High-compactness punching tin-plated copper strip electroplating solution and processing method

Abstract

The invention relates to the technical field of metal tin plating, and discloses a high-compactness punched tin-plated copper strip electroplating solution and a processing method.The electroplating solution comprises methanesulfonic acid, tin methanesulfonate, a 180 additive and a 180 adjuvant, and the processing method comprises the steps of punching, cathode and anode cross electrolytic degreasing, surface activation, tin plating and washing and drying. The auxiliary agent 180 is adopted to replace an antioxidant, a chromium-containing passivator or cyanide in a traditional electroplating solution, so that the electroplating solution is more environment-friendly and safer, and the electroplating solution is always in a dynamic equilibrium process in the operation process of a tin plating system by matching with high-content methanesulfonic acid and tin methanesulfonate. The anode tin is rapidly transferred to the cathode punched copper strip, a uniform tin coating of 1.5-3.0 microns is formed on the surface of the punched copper strip, the coating and a matrix are well combined, and the coating is fine in crystal, free of pinholes and pits, free of oxidation and free of blackening.

Description

Technical Field

[0001] The invention relates to the technical field of metal tinning, and in particular to a high-density punching tinned copper strip electroplating solution and a processing method. Background Art

[0002] Punched tinned copper strip is an ideal carrier for the negative active material of nickel-zinc batteries. Nickel-zinc batteries have the following significant advantages: (1) high operating voltage, reaching 1.65 volts; (2) excellent specific energy; (3) excellent discharge power; (4) significant environmental protection characteristics, ensuring intrinsic safety and pollution-free; (5) relatively low cost, providing excellent cost-effectiveness, etc., which makes nickel-zinc batteries widely used in green transportation, power tools and electrochemical energy storage fields.

[0003] During the production process of punched tin-plated copper strip, a layer of metallic tin is electroplated on the surface of the copper strip, which not only effectively prevents the oxidation corrosion of copper, but also significantly improves the winding and welding performance of the electrode, thereby better adapting to the high current discharge requirements of nickel-zinc batteries.

[0004] However, in the process of electroplating tin on the surface of copper strip, some challenges may be encountered, such as impurity ion replacement, cathode hydrogen evolution and other side reactions. The occurrence of these side reactions will cause defects such as blackening, pinholes, pitting and pores on the surface of the coating, resulting in reduced density and corrosion resistance of the coating, seriously affecting the quality and performance of the product. Therefore, antioxidants, chromium-containing passivation or cyanide and other substances are added to the commonly used tin plating solution formula. This leads to the consumption of the above ingredients in the plating solution with the product after a period of production, resulting in a decrease in the proportion of effective ingredients in the plating solution, which in turn leads to a series of problems such as the manifestation of surface defects, low thickness and reduced density of the coating, and ultimately leads to a decrease in the overall quality of the product. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a high-density punched tin-plated copper strip electroplating solution and processing method, which has no defects such as blackening, pinholes, pitting, pores, etc. on the coating surface and has strong coating bonding and good corrosion resistance.

[0006] In order to solve the above technical problems, the embodiment of the present invention provides a high-density punching tinned copper strip electroplating solution, comprising:

[0007] Methanesulfonic acid 100mL / L~180mL / L, tin methanesulfonate 100mL / L~170mL / L, 180 additive 20mL / L~40mL / L, 180 auxiliary agent 20mL / L~40mL / L;

[0008] The 180 additive composition is: 25.0% to 35.0% methanol, 1.0% to 5.0% 2-methyl-2-acrylic acid, 0.1% to <1.0% 4-phenyl-3-butene-2-one, and the balance is water;

[0009] The auxiliary agent 180 is composed of 10.0% to 20.0% of polyalkylene glycol and 80% to 90% of water.

[0010] As preferred embodiments of the present invention, the high-density punching tinned copper strip electroplating solution comprises:

[0011] Methanesulfonic acid 120mL / L~160mL / L, tin methanesulfonate 125mL / L~145mL / L, 180 additive 25mL / L~35mL / L, 180 auxiliary agent 25mL / L~35mL / L.

[0012] As preferred embodiments of the present invention, the high-density punching tinned copper strip electroplating solution comprises:

[0013] Methanesulfonic acid 140mL / L, tin methanesulfonate 135mL / L, 180 additive 30mL / L, 180 auxiliary agent 30mL / L.

