An acidic oil removing agent, a preparation method and application thereof

Abstract

The application specifically relates to an acidic oil removing agent and a preparation method and application thereof, and belongs to the field of circuit board processing aids. The acidic oil removing agent is composed of inorganic acid, fatty acid methyl ester ethoxylate sulfonate, asparagine-choline ionic liquid, 5-hydroxymethyl furfural, sodium lignosulfonate, polymaleic anhydride and water, the composition and ratio of which are reasonable and the effect is outstanding. Compared with other oil removing agents, the acidic oil removing agent can solve the problems of poor decontamination effect and high foaming amount of the existing acidic oil removing agent, can avoid corrosion of the PCB (printed circuit board) in the oil removing process, effectively guarantees the oil removing pretreatment effect of the circuit board, is suitable for various process procedures in the PCB production which need copper surface oil removing pretreatment, and has a good application prospect in the process procedure and quality improvement of the oil removing and cleaning of the circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to an acidic degreasing agent, a preparation method and application thereof, and belongs to the field of processing aids for circuit boards. BACKGROUND

[0002] Printed circuit boards (PCB) can realize the interconnection between electronic components, and are indispensable core components of electronic products and electrical equipment. With the increasing development of technology and the improvement of consumption level, the demand for electronic products is also increasing year by year. As the core component of electronic products, the design, preparation and performance of PCB largely determine the application reliability and use satisfaction of electronic products.

[0003] At present, the process for preparing printed circuit boards in the industry is relatively complex. Before many processing procedures (such as electroplating, oxidation, phosphating) are implemented, the circuit board is usually subjected to pretreatment operation to ensure the smooth progress of subsequent processing. Generally speaking, the process for pretreating the circuit board is in the order of acid pickling, water washing, micro-etching, water washing and air drying. Among them, the acid pickling process is the first step in the pretreatment process of the circuit board, and plays a key role in the production quality of the subsequent PCB.

[0004] During the production and processing of circuit board products, a layer of oil stains will inevitably adhere to the copper surface, and at the same time, the copper surface will also be contaminated by fingerprints, oil stains, adhesive marks, oxidation points, etc. If not effectively removed, it will affect the quality of the subsequent processing plating layer or conversion film, and reduce the yield of the circuit board product. Therefore, it is necessary to perform a pretreatment operation of oil removal on the PCB.

[0005] At present, the main degreasing agents used in industry are acidic and alkaline degreasing agents. For the oil removal treatment of the copper surface of the PCB, the acidic degreasing agent is still more commonly used in the market. The purpose of acidic degreasing is to remove the oil and grease on the copper surface as well as the attached fingerprints, oil stains, oxides and other contaminants using an acidic degreasing agent. However, the existing acidic degreasing agents mostly face the problem that the removal effect of fingerprints, stubborn oil stains and other contaminants is often poor at the same time of oil removal, and cannot achieve the purpose of simultaneous removal. If multiple surfactant components are used to enhance the decontamination effect, not only the cost is high and the environmental protection is low, but also a large amount of foam is generated and adheres to the surface of the PCB, causing short circuit or open circuit of the PCB, and affecting the quality of the finished PCB.

[0006] Therefore, it is of good application prospect to develop an acidic degreasing agent with low foam and good oil removal and decontamination effect, which does not affect the performance of the circuit board. SUMMARY

[0007] In order to overcome the defects of the prior art, the acid degreasing agent can ensure the degreasing effect, solve the problems of poor dirt removal effect and high foaming amount of the prior acid degreasing agent, and effectively ensure the pretreatment effect of the circuit board.

[0008] In addition, the application further provides a preparation method of the acid degreasing agent and application of the acid degreasing agent.

[0009] The technical scheme of the application mainly adopts the following technical scheme:

[0010] An acid degreasing agent, each liter of the acid degreasing agent is composed of the following components: 30-50 mL / L of inorganic acid, 4-6 g / L of fatty acid methyl ester ethoxylate sulfonate, 8-10 g / L of asparagine-choline ionic liquid, 2.5-3.5 g / L of 5-hydroxymethyl furfural, 3.8-4.2 g / L of sodium lignosulfonate, 0.6-1.2 g / L of polymaleic anhydride, and the balance of water.

