Water-washable flux compositions and use thereof

Abstract

This application relates to a water-washable flux composition and its application. The water-washable flux composition comprises, by weight percentage: 2%–10% organic acid, 5%–30% amine corrosion inhibitor, 30%–50% alcohol ether compound, 1%–15% surfactant, and 30%–50% solvent. The water-washable flux composition is easy to clean with water after soldering, and exhibits no corrosion and high soldering stability.

Description

Technical Field

[0001] This application relates to the field of flux technology, and in particular to a water-washable flux composition and its application. Background Technology

[0002] In recent years, the electronics manufacturing industry has been transitioning from lead-containing solder to lead-free solder. Therefore, finding suitable, easy-to-clean, and high-temperature-resistant fluxes has become a research focus for scientists. Meanwhile, as surface mount technology for electronic circuits develops towards high-end, precision, and advanced fields, it not only demands energy-saving and environmentally friendly manufacturing processes but also requires clean, corrosion-free soldering with high soldering stability.

[0003] Currently, the main types of fluxes on the market are rosin-based fluxes, no-clean fluxes, and water-washable fluxes. While rosin-based fluxes offer good solderability and low cost, they leave high levels of residue after soldering, and this residue contains halide ions, making it highly corrosive and gradually leading to decreased electrical insulation performance and short circuits. No-clean fluxes, due to their advantages of requiring no post-soldering cleaning and simple processing, are becoming the mainstream direction in flux development. However, their application range is narrower; for example, white residue may appear when soldering PCBs. During product assembly, these residues may cause product defects and pose quality risks. Therefore, water-washable fluxes, which allow for post-soldering residue cleaning, are being prioritized for development. Summary of the Invention

[0004] Based on this, this application provides a water-washable flux composition that is easy to clean with water after welding, has no corrosion, and has high welding stability, as well as its application.

[0005] A first aspect of this application provides a water-washable flux composition, comprising, by weight percentage, the following components:

[0006] Organic acids 2%~10%, amine corrosion inhibitors 5%~30%, alcohol ether compounds 30%~50%, surfactants 1%~15%, and solvents 30%~50%.

[0007] In some embodiments, the water-washable flux composition has at least one of the following characteristics:

[0008] (1) The organic acids include one or more of citric acid, malic acid, glutaric acid, diethylene glycol, thionyl diacetic acid, tartaric acid, trimeric acid, itaconic acid, azelaic acid, glycolic acid, phenyl succinic acid, malonic acid, succinic acid, adipic acid, mercaptoacetic acid and salicylic acid;

[0009] (2) The amine corrosion inhibitors include one or more of glutamine, monoethanolamine, diethanolamine, triethanolamine, dibutylamine, o-methoxyaniline, tetrahydroxypropylethylenediamine, triisopropanolamine, ethylenediamine, polyoxyalkylene alkylamine, isopropylamine and butylamine;

[0010] (3) The alcohol ether compounds include one or more of dipropylene glycol butyl ether, diethylene glycol butyl ether, tripropylene glycol butyl ether, ethylene glycol butyl ether, triethylene glycol propyl ether, phenyl crown ether, 18-crown-6-ether, propylene glycol butyl ether and diethylene glycol propyl ether;

[0011] (4) The surfactant includes one or more of alkyl glycosides, methyl glucosides, n-octyl glucosides, decyl glucosides, lauryl glucosides, alkylphenol polyoxyethylene ethers, C12~C18 fatty alcohol polyoxyethylene ethers, bisphenol A polyoxyethylene ethers, and EO / PO block polyethers.

[0012] (5) The solvent includes one or more polymeric alcohol compounds and nonpolymeric alcohol compounds with a molecular weight of less than or equal to 1000.

[0013] In some embodiments, the pH of the water-washable flux composition is 4 to 7.

[0014] In some embodiments, the mass ratio of the organic acid to the amine corrosion inhibitor is 1:(0.5-3.5).

[0015] In some embodiments, the organic acid is selected from the group consisting of citric acid, malic acid and trimeric acid, malic acid and tartaric acid, glycolic acid, thionyl diacetic acid, malic acid, malonic acid, and adipic acid; optionally, the organic acid is selected from the group consisting of malic acid, glycolic acid, thionyl diacetic acid, malonic acid, and adipic acid.

[0016] In some embodiments, the amine corrosion inhibitor is selected from one or more of triethanolamine, ethylenediamine, tetrahydroxypropyl ethylenediamine, triisopropanolamine, dibutylamine, and diethanolamine; optionally, the amine corrosion inhibitor is selected from one or more of ethylenediamine, triisopropanolamine, dibutylamine, triisopropanolamine, and diethanolamine.

