Composite cleaning agent, method for preparing the same, and use thereof

Abstract

The application relates to a composite cleaning agent and a preparation method and application thereof. The composite cleaning agent comprises, in percentage by mass, 8-16% of a persulfate, 2-5% of a chelating agent, 2-8% of an alkaline activator, 1-8% of an organic solvent, and 63-87% of water; the chelating agent comprises one or more of ethylenediaminetetraacetic acid and water-soluble salts thereof. The composite cleaning agent can quickly and completely decompose and strip various complex stains generated in a developing process through the synergistic cooperation of the persulfate, the chelating agent, the alkaline activator and the organic solvent.

Description

Technical Field

[0001] This application relates to the field of printed circuit board manufacturing technology, and in particular to composite cleaning agents, their preparation methods, and applications. Background Technology

[0002] The developing process is a crucial step in the transfer of patterns on printed circuit boards (PCBs). As the production line continues to operate, dry film residue, photoresist, grease, developer crystals, and metal ions such as copper ions etched from the PCB gradually accumulate on the inner walls of the developing tank, circulating pumps, filtration systems, and spray devices. These metal ions combine with organic contaminants to form firmly adhering complex dirt. With the accumulation of contaminants, the performance and reliability of the equipment decline, affecting not only the developing effect but also the alignment accuracy of subsequent PCB exposure and etching.

[0003] Currently, traditional tank cleaning agents have low cleaning efficiency and poor cleaning effect for complex dirt generated in the developing process. Simply increasing the cleaning temperature and the concentration of the tank cleaning agent can easily lead to tank corrosion or introduce impurities, resulting in secondary pollution. Summary of the Invention

[0004] Therefore, it is necessary to provide a composite cleaning agent with excellent removal ability for dirt generated in the development process of printed circuit boards, as well as its preparation method and application.

[0005] In a first aspect, this application provides a composite cleaning agent.

[0006] Persulfate 8%~16%,

[0007] Chelating agent 2%~5%,

[0008] Alkaline activator 2%~8%,

[0009] Organic solvents 1%~8%, and

[0010] Water content: 63%–87%;

[0011] The chelating agent includes one or more of ethylenediaminetetraacetic acid (EDTA) and water-soluble salts of EDTA.

[0012] In some embodiments, the water-soluble salt of ethylenediaminetetraacetic acid includes one or more of disodium ethylenediaminetetraacetic acid and tetrasodium ethylenediaminetetraacetic acid.

[0013] In some embodiments, the alkaline activator includes one or more of potassium hydroxide and sodium hydroxide.

[0014] In some embodiments, the organic solvent includes alcohol ether solvents.

[0015] In some embodiments, the organic solvent includes one or more of ethylene glycol monobutyl ether, propylene glycol methyl ether, and propylene glycol butyl ether.

[0016] In some embodiments, the composite cleaning agent comprises, by weight percentage, the following:

[0017] Persulfate 10%~15%,

[0018] Chelating agent 2%~5%,

[0019] Alkaline activator 4%~6%,

[0020] Organic solvents 3%~5%, and

[0021] Remaining water.

[0022] In some embodiments, the composite cleaning agent is used to clean dirt generated during the developing process.

[0023] In a second aspect, this application provides a method for preparing the aforementioned composite cleaning agent.

[0024] A method for preparing the above-mentioned composite cleaning agent includes the following steps:

[0025] A first solution is prepared by mixing water, persulfate, and an alkaline activator.

[0026] The composite cleaning agent is prepared by mixing the first solution, the chelating agent, and the organic solvent.

[0027] In a third aspect, this application provides the application of the above-described composite cleaning agent or the composite cleaning agent prepared by the above-described preparation method in cleaning developing tanks, developing tank rollers, circulating pumps, filtration systems, and spraying devices.

