Circuit board solder resist and use method thereof

Abstract

The invention relates to the technical field of electronic industry. The invention discloses a circuit board solder resist and a use method thereof. The circuit board solder resist comprises the following raw materials: a resin base material, a filler, a diluent, a cross-linking agent, a photoinitiator, a defoaming agent, nicotinamide and polyacrylic acid intercalated hydrotalcite. The use method comprises the following steps: S1, polishing the surface of a PCB, and removing an oxide layer; s2, printing a circuit board solder resist on the PCB by using a screen printing machine; s3, the printed PCB is dried at the temperature of 80 DEG C to 100 DEG C for 15 min to 30 min; and S4, exposing, soaking the PCB by using a developing solution, and washing with clear water. The circuit board solder resist prepared by the invention is good in stability and free of bubble phenomenon.

Description

Technical Field

[0001] The present application relates to the technical field of electronic industry, and in particular to a circuit board solder resist and a method for using the same. Background Art

[0002] With the diversification and sophistication of electronic products, printed circuit boards (PCBs) are also developing in the direction of diversification and sophistication. PCBs are not only carriers of electronic components, but also provide the function of electrical connection to ensure that the circuit can work properly. In the PCB manufacturing process, solder resist plays a vital role as a protective coating. It is usually coated on the entire circuit board, except for pads and other areas that need to be soldered, to prevent soldering materials from adhering to locations where soldering is not required. Solder resist not only protects the circuit board from environmental factors such as oxidation and corrosion, but also prevents the unexpected flow of solder during soldering to avoid short circuits. In modern PCB manufacturing, solder resist is not only a key factor in improving the reliability and durability of circuit boards, but also improves the appearance of circuit boards.

[0003] The solder resist widely used in the market has good insulation performance and mechanical strength. However, with the increasing miniaturization and multifunctionality of electronic products, the design of PCBs tends to be more integrated and more complex, and traditional solder resists are gradually showing their limitations. For example, during the development process, the existing solder resist is easily corroded, resulting in its structural instability, increasing the difficulty of production and the defect rate. Especially for PCBs with high aspect ratio vias and extremely narrow solder bridges, the problem of insufficient or excessive development during the development process is particularly prominent. In addition, during the solder resist coating process, if the operation is not done properly, air may be introduced, especially during screen printing or spraying. This air is trapped in the solder resist layer, and during the curing process, due to the thermal effect, it expands to form bubbles, which may cause delamination or peeling between the solder resist layer and the underlying substrate or copper foil. This situation not only affects the protective performance of the solder resist layer, but also reduces the reliability and service life of the circuit board.

[0004] Therefore, it is urgent to develop a circuit board solder resist with good stability and no bubble phenomenon. Summary of the invention

[0005] In order to solve at least one of the above technical problems, a circuit board solder resist with good stability and no bubble phenomenon is developed. The present application provides a circuit board solder resist and a method for using the same.

[0006] On the one hand, the present application provides a circuit board solder resist, whose raw material composition includes, by weight: 30 to 60 parts of resin base material, 20 to 30 parts of filler, 10 to 25 parts of diluent, 2 to 5 parts of cross-linking agent, 1 to 5 parts of photoinitiator, 0.1 to 1 part of defoaming agent, 0.1 to 1 part of niacinamide, and 0.5 to 5 parts of polyacrylic acid intercalated hydrotalcite.

[0007] By adopting the above technical solution, the present application adopts specific raw materials and formulas to prepare a circuit board solder resist with good stability and no bubble phenomenon, thus solving the problems of traditional solder resist being easily corroded during the development process, insufficient or excessive development, and easy generation of bubbles during the coating process.

[0008] The filler of the present application can improve the density of the solder resist layer and reduce bubble formation; the diluent can optimize the rheological properties of the solder resist and reduce bubbles during the coating process; the photoinitiator can improve the curing speed and quality and reduce bubble formation; the defoamer can significantly reduce bubbles and improve the stability of the solder resist.

[0009] The application adds nicotinamide, which can further improve the rheological properties and defoaming effect of the solder mask, and adds polyacrylic acid intercalated hydrotalcite, which can provide mechanical properties and dispersibility and reduce bubble formation. Nicotinamide and polyacrylic acid intercalated hydrotalcite work together to further optimize the comprehensive performance of the circuit board solder mask and reduce bubble formation.

[0010] Optionally, the resin base material is selected from one of epoxy resin, acrylic resin, polyurethane resin and polyester resin.

