High-weldability circuit board surface treatment liquid medicine and preparation method thereof

Abstract

The invention discloses a high-weldability circuit board surface treatment chemical liquid and a preparation method thereof, and the formula comprises 3, 5-dichloropyridine-4-formaldehyde, 2-(3, 4-dichlorobenzyl) benzimidazole, 1-phenyl-1, 2-propanedione, acetic acid, ethyl acetate, copper chloride, n-heptanoic acid, an antioxidant and ammonia water; the preparation method comprises the following steps: step 1, preparing and pretreating materials; step 2, mixing reaction; step 3, solvent recovery; step 4, separating out and neutralizing a product; step five, drying and crude product treatment; and 6, refining and preparing a finished product. A pyridine group is introduced into an imidazole compound to prepare the circuit board surface treatment liquid medicine, and the liquid medicine has more excellent water solubility and can be uniformly dispersed in a solvent, so that an OSP solution is more stable, a flat and compact film layer can be generated on the surface of a circuit board, and in the welding process, the surface of the circuit board is not damaged. The film layer can be used as a bridge between the solder and the circuit board.

Description

Technical Field

[0001] The invention relates to the technical field of circuit board surface treatment, in particular to a circuit board surface treatment liquid with high solderability and a preparation method thereof. Background Art

[0002] In the circuit board welding process, circuit board surface treatment liquid is usually used to enhance the circuit board surface welding performance, improve welding quality and reliability. Among them, OSP (organic solder preservative) liquid is a high-performance copper surface solder preservative specially used for circuit boards. It is a high-performance new generation environmentally friendly product that replaces hot air leveling and other surface treatments. When the circuit board is treated with OSP liquid, the copper surface and each perforation are covered and protected by a layer of solid organic film. This film can maintain the flatness of the copper surface and prevent the copper surface from being oxidized. At the same time, it ensures that the metal copper surface still maintains the original lead-tin welding ability after surface mount welding and perforation wave soldering.

[0003] The existing circuit board surface treatment liquid has the following defects: First, as a kind of commonly used OSP components, imidazole and its derivatives have poor water solubility, which is a problem that cannot be ignored. Due to poor water solubility, these compounds are difficult to disperse evenly in water during the preparation process, resulting in poor stability of the prepared OSP solution. This instability may manifest as turbidity of the solution, precipitation of solid matter, etc., which seriously affects the effect of OSP film formation. The unevenness and incompleteness of the film formation will reduce the welding performance of the film layer, making the circuit board prone to problems such as poor welding and cold welding during the welding process; Second, the traditional film-forming agent produces The organic solder preservative film has poor heat resistance. Under the high heating conditions of multiple reflow soldering, the OSP film is often unable to withstand the continuous impact of the high temperature environment and is prone to decomposition. This decomposition will not only cause the pad surface to be re-exposed to the air, thereby accelerating its oxidation process, but also cause a series of welding problems, such as poor welding and cold soldering, which seriously weaken the bonding strength between the pad and the components, thereby affecting the welding performance and long-term reliability of the entire circuit board; third, the preparation process is relatively complex and the cost is high, which not only increases the operational difficulty and time cost in the production process, but also increases the production cost of the product. Summary of the invention

[0004] The object of the present invention is to provide a circuit board surface treatment solution with high solderability and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a circuit board surface treatment liquid with high solderability, the formula of which includes: 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole, 1-phenyl-1,2-propanedione, acetic acid, ethyl acetate, cupric chloride, n-heptanoic acid, an antioxidant and ammonia water, wherein the proportions of the components are: 5% to 10% of 3,5-dichloropyridine-4-carboxaldehyde, 4% to 6% of 2-(3,4-dichlorobenzyl)benzimidazole, 6% to 9% of 1-phenyl-1,2-propanedione, 12% to 18% of acetic acid, 10% to 15% of ethyl acetate, 5% to 7% of cupric chloride, 3% to 5% of n-heptanoic acid, 1% to 1.5% of an antioxidant and 35% to 45% of ammonia water.

