PCB ink-jet printing pretreatment agent, preparation method thereof and PCB ink-jet printing method

Abstract

The invention discloses a PCB ink-jet printing pretreatment agent, a preparation method thereof and a PCB ink-jet printing method, and relates to the technical field of printed circuit board production. The PCB ink-jet printing pretreatment agent is prepared from the following components in mass concentration: 0.1 to 0.5 percent of an anti-diffusion agent, 0.1 to 0.5 percent of a wetting agent, 0.2 to 1.0 percent of a homogenizing agent, 0.5 to 2.5 percent of a dispersing agent, 0.1 to 3.0 percent of a cosolvent and the balance of water. The PCB ink-jet printing pretreatment agent can be used in a surface treatment procedure of a fine PCB pattern ink-jet printing process, a uniform organic layer can be formed on a PCB copper surface and a substrate surface, and the organic layer can effectively reduce surface tension of the copper surface and the substrate surface, prevent diffusion of jet printing ink on the PCB surface, promote uniform arrangement of the ink and improve the printing quality of the PCB. Stable and neat linear ink can be formed, and the product yield of a fine line ink-jet printing process is improved.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit board production, and in particular to a PCB inkjet printing pre-treatment agent and a preparation method thereof, and a PCB inkjet printing method. Background Art

[0002] Since the beginning of the 21st century, with the rise of emerging technologies such as smartphones and artificial intelligence, printed circuit boards (PCBs) have entered a new stage of miniaturization and thinness. From a technical perspective, PCB circuit design has been continuously refined, and line width and line spacing have been continuously reduced. Some companies have successfully achieved the production process of 30μm fine lines, improving the overall performance of the circuit. From a market perspective, the demand for smartphones, automotive electronics, medical equipment, industrial control and other fields continues to grow, and the demand for PCB fine lines has increased significantly. Line refinement is one of the directions for future technological development.

[0003] PCB inkjet printing technology is based on the pre-designed PCB graphic data. The control system accurately controls the movement of the print head on the PCB and the timing and amount of ink spraying, so that the ink is deposited on the substrate according to the predetermined pattern to form conductive circuits, solder mask layers, character logos and other graphics required for various PCBs. In addition, in the solder mask process, the printing equipment can accurately print the ink on the PCB surface, covering the area that does not need to be welded, preventing problems such as short circuits during welding, and improving welding quality and PCB reliability. Compared with traditional PCB production processes such as photolithography and screen printing, inkjet printing technology does not require complex plate making, development, etching and other processes. The ink can be directly sprayed onto the substrate to form the required graphics, greatly shortening the production cycle and improving production efficiency. In addition, PCB inkjet printing technology can achieve micron-level printing accuracy, positioning accuracy of up to ±35μm, repeatability accuracy of up to ±5μm, and high printing resolution, which can meet the production needs of high-density PCB circuits and fine graphics. With the continuous advancement of technology, inkjet printing technology will develop in the direction of higher resolution and higher precision to meet the future needs of PCBs to develop towards higher density and smaller size, and has good development prospects.

[0004] At present, research on inkjet printing ink diffusion prevention agents has made good research progress. Patent CN118290987A discloses a PCB inkjet printing diffusion prevention agent, which contains components such as oleophobic agent 1, oleophobic agent 2, wetting agent, stabilizer, and cosolvent, and can form an organic layer on the copper surface and substrate surface of the circuit board to strengthen the bonding force between the copper surface and the substrate surface and the ink, wherein the contact angle between the copper surface and the solder resist ink is greater than 90°, and the contact angle between the substrate surface and the solder resist ink is greater than 80°, which can effectively slow down the diffusion speed of the inkjet printing on the copper surface and the substrate surface, and prevent the ink from diffusing around the PCB surface before curing.

[0005] Inkjet printing technology is more mature in the printing of PCB character logos, but less used in the printing of PCB circuits and solder mask layers. The existing technology uses a "super-roughening + anti-diffusion agent" treatment process, which can effectively solve the diffusion and adhesion problems of inkjet printing inks, and help promote the industrial application of inkjet printing technology. At present, many PCB companies are constantly conducting inkjet printing tests. Although they have not yet been officially put into production, they have achieved good results. The existing technology can meet the printing of ordinary PCBs, but when printing fine circuits, the ink will spread, and problems such as distorted circuits, incomplete printing, and overlapping circuits will occur, resulting in an increase in the defective rate of products in this process, increasing rework costs or causing scrap. Therefore, an inkjet printing pretreatment agent is needed to meet the production of fine circuit inkjet printing. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is achieved through the following technical solutions.

