A fluorine-containing benzimidazole derivative organic fluxing protective agent, and a preparation method and application thereof

Abstract

The application discloses a kind of fluorine-containing benzimidazole derivative organic soldering flux protectant and its preparation method and application, it is related to printed circuit board (PCB) surface treatment technical field.The fluorine-containing benzimidazole derivative organic soldering flux protectant of the application uses fluorine-containing benzimidazole derivative as main film forming agent, benzimidazole benzene ring and on 2-benzyl benzene ring have F and / or Cl atom substitution, not only can improve the solubility of main film forming agent, and due to the polarity of carbon-fluorine bond is less, bond length is shorter, the van der waals force between molecules is stronger, the hydrophobicity and compactness of OSP film are enhanced, so as to improve the oxidation resistance and corrosion resistance of OSP film, high temperature resistance.And synergistic adjuvant, promote the self-assembly film forming speed of OSP film, further improve the low-temperature stability, oxidation resistance and corrosion resistance of OSP solution.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board (PCB) surface treatment technology, and more specifically, to a fluorinated benzimidazole derivative organic flux protectant, its preparation method, and its application. Background Technology

[0002] Surface treatment technology for printed circuit boards (PCBs) is the final and crucial step in the PCB packaging process, and its quality directly impacts the packaging quality and yield of the PCBs, thus it has always been highly valued. Among surface treatment technologies such as hot air leveling, chemical tin plating, chemical silver plating, chemical nickel / gold plating, and organic solderable preservatives (OSPs), organic solderable preservatives (OSPs) have been widely used due to their advantages, including high-temperature resistance, oxidation resistance, good solderability, low cost, simple operation, and ease of rework.

[0003] Organic solder protectants (OSPs) generally consist of a primary film-forming agent, low-molecular-weight organic acids, transition metal ions, water, and additives. They primarily form a hydrophobic and dense metal-organic protective film (OSP film) on the copper surface through coordination and complexation reactions between the primary film-forming agent and copper and copper ions, as well as van der Waals forces and hydrogen bonds between primary film-forming agent molecules. This prevents oxidation and corrosion of the copper surface (oxidation resistance), withstands repeated high-temperature reflow soldering without discoloration or decomposition (heat resistance), and is quickly dissolved by flux, maintaining good solderability of the copper surface (solderability). Therefore, the primary film-forming agent is the most fundamental influencing factor on the performance of the OSP film, playing a decisive role in its overall performance.

[0004] However, with the development of lead-free soldering and the increasing density and functionality of printed circuit boards, the number of soldering cycles will reach more than three, and the soldering temperature and time will be further increased and extended. This places higher demands on the oxidation resistance and heat resistance of OSP films. While mainstream film-forming agents with good performance in production applications, such as 2-halobenzylbenzimidazole, can barely withstand three reflow soldering cycles without discoloration, their OSP films need to reach a certain thickness (>0.2µm, preferably 0.3–0.35µm) to achieve good oxidation resistance and high-temperature resistance. However, if the film is too thick, it will age after multiple reflow soldering cycles, leading to decreased solderability. In addition, to accelerate film formation and obtain thicker OSP films, excessive film-forming accelerators such as n-heptanoic acid are usually added. This not only makes the OSP system unstable but may even cause precipitation, uneven film formation, loose film structure, and decreased hydrophobicity. This, in turn, leads to a decrease in the oxidation resistance and corrosion resistance of the OSP film, making it prone to electrochemical corrosion during storage and shortening the storage life of the PCB circuit board. Furthermore, to improve the heat resistance of OSP membranes, excessive zinc ions are often added to the solderability protectant. However, too high a zinc ion content increases wastewater treatment costs, causes water pollution, and is not environmentally friendly. Therefore, there is an urgent need to develop an organic solderability protectant with better heat resistance, hydrophobicity, oxidation resistance, and corrosion resistance while maintaining good solderability.

