinc plating additive, comprising 5 wt.% to 20 wt.% of polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine, 5 wt.% to 10 wt.% of trigonelline, 1 wt.% to 5 wt.% of compound A, 2 wt.% to 8 wt.% of sodium benzoate, 5 wt.% to 10 wt.% of tetrahydroxypropylethylenediamine, 0.5 wt.% to 5 wt.% of glucuronolactone, and the balance being water; wherein the structural formula of compound A is:

[0007]

[0008] In some specific embodiments, the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine is prepared by reacting epichlorohydrin with an organic amine at an equivalent ratio of 1 to 1.05:1; the organic amine is composed of a nitrogen-containing heterocyclic compound and a chain amine.

[0009] In some specific embodiments, the organic amine is composed of a nitrogen-containing heterocyclic compound and a chain amine in a molar ratio of 1:4.

[0010] In some specific embodiments, the nitrogen-containing heterocyclic compound is one or more of thiazole, imidazole, pyrimidine, and 4-methylimidazole.

[0011] In some embodiments, the chain amine contains at least one tertiary amine group and one hydroxyl group or primary amine group.

[0012] In some specific embodiments, the chain amine is at least one of N,N-dimethylethanolamine, N,N-diethylethanolamine, and N,N-dimethylaminopropylamine.

[0013] In some specific embodiments, the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine is prepared by the following method: controlling the temperature of the organic amine to not exceed 7°C, slowly adding epichlorohydrin to ensure that the solution temperature does not exceed 25°C during the addition process, and controlling the solution temperature to 30±5°C after the addition is completed for reaction to obtain the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine.

[0014] In some specific embodiments, compound A is prepared by the following method: heating a nicotinic acid aqueous dispersion to reflux and adding sodium carbonate until the solution is clarified; after the addition is completed, cooling to 80±5°C, adding molten propane sultone dropwise, continuing to reflux until the reaction is completed, and finally adjusting the pH to 6.3±0.2 to obtain compound A, the reaction formula is:

[0015]

[0016] In some specific embodiments, the concentrations of the substances in the acid-base universal zinc plating brightener solution are: polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine 12 wt.%, trigonelline 5 wt.%, compound A 2.5 wt.%, sodium benzoate 3 wt.%, tetrahydroxypropyl ethylenediamine 5 wt.%, and glucuronolactone 5 wt.%.

[0017] The present invention also provides the use of an acid-base universal water-based zinc plating additive in a zinc plating process, wherein the acid-base universal water-based zinc plating additive is the only organic component in the zinc plating electrolyte.

[0018] In some specific embodiments, the amount of the acid-base universal water-based zinc plating additive added to the sulfate zinc plating electrolyte is 16-20 mL / L, the amount added to the potassium chloride zinc plating electrolyte is 20-25 mL / L, and the amount added to the alkaline zincate zinc plating electrolyte is 8-16 mL / L.

[0019] Compared with the prior art, the technical solution provided by the present invention has the following advantages and beneficial effects

[0020] The acid-base universal water-based zinc plating additive provided by the present invention can be used in three production lines: alkaline zinc plating, sulfate zinc plating, and potassium chloride zinc plating. It can make the organic pollutants in the wastewater of the three production lines the same, which is convenient for unified treatment.

[0021] The present invention provides an acid-base universal water-based zinc plating additive that does not contain aromatic aldehydes and ketones and surfactants, the working fluid does not generate foam, the wastewater has low COD, is easy to handle, does not require additional treatment steps, has low reagent consumption, and is compatible with traditional weakly acidic sulfate zinc plating additives. It can be directly replaced and supplemented until the original additive is completely consumed, without the need for re-tank preparation. Therefore, it is an efficient and environmentally friendly zinc plating additive. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 Table 1 is the SEM (JEOL JEM-2100F) of the cathode specimen in alkaline zincate zinc plating;

[0024] Figure 1 (a) shows the morphology of Zn crystals formed in the absence of an acid-base universal water-based zinc plating additive. The Zn grains are granular, and mixed diffusion and activation control occur during the electrodeposition process.