[0006] As a further technical solution of the present invention, the mass percentages of the components are: 7% 3,5-dichloropyridine-4-carboxaldehyde, 5% 2-(3,4-dichlorobenzyl)benzimidazole, 8% 1-phenyl-1,2-propanedione, 15% acetic acid, 15% ethyl acetate, 5% cupric chloride, 5% n-heptanoic acid, 1% antioxidant and 39% ammonia water.

[0007] As a further technical solution of the present invention, the mass percentages of the components are: 5% of 3,5-dichloropyridine-4-carboxaldehyde, 4% of 2-(3,4-dichlorobenzyl)benzimidazole, 9% of 1-phenyl-1,2-propanedione, 18% of acetic acid, 12% of ethyl acetate, 6% of cupric chloride, 4.5% of n-heptanoic acid, 1.5% of antioxidant and 40% of aqueous ammonia.

[0008] As a further technical solution of the present invention, the antioxidant is one of vitamin C and vitamin E.

[0009] A method for preparing a circuit board surface treatment liquid with high solderability, comprising the steps of: first, material preparation and pretreatment; second, mixing reaction; third, solvent recovery; fourth, product precipitation and neutralization; fifth, drying and crude product treatment; and sixth, refining and finished product preparation.

[0010] In the above step 1, raw materials are prepared according to the recipe and ensured to meet the production standards, and the raw materials are pre-treated before preparation;

[0011] In the above step 2, the raw materials are mixed for initial reaction, and an antioxidant and copper chloride are added;

[0012] In the above step 3, the excess solvent is recovered and reused subsequently;

[0013] In the above step 4, the target product is precipitated and the pH is adjusted;

[0014] In the above step 5, the filtered white solid is drained to remove excess water, and then dried to obtain an off-white crude product;

[0015] In the above step six, the finished product is purified by recrystallization, and the performance index of the finished product is tested.

[0016] As a further technical solution of the present invention, in the step 2, 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole and 1-phenyl-1,2-propanedione are added to the solvent according to the formula ratio. The solvent is prepared by mixing acetic acid, ethyl acetate and n-heptanoic acid to provide suitable solubility and reaction environment to promote the smooth progress of the subsequent chemical reaction. The mixture is stirred and heated to 85°C, and refluxed for 2 to 3 hours. The reflux is conducive to the full mixing and reaction between the reactants and prevents the loss of solvent by volatilization. During the process, thin layer chromatography is used to monitor the progress of the reaction to ensure that the raw materials are fully reacted.

[0017] As a further technical solution of the present invention, in the step 2, by comparing the changes in the TLC spectrum before and after the reaction, it can be judged whether the raw material has been fully reacted. If the raw material spots disappear or are significantly reduced, and the product spots are clearly discernible, it means that the reaction is nearly complete. After the raw material is fully reacted, the heating is stopped and the mixture is cooled to 65° C., and then the antioxidant and cupric chloride are added to the reaction system according to the formula ratio. Stirring should be continued during the addition process to ensure that these additives can be evenly dispersed in the drug solution.

[0018] As a further technical solution of the present invention, in step three, after the reaction solution is cooled to room temperature, a rotary evaporator is used to evaporate and recover about 1 / 2 volume of the solvent, and the recovered solvent can be used for subsequent batches of production or other treatments.

[0019] As a further technical solution of the present invention, in step 4, the remaining reaction liquid is slowly added into pure water and stirred. During the process, a large amount of milky white solid is precipitated. After cooling to room temperature, ammonia water is added to neutralize the solution to a pH value between 7.5 and 8.0. The white solid is filtered out and washed with pure water for multiple times to remove impurities.

[0020] As a further technical solution of the present invention, in step six, the crude product is recrystallized with acetonitrile, and the process is repeated twice to improve the purity and crystallinity of the product. The recrystallized solid is filtered, washed and dried to obtain a high-purity white solid finished product. The melting point and purity index of the finished product are tested to ensure that the requirements for surface treatment of high-weldability circuit boards are met.

