Flux cleaning composition

Abstract

To provide a flux cleaning composition.SOLUTION: A flux cleaning composition according to the present invention comprises, based on the total weight of the flux cleaning composition being 100%, includes: 2% to 20% of an amphoteric surfactant; 0.1% to 2% of a reducing agent; 5% to 10% of a chelating agent; 70% to 90% of an organic solvent; and 2.5% to 20% of water.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a cleaning composition, and particularly to a flux cleaning composition.

Background Art

[0002] In the assembly of electronic components, soldering is usually required. Since an oxide film is likely to be formed on the metal surface of the solder joint at high temperatures, it becomes difficult for the solder material (such as tin) to adhere to the metal surface. Therefore, in the soldering process, flux is used to chemically remove the oxide layer on the surface of the soldered metal, prevent re-oxidation of the surface during soldering, and facilitate the progress of soldering with tin. However, solder and flux residues remain in the gaps of the printed circuit board, making cleaning difficult.

[0003] Normally, since flux contains rosin as a main component, halogenated hydrocarbons such as fluorocarbons have been used in the prior art to clean rosin-based flux. However, halogenated hydrocarbons are highly toxic and carcinogenic to the human body. Furthermore, volatile halogenated hydrocarbons not only destroy the ozone layer but also may be distributed and circulated in the atmosphere, water, and soil by precipitation, surface runoff, etc., having a great adverse impact on the environment.

[0004] Therefore, it is an important issue for this industry to overcome the above-mentioned drawbacks by developing a flux cleaning composition that can be effectively cleaned and is environmentally friendly through component improvement.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technical problem to be solved by the present invention is to provide a flux cleaning composition in view of the deficiencies of the prior art.

Means for Solving the Problems

[0006] The flux cleaning composition contains, based on 100% of the total weight of the flux cleaning composition, 2% to 20% of an amphoteric surfactant, 0.1% to 2% of a reducing agent, 5% to 10% of a chelating agent, 70% to 90% of an organic solvent, and 2.5% to 20% of water.

[0007] In certain embodiments of the present invention, the amphoteric surfactant is an alcohol amine.

[0008] In certain embodiments of the present invention, the amphoteric surfactant is polyoxypropylene propyl ether, lauryl betaine, cocamidopropyl betaine, 3,7,11-trimethyldodecan-3-ol, neopentyl glycol dinonanoate, ethambutol, N,N’-bis(3-aminopropyl)-1,3-propanediamine, di(3-aminopropoxy)ethane, or a combination thereof.

[0009] In certain embodiments of the present invention, the reducing agent is stannous chloride, ferrous sulfate, titanium trichloride, reduced iron powder, oxalic acid, sodium thiosulfate, sodium sulfite, hypophosphorous acid, dithiothreitol, or a combination thereof.

[0010] In certain embodiments of the present invention, the chelating agent is ethylenediamine, 2,2’-bipyridine, 1,10-phenanthroline, oxalate, ethylenediaminetetraacetic acid, 1,2-bis(dimethylarsino)benzene, citric acid, malic acid, or a combination thereof.

[0011] In certain embodiments of the present invention, the organic solvent is ethylene glycol monoalkyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, diethylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, diethylene glycol dialkyl ether, or a combination thereof.

[0012] In certain embodiments of the present invention, the content of the amphoteric surfactant is 5% - 10%.

[0013] In certain embodiments of the present invention, the content of the reducing agent is 0.5% - 1%.

[0014] In certain embodiments of the present invention, the content of the chelating agent is 6% - 8%.

[0015] In certain embodiments of the present invention, the content of the organic solvent is 80% - 85%.

[0016] In certain embodiments of the present invention, the content of the water is 8% - 13%.

[0017] In certain embodiments of the present invention, the flash point of the organic solvent is 100°C - 110°C.

[0018] In certain embodiments of the present invention, the pH of the organic solvent is 8 - 9.

[0019] In certain embodiments of the present invention, the weight ratio of the amphoteric surfactant to the reducing agent (amphoteric surfactant: reducing agent) is 15:1 - 20:1.

[0020] In certain embodiments of the present invention, the chroma of the flux cleaning composition after being heated at 95°C for 168 hours is less than 15G.

Advantages of the Invention

[0021] As one of the advantageous effects of the present invention, the flux cleaning composition according to the present invention provides a formulation that effectively cleans flux without containing halogenated hydrocarbons, replacing existing halogenated hydrocarbon-based cleaning agents, due to the technical feature that "taking the total weight of the flux cleaning composition as 100%, it contains 2% - 20% of an amphoteric surfactant, 0.1% - 2% of a reducing agent, 5% - 10% of a chelating agent, 70% - 90% of an organic solvent, and 2.5% - 20% of water".