[0017] In some embodiments, the alcohol ether compound is selected from the group consisting of dipropylene glycol butyl ether, or ethylene glycol butyl ether and propylene glycol butyl ether, or phenyl crown ether, or diethylene glycol propyl ether, or diethylene glycol butyl ether; optionally, the alcohol ether compound is selected from the group consisting of ethylene glycol butyl ether and propylene glycol butyl ether, or diethylene glycol propyl ether, or diethylene glycol butyl ether.

[0018] In some embodiments, the surfactant is selected from one or more of isooctylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, alkyl glycoside, octylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether AEO-3; optionally, the surfactant is selected from one or more of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether AEO-3, and alkyl glycoside.

[0019] In some embodiments, the solvent is selected from PEG800, or propylene glycol, or glycerol, or ethylene glycol, or glycerin, or the group consisting of PEG600 and ethylene glycol, or one or more of PEG600; optionally, the solvent is selected from propylene glycol, or ethylene glycol, or glycerin, or the group consisting of PEG600 and ethylene glycol, or PEG600.

[0020] In some embodiments, the water-washable flux composition comprises, by weight percentage, the following components:

[0021] Citric acid 2%~5%, triethanolamine 5%~10%, dipropylene glycol butyl ether 40%~50%, isooctylphenol polyoxyethylene ether 1%~5%, and PEG800 40%~50%.

[0022] In some embodiments, the water-washable flux composition comprises, by weight percentage, the following components:

[0023] Malic acid and triglycerides 2%~6%, ethylenediamine 5%~15%, ethylene glycol butyl ether and propylene glycol butyl ether 40%~50%, nonylphenol polyoxyethylene ether 5%~15%, and propylene glycol 30%~40%.

[0024] In some embodiments, the water-washable flux composition comprises, by weight percentage, the following components:

[0025] Malic acid and tartaric acid 4%~8%, tetrahydroxypropyl ethylenediamine 5%~15%, phenyl crown ether 30%~40%, alkyl glycoside 10%~15%, and glycerol 35%~45%.

[0026] In some embodiments, the water-washable flux composition comprises, by weight percentage, the following components:

[0027] Glycolic acid 5%~10%, triisopropanolamine 15%~25%, diethylene glycol propyl ether 30%~40%, octylphenol polyoxyethylene ether 5%~15%, and ethylene glycol 30%~40%.

[0028] In some embodiments, the water-washable flux composition comprises, by weight percentage, the following components:

[0029] The ingredients include 2%~8% thionyl diacetic acid, 10%~20% dibutylamine, 35%~45% diethylene glycol butyl ether and propylene glycol butyl ether, 1%~5% fatty alcohol polyoxyethylene ether AEO-3, and 40%~50% glycerol.

[0030] In some embodiments, the water-washable flux composition comprises, by weight percentage, the following components:

[0031] Malic acid 2%~8%, triisopropanolamine 10%~20%, diethylene glycol butyl ether 30%~50%, nonylphenol polyoxyethylene ether 1%~10%, and PEG600 and ethylene glycol 40%~50%.

[0032] In some embodiments, the water-washable flux composition comprises, by weight percentage, the following components:

[0033] Malonic acid and adipic acid 3%~7%, diethanolamine 5%~10%, diethylene glycol propyl ether 35%~45%, alkyl glycosides 2%~10%, and PEG600 35%~45%.

[0034] A second aspect of this application provides the use of the water-washable flux composition described in the first aspect in the surface assembly of electronic circuits.

[0035] The water-washable flux composition provided in this application uses organic acids and amine corrosion inhibitors as activators to remove oxides from the soldering surface. It is supplemented with alcohol ether compounds, surfactants, and solvents to form a uniform and stable flux system. In particular, the reasonable adjustment of the mass percentage of each component makes this water-washable flux composition highly wettable for lead-free solder, enhancing the solderability of lead-free solder, resulting in full solder joints after soldering, fewer voids after reflow, good uniformity, and stable connections. Simultaneously, the composition is halogen-free, has low corrosiveness, low residue, and is easy to wash with water, making it an environmentally friendly flux, especially suitable for soldering processes in the surface assembly of electronic circuits. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the water washing performance test in Embodiment 2 of this application. Detailed Implementation

[0037] The following detailed description, in conjunction with specific embodiments, illustrates the water-washable flux composition and its application of this application. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0038] 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 this application.