[0021] Compared with the prior art, the invention has the following beneficial effects: the invention introduces a pyridine group into an imidazole compound to prepare a circuit board surface treatment liquid, which has better water solubility and can be evenly dispersed in a solvent, so that the OSP solution is more stable, and a flat and dense film layer can be generated on the surface of the circuit board. During the welding process, this film layer can serve as a bridge between the solder and the circuit board to promote the close bonding between the solder and the circuit board, thereby improving the reliability and stability of welding; and by adding 2-(3,4-dichlorobenzyl)benzimidazole, one end of Cl contained in the component molecule can be adsorbed with copper ions to form a complex, and these complexes can be mutually adsorbed and bonded to form a solid protective layer, and this protective layer can remain stable under high-temperature welding conditions and is not easy to decompose, thereby ensuring the long-term reliability of the circuit board welding performance, which is of great significance for improving the high-temperature resistance of the circuit board and extending its service life, and has the advantages of simple preparation process and low cost, which is conducive to large-scale promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1 , a technical solution provided by the present invention:

[0025] Example 1

[0026] A circuit board surface treatment liquid with high solderability, the formula of which includes: 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole, 1-phenyl-1,2-propanedione, acetic acid, ethyl acetate, cupric chloride, n-heptanoic acid, antioxidant and ammonia water, the proportions of the components are: 7% of 3,5-dichloropyridine-4-carboxaldehyde, 5% of 2-(3,4-dichlorobenzyl)benzimidazole, 8% of 1-phenyl-1,2-propanedione, 15% of acetic acid, 15% of ethyl acetate, 5% of cupric chloride, 5% of n-heptanoic acid, 1% of antioxidant and 39% of ammonia water; the antioxidant is one of vitamin C and vitamin E;

[0027] A method for preparing a circuit board surface treatment liquid with high solderability, comprising the steps of: first, material preparation and pretreatment; second, mixing reaction; third, solvent recovery; fourth, product precipitation and neutralization; fifth, drying and crude product treatment; and sixth, refining and finished product preparation.

[0028] In the above step 1, raw materials are prepared according to the recipe and ensured to meet the production standards, and the raw materials are pre-treated before preparation;

[0029] In the above step 2, 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole and 1-phenyl-1,2-propanedione are added to the solvent according to the formula ratio. The solvent is prepared by mixing acetic acid, ethyl acetate and n-heptanoic acid to provide suitable solubility and reaction environment to promote the smooth progress of the subsequent chemical reaction. The mixture is stirred and heated to 85°C, and the mixture is kept warm and refluxed for 2 to 3 hours. The warm reflux is conducive to the full mixing and reaction between the reactants, and the loss of solvent volatilization is prevented. During the process, thin layer chromatography is used to monitor the progress of the reaction to ensure that the raw materials are fully reacted. By comparing the changes in the TLC spectrum before and after the reaction, it can be judged whether the raw materials have been fully reacted. If the raw material spots disappear or are significantly reduced, and the product spots are clearly distinguishable, it means that the reaction is nearly complete. After the raw materials are fully reacted, the heating is stopped and the mixture is cooled to 65°C. Then, the antioxidant and cupric chloride are added to the reaction system according to the formula ratio. Stirring should be continued during the addition process to ensure that these additives can be evenly dispersed in the drug solution.

[0030] In the above step 3, after the reaction solution is cooled to room temperature, about 1 / 2 volume of the solvent is evaporated and recovered using a rotary evaporator, and the recovered solvent can be used for subsequent batch production or other treatments;

[0031] In the above step 4, the remaining reaction solution is slowly added into pure water and stirred, during which a large amount of milky white solid is precipitated. After cooling to room temperature, ammonia water is added to neutralize the pH value to between 7.5 and 8.0, the white solid is filtered out, and washed with pure water for multiple times to remove impurities;

[0032] In the above step 5, the filtered white solid is drained to remove excess water, and then dried to obtain an off-white crude product;

[0033] In the above step six, the crude product is recrystallized with acetonitrile, and the process is repeated twice to improve the purity and crystallinity of the product. The recrystallized solid is filtered, washed and dried to obtain a high-purity white solid finished product. The melting point and purity index of the finished product are tested to ensure that it meets the requirements for surface treatment of high-weldability circuit boards.

