A desmear water additive, and a method of making and using the same

Abstract

The application discloses a kind of tin stripping water additives and preparation method and use method thereof.The preparation method includes: under the condition of continuous stirring, 8-hydroxyquinoline, phenol sulfonic acid, ethanolamine, urea, sulfuric acid are added to water, finally, constant volume with water, tin stripping water additive is obtained.The application is applicable to the tin stripping process of sulfuric acid / hydrogen peroxide system, tin layer can be effectively stripped, stripping speed is fast, copper biting rate is low, copper layer is bright, and process requirements can be met;The additive can effectively prevent the ineffective decomposition of hydrogen peroxide;The additive does not contain fluoride and nitric acid;The nitrogen content of washing tank water and post-washing water is low, which can effectively alleviate the environmental protection pressure of total nitrogen and ammonia nitrogen emission standard faced by printed circuit board factory wastewater treatment station.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of printed circuit board processing, and particularly relates to a preparation method of a desmear solution and application thereof. BACKGROUND

[0002] In the process of printed circuit board processing, in order to protect the pattern line from being etched off when etching after pattern plating, a layer of tin is plated on the pattern line as an etching resist. When etching is completed, the desmear solution is used to remove the layer of tin.

[0003] At present, the desmear solution can be classified into three types according to the main components: ① fluoride type desmear solution composed of hydrofluoric acid, fluoride and hydrogen peroxide; ② nitric acid type desmear solution composed of nitric acid, ferric nitrate and additives; and ③ alkyl sulfonic acid type desmear solution composed of alkyl sulfonic acid and nitric acid. Among them, the nitric acid desmear solution is the most commonly used desmear solution in the industry. The fluoride type desmear solution has been gradually eliminated because the fluoride has strong toxicity, the waste liquid is difficult to treat, and the insulating layer of the circuit board is corroded. The nitric acid concentration of the nitric acid type desmear solution is generally 20-50%, which has the characteristics of fast tin stripping speed and high desmear capacity. However, the nitric acid type desmear solution has many defects and cannot meet the increasingly strict requirements of printed circuit board enterprises on environmental indicators and economic indicators. Specifically, the nitric acid has strong oxidizing property, and the nitric acid stripping process will decompose to produce toxic nitrogen oxide gas, which will bring great harm to the environment and the operators on site. The system is seriously corroded to the copper layer, and the general copper etching rate is about 2 microns per minute. If not properly controlled, it is easy to cause the line to become thin and be scrapped. In addition, the high concentration of nitric acid generates a large amount of heat during the stripping process, which makes the stripping solution rise steadily. The divalent tin ions in the solution are easily oxidized to form white stannate precipitate, which blocks the device nozzle and affects the process stability. The alkyl sulfonic acid type desmear solution is similar to the nitric acid type desmear solution, and the difference is that the concentration of nitric acid is lower, generally less than 15%, which reduces the harm to the equipment and the environment. However, the addition of organic sulfonic acid greatly increases the cost of the desmear solution. The alkyl sulfonic acid type desmear solution and the nitric acid type desmear solution both produce toxic gas and seriously corrode the copper layer, and the waste water treatment is difficult. SUMMARY

[0004] In view of the above problems, the present application aims to provide a preparation method of a desmear water additive and application thereof, which is suitable for a sulfuric acid-hydrogen peroxide system, and the sulfuric acid-hydrogen peroxide system desmear solution prepared by using the desmear water additive of the present application can achieve the purpose of quickly removing the tin plating layer, the desmear process does not produce toxic gas, the etching rate of copper is less than 0.1 microns / minute at the minimum, the copper surface is basically not bitten, and the copper surface is bright; meanwhile, the desmear solution does not contain nitric acid and fluorides, effectively reducing the pollution to the environment, the nitrogen content of the tank washing water and the post-washing water is low, effectively relieving the sewage treatment pressure of the waste water treatment station of the circuit board factory, and facilitating the sufficient response measures of the circuit board factory under the condition that the national total nitrogen and ammonia nitrogen environmental protection standards are continuously tightened.

[0005] The object of the present application is achieved by the following technical solutions:

[0006] The present application provides a preparation method of a desmear water additive, comprising the following steps:

[0007] Under the condition of continuous stirring, 8-hydroxyquinoline, phenol sulfonic acid, ethanolamine, urea and sulfuric acid are added into water, and finally water is used for constant volume, to obtain the desmear water additive.

[0008] Further, the mass of 8-hydroxyquinoline added in each liter of the desmear water additive is 25-35g.