[0007] Provided is a PCB inkjet printing pretreatment agent, which is composed of the following components in mass concentration: Anti-diffusion agent 0.1-0.5%, Wetting agent 0.1-0.5%, Leveling agent 0.2-1.0%, Dispersant 0.5-2.5%, Solvent 0.1-3.0%, The balance is water; The anti-diffusion agent is a fluorobenzenethiophenol compound, the wetting agent is a polyethylene glycol acrylate compound, the homogenizing agent is a carboxylic acid phenyl ester compound, the dispersant is a carboxybenzocrown ether compound, and the cosolvent is a pinacol ester compound.

[0008] Preferably, the diffusion prevention agent is selected from at least one of 2,4-difluorothiophenol (CAS No.: 1996-44-7), 3,4-difluorothiophenol (CAS No.: 60811-24-7), and 3,5-difluorothiophenol (CAS No.: 99389-26-1).

[0009] Preferably, the wetting agent is selected from at least one of methoxy polyethylene glycol (350) acrylate (CAS No.: 32171-39-4), polyethylene glycol (400) methacrylate (CAS No.: 9051-31-4), and polyethylene glycol (400) monoacrylate (CAS No.: 9051-31-4); "350" and "400" in brackets refer to the average molecular weight of the polyethylene glycol segment.

[0010] Preferably, the homogenizing agent is selected from at least one of diphenyl phenylphosphonate (CAS No.: 3049-24-9), diphenyl malonate (CAS No.: 1969-44-4), and benzyl glycolate (CAS No.: 30379-58-9).

[0011] Preferably, the dispersant is selected from at least one of 4'-carboxybenzo-15-crown-5-ether (CAS No.: 56683-55-7) and 4'-carboxybenzo-18-crown-6-ether (CAS No.: 60835-75-8).

[0012] Preferably, the cosolvent is selected from at least one of 6-quinolineboronic acid pinacol ester (CAS No.: 406463-06-7) and 4-benzylphenylboronic acid pinacol ester (CAS No.: 911708-01-5).

[0013] The preparation method of the above-mentioned PCB inkjet printing pretreatment agent is to place an anti-diffusion agent, a wetting agent, a homogenizer, a dispersant, a cosolvent and water in a reaction container, mix them evenly at 55-65° C., and obtain the PCB inkjet printing pretreatment agent after cooling to room temperature.

[0014] Preferably, the preparation method of the above-mentioned PCB inkjet printing pretreatment agent is to place an anti-diffusion agent, a wetting agent, a homogenizer, a dispersant, a cosolvent and water in a reaction container, mix them at 55-65°C for 20-60 minutes, and cool them to room temperature to obtain the PCB inkjet printing pretreatment agent.

[0015] The present invention also provides a PCB inkjet printing method, comprising the following steps: Surface treatment: Soak the PCB in the above-mentioned PCB inkjet printing pre-treatment agent for 1.5-3 minutes; Inkjet printing: Inkjet and cure the surface treated PCB.

[0016] Furthermore, before the surface treatment, an ultra-roughening treatment is also included: ultra-roughening etching is performed on the PCB.

[0017] Preferably, the ultra-roughening etching amount is 0.8-1.0 μm.

[0018] The PCB inkjet printing pretreatment agent of the present invention can be used in the surface treatment process of the fine PCB graphic inkjet printing process. The pretreatment agent contains effective ingredients such as an anti-diffusion agent, a wetting agent, a leveler, a dispersant, a cosolvent, etc., and can form a uniform organic layer on the copper surface of the PCB and the surface of the substrate. The organic layer can not only effectively reduce the surface tension of the copper surface and the surface of the substrate, prevent the ink from spreading on the PCB surface, but also promote the uniform arrangement of the ink, which is conducive to forming a stable and neat linear ink, and improves the product yield of the fine line inkjet printing process.

