Environment-friendly film removing liquid and preparation method thereof

Abstract

The invention relates to the field of environment-friendly circuit board processing, and discloses environment-friendly film removing liquid and a preparation method thereof. The environment-friendly film removing liquid is prepared from the following raw materials in percentage by weight: 2-4% of basic hydroxide, 3-5% of diethylene glycol monobutyl ether, 3.5-5.5% of tetrahydrofurfuryl alcohol, 2-4% of ethylene glycol hexyl ether, 3-5% of an accelerating agent, 4-6% of a stabilizer and the balance of water. The stabilizer is prepared from hydroxypropyl chitosan, N-tri (hydroxymethyl) methylglycine, quaternary ammonium salt and water. The environment-friendly film removing liquid is suitable for a high-precision PCB processing technology, has good environmental protection performance and dry film removing efficiency, and meanwhile reduces corrosion to circuit patterns of a PCB.

Description

Technical Field

[0001] The present application relates to the field of environmentally friendly circuit board processing, and more specifically, to an environmentally friendly film removal liquid and a preparation method thereof. Background Art

[0002] With the rapid development of the electronics industry, electronic products are pursuing miniaturization and lightweight, making the wiring of PCB boards more and more precise. As the basic component of electronic products, the manufacturing process of PCB boards directly affects the performance and reliability of the products. In the manufacturing process of PCB boards, dry film technology is widely used in pattern transfer. The dry film is attached to the PCB board through ultraviolet irradiation, thereby realizing the precise transfer of circuit patterns and playing a protective role in the subsequent electroplating and etching processes. However, the removal of dry film is one of the key links in the manufacturing process of PCB boards, which directly affects production efficiency and product quality.

[0003] Existing PCB board dry film removers generally use a large amount of strong alkaline substances, such as sodium hydroxide, potassium hydroxide, etc. Strong alkaline substances are highly corrosive and will corrode the surface of the circuit pattern while removing the dry film; or add alcohol amine substances, such as amine solvents such as monoethanolamine, diethanolamine, triethanolamine, isopropanolamine and ethylenediamine, etc. Alcohol amine substances have a strong odor and are added to the film remover. During use, they are prone to emit irritating odors, affecting the production workshop environment and personnel health, and reducing the environmental friendliness of the film remover.

[0004] In order to solve the above-mentioned environmental protection problem, there are some relatively mild film removers in the prior art, which reduce the corrosion inhibition effect on the circuit pattern by adding corrosion inhibitors, such as benzotriazole, mercaptobenzothiazole, etc. However, the addition of corrosion inhibitors will reduce the removal rate of the dry film by the film remover, especially for high-precision PCB boards, where the circuit patterns are arranged more densely, the removal efficiency of the dry film will be lower, thereby affecting the processing efficiency of the PCB board. Summary of the invention

[0005] In order to solve the problem that the existing film removal liquid cannot take into account both environmental protection and film removal efficiency, the present application provides an environmentally friendly film removal liquid and a preparation method thereof.

[0006] In the first aspect, the present application provides an environmentally friendly film removal liquid, which adopts the following technical solution: An environmentally friendly film removal liquid is prepared from the following raw materials in percentage by weight: Alkaline hydroxide 2-4% Diethylene glycol butyl ether 3-5% Tetrahydrofurfuryl alcohol 3.5-5.5% Ethylene glycol hexyl ether 2-4% Speed ​​accelerator 3-5% Stabilizer 4-6% Water balance; The stabilizer is prepared from hydroxypropyl chitosan, N-tri(hydroxymethyl)methylglycine, quaternary ammonium salt and water.

[0007] By adopting the above technical scheme, the environmentally friendly film stripping liquid of the present application is suitable for the processing of high-precision PCB boards, has good dry film removal efficiency, and will not corrode the circuit pattern of the PCB board. The synergistic effect of alkaline hydroxide and diethylene glycol butyl ether, tetrahydrofurfuryl alcohol, and ethylene glycol hexyl ether improves the permeability of the dry film, and the speed increaser improves the dissolution and removal efficiency of the dry film. The stabilizer is composed of hydroxypropyl chitosan, N-tris (hydroxymethyl) methylglycine and quaternary ammonium salt, which can form a uniform adsorption film on the surface of the dry film, further improve the permeability of the environmentally friendly film stripping liquid, thereby enhancing the removal effect, and can play a good protective role on the circuit pattern, reducing the corrosiveness to the circuit pattern. The overall formula does not contain strong alkaline substances, alcohol amine substances and corrosion inhibitor substances, which avoids the corrosion of the circuit pattern and the generation of irritating odors, and improves environmental protection and safety.