[0028] The aforementioned composite cleaning agent, through the synergistic effect of persulfate, chelating agents, alkaline activators, and organic solvents, utilizes multiple removal mechanisms—including the complexation of copper ions by the chelating agent, the oxidative decomposition of sulfate free radicals, the hydrolysis of hydroxide ions, and the dissolution by the organic solvent—to thoroughly and rapidly decompose and remove various complex contaminants generated during the developing process. Specifically, the chelation product formed by the chelating agent and copper ions in the complex contaminants not only inhibits the precipitation of metal hydroxides but also accelerates electron transfer and regulates the •OH / SO4 ratio through ligand-metal electron coupling. •- The ratio of free radical generation, thereby gently and continuously activating persulfate, avoids ineffective decomposition of dirt due to simultaneous chain explosion of free radicals, significantly improves free radical utilization and cleaning efficiency, and reduces the risk of corrosion to equipment. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a comparison of the cleaning effects of the composite cleaning agent in Example 1 of this application.

[0031] Figure 2 This is a comparison of the cleaning effects of the composite cleaning agent in Example 2 of this application.

[0032] Figure 3 This is a comparison of the cleaning effects of the composite cleaning agent in Example 3 of this application.

[0033] Figure 4 This is a comparison of the cleaning effects of the composite cleaning agent in Example 4 of this application.

[0034] Figure 5 This is a comparison of the cleaning effects of the composite cleaning agent in Comparative Example 1 of this application.

[0035] Figure 6 This is a comparison of the cleaning effects of the composite cleaning agent in Comparative Example 2 of this application.

[0036] Figure 7 This is a comparison of the cleaning effects of the composite cleaning agent in Comparative Example 3 of this application.

[0037] Figure 8 This is a comparison of the cleaning effects of the composite cleaning agent in Comparative Example 4 of this application. Detailed Implementation

[0038] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0039] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. In this application, "at least one" means one or more, such as one, two, or more than two. "Multiple" or "several" means at least two, such as two, three, etc.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0042] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0043] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0044] Unless otherwise specified, the viscosity parameters in this application refer to the viscosity measured at 25°C.

[0045] Unless otherwise specified, the average molecular weight of polymers used in this application refers to weight-average molecular weight.

[0046] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0047] The developing process is a crucial step in the transfer of patterns on printed circuit boards (PCBs). As the production line continues to operate, contaminants such as dry film residue, photoresist, grease, and developer crystals, as well as trace amounts of copper ions from PCB etching, gradually accumulate on the inner walls of the developing tank, circulating pumps, filtration systems, and spray devices. These metal ions combine with organic contaminants to form firmly adhering composite dirt.

[0048] Currently, most commercially available tank cleaning agents are strong acid or strong alkali types. Acidic cleaning agents rely on the acidic environment of organic or inorganic acids such as citric acid and sulfamic acid to dissolve inorganic salt scale, but have limited ability to remove organic polymers and are highly corrosive to equipment. Alkaline cleaning agents rely on strong alkalis such as potassium hydroxide and monoethanolamine to saponify grease and oil stains and hydrolyze some organic polymers. Similarly, they have insufficient penetration ability for polymers, and high concentrations can affect the lifespan of plastic parts and cause severe corrosion to equipment.

[0049] Based on this, the first aspect of this application provides a composite cleaning agent that has excellent removal ability for dirt generated during the development process of printed circuit boards.

[0050] For example, by weight percentage, a compound cleaning agent includes:

[0051] Persulfate 8%~16%,

[0052] Chelating agent 2%~5%,

[0053] Alkaline activator 2%~8%,

[0054] Organic solvents 1%~8%, and

[0055] Water content: 63%–87%;

[0056] Chelating agents include one or more of ethylenediaminetetraacetic acid and its water-soluble salts.

[0057] The aforementioned composite cleaning agent, through the synergistic effect of persulfate, chelating agents, alkaline activators, and organic solvents, utilizes multiple removal mechanisms—including the complexation of copper ions by the chelating agent, the oxidative decomposition of sulfate free radicals, the hydrolysis of hydroxide ions, and the dissolution by organic solvents—to rapidly and thoroughly decompose and remove various complex contaminants generated during the developing process. Specifically, the chelation product formed between the chelating agent and copper ions in the developing tank gently and continuously activates the persulfate, preventing ineffective decomposition due to simultaneous chain reactions of free radicals. This significantly improves free radical utilization and cleaning efficiency while reducing the risk of equipment corrosion. Furthermore, the composite cleaning agent can be used to clean materials such as stainless steel, polypropylene, and polyvinyl chloride, and is perfectly compatible with materials commonly used in PCB production lines, such as stainless steel, PP, and PVC, with a lower corrosion risk than traditional strong acid and strong alkali cleaning agents.