[0039] In this article, "one or more" refers to any one, two or more of the listed items.

[0040] In this application, terms such as "first aspect" and "second aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first" and "second" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0041] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0042] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include 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 merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0043] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0044] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0045] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows for temperature fluctuations within the precision range controlled by the instrument.

[0046] In this application, room temperature generally refers to 4℃~30℃, and preferably 20±5℃.

[0047] Some examples of this application provide a water-washable flux composition comprising, by weight percentage, the following components:

[0048] Organic acids 2%~10%, amine corrosion inhibitors 5%~30%, alcohol ether compounds 30%~50%, surfactants 1%~15%, and solvents 30%~50%.

[0049] Specifically, the mass percentage of the organic acid includes, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any range between the foregoing. Furthermore, properly controlling the mass percentage of the organic acid can improve flux activity, enhance oxide removal capabilities, and reduce corrosiveness.

[0050] Specifically, the mass percentage of the amine corrosion inhibitor includes, but is not limited to: 5%, 8%, 10%, 12%, 15%, 17%, 20%, 22%, 25%, 27%, 30%, or any two of the foregoing.

[0051] Specifically, the mass percentage of the alcohol ether compound includes, but is not limited to: 30%, 33%, 35%, 38%, 41%, 43%, 45%, 47%, 50%, or any range between the two for the foregoing.

[0052] Specifically, the mass percentage of the surfactant includes, but is not limited to: 1%, 2%, 5%, 8%, 10%, 12%, 15%, or any two of the foregoing.

[0053] Specifically, the mass percentage of the solvent includes, but is not limited to: 30%, 32%, 35%, 37%, 41%, 43%, 45%, 46%, 47%, 50%, or any range between the two for the foregoing.

[0054] In some of these examples, the organic acid is a water-soluble acid. Further, the organic acid includes one or more of citric acid, malic acid, glutaric acid, diethylene glycol, thionyl diacetic acid, tartaric acid, trimeric acid, itaconic acid, azelaic acid, glycolic acid, phenylsuccinic acid, malonic acid, succinic acid, adipic acid, mercaptoacetic acid, and salicylic acid.

[0055] Without limitation, when using a single organic acid, the organic acid can be malic acid, citric acid, diethylene glycol, glycolic acid, or thionyl diacetic acid, with a mass percentage of 2% to 8%. When using a combination of two or more organic acids, one or more of malic acid, glycolic acid, and diethylene glycol can be used, combined with one or more of citric acid, trimeric acid, glycolic acid, glutaric acid, tartaric acid, azelaic acid, malonic acid, and thionyl diacetic acid, with each organic acid having a mass percentage of 1% to 4%. The combination of two or more organic acids is beneficial for cleaning metal oxides during welding. Since different organic acids have different cleaning abilities for metal ions, compounding can enhance the cleaning ability. Furthermore, since different organic acids exhibit varying degrees of acidity, using multiple acids in combination is more conducive to controlling the overall acidity of the formulation, thereby fully utilizing the cleaning effect on metal oxides.

[0056] In some examples, the amine corrosion inhibitor includes one or more of glutamine, monoethanolamine, diethanolamine, triethanolamine, dibutylamine, o-methoxyaniline, tetrahydroxypropylethylenediamine, triisopropanolamine, ethylenediamine, polyoxyalkylene alkylamine, isopropylamine, and butylamine. Further, the amine corrosion inhibitor includes one or more of glutamine, ethylenediamine, triisopropanolamine, tetrahydroxypropylethylenediamine, and dibutylamine.

[0057] Without limitation, the combined use of the organic acid and amine corrosion inhibitor may include one or more of malic acid, citric acid, diethylene glycol, glycolic acid and thionyl diacetic acid, and one or more of glutamine, ethylenediamine, triisopropanolamine, tetrahydroxypropyl ethylenediamine and dibutylamine.

[0058] Furthermore, the pH of the water-washable flux composition is 4-7. This pH can be adjusted by changing the mass ratio of the organic acid and the amine corrosion inhibitor. This makes the system weakly acidic, thereby significantly reducing the corrosive effect of the flux on the solder pads and solder ball metal during use, and improving the ability to dissolve and clean metal oxides. Specifically, the pH of the water-washable flux composition includes, but is not limited to: 4, 4.5, 5, 5.5, 6, 6.5, 7, or any range between the foregoing.

[0059] In some examples, the mass ratio of the organic acid to the amine corrosion inhibitor is 1:(0.5-3.5). Specifically, the mass ratio of the organic acid to the amine corrosion inhibitor includes, but is not limited to: 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, or any range between the two for the foregoing.

