Antioxidant for tin methanesulfonate plating and preparation method thereof

Abstract

The invention belongs to the technical field of steel plate tin plating, and particularly discloses an antioxidant for methanesulfonic acid tin plating and a preparation method thereof, and the antioxidant comprises the following components by weight: 1-10 parts of 8-hydroxyquinoline sulfonate, 1-10 parts of citrate, 5-10 parts of methanesulfonic acid, 0.1-1 part of benzenediol, and the balance of deionized water. The preparation method comprises the following steps: (1) dissolving 8-hydroxyquinoline sulfonate in deionized water to prepare a solution A; (2) weighing a proper amount of methanesulfonic acid and citrate, and adding the methanesulfonic acid and citrate into the solution A to prepare a solution B; (3) weighing a small amount of benzenediol, and adding the benzenediol into the solution B to prepare a solution C; and (4) heating the solution C to 55-65 DEG C, and continuously stirring to obtain the antioxidant after the substances are completely dissolved. The antioxidant effectively inhibits oxidation of divalent tin ions in the methanesulfonic acid tin plating solution, and reduces oxidation of tin, so that generation of tin oxide and tin sludge is inhibited.

Description

Technical Field

[0001] The invention belongs to the technical field of tin-plating of steel plates, and relates to a treating agent for steel plates and a preparation method thereof, and specifically relates to a treating agent for methanesulfonic acid tin-plated steel plates and a preparation method thereof. Background Art

[0002] Tinplate, commonly known as tinplate, is a cold-rolled thin steel plate with a double-sided electroplated tin layer, mostly used to make food cans and beverage cans. There are two commonly used production processes for electroplated tin steel strips: one is the phenolsulfonic acid (PSA) plating solution system, which is used in most tinning lines; the other is a halide-based plating solution system. As the electroplating tin industry pays more attention to environmental protection, the production process of electroplated tin steel strips has undergone tremendous changes. A methylsulfonate (MSA) tinning process with special additives has developed rapidly. In recent years, domestic tinplate manufacturers have gradually adopted this more environmentally friendly process to replace the PSA process. As the users of tinplates have increasing requirements for low costs, products are gradually developing towards low tin plating amounts, 1.1g / m 2 There are more and more thin tinplate products with even lower tin plating amount.

[0003] Antioxidant is one of the additives that must be added to the MSA tin plating system. Its main function is to improve the stability of the plating solution and inhibit the formation of Sn in the plating solution. 2+ Oxidized to Sn 4+ Common antioxidants include hydroquinone, resorcinol, ascorbic acid, β-quinolinephenol, phenolsulfonic acid, vanadium pentoxide and its reduction products.

[0004] A Chinese patent document entitled "A tin plating additive and its preparation method" with publication number CN 109666954 A and publication date April 23, 2019 discloses a tin plating additive. In the technical solution disclosed in the patent document, the additive includes the following components by volume: 6-10 parts of tin methanesulfonate, 27-30 parts of methanesulfonic acid, 5-10 parts of electroplating activator, 0.2-0.6 parts of leveling agent, 0.5-2 parts of antioxidant, and 50-65 parts of deionized water, wherein the electroplating activator is composed of polyethylene glycol, methanesulfonic acid, and deionized water; the leveling agent is composed of dye compounds and glycols; and the antioxidant is composed of hydroquinone, methanol, and deionized water.

[0005] A Chinese patent document with publication number CN 102162110A, publication date August 24, 2011, and titled “A Methanesulfonate Tin Plating Electrolyte and a Tin Plating Method for Steel Strip or Steel Plate” discloses a methanesulfonate tin plating electrolyte with a cerium salt as an additive, comprising the following ingredients (g / L): 30 to 120 stannous methanesulfonate, 60 to 180 methanesulfonic acid, 1 to 10 cerium methanesulfonate, 0.1 to 2 antioxidants, 5 to 10 brighteners, and 5 to 15 surfactants.