[0005] Existing technology discloses an organic solderable protectant using alkylamide benzimidazole compounds as the main film-forming substance. This is because the compound contains amide bonds, resulting in good solubility and some heat resistance. However, this alkylamide benzimidazole organic solderable protectant does not improve the hydrophobicity and oxidation resistance of printed circuit boards. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of existing organic solderable fluxes (OSPs) in terms of hydrophobicity and insufficient resistance to oxidation and corrosion, and to provide an organic solderable flux containing fluorinated benzimidazole derivatives.

[0007] Another object of the present invention is to provide the application of fluorinated benzimidazole derivative organic flux protectants in the oxidation resistance of copper or copper alloys.

[0008] The above-mentioned objective of this invention is achieved through the following technical solution:

[0009] A fluorinated benzimidazole derivative organic flux protectant, wherein the main film-forming agent is a fluorinated benzimidazole derivative, and its structural formula is as follows:

[0010] Where R 1 Selected from F or Cl, n represents R 1 The number of, n≥1, R2 Selected from any one of H, F, Cl or NH2, m represents R 2 The quantity, m≥1.

[0011] It should be noted that:

[0012] The main film-forming agent of the present invention is a fluorinated benzimidazole derivative, which has F and / or Cl atoms substituted on both the benzene ring and the 2-benzylbenzene ring. This not only improves the solubility of the main film-forming agent, but also enhances the hydrophobicity and compactness of the OSP film due to the low polarity and short bond length of the carbon-fluorine bond and the strong van der Waals forces between molecules. This improves the oxidation resistance, corrosion resistance and high temperature resistance of the OSP film.

[0013] In a specific implementation, preferably, n is 1 to 4 and m is 1 to 4.

[0014] In specific embodiments, the fluorinated benzimidazole derivatives of the present invention are preferably any one or more of the following fluorinated benzimidazole derivatives:

[0015] 5-Chloro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5-Chloro-2-(2-fluoro-4-chlorobenzyl)-1H-benzimidazole, 5-Chloro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5-fluoro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5-fluoro-2-(2-fluoro-4-chlorobenzyl)-1H-benzimidazole Imidazole, 5-fluoro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(2-fluoro-4-chlorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2- (2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(2-fluoro-4-chlorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(3-chloro-5-fluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(3-fluoro-5-chlorobenzyl) 5,6-difluoro-2-(3,5-difluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(3-chloro-5-fluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(3-fluoro-5-chlorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(3,5-difluorobenzyl)-1H-benzimidazole.

[0016] Preferably, the main film-forming agent is 5-chloro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, or 5,6-difluoro-2-(3,5-difluorobenzyl)-1H-benzimidazole.

[0017] In specific embodiments, the fluorinated benzimidazole derivative organic flux protectant of the present invention may have other components added according to actual needs. Preferably, the fluorinated benzimidazole derivative organic flux protectant of the present invention includes the following components:

[0018] Main film-forming agent 0.8–3.5 g / L, organic solvent 150–350 g / L, copper ions 0.05–1.0 g / L, additives 0.1–4.0 g / L.

[0019] The adjuvant contains phenolic hydroxyl, hydroxyl or carboxyl groups.

[0020] The fluorinated benzimidazole derivative organic flux protectant of the present invention also incorporates additives with synergistic effects. The additive molecules contain phenolic hydroxyl or hydroxyl, carboxyl and other groups, which enhance hydrogen bonding to make the OSP solution more stable. Moreover, they can synergistically adsorb on the metal surface with the main film-forming agent, which can increase the thickness of the adsorption film, accelerate the adsorption rate, and promote the self-assembly of the OSP film. At the same time, since the additive has good antioxidant properties, it further improves the oxidation resistance and corrosion resistance of the OSP film.

[0021] Preferably, the additive is 0.5–2.0 g / L.

[0022] Preferably, the adjuvant is one or more of gallic acid, 3,4-dihydroxybenzoic acid, and fulvic acid.

[0023] To further control the film-forming effect and solution stability, preferably, the pH value of the fluorinated benzimidazole derivative organic flux of the present invention is 2.5 to 4.0.

