Acidic degreaser for VCP wire in PCB manufacturing process and use method of acidic degreaser

Abstract

The invention relates to the technical field of electroplating pretreatment, in particular to an acidic degreaser for a VCP wire in a PCB manufacturing process and a use method of the acidic degreaser. The acidic degreasing agent is prepared from the following raw materials: 1-100 g / L of a nonionic surfactant, 0.5-15 g / L of a chelating agent, 1-30 g / L of silicate, 2-100 g / L of composite acid and water as a solvent, and the foam height of the acidic degreasing agent is less than 10mm when the acidic degreasing agent is sprayed to remove oil. The invention provides a low-foam acidic degreaser, and aims to ensure smooth proceeding of a degreasing and cleaning process and effectively maintain the integrity and reliability of pattern electroplating at the same time. By adopting a low-foam formula, foam is remarkably reduced while efficient cleaning is performed, interference to the electroplating process is avoided, and therefore the production quality and efficiency of VCP wire electroplating in the PCB manufacturing process are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of electroplating pretreatment, and in particular to an acidic degreasing agent for a VCP line in a PCB process and a use method thereof. Background Art

[0002] The electroplating pretreatment of the vertical continuous plating line (VCP line) in the PCB process is a key process that must be passed before electroplating. It can ensure that the surface and holes of the PCB plated parts are clean and that there are no plating-blocking substances that affect the electroplating quality of the plated parts. Limited by the characteristics and operating requirements of the VCP line, the cleaning of the VCP line needs to comprehensively consider the risk of plating solution contamination, board complexity, electroplating efficiency and other comprehensive factors; currently, the VCP line usually uses a spraying method to clean the board surface instead of an immersion method to achieve cleaning. Therefore, if a conventional degreaser is used, it is easy to produce a large amount of foam overflowing the production line, hindering normal electroplating. Among the current technical means, most VCP lines use sulfuric acid aqueous solution (concentration of about 5-15%) for simple electroplating pretreatment cleaning. After actual electroplating, there are still defects such as fingerprints and rough plating caused by the attachment of debris. The current degreasers are mostly multi-foam degreasers, and the generation of a large amount of foam will hinder the electroplating process. Therefore, it is particularly important to develop a low-foam degreaser specifically for VCP line cleaning.

[0003] Chinese patent application CN112877143A discloses a method for preparing an acidic degreasing agent for PCB circuit boards, wherein cycloalkanes are added to the degreasing agent, and the oil stains on the surface of the PCB circuit board are dissolved by the cycloalkanes, thereby improving the effect of removing oil from the PCB circuit board, and organic amine esters are added to dissolve the metal oxides on the surface of the PCB circuit board, thereby further improving the degreasing effect of the PCB circuit board. Chinese patent CN114774937B discloses an environmentally friendly inorganic acidic degreasing agent and degreasing method for circuit board electroplating, wherein the acidic degreasing agent is composed of effective ingredients such as inorganic acid, corrosion inhibitor, wetting agent, stabilizer and promoter, has a fast and excellent degreasing effect, does not corrode the metal on the surface of the circuit board, and has good stability at high temperatures. However, none of these prior arts solve the technical problem that the degreasing agent has too high foam during spraying treatment, which affects normal electroplating, and the temperature is high during degreasing treatment, and the energy consumption is high.

[0004] Under such circumstances, there is an urgent need to provide a low-foam degreasing agent with high cleaning efficiency that can ensure normal electroplating. Summary of the invention

[0005] In view of the shortcomings of existing PCB processes and electroplating technologies, the present invention provides a low-foaming acidic degreasing agent, which aims to ensure the smooth progress of the degreasing and cleaning process, while effectively maintaining the integrity and reliability of the pattern electroplating. By adopting a low-foaming formula, the generation of foam is significantly reduced while efficiently cleaning, avoiding interference with the electroplating process, thereby further improving the production quality and efficiency of VCP line electroplating in the PCB process.

[0006] The first aspect of the present invention provides an acidic degreasing agent for a VCP line of a PCB process. The raw materials for preparing the acidic degreasing agent include: 1-100 g / L of a nonionic surfactant, 0.5-15 g / L of a chelating agent, 1-30 g / L of a silicate, 2-100 g / L of a composite acid, and the solvent is water.

[0007] In some preferred embodiments, the foam height of the acidic degreasing agent during spray degreasing is less than 10 mm.

[0008] In some preferred embodiments, the raw materials for preparing the acidic deoiling agent include: 5-50 g / L nonionic surfactant, 1-10 g / L chelating agent, 2-20 g / L silicate, 6-85 g / L composite acid, and the solvent is water.

