Tinning additive

Abstract

The invention discloses a tin plating additive which comprises 26-433 mL / L of tin methanesulfonate, 20-200 mL / L of methanesulfonic acid, 1-40 g / L of a stabilizer, 1-40 mg / L of a main brightener, 0.1-10 mL / L of an auxiliary brightener, 0.1-5 g / L of a dispersing agent, 0.1-10 mL / L of an agent and the balance of deionized water. The tinning additive is good in dispersing capacity and covering capacity in the electroplating process; and the plating layer is relatively strong in binding force, smooth and bright in surface, and free from the defects of hard spots, local plating layer and the like.

Description

Technical Field

[0001] The invention relates to the field of circuit board electroplating, in particular to a tin plating additive for improving the brightness of tin plating. Background Art

[0002] Tin plating by electrochemical deposition is a common surface treatment technology. Since tin has excellent antioxidant properties, it can form a dense tin oxide film on the metal surface to prevent the metal surface from contacting with the air, which can greatly improve the metal's antioxidant capacity.

[0003] The electroplating tinning process is currently divided into two major systems: alkaline tinning and acidic tinning. Among them, the alkaline tinning temperature is generally high, the alkaline system plating solution is unstable, and it is greatly affected by the alkalinity pH value, resulting in the differentiation and deterioration of harmful Sn2+ complexes, which affects the increase of the electroplating potential fluctuation. The added sodium hydroxide is also easy to hydrolyze sodium stannate to form tin mud precipitation. At the same time, the alkaline tinning process has smaller conductive ions and lower current efficiency, which increases the process cost. Due to the above-mentioned shortcomings of the alkaline tinning process, it is gradually replaced by acidic tinning. Acidic tinning has good conductivity, high current efficiency, no need for heating, stable plating solution composition, reduced influence of pH value, small change in electroplating potential, and dense and uniform coating structure. The acidic tinning systems that are widely used in the market currently include sulfate system, fluoroborate system, halide system and alkyl sulfonate system. Among them, the methanesulfonic acid plating solution is favored because it is green and environmentally friendly, and its stability is much higher than that of the sulfate system. In addition, the methanesulfonic acid system is suitable for obtaining a uniform coating over a wide current density range. At the same time, the plating solution has stable composition, fast deposition speed, and is suitable for operation at high temperatures, making it stand out among many acidic plating solutions. In addition, the cost of raw materials for methanesulfonic acid has dropped significantly in recent years, and the tin plating process of the methanesulfonic acid system has developed rapidly.

[0004] Patent CN101922026A discloses a methanesulfonic acid system matte pure tin plating solution formula and its electroplating process, but its additives contain heterocyclic compounds and amine compounds, both of which are environmentally unfriendly. Moreover, the plating solution described in the patent contains a relatively high concentration of heterocyclic organic solvents, which are easily decomposed and volatilized in a high-speed electroplating process and in strong convection. In addition, the amount of tin sludge precipitated in the plating solution is relatively large, making the plating solution extremely unstable, resulting in excessive consumption and a significant increase in production costs.

[0005] Patent CN105755512 introduces a combination antioxidant of phytic acid, citric acid, ascorbic acid, and ethylenediaminetetraacetic acid. This combination antioxidant is more effective than diphenol antioxidants and can keep the plating solution from becoming turbid and deteriorating for a longer time. However, it does not clearly explain the effect of the coating produced by this combination antioxidant in methanesulfonic acid system electroplating.

[0006] Patent CN111472026 discloses a bright tin plating solution formula. The components and process are convenient, but its additives contain formaldehyde and some aldehyde polymers. These compounds are very harmful to the human body, and some of the additives contained in it are not friendly to the environment. Summary of the invention

[0007] The purpose of the present invention is to provide a tinning additive that produces a uniform and dense coating structure; the specific technical solution is:

[0008] A tin plating additive, comprising the following mass concentration components:

[0009] Tin methanesulfonate 26-433mL / L,

[0010] Methanesulfonic acid 20-200mL / L,

[0011] Stabilizer 1-40g / L,

[0012] Main brightener 1-40mg / L,

[0013] The first auxiliary brightener 0.1-10mL / L,

[0014] The second auxiliary brightener 0.1-10mL / L,

[0015] Dispersant 0.1-5g / L,

[0016] Surfactant 0.1-10mL / L,

[0017] The rest was deionized water.