[0011] As a preferred scheme, the inorganic acid is sulfuric acid or hydrochloric acid.

[0012] As a preferred scheme, the asparagine-choline ionic liquid is prepared by using water as a solvent, choline hydroxide and asparagine as raw materials, and performing an acid-base neutralization reaction.

[0013] As a preferred scheme, the molar ratio of choline hydroxide to asparagine is 1:1.

[0014] Further preferably, the preparation process of the asparagine-choline ionic liquid is as follows: under stirring at 2-5 DEG C, choline hydroxide aqueous solution is added dropwise into asparagine aqueous solution to perform a neutralization reaction for 32-40 h, after the reaction, dehydration is performed under reduced pressure, then redissolution is performed by using acetonitrile as a solvent, acetonitrile is removed under reduced pressure, and finally drying is performed to obtain the asparagine-choline ionic liquid.

[0015] As a preferred scheme, each liter of the acid degreasing agent is composed of the following components: 40 mL / L of inorganic acid, 5 g / L of fatty acid methyl ester ethoxylate sulfonate, 9 g / L of asparagine-choline ionic liquid, 3 g / L of 5-hydroxymethyl furfural, 4 g / L of sodium lignosulfonate, 0.9 g / L of polymaleic anhydride, and the balance of water.

[0016] The preparation method of the acid degreasing agent includes the following steps:

[0017] In the container, first add less than the formula amount of water, then add the formula amount of inorganic acid under stirring, mix uniformly, then add the formula amount of fatty acid methyl ester ethoxylate sulfonate, aspartame-choline ionic liquid, 5-hydroxymethyl furfural, sodium lignosulfonate, polymaleic anhydride, mix uniformly under stirring, then add the remaining amount of water and stir, finally filter and prepare for use.

[0018] As a preferred scheme, the less than the formula amount of water is 60% to 80% of the total mass of water.

[0019] As a preferred scheme, the water is deionized water or pure water.

[0020] An application of the above-mentioned acidic degreasing agent, in particular, in the application of printed circuit board oil removal treatment; the oil removal treatment is to soak the printed circuit board at 20 to 35 DEG C for 30 to 50 s.

[0021] As a preferred scheme, the oil removal treatment is to soak the printed circuit board at 30 DEG C for 40 s.

[0022] The acidic degreasing agent of the present application uses inorganic acid, fatty acid methyl ester ethoxylate sulfonate, aspartame-choline ionic liquid, 5-hydroxymethyl furfural, sodium lignosulfonate, polymaleic anhydride and water as the degreasing agent composition, which is reasonable in composition and ratio and outstanding in effect. Among them, the fatty acid methyl ester ethoxylate sulfonate belongs to a low-foaming active component, but compared with common surfactants, its decontamination effect is relatively poor. The present application further introduces aspartame-choline ionic liquid on the basis of fatty acid methyl ester ethoxylate sulfonate and inorganic acid, which can utilize its rich functional groups and action sites to play the role of enhancing PCB copper surface wetting and slowing down copper surface corrosion, so as to realize oil removal while improving the decontamination effect, and make the degreasing agent have the comprehensive performance of degreasing, decontamination and corrosion inhibition. In addition, the present application uses 5-hydroxymethyl furfural to further slow down the corrosion of PCB copper surface, and uses sodium lignosulfonate and polymaleic anhydride in combination to enhance the dispersibility and stability of the acidic degreasing agent system.

[0023] Therefore, the beneficial effects of the above technical solutions of the present application mainly lie in:

[0024] (1) The oil stains can be quickly and effectively removed from the PCB copper surface, and the cleaning effect is good;

[0025] (2) The foaming amount is small, easy to wash and clean, and does not adhere to the circuit board;

[0026] (3) The PCB surface is not corroded, and the PCB is not damaged;

[0027] (4) The raw material composition is simple, and especially the asparagine-choline ionic liquid is a green additive, and has good degradability, so that the demand of the circuit board processing aid for green and sustainable development can be met.