[0060] In some examples, the alcohol ether compounds include one or more of dipropylene glycol butyl ether, diethylene glycol butyl ether, tripropylene glycol butyl ether, ethylene glycol butyl ether, triethylene glycol propyl ether, phenyl crown ether, 18-crown-6-ether, propylene glycol butyl ether, and diethylene glycol propyl ether. This enhances the solubility between components, adjusts the viscosity of the solder resist system, neutralizes organic acids (resulting in a pH of 4-7 after neutralization), and adjusts the surface tension between the flux and the substrate. Further, the alcohol ether compounds include one or more of ethylene glycol butyl ether, tripropylene glycol butyl ether, and ethylene glycol butyl ether.

[0061] In some examples, the surfactant includes one or more of alkyl glycosides (e.g., APG0810, APG0814, APG1214, APG1218), methyl glucoside, n-octyl glucoside, decyl glucoside, lauryl glucoside, alkylphenol polyoxyethylene ethers (e.g., octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, isooctylphenol polyoxyethylene ether, dodecyl polyoxyethylene ether), C12-C18 fatty alcohol polyoxyethylene ethers, bisphenol A polyoxyethylene ethers, and EO / PO block polyethers. This reduces the surface tension between the system and the substrate, increasing the wetting properties between the flux and the substrate. It is important to note that the degree of wetting needs to be properly controlled; excessive wetting of the flux and substrate may lead to bridging during printing. Further, the surfactant includes octylphenol polyoxyethylene ether and / or isooctylphenol polyoxyethylene ether.

[0062] In some examples, the solvent comprises one or more of polymerizable alcohols and non-polymerizable alcohols with a molecular weight of 1000 or less. This effectively adjusts the viscosity of the system, ranging from approximately 20 Pa·s to 150 Pa·s, while the solvent provides a suitable dissolution environment for each component, resulting in a homogeneous and stable system and reducing the possibility of stratification during prolonged storage. Without limitation, the polymerizable alcohols with a molecular weight of 1000 or less can be one or more of polyethylene glycol 400 (PEG400), polyethylene glycol 600 (PEG600), and polyethylene glycol 800 (PEG800); the non-polymerizable alcohols can be one or more of anhydrous methanol, anhydrous ethanol, ethylene glycol, propylene glycol, glycerol, and glycerol.

[0063] In some of these examples, the organic acid is selected from the group consisting of citric acid, malic acid and trimeric acid, malic acid and tartaric acid, glycolic acid, thionyl diacetic acid, malic acid, malonic acid, and adipic acid; alternatively, the organic acid is selected from the group consisting of malic acid, glycolic acid, thionyl diacetic acid, malonic acid, and adipic acid.

[0064] In some examples, the amine corrosion inhibitor is selected from one or more of triethanolamine, ethylenediamine, tetrahydroxypropyl ethylenediamine, triisopropanolamine, dibutylamine, and diethanolamine; optionally, the amine corrosion inhibitor is selected from one or more of ethylenediamine, triisopropanolamine, dibutylamine, triisopropanolamine, and diethanolamine.

[0065] In some examples, the alcohol ether compound is selected from the group consisting of dipropylene glycol butyl ether, or ethylene glycol butyl ether and propylene glycol butyl ether, or phenyl crown ether, or diethylene glycol propyl ether, or diethylene glycol butyl ether; optionally, the alcohol ether compound is selected from the group consisting of ethylene glycol butyl ether and propylene glycol butyl ether, or diethylene glycol propyl ether, or diethylene glycol butyl ether.

[0066] In some examples, the surfactant is selected from one or more of isooctylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, alkyl glycoside, octylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether AEO-3; optionally, the surfactant is selected from one or more of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether AEO-3, and alkyl glycoside.

[0067] In some examples, the solvent is selected from PEG800, or propylene glycol, or glycerol, or ethylene glycol, or glycerin, or the group consisting of PEG600 and ethylene glycol, or one or more of PEG600; optionally, the solvent is selected from propylene glycol, or ethylene glycol, or glycerin, or the group consisting of PEG600 and ethylene glycol, or PEG600.

[0068] In some of these examples, the water-washable flux composition comprises, by weight percentage, the following components:

[0069] Citric acid 2%~5%, triethanolamine 5%~10%, dipropylene glycol butyl ether 40%~50%, isooctylphenol polyoxyethylene ether 1%~5%, and PEG800 40%~50%.

[0070] Specifically, the mass percentage of citric acid includes, but is not limited to: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any range between the two mentioned above.