[0018] Furthermore, the bulk density ratio of the tin methanesulfonate to the methanesulfonic acid is 130 mL / L:100 mL / L.

[0019] Furthermore, the main brightener is a mixture of one or more of rosin, dibenzylideneacetone, p-hydroxybenzylideneacetone, acetone, and pine distillate oil.

[0020] Furthermore, the first auxiliary brightener is a mixture of one or more of citrus aldehyde, citrus aldehyde and cinnamaldehyde.

[0021] Furthermore, the second auxiliary brightener is a mixture of one or more of 3,3'-dithiobis(1-propanesulfonic acid) disodium (SPS), sodium 3-mercapto-1-propane sulfonate (MPS), isothiourea propanesulfonic acid inner salt (UPS), sodium N,N-dimethyldithiocarboxamide propane sulfonate (DPS), sodium alcoholthiopropane sulfonate (HP), thiourea and their derivatives.

[0022] Furthermore, the stabilizer is a mixture of one or more of 2,3,5-trimethylphenol, 2,6-dibromophenol and 2,3,6-trimethylphenol.

[0023] Furthermore, the dispersant is a mixture of one or more of polyethylene glycol 6000, polypropylene glycol, polypropylene alcohol, castor oil polyethylene ether, polyoxyethylene lauryl ether, and coconut amine polyoxyethylene ether.

[0024] Furthermore, the surfactant is one or a mixture of nonylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

[0025] The tin plating additive of the present invention has good dispersibility and covering ability in the electroplating process; the coating has strong bonding force, the surface is smooth and bright, and there are no defects such as pitting and local coating absence; no harmful gas is generated in the entire electroplating process, thus avoiding environmental pollution, and at the same time, it also solves the problems of low brightness of tin plating in the prior art, such as insufficient technical ability, and shows strong applicability and practicality. . BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the effect diagram of the Hull groove test piece of Example 1;

[0027] Figure 2 This is the effect diagram of the Hull groove test piece of Example 2;

[0028] Figure 3 This is the effect diagram of the Hull groove test piece of Example 3;

[0029] Figure 4 This is the effect diagram of the Hull groove test piece of Example 4;

[0030] Figure 5 This is the effect diagram of the Hull groove test piece of Example 5;

[0031] Figure 6 This is the effect diagram of the Hull slot test piece of comparative example 1;

[0032] Figure 7 This is the effect diagram of the Hull slot test piece of comparative example 2;

[0033] Figure 8 This is the effect diagram of the Hull groove test piece of comparative example 3;

[0034] Fig. 9 This is the effect diagram of the Hull groove test piece of comparative example 4;

[0035] Fig.10 This is a SEM photo of a pure copper specimen magnified 20k times;

[0036] Fig.11 This is a 20k times magnified SEM photograph of the tin-plated plate obtained in Example 1 at 3A / dm2 and room temperature;

[0037] Fig.12 This is a 20k-fold SEM photograph of the tinplate obtained in Example 2 at 3A / dm2 and room temperature. DETAILED DESCRIPTION

[0038] The present invention is described more fully below using embodiments. The present invention can be embodied in many different forms and should not be construed as being limited to the exemplary embodiments described herein.

[0039] The purity specifications of the additives used in the present invention are specifically described here:

[0040]

[0041]

[0042] Example 1

[0043] The components and contents of the methanesulfonate bright tin plating solution of this embodiment are: 50 mL / L of methanesulfonic acid, 65 mL (7.5 g / L) of tin methanesulfonate, 1 mg / L of pine oil, 1 mg / L of rosin, 1 mL / L of citrus aldehyde, 0.1 mL / L of isothioureapropanesulfonic acid inner salt (UPS), 1 g / L of lauryl ether, 1 g / L of modified polyether, 10 g / L of 2,6-dibromophenol, 1 mL / L of anhydrous ethanol, and the rest is deionized water.