[0034] Example 2

[0035] A circuit board surface treatment liquid with high solderability comprises: 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole, 1-phenyl-1,2-propanedione, acetic acid, ethyl acetate, cupric chloride, n-heptanoic acid, an antioxidant and aqueous ammonia. The proportions of the components are: 5% of 3,5-dichloropyridine-4-carboxaldehyde, 4% of 2-(3,4-dichlorobenzyl)benzimidazole, 9% of 1-phenyl-1,2-propanedione, 18% of acetic acid, 12% of ethyl acetate, 6% of cupric chloride, 4.5% of n-heptanoic acid, 1.5% of an antioxidant and 40% of aqueous ammonia. The antioxidant is one of vitamin C and vitamin E. The preparation method is the same as that of Example 1.

[0036] Example 3

[0037] A circuit board surface treatment liquid with high solderability, the formula of which includes: 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole, 1-phenyl-1,2-propanedione, acetic acid, ethyl acetate, cupric chloride, n-heptanoic acid, an antioxidant and ammonia water, the proportions of the components are: 6% of 3,5-dichloropyridine-4-carboxaldehyde, 6% of 2-(3,4-dichlorobenzyl)benzimidazole, 7% of 1-phenyl-1,2-propanedione, 18% of acetic acid, 11% of ethyl acetate, 7% of cupric chloride, 3% of n-heptanoic acid, 1% of an antioxidant and 41% of ammonia water; the antioxidant is one of vitamin C and vitamin E, and the preparation method thereof is consistent with that in Example 1.

[0038] The specific composition ratios of each embodiment are shown in the following table:

[0039]

[0040]

[0041] Based on the above, the advantages of the present invention are: the present invention introduces a pyridine group into an imidazole compound to prepare a circuit board surface treatment solution, which has better water solubility and can be evenly dispersed in a solvent, making the OSP solution more stable, and can form a flat and dense film layer on the surface of the circuit board. This film layer can not only effectively isolate the corrosion of the external environment to the circuit board, but also significantly improve the welding performance of the circuit board. During the welding process, this film layer can serve as a bridge between the solder and the circuit board, promote the close bonding between the solder and the circuit board, thereby improving the reliability and stability of welding; and by adding 2-(3,4-dichlorobenzyl)benzimidazole, the composition One end of Cl contained in the molecular molecule can be adsorbed with copper ions to form a complex, and these complexes can be adsorbed and combined with each other to form a solid protective layer. This protective layer can remain stable under high-temperature welding conditions and is not easy to decompose, thereby ensuring the long-term reliability of the circuit board welding performance, which is of great significance for improving the high-temperature resistance of the circuit board and extending its service life. The present invention also has the advantages of simple preparation process and low cost. Compared with traditional circuit board surface treatment liquid, the preparation process of the present invention is more concise and clear, does not require complex equipment and cumbersome operating steps, thereby reducing production costs, and is therefore also conducive to large-scale promotion and use.

[0042] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A circuit board surface treatment liquid with high solderability, the formula comprising: 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole, 1-phenyl-1,2-propanedione, acetic acid, ethyl acetate, cupric chloride, n-heptanoic acid, an antioxidant and aqueous ammonia, characterized in that the proportions of the components are: 5% to 10% of 3,5-dichloropyridine-4-carboxaldehyde, 4% to 6% of 2-(3,4-dichlorobenzyl)benzimidazole, 6% to 9% of 1-phenyl-1,2-propanedione, 12% to 18% of acetic acid, 10% to 15% of ethyl acetate, 5% to 7% of cupric chloride, 3% to 5% of n-heptanoic acid, 1% to 1.5% of an antioxidant and 35% to 45% of aqueous ammonia.

2. The circuit board surface treatment liquid with high solderability according to claim 1, characterized in that: The mass percentages of the components are: 7% of 3,5-dichloropyridine-4-carboxaldehyde, 5% of 2-(3,4-dichlorobenzyl)benzimidazole, 8% of 1-phenyl-1,2-propanedione, 15% of acetic acid, 15% of ethyl acetate, 5% of cupric chloride, 5% of n-heptanoic acid, 1% of antioxidant and 39% of aqueous ammonia.