[0009] Further, the volume of phenol sulfonic acid added in each liter of the desmear water additive is 40-60mL.

[0010] Further, the volume of ethanolamine added in each liter of the desmear water additive is 10-30mL.

[0011] Further, the mass of urea added in each liter of the desmear water additive is 5-20g.

[0012] Further, the volume of sulfuric acid added in each liter of the desmear water additive is 100-150mL.

[0013] The present application provides the desmear water additive prepared by the preparation method.

[0014] The present application also provides that the desmear water additive is suitable for the desmear process of a sulfuric acid / hydrogen peroxide system.

[0015] Further, the desmear water additive needs to be used with sulfuric acid-hydrogen peroxide, and the composition of the sulfuric acid-hydrogen peroxide system desmear water is as follows:

[0016] In each liter of the sulfuric acid-hydrogen peroxide system desmear water, 450-550mL of sulfuric acid (50% mass percentage concentration) and 3-7mL of hydrogen peroxide (50% mass percentage concentration) are added, and 50-150mL of the desmear water additive is added.

[0017] The tin stripping rate of copper is determined by the following method:

[0018] (1) Take a 4cm x 4cm double-sided copper-clad plate or tin plate, and record the area as s (cm 2 ), and place it in a forced air dryer at 105°C for 30 minutes, then move it to a drying box to cool to room temperature, and weigh it using an analytical balance, and record the weight as w0 (g), and reserve it for use;

[0019] (2) Soak the dried copper-clad plate or tin plate in the tin stripping water, and record the soaking time as t (min);

[0020] (3) After stripping, wash the copper-clad plate or tin plate with water, and place it in a forced air dryer at 105°C for 30 minutes, then move it to a drying box to cool to room temperature, and weigh it using an analytical balance, and record the weight as w1 (g);

[0021] (4) The stripping rate is calculated by the following formula:

[0022]

[0023] ρ is the density of tin or copper, and the unit is (g / cm 3 ).

[0024] The technical scheme of the present application can achieve the following beneficial effects:

[0025] 1. The tin stripping rate of the sulfuric acid-hydrogen peroxide system tin stripping water prepared by using the tin stripping water additive of the present application can reach more than 10 microns per minute, and is not affected by temperature.

[0026] 2. The copper stripping rate of the sulfuric acid-hydrogen peroxide system tin stripping water prepared by using the tin stripping water additive of the present application is less than 0.1 micron per minute at an operating temperature of 25°C, the copper layer is bright, and the copper stripping rate can be adjusted by temperature and hydrogen peroxide usage.

[0027] 3. After replacing the nitric acid stripping system with the sulfuric acid / hydrogen peroxide stripping system, the stripping effect is good, and can meet the relevant requirements of actual production.

[0028] 4. One of the main sources of ammonia nitrogen in the sewage treatment station of a printed circuit board factory is the washing water and post-washing water of the tin stripping tank, and the use of the sulfuric acid / hydrogen peroxide stripping system can effectively alleviate the pressure on the ammonia nitrogen treatment of the sewage treatment station.

[0029] 5. The use of the sulfuric acid / hydrogen peroxide stripping system can eliminate the generation of toxic gases such as nitrogen dioxide, improve the workshop environment, and contribute to the health of employees.

[0030] 6、From the development of the circuit board factory and environmental protection policy, the sulfuric acid / hydrogen peroxide stripping system is introduced into the graphic plating line, which is beneficial to protect the health of employees, protect the environment, and realize clean production of enterprises. Also, it is convenient to cope with the tightening standards of ammonia nitrogen environmental protection in the subsequent wastewater station.

[0031] 7、The tin stripping water additive of the application can effectively prevent the decomposition of hydrogen peroxide, is suitable for a sulfuric acid-hydrogen peroxide system, and the tin stripping water prepared by using the tin stripping water additive can achieve the purpose of quickly stripping the tin coating, while the tin stripping water does not contain nitric acid and fluorides, effectively reduces the pollution to the environment, and the nitrogen content of the tank water and the post-washing water is low, effectively alleviates the sewage treatment pressure of the circuit board factory wastewater treatment station, and facilitates the circuit board factory to have sufficient measures to cope with the tightening standards of total nitrogen and ammonia nitrogen environmental protection. DETAILED DESCRIPTION

[0032] In order to better understand the application, the application will be further described in detail below in combination with examples, but the scope of protection claimed by the application is not limited to the scope indicated by the examples.