[0014] The embodiment of the present invention further provides a method for processing a high-density punched tinned copper strip, the method using any one of the above-mentioned sets of high-density punched tinned copper strip electroplating solutions, the steps are as follows:

[0015] S1. Punching: Use a high-speed punching machine to punch holes on the copper strip;

[0016] S2. Degreasing: The punched copper strip is subjected to cation-cation cross electrolytic degreasing in the degreasing liquid to remove stains and deposits on the surface of the punched copper strip and discharge hydrogen that has penetrated into the metal;

[0017] S3, surface activation: firstly, the degreased punching copper strip is washed with deionized water for the first time, and then the surface is activated with methanesulfonic acid liquid after the first washing;

[0018] S4. Tin plating: first use deionized water to wash the punched copper strip after surface activation for the second time, and then quickly enter the electroplating tank with a total length of 8m for tin plating. The electroplating solution in the electroplating tank is the above-mentioned high-density punched tin-plated copper strip electroplating solution. The electroplating temperature is 5℃~30℃. During electroplating, the pure metal tin ball is used as the anode and the punched copper strip is used as the cathode. The moving speed of the punched copper strip is 5m / min~20m / min, and the current distribution is 2Ah / dm 2 ~4Ah / dm 2 , the control voltage is 4V~10V;

[0019] S5, washing and drying: After the electroplating is completed, the punched copper strip is washed for the third time and then dried to obtain a high-density punched tinned copper strip.

[0020] As some embodiments of the present invention, the thickness of the copper strip in step S1 is 0.1 mm, and the surface is required to be flat after punching.

[0021] As some embodiments of the present invention, in step S2, the degreasing liquid is a sodium hydroxide solution with a concentration of 50 g / L to 90 g / L, the degreasing temperature is 40° C. to 70° C., and the degreasing current is 70A to 90A.

[0022] As some embodiments of the present invention, in step S3, 5% to 10% methanesulfonic acid liquid is used for surface activation.

[0023] As some embodiments of the present invention, in step S4, the electroplating temperature is 10°C to 25°C, the punching copper belt moving speed is 8m / min to 15m / min, and the current distribution is 3Ah / dm 2 , the voltage is 5V~7V.

[0024] As preferred embodiments of some embodiments of the present invention, in step S4, the electroplating temperature is 15° C., the moving speed of the punching copper strip is 10 m / min, and the voltage is 6V.

[0025] As some embodiments of the present invention, in step S5, the oven temperature is set to 150°C during drying.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] In the electroplating solution of the present invention, polyalkylene glycol is used to replace antioxidants, chromium-containing passivation products or cyanide and the like in the traditional electroplating solution, so that the electroplating solution is more environmentally friendly and safe. A small amount of methanol and relatively high content of methanesulfonic acid and tin methanesulfonate are added to the electroplating solution, so that during the electroplating process, methanesulfonic acid continuously generates tin methanesulfonate at the positive electrode of the pure metal tin ball, and the tin methanesulfonate in the solution continuously plates tin on the surface of the negative electrode perforated copper strip to generate new methanesulfonic acid, so that the tin plating system is in a dynamic equilibrium process. The electroplating solution is initially configured with a certain concentration of tin methanesulfonate, so that sufficient tin elements are electroplated on the surface of the perforated copper strip in the initial stage of electroplating. Because polyalkylene glycol and methanol do not participate in the electroplating reaction process, and will not gather near the negative electrode perforated copper belt, therefore, although the electroplating solution will be partially consumed as the product is taken out, only the total amount of the electroplating solution is reduced, and the content of its various components remains basically unchanged, so that the electroplating tin process is continuous and stable, and a uniform tin-plating layer of 1.5μm to 3.0μm is formed on the surface of the perforated copper belt by quickly transferring the anode tin to the cathode perforated copper belt, and the plating layer is well combined with the substrate, the plating layer is finely crystallized, without pinholes and pitting, and is not oxidized or blackened.