[0028] Therefore, the acid oil removing agent has good oil removing and stain removing effects while having low foaming, does not cause corrosion damage to the PCB board, can be effectively applied to various process procedures of copper surface oil removing pretreatment in PCB production, and has good promotion and application prospects in the process procedure and quality improvement of circuit board oil removing and cleaning. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the technical scheme of the present application is described in detail below in combination with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the protection scope of the present application.

[0030] In the following examples, the fatty acid methyl ester ethoxylate sulfonate (FMES) is sodium fatty acid methyl ester ethoxylate sulfonate, model number QC-YC0049. The mass concentration of choline in the aqueous choline hydroxide solution is 45wt%.

[0031] Example 1

[0032] An acid oil removing agent, each liter of the acid oil removing agent is composed of the following components: inorganic acid 40mL / L, fatty acid methyl ester ethoxylate sulfonate 5g / L, asparagine-choline ionic liquid 9g / L, 5-hydroxymethyl furfural 3g / L, sodium lignosulfonate 4g / L, polymaleic anhydride 0.9g / L, and water in balance.

[0033] The inorganic acid is 98% sulfuric acid. The asparagine-choline ionic liquid is prepared by using deionized water as a solvent, choline hydroxide and asparagine as raw materials, and performing an acid-base neutralization reaction; the molar ratio of choline hydroxide to asparagine is 1:1. The specific process is as follows: asparagine is dissolved in deionized water to obtain an asparagine aqueous solution. Under stirring conditions at 4℃, the choline hydroxide aqueous solution (45wt%) is slowly added dropwise into the aqueous solution containing an equal molar amount of asparagine, and after the dropwise addition is completed, the neutralization reaction is performed under stirring conditions at room temperature for 36h. After the reaction, vacuum drying is performed to remove water, then the asparagine-choline ionic liquid is redissolved by using acetonitrile as a solvent, acetonitrile is removed under reduced pressure, and finally vacuum drying is performed, and the asparagine-choline ionic liquid is placed in a desiccator for standby, i.e. the asparagine-choline ionic liquid is obtained.

[0034] The preparation method of the acid oil removing agent described above comprises the following steps:

[0035] In the container first add 70% of the formula amount of deionized water, then under stirring conditions, add the formula amount of inorganic acid and mix well, then add the formula amount of fatty acid methyl ester ethoxylate sulfonate, aspartame-choline ionic liquid, 5-hydroxymethyl furfural, sodium lignosulfonate, and polymaleic anhydride, mix well under stirring, then add the remaining amount of deionized water to stir and set the volume, finally filter and reserve.

[0036] Example 2

[0037] An acidic degreasing agent, consisting of the following components per liter of acidic degreasing agent: inorganic acid 30 mL / L, fatty acid methyl ester ethoxylate sulfonate 6 g / L, aspartame-choline ionic liquid 10 g / L, 5-hydroxymethyl furfural 3 g / L, sodium lignosulfonate 4 g / L, and polymaleic anhydride 0.9 g / L, with the balance being water.

[0038] The inorganic acid is 98% sulfuric acid. The aspartame-choline ionic liquid is prepared by using deionized water as the solvent, choline hydroxide and aspartame as the raw materials, and performing an acid-base neutralization reaction. The molar ratio of choline hydroxide to aspartame is 1:1. The specific process is as follows: aspartame is dissolved in deionized water to obtain an aspartame aqueous solution. Under stirring conditions at 4°C, choline hydroxide aqueous solution (45 wt%) is slowly added dropwise to the aqueous solution containing an equal molar amount of aspartame. After the dropwise addition is completed, the neutralization reaction is performed under stirring conditions at room temperature for 36 h. After the reaction, vacuum drying is performed to remove water. Then, acetonitrile is used as the solvent for re-dissolution. After that, acetonitrile is removed under reduced pressure. Finally, vacuum drying is performed, and the product is stored in a desiccator for later use, thereby obtaining the aspartame-choline ionic liquid.