[0044] Prepare 1L of the methanesulfonate bright tin plating solution described in this embodiment, the specific steps are as follows:

[0045] (1) Take a 1L beaker, add 600mL of pure water, take 50mL of methanesulfonic acid and slowly add it into the water, let it stand until the solution cools to room temperature; then add 65mL of tin methanesulfonate solution;

[0046] (2) Take a clean beaker, add 50 mL of deionized water, add 1 mg of pine distillate, 1 mg of rosin and 1 g of lauryl ether, heat and dissolve at 50°C in a water bath and stir until they are completely dissolved, and cool to room temperature;

[0047] (3) Take a clean beaker, add 50 mL of deionized water and 1 mL of citrus aldehyde, and stir until completely dissolved;

[0048] (4) Take a clean beaker, add 50 mL of deionized water, 0.1 mL of isothioureapropanesulfonic acid inner salt (UPS), and 1 mL of anhydrous ethanol, heat and stir in a 50°C water bath to completely dissolve, and cool to room temperature;

[0049] (5) Take a clean beaker, add 50 mL of deionized water and 10 g of 2,6-dibromophenol, and stir until it is completely dissolved;

[0050] (6) Add the solutions obtained in steps (2), (3), (4) and (5) and 1 mL of anhydrous ethanol to the solution obtained in step (1), stir thoroughly to mix evenly, and add water to make the volume to 1 L, thereby obtaining a methanesulfonate bright tin plating solution.

[0051] In this example, the electroplating was carried out in a 267 mL Hull tank, the anode was a 99.9% tin plate, the cathode was a pure copper sheet, and the current density was 2 A / dm 2 , the temperature is room temperature.

[0052] like Figure 1 As shown, the electroplating solution prepared in this embodiment has good dispersibility and covering ability during the electroplating process; the coating has strong bonding strength, a smooth and bright surface, and no defects such as pitting and local lack of coating.

[0053] Example 2

[0054] The components and contents of the methanesulfonate bright tin plating solution of this embodiment are: methanesulfonic acid 100 mL / L, tin methanesulfonate 15 g / L, pine distillate oil 1 mg / L, rosin 2 mg / L, orange aldehyde 3 mL / L, isothiourea propanesulfonic acid inner salt (UPS) 0.2 mL / L, lauryl ether 1 g / L, modified polyether 2 g / L, 2,6-dibromophenol 15 g / L, anhydrous ethanol 1 mL / L, and the rest is deionized water.

[0055] Prepare 1L of the methanesulfonate bright tin plating solution described in this embodiment, the specific steps are as follows:

[0056] (1) Take a 1L beaker, add 400mL of pure water, take 100mL of methanesulfonic acid and slowly add it into the water, let it stand until the solution cools to room temperature; then add 130mL of tin methanesulfonate solution;

[0057] (2) Take a clean beaker, add 50 mL of deionized water, add 1 mg of pine distillate, 2 mg of rosin, 1 g of lauryl ether, and 2 g of modified polyether, heat to 50°C in a water bath to dissolve and stir until it is completely dissolved, and let it stand until the solution cools to room temperature;

[0058] (3) Take a clean beaker, add 50 mL of deionized water and 3 mL of citrus aldehyde, and stir until completely dissolved;

[0059] (4) Take a clean beaker, add 50 mL of deionized water, 0.2 mL of isothioureapropanesulfonic acid inner salt (UPS), and 1 mL of anhydrous ethanol, heat and stir in a 50°C water bath to completely dissolve, and cool to room temperature;

[0060] (5) Take a clean beaker, add 50 mL of deionized water, then add 15 g of 2,6-dibromophenol, and stir until it is completely dissolved;

[0061] (6) Add the solutions obtained in steps (2), (3), (4) and (5) and 1 mL of anhydrous ethanol to the solution obtained in step (1), stir thoroughly to mix evenly, and add water to make the volume to 1 L, thereby obtaining a methanesulfonate bright tin plating solution.

[0062] In this example, the electroplating was carried out in a 267 mL Hull tank, the anode was a 99.9% tin plate, the cathode was a pure copper sheet, and the current density was 2 A / dm 2 , the temperature is room temperature.

[0063] like Figure 2 As shown, the electroplating solution prepared in this embodiment has good dispersibility and covering ability during the electroplating process; the coating has strong bonding strength, a smooth and bright surface, and no defects such as pitting and local lack of coating.

[0064] Example 3

[0065] The components and contents of the methanesulfonate bright tin plating solution of this embodiment are: 200 mL / L of methanesulfonic acid, 30 g / L of tin methanesulfonate, 2 mg / L of rosin, 5 mL / L of citrus aldehyde, 0.5 mL / L of isothioureapropanesulfonic acid inner salt (UPS), 2 g / L of lauryl ether, 2 g / L of modified polyether, 30 g / L of 2,6-dibromophenol, 1 mL / L of anhydrous ethanol, and the rest is deionized water.