[0028] In the processing of high-density perforated tin-plated copper strips, the temperature of the electroplating process is controlled at about 15°C, which ensures the normal and stable operation of the electroplating on the one hand, and avoids the volatilization of substances in the electroplating solution on the other hand, ensuring the balance of the substance content in the electroplating solution. The electrolytic positive and negative cross-level degreasing method is adopted to quickly remove the stains on the surface of the perforated copper strip through cathode degreasing, and then the positive and negative poles are changed so that the cathode becomes the anode, and the hydrogen that penetrates into the metal is removed in a short time, and the deposition on the surface of the perforated copper strip is dissolved to obtain a clean surface. Then the surface of the perforated copper strip is activated, so that it is easier to adhere to tin on its surface during electroplating, enhance the bonding force between the coating and the substrate, improve the flatness of the coating, and make the coating dense. After the surface activation, the perforated copper strip is quickly put into the electroplating tank to avoid contamination of other substances on the activated surface and avoid deactivation of the activated surface. DETAILED DESCRIPTION

[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the technical scheme in the specific implementation mode of the present invention is clearly and completely described below to further illustrate the present invention. Obviously, the specific implementation mode described is only a part of the implementation mode of the present invention, rather than all styles.

[0030] It should be noted that: during the tinning process of the perforated copper strip, the thickness of the perforated copper strip has almost no effect on the implementation of the tinning process. Therefore, in the embodiment of the present invention, only a 1mm thick perforated copper strip is used as the substrate for the experiment. It should be understood that the electroplating solution and processing method of the present invention also have the same or similar effects when used for copper strips of other thicknesses. The purpose of using a special mold and a specific punching speed to punch the copper strip in step S1 of the embodiment of the present invention is to meet the requirements of the porosity and active material filling amount of subsequent products used in nickel-zinc batteries. It does not affect the final effect and performance of the tinning process. It should be understood that the present invention has the same or similar effects when used on products such as non-porous copper strips, perforated copper strips and perforated copper strips.

[0031] Example 1: In this example, the composition of the high-density punching tinned copper strip electroplating solution is:

[0032] Methanesulfonic acid 140mL / L, tin methanesulfonate 135mL / L, 180 additive 30mL / L, 180 auxiliary agent 30mL / L;

[0033] The 180 additive is VALTEK 180 additive with SDS number 10106871 produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 25.0% to 35.0% methanol (CASRN: 67-56-1), 1.0% to 5.0% 2-methyl-2-acrylic acid (CASRN: 79-41-4), 0.1% to <1.0% 4-phenyl-3-butene-2-one (CASRN: 122-57-6), and the balance is water (CASRN: 7732-18-5);

[0034] The 180 auxiliary agent adopts VALTEK 180 auxiliary agent produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 10.0% to 20.0% of polyalkylene glycol and 80% to 90% of water (CASRN: 7732-18-5).

[0035] The specific processing method and process parameters in this embodiment are as follows:

[0036] S1. Punching: Use a high-speed punching machine to punch holes in a copper plate with a thickness of 0.1 mm using a special die. Use a specific punching speed to make the surface of the copper strip smooth after punching, increase its opening rate, and facilitate subsequent processing to increase the filling amount of active substances;

[0037] S2. Degreasing: Use a sodium hydroxide solution with a concentration of 60g / L as the degreasing liquid to perform cation-cation cross electrolytic degreasing on the punching copper strip. The degreasing temperature is 55°C and the degreasing current is 80A to remove stains and deposits on the surface of the punching copper strip and discharge hydrogen that has penetrated into the metal.

[0038] S3, surface activation: firstly, the degreased punching copper strip is washed with deionized water for the first time, and then, 7% methanesulfonic acid liquid is used for surface activation after the first washing;

[0039] S4. Tin plating: First, use deionized water to wash the perforated copper strip for the second time after the surface activation is completed. After the second washing, quickly enter the electroplating tank with a total length of 8m for tin plating. The composition of the electroplating solution in the electroplating tank is as mentioned above. The electroplating temperature is 15°C. During electroplating, the pure metal tin ball is used as the anode and the perforated copper strip is used as the cathode. The moving speed of the perforated copper strip is 10m / min, and the current distribution is 3Ah / dm 2 , the control voltage is 6V;

[0040] S5, washing and drying: After the electroplating is completed, the punched copper strip is washed for the third time, and then dried in an oven set at a temperature of 150° C. to obtain a high-density punched tinned copper strip.

[0041] The high-density punched tinned copper strip obtained in this embodiment was sampled for coating detection and gas evolution test analysis, and the results are shown in Table 1.