[0025] Figure 1 (b) and Figure 1 (c) shows the surface morphology when the lower limit and upper limit of the acid-base universal water-based zinc plating additive are added, respectively. The Zn crystals are densely arranged and appear to be mirror-bright on a macroscopic scale.

[0026] Figure 2 Table 1 is the SEM (JEOL JEM-2100F) of the cathode specimen in the acidic potassium chloride zinc plating; wherein:

[0027] Figure 2 (a) shows the Zn crystal morphology formed when no acid-base universal water-based zinc plating additive is used. In the potassium salt solution, the Zn crystals are deposited in a needle-like structure.

[0028] Figure 2 (b) shows the surface morphology when the upper limit of the acid-base universal water-based zinc plating additive is added. The crystal arrangement is denser than when there is no additive, but it is still loose and has voids. The macroscopic appearance is matte, and sealing treatment is required later.

[0029] Figure 3 Table 1 is the SEM (Zeiss Gemini 500) of the cathode specimen in sulfate zinc plating;

[0030] Figure 3 (a) shows the Zn crystal morphology formed in the absence of the acid-base universal water-based zinc plating additive. Similar to zincates, the Zn crystal structure is granular, but it can also show a hexagonal flake morphology. Due to the competitive inhibition of the acid-base universal water-based zinc plating additive, the crystals tend to be flake-like.

[0031] Figure 3 (b) shows the apparent morphology of the acid-base universal water-based zinc plating additive at the upper limit of addition. The crystals are closely arranged in flaky form, with trace inclusions of metallic aluminum. The actual coating is a uniform white with a metallic luster.

[0032] Figure 4 The zinc plating results of the alkaline zincate zinc plating electrolyte prepared by replacing the acid-base universal water-based zinc plating additive with the comparative zinc plating additive 1 are shown; Figure 4 (A) is the zinc plating result of the acid-base universal water-based zinc plating additive prepared by the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 1 in the alkaline zincate zinc plating electrolyte; Figure 4 (B) is the comparative zinc plating results using zinc plating additive 1 in alkaline zincate zinc plating electrolyte.

[0033] Figure 5 The zinc plating results of potassium chloride zinc plating electrolyte prepared by replacing acid-base universal water-based zinc plating additive with comparative zinc plating additive 1 are shown; Figure 5 (A) Application effect of an acid-base universal water-based zinc plating additive prepared from a polyepichlorohydrin-nitrogen-containing heterocycle-chain amine aqueous solution 1 in a potassium chloride electrolyte; Figure 5 (B) is the comparative effect of using zinc plating additive 1 in potassium chloride electrolyte.

[0034] Figure 6 The application effect of the acid-base universal water-based zinc plating additive prepared from the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution prepared in different synthesis experiments of Example 1 in the alkaline zincate zinc plating electrolyte is demonstrated; Figure 6 (A) The application effect of the acid-base universal water-based zinc plating additive prepared by polyepichlorohydrin-nitrogen-containing heterocycle-chain amine aqueous solution 4 in the alkaline zincate zinc plating electrolyte; Figure 6 (B) is the application effect of the acid-base universal water-based zinc plating additive prepared from the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 1 in the alkaline zincate zinc plating electrolyte.

[0035] Figure 7 The application effect of the acid-base universal water-based zinc plating additive prepared from the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution prepared in different synthesis experiments of Example 1 in the alkaline zincate zinc plating electrolyte is demonstrated; Figure 7 (A) The application effect of the acid-base universal water-based zinc plating additive prepared by polyepichlorohydrin-nitrogen-containing heterocycle-chain amine aqueous solution 2 in the alkaline zincate zinc plating electrolyte; Figure 7 (B) is the application effect of the acid-base universal water-based zinc plating additive prepared from the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 3 in the alkaline zincate zinc plating electrolyte. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0037] The present invention provides a universal acid-base water-based zinc plating additive, comprising 5 wt.% to 20 wt.% of polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine, 5 wt.% to 10 wt.% of trigonelline, 1 wt.% to 5 wt.% of compound A, 2 wt.% to 8 wt.% of sodium benzoate, 5 wt.% to 10 wt.% of tetrahydroxypropylethylenediamine, 0.5 wt.% to 5 wt.% of glucuronolactone, and the balance being water; wherein the structural formula of compound A is:

[0038]

[0039] In the acid-base universal water-based zinc plating additive provided by the present invention, polyepichlorohydrin-nitrogen-containing heterocycle-chain amine is a polarizing additive, which functions to increase cathode polarization, inhibit the discharge of zinc ions, and refine crystals. Compared with DPE-I, polyepichlorohydrin-nitrogen-containing heterocycle-chain amine has a nitrogen-containing heterocyclic compound added to its structure, and has better cathode adsorption and dispersion properties for zinc ions. Compound A in the acid-base universal water-based zinc plating additive is used as a leveling agent and low-zone moving agent in a weakly acidic zinc plating production line, and plays a role in refining crystals in an alkaline zinc plating production line.

[0040] In some specific embodiments, the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine is formed by reacting epichlorohydrin with an organic amine in an equivalent ratio of 1 to 1.05:1; the organic amine is composed of a nitrogen-containing heterocyclic compound and a chain amine. A higher organic amine content results in a higher quaternary ammonium cation content, a higher allowable current density in the high current density range, and improved brightness of the coating. Conversely, a lower organic amine content and a lower quaternary ammonium cation content result in the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine failing to expand the bright current density range and enhance the brightness of the coating.

[0041] In some specific embodiments, the organic amine comprises a nitrogen-containing heterocyclic compound and a chain amine in a molar ratio of 1:4. Increasing the proportion of the nitrogen-containing heterocyclic compound significantly increases the brittleness of the coating, and the coating may even fall off when the test piece is bent. The applicant's analysis suggests that increasing the nitrogen-containing heterocyclic compound content may result in the nitrogen-containing heterocyclic compound not fully participating in the reaction, or incomplete N-quaternization, leading to competitive adsorption of the nitrogen-containing heterocyclic compound on the cathode surface or inclusion in the coating, resulting in an increase in the carbon content of the coating and thus increased brittleness.

[0042] In some specific embodiments, the nitrogen-containing heterocyclic compound is one or more of thiazole, imidazole, pyrimidine, and 4-methylimidazole.

[0043] In some specific embodiments, the chain amine is at least one of N,N-dimethylethanolamine, N,N-diethylethanolamine, and N,N-dimethylaminopropylamine. The alcohol amine can increase the hydrophilic group of the compound, reduce the adsorption strength of the compound, and reduce the discoloration and brittleness of the coating.

[0044] In some specific embodiments, the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine is prepared by the following method: controlling the temperature of the organic amine to not exceed 7°C, slowly adding epichlorohydrin to ensure that the solution temperature does not exceed 25°C during the addition process, and controlling the solution temperature to 30±5°C after the addition is completed for reaction to obtain the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine. Specifically, the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine is prepared by the following method: adding an organic amine to a reactor at an equivalent weight of 1, adding deionized water, releasing heat when the organic amine dissolves, starting stirring, and passing 5°C chilled water into the reactor coil to cool the organic amine solution in the reactor; at the same time, pumping 1.03 equivalents of epichlorohydrin into the feeding kettle for standby use; when the temperature of the organic amine solution drops to 7°C, turning on the shielded pump under the epichlorohydrin feeding kettle, controlling the feeding rate through the flow temperature transmitter of the shielded pump to ensure that the temperature in the kettle does not exceed 25°C; after the addition of epichlorohydrin, passing circulating water into the reactor coil to raise the system temperature to about 30°C, continuing the reaction with insulation and stirring for 3 hours, and then adding sufficient deionized water to adjust the product content to 45wt.%. The polymerization reaction of epichlorohydrin, nitrogen-containing heterocyclic compounds, and chain amines is an exothermic reaction. The temperature of the organic amine is controlled at around 7°C in the early stage. The temperature is relatively easy to control when epichlorohydrin is subsequently added. As the reaction proceeds, the material becomes viscous and the feedback of the thermocouple lags. Once a large amount of polymerization heat accumulates, the material will explode to form a gel-like water-insoluble polymer. The reaction temperature is controlled at around 30°C to control the epichlorohydrin to first open its ring and react with primary amines, and then react with secondary and tertiary amines to form quaternary ammonium reactions.