3. The circuit board surface treatment liquid with high solderability according to claim 1, characterized in that: The mass percentages of the components are: 5% of 3,5-dichloropyridine-4-carboxaldehyde, 4% of 2-(3,4-dichlorobenzyl)benzimidazole, 9% of 1-phenyl-1,2-propanedione, 18% of acetic acid, 12% of ethyl acetate, 6% of cupric chloride, 4.5% of n-heptanoic acid, 1.5% of antioxidant and 40% of aqueous ammonia.

4. The circuit board surface treatment liquid with high solderability according to claim 3, characterized in that: The antioxidant is one of vitamin C and vitamin E.

5. A method for preparing a circuit board surface treatment liquid with high solderability, comprising step 1, material preparation and pretreatment; step 2, mixing reaction; step 3, solvent recovery; step 4, product precipitation and neutralization; step 5, drying and crude product treatment; step 6, refining and finished product preparation; characterized in that: In the above step 1, raw materials are prepared according to the recipe and ensured to meet the production standards, and the raw materials are pre-treated before preparation; In the above step 2, the raw materials are mixed for initial reaction, and an antioxidant and copper chloride are added; In the above step 3, the excess solvent is recovered and reused subsequently; In the above step 4, the target product is precipitated and the pH is adjusted; In the above step 5, the filtered white solid is drained to remove excess water, and then dried to obtain an off-white crude product; In the above step six, the finished product is purified by recrystallization, and the performance index of the finished product is tested.

6. The method for preparing a circuit board surface treatment liquid with high solderability according to claim 5, characterized in that: In the step 2, 3,5-dichloropyridine-4-carboxaldehyde, 2-(3,4-dichlorobenzyl)benzimidazole and 1-phenyl-1,2-propanedione are added to a solvent according to a formula ratio. The solvent is prepared by mixing acetic acid, ethyl acetate and n-heptanoic acid to provide suitable solubility and reaction environment, promote the smooth progress of subsequent chemical reactions, stir and heat to 85° C., and reflux for 2 to 3 hours. The reflux is conducive to the full mixing and reaction between the reactants and prevents the loss of solvent by volatilization. During the process, thin layer chromatography is used to monitor the progress of the reaction to ensure that the raw materials are fully reacted.

7. The method for preparing a circuit board surface treatment liquid with high solderability according to claim 6, characterized in that: In the step 2, by comparing the changes in the TLC spectrum before and after the reaction, it can be judged whether the raw material has been fully reacted. If the raw material spots disappear or are significantly reduced, and the product spots are clearly discernible, it means that the reaction is nearly complete. After the raw material is fully reacted, the heating is stopped and the mixture is cooled to 65° C., and then the antioxidant and cupric chloride are added to the reaction system according to the formula ratio. Stirring should be continued during the addition process to ensure that these additives can be evenly dispersed in the drug solution.

8. The method for preparing a circuit board surface treatment liquid with high solderability according to claim 5, characterized in that: In the step 3, after the reaction solution is cooled to room temperature, a rotary evaporator is used to evaporate and recover about 1 / 2 volume of the solvent, and the recovered solvent can be used for subsequent batch production or other treatments.

9. The method for preparing a circuit board surface treatment liquid with high solderability according to claim 5, characterized in that: In step 4, the remaining reaction liquid is slowly added into pure water and stirred. During the process, a large amount of milky white solid is precipitated. After cooling to room temperature, ammonia water is added to neutralize the solution to a pH value between 7.5 and 8.

0. The white solid is filtered out and washed with pure water for multiple times to remove impurities.

10. The method for preparing a circuit board surface treatment liquid with high solderability according to claim 5, characterized in that: In the step six, the crude product is recrystallized with acetonitrile, and the process is repeated twice to improve the purity and crystallinity of the product. The recrystallized solid is filtered, washed and dried to obtain a high-purity white solid finished product. The melting point and purity index of the finished product are tested to ensure that the requirements for surface treatment of high-weldability circuit boards are met.

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