[0042] Example 2: In this example, the process is consistent with that in Example 1, except for the composition and content of the electrolyte. The composition of the high-density punched tinned copper strip electroplating solution in this example is:

[0043] Methanesulfonic acid 100mL / L, tin methanesulfonate 170mL / L, 180 additive 20mL / L, 180 auxiliary agent 40mL / L;

[0044] The 180 additive is VALTEK 180 additive with SDS number 10106871 produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 25.0% to 35.0% methanol, 1.0% to 5.0% 2-methyl-2-acrylic acid, 0.1% to <1.0% 4-phenyl-3-butene-2-one, and the balance is water;

[0045] The 180 auxiliary agent adopts VALTEK 180 auxiliary agent produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 10.0% to 20.0% of polyalkylene glycol and 80% to 90% of water.

[0046] The specific processing method and process parameters in this embodiment are as follows:

[0047] S1. Punching: Use a high-speed punching machine to punch holes in a copper plate with a thickness of 0.1 mm using a special die. Use a specific punching speed to make the surface of the copper strip smooth after punching, increase its opening rate, and facilitate subsequent processing to increase the filling amount of active substances;

[0048] S2. Degreasing: Use a sodium hydroxide solution with a concentration of 60g / L as the degreasing liquid to perform cation-cation cross electrolytic degreasing on the punching copper strip. The degreasing temperature is 55°C and the degreasing current is 80A to remove stains and deposits on the surface of the punching copper strip and discharge hydrogen that has penetrated into the metal.

[0049] S3, surface activation: firstly, the degreased punching copper strip is washed with deionized water for the first time, and then, 7% methanesulfonic acid liquid is used for surface activation after the first washing;

[0050] S4. Tin plating: First, use deionized water to wash the perforated copper strip for the second time after the surface activation is completed. After the second washing, quickly enter the electroplating tank with a total length of 8m for tin plating. The composition of the electroplating solution in the electroplating tank is as mentioned above. The electroplating temperature is 15°C. During electroplating, the pure metal tin ball is used as the anode and the perforated copper strip is used as the cathode. The moving speed of the perforated copper strip is 10m / min, and the current distribution is 3Ah / dm 2 , the control voltage is 6V;

[0051] S5, washing and drying: After the electroplating is completed, the punched copper strip is washed for the third time, and then dried in an oven set at a temperature of 150° C. to obtain a high-density punched tinned copper strip.

[0052] The high-density punched tinned copper strip obtained in this embodiment was sampled for coating detection and gas evolution test analysis, and the results are shown in Table 1.

[0053] Example 3: In this example, the process is consistent with that in Example 1, except for the composition and content of the electrolyte. The composition of the high-density punching tinned copper strip electroplating solution is:

[0054] Methanesulfonic acid 180mL / L, tin methanesulfonate 100mL / L, 180 additive 40mL / L, 180 auxiliary agent 20mL / L;

[0055] The 180 additive is VALTEK 180 additive with SDS number 10106871 produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 25.0% to 35.0% methanol, 1.0% to 5.0% 2-methyl-2-acrylic acid, 0.1% to <1.0% 4-phenyl-3-butene-2-one, and the balance is water;

[0056] The 180 auxiliary agent adopts VALTEK 180 auxiliary agent produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 10.0% to 20.0% of polyalkylene glycol and 80% to 90% of water.

[0057] The specific processing method and process parameters in this embodiment are as follows:

[0058] S1. Punching: Use a high-speed punching machine to punch holes in a copper plate with a thickness of 0.1 mm using a special die. Use a specific punching speed to make the surface of the copper strip smooth after punching, increase its opening rate, and facilitate subsequent processing to increase the filling amount of active substances;

[0059] S2. Degreasing: Use a sodium hydroxide solution with a concentration of 70g / L as the degreasing liquid to perform cation-cation cross electrolytic degreasing on the punching copper strip. The degreasing temperature is 55°C and the degreasing current is 80A to remove stains and deposits on the surface of the punching copper strip and discharge hydrogen that has penetrated into the metal.