[0006] The Chinese patent document with publication number CN 112795959 A and publication date May 14, 2021, and titled "A tin-plating solution for reducing the impurity content of the coating and a preparation method thereof" discloses a tin-plating solution for reducing the impurity content of the coating and a preparation method thereof, using deionized water as a solvent, and comprising the following components in concentrations: 0.1-0.5 mol / L of stannous methanesulfonate; 0.3-1 mol / L of methanesulfonic acid; 10-50 g / L of benzoic acid; 1-5 g / L of quaternized polyhydroxy Gemini surfactant; 1-6 g / L of antioxidant; 1-5 g / L of brightener; and 1-10 g / L of complexing agent.

[0007] The Chinese patent document with publication number CN 114517313 A and publication date May 20, 2022, and titled "A tin plating additive for printed circuit boards using methyl sulfonate and a method for preparing the same" discloses a tin plating additive for printed circuit boards using methyl sulfonate and a method for preparing the same, which comprises the following components by weight percentage: 10-20% non-ionic surfactant, 8-15% main brightener, 2-5% auxiliary brightener, 2-5% antioxidant, and 55-78% deionized water.

[0008] However, the above existing antioxidants may be incompatible with the wetting agent, sulfonic acid, brightener and tin plating solution components in the electroplating solution, and may even produce insoluble oil or colloid, which will have an adverse effect on the electroplating process and product quality. 2 There are more and more thin tinplate products with even lower tin plating amounts, and the use of ordinary antioxidants cannot meet the needs of MSA electroplated tin products gradually developing towards lower tin plating amounts. Summary of the invention

[0009] The present invention provides an antioxidant for tin plating with methanesulfonic acid. When the antioxidant is used for tin-plating steel sheets, it can well inhibit the growth of Sn in the plating solution. 2+ Oxidized to Sn 4+ , improve the stability of methanesulfonic acid tin plating solution. The antioxidant can also be well adsorbed on the surface of tinplate, improve the corrosion resistance of tinplate and reduce the porosity of the surface of tinplate.

[0010] The standard reduction potential of tin is about -0.14V vs. SHE, while the potential of tetravalent tin to divalent tin is about +0.15V vs. SHE, so the tin plating solution is very unstable. Antioxidants in acidic tin plating solutions have always attracted much attention. The fundamental reason is to control Sn 2+ The hydrolysis and oxidation transformation of Sn in the plating solution 2+ Concentration. Controlling the pH of the plating solution below 1 can avoid Sn 2+ The hydrolysis of Sn 2+ The oxidation transformation of Sn is a multi-step chemical reaction. 2+ Oxidized by oxygen to form Sn 4+ , and then gradually transformed through the following reactions to finally generate tin mud.

[0011] In order to achieve the above-mentioned purpose, the present invention discloses an antioxidant for methylsulfonic acid tin plating, wherein the weight ratio of the ingredients is: 1 to 10 parts of 8-hydroxyquinoline sulfonate, 1 to 10 parts of citrate, 5 to 10 parts of methylsulfonic acid, 0.1 to 1 part of hydroquinone, and the rest is deionized water. (Total amount is 100 parts)

[0012] Furthermore, the general structural formula of the 8-hydroxyquinoline sulfonate is:

[0013]

[0014] The position of R can be 1, 2, 3, 4, 5, 6, 7, preferably H, carboxyl, halogen, C1-C3 alkyl, substituted C1-C3 alkyl, cyano, nitro, amino, epoxy, etc.; the position of the sulfonate substituent is 2, 3, 4, 5, 6, 7, and Y is H, alkali metal ion, alkaline earth metal ion, transition metal ion and ammonium ion.

[0015] More preferably, the 8-hydroxyquinoline sulfonate is: 8-hydroxyquinoline-5-sulfonate potassium, 5-methyl-8-hydroxyquinoline-3-sulfonate sodium, 6-amino-8-hydroxyquinoline-3-sulfonate calcium, 4-chloro-8-hydroxyquinoline-7-sulfonate potassium, 3-cyano-8-hydroxyquinoline-6-sulfonate potassium, 4-epoxy-8-hydroxyquinoline-2-sulfonate ammonium, 2-ethyl-8-hydroxyquinoline-4-sulfonate barium or 3-bromo-8-hydroxyquinoline-3-sulfonate potassium, etc.

[0016] Furthermore, the citrate is potassium citrate, sodium citrate and ammonium citrate.

[0017] More preferably, the citrate is potassium citrate.