[0058] In some embodiments, the composite cleaning agent is used to clean contaminants generated during the developing process. This composite cleaning agent cleverly utilizes the copper ions contained in the contaminants from the developing process, thereby achieving excellent cleaning capabilities. Specifically, under alkaline conditions, the chelating agent can complex free copper ions in the developing tank to form [(II)Cu(EDTA)]. 2- Water-soluble metal chelates can effectively inhibit the precipitation of metal hydroxides, accelerate electron transfer through ligand-metal electron coupling, and regulate the •OH / SO4 ratio. •- The proportion of free radicals generated significantly improves the activation efficiency of persulfate.

[0059] Optionally, the persulfate content in the composite cleaning agent, by mass percentage, can be, but is not limited to, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, or other values ​​within the range of 8% to 16%. Persulfate, when activated under alkaline conditions, generates free radicals, which serve as the main component for oxidizing and decomposing dirt.

[0060] Optionally, the content of the chelating agent in the composite cleaning agent, by mass percentage, can be, but is not limited to, 2%, 3%, 4%, 5%, or other values ​​within the range of 2% to 5%. In this embodiment, the chelating agent includes ethylenediaminetetraacetic acid and its water-soluble salt, used to complex copper ions in the tank and promote the continuous release of persulfate. The content of the chelating agent should not be too high, otherwise the cleaning efficiency will not be significantly improved, and the system stability may be affected by excessive chelating components.

[0061] Optionally, the content of alkaline activator in the composite cleaning agent, by mass percentage, can be, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or other values ​​within the range of 2% to 8%. The alkaline activator is used to provide and control the alkaline environment required for cleaning, promoting the generation of free radicals and hydrolyzing organic pollutants. The content of alkaline activator should not be too high, otherwise it may lead to free radical quenching, inhibit the reaction cycle, and easily cause corrosion.

[0062] Optionally, the content of organic solvent in the composite cleaning agent, by mass percentage, can be, but is not limited to, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or other values ​​within the range of 1% to 8%. Organic solvents are used to assist in penetration and dissolution of grease and some organic polymers, thereby more efficiently removing dirt.

[0063] Optionally, the water content in the composite cleaning agent, by mass percentage, can be, but is not limited to, 63%, 65%, 67%, 69%, 71%, 73%, 75%, 77%, 79%, 81%, 83%, 85%, 87%, or other values ​​within the range of 63% to 87%.

[0064] In some of these implementations, the water includes deionized water.

[0065] In some embodiments, the chelating agent includes disodium ethylenediaminetetraacetate.

[0066] In some embodiments, the persulfate includes one or more of sodium persulfate, potassium persulfate, and ammonium persulfate.

[0067] In some embodiments, the alkaline activator includes one or more of potassium hydroxide and sodium hydroxide.

[0068] In some embodiments, the organic solvent includes alcohol ether solvents.

[0069] In some embodiments, the organic solvent includes one or more of ethylene glycol monobutyl ether, propylene glycol methyl ether, and propylene glycol butyl ether. These solvents possess excellent penetrating and dissolving capabilities, and have moderate evaporation rates, which helps maintain the effective concentration during the cleaning process.

[0070] In some embodiments, the composition of the composite cleaning agent, by mass percentage, is as follows:

[0071] Persulfate 10%~15%,

[0072] Chelating agent 2%~5%,

[0073] Alkaline activator 4%~6%,

[0074] Organic solvents 3%~5%, and

[0075] Remaining water.

[0076] Studies have shown that maintaining the above-mentioned component content can effectively remove dirt generated during the development process of printed circuit boards. Furthermore, the composite cleaning agent does not introduce new metal ions; the metal ion resources come from the scale layer itself, eliminating the need for external catalysts such as iron and manganese. This reduces the types and total amount of metals in the cleaning waste liquid from the source, effectively avoiding secondary pollution caused by the precipitation of iron ions in an alkaline working environment.

[0077] In a second aspect, this application provides a method for preparing the aforementioned composite cleaning agent.

[0078] For example, a method for preparing a composite cleaning agent includes the following steps:

[0079] A first solution is prepared by mixing water, persulfate, and an alkaline activator.

