High-efficiency tin stripping agent and preparation method thereof

Abstract

The present invention discloses a smokeless tin stripping agent, which is a mixed solution of an aqueous solution of a tin stripping active substance and hydrochloric acid, wherein the tin stripping active substance includes hydrogen peroxide, octanoyl hydroxamic acid and dodecylbenzene sulfonic acid, and the solvent is water. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:3-4. The tin stripping agent of the present invention has a good stripping effect on the tin on the PCB board, and the tin stripping operation can be carried out at room temperature, no heating treatment is required, the equipment requirements are relatively low, and the cost is saved. The tin stripping agent of the present invention avoids the components that are easy to produce toxic gases such as fluoride and nitric acid used in conventional tin stripping agents, and the hydrogen generated during the tin stripping process is more environmentally friendly, avoiding damage to the operator's body.

Description

Technical Field

[0001] The present invention relates to the technical field of tin stripping agent pharmaceuticals, and in particular to a high-efficiency tin stripping agent and a preparation method thereof. Background Art

[0002] PCB (Printed Circuit Board, Chinese name is printed circuit board, also known as printed circuit board) is an important electronic component, a support for electronic components, and a carrier for electrical connections of electronic components. In the process of printing circuit boards, the circuit pattern needs to be thickened with copper and then tinned. During etching, the circuit pattern is required to be protected as an etching resist. After the non-circuit part is etched away, the electroplated tin layer needs to be removed with tin stripping water. At present, the industry mainly uses a nitric acid system composed of high-concentration nitric acid and ferric nitrate to strip tin. The concentration of nitric acid is generally 20-25%. This type of stripping agent has complex ingredients and is difficult to prepare. Excessively high temperatures will also cause the nitric acid to decompose and produce a large amount of NO X Gas, which is harmful to employees. In addition, there is a type of tin stripping liquid used to strip the conductive rollers of various types of electroplating tinning units. For example, patent CN1619013 proposes an alkaline tin stripping agent, the main components of which include sodium hydroxide, lead acetate, sodium leadite, sodium nitrate, etc. Patent CN04060269 proposes an alkaline tin stripping agent, the main components of which include sodium hydroxide, m-nitrobenzoic acid, etc. These three tin stripping agents have weak oxidizing properties. If used to separate electronic components, the tin stripping speed is very slow. Summary of the invention

[0003] To this end, the present invention provides a high-efficiency tin stripping agent, which is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, wherein the tin stripping active substance includes hydrogen peroxide, octanoylhydroxamic acid and dodecylbenzenesulfonic acid, and the solvent is water.

[0004] Furthermore, the raw materials used to prepare the aqueous solution of the tin-stripping active substance are in the following ratio: hydrogen peroxide: octanoylhydroxamic acid: dodecylbenzenesulfonic acid: water = 300 mL: 0.8-1 g: 0.1 g: 1 L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water.

[0005] Furthermore, the mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin-stripping active substance and the hydrochloric acid is the aqueous solution of the tin-stripping active substance: hydrochloric acid = 1:3-4.

[0006] The present invention also discloses a method for preparing the above-mentioned efficient tin stripping agent. The tin stripping agent is prepared and used immediately, and the preparation steps are:

[0007] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid, dodecylbenzene sulfonic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring, and continuing to stir for 20 to 30 minutes after the addition is completed, to obtain an aqueous solution of the tin-stripping active substance;

[0008] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 to 40 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 to 30 minutes to obtain the tin-stripping agent.

[0009] The present invention also discloses a method for using the above-mentioned tin stripping agent, and the process is: immersing a PCB board to be stripped of tin in the tin stripping agent at room temperature for 90 to 120 seconds to complete the tin stripping of the PCB board.