[0019] In the PCB inkjet printing pretreatment agent of the present invention, the anti-diffusion agent mainly acts on the surface of the PCB board, reduces the surface tension of the copper surface and the substrate surface, and achieves the effect of ink diffusion prevention. The wetting agent is a type of surfactant containing both hydrophilic and lipophilic functional groups, which can reduce the surface tension of the PCB surface and enable the effective ingredients in the pretreatment agent to fully contact the PCB surface. On the one hand, the leveling agent can accelerate the penetration and diffusion of the effective ingredients in the pretreatment agent, and on the other hand, it has a "lubricating" effect, which enhances the fluidity of the effective ingredients in the pretreatment agent and improves the uniformity of wetting. The dispersant can improve the dispersibility, fluidity and uniformity of each component in the pretreatment agent, so that the organic layer formed by the pretreatment agent on the PCB board surface is more evenly distributed. The cosolvent is used to dissolve the components that are insoluble in water in the components to form a relatively stable solution system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0021] Figure 1 The copper surface ink circuit of Example 1; Figure 2 The ink circuit on the substrate surface of Example 1; Figure 3 The copper surface ink circuit of Comparative Example 1; Figure 4 This is the ink circuit on the substrate surface of Comparative Example 1. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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.

[0023] Example 1 According to the following formula (mass concentration), weigh the anti-diffusion agent, wetting agent, homogenizing agent, dispersant, co-solvent and the balance water in turn and add them into the reaction kettle, stir and mix at 60°C for 30 minutes and then cool to room temperature to obtain the PCB inkjet printing pretreatment agent of this embodiment.

[0024] The content of the anti-diffusion agent is 0.1%, specifically: 2,4-difluorobenzenethiol; The wetting agent content is 0.3%, specifically: methoxy polyethylene glycol (350) acrylate; The leveling agent content is 0.5%, specifically diphenyl phenylphosphonate; The dispersant content is 1.5%, specifically 4'-carboxybenzo-15-crown-5-ether; The content of the cosolvent is 1.5%, specifically 6-quinolineboronic acid pinacol ester; The balance is water.

[0025] Example 2 According to the following formula (mass concentration), weigh the anti-diffusion agent, wetting agent, homogenizing agent, dispersant, co-solvent and the balance water in turn and add them into the reaction kettle, stir and mix at 60°C for 30 minutes and then cool to room temperature to obtain the PCB inkjet printing pretreatment agent of this embodiment.

[0026] The content of the anti-diffusion agent is 0.1%, specifically: 3,4-difluorobenzenethiol; The wetting agent content is 0.3%, specifically: polyethylene glycol (400) methacrylate; The leveling agent content is 0.5%, specifically diphenyl malonate; The dispersant content is 1.5%, specifically 4'-carboxybenzo-18-crown-6-ether; The cosolvent content is 1.5%, specifically 4-benzylphenylboronic acid pinacol ester; The balance is water.

[0027] Example 3 According to the following formula (mass concentration), weigh the anti-diffusion agent, wetting agent, homogenizing agent, dispersant, co-solvent and the balance water in turn and add them into the reaction kettle, stir and mix at 60°C for 30 minutes and then cool to room temperature to obtain the PCB inkjet printing pretreatment agent of this embodiment.

[0028] The content of the anti-diffusion agent is 0.1%, specifically: 3,5-difluorobenzenethiol; The wetting agent content is 0.3%, specifically: polyethylene glycol (400) monoacrylate; The leveling agent content is 0.5%, specifically benzyl glycolate; The dispersant content is 1.5%, specifically 4'-carboxybenzo-15-crown-5-ether; The cosolvent content is 1.5%, specifically 4-benzylphenylboronic acid pinacol ester; The balance is water.

[0029] Example 4 According to the following formula (mass concentration), weigh the anti-diffusion agent, wetting agent, homogenizing agent, dispersant, co-solvent and the balance water in turn and add them into the reaction kettle, stir and mix at 60°C for 30 minutes and then cool to room temperature to obtain the PCB inkjet printing pretreatment agent of this embodiment.