[0045] In some specific embodiments, Compound A is prepared by the following method: heating a nicotinic acid aqueous dispersion to reflux, adding sodium carbonate to neutralize the nicotinic acid to promote dissolution of the nicotinic acid, cooling the solution to 80±5°C after clarification, adding molten propane sultone dropwise, continuing to reflux until the reaction is complete, and finally adjusting the pH to 6.3±0.2 to obtain Compound A. The synthesis method of Compound A is as follows: 1 mol of nicotinic acid is added to a reactor, followed by addition of water twice the mass of the nicotinic acid, and the temperature is raised to reflux with stirring. The nicotinic acid is not completely dissolved, and the material becomes a white slurry. Sodium carbonate solution is slowly added to the reactor under reflux, and a large amount of foaming will be generated after the addition. After the bubbles disappear, the solution is added again until all the addition is complete. With the addition of sodium carbonate, the solution gradually becomes clear and transparent and turns light yellow. After all the sodium carbonate is added, wait for all the bubbles to disappear, reflux for 1 hour, then cool to 80°C, add 1 mol of melted propane sultone dropwise, keep warm for 30 minutes after addition, then heat to reflux again, keep reflux for 4 hours, cool, adjust the pH value of the solution to about 6.5, cool, and dilute the product concentration with water to a 40wt.% solution.

[0046] Preferably, the concentrations of the various substances in the acid-base universal zinc plating additive are: 12 wt.% of polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine, 5 wt.% of trigonelline, 2.5 wt.% of compound A, 3 wt.% of sodium benzoate, 5 wt.% of tetrahydroxypropylethylenediamine, and 5 wt.% of glucuronolide. In the acid-base universal zinc plating additive provided by the present invention, trigonelline acts as a brightener and dispersant, has good depth capability, and reduces the brittleness of the coating after use; the use of sodium benzoate improves the positioning of the low-lying area; and tetrahydroxypropylethylenediamine and glucuronolide act as complexing agents, forming complex ions with zinc ions to change the electrode reaction rate of hydrated metal ions, making it more difficult for the complex to dissociate the ligand to form an activated complex. That is, the activation energy during metal ion reduction is higher, and the overvoltage is larger. Correspondingly, the electrode reaction rate is reduced, the exchange current density is reduced, and it is easier to obtain a fine coating.

[0047] Preferably, the preparation method of the acid-base universal zinc plating additive is as follows: first, glucuronolide and sodium benzoate are added to a reactor, 1 / 4 of the total volume of water is added to the reactor, stirring is started, the temperature is raised to 45°C, and slowly stirred in the dark until glucuronolide and sodium benzoate are completely dissolved, and then trigonelline is slowly added to the reactor, slightly exothermic, and the temperature is controlled not to exceed 50°C by a refrigerant, and then polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine and compound A are added to the reactor, the temperature is controlled below 45°C, and stirred evenly, and finally tetrahydroxypropyl ethylenediamine is added and deionized water is added to the total volume, the mixture is kept warm and stirred for 1 hour, and the mixture is discharged after cooling to room temperature.

[0048] The present invention also provides the use of an acid-base universal water-based zinc plating additive in a zinc plating process, wherein the acid-base universal water-based zinc plating additive is the only organic component in the zinc plating electrolyte.

[0049] In some specific embodiments, the amount of the acid-base universal water-based zinc plating additive added to the sulfate zinc plating electrolyte is 16-20 mL / L, the amount added to the potassium chloride zinc plating electrolyte is 20-25 mL / L, and the amount added to the alkaline zincate zinc plating electrolyte is 8-16 mL / L.