[0039] The preparation method of the above-mentioned acidic degreasing agent comprises the following steps:

[0040] In the container first add 70% of the formula amount of deionized water, then under stirring conditions, add the formula amount of inorganic acid and mix well, then add the formula amount of fatty acid methyl ester ethoxylate sulfonate, aspartame-choline ionic liquid, 5-hydroxymethyl furfural, sodium lignosulfonate, and polymaleic anhydride, mix well under stirring, then add the remaining amount of deionized water to stir and set the volume, finally filter and reserve.

[0041] Example 3

[0042] An acidic degreasing agent, consisting of the following components per liter of acidic degreasing agent: inorganic acid 30 mL / L, fatty acid methyl ester ethoxylate sulfonate 6 g / L, aspartame-choline ionic liquid 10 g / L, 5-hydroxymethyl furfural 3 g / L, sodium lignosulfonate 4 g / L, and polymaleic anhydride 0.9 g / L, with the balance being water.

[0043] The inorganic acid is 98% sulfuric acid. The asparagine-choline ionic liquid is prepared by taking deionized water as a solvent, taking choline hydroxide and asparagine as raw materials, and performing an acid-base neutralization reaction. The molar ratio of choline hydroxide to asparagine is 1:1. The specific process is as follows: asparagine is dissolved in deionized water to obtain an asparagine aqueous solution. Under stirring at 4°C, choline hydroxide aqueous solution (45wt%) is slowly added dropwise into the aqueous solution containing an equal molar amount of asparagine. After the dropwise addition is completed, the neutralization reaction is performed under stirring at room temperature for 36 hours. After the reaction, vacuum drying is performed to remove water. Then, acetonitrile is used as a solvent for redissolution. Acetonitrile is removed under reduced pressure. Finally, vacuum drying is performed, and the product is placed in a desiccator for standby, thereby obtaining the asparagine-choline ionic liquid.

[0044] The preparation method of the acid oil removal agent comprises the following steps:

[0045] In a container, 70% of the formula amount of deionized water is first added, then the formula amount of inorganic acid is added under stirring, and then the formula amount of fatty acid methyl ester ethoxylate sulfonate, asparagine-choline ionic liquid, 5-hydroxymethylfurfural, sodium lignosulfonate, and polymaleic anhydride are added and stirred to mix uniformly. Then, the remaining amount of deionized water is added for stirring and volume setting. Finally, filtration is performed, and the product is ready for use.

[0046] Comparative Example 1

[0047] The acid oil removal agent of the present comparative example is a commercially available KBX-603 acid oil removal agent.

[0048] Comparative Example 2

[0049] The acid oil removal agent of the present comparative example is composed of the following components per liter of acid oil removal agent: inorganic acid 40 mL / L, fatty alcohol polyoxyethylene ether 5 g / L, asparagine-choline ionic liquid 9 g / L, 5-hydroxymethylfurfural 3 g / L, sodium lignosulfonate 4 g / L, and polymaleic anhydride 0.9 g / L, with the balance being water.

[0050] Comparative Example 3

[0051] The acid oil removal agent of the present comparative example is composed of the following components per liter of acid oil removal agent: inorganic acid 40 mL / L, fatty acid methyl ester ethoxylate sulfonate 5 g / L, 5-hydroxymethylfurfural 3 g / L, sodium lignosulfonate 4 g / L, and polymaleic anhydride 0.9 g / L, with the balance being water.

[0052] Comparative Example 4

[0053] The acid degreaser of the present comparative example is composed of the following components per liter of the acid degreaser: inorganic acid 40 mL / L, fatty acid methyl ester ethoxylate sulfonate 5 g / L, glutamine-choline ionic liquid 9 g / L, 5-hydroxymethyl furfural 3 g / L, sodium lignosulfonate 4 g / L, polymaleic anhydride 0.9 g / L, and water in balance. The preparation process of the glutamine-choline ionic liquid is carried out with reference to Example 1.