[0030] The content of the anti-diffusion agent is 0.1%, specifically: 2,4-difluorobenzenethiol; The wetting agent content is 0.3%, specifically: polyethylene glycol (400) methacrylate; The leveling agent content is 0.5%, specifically benzyl glycolate; The dispersant content is 1.5%, specifically 4'-carboxybenzo-18-crown-6-ether; The cosolvent content is 1.5%, specifically 4-benzylphenylboronic acid pinacol ester; The balance is water.

[0031] Example 5 According to the following formula (mass concentration), weigh the anti-diffusion agent, wetting agent, homogenizing agent, dispersant, co-solvent and the balance water in turn and add them into the reaction kettle, stir and mix at 60°C for 30 minutes and then cool to room temperature to obtain the PCB inkjet printing pretreatment agent of this embodiment.

[0032] The content of the anti-diffusion agent is 0.3%, specifically: 3,5-difluorobenzenethiol; The wetting agent content is 0.3%, specifically: methoxy polyethylene glycol (350) acrylate; The leveling agent content is 0.5%, specifically diphenyl phenylphosphonate; The dispersant content is 1.5%, specifically diphenyl malonate; The content of the cosolvent is 1.5%, specifically 6-quinolineboronic acid pinacol ester; The balance is water.

[0033] Example 6 According to the following formula (mass concentration), weigh the anti-diffusion agent, wetting agent, homogenizing agent, dispersant, co-solvent and the remaining water in turn and add them into the reaction kettle, stir and mix at 55°C for 60 minutes and then cool to room temperature to obtain the PCB inkjet printing pretreatment agent of this embodiment.

[0034] The content of the anti-diffusion agent is 0.1%, specifically: 2,4-difluorobenzenethiol; The wetting agent content is 0.1%, specifically: methoxy polyethylene glycol (350) acrylate; The leveling agent content is 0.2%, specifically diphenyl phenylphosphonate; The dispersant content is 0.5%, specifically 4'-carboxybenzo-15-crown-5-ether; The content of the cosolvent is 0.1%, specifically 6-quinolineboronic acid pinacol ester; The balance is water.

[0035] Example 7 According to the following formula (mass concentration), weigh the anti-diffusion agent, wetting agent, homogenizer, dispersant, co-solvent and the remaining water in turn and add them into the reaction kettle, stir and mix at 65°C for 25 minutes and then cool to room temperature to obtain the PCB inkjet printing pretreatment agent of this embodiment.

[0036] The content of the anti-diffusion agent is 0.5%, specifically: 2,4-difluorobenzenethiol; The wetting agent content is 0.5%, specifically: methoxy polyethylene glycol (350) acrylate; The leveling agent content is 1.0%, specifically diphenyl phenylphosphonate; The dispersant content is 2.5%, specifically 4'-carboxybenzo-15-crown-5-ether; The cosolvent content is 3%, specifically 6-quinolineboronic acid pinacol ester; The balance is water.

[0037] In the process of exploring the effects of PCB inkjet printing pretreatment agents of different component systems, the present invention also prepared the following comparative examples of PCB inkjet printing pretreatment agents.

[0038] Comparative Example 1 The PCB inkjet printing pre-treatment agent of Comparative Example 1 is different from that of Example 1 only in that the component does not contain an anti-diffusion agent.

[0039] Comparative Example 2 The PCB inkjet printing pre-treatment agent of Comparative Example 2 is different from that of Example 1 only in that the component does not contain a wetting agent.

[0040] Comparative Example 3 The PCB inkjet printing pre-treatment agent of Comparative Example 3 is different from that of Example 1 only in that the component does not contain a leveling agent.

[0041] Comparative Example 4 The PCB inkjet printing pre-treatment agent of Comparative Example 4 is different from that of Example 1 only in that the component does not contain a dispersant.

[0042] Comparative Example 5 The PCB inkjet printing pre-treatment agent of Comparative Example 5 is different from that of Example 1 only in that the component does not contain a co-solvent.

[0043] Comparative Example 6 The PCB inkjet printing pretreatment agent of Comparative Example 6 is different from that of Example 1 only in that the concentration of the anti-diffusion agent in the component is 1.0%.

