Acidic degreaser for horizontal plating line in PCB (Printed Circuit Board) 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 horizontal electroplating line in a PCB (Printed Circuit Board) manufacturing process and a use method. The acidic degreaser is prepared from the following raw materials: 1-70 g / L of a surfactant, 1-12 g / L of a chelating agent, 1-50 g / L of a stabilizer, 2-80 g / L of inorganic acid and water as a solvent. The surface active agent comprises a non-ionic surface active agent or a cationic surface active agent; and the foam height of the acidic degreasing agent is below 8mm when the acidic degreasing agent is sprayed to remove oil. The acidic degreasing agent is preferably compounded with a specific nonionic surfactant, oil stains can be efficiently removed, no oil film is left on the surface of a sample after degreasing, the surface cleanliness of a workpiece before electroplating is ensured, and the electroplating quality is improved. Meanwhile, the specific inorganic acid and the stabilizer are preferably selected, oil stains can be thoroughly removed, the plating resistance problem caused by oil film residues is avoided, and therefore it is guaranteed that the electroplating liquid can evenly cover the surface of a workpiece, and plating resistance is avoided.

Description

Technical Field

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

[0002] The pre-treatment of the horizontal electroplating line in the PCB (printed circuit board) process is a process that must be passed before electroplating. This step can ensure that the surface and holes of the PCB plated material are clean and that there are no plating-blocking substances that affect the electroplating quality of the plated parts. The horizontal electroplating line usually uses a spray + immersion method to clean the board surface, and the processing time is only 30-45s. Compared with conventional gantry electroplating (3-5min) and VCP electroplating (1-3min), it has the outstanding advantage of short processing time. However, in actual operation, if conventional degreasing agents are used, it is easy to produce unclean cleaning and a large amount of foam overflowing the production line, hindering normal electroplating. At the same time, this method has high requirements for processing. If it is not handled well, problems such as fingerprints, debris adhesion, copper particles, etc. are likely to occur after actual electroplating, which will have negative problems on the electroplating layer.

[0003] Chinese patent CN100419126C discloses a biological deoiling agent used for pre-treatment of oil removal and degreasing in the metal processing industry and a method for treating oil stains on metal surfaces. The technology uses a biological deoiling agent with the dual functions of removing oil and decomposing oil stains, including 0.1 to 60 weight % of a surfactant, 0.1 to 30 weight % of an oleophilic microorganism, and the remainder is water, combining the two processes of removing oil stains on the metal surface and decomposing oil stains into one process for treatment.

[0004] Chinese patent application CN118880345A discloses an acidic metal degreasing agent and a degreasing process, wherein the corrosion inhibitor is preferably composed of hydroxyethylidene diphosphonic acid and methyl imidazoline in a mass ratio of (0.5-3): (0.2-1). Through the mutual cooperation and joint action of the components in the degreasing agent and strict control of the ratio of the components, the degreasing performance of the degreasing agent at low temperatures is improved.

[0005] Most of the current degreasing agents are multi-foaming degreasing agents, which cannot effectively solve the above problems and reduce the foam height of the degreasing agent during treatment, and thus cannot meet the process requirements of spraying + immersion of horizontal electroplating lines. In this context, it is particularly important to develop a low-foaming and high-efficiency degreasing agent. Summary of the invention

[0006] In view of the limitations of existing electroplating processes and technical capabilities, the present invention innovatively launches a low-foaming, high-efficiency acidic degreaser, which is particularly suitable for the pre-treatment production line of horizontal electroplating lines, aiming to ensure the smooth progress of the degreasing and cleaning process, while strictly ensuring the integrity and high reliability of the plated parts.

[0007] The first aspect of the present invention provides an acidic degreasing agent for a horizontal electroplating line of a PCB process. The raw materials for preparing the acidic degreasing agent include: 1-70 g / L of a surfactant, 1-12 g / L of a chelating agent, 1-50 g / L of a stabilizer, 2-80 g / L of an inorganic acid, and the solvent is water.

[0008] In some preferred embodiments, the foam height of the acidic degreasing agent during spray degreasing is less than 8 mm.

[0009] More preferably, the raw materials for preparing the acidic deoiling agent include: 10-50 g / L of surfactant, 2-8 g / L of chelating agent, 3-30 g / L of stabilizer, 10-60 g / L of inorganic acid, and the solvent is water.

[0010] Preferably, the surfactant comprises a nonionic surfactant or a cationic surfactant. More preferably, the surfactant comprises a nonionic surfactant.