[0010] The mechanism of the technical solution of the present invention is that the present invention utilizes concentrated hydrochloric acid to react with metal tin on the PCB board to undergo an oxidation-reduction reaction, dissolves the metal tin into a solution, thereby achieving the technical effect of tin stripping, wherein the reaction equation is Sn+2HCl=SnCl2+H2↑, and then the divalent tin ions are oxidized into tetravalent tin ions by hydrogen peroxide, thereby promoting the forward movement of the above reaction equation and increasing the dissolution rate of the metal tin; at the same time, the tetravalent tin ions are more likely to chelate with octanoyl hydroxamic acid to form a stable compound and remain in the solution, thereby preventing the tin ions in the solution from being replaced and reduced by the more active metal on the PCB board again; at the same time, the addition of octanoyl hydroxamic acid is beneficial to promoting the wettability of the tin stripping agent and the alloy on the PCB board, thereby making the alloy more likely to react with concentrated hydrochloric acid to dissolve the tin, and dodecylbenzenesulfonic acid is used to improve the oxidizability of hydrogen peroxide and accelerate the efficiency of converting the divalent tin ions into tetravalent tin ions.

[0011] The beneficial effects of the present invention are as follows: the tin stripping agent of the present invention has a good stripping effect on the tin on the PCB board, and the tin stripping operation can be performed at room temperature, no heating treatment is required, the equipment requirements are low, and the cost is saved. The tin stripping agent of the present invention avoids the components such as fluoride and nitric acid used in conventional tin stripping agents that are prone to produce toxic gases, and the hydrogen generated during the tin stripping process is more environmentally friendly, avoiding damage to the operator's body. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the embodiments.

[0013] Example 1

[0014] A highly efficient tin stripping agent, the tin stripping agent is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes hydrogen peroxide, octanoyl hydroxamic acid and dodecylbenzene sulfonic acid, and the solvent is water. The amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is hydrogen peroxide: octanoyl hydroxamic acid: dodecylbenzene sulfonic acid: water = 300mL: 0.8g: 0.1g: 1L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:3.

[0015] The preparation method of the above-mentioned high-efficiency tin stripping agent, the tin stripping agent is prepared and used immediately, and the preparation steps are:

[0016] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid, dodecylbenzene sulfonic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring, and continuing to stir for 20 minutes after the addition is completed, to obtain an aqueous solution of the tin-stripping active substance;

[0017] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 minutes to obtain the tin-stripping agent.

[0018] The method for using the above-mentioned tin stripping agent is as follows: immerse the PCB board to be stripped (a test board, in which a 10 μm tin layer is plated on the copper surface) in the tin stripping agent for 90 seconds at room temperature to complete the tin stripping of the PCB board. Observe the dissolution of the tin layer on the surface of the test board, as shown in Table 1.

[0019] Example 2

[0020] A highly efficient tin stripping agent, the tin stripping agent is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes hydrogen peroxide, octanoyl hydroxamic acid and dodecylbenzene sulfonic acid, and the solvent is water. The amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is hydrogen peroxide: octanoyl hydroxamic acid: dodecylbenzene sulfonic acid: water = 300mL: 0.9g: 0.1g: 1L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:3.

[0021] The preparation method of the above-mentioned high-efficiency tin stripping agent, the tin stripping agent is prepared and used immediately, and the preparation steps are:

[0022] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid, dodecylbenzene sulfonic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring, and continuing to stir for 20 minutes after the addition is completed, to obtain an aqueous solution of the tin-stripping active substance;

[0023] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 minutes to obtain the tin-stripping agent.

[0024] The method for using the above-mentioned tin stripping agent is as follows: immerse the PCB board to be stripped (a test board, in which a 10 μm tin layer is plated on the copper surface) in the tin stripping agent for 90 seconds at room temperature to complete the tin stripping of the PCB board. Observe the dissolution of the tin layer on the surface of the test board, as shown in Table 1.

[0025] Example 3

[0026] A highly efficient tin stripping agent, the tin stripping agent is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes hydrogen peroxide, octanoyl hydroxamic acid and dodecylbenzene sulfonic acid, and the solvent is water. The amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is hydrogen peroxide: octanoyl hydroxamic acid: dodecylbenzene sulfonic acid: water = 300mL: 0.9g: 0.1g: 1L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:4.