[0060] S3, surface activation: firstly, the degreased punching copper strip is washed with deionized water for the first time, and then, 7% methanesulfonic acid liquid is used for surface activation after the first washing;

[0061] S4. Tin plating: First, use deionized water to wash the perforated copper strip for the second time after the surface activation is completed. After the second washing, quickly enter the electroplating tank with a total length of 8m for tin plating. The composition of the electroplating solution in the electroplating tank is as mentioned above. The electroplating temperature is 15°C. During electroplating, the pure metal tin ball is used as the anode and the perforated copper strip is used as the cathode. The moving speed of the perforated copper strip is 10m / min, and the current distribution is 3Ah / dm 2 , the control voltage is 6V;

[0062] S5, washing and drying: After the electroplating is completed, the punched copper strip is washed for the third time, and then dried in an oven set at a temperature of 150° C. to obtain a high-density punched tinned copper strip.

[0063] The high-density punched tinned copper strip obtained in this embodiment was sampled for coating detection and gas evolution test analysis, and the results are shown in Table 1.

[0064] Example 4: In this example, the composition and content of the electroplating solution are consistent with those in Example 1, except for the parameters of the electroplating process. The composition of the high-density punched tinned copper strip electroplating solution is:

[0065] Methanesulfonic acid 140mL / L, tin methanesulfonate 135mL / L, 180 additive 30mL / L, 180 auxiliary agent 30mL / L;

[0066] The 180 additive is VALTEK 180 additive with SDS number 10106871 produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 25.0% to 35.0% methanol, 1.0% to 5.0% 2-methyl-2-acrylic acid, 0.1% to <1.0% 4-phenyl-3-butene-2-one, and the balance is water;

[0067] The 180 auxiliary agent adopts VALTEK 180 auxiliary agent produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 10.0% to 20.0% of polyalkylene glycol and 80% to 90% of water.

[0068] The specific processing method and process parameters in this embodiment are as follows:

[0069] S1. Punching: Use a high-speed punching machine to punch holes in a copper plate with a thickness of 0.1 mm using a special die. Use a specific punching speed to make the surface of the copper strip smooth after punching, increase its opening rate, and facilitate subsequent processing to increase the filling amount of active substances;

[0070] S2. Degreasing: Use a sodium hydroxide solution with a concentration of 70g / L as the degreasing liquid to perform cation-cation cross electrolytic degreasing on the punching copper strip. The degreasing temperature is 55°C and the degreasing current is 80A to remove stains and deposits on the surface of the punching copper strip and discharge hydrogen that has penetrated into the metal.

[0071] S3, surface activation: firstly, the degreased punching copper strip is washed with deionized water for the first time, and then, 7% methanesulfonic acid liquid is used for surface activation after the first washing;

[0072] S4. Tin plating: First, use deionized water to wash the perforated copper strip after surface activation for the second time. After the second washing, quickly enter the electroplating tank with a total length of 8m for tin plating. The composition of the electroplating solution in the electroplating tank is as mentioned above. The electroplating temperature is 5°C. During electroplating, the pure metal tin ball is used as the anode and the perforated copper strip is used as the cathode. The moving speed of the perforated copper strip is 5m / min, and the current distribution is 2Ah / dm 2 , the control voltage is 4V;

[0073] S5, washing and drying: After the electroplating is completed, the punched copper strip is washed for the third time, and then dried in an oven set at a temperature of 150° C. to obtain a high-density punched tinned copper strip.

[0074] The high-density punched tinned copper strip obtained in this embodiment was sampled for coating detection and gas evolution test analysis, and the results are shown in Table 1.

[0075] Example 5: In this example, the composition and content of the electroplating solution are consistent with those in Example 1, except for the parameters of the electroplating process. The composition of the high-density punched tinned copper strip electroplating solution is:

[0076] Methanesulfonic acid 140mL / L, tin methanesulfonate 135mL / L, 180 additive 30mL / L, 180 auxiliary agent 30mL / L;

[0077] The 180 additive is VALTEK 180 additive with SDS number 10106871 produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 25.0% to 35.0% methanol, 1.0% to 5.0% 2-methyl-2-acrylic acid, 0.1% to <1.0% 4-phenyl-3-butene-2-one, and the balance is water;

[0078] The 180 auxiliary agent adopts VALTEK 180 auxiliary agent produced by Rohm and Haas Electronic Materials (Dongguan) Co., Ltd., and its specific composition is: 10.0% to 20.0% of polyalkylene glycol and 80% to 90% of water.