[0011] Preferably, the nonionic surfactant includes one or more combinations of isomeric fatty alcohol polyoxyethylene ethers, fatty alcohol ethoxylates, ethylene oxide propylene oxide copolymers, and fatty alcohol-alkylene oxide copolymers.

[0012] More preferably, the nonionic surfactant includes isomeric fatty alcohol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer and ethylene oxide propylene oxide copolymer, and the mass ratio is (1-20): (1-10): (1-10); more preferably (3-10): (3-5): (4-7).

[0013] Preferably, the isomeric fatty alcohol polyoxyethylene ether includes isomeric C10 alcohol polyoxyethylene ether, and the molecular weight of the isomeric C10 alcohol polyoxyethylene ether is 200-1000.

[0014] Preferably, the isomeric fatty alcohol polyoxyethylene ether also includes isomeric fatty alcohol polyoxyethylene ether with a carbon atom number of 10-15 and an epoxy addition number of 30-50; as an example, the product MULTISO 13 / 40 produced by Sasol can be cited (wherein 13 is the carbon atom number and 40 is the epoxy addition number).

[0015] Preferably, the average molecular weight of the fatty alcohol-alkylene oxide copolymer is 500-3000; more preferably 600-700.

[0016] Preferably, the average molecular weight of the ethylene oxide propylene oxide copolymer is 1000-2500; more preferably 1000-1500; most preferably 1100.

[0017] The chelating agent can be exemplified by disodium EDTA, sodium tripolyphosphate, sodium hexametaphosphate, nitrilotriacetic acid, benzohydroxamic acid, salicylic hydroxamic acid, etc.; preferably, disodium EDTA is included.

[0018] More preferably, the amount of disodium EDTA added to the acidic degreasing agent is 1-10 g / L.

[0019] Preferably, the stabilizer includes at least two of sodium citrate, sodium silicate, sodium metasilicate, acrylamide, and soluble cellulose.

[0020] More preferably, the stabilizer comprises sodium citrate and sodium silicate in a mass ratio of (2-7):1.

[0021] Preferably, the amount of sodium citrate added to the acidic degreasing agent is 1-30 g / L.

[0022] Preferably, the amount of sodium silicate added to the acidic degreasing agent is 1-10 g / L.

[0023] In some embodiments, the inorganic acid can be exemplified by sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like.

[0024] Preferably, the inorganic acid includes sulfuric acid, and the amount of sulfuric acid added to the acidic degreasing agent is 20-60 g / L.

[0025] The present invention has no special limitation on the preparation method of the acidic degreasing agent, and the conventional preparation method in the art can be adopted; for example, the raw materials are mixed to obtain the acidic degreasing agent product.

[0026] The horizontal electroplating line has extremely high requirements for the cleanliness of the workpiece surface, and any oil film residue may lead to poor electroplating. Traditional degreasing agents are usually unable to completely remove the oil stains on the workpiece surface. The acidic degreasing agent of the present invention is preferably compounded with a specific non-ionic surfactant. Through the effects of isomeric fatty alcohol polyoxyethylene ethers, fatty alcohol-alkylene oxide copolymers and ethylene oxide propylene oxide copolymers, it can efficiently remove oil stains, and there is no oil film residue on the sample surface after degreasing, which ensures the cleanliness of the workpiece surface before electroplating and improves the electroplating quality. At the same time, specific inorganic acids and stabilizers are preferably selected, especially the inorganic acid is sulfuric acid, and the stabilizers are sodium citrate and sodium silicate, which can completely remove oil stains and avoid the plating resistance problem caused by the oil film residue, thereby ensuring that the electroplating solution can evenly cover the workpiece surface and improve the uniformity and consistency of electroplating.

[0027] A second aspect of the present invention provides a method for using an acidic degreasing agent for a horizontal electroplating line in a PCB process, wherein the acidic degreasing agent is used to degrease the horizontal electroplating line in the PCB process.

[0028] In some preferred embodiments, the volume amount of the acidic deoiling agent added in the aqueous solution during deoiling treatment is 1-20%; more preferably, the volume amount of the acidic deoiling agent added in the aqueous solution is 2-16%; further preferably, it is 2-10%.

[0029] In some preferred embodiments, the oil removal treatment time is 2-60 s, more preferably 5-30 s.

[0030] In some preferred embodiments, the temperature of the deoiling treatment is 40-60°C; more preferably 50°C.