[0050] The technical solution of the present invention is described in detail below through specific embodiments:

[0051] Example 1

[0052] Synthesis experiment 1: Weigh 82g (0.80mol) of N,N-dimethylaminopropylamine and 14g (0.20mol) of imidazole into a reactor, add 200g of deionized water, start stirring, and exotherm occurs. Cool the reactor with an ice water bath; at the same time, add 96g (1.04mol) of epichlorohydrin into a constant pressure dropping funnel for later use; when the temperature of the solution in the reactor drops to 7°C, add epichlorohydrin dropwise to the reactor, controlling the feeding rate. The reaction mixture was stirred at room temperature for 3 hours to produce polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine. 220 g of deionized water was then added to the reaction solution to adjust the content of the product polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine to about 45 wt. %, thereby obtaining a polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 1.

[0053] Synthesis Experiment 2: The same as Synthesis Experiment 1, except that 0.50 mol N,N-dimethylaminopropylamine and 0.50 mol imidazole were added to the reactor. The resulting product was insoluble in water.

[0054] Synthesis Experiment 3: Essentially identical to Synthesis Experiment 1, except that 0.66 mol of N,N-dimethylaminopropylamine and 0.33 mol of imidazole were added to the reactor. The resulting product was an opaque white liquid. It could replace the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution and was dissolved in the alkaline zincate zinc plating electrolyte listed in Table 1. However, the resulting coating was brittle. The resulting product was insoluble in the sulfate zinc plating electrolyte and potassium chloride zinc plating electrolyte listed in Table 1.

[0055] Synthesis Experiment 4: It is basically the same as Synthesis Experiment 1, except that imidazole is replaced by pyrimidine to obtain polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 2.

[0056] Synthesis Experiment 5: It is basically the same as Synthesis Experiment 1, except that imidazole is replaced by 4-methylimidazole to obtain polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 3.

[0057] Synthesis Experiment 6: It is basically the same as Synthesis Experiment 1, except that imidazole is replaced by thiazole to obtain polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 4.

[0058] Example 2

[0059] 123 g (1.00 mol) of nicotinic acid was added to a reactor, followed by 250 g of deionized water. The mixture was heated to reflux with stirring until the material became a white slurry. Saturated sodium carbonate solution was slowly added to the reactor under reflux to neutralize the nicotinic acid and promote its dissolution. A large amount of foaming was generated after the addition of saturated sodium carbonate solution. After the bubbles disappeared, saturated sodium carbonate solution was added again until the solution gradually became clear and transparent, at which point the solution was light yellow. After all bubbles disappeared, the mixture was refluxed for 1 hour, then cooled to 80° C., and 120 g (0.98 mol) of melted propane sultone was added dropwise. After the addition was complete, the mixture was incubated for 30 minutes, then heated to reflux again. After reflux for 4 hours, the temperature was lowered, the pH of the solution was adjusted to about 6.5, cooled, and diluted with water to a concentration of 40 wt.% of Compound A to obtain an aqueous solution of Compound A.

[0060] Example 3

[0061] In this example, the concentrations of the substances in the preformulated acid-base universal zinc plating additive are as follows: 5 wt.% of glucuronolide, 3 wt.% of sodium benzoate, 5 wt.% of trigonelline, 12 wt.% of polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine, 2.5 wt.% of compound A, and 5 wt.% of tetrahydroxypropylethylenediamine, with a total volume of 1000 mL. The amounts of each substance to be added are calculated based on the concentrations and total volume of the preformulated acid-base universal zinc plating additive, and each substance is measured.

[0062] First, glucuronolide and sodium benzoate were added to the reactor, 1 / 4 of the total volume of water was added to the reactor, stirring was started, the temperature was raised to 45 ° C, and the glucuronolide and sodium benzoate were slowly stirred in the dark until they were completely dissolved. Then, trigonelline was slowly added to the reactor, slightly exothermic, and the temperature was controlled not to exceed 50 ° C by the refrigerant. Then, the polyepichlorohydrin-nitrogen-containing heterocycle-chain amine aqueous solution obtained in Example 1 and the compound A aqueous solution obtained in Example 2 were added to the reactor, the temperature was controlled below 45 ° C, tetrahydroxypropylethylenediamine was added after stirring, and deionized water was added to the total volume. After keeping warm and stirring for 1 hour, it was cooled to room temperature and discharged to obtain an acid-base universal zinc plating additive.