[0018] Furthermore, the catechol is catechol, resorcinol and hydroquinone.

[0019] More preferably, the benzene is hydroquinone.

[0020] According to the above antioxidant for methanesulfonic acid tin plating, preferably, the weight content of the 8-hydroxyquinoline sulfonate is 5 to 10 parts.

[0021] The antioxidant for methanesulfonic acid tin plating of the present invention can effectively inhibit the oxidation of divalent tin ions in a methanesulfonic acid tin plating solution, reduce the oxidation of tin, and thus inhibit the generation of tin oxide and tin mud.

[0022] The antioxidant proposed in the present invention mainly reacts with Sn through complexation. 2+ and Sn 4+ Complexation, inhibition of Sn 2 + Oxidation and Sn 4+ Hydrolysis, preferentially reacting with oxygen in the solution, mainly the sulfonic acid or phenolic hydroxyl compounds in the antioxidant to Sn 4+ Complexation

[0023] The antioxidant of the present invention inhibits Sn 2+ Oxidation and maintenance of Sn 4+ Low concentration, through its own redox to achieve the improvement of the stability of the plating solution, similar to the phenolic stabilizing antioxidants commonly used in methanesulfonic acid tin plating solution, such as hydroquinone, catechol, resorcinol, β-naphthol and ascorbic acid.

[0024] The antioxidant of the present invention can be adsorbed on the surface of the tinplate through polar groups to inhibit the progress of corrosion reaction. After the tinplate is immersed in the antioxidant for a period of time, when the concentration of each component of the antioxidant and the temperature are appropriate, it will be adsorbed on the surface of the tinplate as a corrosion inhibitor, thereby improving the corrosion resistance of the tinplate, thereby providing a certain protection for the tinplate.

[0025] In order to achieve the above-mentioned object of the invention, the present invention also provides a method for preparing a methanesulfonic acid tin plating antioxidant, comprising the steps of:

[0026] (1) weighing an appropriate amount of 8-hydroxyquinoline sulfonate according to a ratio and dissolving it in deionized water to prepare a solution A;

[0027] (2) weighing appropriate amounts of methanesulfonic acid and citrate according to a ratio and adding them to solution A to prepare solution B;

[0028] (3) weighing a suitable amount of hydroquinone and adding it to solution B to prepare solution C;

[0029] (4) Heat solution C to 55° C. to 65° C. and continue stirring until all the above substances are dissolved to obtain an antioxidant.

[0030] According to the above method for preparing an antioxidant for methanesulfonic acid tin plating, preferably, the solution is heated to a temperature of 55° C. to 60° C. and stirred continuously.

[0031] Beneficial technical effects of the present invention

[0032] Through the surface treatment method proposed above, the antioxidant proposed in the present invention mainly reacts with Sn through complexation and inhibition. 2+ and Sn 4+ Complexation, preventing Sn 2+ Oxidation and Sn 4+ Hydrolysis, preferentially reacting with oxygen in the solution, achieving improved plating solution stability through its own redox, and improving the stability of the methanesulfonic acid tin-plating solution. And the prepared antioxidant can be successfully adsorbed on the surface of the tin-plated plate, improving the corrosion resistance of the tin-plated plate. The adsorption behavior of the antioxidant on the surface of the tin-plated plate is closely related to the elements such as O and S in its molecular structure. The polar group with O and S as the central atom contains lone pairs of electrons or unsaturated bonds, has a certain electron-donating ability, and can form coordination bonds with the tin-plated plate for chemical adsorption. Factors such as the spatial stereoscopic structure of the antioxidant, the number of active center groups, the surface roughness of the tin-plated plate, and the charge density of the tin-plated plate surface will have a great impact on the adsorption behavior of the metal surface. At the same time, the 8-hydroxyquinoline sulfonate, citrate, etc., which are preferably used, have good water solubility and will not cause insoluble oil or colloids to be produced, and the strong complexing effect can better meet the production needs of low tin-plated products. Specific embodiments

[0033] For further understanding of the present invention, the present invention is further described in detail below in conjunction with embodiments, but this should not be construed as limiting the scope of the present invention to the following embodiments.