[0009] In the process of PCB (printed circuit board) electroplating, full board electroplating and pattern electroplating are two key steps. Especially in the process of pattern electroplating, it is very important to choose an appropriate degreaser. If an alkaline degreaser is used, it may corrode the dry film layer covering the surface of the PCB plated part, which will cause poor penetration, that is, the plating solution may penetrate the area covered by the dry film, resulting in the part that should not be electroplated being plated with metal, affecting the quality and performance of the product. Therefore, when using the VCP line for pattern electroplating, in order to ensure the accuracy of the electroplating process and the quality of the PCB parts, an acidic degreaser must be used. Acidic degreasers are relatively mild and can effectively remove oil stains while avoiding damage to the dry film covering layer, thereby ensuring the accuracy and integrity of the electroplating pattern. This choice not only meets the technical requirements of PCB electroplating, but is also an important measure to ensure product quality and production efficiency.

[0010] The nonionic surfactants include nonylphenol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymers, ethylene oxide propylene oxide copolymers, fatty alcohol polyoxyethylene ether, fatty alcohol ethoxylates, alkylphenol polyoxyethylene ether, alkanolamides, polyol fatty acid esters and the like.

[0011] In some preferred embodiments, the nonionic surfactant includes nonylphenol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer, ethylene oxide propylene oxide copolymer, fatty alcohol polyoxyethylene ether and fatty alcohol ethoxylate.

[0012] More preferably, the mass ratio of the nonylphenol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer, ethylene oxide propylene oxide copolymer, fatty alcohol polyoxyethylene ether, and fatty alcohol ethoxylate is (1-10): (1-10): (1-10): (1-10): (1-10).

[0013] The chelating agent can be exemplified by disodium EDTA, sodium tripolyphosphate, sodium hexametaphosphate, nitrilotriacetic acid, benzohydroxamic acid, salicylic hydroxamic acid, etc.; preferably, disodium EDTA.

[0014] The silicates can be listed as sodium metasilicate, sodium silicate, potassium metasilicate, potassium silicate, magnesium iron silicate, aluminum silicate, etc.; preferably, the combination of sodium metasilicate and sodium silicate.

[0015] In some preferred embodiments, the amount of silicates added is 1-20 g / L.

[0016] The composite acid can be at least two of sulfuric acid, citric acid, benzoic acid, phosphoric acid, hydrochloric acid, nitric acid, acetic acid, aminosulfonic acid, and oxalic acid; preferably, it is a combination of sulfuric acid, citric acid and benzoic acid.

[0017] In some preferred embodiments, the raw materials for preparing the acidic degreasing agent include: 1-10 g / L of nonylphenol polyoxyethylene ether, 1-10 g / L of fatty alcohol-alkylene oxide copolymer, 1-10 g / L of ethylene oxide propylene oxide copolymer, 1-10 g / L of fatty alcohol polyoxyethylene ether, 1-10 g / L of fatty alcohol ethoxylate, 1-10 g / L of disodium EDTA, 1-10 g / L of sodium metasilicate, 1-10 g / L of sodium silicate, 0.05-1 g / L of benzoic acid, 1-30 g / L of citric acid, 5-50 g / L of sulfuric acid, and the solvent is water.

[0018] More preferably, the mass ratio of the nonylphenol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer, ethylene oxide propylene oxide copolymer, fatty alcohol polyoxyethylene ether, and fatty alcohol ethoxylate is (5-8): (5-8): (3-6): (5-8): (3-8).

[0019] In some preferred embodiments, the molecular weight of the fatty alcohol-alkylene oxide copolymer is 500-4000; the molecular weight of the ethylene oxide-propylene oxide copolymer is 1000-2000; and the molecular weight of the fatty alcohol polyoxyethylene ether is 1000-2000.

[0020] More preferably, the molecular weight of the fatty alcohol-alkylene oxide copolymer is 500-1000.

[0021] More preferably, the molecular weight of the ethylene oxide propylene oxide copolymer is 1000-1500.

[0022] More preferably, the molecular weight of the fatty alcohol polyoxyethylene ether is 2000.

[0023] In some preferred embodiments, the mass ratio of the sodium metasilicate to sodium silicate is 1:(0.5-2); more preferably 1:1.

[0024] In some preferred embodiments, the mass ratio of sulfuric acid, citric acid and benzoic acid is (20-35):(3-15):(0.05-0.2).

[0025] The second aspect of the present invention provides a method for using the acidic degreasing agent as described above, using the acidic degreasing agent to degrease the VCP line of the PCB process; specifically, during the degreasing treatment, the amount of the acidic degreasing agent added to the aqueous solution is 3-20wt%, and the degreasing treatment temperature is 10-40°C.

[0026] In some preferred embodiments, the volume addition amount of the acidic degreasing agent in the aqueous solution is 5-10%, and the degreasing treatment temperature is 20-30°C.