[0031] In the spray process of the horizontal electroplating line, the generation of foam is an unavoidable and difficult to control problem. Excessive foam will not only overflow the tank, causing environmental pollution and production interruption, but may also affect the uniformity of the electroplating solution and the quality of electroplating. However, the acidic degreaser with the preferred formula of the present invention has an extremely low foam height in the spray process, not exceeding 8mm, which effectively avoids the various adverse effects of foam on the electroplating process and parts, thereby significantly reducing the processing difficulty of the horizontal electroplating line. What is even more rare is that the degreasing treatment time of the present invention is extremely short, only 2-60s, which can efficiently and thoroughly remove oil impurities to match the electroplating requirements of the horizontal electroplating line.

[0032] Beneficial effects:

[0033] The present invention provides an acidic degreasing agent for a horizontal electroplating line of a PCB process and a method for using the same, which has the following advantages:

[0034] (1) Significantly reduce the foam problem during processing: In the spray process of the horizontal electroplating line, the generation of foam is an unavoidable and difficult to control problem. Excessive foam will not only overflow the tank, causing environmental pollution and production interruption, but may also affect the uniformity of the electroplating solution and the quality of electroplating. However, the acidic degreasing agent of the preferred formula of the present invention has an extremely low foam height in the spray process, not exceeding 8mm, which effectively avoids various adverse effects of foam on the electroplating process and parts, thereby significantly reducing the processing difficulty of the horizontal electroplating line.

[0035] (2) Improve the efficiency and effect of oil removal: The horizontal electroplating line has extremely high requirements for the cleanliness of the workpiece surface. Any oil film residue may lead to poor electroplating. Traditional degreasing agents are usually unable to completely remove the oil stains on the workpiece surface. The acidic degreasing agent of the present invention is preferably compounded with a specific non-ionic surfactant, which can efficiently remove oil stains, and there is no oil film residue on the sample surface after degreasing, which ensures the cleanliness of the workpiece surface before electroplating and improves the electroplating quality.

[0036] (3) Reduce plating resistance and improve electroplating uniformity: Oil film residue is one of the main causes of plating resistance during electroplating. The acidic degreasing agent of the present invention is preferably a specific inorganic acid and a stabilizer, which can completely remove oil stains and avoid plating resistance caused by oil film residue, thereby ensuring that the electroplating solution can evenly cover the surface of the workpiece and improving the uniformity and consistency of electroplating.

[0037] (4) Optimizing the production process and improving production efficiency: The acidic degreasing agent of the preferred formula of the present invention has low foam height and good degreasing effect in the spraying process, so it can significantly reduce the processing time and number of repeated treatments of the degreasing process, thereby optimizing the production process and improving production efficiency. This is of great significance for the horizontal electroplating line that pursues efficient and high-quality production.

[0038] (5) Enhanced production stability and sustainability: Traditional degreasing agents tend to generate a large amount of foam and waste liquid during use, causing environmental pollution and affecting production stability. The acidic degreasing agent of the preferred formula of the present invention not only has low foam height, but also generates less waste liquid during use, which is easy to handle and meets environmental protection requirements, and can promote the electroplating process to develop in a more green, environmentally friendly and sustainable direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 . Surface image of the plated part after electroplating in Example 1;

[0040] Figure 2 . Surface diagram of the plated part after electroplating in Example 2;

[0041] Figure 3 . Surface image of the plated part after electroplating in Example 3;

[0042] Figure 4 . Surface image of the plated part after electroplating in Example 4;

[0043] Figure 5 . Surface diagram of the plated part after electroplating in Comparative Example 1;

[0044] Figure 6 .Surface image of the plated part after electroplating in comparative example 2. DETAILED DESCRIPTION

[0045] Based on the electroplating processing requirements of the horizontal electroplating line, the present invention provides an acidic degreasing agent for the horizontal electroplating line of a PCB process and a method of using the same. The raw materials for preparing the acidic degreasing agent include: a surfactant 1-70 g / L, a chelating agent 1-12 g / L, a stabilizer 1-50 g / L, an inorganic acid 2-80 g / L, and the solvent is water. Specific implementation cases are shown in Examples 1 to 4 and Comparative Examples 1 to 2.

[0046] The source information of some raw materials in Examples 1 to 4 and Comparative Examples 1 to 2 is as follows.

[0047] Isomeric C10 alcohol polyoxyethylene ether: molecular weight 202, sourced from Aladdin Biochemical Technology Co., Ltd., product model P304168.

[0048] Fatty alcohol-alkylene oxide copolymer: the average molecular weight is 638, sourced from Shanghai MacLean Biochemical Technology Co., Ltd., product model A794354.