[0034] Example 1

[0035] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 5 parts of 8-hydroxyquinoline-5-sulfonate potassium, 10 parts of potassium citrate, 5 parts of methanesulfonic acid, 0.5 parts of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0036] (1) Weigh 5 parts of potassium 8-hydroxyquinoline-5-sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0037] (2) weighing 5 parts of methanesulfonic acid and 10 parts of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0038] (3) Weighing 0.5 parts of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0039] (4) The solution C is heated to 55° C. and continuously stirred until the potassium 8-hydroxyquinoline-5-sulfonate, potassium citrate, methanesulfonic acid, and hydroquinone are completely dissolved to obtain an antioxidant.

[0040] Example 2

[0041] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of 8-hydroxyquinoline-5-sulfonate potassium, 10 parts of potassium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0042] (1) Weigh 10 parts of potassium 8-hydroxyquinoline-5-sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0043] (2) weighing 10 parts of methanesulfonic acid and 10 parts of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0044] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0045] (4) The solution C is heated to 60° C. and continuously stirred until the potassium 8-hydroxyquinoline-5-sulfonate, potassium citrate, methanesulfonic acid, and hydroquinone are completely dissolved to obtain an antioxidant.

[0046] Example 3

[0047] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is 1 part of potassium 8-hydroxyquinoline-5-sulfonate, 1 part of potassium citrate, 5 parts of methanesulfonic acid, 0.1 part of catechol, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0048] (1) Weigh 1 part of potassium 8-hydroxyquinoline-5-sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0049] (2) weighing 5 parts of methanesulfonic acid and 1 part of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0050] (3) adding 0.1 part of catechol to solution B to prepare solution C;

[0051] (4) Solution C is heated to 55° C. and stirred continuously until potassium 8-hydroxyquinoline-5-sulfonate, potassium citrate, methanesulfonic acid, and catechol are completely dissolved to obtain an antioxidant.

[0052] Example 4

[0053] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of 8-hydroxyquinoline-5-sulfonate potassium, 10 parts of sodium citrate, 10 parts of methanesulfonic acid, 1 part of catechol, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0054] (1) Weigh 10 parts of potassium 8-hydroxyquinoline-5-sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0055] (2) weighing 10 parts of methanesulfonic acid and 10 parts of sodium citrate according to the ratio and adding them to solution A to prepare solution B;

[0056] (3) Weighing 1 part of catechol according to the ratio and adding it to solution B to prepare solution C;

[0057] (4) The solution C is heated to 65° C. and stirred continuously until the potassium 8-hydroxyquinoline-5-sulfonate, sodium citrate, methanesulfonic acid and catechol are completely dissolved to obtain an antioxidant.

[0058] Example 5

[0059] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of 5-methyl-8-hydroxyquinoline-3-sulfonate sodium, 10 parts of potassium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0060] (1) Weigh 10 parts of 5-methyl-8-hydroxyquinoline-3-sulfonate sodium salt according to the ratio and dissolve it in deionized water to prepare solution A;

[0061] (2) weighing 10 parts of methanesulfonic acid and 10 parts of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0062] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0063] (4) Solution C is heated to 65° C. and continuously stirred until all the 5-methyl-8-hydroxyquinoline-3-sulfonate sodium, potassium citrate, methanesulfonic acid, and hydroquinone are dissolved to obtain an antioxidant.

[0064] Example 6

[0065] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of 6-amino-8-hydroxyquinoline-3-sulfonate calcium, 10 parts of potassium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0066] (1) Weigh 10 parts of 6-amino-8-hydroxyquinoline-3-sulfonate calcium salt according to the ratio and dissolve it in deionized water to prepare solution A;

[0067] (2) weighing 10 parts of methanesulfonic acid and 10 parts of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0068] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0069] (4) The solution C is heated to 65° C. and stirred continuously until the 6-amino-8-hydroxyquinoline-3-sulfonate calcium, potassium citrate, methanesulfonic acid and hydroquinone are completely dissolved to obtain an antioxidant.

[0070] Example 7

[0071] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of potassium 4-chloro-8-hydroxyquinoline-7-sulfonate, 10 parts of potassium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0072] (1) Weigh 10 parts of potassium 4-chloro-8-hydroxyquinoline-7-sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0073] (2) weighing 10 parts of methanesulfonic acid and 10 parts of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0074] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0075] (4) Solution C is heated to 65° C. and continuously stirred until potassium 4-chloro-8-hydroxyquinoline-7-sulfonate, potassium citrate, methanesulfonic acid, and hydroquinone are completely dissolved to obtain an antioxidant.