[0008] Preferably, the stabilizer is prepared from the following raw materials in weight percentage: Hydroxypropyl chitosan 4-6% N-Tris(hydroxymethyl)methylglycine 2-4% Quaternary ammonium salt 8-10% Water balance.

[0009] By adopting the above technical scheme, the dosage of each component in the stabilizer is further optimized, the synergistic effect of each component is improved, and a uniformly interwoven dispersion system is formed. The system can be evenly dispersed on the surface of the dry film to form an interwoven adsorption film, thereby increasing the contact area between the environmentally friendly film removal liquid and the dry film surface, and can evenly penetrate into the gaps of high-precision circuit patterns, thereby further improving the removal efficiency of the dry film.

[0010] Preferably, the stabilizer is prepared by the following steps: S1. Add hydroxypropyl chitosan and N-tri(hydroxymethyl)methylglycine into water, heat for reaction, and obtain reactant A; S2. Add quaternary ammonium salt into reactant A, mix and stir, and obtain stabilizer.

[0011] By adopting the above technical scheme, hydroxypropyl chitosan and N-tri(hydroxymethyl)methylglycine are heated and reacted in water to form a stable colloidal dispersion system, which is then mixed and stirred with a quaternary ammonium salt, and the molecular chain segments are intertwined and adsorbed to obtain a stabilizer with good adsorption stability.

[0012] Preferably, the reaction temperature in step S1 is 45-65° C., and the reaction time is 1-2 h.

[0013] By adopting the above technical solution, the reaction temperature in the stabilizer preparation process is controlled to be 45-65°C and the reaction time is 1-2h, which can ensure that hydroxypropyl chitosan and N-tris(hydroxymethyl)methylglycine fully react to form a uniformly dispersed colloidal system.

[0014] Preferably, the quaternary ammonium salt is one or a combination of polyquaternium-7, polyquaternium-39, and silicone long-chain quaternary ammonium salt.

[0015] By adopting the above technical scheme, one or a combination of polyquaternium-7, polyquaternium-39, and silicone long-chain quaternary ammonium salt is selected as the quaternary ammonium salt, which can effectively improve the stability of the stabilizer, enhance the adsorption capacity of the stabilizer on the dry film surface, and further improve the permeability and removal efficiency of the film removal solution.

[0016] Preferably, the quaternary ammonium salt is composed of quaternary ammonium salt-39 and organosilicon long-chain quaternary ammonium salt in a weight ratio of 1:(1-2).

[0017] By adopting the above technical solution, quaternary ammonium salt-39 has good penetration and corrosion inhibition effects, while silicone long-chain quaternary ammonium salt can effectively improve the wettability and dispersibility of the stabilizer. The two work synergistically to enhance the penetration and removal performance of the stripping liquid on the dry film, while reducing the risk of corrosion to the circuit pattern.

[0018] Preferably, the speed increasing agent is composed of potassium silicate, potassium persulfate and sodium N-hydroxymethylglycinate in a weight ratio of (1-2):1:(2-3).

[0019] By adopting the above technical solution, potassium silicate, potassium persulfate and sodium N-hydroxymethylglycinate in a relatively optimal weight ratio are used as accelerators, and the stabilizer has a good synergistic effect, which can accelerate the erosion process of the dry film and improve the removal efficiency of the dry film. At the same time, the stability of the film stripping solution can be maintained, the adverse reactions between chemical components can be reduced, and the corrosion performance to the circuit pattern can be reduced. Preferably, the alkaline hydroxide is one or a combination of sodium hydroxide, potassium hydroxide and barium hydroxide.

[0020] By adopting the above technical solution, the above alkaline hydroxide can improve the alkalinity of the film removal solution when the added amount is relatively small, so that the film removal solution has better environmental protection and better film removal efficiency.

[0021] In a second aspect, the present application provides a method for preparing an environmentally friendly film removal solution, using the following technical solution: A method for preparing an environmentally friendly film removal liquid comprises the following steps: adding alkaline hydroxide and an accelerating agent into water, stirring and dissolving them, adding diethylene glycol butyl ether, ethylene glycol hexyl ether and tetrahydrofurfuryl alcohol, stirring them evenly, adding a stabilizer, stirring them evenly, and preparing the environmentally friendly film removal liquid.

[0022] By adopting the above technical scheme, the preparation method of the environmentally friendly film removing liquid can ensure that the components are fully and evenly mixed, the entire preparation process is simple and efficient, and the system of the prepared environmentally friendly film removing liquid is evenly dispersed and stable.