[0066] Prepare 1L of the methanesulfonate bright tin plating solution described in this embodiment, the specific steps are as follows:

[0067] (1) Take a 1L beaker, add 400mL of pure water, take 200mL of methanesulfonic acid and slowly add it into the water, let it stand until the solution cools to room temperature; then add 260mL of tin methanesulfonate solution;

[0068] (2) Take a clean beaker, add 50 mL of deionized water, add 2 mg of rosin, 2 g of lauryl ether, and 2 g of modified polyether, heat to 50 ° C in a water bath to dissolve and stir until it is completely dissolved, and let it stand until the solution cools to room temperature;

[0069] (3) Take a clean beaker, add 50 mL of deionized water and 5 mL of citrus aldehyde, and stir until completely dissolved.

[0070] (4) Take a clean beaker, add 50 mL of deionized water, 0.5 mL of isothioureapropanesulfonic acid inner salt (UPS), and 1 mL of anhydrous ethanol, heat and stir in a 50°C water bath to completely dissolve, and cool to room temperature;

[0071] (5) Take a clean beaker, add 50 mL of deionized water, then add 30 g of 2,6-dibromophenol, and stir until it is completely dissolved;

[0072] (6) Add the solutions obtained in steps (2), (3), (4) and (5) and 1 mL of anhydrous ethanol to the solution obtained in step (1), stir thoroughly to mix evenly, and add water to make the volume to 1 L, thereby obtaining a methanesulfonate bright tin plating solution.

[0073] The anode used in this embodiment is 99.9% tin plate, the cathode is pure copper sheet, and the current density is 3A / dm 2 , the temperature is room temperature.

[0074] Example 4

[0075] The components and contents of the methanesulfonate bright tin plating solution of this embodiment are: methanesulfonic acid 25 mL / L, tin methanesulfonate 3.75 g / L, pine distillate 2 mg / L, rosin 1 mg / L, citrus aldehyde 1 mL / L, isothiourea propanesulfonic acid inner salt (UPS) 0.5 mg / L, polyoxyethylene lauryl ether 2 g / L, fatty alcohol polyoxyethylene ether 1 mL / L, 2,6-dibromophenol 15 g / L, anhydrous ethanol 2 mL / L, and the rest is deionized water.

[0076] Prepare 1L of the methanesulfonate bright tin plating solution described in this embodiment, the specific steps are as follows:

[0077] (1) Take a 1L beaker, add 600mL of pure water, take 25mL of methanesulfonic acid and slowly add it into the water, let it stand until the solution cools to room temperature; then add 22mL of tin methanesulfonate solution;

[0078] (2) Take a clean beaker, add 50 mL of deionized water, add 2 mg of pine distillate oil and 2 g of polyoxyethylene lauryl ether, heat and dissolve at 50° C. in a water bath and stir until they are completely dissolved, and cool to room temperature;

[0079] (3) Take a clean beaker, add 50 mL of deionized water and 1 mL of citrus aldehyde, and stir until completely dissolved.

[0080] (4) Take a clean beaker, add 50 mL of deionized water, 0.5 mg of isothioureapropanesulfonic acid inner salt (UPS), and 2 mL of anhydrous ethanol, heat and stir in a 50°C water bath to completely dissolve, and cool to room temperature.

[0081] (5) Take a clean beaker, add 50 mL of deionized water and 15 g of 2,6-dibromophenol, and stir until it is completely dissolved.

[0082] (6) Add the solutions obtained in steps (2), (3), (4) and (5) and 2 mL of anhydrous ethanol to the solution obtained in step (1), stir thoroughly to mix evenly, and add water to make the volume to 1 L, thereby obtaining a methanesulfonate bright tin plating solution.

[0083] In this embodiment, the electroplating was carried out in a 267 mL Hull tank, the anode was a 99.9% tin plate, the cathode was a pure copper sheet, the current density was 2 A / dm2, and the temperature was room temperature.

[0084] The electroplating solution prepared in this embodiment has good dispersibility and covering ability during the electroplating process; the coating has strong bonding strength, a smooth and bright surface, and no defects such as pitting and local lack of coating.