[0044] Comparative Example 7 The PCB inkjet printing pre-treatment agent of Comparative Example 7 is different from that of Example 1 only in that the concentration of the wetting agent in the component is 1.0%.

[0045] Comparative Example 8 The PCB inkjet printing pretreatment agent of Comparative Example 8 is different from that of Example 1 only in that the concentration of the leveling agent in the component is 2.0%.

[0046] Comparative Example 9 The PCB inkjet printing pretreatment agent of Comparative Example 9 is different from that of Example 1 only in that the concentration of the dispersant in the component is 5.0%.

[0047] Comparative Example 10 The PCB inkjet printing pretreatment agent of Comparative Example 10 is different from that of Example 1 only in that the concentration of the co-solvent in the component is 6.0%.

[0048] Comparative Example 11 The PCB inkjet printing pretreatment agent of Comparative Example 11 is different from that of Example 1 only in that the anti-diffusion agent component 2,4-difluorothiophenol is replaced by sodium thiophenol (CAS No.: 930-69-8).

[0049] Comparative Example 12 The PCB inkjet printing pretreatment agent of Comparative Example 12 is different from that of Example 1 only in that the wetting agent component methoxy polyethylene glycol (350) acrylate is replaced by triethylene glycol dimethacrylate (CAS No.: 109-16-0).

[0050] Comparative Example 13 The PCB inkjet printing pretreatment agent of Comparative Example 13 is different from that of Example 1 only in that the leveling agent component diphenyl phenylphosphonate is replaced by methylpyrrole-2-carboxylate (CAS No.: 1193-62-0).

[0051] Comparative Example 14 The PCB inkjet printing pretreatment agent of Comparative Example 14 is different from that of Example 1 only in that the dispersant component 4'-carboxybenzo-15-crown-5-ether is replaced by 15-crown-5 (CAS No.: 33100-27-5).

[0052] Comparative Example 15 Comparative Example 15 uses the PCB inkjet printing anti-diffusion agent of the prior art (Chinese patent application CN118290987A), and specifically, its ingredients include: The content of oleophobic agent 1 is 0.1%, specifically: dicyclohexane-18-crown ether-6; The content of oleophobic agent 2 is 0.3%, specifically: 5-amino-2-naphthalenesulfonic acid; The wetting agent content is 0.5%, specifically 3-sulfopropyltetradecyl dimethyl betaine; The stabilizer content is 1.5%, specifically methyl 3,4-diaminobenzoate; The co-solvent content is 1.5%, specifically 1-amino-4-piperidinol; The balance is water.

[0053] The PCB inkjet printing pretreatment agent or PCB inkjet printing anti-diffusion agent of the above-mentioned Examples 1-7 and Comparative Examples 1-15 are respectively used for the production of fine PCB graphic inkjet printing, and the process includes the following steps: S1 water washing; S2 degreasing; S3 water washing; S4 super-roughening; S5 water washing; S6 hydrochloric acid washing; S7 water washing; S8 surface treatment; S9 water washing; S10 drying; S11 inkjet printing.