[0023] In summary, this application has the following beneficial effects: 1. The environmentally friendly film removal liquid is prepared by compounding alkaline hydroxide, diethylene glycol butyl ether, tetrahydrofurfuryl alcohol, ethylene glycol hexyl ether, accelerator and stabilizer. It is suitable for the treatment of high-precision PCB boards, has good environmental protection and dry film removal efficiency, and will not corrode the circuit pattern.

[0024] 2. The stabilizer is prepared by compounding hydroxypropyl chitosan, N-tri(hydroxymethyl)methylglycine, quaternary ammonium salt and water, which can form a uniform adsorption film on the surface of the dry film, enhance the penetration ability of the film stripping solution, further improve the removal efficiency of the dry film, and prevent the corrosion of the PCB board circuit pattern during the film stripping process.

[0025] 3. The accelerator is compounded with potassium silicate, potassium persulfate and sodium N-hydroxymethylglycine, which has a good synergistic effect with the stabilizer, can accelerate the bite process of the dry film, improve the removal efficiency of the dry film, and prevent the corrosion of the PCB board circuit pattern during the film removal process. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to the embodiments.

[0027] The following are the sources and specifications of some raw materials of this application. The raw materials used in the preparation examples and embodiments of this application can be obtained from the market, including but not limited to the raw materials of the following models and manufacturers. Raw materials with equivalent performance can be used: 1. Hydroxypropyl chitosan: Pingju Biotechnology, deacetylation degree 95%, content 98%; 2. N-Tris(hydroxymethyl)methylglycine: CAS No. 5704-04-1, content 99%; 3. Organic silicon long-chain quaternary ammonium salt: octadecyldimethyltrimethylsilylpropylammonium chloride, CAS No. 27668-52-6; 4. Sodium N-hydroxymethylglycinate: CAS No. 70161-44-3, content ≥ 99%.

[0028] Preparation example of stabilizer Preparation Example 1 Preparation Example 1 provides a stabilizer, which is prepared by the following steps: S1, adding 0.4 kg of hydroxypropyl chitosan and 0.4 kg of N-tris(hydroxymethyl)methylglycine to 8.2 kg of water, heating to 45°C, reacting for 2 hours, to obtain reactant A; S2. Add 1 kg of quaternary ammonium salt (composed of 0.5 kg of tetramethylammonium hydroxide and 0.5 kg of dodecyldimethylbenzylammonium chloride) to reactant A, and mix for 45 min at a mixing rate of 300 r / min to obtain a stabilizer.

[0029] Preparation Example 2-3 The difference between Preparation Example 2-3 and Preparation Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 1 below for details.

[0030] Table 1 Parameters of Preparation Examples 1-3 Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that the quaternary ammonium salt is different. The quaternary ammonium salt in Preparation Example 4 is composed of 0.5 kg of tetramethylammonium hydroxide and 0.5 kg of polyquaternium-39, and the rest is the same as Preparation Example 1.

[0031] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 4 is that the quaternary ammonium salt in Preparation Example 5 is composed of 0.5 kg of organosilicon long-chain quaternary ammonium salt and 0.5 kg of polyquaternium-39, and the rest is the same as Preparation Example 4.

[0032] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 4 is that the quaternary ammonium salt in Preparation Example 4 is composed of 0.67 kg of organosilicon long-chain quaternary ammonium salt and 0.33 kg of polyquaternium-39, and the rest is the same as Preparation Example 4.

[0033] Preparation Comparative Example 1 The difference between Preparation Comparative Example 1 and Preparation Example 5 is that an equal amount of N-tris(hydroxymethyl)methylglycine is replaced by hydroxypropyl chitosan, and the rest is the same as Preparation Example 5.

[0034] Preparation Comparative Example 2 The difference between Preparation Comparative Example 2 and Preparation Example 5 is that an equal amount of quaternary ammonium salt is replaced with hydroxypropyl chitosan, and the rest is the same as Preparation Example 5. Example

[0035] Example 1 Example 1 discloses an environmentally friendly film removal liquid, which is prepared by the following steps: 0.3 kg of potassium hydroxide as an alkaline hydroxide and 0.5 kg of an accelerating agent (composed of ammonium persulfate and potassium silicate in a weight ratio of 1:1) are added to 7.65 kg of water, and after stirring to dissolve, 0.5 kg of diethylene glycol butyl ether, 0.2 kg of ethylene glycol hexyl ether and 0.45 kg of tetrahydrofurfuryl alcohol are added, and after stirring evenly, 0.4 kg of the stabilizer prepared in Preparation Example 1 is added, and stirred evenly to prepare an environmentally friendly film removal liquid Example 2-3 The difference between Example 2-3 and Example 1 is that the amount of raw materials used and the preparation process are different, see Table 2 below for details.