[0011] By adopting the above technical solution, the resin base material added in the present application has good mechanical strength and excellent chemical stability, and also helps to improve the leveling property of the solder resist and reduce bubble formation.

[0012] Optionally, the filler is selected from at least one of silicon dioxide, talc and mica powder.

[0013] By adopting the above technical solution, the filler of the present application has high mechanical properties and good dispersibility, can improve the stability of the solder resist, and can also improve the rheological properties of the solder resist, making it easier to apply and reducing the formation of bubbles.

[0014] Optionally, the average particle size of the filler is 10 to 100 nm.

[0015] By adopting the above technical solution, the average particle size of the filler of the present application enables it to be dispersed more evenly, improving the surface smoothness of the solder resist layer; the nanoscale filler can improve the rheological properties of the resin base material, reduce the formation of bubbles during the coating process, and improve the uniformity and density of the solder resist layer; it can also enhance the stability of the solder resist and reduce erosion during the development process. If the average particle size is too large, it may cause unevenness during the coating process, increase the risk of bubble formation, and may also reduce the stability of the solder resist and increase the risk of erosion during the development process. If the average particle size is too small, it may cause filler agglomeration, affect dispersibility, and reduce the performance of the solder resist.

[0016] Optionally, the diluent is selected from at least one of ethyl acetate, cyclohexanone, propylene glycol methyl ether acetate and isophorone.

[0017] By adopting the above technical solution, the diluent of the present application can significantly improve the rheological properties, coating properties and curing effect of the solder resist.

[0018] Optionally, the crosslinking agent is selected from at least one of trimethylolpropane triacrylate, diethylenetriamine and triethylenetetramine.

[0019] By adopting the above technical solution, the cross-linking agent of the present application can significantly improve the curing effect of the solder resist, accelerate the curing process, shorten the production cycle, and improve production efficiency. It can also improve the stability of the solder resist and reduce erosion during the development process.

[0020] Optionally, the photoinitiator is selected from at least one of 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0021] By adopting the above technical solution, the photoinitiator of the present application can significantly improve the curing effect, curing speed and photosensitivity of the solder resist.

[0022] Optionally, the defoaming agent is selected from at least one of polydimethylsiloxane, white oil and polyoxyethylene-polyoxypropylene block copolymer.

[0023] By adopting the above technical scheme, the defoaming agent of the present application can quickly destroy the stability of the foam and eliminate bubbles. Under the joint action, the defoaming effect of the solder resist can be significantly improved, and both have good stability, which can ensure the stable performance of the solder resist during storage and use.

[0024] Optionally, the weight ratio of the nicotinamide to the polyacrylic acid intercalated hydrotalcite is 1:2-8.

[0025] By adopting the above technical solution, the weight ratio of nicotinamide and polyacrylic acid intercalated hydrotalcite in the present application can optimize the rheological properties of the solder resist, improve the defoaming effect, and enhance the stability.

[0026] In a second aspect, the present application provides a method for using the above-mentioned circuit board solder resist, comprising the following steps: S1. Polish the PCB surface and remove the oxide layer; S2. Print the circuit board solder resist onto the PCB using a screen printer; S3, drying the printed PCB at 80-100°C for 15-30 minutes; S4, exposure, soak the PCB in developer and rinse with water.

[0027] By adopting the above technical solution, the method for using the solder resist of the circuit board of the present application ensures uniform coating and effective curing of the solder resist on the PCB, has higher adhesion, precise thickness control, reduces bubble formation, and improves curing effect. First, remove the oxide layer to ensure good adhesion of the solder resist to the surface of the PCB and improve the adhesion of the solder resist; screen printing can accurately control the thickness of the solder resist to avoid being too thick or too thin, which affects the performance of the solder resist, and can also ensure the uniform distribution of the solder resist on the PCB and reduce bubble formation; drying can reduce the moisture in the solder resist and reduce bubble formation during the curing process; exposure can cure the solder resist in the unexposed area to form a protective layer; the developer can remove the solder resist in the unexposed area, leaving the desired pattern.

[0028] In summary, the present invention includes at least one of the following beneficial technical effects: 1. This application adopts specific raw materials and formulas, and the circuit board solder resist prepared has good stability and no bubble phenomenon.

[0029] 2. Nicotinamide is added to the present application to further improve the rheological properties and defoaming effect of the solder resist.