[0024] Preferably, the organic solvent is formic acid and acetic acid, wherein the ratio of formic acid to acetic acid is (0.1-1):1.

[0025] More preferably, the ratio of formic acid to acetic acid is 1:4 to 1:9.

[0026] Adding an appropriate amount of formic acid to an organic solvent can promote the growth of OSP membranes and provide a sufficiently thick OSP membrane.

[0027] In specific embodiments, the copper ions mentioned in this invention can be one or more of copper chloride, copper formate, and copper acetate.

[0028] In a specific embodiment, the pH adjuster described in this invention can be ammonia, etc.

[0029] The fluorinated benzimidazole derivative organic flux of the present invention does not contain zinc salt.

[0030] The fluorinated benzimidazole derivative organic flux of this invention does not require the addition of zinc salts to improve heat resistance, eliminates the pollution of water bodies by zinc ions, saves water treatment costs, and is more environmentally friendly.

[0031] The fluorinated benzimidazole derivative organic flux protectant of the present invention can be prepared according to conventional methods in the art, for example, its preparation method includes the following steps:

[0032] Dissolve the main film-forming agent in an organic solvent, then add the auxiliary agent and stir until homogeneous to obtain solution A;

[0033] Then dissolve the copper ions in water to obtain solution B;

[0034] While stirring, pour solution A into solution B, continue stirring until homogeneous, and finally adjust the pH to obtain a fluorinated benzimidazole derivative organic flux protectant.

[0035] The present invention also specifically protects the application of a fluorinated benzimidazole derivative organic flux protective agent in the oxidation resistance of copper or copper alloys.

[0036] The fluorinated benzimidazole derivative organic soldering flux of this invention can be used in the printed circuit board industry, for example, in the surface treatment of printed circuit boards (PCBs). The fluorinated benzimidazole derivative organic soldering flux of this invention exhibits excellent solderability. It shows minimal discoloration after five reflow soldering cycles, and after three reflow soldering cycles, the solder remains bright and full, forming a uniform film on the surface of the printed circuit board.

[0037] However, without limitation, the fluorinated benzimidazole derivative organic fluxing agent disclosed in this invention can also be used as an antioxidant in the anti-oxidation of copper or copper alloys, and therefore can be used in other industries.

[0038] The specific application method of the fluorinated benzimidazole derivative organic flux protectant of the present invention can be found as follows:

[0039] Micro-etch the PCB board or copper plate in the micro-etching solution for 30-60 seconds, rinse it twice with deionized water and blow it dry, then immerse it in an organic solder resist agent (OSP) heated to 40-45℃ for 40-120 seconds, and then rinse and dry it.

[0040] The application of the fluorinated benzimidazole derivative organic flux protectant of the present invention does not require pre-dip treatment, thus saving production costs.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] The fluorinated benzimidazole derivative organic flux protectant of this invention uses a fluorinated benzimidazole derivative as the main film-forming agent. Both the benzene ring and the 2-benzylbenzene ring of the benzimidazole are substituted with F and / or Cl atoms, which not only improves the solubility of the main film-forming agent, but also enhances the hydrophobicity and compactness of the OSP film due to the low polarity and short bond length of the carbon-fluorine bond, resulting in stronger van der Waals forces between molecules. This improves the oxidation resistance, corrosion resistance, and high-temperature resistance of the OSP film. Furthermore, the synergistic additives promote the self-assembly rate of the OSP film, further improving the low-temperature stability, oxidation resistance, and corrosion resistance of the OSP solution.

[0043] The fluorinated benzimidazole derivative organic flux of the present invention can withstand five reflow soldering cycles without changing color. Electrochemical experiments show that its corrosion inhibition rate reaches more than 98%, and salt spray experiments show that it can withstand 60 hours of corrosion in the fume without corrosion, and has excellent solderability. Attached Figure Description

[0044] Figure 1 The images show photographs of the OSP film copper sheets from Examples 1 to 12 after 0 to 7 reflow soldering cycles.

[0045] Figure 2 These are photographs of Comparative Examples 1-6 after 0-3 reflow soldering cycles.