[0085] Example 5

[0086] The components and contents of the methanesulfonate bright tin plating solution of this embodiment are: methanesulfonic acid 50 mL / L, tin methanesulfonate 3.75 g / L, pine distillate oil 1 mg / L, rosin 2 mg / L orange aldehyde 1 mL / L, isothiourea propanesulfonic acid inner salt (UPS) 0.2 mg / L, polyoxyethylene lauryl ether 2 g / L, fatty alcohol polyoxyethylene ether 2 mL / L, 2,6-dibromophenol 15 g / L, anhydrous ethanol 1 mL / L, and the rest is deionized water.

[0087] Prepare 1L of the methanesulfonate bright tin plating solution described in this embodiment, the specific steps are as follows:

[0088] (1) Take a 1L beaker, add 600mL of pure water, take 50mL of methanesulfonic acid and slowly add it into the water, let it stand until the solution cools to room temperature; then add 22mL of tin methanesulfonate solution;

[0089] (2) Take a clean beaker, add 50 mL of deionized water, add 1 mg of pine oil, 2 mg of rosin, 2 mL of fatty alcohol polyoxyethylene ether and 2 g of polyoxyethylene lauryl ether, heat and dissolve at 50° C. in a water bath and stir until they are completely dissolved, and cool to room temperature;

[0090] (3) Take a clean beaker, add 50 mL of deionized water and 1 mL of citrus aldehyde, and stir until completely dissolved.

[0091] (4) Take a clean beaker, add 50 mL of deionized water, 0.2 mg of isothioureapropanesulfonic acid inner salt (UPS), and 1 mL of anhydrous ethanol, heat and stir in a 50°C water bath to completely dissolve, and cool to room temperature.

[0092] (5) Take a clean beaker, add 50 mL of deionized water and 15 g of 2,6-dibromophenol, and stir until it is completely dissolved.

[0093] (6) Add the solutions obtained in steps (2), (3), (4) and (5) and 1 mL of anhydrous ethanol to the solution obtained in step (1), stir thoroughly to mix evenly, and add water to make the volume to 1 L, thereby obtaining a methanesulfonate bright tin plating solution.

[0094] In this embodiment, the electroplating was carried out in a 267 mL Hull tank, the anode was a 99.9% tin plate, the cathode was a pure copper sheet, the current density was 2 A / dm2, and the temperature was room temperature.

[0095] The electroplating solution prepared in this embodiment has good dispersibility and covering ability during the electroplating process; the coating has strong bonding strength, a smooth and bright surface, and no defects such as pitting and local lack of coating.

[0096] Plating solution performance test:

[0097] 1) Hull slot test piece test: 267mL plating solution was used for the test. The test piece was made of pure copper plate, 100mm long, 65mm high and 3mm thick. The experiment was carried out at room temperature. The limiting current density of the plating solution prepared in Example 1 can reach 15A / dm 2 ,like Figure 1 As shown, there is no unqualified coating in the entire current density range, which can meet the current tinning process.

[0098] 2) Dispersion ability test. The test was conducted by the near-far cathode method. The plating tank was a 1500mL Haring tank. The cathode was a pure copper plate with a thickness of 0.3mm and a size of 6.5mm×100mm. A 99.9% tin anode with the same size as the cathode was used. The test current density was 3.0A / dm 2 , place an anode between two cathode test pieces, with the distance ratio between the far cathode and the near cathode being 2:1. After electroplating at room temperature, take out the cathode and clean it. Weigh the increment of deposited metal on the far and near cathodes, and calculate the dispersion capacity of the plating solution by the following formula.

[0099]

[0100] Where: T——dispersion capacity;

[0101] K——Ratio of the distance between the far cathode and the near cathode and the anode;

[0102] m 1 ——The mass of metal deposited near the cathode, in g;

[0103] m 2 ——The mass of metal deposited on the far cathode, in g.

[0104] The additives provided in the above embodiments and other additives sold on the market were tested for throwing power three times and their average values ​​were taken (wherein Comparative Example 1 is the effect shown by the basic plating solution). The data are as follows:

[0105] Example Throwing capacity Example 1 92.8％ Example 2 83.7％ Example 3 77.6％ Example 4 68.5％ Example 5 60.7％ Comparative Example Throwing capacity Comparative Example 1 43.7％ Comparative Example 2 57.3％ Comparative Example 3 78.5％ Comparative Example 4 76.7％

[0106] 3) Test of coating brightness. Use 3nh gloss tester to test coating brightness, the results are as follows:

[0107]

[0108]

[0109] Note: In the Hull slot test piece effect diagram, the larger the bright area range, the more the formula can achieve a bright coating effect in a larger current range.