[0033] Example 1

[0034] Preparation of the tin stripping water additive: under the condition of continuous stirring, 8-hydroxyquinoline 25 g, phenol sulfonic acid 40 mL, ethanol amine 30 mL, urea 5 g, sulfuric acid (mass percentage concentration is 50%) is 100 mL, and finally pure water is used to constant volume to 1 L, and the tin stripping water additive is obtained.

[0035] Application Example 1

[0036] Preparation of the sulfuric acid-hydrogen peroxide system tin stripping water: under the condition of continuous stirring, 500 mL of sulfuric acid (mass percentage concentration is 50%) is added to 100 mL of pure water, 5 mL of hydrogen peroxide (mass percentage concentration is 50%), 100 mL of the tin stripping water additive prepared in Example 1, and finally pure water is used to constant volume to 1 L.

[0037] The sulfuric acid-hydrogen peroxide system tin stripping water prepared according to the above application example 1 is used to treat the plated board under the condition of 25℃, the tin layer of the plated board is about 6 microns, the copper layer is about 52 microns, and the tin stripping is performed by soaking and swinging for 50 seconds.

[0038] The tin stripping copper rate is measured by the method as described above.

[0039] The tin stripping rate is: the tin stripping rate at 15℃, 20℃, 25℃ and 30℃ is 8 microns / minute.

[0040] The copper removal rate is: 0.3 microns / min at 30°C; 0.08 microns / min at 25°C; 0.06 microns / min at 20°C; and 0.02 microns / min at 15°C.

[0041] The concentration of hydrogen peroxide in the sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 1 does not change after the water is left to stand for 10 days.

[0042] Nitrogen content test: ① Tin removal water additive: 9.61 g / L; ② Tin removal tank working solution: 0.80 g / L.

[0043] Application Example 2

[0044] Preparation of sulfuric acid-hydrogen peroxide system tin removal water: 450 mL of sulfuric acid (50% by mass), 3 mL of hydrogen peroxide (50% by mass), and 50 mL of the tin removal water additive prepared in Example 1 were added to 100 mL of pure water under continuous stirring, and then the volume was made up to 1 L with pure water.

[0045] The sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 2 above was used to treat a strike plate at 25°C, the strike plate having a tin layer of about 6 microns and a copper layer of about 52 microns, and the strike plate was immersed and oscillated for 80 seconds to remove the tin.

[0046] The tin removal rate was measured by the method described above.

[0047] The tin removal rate is: 5 microns / min at 20°C, 25°C, and 30°C.

[0048] The copper removal rate is: 0.2 microns / min at 30°C; 0.06 microns / min at 25°C; and 0.03 microns / min at 20°C.

[0049] The concentration of hydrogen peroxide in the sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 1 does not change after the water is left to stand for 10 days.

[0050] Nitrogen content test: ① Tin removal water additive: 9.61 g / L; ② Tin removal tank working solution: 0.42 g / L.

[0051] Application Example 3

[0052] Preparation of sulfuric acid-hydrogen peroxide system tin removal water: 550 mL of sulfuric acid (50% by mass), 7 mL of hydrogen peroxide (50% by mass), and 150 mL of the tin removal water additive prepared in Example 1 were added to 100 mL of pure water under continuous stirring, and then the volume was made up to 1 L with pure water.

[0053] The tin stripping solution prepared in the above application example 3 was used to treat the plating assistant board at 25℃, the tin layer of the plating assistant board was about 6 microns, the copper layer was about 52 microns, and the tin was stripped for 30 seconds by immersion and swing.

[0054] The tin stripping rate was measured by the method described above

[0055] The tin stripping rate was 12 microns / minute at 20℃, 25℃ and 30℃.

[0056] The copper stripping rate was 0.35 microns / minute at 30℃, 0.09 microns / minute at 25℃ and 0.04 microns / minute at 20℃.

[0057] The concentration of hydrogen peroxide in the tin stripping solution prepared in application example 3 did not change after being placed for 10 days.

[0058] Nitrogen content test: ① Tin stripping solution additive: 9.61 g / L; ② Tin stripping tank working solution: 0.98 g / L.

[0059] Example 2

[0060] Preparation of tin stripping solution additive: under continuous stirring, 30 g of 8-hydroxyquinoline, 50 mL of phenol sulfonic acid, 20 mL of ethanolamine, 15 g of urea, 125 mL of sulfuric acid (50% by mass) were added to 500 mL of pure water, and finally the volume was made up to 1 L with pure water to obtain the tin stripping solution additive.

[0061] Application example 4

[0062] Preparation of sulfuric acid-hydrogen peroxide system tin stripping solution: under continuous stirring, 500 mL of sulfuric acid (50% by mass), 5 mL of hydrogen peroxide (50% by mass) and 100 mL of the tin stripping solution additive prepared in example 2 were added to 100 mL of pure water, and finally the volume was made up to 1 L with pure water.