[0079] The specific processing method and process parameters in this embodiment are as follows:

[0080] S1. Punching: Use a high-speed punching machine to punch holes in a copper plate with a thickness of 0.1 mm using a special die. Use a specific punching speed to make the surface of the copper strip smooth after punching, increase its opening rate, and facilitate subsequent processing to increase the filling amount of active substances;

[0081] S2. Degreasing: Use a sodium hydroxide solution with a concentration of 70g / L as the degreasing liquid to perform cation-cation cross electrolytic degreasing on the punching copper strip. The degreasing temperature is 55°C and the degreasing current is 80A to remove stains and deposits on the surface of the punching copper strip and discharge hydrogen that has penetrated into the metal.

[0082] S3, surface activation: firstly, the degreased punching copper strip is washed with deionized water for the first time, and then, 7% methanesulfonic acid liquid is used for surface activation after the first washing;

[0083] S4. Tin plating: First, use deionized water to wash the perforated copper strip after surface activation for the second time. After the second washing, quickly enter the electroplating tank with a total length of 8m for tin plating. The composition of the electroplating solution in the electroplating tank is as mentioned above. The electroplating temperature is 30°C. During electroplating, the pure metal tin ball is used as the anode and the perforated copper strip is used as the cathode. The moving speed of the perforated copper strip is 20m / min, and the current distribution is 4Ah / dm 2 , the control voltage is 10V;

[0084] S5, washing and drying: After the electroplating is completed, the punched copper strip is washed for the third time, and then dried in an oven set at a temperature of 150° C. to obtain a high-density punched tinned copper strip.

[0085] The high-density punched tinned copper strip obtained in this embodiment was sampled for coating detection and gas evolution test analysis, and the results are shown in Table 1.

[0086] Comparative Example 1: The conventional tin plating solution formula used in this comparative example is: 40g / L~60g / L stannous sulfate; 40g / L~60g / L sulfuric acid; 30g / L~40g / L sodium phenolsulfonate; 1g / L~2g / L additives. The product is tin-plated under normal process conditions, and the product is sampled for coating detection and gas evolution test analysis. The test results are shown in Table 1.

[0087] Comparative Example 2: This comparative example is basically the same as Comparative Example 1, except that during the electroplating process, the plating solution is continuously replenished and purified, and the product samples are taken for coating detection and gas evolution test and analysis. The test results are shown in Table 1.

[0088] In the present invention, the testing principle of the gas evolution amount is: a micro-battery is formed in a glass bottle using impurities on the surface of zinc and tin layers (mainly iron and nickel) in a 30% KOH electrolyte. When the density of the tin coating is poor and there are many gaps on the surface, the metal impurities doped in the coating react electrochemically with zinc, and gas is precipitated on the electrode surface. In a sealed environment, the thrust of the gas pushes the paraffin oil into the plastic tube of the syringe, and the metal impurities can be measured from the amount of paraffin oil seeping out to facilitate the evaluation of the quality of the coating.

[0089] The gas evolution test method is as follows: the sample is cut into 15cm×3cm sheets along the length direction, washed with deionized water and then dried, the sample is placed in a drying tray, placed in a constant temperature oven at 200°C for 45 minutes, the tray is taken out, and cooled at room temperature.

[0090] Place the cooled sample in a 30mL glass bottle and add 5g of zinc powder to evenly distribute it at the bottom of the bottle; then add 20mL of 30% potassium hydroxide solution into the glass bottle, fill the remaining space of the glass bottle with paraffin oil, seal the rubber cover, then put the aluminum cover on the rubber cover and seal it with a sealer.

[0091] Remove the inner plastic core of the disposable syringe, tighten the needle, and then insert the syringe into the rubber cap (the needle must be fully inserted); apply the prepared AB glue to the joints between the needle and the bottle cap, the joints between the bottle cap and the glass bottle, and the gaps between the plastic cap and the aluminum cap. Start timing, record the liquid level on the syringe every 24 hours, record for 3 times in a row, and get the average value of the readings for 3 days, which is the gas evolution test data of the sample.

[0092] Table 1 Punching tinned copper strip performance test table

[0093] project Tin plating thickness (μm) Gas evolution (ml / day) Standard requirements 1.5～3.0 ≤0.6 Example 1 1.68 0.25 Example 2 1.67 0.29 Example 3 1.69 0.27 Example 4 1.66 0.31 Example 5 1.65 0.33 Comparative Example 1 1.50 0.73 Comparative Example 2 1.70 0.51

[0094] It can be seen from Table 1 that in the production process of common electroplating solutions, effective ingredients need to be continuously added and the electrolyte needs to be purified, otherwise the quality and performance of the product will be seriously affected. However, the coatings of the method implemented by the present invention are all qualified, and the gas evolution test shows that the coating density of the product of the present invention is significantly higher than that of the traditional process product, which shows that the technical advantages of the present invention are significant.