Embodiments for Carrying out the Invention

[0022] For a better understanding of the features and technical content of the present invention, please refer to the following detailed description of the present invention. However, the provided detailed description is only for reference and explanation, and is not for limiting the scope of the claims of the present invention.

[0023] Hereinafter, the implementation mode of the "flux cleaning composition" according to the present invention will be described according to a predetermined specific embodiment, and those skilled in the art can understand the advantages and effects of the present invention based on the content disclosed in this specification. The present invention can be implemented or applied by other different specific embodiments, and for each detail in this specification, various modifications and changes can be made based on different viewpoints and uses without departing from the concept of the present invention. The technical content of the present invention will be further described in detail based on the following embodiments, but the scope of protection of the present invention will not be limited by the disclosed content.

[0024] The present invention provides a flux cleaning composition. Specifically, the present invention provides a flux cleaning composition that does not contain halogenated hydrocarbons. Even without containing halogenated hydrocarbons, in order to maintain good cleaning ability for rosin-based fluxes, in the present invention, an amphoteric surfactant is used instead of halogenated hydrocarbons to provide a cleaning effect. Specifically, the amphoteric surfactant may be alcohol amines.

[0025] For example, the amphoteric surfactant may be polyoxypropylene propyl ether, lauryl betaine, cocamidopropyl betaine, 3,7,11-trimethyldodecan-3-ol, neopentyl glycol dinonanoate, ethanebutol, N,N'-bis(3-aminopropyl)-1,3-propanediamine, bis(3-aminopropoxy)ethane, or a combination thereof. However, the above examples are merely one feasible embodiment and the present invention is not limited thereto. In a preferred embodiment of the present invention, the amphoteric surfactant may be polyoxypropylene propyl ether, ethanebutol, N,N'-bis(3-aminopropyl)-1,3-propanediamine, or bis(3-aminopropoxy)ethane. In a more preferred embodiment of the present invention, the amphoteric surfactant may be polyoxypropylene propyl ether or ethanebutol.

[0026] In one embodiment, the content of the amphoteric surfactant is 2% to 20% of the total weight of the flux cleaning composition, that is, 2% to 20% and any positive number therebetween, for example, 2%, 2.5%, 3%, 4%, 5%, 5.5%, 6%, 7%, 8%, 9%, 10%, 10.5%, 11%, 12%, 13%, 14%, 15%, 15.5%, 16%, 17%, 18%, 19%, or 20%. If the content of the amphoteric surfactant is less than 2%, the cleaning effect of the flux cleaning composition on rosin-based flux is poor. If the content of the amphoteric surfactant exceeds 20%, excessive foam will be generated when using the flux cleaning composition. In a preferred embodiment, the content of the amphoteric surfactant may be 5% to 10%.

[0027] However, after the amphoteric surfactant is heated, its color may become darker. In order to avoid the influence on the use of the flux cleaning composition due to the darker color of the amphoteric surfactant, the flux cleaning composition of the present invention may further contain a reducing agent so as to avoid the oxidation of the surfactant and stabilize the components of the flux cleaning composition. In other words, the reducing agent of the present invention is an antioxidant for the amphoteric surfactant.

[0028] For example, the reducing agent may be stannous chloride, ferrous sulfate, titanium trichloride, reduced iron powder, oxalic acid, sodium thiosulfate, sodium sulfite, hypophosphorous acid, dithiothreitol, or a combination thereof. However, the above examples are merely one feasible embodiment and the present invention is not limited thereto. In a preferred embodiment of the present invention, the reducing agent may be stannous chloride or sodium sulfite.

[0029] In one embodiment, the content of the reducing agent is 0.1% - 2% of the total weight of the flux cleaning composition, that is, 0.1% - 2% and any positive number therebetween, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%. If the content of the reducing agent is less than 2%, the maximum antioxidant effect of the amphoteric surfactant will be poor. If the content of the reducing agent exceeds 2%, it will result in an unnecessary increase in the process cost for the flux cleaning composition of the present invention. In a preferred example, the content of the amphoteric surfactant may be 0.5% - 1%. It should be noted that in order to effectively utilize the reducing agent to achieve the best antioxidant effect of the amphoteric surfactant, the weight ratio of the amphoteric surfactant to the reducing agent is 15:1 - 20:1. For example, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1.