[0030] 3. The nicotinamide and polyacrylic acid intercalated hydrotalcite of the present application work together to further optimize the comprehensive performance of the circuit board solder resist and reduce bubble formation.

[0031] 4. The method for using the solder resist of the circuit board of the present application ensures uniform coating and effective curing of the solder resist on the PCB and reduces bubble formation. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the embodiments.

[0033] The present application designs a circuit board solder resist, and its raw material composition includes, by weight: 30 to 60 parts of resin base material, 20 to 30 parts of filler, 10 to 25 parts of diluent, 2 to 5 parts of cross-linking agent, 1 to 5 parts of photoinitiator, 0.1 to 1 part of defoaming agent, 0.1 to 1 part of nicotinamide, and 0.5 to 5 parts of polyacrylic acid intercalated hydrotalcite.

[0034] The method for using the circuit board solder resist of the present application comprises the following steps: S1. Polish the PCB surface and remove the oxide layer; S2. Print the circuit board solder resist onto the PCB using a screen printer; S3, drying the printed PCB at 80-100°C for 15-30 minutes; S4, exposure, soak the PCB in developer and rinse with water.

[0035] The applicant has designed the technical solution of the present application to solve the problems of poor stability and bubble phenomenon of the existing solder resist for circuit boards.

[0036] The raw materials used in this application are as follows: Epoxy resin: CAS: 24969-06-0.

[0037] Polyester resin: CAS: 109-16-0.

[0038] Silicon dioxide: CAS: 14808-60-7.

[0039] Talc: CAS: 14807-96-6.

[0040] Ethyl acetate: CAS: 141-78-6.

[0041] Isophorone: CAS: 78-59-1.

[0042] Trimethylolpropane triacrylate: CAS: 15625-89-5.

[0043] Diethylenetriamine: CAS: 111-40-0.

[0044] 2,2-Dimethoxy-2-phenylacetophenone: CAS: 24650-42-8.

[0045] 1-Hydroxycyclohexylphenyl ketone: CAS: 947-19-3.

[0046] Polydimethylsiloxane: CAS: 9016-00-6.

[0047] White oil: CAS: 8042-47-5.

[0048] Niacinamide: CAS: 98-92-0.

[0049] Mg(NO3)2·6H2O (magnesium nitrate hexahydrate): CAS: 13446-18-9.

[0050] Al(NO3)3·9H2O (aluminum nitrate nonahydrate): CAS: 7784-27-2.

[0051] Polyacrylic acid: CAS: 9003-01-4.

[0052] Potassium persulfate: CAS: 7727-21-1. Specific embodiments

[0053] The preparation method of the polyacrylic acid intercalated hydrotalcite used in Examples 1 to 3 is: Mix Mg(NO3)2·6H2O and Al(NO3)3·9H2O, add water to dissolve, and prepare a mixed salt solution; Mg 2+ and Al 3+ The molar ratio is 3:1; a sodium hydroxide solution with a mass fraction of 5% is added dropwise to the mixed salt solution, stirred to generate a precipitate, separated, washed, and dried to obtain a basic hydrotalcite; the basic hydrotalcite is ultrasonically dispersed in water to obtain a hydrotalcite suspension; polyacrylic acid is added to the hydrotalcite suspension, potassium persulfate is added, stirred at 70°C for 7h, separated, washed, and dried to obtain a polyacrylic acid intercalated hydrotalcite.

[0054] Examples 1 to 3 Example 1 The present embodiment provides a circuit board solder resist, and its raw material composition includes, by weight: 60 parts of resin base material, 20 parts of filler, 10 parts of diluent, 5 parts of cross-linking agent, 1 part of photoinitiator, 1 part of defoamer, 0.1 parts of nicotinamide, and 0.5 parts of polyacrylic acid intercalated hydrotalcite; Among them, the resin base material is epoxy resin; the filler is talcum powder; the average particle size of the filler is 55nm; the diluent is ethyl acetate; the cross-linking agent is trimethylolpropane triacrylate; the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone; and the defoaming agent is polydimethylsiloxane.

[0055] The preparation method is: Step 1: stir and mix the resin base material and the diluent, add the cross-linking agent, the photoinitiator, the defoaming agent, and the nicotinamide in sequence, stir and mix, and prepare a premix; Step 2: adding filler to the premix, stirring and mixing, and adding polyacrylic acid intercalated hydrotalcite to prepare a mixture; Step 3: homogenize and filter the mixture to obtain the circuit board solder resist.