[0027] Beneficial effects:

[0028] The present invention provides a PCB process VCP line acid degreasing agent and a use method thereof, which has the following advantages:

[0029] (1) The present invention preferably uses a specific non-ionic surfactant compound, and the resulting acidic degreasing agent has a significant low-foaming performance. The foam height does not exceed 10 mm during the spraying process, which effectively avoids the foam overflowing the production line and ensures the smooth progress of the electroplating process. This feature enables the degreasing agent to perfectly adapt to the production requirements of the VCP line.

[0030] (2) The present invention combines disodium EDTA with a nonionic surfactant. After the acidic degreasing agent is treated, no oil film remains on the surface and inside the holes of the PCB plated parts, which effectively solves the problem of rough plating layer caused by fingerprints, debris adhesion, etc., ensures the smoothness and adhesion of the electroplating layer, and improves the overall quality of the PCB parts.

[0031] (3) The present invention selects sulfuric acid, citric acid and benzoic acid for compounding, and the obtained acidic degreasing agent has efficient cleaning and degreasing effects, and is specially designed for the vertical continuous electroplating line (VCP line) in the PCB process. It adopts a spraying method to efficiently clean the board surface and the inside of the hole, ensuring that no plating-blocking substances remain, thereby significantly improving the quality and uniformity of the electroplating layer.

[0032] (4) The acidic degreasing agent of the present invention has mild chemical properties, which avoids the risk of corrosion of the dry film layer covering the surface of the PCB plated parts. The obtained acidic degreasing agent is particularly suitable for the needs of VCP line production of graphic electroplating.

[0033] (5) The acidic degreasing agent of the present invention can be applied to the PCB process to significantly improve the electroplating yield rate and reduce electroplating defects caused by incomplete cleaning or foam overflow. At the same time, its low foaming performance and high-efficiency cleaning ability also improve production efficiency and reduce production costs, and has extremely high practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 . Surface image of the plated part after electroplating in Example 1;

[0035] Figure 2 . Surface diagram of the plated part after electroplating in Example 2;

[0036] Figure 3 . Surface image of the plated part after electroplating in Example 3;

[0037] Figure 4 . Surface image of the plated part after electroplating in Example 4;

[0038] Figure 5 . Surface diagram of the plated part after electroplating in Comparative Example 1;

[0039] Figure 6 .Surface image of the plated part after electroplating in comparative example 2. DETAILED DESCRIPTION

[0040] The source information of some raw materials involved in the embodiments of the present invention is as follows.

[0041] Nonylphenol polyoxyethylene ether: from McLean, brand number N823211.

[0042] Fatty alcohol-alkylene oxide copolymer: Mn (average molecular weight) is 638, sourced from McLean, brand number A794354.

[0043] Ethylene oxide and propylene oxide copolymer: Mn (average molecular weight) is 1100, sourced from McLean, brand number P875724.

[0044] Fatty alcohol polyoxyethylene ether: AEO-9, from McLean, brand number A921929.

[0045] Alkylphenol polyoxyethylene ether: OP-10, from Aladdin, brand number O304931.

[0046] Example

[0047] Examples 1 to 4 and Comparative Examples 1 to 2

[0048] Examples 1 to 4 and Comparative Examples 1 to 2 provide an acidic degreasing agent for a VCP line of a PCB manufacturing process and an application method thereof. The components of the acidic degreasing agent are shown in Table 1.

[0049] Table 1

[0050]

[0051]

[0052] The preparation steps of the acidic degreasing agent include: mixing the raw materials uniformly to obtain the acidic degreasing agent.

[0053] The acidic degreasing agent provided in Example 1 was used after being prepared into a 5% (v / v) aqueous solution during degreasing treatment, and the temperature of the degreasing treatment was 25°C.

[0054] The acidic degreasing agent provided in Example 2 was used after being prepared into a 4% (v / v) aqueous solution during degreasing treatment, and the degreasing treatment temperature was 25°C.

[0055] The acidic degreasing agent provided in Example 3 was used after being prepared into a 7% (v / v) aqueous solution during degreasing treatment, and the degreasing treatment temperature was 25°C.

[0056] The acidic degreasing agent provided in Example 4 was prepared as a 10% (v / v) aqueous solution for use in the degreasing treatment, and the degreasing treatment temperature was 25°C.

[0057] The acidic degreasing agent provided in Comparative Example 1 was used after being prepared into a 10% (v / v) aqueous solution during degreasing treatment, and the degreasing treatment temperature was 25°C.

[0058] The acidic degreasing agent provided in Comparative Example 2 was used after being prepared into a 10% (v / v) aqueous solution during degreasing treatment, and the degreasing treatment temperature was 25°C.