[0095] The above describes the main technical features and basic principles of the present invention and the related advantages. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the concept or basic features of the present invention. Therefore, no matter from which point of view, the above specific embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0096] In addition, it should be understood that although the present specification is described according to various implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A high-density punching tinned copper strip electroplating solution, characterized in that: include: Methanesulfonic acid 100mL / L~180mL / L, tin methanesulfonate 100mL / L~170mL / L, 180 additive 20mL / L~40mL / L, 180 auxiliary agent 20mL / L~40mL / L; The 180 additive composition is: 25.0% to 35.0% methanol, 1.0% to 5.0% 2-methyl-2-acrylic acid, 0.1% to <1.0% 4-phenyl-3-butene-2-one, and the balance is water; The auxiliary agent 180 is composed of 10.0% to 20.0% of polyalkylene glycol and 80% to 90% of water.

2. The high-density punching tinned copper strip electroplating solution according to claim 1, characterized in that: include: Methanesulfonic acid 120mL / L~160mL / L, tin methanesulfonate 125mL / L~145mL / L, 180 additive 25mL / L~35mL / L, 180 auxiliary agent 25mL / L~35mL / L.

3. A high-density punching tinned copper strip electroplating solution according to claim 2, characterized in that: include: Methanesulfonic acid 140mL / L, tin methanesulfonate 135mL / L, 180 additive 30mL / L, 180 auxiliary agent 30mL / L.

4. A method for processing a high-density punched tinned copper strip, characterized in that: The steps of this method are as follows: S1. Punching: Use a high-speed punching machine to punch holes on the copper strip; S2. Degreasing: The punched copper strip is then subjected to cation-cation cross electrolytic degreasing in the degreasing liquid to remove stains and deposits on the surface of the punched copper strip and discharge hydrogen that has penetrated into the metal; S3, surface activation: firstly, the degreased punching copper strip is washed with deionized water for the first time, and then the surface is activated with methanesulfonic acid liquid after the first washing; S4, tin plating: first use deionized water to wash the punched copper strip after surface activation for the second time, and then quickly enter the electroplating tank with a total length of 8m for tin plating. The electroplating solution in the electroplating tank is the high-density punched tin-plated copper strip electroplating solution described in any one of claims 1 to 3, the electroplating temperature is 5°C to 30°C, the pure metal tin ball is used as the anode, the punched copper strip is used as the cathode, the moving speed of the punched copper strip is 5m / min to 20m / min, and the current distribution is 2Ah / dm 2 ~4Ah / dm 2 , the control voltage is 4V~10V; S5, washing and drying: After the electroplating is completed, the punched copper strip is washed for the third time and then dried to obtain a high-density punched tinned copper strip.

5. The method for processing a high-density punched tinned copper strip according to claim 4, characterized in that: The thickness of the copper strip in step S1 is 0.1 mm, and the surface of the copper strip is flat after punching.

6. The method for processing a high-density punched tinned copper strip according to claim 4, characterized in that: In step S2, the degreasing liquid is a sodium hydroxide solution with a concentration of 30 g / L to 70 g / L, the degreasing temperature is 50° C. to 70° C., and the degreasing current is 70A to 90A.

7. The method for processing a high-density punched tinned copper strip according to claim 4, characterized in that: In step S3, 5% to 10% methanesulfonic acid liquid is used for surface activation.

8. The method for processing a high-density punched tinned copper strip according to claim 4, characterized in that: In step S4, the electroplating temperature is 10°C to 25°C, the punching copper belt moving speed is 8m / min to 15m / min, and the current distribution is 3Ah / dm 2 , the voltage is 5V~7V.

9. The method for processing a high-density punched tinned copper strip according to claim 8, characterized in that: In step S4, the electroplating temperature is 15°C, the punching copper belt moving speed is 10m / min, and the voltage is 6V.

10. The method for processing a high-density punched tinned copper strip according to claim 4, characterized in that: In step S5, the oven temperature is set to 150°C during drying.