[0076] Example 8

[0077] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of potassium 3-cyano-8-hydroxyquinoline-6-sulfonate, 10 parts of potassium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0078] (1) Weigh 10 parts of potassium 3-cyano-8-hydroxyquinoline-6-sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0079] (2) weighing 10 parts of methanesulfonic acid and 10 parts of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0080] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0081] (4) The solution C is heated to 65° C. and continuously stirred until the potassium 3-cyano-8-hydroxyquinoline-6-sulfonate, potassium citrate, methanesulfonic acid and hydroquinone are completely dissolved to obtain an antioxidant.

[0082] Example 9

[0083] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of 4-epoxy-8-hydroxyquinoline-2-sulfonic acid ammonium, 10 parts of potassium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0084] (1) Weigh 10 parts of 4-epoxy-8-hydroxyquinoline-2-ammonium sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0085] (2) weighing 10 parts of methanesulfonic acid and 10 parts of potassium citrate according to the ratio and adding them to solution A to prepare solution B;

[0086] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0087] (4) The solution C is heated to 65° C. and stirred continuously until the 4-epoxy-8-hydroxyquinoline-2-sulfonate ammonium, potassium citrate, methanesulfonic acid and hydroquinone are completely dissolved to obtain an antioxidant.

[0088] Example 10

[0089] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of 2-ethyl-8-hydroxyquinoline-4-sulfonate barium, 10 parts of sodium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0090] (1) Weigh 10 parts of 2-ethyl-8-hydroxyquinoline-4-sulfonate barium according to the ratio and dissolve it in deionized water to prepare solution A;

[0091] (2) weighing 10 parts of methanesulfonic acid and 10 parts of sodium citrate according to the ratio and adding them to solution A to prepare solution B;

[0092] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0093] (4) The solution C is heated to 65° C. and stirred continuously until the 2-ethyl-8-hydroxyquinoline-4-sulfonate barium, sodium citrate, methanesulfonic acid and hydroquinone are completely dissolved to obtain an antioxidant.

[0094] Embodiment 11

[0095] An antioxidant for methanesulfonic acid tin plating, the weight composition ratio of which is: 10 parts of 3-bromo-8-hydroxyquinoline-3-sulfonate potassium, 10 parts of sodium citrate, 10 parts of methanesulfonic acid, 1 part of hydroquinone, and the rest is deionized water. The preparation method of the above antioxidant is as follows:

[0096] (1) Weigh 10 parts of potassium 3-bromo-8-hydroxyquinoline-3-sulfonate according to the ratio and dissolve it in deionized water to prepare solution A;

[0097] (2) weighing 10 parts of methanesulfonic acid and 10 parts of sodium citrate according to the ratio and adding them to solution A to prepare solution B;

[0098] (3) Weighing 1 part of hydroquinone according to the ratio and adding it to solution B to prepare solution C;

[0099] (4) Solution C is heated to 65° C. and continuously stirred until potassium 3-bromo-8-hydroxyquinoline-3-sulfonate, sodium citrate, methanesulfonic acid, and hydroquinone are completely dissolved to obtain an antioxidant.

[0100] Comparative Example 1

[0101] An antioxidant for methanesulfonic acid tin plating is disclosed, and the weight composition ratio of the antioxidant is: 10 parts of hydroquinone, 10 parts of methanol, and the rest of deionized water, which are mixed and prepared.

[0102] Comparative Example 2

[0103] An antioxidant for methanesulfonic acid tin plating is disclosed, and the weight composition ratio of the antioxidant is: 10 parts of hydroquinone, 10 parts of methanol, and the rest of deionized water, which are mixed and prepared.