[0054] Comparative Example 5

[0055] The acid degreaser of the present comparative example is composed of the following components per liter of the acid degreaser: inorganic acid 40 mL / L, fatty acid methyl ester ethoxylate sulfonate 5 g / L, glutamine-choline ionic liquid 9 g / L, 5-hydroxymethyl furfural 3 g / L, sodium lignosulfonate 4 g / L, polymaleic anhydride 0.9 g / L, and water in balance. The preparation process of the glutamine-choline ionic liquid is carried out with reference to Example 1.

[0056] Performance test and evaluation

[0057] The processed PCB circuit board sample is cut into a sample of 5 cm x 5 cm, and then the corners are roughened by sandpaper. In addition to the conventional oil stains, the surface of the processed circuit board also has uniform adhesive marks, fingerprints, oil stains, oxidation points and other difficult-to-remove pollutants. After the sample is processed, the acid degreasers of Examples 1-3 and Comparative Examples 1-5 of the present application are used to treat the circuit board sample. The degreasing process is to immerse the circuit board sample in the acid degreaser with a pre-adjusted temperature (30°C) for a predetermined time (40s), then wash it with deionized water and ethanol for 30s, and then dry it for subsequent performance evaluation.

[0058] I. Evaluation of degreasing effect: five-point scoring system. Determine whether there are oil film and other light oil stains on the surface of the circuit board after treatment with the degreasing agent. Among them, 5 points is the best, which means that there are no oil film and other light oil stains on the surface of the circuit board after treatment with the acid degreasing agent; 4, 3, 2 points means that there are a small amount, a small amount, and a large amount of oil film and other light oil stains on the surface of the circuit board after treatment with the acid degreasing agent; 0 points is the worst, which means that there are a large amount of oil film and other light oil stains on the surface of the circuit board after treatment.

[0059] II. Foam amount evaluation: five-point scoring system. The amount of bubbles generated by the acidic degreasing agent during the degreasing process and the amount of bubbles remaining on the surface of the circuit board after degreasing are scored and evaluated. Among them, 5 points is the best, which means that no large bubbles are generated during the degreasing process and there is no residual bubble on the surface of the circuit board; 4 points means that a small amount of large bubbles are generated during the degreasing process, but there is no residual bubble on the surface of the circuit board; 3 points means that a small amount of large bubbles are generated during the degreasing process, and there is a small amount of residual bubble on the surface of the circuit board; 2 points means that a large amount of large bubbles are generated during the degreasing process, and there is a small amount of residual bubble on the surface of the circuit board; 0 points is the worst, which means that a large amount of large bubbles are generated during the degreasing process, and there is a large amount of residual bubble on the surface of the circuit board.

[0060] III. Cleanliness evaluation: five-point scoring system. Determine whether there are stubborn stains such as fingerprints, oxidation points, and oil stains remaining on the surface of the circuit board after treatment with the acidic degreasing agent. Among them, 5 points is the best, which means that there are no fingerprints, oxidation points, and oil stains on the surface of the circuit board after treatment with the acidic degreasing agent; 4, 3, and 2 points mean that there are a small amount, a small amount, or a large amount of fingerprints, oxidation points, and oil stains on the surface of the circuit board after treatment with the acidic degreasing agent; 0 points is the worst, which means that there are a large amount of obvious fingerprints, oxidation points, and oil stains on the surface of the circuit board after treatment.

[0061] IV. Corrosion performance evaluation: five-point scoring system. Determine whether there is corrosion on the surface of the circuit board after treatment with the degreasing agent. Among them, 5 points is the best, which means that there is no corrosion on the surface of the circuit board after treatment with the acidic degreasing agent; 4, 3, and 2 points mean that there are a small amount, a small amount, and a large amount of corrosion on the surface of the circuit board after treatment with the acidic degreasing agent; 0 points is the worst, which means that there is a large amount of corrosion on the surface of the circuit board after treatment.