[0046] Figure 3 The images show the effects of uniform and non-uniform film formation.

[0047] Figure 4 The images show the effects of good and poor soldering. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0049] Example 1

[0050] A fluorinated benzimidazole derivative organic soldering flux protectant, comprising the following components:

[0051] 6-Chloro-2-(2-Chloro-4-fluorobenzyl)-1H-benzimidazole 2.0 g / L, organic solvent 250 g / L, of which formic acid:acetic acid ratio is 1:4, copper chloride 1.0 g / L, gallic acid 2.0 g / L, and water balance.

[0052] The pH value of the fluorinated benzimidazole derivative organic flux protectant is 3.0.

[0053] The preparation method of the fluorinated benzimidazole derivative organic flux protectant in Example 1 above is as follows: 5-chloro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole is dissolved in organic solvents formic acid and acetic acid, gallic acid is added, and the mixture is stirred until homogeneous, which is A; then copper chloride is dissolved in water, which is B; while stirring, A is slowly poured into B, and the mixture is stirred until homogeneous. Finally, the pH value is adjusted to 3.0 with ammonia water.

[0054] The application method of the fluorinated benzimidazole derivative organic flux protectant in Example 1 above is as follows: the copper plate is micro-etched in the micro-etching solution for 60 seconds, washed and dried with deionized water twice, and then immersed in organic flux protectant (OSP) heated to 45°C for 60 seconds. After washing and drying, the OSP film can be obtained.

[0055] Example 2

[0056] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0057] The main film-forming agent, 5-chloro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, is 1.0 g / L.

[0058] Example 3

[0059] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0060] The main film-forming agent, 5-chloro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, is 3.0 g / L.

[0061] Example 4

[0062] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0063] The pH value of the fluorinated benzimidazole derivative organic flux protectant is 2.8.

[0064] Example 5

[0065] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0066] The pH value of the fluorinated benzimidazole derivative organic flux protectant is 3.6.

[0067] Example 6

[0068] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0069] The adjuvant gallic acid is 0.1 g / L.

[0070] Example 7

[0071] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0072] The adjuvant gallic acid concentration is 4.0 g / L.

[0073] Example 8

[0074] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0075] The ratio of organic solvent formic acid to acetic acid is 0:1.

[0076] Example 9

[0077] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0078] The ratio of organic solvent formic acid to acetic acid is 1:1.

[0079] Example 10

[0080] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that:

[0081] The auxiliary agent is 3,4-dihydroxybenzoic acid.

[0082] Example 11

[0083] An organic flux protectant containing a fluorinated benzimidazole derivative is basically the same as that in Example 1, except that the main film-forming agent is 5-chloro-6-fluoro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole.

[0084] Example 12

[0085] A fluorinated benzimidazole derivative organic flux protectant, basically the same as in Example 1, except that: the main film-forming agent is 5,6-difluoro-2-(3,5-difluorobenzyl)-1H-benzimidazole.

[0086] Comparative Example 1

[0087] An organic flux protectant, which is basically the same as that in Example 1, except that no additives are added.

[0088] Comparative Example 2

[0089] An organic soldering flux protective agent, comprising the following components:

[0090] Benzylbenzimidazole 2.0 g / L, organic solvent 250 g / L, wherein formic acid:acetic acid ratio is 1:4, and copper chloride.

[0091] 1.0 g / L, gallic acid 2.0 g / L, water balance.

[0092] The pH value of the organic flux protectant is 3.0.

[0093] The preparation method of the organic flux protectant in Comparative Example 1 is as follows: Benzylbenzimidazole is dissolved in organic solvents formic acid and acetic acid, gallic acid is added, and the mixture is stirred until homogeneous, resulting in A; copper chloride is then dissolved in water, resulting in B; while stirring, A is slowly poured into B, and the mixture is stirred until homogeneous. Finally, the pH value is adjusted to 3.0 with ammonia water.