[0059] Performance Testing

[0060] The acidic degreasing agent provided in Examples 1 to 4 and Comparative Examples 1 to 2 was subjected to a degreasing test. The test method was as follows: the surface of the PCB plated part was coated with triglyceride to form an oil film with a thickness of 1 μm, and then the PCB plated part was sprayed with the degreasing agent prepared in Examples 1 to 4 and Comparative Examples 1 to 2 (which had been diluted into an aqueous solution according to the set application concentration) for degreasing. After the spraying treatment, the PCB plated part was taken out and cleaned, and then washed with water and acid in turn, and then a VCP line electroplating test was simulated. The process and parameter settings during the test are shown in Table 2, and the final test results are shown in Tables 3 and Figure 1-6 .

[0061] Table 2

[0062]

[0063]

[0064] Note: The plating solution formula during the electroplating process is: brightener 1mL / L, copper sulfate pentahydrate 75g / L, sulfuric acid 220g / L, Cl - (derived from hydrochloric acid) 60ppm, the solvent is water.

[0065] The brightener is the SCC-200U electroplating brightener product of Guangdong Shuocheng Technology Co., Ltd.

[0066] Table 3

[0067]

[0068] As shown in the test results in Table 3, the foam height of the acidic degreasers of Examples 1-4 in the spray process does not exceed 10 mm, and they are suitable for spray degreasing during VCP electroplating pretreatment. After degreasing, there is no oil film residue on the sample surface, and there is no problem of plated parts blocking plating. However, the acidic degreaser of Comparative Example 1 produces 75 mm thick foam, which will cause foam overflow and cannot be used in VCP electroplating process; the foam height of the acidic degreaser of Comparative Example 2 reaches 50 mm, and there is also the problem of excessive foam and cannot be used in VCP electroplating process. In addition, there is a slight oil film residue after degreasing in Comparative Example 2, causing a small area blocking plating problem. It can be seen that only by using the acidic degreaser of the preferred formula of the present invention can the technical effects of low foam height, good degreasing effect and no blocking plating be achieved.

Claims

1. A PCB process VCP line acid degreasing agent, characterized in that: The raw materials for preparing the acidic degreasing agent include: 1-100 g / L of nonionic surfactant, 0.5-15 g / L of chelating agent, 1-30 g / L of silicate, 2-100 g / L of composite acid, and the solvent is water; The foam height of the acidic degreasing agent during spraying and degreasing is less than 10 mm.

2. The PCB process VCP line acid degreasing agent according to claim 1, characterized in that: The nonionic surfactant includes nonylphenol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer, ethylene oxide propylene oxide copolymer, fatty alcohol polyoxyethylene ether and fatty alcohol ethoxylate; Preferably, the mass ratio of the nonylphenol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer, ethylene oxide propylene oxide copolymer, fatty alcohol polyoxyethylene ether, and fatty alcohol ethoxylate is (1-10): (1-10): (1-10): (1-10): (1-10).

3. The acidic degreasing agent for PCB process VCP line according to claim 2, characterized in that: The mass ratio of the nonylphenol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer, ethylene oxide propylene oxide copolymer, fatty alcohol polyoxyethylene ether and fatty alcohol ethoxylate is (5-8): (5-8): (3-6): (5-8): (3-8).

4. The PCB process VCP line acidic degreasing agent according to claim 2, characterized in that: The average molecular weight of the fatty alcohol-alkylene oxide copolymer is 500-4000; the average molecular weight of the ethylene oxide-propylene oxide copolymer is 1000-2000; and the average molecular weight of the fatty alcohol polyoxyethylene ether is 1000-2000.

5. The acidic degreasing agent for PCB process VCP line according to claim 1, characterized in that: The chelating agent includes disodium EDTA, and the added amount of the chelating agent is 1-10 g / L.

6. The acidic degreasing agent for PCB process VCP line according to claim 1, characterized in that: The composite acid includes at least two of sulfuric acid, citric acid, benzoic acid, phosphoric acid, hydrochloric acid, nitric acid, acetic acid, aminosulfonic acid, and oxalic acid.

7. The acidic degreasing agent for PCB process VCP line according to claim 6, characterized in that: The composite acid includes sulfuric acid, citric acid and benzoic acid; Preferably, the mass ratio of sulfuric acid, citric acid and benzoic acid is (5-50):(1-30):(0.05-1).

8. The acidic degreasing agent for PCB process VCP line according to claim 1, characterized in that: The silicates include sodium metasilicate and sodium silicate, and the addition amount of the silicates is 1-20 g / L.

9. The acidic degreasing agent for PCB process VCP line according to claim 8, characterized in that: The mass ratio of the sodium metasilicate to sodium silicate is 1:(0.5-2).

10. A method for using the acidic degreasing agent according to any one of claims 1 to 9, characterized in that: The VCP line of the PCB process is degreased using an acidic degreaser. During the degreasing treatment, the volume addition amount of the acidic degreaser in the aqueous solution is 3-20%, and the degreasing treatment temperature is 10-40°C.

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