[0054] The specific process is as follows: The S1 washing section is used to wash the printed circuit board to be inkjet printed with tap water. The process parameters of the washing section are: this section is immersion type, the washing temperature is 25±1°C, the washing section length is 1.0m, and the line speed is 2.0±0.2m / min; The S2 degreasing section is used to clean the printed circuit board that has passed through the S1 water washing section to remove surface impurities. The process parameters of the degreasing section are as follows: this section is spray-type, the sulfuric acid concentration is 0.5%, and the remainder is tap water; the degreasing temperature is 25±1°C, the degreasing section length is 2.0m; the line speed is 2.0±0.2m / min, and the pressure is 1.5±0.5kg / cm 2 ; The S3 water washing section is used to wash the printed circuit board that has passed through the S2 oil removal section with tap water. The process parameters of the water washing section are: this section is immersion type, the water washing temperature is 25±1°C, the water washing section length is 1.0m, and the line speed is 2.0±0.2m / min; The S4 super-roughening section is used to etch the printed circuit board that has passed through the S3 water washing section. The process parameters of the super-roughening section are as follows: this section is a spray type, the super-roughening solution in the cylinder is the super-roughening liquid model BTH-2085B of Shenzhen Banming Technology Co., Ltd., the super-roughening liquid is used as the original liquid, the temperature in the cylinder is 25±5℃, the super-roughening section length is 3.0 m; the line speed is 3.0±0.2 m / min, and the spray pressure is 1.5±0.5 kg / cm 2 ;Ultra-roughening etching amount is 0.8-1.0μm; The S5 washing section is used to wash the printed circuit board after the S4 super-roughening section with tap water. The process parameters of the washing section are: this section is immersion type, the washing temperature is 25±1°C, the washing section length is 1.0m, and the line speed is 2.0±0.2m / min; The S6 hydrochloric acid washing section is used to wash the printed circuit board after passing through the S5 water washing section with hydrochloric acid. The process parameters of the hydrochloric acid washing section are as follows: this section is spray type, the mass concentration of hydrochloric acid is 5.0%, the balance is tap water, the temperature is 25±1°C, the length of the water washing section is 2.0 m; the line speed is 2.0±0.2 m / min, and the pressure is 1.5±0.5 kg / cm 2 ; The S7 water washing section is used to wash the printed circuit board that has passed through the S6 hydrochloric acid washing section with tap water. The process parameters of the water washing section are: this section is immersion type, the water washing temperature is 25±1°C, the water washing section length is 1.0m, and the line speed is 2.0±0.2m / min; The S8 surface treatment section is used to perform surface treatment on the printed circuit board that has passed through the S7 water washing section. The used liquid is the PCB inkjet printing pre-treatment agent or PCB inkjet printing anti-diffusion agent of the embodiment / comparative example of the present invention, and the original liquid is used. The process parameters of the surface treatment section are: this section is immersion type, the temperature is 25±1°C, the surface treatment section length is 2.0m; the line speed is 4.0±0.2m / min; The S9 washing section is used to wash the printed circuit board after the S8 surface treatment section with tap water. The process parameters of the washing section are: this section is immersion type, the washing temperature is 25±1°C, the washing section length is 1.0m, and the line speed is 2.0±0.2m / min; The S10 drying section is used to dry the circuit board after the S9 washing section process. The drying process parameters are: temperature 70±5°C, drying section length 2.0m, line speed 4.0±0.2m / min; The S11 inkjet printing section inkjet and cure the printed circuit board after the S10 drying section process. The ink model used is H-9100 of Shenzhen Rongda Photosensitive Technology Co., Ltd. The process parameters of the inkjet printing section are: the printing process is carried out in a clean room environment, the printing temperature is 25±0.5℃, and the curing method is ultraviolet UV curing.

[0055] The performance of the PCB inkjet printing pretreatment agent or PCB inkjet printing anti-diffusion agent of the above-mentioned Examples 1-7 and Comparative Examples 1-15 of the present invention is analyzed from the following three aspects: 1) Anti-diffusion performance: the specific operation is: use a contact angle meter to measure the contact angle between the copper surface and substrate surface of the circuit board after printing and the ink. The larger the contact angle, the better the effect of the pretreatment agent; 2) Adhesion performance was tested using the 3M tape cross-cutting test method. The specific operation was as follows: after the ink on the S11 inkjet printed section was solidified, a cross-cutting tool was used to vertically scratch the surface of the PCB with ink coating to form a grid-like scratch with a grid number of 5*5; the 3M600 test tape was slowly and evenly applied to the cross-cutting area to ensure that the tape was tightly bonded to the ink surface; after standing for 1 minute, the tape was evenly torn off with tweezers to observe the ink shedding in the cross-cutting area.

[0056] Rating is carried out according to the testing standards of ISO2409: Level 0: The edges of the cut are completely smooth, and there is no ink falling off the edges of the grid; Level 1: A little ink falls off at the intersection of the cuts, but the falling area does not exceed 5%; Level 2: Ink falls off at the edges and intersections of the cuts, with the falling area ranging from 5% to 15%; Level 3: The ink falls off obviously along the edge of the cut, and the ink falling off area of ​​some squares is between 15% and 35%; Level 4: The ink falls off over a large area, and the ink falling off area of ​​most squares is between 35% and 65%; Level 5: The ink is almost completely detached, with the detached area exceeding 65%; The test result must reach level 0 or 1 to be qualified; 3) Printing circuit integrity assessment, specifically: take a copper foil board and a substrate board of 50*50 cm in size, use the PCB inkjet printing pretreatment agent or PCB inkjet printing anti-diffusion agent of the above embodiment and comparative example, and according to the specific process flow of fine PCB graphic inkjet printing of the present invention, print ink circuits with a width of 30 μm on the copper foil board and the substrate board respectively, and observe whether there is a break in the ink circuit and whether the circuit shape is uniform and neat.