[0071] Specifically, the mass percentage of triethanolamine includes, but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, or any range between the two mentioned above.

[0072] Specifically, the mass percentage of dipropylene glycol butyl ether includes, but is not limited to: 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any range between the two for the foregoing.

[0073] Specifically, the mass percentage of isooctylphenol polyoxyethylene ether includes, but is not limited to: 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or any range between the two mentioned above.

[0074] Specifically, the mass percentage of PEG800 includes, but is not limited to: 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any range between the two for the foregoing.

[0075] In some of these examples, the water-washable flux composition comprises, by weight percentage, the following components:

[0076] Malic acid and triglycerides 2%~6%, ethylenediamine 5%~15%, ethylene glycol butyl ether and propylene glycol butyl ether 40%~50%, nonylphenol polyoxyethylene ether 5%~15%, and propylene glycol 30%~40%.

[0077] Specifically, the total mass percentage of malic acid and trimeric acid includes, but is not limited to, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, or any range between the foregoing. Further, the mass ratio of malic acid to trimeric acid is 1:(0.5~1.5).

[0078] Specifically, the mass percentage of ethylenediamine includes, but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or any range between the two mentioned above.

[0079] Specifically, the total mass percentage of ethylene glycol butyl ether and propylene glycol butyl ether includes, but is not limited to, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any range between the foregoing. Further, the mass ratio of ethylene glycol butyl ether to propylene glycol butyl ether is (10~15):1.

[0080] Specifically, the mass percentage of nonylphenol polyoxyethylene ether includes, but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or any range between the two mentioned above.

[0081] Specifically, the mass percentage of propylene glycol includes, but is not limited to: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or any range between the two mentioned above.

[0082] In some of these examples, the water-washable flux composition comprises, by weight percentage, the following components:

[0083] Malic acid and tartaric acid 4%~8%, tetrahydroxypropyl ethylenediamine 5%~15%, phenyl crown ether 30%~40%, alkyl glycoside 10%~15%, and glycerol 35%~45%.

[0084] Specifically, the total mass percentage of malic acid and tartaric acid includes, but is not limited to, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, or any range between the foregoing. Further, the mass ratio of malic acid to tartaric acid is 1:(0.5~1.5).

[0085] Specifically, the mass percentage of tetrahydroxypropylethylenediamine includes, but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or any range between the two mentioned above.

[0086] Specifically, the mass percentage of phenyl crown ether includes, but is not limited to: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or any range between the two for the foregoing.

[0087] Specifically, the mass percentage of alkyl glycosides includes, but is not limited to: 10%, 11%, 12%, 13%, 14%, 15%, or any range between the two mentioned above.

[0088] Specifically, the mass percentage of glycerol includes, but is not limited to: 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, or any range between the two mentioned above.

[0089] In some of these examples, the water-washable flux composition comprises, by weight percentage, the following components:

[0090] Glycolic acid 5%~10%, triisopropanolamine 15%~25%, diethylene glycol propyl ether 30%~40%, octylphenol polyoxyethylene ether 5%~15%, and ethylene glycol 30%~40%.

[0091] Specifically, the mass percentage of glycolic acid includes, but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, or any range between the two mentioned above.

[0092] Specifically, the mass percentage of triisopropanolamine includes, but is not limited to: 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, or any two of the foregoing.

[0093] Specifically, the mass percentage of diethylene glycol propyl ether includes, but is not limited to: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or any range between the two mentioned above.

[0094] Specifically, the mass percentage of octylphenol polyoxyethylene ether includes, but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or any range between the two mentioned above.

[0095] Specifically, the mass percentage of ethylene glycol includes, but is not limited to: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or any range between the two mentioned above.

[0096] In some of these examples, the water-washable flux composition comprises, by weight percentage, the following components:

[0097] The ingredients include 2%~8% thionyl diacetic acid, 10%~20% dibutylamine, 35%~45% diethylene glycol butyl ether and propylene glycol butyl ether, 1%~5% fatty alcohol polyoxyethylene ether AEO-3, and 40%~50% glycerol.

[0098] Specifically, the mass percentage of thionyl diacetic acid includes, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or any range between the two mentioned above.

[0099] Specifically, the mass percentage of dibutylamine includes, but is not limited to: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any range between the two for the foregoing.

[0100] Specifically, the total mass percentage of diethylene glycol butyl ether and propylene glycol butyl ether includes, but is not limited to, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, or any range between the foregoing. Further, the mass ratio of diethylene glycol butyl ether to propylene glycol butyl ether is (3~8):1.