[0080] The first solution, chelating agent, and organic solvent are mixed to form a composite cleaning agent.

[0081] In some embodiments, the step of preparing the first solution includes: adding water to a reaction vessel, adding persulfate to the reaction vessel while stirring at a speed of 400 rpm to 600 rpm, stirring until completely dissolved, adding an alkaline activator, stirring until completely dissolved, and obtaining a clear first solution.

[0082] In some embodiments, the first solution, chelating agent, and organic solvent are continuously mixed at a stirring speed of 400 rpm to 600 rpm for 15 min to 60 min to form a composite cleaning agent.

[0083] In a third aspect, this application provides the application of the above-described composite cleaning agent or the composite cleaning agent prepared by the above-described preparation method in cleaning developing tanks, developing tank rollers, circulating pumps, filtration systems, and spraying devices.

[0084] The present application will be further described in detail below with reference to specific embodiments.

[0085] Unless otherwise specified, the raw materials used in the following specific embodiments and comparative examples are all commercially available products; the instruments used are all commercially available products; and the processes used are all conventionally selected by those skilled in the art unless otherwise specified.

[0086] Example 1

[0087] This embodiment provides a composite cleaning agent.

[0088] The composition of the composite cleaning agent by mass percentage is as follows: 10% sodium persulfate, 3% disodium ethylenediaminetetraacetate, 5% sodium hydroxide, 3% ethylene glycol monobutyl ether, and the balance being water.

[0089] The preparation method of the composite cleaning agent is as follows:

[0090] Water was added to the reactor, and persulfate was added to the reactor while stirring at 500 rpm. The mixture was stirred until completely dissolved. An alkaline activator was added and stirred until completely dissolved. The stirring was continued, and the chelating agent and organic solvent were added to the reactor in sequence. The mixture was stirred for another 25 minutes to obtain the composite cleaning agent.

[0091] Example 2

[0092] This embodiment provides a composite cleaning agent.

[0093] The composition of the composite cleaning agent by mass percentage is as follows: 12% sodium persulfate, 3% disodium ethylenediaminetetraacetate, 5% sodium hydroxide, 3% ethylene glycol monobutyl ether, and the balance being water.

[0094] Example 3

[0095] This embodiment provides a composite cleaning agent.

[0096] The composition of the composite cleaning agent, by mass percentage, is as follows:

[0097] Sodium persulfate 15%, disodium ethylenediaminetetraacetate 3%, sodium hydroxide 5%, ethylene glycol monobutyl ether 3%, and the balance water.

[0098] Example 4

[0099] This embodiment provides a composite cleaning agent.

[0100] The composition of the composite cleaning agent, by mass percentage, is as follows:

[0101] Sodium persulfate 15%, ethylenediaminetetraacetic acid 3%, sodium hydroxide 5%, ethylene glycol monobutyl ether 3%, and the balance water.

[0102] Comparative Example 1

[0103] This comparative example provides a composite cleaning agent.

[0104] The composition of the composite cleaning agent, by mass percentage, is as follows:

[0105] Disodium ethylenediaminetetraacetate 3%, sodium hydroxide 5%, ethylene glycol monobutyl ether 3%, and the balance water.

[0106] Comparative Example 2

[0107] This comparative example provides a composite cleaning agent.

[0108] The composition of the composite cleaning agent, by mass percentage, is as follows:

[0109] Sodium persulfate 15%, sodium hydroxide 5%, ethylene glycol monobutyl ether 3%, and the balance water.

[0110] Comparative Example 3

[0111] This comparative example provides a composite cleaning agent.

[0112] The composition of the composite cleaning agent, by mass percentage, is as follows:

[0113] Sodium persulfate 12%, disodium ethylenediaminetetraacetate 3%, sodium hydroxide 5%, and the remainder water.

[0114] Comparative Example 4

[0115] This comparative example provides a composite cleaning agent.

[0116] The composition of the composite cleaning agent, by mass percentage, is as follows:

[0117] The composition of the composite cleaning agent by mass percentage is as follows: 10% sodium persulfate, 5% disodium ethylenediaminetetraacetate, 25% sodium hydroxide, 3% ethylene glycol monobutyl ether, and the balance being water.