[0056] The method of use includes the following steps: S1. Polish the PCB surface and remove the oxide layer; S2. Print the circuit board solder resist onto the PCB using a screen printer; S3, drying the printed PCB at 80°C for 30 minutes; S4, exposure, soak the PCB in developer and rinse with water.

[0057] Example 2 This embodiment provides a circuit board solder resist, and its raw material composition includes, by weight: 45 parts of resin base material, 25 parts of filler, 17 parts of diluent, 3.5 parts of cross-linking agent, 3 parts of photoinitiator, 0.5 parts of defoaming agent, 0.5 parts of nicotinamide, and 2.5 parts of polyacrylic acid intercalated hydrotalcite; Among them, the resin base material is epoxy resin; the filler is talcum powder; the average particle size of the filler is 55nm; the diluent is ethyl acetate; the cross-linking agent is trimethylolpropane triacrylate; the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone; and the defoaming agent is polydimethylsiloxane.

[0058] The preparation method is: Step 1: stir and mix the resin base material and the diluent, add the cross-linking agent, the photoinitiator, the defoaming agent, and the nicotinamide in sequence, stir and mix, and prepare a premix; Step 2: adding filler to the premix, stirring and mixing, and adding polyacrylic acid intercalated hydrotalcite to prepare a mixture; Step 3: homogenize and filter the mixture to obtain the circuit board solder resist.

[0059] The method of use includes the following steps: S1. Polish the PCB surface and remove the oxide layer; S2. Print the circuit board solder resist onto the PCB using a screen printer; S3, drying the printed PCB at 90°C for 22 minutes; S4, exposure, soak the PCB in developer and rinse with water.

[0060] Example 3 This embodiment provides a circuit board solder resist, and its raw material composition includes, by weight: 30 parts of resin base material, 30 parts of filler, 25 parts of diluent, 2 parts of cross-linking agent, 5 parts of photoinitiator, 0.1 parts of defoaming agent, 1 part of nicotinamide, and 5 parts of polyacrylic acid intercalated hydrotalcite; Among them, the resin base material is epoxy resin; the filler is talcum powder; the average particle size of the filler is 55nm; the diluent is ethyl acetate; the cross-linking agent is trimethylolpropane triacrylate; the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone; and the defoaming agent is polydimethylsiloxane.

[0061] The preparation method is: Step 1: stir and mix the resin base material and the diluent, add the cross-linking agent, the photoinitiator, the defoaming agent, and the nicotinamide in sequence, stir and mix, and prepare a premix; Step 2: adding filler to the premix, stirring and mixing, and adding polyacrylic acid intercalated hydrotalcite to prepare a mixture; Step 3: homogenize and filter the mixture to obtain the circuit board solder resist.

[0062] The method of use includes the following steps: S1. Polish the PCB surface and remove the oxide layer; S2. Print the circuit board solder resist onto the PCB using a screen printer; S3, drying the printed PCB at 100°C for 15 minutes; S4, exposure, soak the PCB in developer and rinse with water.

[0063] Comparative Examples 1 to 3 Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that nicotinamide and polyacrylic acid intercalated hydrotalcite are not added in Comparative Example 1.

[0064] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that nicotinamide is not added in Comparative Example 2.

[0065] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that no polyacrylic acid intercalated hydrotalcite is added in Comparative Example 3.

[0066] Experimental testing Test items and test method stability: According to SJ / T 10309-2016 "Solder Resists for Printed Circuit Boards", the prepared solder resist is tested for chemical resistance and hydrolysis stability; Bubble phenomenon: Observe whether there are bubbles in the solder resist layer after curing.

[0067] The circuit board solder resists prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were tested for chemical resistance and hydrolysis stability, and whether bubbles were generated in the solder resist layer after curing was observed. The test results are shown in Table 1.

[0068] Table 1 From the test results in Table 1, it can be seen that the circuit board solder resists prepared in Examples 1 to 3 have good stability and no bubble phenomenon.

[0069] Comparative Example 1 did not add nicotinamide and polyacrylic acid intercalated hydrotalcite, Comparative Example 2 did not add nicotinamide, and Comparative Example 3 did not add polyacrylic acid intercalated hydrotalcite. The stability of the circuit board solder resists prepared in Comparative Examples 1 to 3 was not as good as that in Example 2, and bubbles appeared in Comparative Example 1.