[0094] The application method of the organic flux protectant in Comparative Example 1 is as follows: the copper plate is micro-etched in the micro-etching solution for 60 seconds, washed and dried with deionized water twice, and then immersed in the organic flux protectant (OSP) heated to 45°C for 60 seconds. After washing and drying, the OSP film can be obtained.

[0095] Comparative Example 3

[0096] An organic flux protectant is basically the same as that in Example 1, except that the main film-forming agent is 2-(2,4-difluoro)benzylbenzimidazole.

[0097] Comparative Example 4

[0098] An organic flux protectant is basically the same as that in Example 1, except that the main film-forming agent is 2-(2-chloro-4-fluoro)benzylbenzimidazole.

[0099] Comparative Example 5

[0100] An organic flux protectant is basically the same as that in Example 1, except that the main film-forming agent is 2-(2-chloro-4-fluoro)benzylbenzimidazole.

[0101] Comparative Example 6

[0102] An organic flux protectant is basically the same as that in Example 1, except that the main film-forming agent is 2-(4-fluoro)benzylbenzimidazole.

[0103] Result detection

[0104] Performance evaluation of the OSP membranes of the above embodiments and comparative examples.

[0105] The specific performance evaluation methods are as follows:

[0106] 1. OSP solution stability test method: Under room temperature conditions, after the OSP solution has been left for one week, observe whether the OSP solution is clear or turbid, and observe whether there is any solid precipitation. If there is precipitation or the solution becomes more turbid, it indicates instability. If the solution state remains unchanged, it is stable.

[0107] 2. OSP film uniformity test method: Cut copper sheets coated with OSP films into 1cm x 1cm samples, and then observe the film uniformity using focused ion beam scanning electron microscopy (FIB-SEM). The effects of uniform and non-uniform film formation are shown in the figure. Figure 3 As shown.

[0108] 3. OSP film thickness measurement method:

[0109] Place a 4*4cm copper-clad laminate in 50ml of 5% hydrochloric acid and shake for 3-5 minutes to dissolve the film completely. Measure the absorbance at 278nm. Then, calculate the OSP film thickness using the film thickness calculation formula δ=0.41A established based on the film thickness measured by FIB-SEM and the corresponding absorbance.

[0110] 4. Contact angle measurement method:

[0111] The contact angle of the OSP film copper sheet was measured and the film formation was visually inspected during water washing.

[0112] 5. Method for determining heat resistance:

[0113] The temperature change curves for the reflow soldering process are as follows: 170–193℃, 1 min; 193–242℃, 1 min; 242–277℃, 2 min; 277–239℃, 1 min; 239–225℃, 1 min.

[0114] 6. Salt spray tolerance test method:

[0115] According to the standard GB / T10125-1997 Neutral Smoke Test Method, the OSP film copper plate was placed in a salt spray machine and continuously sprayed with 3.5% sodium chloride solution salt spray at 35℃, and the corrosion of the copper plate was observed.

[0116] 7. Method for determining electrochemical corrosion inhibition rate:

[0117] (1) A three-electrode system was adopted, with an OSP copper plate as the working electrode (WE), a platinum electrode as the auxiliary electrode (CE), and a saturated calomel electrode (SCE) as the reference electrode (RE). The electrolyte solution was a 3.5 wt% NaCl solution. The corrosion current was determined by measuring the polarization curve, and then the corrosion inhibition rate was calculated.

[0118] 8. Solderability testing method:

[0119] Heat the solder pot to 260℃. Immerse the OSP film copper foil, which has undergone three reflow soldering cycles, in flux for 10 seconds. After removing it and letting it rest for about 1 minute, immerse it in molten FX-306 lead-free solder for 10 seconds. Check the soldering condition of the copper surface. Good soldering is characterized by bright, full solder coverage with no exposed copper; uneven soldering with exposed copper is considered poor soldering. The effects of good and poor soldering are shown below. Figure 4 As shown.

[0120] The specific results are shown in Table 1 below:

[0121] Table 1

[0122]

[0123] in, Figure 1 The images show photographs of the OSP film copper sheets from Examples 1 to 12 after 0 to 7 reflow soldering cycles.