[0118] Test case

[0119] Prepare multiple rollers for developing tanks that have been used for a long time, and test the cleaning effect of the composite cleaning agent on the rollers in the examples and comparative examples in the following manner:

[0120] A composite cleaning agent was placed in a clean container, the temperature was raised to 45℃, the roller to be cleaned was added, and it was soaked at a constant temperature for 1 hour. Afterwards, it was removed and rinsed with water to remove any residual composite cleaning agent, resulting in a cleaned roller. The test results are shown in Table 1. Figures 1-4 The cleaning effects of the composite cleaning agents corresponding to Examples 1-4 are compared sequentially. Figures 5-8 The cleaning effects of compound cleaning agents with ratios of 1 to 4 were compared.

[0121] Table 1. Cleaning effect of the composite cleaning agents in the examples and comparative examples.

[0122]

[0123] Based on the cleaning results of Examples 1-4, it is evident that within the concentration range specified in this technical document, this solution effectively removes complex contaminants from PCB developing tanks, efficiently removing all tank scale from the rollers even with only a short immersion time. The main difference between Comparative Example 1 and Example 1 is the absence of sodium persulfate. The cleaning results from both examples show that the cleaning effect is poor without the key oxidizing component, sodium persulfate. The main difference between Comparative Example 2 and Example 1 is the absence of disodium ethylenediaminetetraacetate. The cleaning results from both examples show that the cleaning efficiency of the tank cleaner decreases without a chelating agent, confirming the beneficial effect of the chelating agent on the cleaning effect. The main difference between Comparative Example 3 and Example 1 is the absence of organic solvent. The cleaning results from both examples show that the cleaning efficiency of the tank cleaner decreases without an organic solvent, confirming the beneficial effect of the organic solvent on the cleaning effect. The main difference between Comparative Example 4 and Example 1 is the excessive amount of sodium hydroxide. The cleaning results from both examples show that excessive sodium hydroxide inhibits the reaction cycle, leading to a decrease in the cleaning effect. It should also be noted that although Example 4 could not completely remove the dirt within 1 hour, if the cleaning time is extended to 2 hours, the dirt can still be completely removed.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A composite cleaning agent, characterized in that, In terms of mass percentage, including: Persulfate 8%~16%, Chelating agent 2%~5%, Alkaline activator 2%~8%, Organic solvents 1%~8%, and Water content: 63%–87%; The chelating agent includes one or more of ethylenediaminetetraacetic acid (EDTA) and water-soluble salts of EDTA.

2. The composite cleaning agent according to claim 1, characterized in that, The water-soluble salts of ethylenediaminetetraacetic acid include one or more of disodium ethylenediaminetetraacetic acid and tetrasodium ethylenediaminetetraacetic acid.

3. The composite cleaning agent according to claim 1, characterized in that, The persulfate includes one or more of sodium persulfate, potassium persulfate, and ammonium persulfate.

4. The composite cleaning agent according to claim 1, characterized in that, The alkaline activator includes one or more of potassium hydroxide and sodium hydroxide.

5. The composite cleaning agent according to claim 1, characterized in that, The organic solvents include alcohol ether solvents.

6. The composite cleaning agent according to claim 5, characterized in that, The organic solvent includes one or more of ethylene glycol monobutyl ether, propylene glycol methyl ether, and propylene glycol butyl ether.

7. The composite cleaning agent according to any one of claims 1 to 6, characterized in that, The composition of the composite cleaning agent, by mass percentage, is as follows: Persulfate 10%~15%, Chelating agent 2%~5%, Alkaline activator 4%~6%, Organic solvents 3%~5%, and Remaining water.

8. The composite cleaning agent according to any one of claims 1 to 6, characterized in that, The composite cleaning agent is used to clean dirt generated during the developing process.

9. A method for preparing the composite cleaning agent according to any one of claims 1 to 8, characterized in that, Includes the following steps: A first solution is prepared by mixing water, persulfate, and an alkaline activator. The composite cleaning agent is prepared by mixing the first solution, the chelating agent, and the organic solvent.

10. The application of a composite cleaning agent according to any one of claims 1 to 8 or a composite cleaning agent prepared by the preparation method according to claim 9 in cleaning a developing tank, developing tank rollers, a circulating pump, a filtration system, and a spraying device.

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