[0063] The tin stripping solution prepared in the above application example 4 was used to treat the plating assistant board at 25℃, the tin layer of the plating assistant board was about 6 microns, the copper layer was about 52 microns, and the tin was stripped for 50 seconds by immersion and swing.

[0064] The tin stripping rate was measured by the method described above

[0065] The tin stripping rate was 8 microns / minute at 15℃, 20℃, 25℃ and 30℃.

[0066] The copper removal rate is: 0.3 microns / min at 30°C; 0.08 microns / min at 25°C; 0.06 microns / min at 20°C; and 0.02 microns / min at 15°C.

[0067] The concentration of hydrogen peroxide in the sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 4 does not change after the water is left to stand for 10 days.

[0068] The nitrogen content test: ① Tin removal water additive: 10.07 g / L; ② Tin removal tank working solution: 0.44 g / L.

[0069] Application Example 5

[0070] Preparation of sulfuric acid-hydrogen peroxide system tin removal water: 450 mL of sulfuric acid (50% by mass), 3 mL of hydrogen peroxide (50% by mass), and 50 mL of the tin removal water additive prepared in Example 2 were added to 100 mL of pure water under continuous stirring, and then the volume was made up to 1 L with pure water.

[0071] The sulfuric acid-hydrogen peroxide system tin removal water prepared in the above-described Application Example 5 was used to treat a strike plate at 25°C, the strike plate having a tin layer of about 6 microns and a copper layer of about 52 microns, and the strike plate was immersed and oscillated for 80 seconds to remove the tin.

[0072] The tin removal rate was measured by the method described above.

[0073] The tin removal rate is: 5 microns / min at 20°C, 25°C, and 30°C.

[0074] The copper removal rate is: 0.2 microns / min at 30°C; 0.06 microns / min at 25°C; and 0.03 microns / min at 20°C.

[0075] The concentration of hydrogen peroxide in the sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 5 does not change after the water is left to stand for 10 days.

[0076] The nitrogen content test: ① Tin removal water additive: 10.07 g / L; ② Tin removal tank working solution: 0.44 g / L.

[0077] Application Example 6

[0078] Preparation of sulfuric acid-hydrogen peroxide system tin removal water: 550 mL of sulfuric acid (50% by mass), 7 mL of hydrogen peroxide (50% by mass), and 150 mL of the tin removal water additive prepared in Example 2 were added to 100 mL of pure water under continuous stirring, and then the volume was made up to 1 L with pure water.

[0079] The tin stripping solution prepared in the above application example 6 was used to treat the plating assistant board at 25℃, the tin layer of the plating assistant board was about 6 microns, the copper layer was about 52 microns, and the tin was stripped for 30 seconds by soaking and swinging.

[0080] The tin stripping rate was measured by the above method

[0081] The tin stripping rate was 12 microns / minute at 20℃, 25℃ and 30℃.

[0082] The copper stripping rate was 0.35 microns / minute at 30℃, 0.09 microns / minute at 25℃ and 0.04 microns / minute at 20℃.

[0083] The concentration of hydrogen peroxide in the tin stripping solution prepared in application example 6 did not change after being placed for 10 days.

[0084] Nitrogen content test: ① Tin stripping solution additive: 10.07 g / L; ② Tin stripping tank working solution: 1.02 g / L.

[0085] Example 3

[0086] Preparation of tin stripping solution additive: 35 g of 8-hydroxyquinoline, 60 mL of phenol sulfonic acid, 10 mL of ethanolamine, 20 g of urea and 150 mL of sulfuric acid (50% by mass) were added to 500 mL of pure water under continuous stirring, and finally the volume was made up to 1 L with pure water to obtain the tin stripping solution additive.

[0087] Application example 7

[0088] Preparation of sulfuric acid-hydrogen peroxide system tin stripping solution: 500 mL of sulfuric acid (50% by mass), 5 mL of hydrogen peroxide (50% by mass) and 100 mL of the tin stripping solution additive prepared in example 3 were added to 100 mL of pure water under continuous stirring, and finally the volume was made up to 1 L with pure water.

[0089] The tin stripping solution prepared in the above application example 7 was used to treat the plating assistant board at 25℃, the tin layer of the plating assistant board was about 6 microns, the copper layer was about 52 microns, and the tin was stripped for 50 seconds by soaking and swinging.

[0090] The tin stripping rate was measured by the above method

[0091] The tin stripping rate was 8 microns / minute at 15℃, 20℃, 25℃ and 30℃.