[0110] Coating performance test

[0111] 1) A 100mm*65mm*3mm pure copper specimen was used as the research object. Fig.10 It can be seen that there are a large number of rolling lines and rolling pits on the surface of the pure copper test piece, which places extremely high demands on the plating solution performance and additives.

[0112] 2) Surface roughness test of coating. The roughness of the coatings of Examples 1-3 and Comparative Examples 1-4 was measured using a laser confocal microscope, and the results are as follows:

[0113] Example Ra R S Unplated sample 0.187 1.289 2.218 Example 1 0.015 0.085 0.49 Example 2 0.041 0.244 0.64 Example 3 0.066 0.378 0.822 Example 4 0.071 0.486 1.092 Example 5 0.086 0.686 2.001 Comparative Example 1 1.439 9.811 21.886 Comparative Example 2 0.080 0.613 1.905 Comparative Example 3 0.0517 0.354 0.587 Comparative Example 4 0.037 0.220 0.533

[0114] The results show that the surface roughness effect of the plated surface in Example 1 is much better than that of the other examples.

[0115] 3) Test of plating solution stability performance.

[0116] Each example was electroplated every other month to observe the electroplating effect and evaluate the stability of the plating solution. The results are as follows:

[0117]

[0118] Note: √ means the effect is the same as the initial configuration of the plating solution, ○ means the effect is worse, and × means the plating solution has completely failed.

[0119] The electroplating solution prepared in this embodiment has good dispersibility and covering ability during the electroplating process; the coating has strong bonding strength, a smooth and bright surface, and no defects such as pitting and local lack of coating.

[0120] The above is a specific implementation method of the present invention, which is mainly applicable to the field of electronic copper foil. The formula of the present invention is reasonable and can greatly reduce the production cost. No harmful gas will be generated during the entire electroplating process, thus avoiding environmental pollution. At the same time, it also solves the problems of low brightness of tin plating in the prior art and insufficient technical capabilities, showing strong applicability and practicality.

[0121] The above examples are only used to illustrate the present invention. In addition, there are many different implementations. These implementations are all conceivable by those skilled in the art after understanding the concept of the present invention, so they are not listed here one by one.

Claims

1. A tinning additive, characterized in that: Includes the following mass concentration components: Tin methanesulfonate 26-433 mL / L, Methanesulfonic acid 20-200mL / L, Stabilizer 1-40g / L, Main brightener 1-40mg / L, The first auxiliary brightener 0.1-10mL / L, The second auxiliary brightener 0.1-10mL / L, Dispersant 0.1-5g / L, Surfactant 0.1-10mL / L, The rest was deionized water.

2. The tin plating additive according to claim 1, characterized in that: The bulk density ratio of the tin methanesulfonate to the methanesulfonic acid is 130 mL / L: 100 mL / L.

3. The tin plating additive according to claim 1, characterized in that: The main brightener is a mixture of one or more of rosin, dibenzylideneacetone, p-hydroxybenzylideneacetone, acetone and pine distillate oil.

4. The tin plating additive according to claim 1, characterized in that: The first auxiliary brightener is a mixture of one or more of citrus aldehyde, citrus aldehyde and cinnamaldehyde.

5. The tin plating additive according to claim 1, characterized in that: The second auxiliary brightener is a mixture of one or more of 3,3'-dithiobis(1-propanesulfonic acid) disodium (SPS), 3-mercapto-1-propanesulfonate sodium (MPS), isothiourea propanesulfonic acid inner salt (UPS), sodium N,N-dimethyldithiocarboxamide propane sulfonate (DPS), sodium alcoholthiopropane sulfonate (HP), thiourea and their derivatives.

6. The tin plating additive according to claim 1, characterized in that: The stabilizer is a mixture of one or more of 2,3,5-trimethylphenol, 2,6-dibromophenol and 2,3,6-trimethylphenol.

7. The tin plating brightener formulation of the methanesulfonic acid system according to claim 1, characterized in that The dispersant is a mixture of one or more of polyethylene glycol 6000, polypropylene glycol, polypropylene alcohol, castor oil polyethylene ether, polyoxyethylene lauryl ether and coconut amine polyoxyethylene ether.

8. The tin plating additive according to claim 1, characterized in that: The surfactant is one or a mixture of nonylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

Images