[0104] Bath performance test

[0105] Under the experimental conditions of simulating the oxidation of the plating solution by continuously pumping oxygen from the air into the plating solution during high-speed electroplating, the performance of the antioxidant was evaluated by detecting the change in the concentration of tin ions in the electroplating solution. The original electroplating solution was: 60g / L of divalent tin ions, 100g / L of methanesulfonic acid, and oxygen was continuously pumped into the solution at a rate of 500mL / min for 120h. The solution temperature was maintained at 50℃ (±5℃), and then the antioxidant was added. By adding different types of tin plating antioxidants of Examples 1-10 and Comparative Examples 1-2, the addition amount was controlled to be 1.0g / L, and the concentration change value of divalent tin ions before and after was detected (in percentage).

[0106]

[0107]

[0108] Steel plate porosity determination

[0109] The porosity test and analysis was carried out using the metal coating porosity test-iron reagent test in GB / T17721-1999 to determine the number of pores per unit area of ​​the electroplated tinplate obtained by adding the above antioxidant.

[0110]

[0111]

[0112] It is shown that the addition of the antioxidant of the present invention can effectively inhibit the Sn in the plating solution. 2+ Oxidized to Sn 4+ , improve the stability of methanesulfonic acid tin plating solution. And the antioxidant can also be well adsorbed on the surface of the tinplate, improve the corrosion resistance of the tinplate, and reduce the porosity of the tinplate surface.

[0113] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. An antioxidant for methanesulfonic acid tin plating, characterized in that, The weight ratio of the ingredients is: 1 to 10 parts of 8-hydroxyquinoline sulfonate, 1 to 10 parts of citrate, 5 to 10 parts of methanesulfonic acid, 0.1 to 1 part of hydroquinone, and the rest is deionized water.

2. The antioxidant for methanesulfonic acid tin plating according to claim 1, characterized in that The general structural formula of the 8-hydroxyquinoline sulfonate is: The position of R can be 1, 2, 3, 4, 5, 6 or 7, and is H, carboxyl, halogen, C1-C3 alkyl, substituted C1-C3 alkyl, cyano, nitro, amino, epoxy, etc.; the position of the sulfonate substituent is 2, 3, 4, 5, 6, 7, and Y is H, alkali metal ion, alkaline earth metal ion, transition metal ion and ammonium ion.

3. The antioxidant for methanesulfonic acid tin plating according to claim 2, characterized in that, The 8-hydroxyquinoline sulfonate is: 8-hydroxyquinoline-5-sulfonate potassium, 5-methyl-8-hydroxyquinoline-3-sulfonate sodium, 6-amino-8-hydroxyquinoline-3-sulfonate calcium, 4-chloro-8-hydroxyquinoline-7-sulfonate potassium, 3-cyano-8-hydroxyquinoline-6-sulfonate potassium, 4-epoxy-8-hydroxyquinoline-2-sulfonate ammonium, 2-ethyl-8-hydroxyquinoline-4-sulfonate barium or 3-bromo-8-hydroxyquinoline-3-sulfonate potassium.

4. The antioxidant for methanesulfonic acid tin plating according to claim 1, characterized in that The citrate is potassium citrate, sodium citrate or ammonium citrate.

5. The antioxidant for methanesulfonic acid tin plating according to claim 4, characterized in that, The citrate is potassium citrate.

6. The antioxidant for methanesulfonic acid tin plating according to claim 1, characterized in that The catechol is catechol, resorcinol or hydroquinone.

7. The antioxidant for methanesulfonic acid tin plating according to claim 6, characterized in that The hydroquinone is hydroquinone.

8. The antioxidant for methanesulfonic acid tin plating according to claim 1, characterized in that: The content of the 8-hydroxyquinoline sulfonate is 5 to 10 parts.

9. A method for preparing an antioxidant for methanesulfonic acid tin plating according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) weighing an appropriate amount of 8-hydroxyquinoline sulfonate according to a ratio and dissolving it in deionized water to prepare a solution A; (2) weighing appropriate amounts of methanesulfonic acid and citrate according to a ratio and adding them to solution A to prepare solution B; (3) weighing a suitable amount of hydroquinone and adding it to solution B to prepare solution C; (4) Heat solution C to 55° C. to 65° C. and continue stirring until all the above substances are dissolved to obtain an antioxidant.

10. The method for preparing an antioxidant for methanesulfonic acid tin plating according to claim 9, characterized in that: The solution was heated to 55°C to 60°C and stirred continuously.

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