Brightener for PSA electrotinning insoluble anode system and application

Abstract

The invention discloses a brightener for a PSA electrotinning insoluble anode system and application. The brightener comprises a main brightening agent, a dispersing agent, an antioxidant and a complexing agent; the main brightening agent comprises imidazoline and 3-alkyl-4-amino-5-mercapto-1, 2, 4-s-triazole; and the dispersing agent comprises polyethylene glycol and alkyl amide polyoxyethylene ether. According to the brightener for the PSA electrotinning insoluble anode system, a plating solution can be stable, no strong pungent smell exists during electroplating, high-current-density tinning can be allowed, and the brightener is suitable for continuous and rapid tinning of plates, strips and wires; and when 3%-5% of the brightener is added into the electroplating solution of the PSA electrotinning insoluble anode system for electroplating, plating grains are uniform and refined, a plating is bright, tin ions in the electroplating solution are not prone to being oxidized, and the corrosion resistance of the plating is excellent.

Description

technical field [0001] The invention relates to the field of additives in the tin plating process, in particular to a brightener for PSA electroplating tin insoluble anode system and its application. Background technique [0002] The surface of the electroplated tin plate generally has an oil coating layer, a passivation layer, a tin oxide layer, a pure tin coating layer and an iron-tin alloy layer (FeSn 2 ), etc., so the electroplated tinplate has excellent corrosion resistance to dilute acid, alkali, salt and organic substances, as well as excellent weldability, punchability and strength, and is easy to coat and print; therefore, the electroplated tinplate is widely used in various Form articles such as chemicals, paints, sprays, food, beverage packaging and the manufacture of various utensils. [0003] For a long time, the electroplating and coating properties of electroplated tinplate have been a special concern of manufacturers; extensive and in-depth research has been...

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Problems solved by technology

[0003] For a long time, the electroplating and coating properties of electroplated tinplate have been a special concern of manufacturers; extensive and in-depth research has been conducted internationally on various factors that affect the electroplating and coating properties of tinplate, but they keep the relevant research results confidential , while the domestic production of tinplate started relatively late, and the technology was imported from abroad; the existing high-speed electroplating tin plating production line mainly adopts the Ferrostan stannous sulfate method, and the plating solution is mainly composed of stannous sulfate, PSA (phenol sulfonic acid), additive EN-10 (α-naphthol polyoxyethylene ether, ethoxy average polymerization degree NEO=10) and ENSA (α-naphthol sulfonic acid polyoxyethylene ether, ethoxy average polymerization degree NEO=6, which contains about 40% unsulfonated EN-6); but after a period of production and operation of the high-speed tinning unit, oil stains often appear on the dead corners of the plating solution, and this oil floating on the surface of the plating solution It is easy to adhere to the surface of the steel plate, causing stains on the surface of the tinplate (the probability of occurrence is about 0.2-0.4%); due to the Sn in the tin plating solution 2+ Unstable and easy to generate Sn 4+ , while Sn 4+ It can still be hydrolyzed to generate β-stannoic acid SnO 2 2H 2 O, and then coalesce into β-stannic acid, that is, tin mud; as its concentration increases, the plating solution becomes more and more turbid, and the viscosity becomes larger and larger, and the amount of solution carried out due to the viscosity of the plating solution increases, and the loss increases Large, making complex workpieces difficult to clean; during electrodeposition, these Sn 4+ The jelly will follow the Sn 2+ The ions are deposited into the coating together, affecting the stability of the plating solution, causing the coating to become discolored, brittle, and the surface of the coating to be rough; in the actual production process, the Sn 4+ content to achieve the purpose of reducing tin mud to ensure the performance of the plating solution and the quality of the coating; Sn 4+ The content of tin is mainly controlled from three factors: bath temperature, anode current density, and sulfuric acid content: (1) Strictly control the bath temperature. The optimum plating temperature for acidic tin plating is generally around 20°C, preferably not exceeding 25°C. Too low, poor conductivity, small allowable current, slow deposition rate, too high temperature, especially during high-current electroplating, the temperature of the local area of ​​the anode will rise, and Sn is easy to form 4+ ;(2) Strictly control the anode current density. Excessively high current density will cause the anode to passivate and blacken, resulting in the obstruction of normal dissolution. Too high or too low anode current density is unfavorable; (3) Regular analysis and adjustment control during production Sulfuric acid content to prevent Sn 2+ hydrolysis

Despite strict control, sometimes due to factors such as weather, refrigeration equipment, electroplating products, etc., it is inevitable that the plating solution will be cloudy and produce tin mud, especially in the hotter southern regions, this phenomenon is more serious