[0092] The copper removal rate is: 0.3 microns / min at 30°C; 0.08 microns / min at 25°C; 0.06 microns / min at 20°C; and 0.02 microns / min at 15°C.

[0093] The concentration of hydrogen peroxide in the sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 8 does not change after the water is left to stand for 10 days.

[0094] Nitrogen content test: ① Tin removal water additive: 9.44 g / L; ② Tin removal tank working solution: 0.79 g / L.

[0095] Application Example 8

[0096] Preparation of sulfuric acid-hydrogen peroxide system tin removal water: Under continuous stirring, 450 mL of sulfuric acid (50% by mass), 3 mL of hydrogen peroxide (50% by mass), and 50 mL of the tin removal water additive prepared in Example 3 were added to 100 mL of pure water, and then the volume was made up to 1 L with pure water.

[0097] The sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 8 above was used to treat a strike plate at 25°C, the strike plate having a tin layer of about 6 microns and a copper layer of about 52 microns, and the strike plate was immersed and oscillated for 80 seconds to remove the tin.

[0098] The tin removal rate was measured by the method described above.

[0099] The tin removal rate was 5 microns / min at 20°C, 25°C, and 30°C.

[0100] The copper removal rate is: 0.2 microns / min at 30°C; 0.06 microns / min at 25°C; and 0.03 microns / min at 20°C.

[0101] The concentration of hydrogen peroxide in the sulfuric acid-hydrogen peroxide system tin removal water prepared in Application Example 8 does not change after the water is left to stand for 10 days.

[0102] Nitrogen content test: ① Tin removal water additive: 9.44 g / L; ② Tin removal tank working solution: 0.41 g / L.

[0103] Application Example 9

[0104] Preparation of sulfuric acid-hydrogen peroxide system tin removal water: Under continuous stirring, 550 mL of sulfuric acid (50% by mass), 7 mL of hydrogen peroxide (50% by mass), and 150 mL of the tin removal water additive prepared in Example 3 were added to 100 mL of pure water, and then the volume was made up to 1 L with pure water.

[0105] The tin stripping solution prepared in the above application example 9 was used to treat the plating assistant panel at 25℃, the tin layer of the plating assistant panel was about 6 microns, the copper layer was about 52 microns, and the tin was stripped for 30 seconds by soaking and swinging.

[0106] The tin stripping rate was measured by the method described above

[0107] The tin stripping rate was 12 microns / minute at 20℃, 25℃ and 30℃.

[0108] The copper stripping rate was 0.35 microns / minute at 30℃, 0.09 microns / minute at 25℃ and 0.04 microns / minute at 20℃.

[0109] The concentration of hydrogen peroxide in the tin stripping solution prepared in the above application example 9 did not change after the solution was placed for 10 days.

[0110] The nitrogen content test: ① Tin stripping solution additive: 9.44 g / L; ② Tin stripping tank working solution: 0.95 g / L.

[0111] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, and all shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of a desmear water additive, characterized in that, The method comprises the following steps: The tin stripping water additive is prepared by adding 8-hydroxyquinoline, phenol sulfonic acid, ethanolamine, urea and sulfuric acid into water under continuous stirring, and then adding water to constant volume. The mass of 8-hydroxyquinoline added in each liter of the tin stripping water additive is 25-35 g; the volume of phenol sulfonic acid added in each liter of the tin stripping water additive is 40-60 mL; the volume of ethanolamine added in each liter of the tin stripping water additive is 10-30 mL; the mass of urea added in each liter of the tin stripping water additive is 5-20 g; and the volume of sulfuric acid added in each liter of the tin stripping water additive is 100-150 mL.

2. The tin stripping water additive prepared by the preparation method of claim 1.

3. The method of using the stiich remover additive of claim 2, wherein, In the tin stripping process of the sulfuric acid / hydrogen peroxide system, sulfuric acid, hydrogen peroxide and the tin stripping water additive are added into the tin stripping water, the operation temperature is controlled below 30 DEG C, and the addition amount of the tin stripping water additive satisfies that 50-150 mL of the tin stripping water additive is added in each liter of the tin stripping water.

4. The method of claim 3, wherein the stannum removal water additive is used in an amount of 0.1 to 10 ppm. 450-550 mL of sulfuric acid is added in each liter of the tin stripping water. ​ 5. The method of claim 3, wherein the stannum removal water additive is used in an amount of 0.1 to 10 ppm. 3-7 mL of hydrogen peroxide is added in each liter of the tin stripping water. ​

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