[0057] The performance test results of the PCB inkjet printing pre-treatment agent using Examples 1-7 are shown in Table 1:

[0058] The copper surface ink circuit of Example 1 is as follows Figure 1 As shown; the ink circuit on the substrate surface of Example 1 is as shown Figure 2 shown.

[0059] It can be seen from the test results of Examples 1-7 in Table 1 that the PCB inkjet printing pretreatment agent of the present invention can form a uniform organic layer on both the copper surface and the substrate surface of the circuit board. The organic layer can not only effectively reduce the surface tension of the copper surface and the substrate surface, prevent the ink from spreading on the PCB surface, but also promote the uniform distribution of the ink, which is conducive to forming a stable and neat linear ink; in the contact angle test, the contact angles of the copper surface, the substrate surface and the ink are all greater than 80°; in the adhesion test, the adhesion level of the ink to the copper surface and the substrate surface is 0; in the circuit integrity test, 30μm ink circuits are printed on the copper surface and the substrate surface, and the circuits remain intact and uniform, which is suitable for fine circuit inkjet printing process.

[0060] The performance test results of the PCB inkjet printing pretreatment agent or PCB inkjet printing anti-diffusion agent of Comparative Examples 1-15 are shown in Table 2:

[0061] The copper surface ink circuit of comparative example 1 is as follows Figure 3 As shown; the ink circuit on the substrate surface of Comparative Example 1 is as shown Figure 4 shown.

[0062] The difference between the PCB inkjet printing pretreatment agent of Comparative Examples 1-5 and Example 1 is that they lack a single component of anti-diffusion agent, wetting agent, leveling agent, dispersant, and cosolvent. The test results in Table 2 show that the anti-diffusion agent helps to improve the aggregation of solder mask printing ink on the copper surface and the substrate surface, and prevent the ink from spreading around. If the anti-diffusion agent is missing in the component, the ink contact angle on the copper surface and the substrate surface will be greatly reduced, and the ink cannot stand up on the PCB surface, which will also affect the adhesion and circuit integrity; the three components of wetting agent, leveling agent, and dispersant can improve the dispersibility, fluidity and uniformity of each component in the pretreatment agent, and ensure that the effective substances act evenly and quickly on the PCB surface. When one of the components of wetting agent, leveling agent, and dispersant is missing, the ink contact angle, adhesion, and circuit integrity test results will all decline. It can be seen that the entire system requires the synergistic effect of the three to be completed together; the cosolvent is used to dissolve the components that are insoluble in water in the component to form a relatively stable solution. If this component is missing, the solution stability system cannot be formed, and the test results of various tests will decline significantly. From the comparison of the test results of Example 1 and Comparative Examples 1-5, it can be seen that the PCB inkjet printing pretreatment agent of the present invention is formed by the joint action of the five components of the anti-diffusion agent, the wetting agent, the homogenizer, the dispersant, and the co-solvent, and none of them can be missing.

[0063] In the PCB inkjet printing pretreatment agents of comparative examples 6-10, the anti-diffusion agent, wetting agent, leveling agent, dispersant, and co-solvent are respectively higher than the upper limit of the concentration of the PCB inkjet printing pretreatment agent of the present invention. The test results in Table 2 show that compared with Examples 1-5, the concentrations of the anti-diffusion agent, wetting agent, leveling agent, dispersant, and co-solvent are too high, and the test results have little effect, indicating that the excessively high concentration has almost no effect on the surface energy of the organic layer formed on the PCB surface, and the ink contact angle, adhesion, and circuit integrity test results are close to those of the embodiments, but too high a concentration will increase the cost of the liquid medicine. Considering the cost factor, the concentrations of these five components in the anti-diffusion liquid of the present invention should not be too high, and the normal effect of the liquid medicine can be guaranteed within the concentration range of the embodiments.