[0124] Figure 2 These are photographs of Comparative Examples 1-6 after 0-3 reflow soldering cycles.

[0125] From Table 1 and Figure 1 It can be seen that the OSP film formed by the application of the fluorinated benzimidazole derivative organic flux protectant of the present invention has excellent solderability. After 5 reflow soldering cycles, the solder is still bright and full, and can withstand more than 3 reflow soldering cycles without changing color.

[0126] As can be seen from Table 1, the fluorinated benzimidazole derivative organic flux of the present invention has good water resistance, with a water contact angle of over 76°, thereby improving the heat resistance, oxidation resistance and corrosion resistance of the OSP film. Electrochemical experiments show that its corrosion inhibition rate reaches over 98%, and salt spray experiments also show that it can withstand 60 hours of salt spray without corrosion.

[0127] As can be seen from the comparative examples, other main film-forming agents outside the scope of protection of this invention cannot achieve the technical effects of this invention. The hydrophobicity and corrosion resistance are deteriorated, and the weldability is poor.

[0128] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A fluorinated benzimidazole derivative organic flux protective agent, characterized in that, It consists of the following components: Main film-forming agent 0.8~3.5g / L, organic solvent 150~350g / L, copper ions 0.05~1.0g / L, additives 0.1~4.0g / L; The adjuvant is one or more of gallic acid, 3,4-dihydroxybenzoic acid, or fulvic acid; The organic solvent is formic acid and acetic acid, wherein the mass ratio of formic acid to acetic acid is (0.1~1):1; The main film-forming agent is a fluorinated benzimidazole derivative, and its structural formula is as follows: , where R 1 Selected from F or Cl, n represents R 1 The number of, n≥1, R 2 Selected from any one of H, F, Cl, or NH2, m represents R 2 The quantity, m≥1.

2. The fluorinated benzimidazole derivative organic flux protectant as described in claim 1, characterized in that, n is 1~4, m is 1~4.

3. The fluorinated benzimidazole derivative organic flux protectant as described in claim 1, characterized in that, The main film-forming agent is 5-chloro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5-chloro-2-(2-fluoro-4-chlorobenzyl)-1H-benzimidazole, 5-chloro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5-fluoro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5-fluoro-2-(2-fluoro-4-chloro ... H-benzimidazole, 5-fluoro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(2-fluoro-4-chlorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2- (2-chloro-4-fluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(2-fluoro-4-chlorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(2,4-difluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(3-chloro-5-fluorobenzyl)-1H-benzimidazole, 5-chloro-6-fluoro-2-(3-fluoro-5-chlorobenzyl)- One or more of 1H-benzimidazole, 5-chloro-6-fluoro-2-(3,5-difluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(3-chloro-5-fluorobenzyl)-1H-benzimidazole, 5,6-difluoro-2-(3-fluoro-5-chlorobenzyl)-1H-benzimidazole, and 5,6-difluoro-2-(3,5-difluorobenzyl)-1H-benzimidazole.

4. The fluorinated benzimidazole derivative organic flux protectant as described in claim 1, characterized in that, The additive is 0.5~2.0 g / L.

5. The fluorinated benzimidazole derivative organic flux protectant as described in claim 1, characterized in that, The pH value of the fluorinated benzimidazole derivative organic flux protective agent is 2.5~4.

0.

6. A method for preparing the fluorinated benzimidazole derivative organic flux protective agent according to any one of claims 1 to 5, characterized in that, Includes the following steps: Dissolve the main film-forming agent in an organic solvent, then add the auxiliary agent and stir until homogeneous to obtain solution A; Then dissolve the copper ions in water to obtain solution B; While stirring, pour solution A into solution B, continue stirring until homogeneous, and finally adjust the pH to obtain a fluorinated benzimidazole derivative organic flux protectant.

7. The application of the fluorinated benzimidazole derivative organic flux protectant according to any one of claims 1 to 5 in the oxidation resistance of copper or copper alloys.

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