[0101] Specifically, the mass percentage of fatty alcohol polyoxyethylene ether AEO-3 includes, but is not limited to, 1%, 2%, 3%, 4%, 5%, or any range between the two mentioned above.

[0102] Specifically, the mass percentage of glycerin includes, but is not limited to: 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any range between the two for the foregoing.

[0103] In some of these examples, the water-washable flux composition comprises, by weight percentage, the following components:

[0104] Malic acid 2%~8%, triisopropanolamine 10%~20%, diethylene glycol butyl ether 30%~50%, nonylphenol polyoxyethylene ether 1%~10%, and PEG600 and ethylene glycol 40%~50%.

[0105] Specifically, the mass percentage of malic acid includes, but is not limited to: 2%, 3%, 4%, 5%, 6%, 7%, 8%, or any range between the two mentioned above.

[0106] Specifically, the mass percentage of triisopropanolamine includes, but is not limited to: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any range between the two mentioned above.

[0107] Specifically, the mass percentage of diethylene glycol butyl ether includes, but is not limited to: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any range between the two for the foregoing.

[0108] Specifically, the mass percentage of nonylphenol polyoxyethylene ether includes, but is not limited to: 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any range between the two mentioned above.

[0109] Specifically, the total mass percentage of PEG600 and ethylene glycol includes, but is not limited to, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, or any range between the foregoing. Further, the mass ratio of PEG600 to ethylene glycol is (2~7):1.

[0110] In some of these examples, the water-washable flux composition comprises, by weight percentage, the following components:

[0111] Malonic acid and adipic acid 3%~7%, diethanolamine 5%~10%, diethylene glycol propyl ether 35%~45%, alkyl glycosides 2%~10%, and PEG600 35%~45%.

[0112] Specifically, the total mass percentage of malonic acid and adipic acid includes, but is not limited to, 3%, 4%, 5%, 6%, 7%, or any range between the two. Further, the mass ratio of malonic acid to adipic acid is 1:(1~2).

[0113] Specifically, the mass percentage of diethanolamine includes, but is not limited to: 5%, 6%, 7%, 8%, 9%, 10%, or any range between the two mentioned above.

[0114] Specifically, the mass percentage of diethylene glycol propyl ether includes, but is not limited to: 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, or any range between the two mentioned above.

[0115] Specifically, the mass percentage of alkyl glycosides includes, but is not limited to, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any range between the two mentioned above.

[0116] Specifically, the mass percentage of PEG600 includes, but is not limited to: 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, or any range between the two for the foregoing.

[0117] Other examples of this application provide the application of the water-washable flux compositions described above in the surface mount assembly of electronic circuits. It is understood that this is specifically applied to the soldering process in the surface mount assembly of electronic circuits. Further, the soldering process is soldering.

[0118] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0119] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0120] Examples 1-7 and Comparative Examples 1-5 respectively provide water-washable flux compositions, and their formulations by mass percentage are shown in Tables 1 and 2 below:

[0121] Table 1

[0122]

[0123] Table 2

[0124]

[0125] The preparation methods of the water-washed flux compositions of Examples 1-7 and Comparative Examples 1-5 are as follows:

[0126] (1) Mix the components in the formula in a stainless steel metal container according to the corresponding mass percentage, heat to 60℃~70℃, and stir continuously for 30min;

[0127] (2) Continue heating to 90°C, and stir while maintaining the temperature until all components are fully dissolved;

[0128] (3) After the system is fully dissolved, cool it down to 50±5℃ and discharge it. Store it in an environment of 0℃~10℃. When using it, it can be warmed up at room temperature.

[0129] Test example:

[0130] (1) Water washing performance: The prepared water-washable flux composition was warmed at room temperature (23°C) for two hours. The flux was applied to the metal sites on the substrate. The ball fell on the metal site coated with flux. The flux could stick the ball. Then, it was soldered through a reflow oven. After the ball was reflowed, the substrate surface was rinsed with 50°C hot water at a flow rate of 1L / min for 5 minutes. After rinsing, it was dried with nitrogen. The amount of impurities remaining on the substrate surface was observed under a microscope. Since the substrate area and the number of balls were fixed for each test, the residual flux ratio on the substrate could be calculated by counting the number of residual solder balls around it. The water washing performance test results of the water-washable flux composition in Example 2 are as follows: Figure 1 As shown, the post-weld cleaning effect is good, with no residue. The welding effect between the ball and the substrate is good, with no ball falling off. The ball has no voids after welding, has a good forming effect, and has high reliability.