[0027] The preparation method of the above-mentioned high-efficiency tin stripping agent, the tin stripping agent is prepared and used immediately, and the preparation steps are:

[0028] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid, dodecylbenzene sulfonic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring, and continuing to stir for 20 minutes after the addition is completed, to obtain an aqueous solution of the tin-stripping active substance;

[0029] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 minutes to obtain the tin-stripping agent.

[0030] The method for using the above-mentioned tin stripping agent is as follows: immerse the PCB board to be stripped (a test board, in which a 10 μm tin layer is plated on the copper surface) in the tin stripping agent for 90 seconds at room temperature to complete the tin stripping of the PCB board. Observe the dissolution of the tin layer on the surface of the test board, as shown in Table 1.

[0031] Example 4

[0032] A highly efficient tin stripping agent, the tin stripping agent is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes hydrogen peroxide, octanoyl hydroxamic acid and dodecylbenzene sulfonic acid, and the solvent is water. The amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is hydrogen peroxide: octanoyl hydroxamic acid: dodecylbenzene sulfonic acid: water = 300mL: 1g: 0.1g: 1L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:4.

[0033] The preparation method of the above-mentioned high-efficiency tin stripping agent, the tin stripping agent is prepared and used immediately, and the preparation steps are:

[0034] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid, dodecylbenzene sulfonic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring, and continuing to stir for 20 minutes after the addition is completed, to obtain an aqueous solution of the tin-stripping active substance;

[0035] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 minutes to obtain the tin-stripping agent.

[0036] The method for using the above-mentioned tin stripping agent is as follows: immerse the PCB board to be stripped (a test board, in which a 10 μm tin layer is plated on the copper surface) in the tin stripping agent for 90 seconds at room temperature to complete the tin stripping of the PCB board. Observe the dissolution of the tin layer on the surface of the test board, as shown in Table 1.

[0037] Comparative Example 1

[0038] A tin stripping agent for comparison, the tin stripping agent is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes octanoyl hydroxamic acid and dodecylbenzene sulfonic acid, and the solvent is water. The amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is octanoyl hydroxamic acid: dodecylbenzene sulfonic acid: water = 0.9g: 0.1g: 1.3L. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:4.

[0039] The preparation method of the above-mentioned tin stripping agent, the tin stripping agent is prepared and used immediately, and the preparation steps are:

[0040] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid, dodecylbenzene sulfonic acid and water to form a mixed solution, stirring the mixed solution for 20 minutes, and obtaining an aqueous solution of the tin-stripping active substance described in this comparative example;

[0041] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 minutes to obtain the tin-stripping agent.

[0042] The method for using the above-mentioned tin stripping agent is as follows: immerse the PCB board to be stripped (a test board, in which a 10 μm tin layer is plated on the copper surface) in the tin stripping agent for 90 seconds at room temperature to complete the tin stripping of the PCB board. Observe the dissolution of the tin layer on the surface of the test board, as shown in Table 1.

[0043] Comparative Example 2

[0044] A tin stripping agent for comparison, the tin stripping agent is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes hydrogen peroxide and dodecylbenzenesulfonic acid, and the solvent is water. The amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is hydrogen peroxide: dodecylbenzenesulfonic acid: water = 300mL: 0.1g: 1L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:4.

[0045] The preparation method of the above-mentioned tin stripping agent, the tin stripping agent is prepared and used immediately, and the preparation steps are:

[0046] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing dodecylbenzenesulfonic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring, and continuing to stir for 20 minutes after the addition is completed, to obtain an aqueous solution of the tin-stripping active substance;

[0047] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 minutes to obtain the tin-stripping agent.

[0048] The method for using the above-mentioned tin stripping agent is as follows: immerse the PCB board to be stripped (a test board, in which a 10 μm tin layer is plated on the copper surface) in the tin stripping agent for 90 seconds at room temperature to complete the tin stripping of the PCB board. Observe the dissolution of the tin layer on the surface of the test board, as shown in Table 1.

[0049] Comparative Example 3

[0050] A tin stripping agent for comparison, the tin stripping agent is a mixture of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes hydrogen peroxide and octanoyl hydroxamic acid, and the solvent is water. The amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is hydrogen peroxide: octanoyl hydroxamic acid: water = 300mL: 0.9g: 1L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water. The mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:4.