[0063] Example 4: Hull cell experiment and performance test

[0064] Hull Cell Test: A brass sheet (6cm x 10cm x 2mm) polished to a mirror finish with a cloth wheel was used as the cathode test piece. The Hull Cell was placed in a constant-temperature water bath (20-40°C), with an electrolytic zinc plate (iron plate for alkaline galvanizing) as the anode. The test was conducted at a constant current density. No anode treatment was required. The cathode test piece pretreatment process was as follows: degreasing with alkaline solution → rinsing with hot water → rinsing with tap water → acid cleaning and activation → rinsing with tap water → rinsing with tap water → potassium chloride zinc plating / sulfate zinc plating / alkaline zincate zinc plating → rinsing with tap water → drying → performance testing.

[0065] Refer to the following method to perform performance testing:

[0066] The dispersion performance of the plating solution is tested using the near-far cathode method of JB / T7704.4, with the K value set at 3;

[0067] The current efficiency of the plating solution is tested using the copper coulometer method of JB / T 7704.3. In the present invention, the electrochemical equivalent of zinc is 1.220 g / (A·h);

[0068] The process conditions and electrochemical test results of the acid-base universal water-based zinc plating additive prepared from the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine aqueous solution 1 obtained in Example 3 are shown in Table 1:

[0069] Table 1 Process conditions and electrochemical test results of acid-base universal water-based zinc plating additives

[0070]

[0071]

[0072] Note: According to the standard of JB / T 10339, the current efficiency of alkaline zincate zinc plating is ≥75%, the current efficiency of sulfate zinc plating is ≥95%, and the current efficiency of potassium chloride zinc plating is ≥95%.

[0073] The electrochemical test results shown in Table 1 show that, for the three electrolytes to which the acid-base universal water-based zinc plating additive is added, except for the current efficiency of the potassium chloride zinc plating electrolyte being slightly lower than 95%, the other indicators all meet the technical requirements, indicating that the acid-base universal water-based zinc plating additive prepared in Example 3 of the present invention can meet the requirements for universal acid-base zinc plating.

[0074] The polyepichlorohydrin-nitrogen-containing heterocycle-chain amine aqueous solution obtained in Experiments 4 to 6 of Example 1 was prepared into an acid-base universal aqueous zinc plating additive according to the method of Example 3 and applied to the alkaline zincate zinc plating electrolyte shown in Table 1. The results are as follows: Figure 6 、 Figure 7 As shown, the actual usage effect is: Synthesis Experiment 4 (pyrimidine)>Synthesis Experiment 1 (imidazole)>Synthesis Experiment 5 (4-methylimidazole)>Synthesis Experiment 6 (thiazole).

[0075] Comparative Example 1

[0076] 102g (1.00mol) of N,N-dimethylaminopropylamine was weighed and put into the reactor, 200g of deionized water was added, stirring was started, there was an exothermic phenomenon, and the reactor was cooled with an ice-water bath; at the same time, 96g (1.04mol) of epichlorohydrin was added to the constant pressure dropping funnel for standby use; when the temperature of the solution in the reactor was reduced to 7°C, epichlorohydrin was added dropwise to the reactor, the feeding rate was controlled to ensure that the temperature in the reactor did not exceed 25°C, after the addition of epichlorohydrin, the ice-water mixture was removed, the temperature was naturally raised, the system temperature was raised to about 30°C, and the reaction was continued with stirring for 3 hours to generate polyepichlorohydrin-chain amine; 220g of deionized water was then added to the reaction solution, and the content of the product polyepichlorohydrin-chain amine was adjusted to about 45wt.%, to obtain a polyepichlorohydrin-chain amine aqueous solution, i.e. DPE-I.