[0062] The above results are shown in Table 1.

[0063] Table 1: Performance of the acidic degreasing agent of Examples 1-3 and Comparative Examples 1-5

[0064] Test group Oil removal effect Foam amount Cleanliness Corrosion condition Total score Example 1 5 5 5 5 20 Example 2 5 5 5 5 20 Example 3 5 5 4 5 19 Comparative Example 1 5 3 2 3 13 Comparative Example 2 5 2 4 5 16 Comparative Example 3 5 5 3 2 15 Comparative Example 4 5 5 3 4 17 Comparative Example 5 5 5 3 3 16

[0065] As can be seen from the results in Table 1, the acidic degreasing agent provided by the present application can solve the problems of poor degreasing effect and high foaming amount compared to other degreasing agents, while ensuring the degreasing effect, and can avoid corrosion of the PCB, effectively ensure the degreasing pretreatment effect of the circuit board, and can be effectively applied to various process steps of copper surface degreasing pretreatment in PCB production, and has good application prospect in the process of degreasing and cleaning of the circuit board and quality improvement.

Claims

1. An acidic degreasing agent, characterized in that, Each liter of acidic degreasing agent consists of the following components: 30-50 mL / L of inorganic acid, 4-6 g / L of fatty acid methyl ester ethoxylate sulfonate, 8-10 g / L of asparagine-choline ionic liquid, 2.5-3.5 g / L of 5-hydroxymethylfurfural, 3.8-4.2 g / L of sodium lignosulfonate, 0.6-1.2 g / L of polymaleic anhydride, and water as the balance. The preparation process of the asparagine-choline ionic liquid is as follows: under stirring conditions at 2~5℃, an aqueous solution of choline hydroxide is added dropwise to an aqueous solution of asparagine for a neutralization reaction for 32~40h. After the reaction, the liquid is dehydrated under reduced pressure, then reconstituted using acetonitrile as a solvent, and then the acetonitrile is removed under reduced pressure. Finally, the liquid is dried to obtain the asparagine-choline ionic liquid.

2. The acidic degreasing agent according to claim 1, characterized in that, The inorganic acid is sulfuric acid or hydrochloric acid.

3. The acidic degreasing agent according to claim 1, characterized in that, The molar ratio of choline hydroxide to asparagine is 1:

1.

4. The acidic degreasing agent according to claim 1, characterized in that, Each liter of acidic degreasing agent consists of the following components: 40 mL / L inorganic acid, 5 g / L fatty acid methyl ester ethoxylate sulfonate, 9 g / L asparagine-choline ionic liquid, 3 g / L 5-hydroxymethylfurfural, 4 g / L sodium lignosulfonate, 0.9 g / L polymaleic anhydride, and water as the balance.

5. The method for preparing the acidic degreasing agent according to any one of claims 1 to 4, characterized in that, Includes the following steps: First, add water to the container in a volume lower than the formula amount. Then, under stirring conditions, add the inorganic acid in the formula amount and mix well. Next, add the fatty acid methyl ester ethoxylate sulfonate, asparagine-choline ionic liquid, 5-hydroxymethylfurfural, sodium lignosulfonate, and polymaleic anhydride in the formula amount and stir until well mixed. Then, add the remaining water and stir. Finally, filter and set aside.

6. The method for preparing the acidic degreasing agent according to claim 5, characterized in that, The amount of water below the prescribed amount is 60% to 80% of the total mass of water used.

7. The application of an acidic degreasing agent as described in any one of claims 1 to 4, characterized in that, Application in degreasing treatment of printed circuit boards; the degreasing treatment involves immersing the printed circuit board at 20~35℃ for 30~50 seconds.

8. The application of the acidic degreasing agent according to claim 7, characterized in that, The degreasing treatment involves immersing the printed circuit board at 30°C for 40 seconds.