[0051] The preparation method of the above-mentioned tin stripping agent, the tin stripping agent is prepared and used immediately, and the preparation steps are:

[0052] (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring, and continuing to stir for 20 minutes after the addition is completed, to obtain an aqueous solution of the tin-stripping active substance;

[0053] (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 minutes to obtain the tin-stripping agent.

[0054] The method for using the above-mentioned tin stripping agent is as follows: immerse the PCB board to be stripped (a test board, in which a 10 μm tin layer is plated on the copper surface) in the tin stripping agent for 90 seconds at room temperature to complete the tin stripping of the PCB board. Observe the dissolution of the tin layer on the surface of the test board, as shown in Table 1.

[0055] Table 1

[0056] Experimental Group Tin layer on the test board surface Example 1 The tin on the surface is completely removed, and the exposed copper layer is bright Example 2 The tin on the surface is completely removed, and the exposed copper layer is bright Example 3 The tin on the surface is completely removed, and the exposed copper layer is bright Example 4 The tin on the surface is completely removed, and the exposed copper layer is bright Comparative Example 1 Some surfaces are still covered with tin, and the tin removal is incomplete Comparative Example 2 Some surfaces are still covered with tin, and the tin removal is incomplete Comparative Example 3 Some surfaces are still covered with tin, and the tin removal is incomplete

[0057] As shown in Table 1, the tin stripping agent of the present invention has a good stripping effect on the tin on the PCB board, and the tin stripping operation can be performed at room temperature, no heating treatment is required, the equipment requirements are low, and the cost is saved. The tin stripping agent of the present invention avoids the components such as fluoride and nitric acid used in conventional tin stripping agents that are prone to produce toxic gases, and the hydrogen generated during the tin stripping process is more environmentally friendly, avoiding damage to the operator's body.

[0058] The technical solution provided by the present invention is introduced in detail above. For those skilled in the art, according to the concept of the embodiments of the present invention, there may be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A highly efficient tin stripping agent, characterized in that: The tin stripping agent is a mixed solution of an aqueous solution of a tin stripping active substance and hydrochloric acid, the tin stripping active substance includes hydrogen peroxide, octanoylhydroxamic acid and dodecylbenzenesulfonic acid, and the solvent is water; the amount ratio of the raw materials used to prepare the aqueous solution of the tin stripping active substance is hydrogen peroxide: octanoylhydroxamic acid: dodecylbenzenesulfonic acid: water = 300mL: 0.8~1g: 0.1g: 1L; the mass percentage of the solute in the hydrogen peroxide is 30%, and the solvent is water; the mass percentage of the solute in the hydrochloric acid is 36%, and the mixed volume ratio of the aqueous solution of the tin stripping active substance and the hydrochloric acid is the aqueous solution of the tin stripping active substance: hydrochloric acid = 1:3~4.

2. The method for preparing a highly efficient tin stripping agent according to claim 1, characterized in that: The desoldering agent is prepared and used immediately, and the preparation steps are: (1) weighing each raw material according to the amount ratio of the raw materials, then mixing octanoyl hydroxamic acid, dodecylbenzene sulfonic acid and water to form a mixed solution, stirring the mixed solution, and then adding the hydrogen peroxide to the mixed solution under stirring. After the addition is completed, continue stirring for 20 to 30 minutes to obtain an aqueous solution of the tin-stripping active substance; (2) The aqueous solution of the tin-stripping active substance is allowed to stand at room temperature for 30 to 40 minutes, and then the aqueous solution of the tin-stripping active substance is stirred, and the hydrochloric acid is added during the stirring process. After the addition is completed, stirring is continued for 20 to 30 minutes to obtain the tin-stripping agent.

3. The method for using the tin stripping agent according to claim 1, characterized in that: The process is as follows: immersing the PCB board to be detinned in the detinning agent at room temperature for 90 to 120 seconds to complete the detinning of the PCB board.