[0077] A zinc plating additive was prepared according to the method of Example 3, except that a polyepichlorohydrin-chain amine aqueous solution was used instead of the polyepichlorohydrin-nitrogen-containing heterocycle-chain amine aqueous solution in Example 3 to obtain a comparative zinc plating additive 1.

[0078] The alkaline zincate zinc plating electrolyte was prepared according to the formula of Example 4, except that the comparative zinc plating additive 1 was used instead of the acid-base universal water-based zinc plating additive. The results are as follows: Figure 4 As shown, when zinc is plated with the alkaline zincate zinc plating electrolyte prepared with comparative zinc plating additive 1, a fault appears in the middle area of ​​the test piece, and the middle and low areas turn black, indicating that the middle and low areas have less adsorption.

[0079] The potassium chloride zinc plating electrolyte was prepared according to the formula of Example 4, except that the acid-base universal water-based zinc plating additive 1 was used instead of the comparative zinc plating additive. The results are as follows: Figure 5 As shown, when zinc plating is carried out using the potassium chloride zinc plating electrolyte prepared with the comparative zinc plating additive 1, only about 2 cm of coating is formed in the high area, the coating in the middle area is thinner and gray, and there is leakage plating in the low area and no coating.

[0080] The present invention illustrates the performance and electroplating process of the acid-base universal water-based zinc plating additive through the above embodiments, but does not limit the present invention to this, nor does it mean that the present invention must rely on the compound composition and addition amount in the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A universal acid and alkali water-based zinc plating additive, characterized by: The invention comprises 5wt.% to 20wt.% of polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine, 5wt.% to 10wt.% of trigonelline, 1wt.% to 5wt.% of compound A, 2wt.% to 8wt.% of sodium benzoate, 5wt.% to 10wt.% of tetrahydroxypropylethylenediamine, 0.5wt.% to 5wt.% of glucuronolactone, and the balance being water; wherein the structural formula of compound A is: ； The polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine is prepared by reacting epichlorohydrin with an organic amine at an equivalent ratio of 1 to 1.05:1; the organic amine is composed of a nitrogen-containing heterocyclic compound and a chain amine; The organic amine is composed of a nitrogen-containing heterocyclic compound and a chain amine in a molar ratio of 1:4; The nitrogen-containing heterocyclic compound is one or more of thiazole, imidazole, pyrimidine, and 4-methylimidazole; The chain amine is at least one of N,N-dimethylethanolamine, N,N-diethylethanolamine, and N,N-dimethylaminopropylamine.

2. The acid-base universal water-based zinc plating additive according to claim 1, characterized in that: The polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine is prepared by the following method: controlling the temperature of the organic amine to not exceed 7°C, slowly adding epichlorohydrin to ensure that the solution temperature does not exceed 25°C during the addition process, and controlling the solution temperature to 30±5°C after the addition is completed to carry out the reaction, thereby obtaining the polyepichlorohydrin-nitrogen-containing heterocyclic-chain amine.

3. The acid-base universal water-based zinc plating additive according to claim 1, characterized in that: The compound A is prepared by the following method: heating a nicotinic acid aqueous dispersion to reflux and adding sodium carbonate until the solution is clarified; after the addition is completed, cooling to 80±5°C, adding molten propane sultone dropwise, continuing to reflux until the reaction is completed, and finally adjusting the pH value to 6.3±0.2 to obtain compound A.

4. Use of the acid-base universal water-based zinc plating additive according to any one of claims 1 to 3 in a zinc plating process, characterized in that: The acid-base universal water-based zinc plating additive is the only organic component in the zinc plating electrolyte.

5. The use according to claim 4, characterized in that: The amount of the acid-base universal water-based zinc plating additive added to the sulfate zinc plating electrolyte is 16-20 mL / L, the amount added to the potassium chloride zinc plating electrolyte is 20-25 mL / L, and the amount added to the alkaline zincate zinc plating electrolyte is 8-16 mL / L.

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