[0064] The test results of comparative examples 11-14 show that anti-diffusion agents, wetting agents, homogenizers and dispersants with different types of branched functional groups will also affect the performance of the PCB inkjet printing pretreatment agent of the present invention, and the effect replacement cannot be achieved. The ink contact angle, adhesion and circuit integrity test results are poor.

[0065] The test results of Comparative Example 15 show that the PCB inkjet printing anti-diffusion agent of the prior art is not as effective as the PCB inkjet printing pretreatment agent of the present invention when used for PCB inkjet printing. The PCB inkjet printing pretreatment agent of the present invention has better anti-diffusion performance and ink adhesion for the ink on the copper surface and substrate surface of the circuit board, and is suitable for more sophisticated inkjet printing circuits.

[0066] In summary, the PCB inkjet printing pretreatment agent provided by the present invention can be used in the surface treatment process of the fine PCB graphic inkjet printing process, and can form a uniform organic layer on the copper surface of the circuit board and the surface of the substrate. The organic layer can not only effectively reduce the surface tension of the copper surface and the surface of the substrate, and prevent the printing ink from diffusing on the PCB surface, but also promote the uniform distribution of the ink, which is conducive to forming a stable and neat linear ink, and improving the product yield of the fine line inkjet printing process.

[0067] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A PCB inkjet printing pre-treatment agent, characterized in that: It is composed of the following components in mass concentration: Anti-diffusion agent 0.1-0.5%, Wetting agent 0.1-0.5%, Leveling agent 0.2-1.0%, Dispersant 0.5-2.5%, Solvent 0.1-3.0%, The balance is water; The anti-diffusion agent is a fluorobenzenethiophenol compound, the wetting agent is a polyethylene glycol acrylate compound, the homogenizing agent is a carboxylic acid phenyl ester compound, the dispersant is a carboxybenzocrown ether compound, and the cosolvent is a pinacol ester compound.

2. The PCB inkjet printing pre-treatment agent according to claim 1, characterized in that: The anti-diffusion agent is selected from at least one of 2,4-difluorobenzenethiol, 3,4-difluorobenzenethiol and 3,5-difluorobenzenethiol.

3. The PCB inkjet printing pre-treatment agent according to claim 1, characterized in that: The wetting agent is selected from at least one of methoxy polyethylene glycol acrylate, polyethylene glycol methacrylate and polyethylene glycol monoacrylate.

4. The PCB inkjet printing pre-treatment agent according to claim 1, characterized in that: The homogenizer is selected from at least one of diphenyl phenylphosphonate, diphenyl malonate and benzyl glycolate.

5. The PCB inkjet printing pre-treatment agent according to claim 1, characterized in that: The dispersant is selected from at least one of 4'-carboxybenzo-15-crown-5-ether and 4'-carboxybenzo-18-crown-6-ether.

6. The PCB inkjet printing pre-treatment agent according to claim 1, characterized in that: The cosolvent is selected from at least one of 6-quinolineboronic acid pinacol ester and 4-benzylphenylboronic acid pinacol ester.

7. The method for preparing a PCB inkjet printing pre-treatment agent according to any one of claims 1 to 6, characterized in that: The anti-diffusion agent, wetting agent, homogenizing agent, dispersant, co-solvent and water are placed in a reaction container, mixed evenly at 55-65° C., and cooled to room temperature to obtain the PCB inkjet printing pre-treatment agent.

8. A PCB inkjet printing method, characterized in that: The following steps are involved: Surface treatment: soak the PCB in the PCB inkjet printing pre-treatment agent as described in any one of claims 1 to 6 for 1.5 to 3 minutes; Inkjet printing: Inkjet and cure the surface treated PCB.

9. The PCB inkjet printing method according to claim 8, characterized in that: Before surface treatment, ultra-roughening treatment is also included: ultra-roughening etching is performed on the PCB.

10. The PCB inkjet printing method according to claim 9, characterized in that: The ultra-roughening etching amount is 0.8-1.0 μm.

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