[0070] Embodiments 4 to 13 Example 4 The difference between Example 4 and Example 2 is that in Example 4, the resin base material is polyester resin.

[0071] Example 5 The difference between Example 5 and Example 2 is that in Example 5, the filler is silicon dioxide.

[0072] Example 6 The difference between Example 6 and Example 2 is that in Example 6, the average particle size of the filler is 10 nm.

[0073] Example 7 The difference between Example 7 and Example 2 is that in Example 7, the average particle size of the filler is 100 nm.

[0074] Example 8 The difference between Example 8 and Example 2 is that in Example 8, the diluent is isophorone.

[0075] Example 9 The difference between Example 9 and Example 2 is that in Example 9, the cross-linking agent is diethylenetriamine.

[0076] Example 10 The difference between Example 10 and Example 2 is that in Example 10, the photoinitiator is 1-hydroxycyclohexyl phenyl ketone.

[0077] Embodiment 11 The difference between Example 11 and Example 2 is that in Example 11, the defoaming agent is white oil.

[0078] Example 12 The difference between Example 12 and Example 2 is that in Example 12, the weight ratio of nicotinamide and polyacrylic acid intercalated hydrotalcite is 1:2, and the total weight of nicotinamide and polyacrylic acid intercalated hydrotalcite is 3.

[0079] Embodiment 13 The difference between Example 13 and Example 2 is that in Example 13, the weight ratio of nicotinamide and polyacrylic acid intercalated hydrotalcite is 1:8, and the total weight of nicotinamide and polyacrylic acid intercalated hydrotalcite is 3.

[0080] The circuit board solder resists prepared in Examples 4 to 13 were tested for chemical resistance and hydrolysis stability, and the cured solder resist layer was observed to see whether bubbles were generated. The test results are shown in Table 2.

[0081] Table 2 From the test results in Table 2, it can be seen that the circuit board solder resists prepared in Examples 4 and 5 have good stability and no bubble phenomenon.

[0082] The difference between Example 6 and Example 7 and Example 2 is that the average particle size of the filler is different, and the stability of the obtained circuit board solder resist is not as good as that of Example 2.

[0083] The stability of the circuit board solder resists prepared in Examples 8 to 11 is similar to that in Example 2, and there is no bubble phenomenon.

[0084] The difference between Example 12 and Example 13 and Example 2 is that the weight ratios of nicotinamide and polyacrylic acid intercalated hydrotalcite are different, and the prepared circuit board solder resist has slight bubbles.

[0085] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A circuit board solder resist, characterized in that: The raw material composition includes, by weight, 30-60 parts of resin base material, 20-30 parts of filler, 10-25 parts of diluent, 2-5 parts of cross-linking agent, 1-5 parts of photoinitiator, 0.1-1 parts of defoaming agent, 0.1-1 parts of nicotinamide, and 0.5-5 parts of polyacrylic acid intercalated hydrotalcite.

2. The circuit board solder resist according to claim 1, wherein: The resin base material is selected from one of epoxy resin, acrylic resin, polyurethane resin and polyester resin.

3. The circuit board solder resist according to claim 1, wherein: The filler is selected from at least one of silicon dioxide, talc powder and mica powder.

4. The circuit board solder resist according to claim 1, wherein The average particle size of the filler is 10-100 nm.

5. The circuit board solder resist according to claim 1, wherein: The diluent is selected from at least one of ethyl acetate, cyclohexanone, propylene glycol methyl ether acetate and isophorone.

6. The circuit board solder resist according to claim 1, wherein: The crosslinking agent is selected from at least one of trimethylolpropane triacrylate, diethylenetriamine and triethylenetetramine.

7. The circuit board solder resist according to claim 1, wherein: The photoinitiator is selected from at least one of 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

8. The circuit board solder resist according to claim 1, wherein: The defoaming agent is selected from at least one of polydimethylsiloxane, white oil and polyoxyethylene-polyoxypropylene block copolymer.

9. The circuit board solder resist according to claim 1, wherein: The weight ratio of the nicotinamide to the polyacrylic acid intercalated hydrotalcite is 1:2-8.

10. A method for using the circuit board solder resist according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Polish the PCB surface to remove the oxide layer; S2. Use a screen printer to print the solder resist onto the PCB. S3. Dry the printed PCB at 80-100°C for 15-30 minutes; S4. Expose, soak the PCB in developer and rinse with water.

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