[0131] (2) Corrosivity: After the flux is applied to the copper solder joints on the substrate, the morphological changes of the substrate or solder ball surface are observed under a microscope. By comparing the differences before and after the use of flux, "significant corrosion" means that the morphology changes significantly before and after use, "slight corrosion" means that the morphology changes slightly before and after use, and "no" corrosion means that the morphology remains basically unchanged and there is no visible corrosion.

[0132] (3) Uniformity: The uniformity of flux coating on the substrate. The flux is applied to the substrate surface and left to stand for 30 minutes. The diameter of the circular size of the flux naturally spreading on the copper pads of the substrate is measured under a microscope. The average, maximum and minimum values ​​of the flux on 10 pads are statistically analyzed. The uniformity data is obtained by calculating Y = (maximum value - minimum value) / (2 * average value) * 100%. Y < 5% indicates "good" uniformity, 5% < Y < 10% indicates "average" uniformity, and > 10% indicates "poor" uniformity.

[0133] (4) Solder ball stability - whether shear force is PASS: This is tested using a push-pull force meter. The push-pull force meter applies a fixed force to the cutting head to push the solder ball on the pad. The computer collects the force required to push the solder ball to determine whether it meets the requirements for solder ball stability. Since different sizes of solder balls correspond to different soldering strengths, generally speaking, the larger the ball diameter, the larger the soldering surface area, and the greater the required push-pull force. Since flux is generally used for the ball placement process of 150um diameter solder balls, this value is used as the laboratory evaluation requirement. The push-pull force value is >3mg / μm. 2 If the push or pull force is insufficient, it indicates a pass; if insufficient force is applied, it indicates a fail.

[0134] (5) Solder ball stability - void rate: X-ray is used to irradiate a fixed area of ​​the solder ball and the void situation is statistically analyzed.

[0135] (6) Solder ball stability - ball drop: Observe under a microscope whether any balls have fallen off.

[0136] The test results are shown in Table 3 below:

[0137] Table 3

[0138]

[0139] A comparison between the examples and comparative examples shows that the present application, by using organic acids, amine corrosion inhibitors supplemented with alcohol ether compounds, surfactants and solvents, and reasonably controlling the mass percentage of each component, can effectively improve the corrosivity of the formulation. At the same time, it can enhance the wetting ability, easy cleaning performance and uniformity of the formulation, and ensure the adhesion of flux to the substrate and the adsorption of solder balls to the substrate, thus maintaining the stability of the flux morphology on the substrate.

[0140] 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.

[0141] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. 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 scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A water-washable flux composition, characterized in that, By weight percentage, it includes the following components: Organic acids 2%~10%, Amine corrosion inhibitors 5%~30%, At least one of alcohol ethers, phenyl crown ethers, and 18-crown-6-ethers, comprising 30% to 50% Surfactants 1%~15%, and Solvent 30%~50%; The organic acids include one or more of the following: citric acid, malic acid, glutaric acid, diethylene glycol, thionyl diacetic acid, tartaric acid, trimeric acid, itaconic acid, azelaic acid, glycolic acid, phenylsuccinic acid, malonic acid, succinic acid, adipic acid, mercaptoacetic acid, and salicylic acid. The amine corrosion inhibitors include one or more of the following: glutamine, monoethanolamine, diethanolamine, triethanolamine, dibutylamine, o-methoxyaniline, tetrahydroxypropylethylenediamine, triisopropanolamine, ethylenediamine, polyoxyalkylene alkylamine, isopropylamine, and butylamine; The alcohol ether compounds include one or more of dipropylene glycol butyl ether, diethylene glycol butyl ether, tripropylene glycol butyl ether, ethylene glycol butyl ether, triethylene glycol propyl ether, propylene glycol butyl ether, and diethylene glycol propyl ether; The surfactant includes one or more of alkyl glycosides, methyl glucosides, n-octyl glucosides, decyl glucosides, lauryl glucosides, alkylphenol polyoxyethylene ethers, C12~C18 fatty alcohol polyoxyethylene ethers, bisphenol A polyoxyethylene ethers, and EO / PO block polyethers. The solvent includes one or more polymerizable alcohol compounds and nonpolymerizable alcohol compounds with a molecular weight of less than or equal to 1000.