[0030] In addition, when cleaning a printed circuit board, metal ions are likely to dissolve, which affects the performance of the flux cleaning agent composition. Therefore, the present invention may include a chelating agent capable of forming a coordination or chelate with a metal or metal oxide so as to maintain the cleaning ability of the composition for flux cleaning. In certain embodiments, the content of the chelating agent is 5% to 10% of the total weight of the composition for flux cleaning, that is, 5% to 10% and any positive number therebetween, for example, it may be 5%, 6%, 7%, 8%, 9%, or 10%. If the content of the chelating agent is less than 5%, the resulting cleaning composition cannot overcome the problem of being affected by metal ions, and if the content of the chelating agent exceeds 10%, it is not economical. In a preferred embodiment, the content of the chelating agent is 6% to 8%.

[0031] For example, the chelating agent may be ethylenediamine, 2,2'-bipyridine, 1,10-phenanthroline, oxalate, ethylenediaminetetraacetic acid (EDTA), 1,2-bis(dimethylarsino)benzene, citric acid, malic acid, or a combination thereof. However, the above examples are only one feasible embodiment and the present invention is not limited thereto. In a preferred embodiment of the present invention, the chelating agent may be citric acid or malic acid, and they have good stability in the composition for flux cleaning of the present invention.

[0032] In the composition for flux cleaning of the present invention, an amphoteric surfactant, a reducing agent, and a chelating agent may be uniformly mixed using an organic solvent. For example, the organic solvent may be ethylene glycol monoalkyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, diethylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, diethylene glycol dialkyl ether, or a combination thereof. However, the above examples are merely one feasible embodiment, and the present invention is not limited thereto. In order to maintain the stability of the composition for flux cleaning and avoid crystal precipitation, in a preferred embodiment of the present invention, the organic solvent may be ethylene glycol monoalkyl ether.

[0033] In one embodiment, the content of the organic solvent may be 70% - 90% of the total weight of the composition for flux cleaning, that is, 70% - 90% and any positive number therebetween. For example, it may be 70%, 75%, 80%, 85%, or 90%. If the content of the organic solvent is less than 70%, the amphoteric surfactant, the reducing agent, and the chelating agent cannot be uniformly mixed, which affects the stability of the formulation of the composition for flux cleaning. If the content of the organic solvent exceeds 90%, the concentration of the effective cleaning components in the composition for flux cleaning is too low, which affects the cleaning effect of the composition for flux cleaning. In a preferred embodiment, the content of the amphoteric surfactant may be 80% - 85%.

[0034] Moreover, in order for the composition for flux cleaning of the present invention to adapt to the use environment at an operating temperature of about 75°C, it is preferable to select a flash point of 100°C - 110°C in the present invention, and it is more preferable to select an organic solvent with a flash point of 105°C. At the same time, in order to avoid the composition for flux cleaning causing corrosion to the circuit board at the operating temperature, the pH of the organic solvent may be 8 - 9 and any positive number therebetween.

[0035] Taking the total weight of the flux cleaning composition as 100%, in the flux cleaning composition of the present invention, in addition to the amphoteric surfactant, reducing agent, chelating agent, and organic solvent, the remainder may contain water. In other words, the water content may be 2.5% to 20% of the total weight of the flux cleaning composition, that is, 2.5% to 20% and any positive number therebetween, for example, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 10%, 15%, or 20%. Preferably, the water content is 8% to 13% of the total weight of the flux cleaning composition. It should be noted that in order to achieve the effect of uniformly mixing the amphoteric surfactant, reducing agent, and chelating agent and obtain a stable flux cleaning composition, the value of the ratio of the organic solvent to water is 10 to 35 and any positive number therebetween, for example, 10, 12, 14, 17.8, 22.9, 25, 28, or 32, and preferably 15 to 32.

Examples

[0036] Hereinafter, the present invention will be further described by examples so that those skilled in the art can more easily understand the advantages of the flux cleaning composition of the present invention, but the present invention is not limited to the scope of these examples. In the examples described below, the components were mixed simultaneously or based on any order. Unless otherwise specified, “% (percentage of concentration)” in this specification is all expressed as “wt% (percentage by weight)”.

[0037] [Example 1] 8% polyoxypropylene propyl ether, 0.5% stannous chloride, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 4.5% water were uniformly mixed and stirred, and then filtered to obtain the flux cleaning composition E1 which is Example 1 of the present application.