[0036] Table 2 Parameters of Examples 1-3 Embodiment 4-6 The difference between Examples 4-6 and Example 1 is that the sources of the stabilizer are different, see Table 3 below for details.

[0037] Table 3 Sources of stabilizers for Examples 4-6 Example Stabilizer Source Table Example 4 Preparation Example 4 Example 5 Preparation Example 5 Example 6 Preparation Example 6 Example 7 The difference between Example 7 and Example 5 is that the speed increasing agent in Example 7 is composed of potassium silicate, potassium persulfate and sodium N-hydroxymethylglycinate in a weight ratio of 1:1:2, and the rest is the same as Example 5.

[0038] Example 8 The difference between Example 8 and Example 5 is that the speed increasing agent in Example 8 is composed of potassium silicate, potassium persulfate and sodium N-hydroxymethylglycinate in a weight ratio of 1:2:3, and the rest is the same as Example 5.

[0039] Example 9 The difference between Example 9 and Example 8 is that the speed increasing agent in Example 8 is composed of potassium silicate and sodium N-hydroxymethylglycinate in a weight ratio of 1:1, and the rest is the same as Example 8.

[0040] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 5 is that the stabilizer is derived from the preparation of Comparative Example 1, and the rest is the same as Example 5.

[0041] Comparative Example 2 The difference between Comparative Example 2 and Example 5 is that the stabilizer is derived from the preparation of Comparative Example 2, and the rest is the same as Example 5.

[0042] Comparative Example 3 The difference between Comparative Example 3 and Example 8 is that the stabilizer is replaced by diethylene glycol butyl ether in an equal amount, and the rest is the same as Example 8.

[0043] Comparative Example 4 The difference between Comparative Example 4 and Example 8 is that the speed increasing agent is replaced by diethylene glycol butyl ether in equal amount, and the rest is the same as Example 8.

[0044] Comparative Example 5 The difference between Comparative Example 5 and Example 8 is that an equal amount of tetrahydrofurfuryl alcohol is replaced by diethylene glycol butyl ether, and the rest is the same as Example 8.

[0045] Performance testing The following is a performance test of the environmentally friendly film removal liquids prepared in Examples 1-9 and Comparative Examples 1-5: 1. Dry film removal time test Immerse the PCB board (copper-plated PCB board, circuit pattern width 0.15mm, dry film thickness 30μm, circuit board size 50.8mm*50.8mm) to be removed from the dry film in the environmentally friendly film removal solution, heat it to 55°C, and stop timing after the dry film is completely removed (the dry film removal rate is greater than 99.5% for passing), record the time for removing the dry film (unit: s), and record the test results; 2. PCB board circuit pattern removal dry film corrosion test: After removing the dry film, the PCB board is tested using AOI equipment. The standard circuit pattern is compared with the AIO scan and the number of corrosion points on the PCB board circuit pattern is calculated (unit: pieces). If the number of corrosion points is less than 5, it is qualified and the test results are recorded; 3. Long-term corrosion test of PCB circuit graphics The PCB board to be de-dried (copper-plated PCB board, circuit pattern width 0.15mm, dry film thickness 30μm, circuit board size 50.8mm*50.8mm) was immersed in a temperature of 55℃ for 10min, washed and dried, and then tested using AOI equipment. The standard circuit pattern was compared with AIO scanning and the number of corrosion points of the circuit pattern of the PCB board was calculated (unit: piece), and the test results were recorded; The following are the performance test data of the environmentally friendly film removal liquids prepared in Examples 1-9 and Comparative Examples 1-5, see Table 4 below for details.

[0046] Table 4 Performance test data of Examples 1-9 and Comparative Examples 1-5 “ / ” indicates obvious corrosion.

[0047] In combination with Examples 1-6 and Comparative Examples 1-2 and Table 4, it can be concluded that the use of the stabilizer prepared from hydroxypropyl chitosan, N-tri(hydroxymethyl)methylglycine and quaternary ammonium salt of the present application, and further optimizing the components of the quaternary ammonium salt, the quaternary ammonium salt is composed of polyquaternium-39 and organosilicon long-chain quaternary ammonium salt, can improve the film removal efficiency of the prepared environmentally friendly film removal liquid. The dry film removal time of the environmentally friendly film removal liquid prepared in Example 5 reaches 105s, and there are only 6 corrosion points, and the corrosion points after long-term corrosion testing are 13; the dry film removal time of the environmentally friendly film removal liquid prepared in Example 4 is 111s, and there are 10 corrosion points , and there are 18 corrosion points after long-term corrosion test. The dry film removal time of the environmentally friendly film removal liquid prepared in Example 1 is 113s, there are 11 corrosion points, and there are 21 corrosion points after long-term corrosion test, which shows that in Examples 1-4, polyquaternium-39 and silicone long-chain quaternary ammonium salt are not used for compounding, and the film removal time of the environmentally friendly film removal liquid prepared is increased, and the corrosion points are also increased; while in Comparative Examples 1 and Comparative Examples 2, the components of hydroxypropyl chitosan, N-tri(hydroxymethyl)methylglycine and quaternary ammonium salt are changed. Compared with Example 4, the dry film removal time is significantly improved, and the corrosion points are also significantly increased.