[0049] Ethylene oxide propylene oxide copolymer: average molecular weight is 1100, sourced from Shanghai MacLean Biochemical Technology Co., Ltd., product model is P875724.

[0050] Isomeric fatty alcohol polyoxyethylene ether: from Sasol, the product model is MULTISO 13 / 40.

[0051] Polyoxyethylene glycol lauryl alcohol ether: molecular weight 1200, sourced from Shanghai MacLean Biochemical Technology Co., Ltd., product model F980604.

[0052] Alkylphenol polyoxyethylene ether: OP-10, molecular weight 602, from Shanghai MacLean Biochemical Technology Co., Ltd., product model O885918.

[0053] Tween: TO-40, molecular weight 1283, from Shanghai MacLean Biochemical Technology Co., Ltd., product model T819612.

[0054] Nonylphenol polyoxyethylene ether: TX-10, from Shanghai McLean Biochemical Technology Co., Ltd., product model T819588.

[0055] Note: Unless otherwise specified, the raw materials used in the present invention are all commercially available.

[0056] Example

[0057] Embodiments 1 to 4

[0058] Embodiments 1 to 4 respectively provide an acidic degreasing agent for a horizontal electroplating line of a PCB process and a method of using the same. The components of the acidic degreasing agent are shown in Table 1.

[0059] Table 1 Examples 1 to 4 Formula

[0060]

[0061]

[0062] 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 50°C.

[0063] The acidic degreasing agent provided in Example 2 was prepared as a 6% (v / v) aqueous solution for use in the degreasing treatment, and the degreasing treatment temperature was 50°C.

[0064] The acidic degreasing agent provided in Example 3 was used after being prepared into a 10% (v / v) aqueous solution during degreasing treatment, and the temperature of the degreasing treatment was 50°C.

[0065] The acidic degreasing agent provided in Example 4 was used after being prepared into a 10% (v / v) aqueous solution during degreasing treatment, and the temperature of the degreasing treatment was 50°C.

[0066] Comparative Example 1

[0067] Comparative Example 1 provides an acidic degreasing agent for a horizontal electroplating line of a PCB process and a method for using the same. The components of the acidic degreasing agent are shown in Table 2.

[0068] Table 2 Comparative Example 1 Formula

[0069]

[0070]

[0071] 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 50°C.

[0072] Comparative Example 2

[0073] Comparative Example 2 provides an acidic degreasing agent for a horizontal electroplating line of a PCB process and a method for using the same. The components of the acidic degreasing agent are shown in Table 3.

[0074] Table 3 Comparative Example 2 Formula

[0075]

[0076] 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 50°C.

[0077] The preparation methods of the acidic degreasing agents of Examples 1 to 4 and Comparative Examples 1 to 2 are the same, and the specific preparation steps include: mixing the raw materials uniformly to obtain.

[0078] Performance Testing

[0079] The acidic degreasing agent provided in Examples 1 to 4 and Comparative Examples 1 to 2 was subjected to an oil removal test. The test method is as follows: the surface of the PCB plated part is coated with triglyceride to form an oil film with a thickness of 1 μm, and then the PCB plated part is sprayed and soaked in the acidic degreasing agent prepared in Examples 1 to 4 and Comparative Examples 1 to 2 (which has been diluted into an aqueous solution according to the set use concentration) (Note: spraying and soaking are performed simultaneously), and the treatment time is 30 seconds. After the treatment, the PCB plated part is taken out and cleaned, and then washed with water and acid in turn, and then the electroplating test is simulated. The process and parameter settings during the test are shown in Table 4, and the final test results are shown in Tables 5 and Figure 1-6 .

[0080] Table 4 Processing flow

[0081] Steps and process parameters time Temperature / ℃ Degreasing 30s 50 Washing 30s 25 Pickling (specifically 5% sulfuric acid aqueous solution) 30s 25 plating 45min 40 drying 3min /

[0082] Note: The plating solution formula during the electroplating process is: electroplating brightener 8mL / L, leveling agent 15mL / L, wetting agent 15mL / L, copper sulfate pentahydrate 220g / L, sulfuric acid 50g / L, Cl - (derived from hydrochloric acid) 60ppm, the solvent is water.

[0083] The electroplating brightener is PV300B product, the leveling agent is PV-300L product, and the wetting agent is PV 300M product, all of which are sourced from Guangdong Shuocheng Technology Co., Ltd.