2. The water-washable flux composition according to claim 1, characterized in that: The water-washable flux composition has at least one of the following characteristics: (1) The organic acid is selected from the group consisting of citric acid, malic acid and trimeric acid, malic acid and tartaric acid, glycolic acid, thionyl diacetic acid, malic acid, malonic acid and adipic acid. (2) The amine corrosion inhibitor is selected from one or more of triethanolamine, ethylenediamine, tetrahydroxypropylethylenediamine, triisopropanolamine, dibutylamine, and diethanolamine; (3) The alcohol ether compound is selected from the group consisting of dipropylene glycol butyl ether, or ethylene glycol butyl ether and propylene glycol butyl ether, or phenyl crown ether, or diethylene glycol propyl ether, or diethylene glycol butyl ether; (4) The surfactant is selected from one or more of isooctylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, alkyl glycoside, octylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether AEO-3; (5) The solvent is selected from polyethylene glycol 800, or propylene glycol, or glycerol, or ethylene glycol, or glycerin, or the group consisting of polyethylene glycol 600 and ethylene glycol, or polyethylene glycol 600.

3. The water-washable flux composition according to claim 2, characterized in that: The water-washable flux composition has at least one of the following characteristics: (1) The organic acid is selected from the group consisting of malic acid, glycolic acid, thionyl diacetic acid, malonic acid and adipic acid; (2) The amine corrosion inhibitor is selected from one or more of ethylenediamine, triisopropanolamine, dibutylamine, and diethanolamine; (3) The alcohol ether compound is selected from the group consisting of ethylene glycol butyl ether and propylene glycol butyl ether, or diethylene glycol propyl ether, or diethylene glycol butyl ether; (4) The surfactant is selected from one or more of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether AEO-3, and alkyl glycoside; (5) The solvent is selected from propylene glycol, or ethylene glycol, or glycerol, or the group consisting of polyethylene glycol 600 and ethylene glycol, or polyethylene glycol 600.

4. The water-washable flux composition according to claim 1, characterized in that, The pH of the water-washable flux composition is 4-7.

5. The water-washable flux composition according to claim 1, characterized in that, The mass ratio of the organic acid to the amine corrosion inhibitor is 1:(0.5-3.5).

6. The water-washable flux composition according to any one of claims 1 to 5, characterized in that, By weight percentage, it includes the following components: Citric acid 2%~5%, triethanolamine 5%~10%, dipropylene glycol butyl ether 40%~50%, isooctylphenol polyoxyethylene ether 1%~5%, and polyethylene glycol 800 40%~50%.

7. The water-washable flux composition according to any one of claims 1 to 5, characterized in that, By weight percentage, it includes the following components: Malic acid and triglycerides 2%~6%, ethylenediamine 5%~15%, ethylene glycol butyl ether and propylene glycol butyl ether 40%~50%, nonylphenol polyoxyethylene ether 5%~15%, and propylene glycol 30%~40%.

8. The water-washable flux composition according to any one of claims 1 to 5, characterized in that, By weight percentage, it includes the following components: Malic acid and tartaric acid 4%~8%, tetrahydroxypropyl ethylenediamine 5%~15%, phenyl crown ether 30%~40%, alkyl glycoside 10%~15%, and glycerol 35%~45%.

9. The water-washable flux composition according to any one of claims 1 to 5, characterized in that, By weight percentage, it includes the following components: Glycolic acid 5%~10%, triisopropanolamine 15%~25%, diethylene glycol propyl ether 30%~40%, octylphenol polyoxyethylene ether 5%~15%, and ethylene glycol 30%~40%.

10. The water-washable flux composition according to any one of claims 1 to 5, characterized in that, By weight percentage, it includes the following components: The ingredients include 2%~8% thionyl diacetic acid, 10%~20% dibutylamine, 35%~45% diethylene glycol butyl ether and propylene glycol butyl ether, 1%~5% fatty alcohol polyoxyethylene ether AEO-3, and 40%~50% glycerol.

11. The water-washable flux composition according to any one of claims 1 to 5, characterized in that, By weight percentage, it includes the following components: Malic acid 2%~8%, triisopropanolamine 10%~20%, diethylene glycol butyl ether 30%~50%, nonylphenol polyoxyethylene ether 1%~10%, and polyethylene glycol 600 and ethylene glycol 40%~50%.

12. The water-washable flux composition according to any one of claims 1 to 5, characterized in that, By weight percentage, it includes the following components: Malonic acid and adipic acid 3%~7%, diethanolamine 5%~10%, diethylene glycol propyl ether 35%~45%, alkyl glycosides 2%~10%, and polyethylene glycol 600 35%~45%.

13. The use of the water-washable flux composition according to any one of claims 1 to 12 in surface mount assembly of electronic circuits.

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