[0048] Combining Example 5 and Examples 7-9 with Table 4, it can be concluded that further optimizing the components of the accelerator and using potassium silicate, potassium persulfate and sodium N-hydroxymethylglycinate as accelerators can significantly improve the dry film removal efficiency of the prepared environmentally friendly film stripping solution, while also reducing the corrosion performance to the circuit pattern.

[0049] Combining Example 8 and Comparative Examples 3-5 and Table 4, it can be concluded that the use of the stabilizer, accelerator, diethylene glycol ethyl ether, hexyl glycol ether and tetrahydrofurfuryl alcohol of the present application for compounding can produce a good synergistic effect, improve the film removal efficiency of the prepared environmentally friendly film removal liquid, and reduce the corrosion performance of the circuit pattern of the PCB board. Compared with Example 8, Comparative Example 3 does not add a stabilizer, and the film removal efficiency of the prepared environmentally friendly film removal liquid is reduced, and the corrosiveness is significantly improved; Compared with Example 8, Comparative Example 4 does not add an accelerator, and the film removal efficiency of the prepared environmentally friendly film removal liquid is significantly reduced; In Comparative Example 5, tetrahydrofurfuryl alcohol is replaced with diethylene glycol ethyl ether in equal amounts, and the film removal efficiency of the prepared environmentally friendly film removal liquid is reduced.

[0050] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. An environmentally friendly film removal liquid, characterized in that: Made from the following raw materials in weight percentage: Alkaline hydroxide 2-4% Diethylene glycol butyl ether 3-5% Tetrahydrofurfuryl alcohol 3.5-5.5% Ethylene glycol hexyl ether 2-4% Speed ​​accelerator 3-5% Stabilizer 4-6% Water balance; The stabilizer is prepared from hydroxypropyl chitosan, N-tri(hydroxymethyl)methylglycine, quaternary ammonium salt and water.

2. The environmentally friendly film removal liquid according to claim 1, characterized in that: The stabilizer is prepared from the following raw materials in weight percentage: Hydroxypropyl chitosan 4-6% N-Tris(hydroxymethyl)methylglycine 2-4% Quaternary ammonium salt 8-10% Water balance.

3. An environmentally friendly film removal liquid according to claim 1 or 2, characterized in that: The stabilizer is prepared by the following steps: S1, adding hydroxypropyl chitosan and N-tris(hydroxymethyl)methylglycine to water, heating for reaction, and obtaining reactant A; S2. Add quaternary ammonium salt to reactant A, mix and stir to obtain a stabilizer.

4. The environmentally friendly film removal liquid according to claim 3, characterized in that: The reaction temperature in step S1 is 45-65° C., and the reaction time is 1-2 h.

5. The environmentally friendly film removal liquid according to claim 3, characterized in that: The quaternary ammonium salt is one or a combination of polyquaternium-7, polyquaternium-39, and organosilicon long-chain quaternary ammonium salt.

6. The environmentally friendly film removal liquid according to claim 5, characterized in that: The quaternary ammonium salt is composed of polyquaternium-39 and organosilicon long-chain quaternary ammonium salt in a weight ratio of 1:(1-2).

7. The environmentally friendly film removal liquid according to claim 1, characterized in that: The speed increasing agent is composed of potassium silicate, potassium persulfate and sodium N-hydroxymethylglycinate in a weight ratio of (1-2):1:(2-3).

8. The environmentally friendly film removal liquid according to claim 1, characterized in that: The alkaline hydroxide is one or a combination of sodium hydroxide, potassium hydroxide and barium hydroxide.

9. A method for preparing an environmentally friendly film removal solution as claimed in any one of claims 1 to 8, characterized in that: Add alkaline hydroxide and accelerator into water, stir to dissolve, add diethylene glycol butyl ether, ethylene glycol hexyl ether and tetrahydrofurfuryl alcohol, stir evenly, then add stabilizer, stir evenly to prepare environmentally friendly film removal liquid.

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