[0084] The foam height in the application process of the acid degreasing agent provided in Examples 1 to 4 and Comparative Examples 1 to 2, and the flatness and plating resistance of the plated surface after electroplating were observed to determine the degreasing effect of the acid degreasing agent and evaluate the operability of the jet immersion operation of the horizontal electroplating line. The specific test results are shown in Table 5.

[0085] Table 5 Performance test results

[0086]

[0087]

[0088] As shown in the test results in Table 5, the acidic degreasers obtained in Examples 1 to 4 have extremely low foam heights in the spray + immersion process, and are suitable for horizontal jet immersion degreasing. After degreasing, there is no oil film residue on the sample surface, and the surface of the plated part is glossy and smooth without roughness, and there will be no plating resistance problem. However, the acidic degreaser of Comparative Example 1 produces 50 mm thick foam in the process, which will cause foam overflow, and the surface of the plated part finally obtained is rough, and plating resistance occurs, and it cannot be applied to the horizontal jet immersion degreasing electroplating process; the foam height of the acidic degreaser of Comparative Example 2 reaches 30 mm, and there is also the problem that the foam is too high and cannot be applied to the horizontal jet immersion degreasing electroplating process, and there is a slight oil film residue after degreasing in Comparative Example 2 (15% refers to the percentage of the residual area area to the entire plated area), the surface of the plated part is rough, there is a plating resistance problem, and the degreasing effect is not good. In summary, it can be seen that only by using the acidic degreasing agent composed of the specific surfactant, inorganic acid, etc. of the present invention, can oil be removed in a very short time, and the technical effects of low foam height, good degreasing effect and no obstruction to plating can be achieved, thus meeting the electroplating process requirements of horizontal jet immersion degreasing of horizontal electroplating lines.

Claims

1. A PCB process horizontal electroplating line acidic degreasing agent, characterized in that: The raw materials for preparing the acidic degreasing agent include: 1-70 g / L of surfactant, 1-12 g / L of chelating agent, 1-50 g / L of stabilizer, 2-80 g / L of inorganic acid, and the solvent is water; The surfactant includes a nonionic surfactant or a cationic surfactant; The foam height of the acidic degreasing agent during spraying and degreasing is below 8 mm.

2. The PCB process horizontal electroplating line acidic degreasing agent according to claim 1, characterized in that: The surfactant includes a nonionic surfactant; The nonionic surfactant includes one or more combinations of isomeric fatty alcohol polyoxyethylene ethers, fatty alcohol ethoxylates, ethylene oxide propylene oxide copolymers, and fatty alcohol-alkylene oxide copolymers.

3. The PCB process horizontal electroplating line acidic degreasing agent according to claim 2, characterized in that: The nonionic surfactant comprises isomeric fatty alcohol polyoxyethylene ether, fatty alcohol-alkylene oxide copolymer and ethylene oxide propylene oxide copolymer, and the mass ratio is (1-20): (1-10): (1-10).

4. The PCB process horizontal electroplating line acidic degreasing agent according to claim 3, characterized in that: The average molecular weight of the fatty alcohol-alkylene oxide copolymer is 500-3000; Preferably, the average molecular weight of the ethylene oxide propylene oxide copolymer is 1000-2500.

5. The acidic degreasing agent for PCB process horizontal electroplating line according to claim 1, characterized in that: The stabilizer includes at least two of sodium citrate, sodium silicate, sodium metasilicate, acrylamide and soluble cellulose.

6. The acidic degreasing agent for PCB process horizontal electroplating line according to claim 5, characterized in that: The stabilizer includes sodium citrate and sodium silicate in a mass ratio of (2-7):

1.

7. The acidic degreasing agent for PCB process horizontal electroplating line according to claim 6, characterized in that: The amount of sodium citrate added to the acidic degreasing agent is 1-30 g / L; The amount of sodium silicate added to the acidic degreasing agent is 1-10 g / L.

8. The PCB process horizontal electroplating line acidic degreasing agent according to claim 1, characterized in that: The inorganic acid includes sulfuric acid, and the amount of sulfuric acid added to the acidic degreasing agent is 20-60 g / L.

9. A method for using the acidic degreasing agent for a PCB process horizontal electroplating line according to any one of claims 1 to 8, characterized in that: An acidic degreasing agent is used to perform degreasing treatment on a horizontal electroplating line of a PCB process. During the degreasing treatment, the volume addition amount of the acidic degreasing agent in the aqueous solution is 1-20%.

10. The method for using the acidic degreasing agent for the horizontal electroplating line of the PCB process according to claim 9, characterized in that: The time of the oil removal treatment is 2-60s.

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