[0038] [Example 2] 8% polyoxypropylene propyl ether, 0.5% sodium sulfite, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 4.5% water were uniformly mixed and stirred, and then filtered to obtain the flux cleaning composition E2 of Example 2 of the present application.

[0039] [Example 3] 9% polyoxypropylene propyl ether, 0.5% hypophosphorous acid, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 3.5% water were uniformly mixed and stirred, and then filtered to obtain the flux cleaning composition E3 of Example 3 of the present application.

[0040] [Example 4] 10% polyoxypropylene propyl ether, 0.5% dithiothreitol, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 2.5% water were uniformly mixed and stirred, and then filtered to obtain the flux cleaning composition E4 of Example 4 of the present application.

[0041] [Example 5] 8% ethanediol butyl ether, 0.5% stannous chloride, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 4.5% water were uniformly mixed and stirred, and then filtered to obtain the flux cleaning composition E5 of Example 5 of the present application.

[0042] [Example 6] 8% ethanediol butyl ether, 0.5% sodium sulfite, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 4.5% water were uniformly mixed and stirred, and then filtered to obtain the flux cleaning composition E6 of Example 6 of the present application.

[0043] [Example 7] 9% ethanediol butyl ether, 0.5% hypophosphorous acid, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 3.5% water were uniformly mixed and stirred, and then filtered to obtain the flux cleaning composition E7 of Example 7 of the present application.

[0044] [Example 8] 10% ethanol, 0.5% dithiothreitol, 7% citric acid, 80% ethylene glycol monoalkyl ether, and 2.5% water were uniformly mixed and stirred, and then filtered to obtain the flux washing composition E8 of Example 8 of the present application.

[0045] [Example 9] 15% polyoxypropylene propyl ether, 1% stannous chloride, 7% malic acid, 70% ethylene glycol monoalkyl ether, and 7% water were uniformly mixed and stirred, and then filtered to obtain the flux washing composition E9 of Example 9 of the present application.

[0046] [Example 10] 15% ethanol, 1% sodium sulfite, 7% malic acid, 70% ethylene glycol monoalkyl ether, and 7% water were uniformly mixed and stirred, and then filtered to obtain the flux washing composition E10 of Example 10 of the present application.

[0047] [Comparative Example] 15% polyoxypropylene propyl ether, 7% citric acid, 70% ethylene glycol monoalkyl ether, and 8% water were uniformly mixed and stirred, and after filtration, it was used as Comparative Example C.

[0048] To measure and evaluate the detergency, a circuit board for measurement of the residue of rosin-based flux was immersed in the flux washing composition at 75°C, and then washed and dried with nitrogen. After the washing step, the circuit board for measurement was observed with a microscope and visually inspected. When there was no residue of flux, it was described as "O", and when there was a residue of flux, it was described as "X".

[0049] [Measurement of Color Depth] The flux washing composition was heated at 95°C for 168 hours, and the chroma was measured with a colorimeter. The lower the value of the color depth, the lighter the color. The formulations and test results of the components of each example were recorded in Table 1 below.

[0050]

Table 1

[0051] As shown in Table 1, the flux cleaning composition of the present invention does not contain halogenated hydrocarbons, and by using an amphoteric surfactant as the main cleaning component, it surely has a cleaning power against rosin-based fluxes. Therefore, in the present invention, by a specific formulation of the composition, by using only an amphoteric surfactant, a reducing agent, a chelating agent, an organic solvent and water, the effect of providing a flux cleaning composition with strong cleaning power, safety and environmental friendliness is achieved, and there is an economic effect in the actual application of cleaning rosin-based fluxes.

[0052] It should be noted that, as shown in Comparative Example C, the amphoteric surfactant contained in the flux cleaning composition may become darker in color after being heated. In Examples E1 to E10 of the present invention, a reducing agent with a specific content is added with respect to the content of the amphoteric surfactant, and the problem that the flux cleaning composition becomes darker in color after being heated can be improved compared with Comparative Example C. Here, in Example 5, ethanol and stannous chloride are used in combination, and the effect of improving the problem that the flux cleaning composition becomes darker in color after being heated is the most excellent.

[0053] [Advantageous Effects According to Embodiments] As one of the advantageous effects of the present invention, the flux cleaning composition according to the present invention, with the technical feature of "including 2% - 20% of an amphoteric surfactant, 0.1% - 2% of a reducing agent, 5% - 10% of a chelating agent, 70% - 90% of an organic solvent, and 2.5% - 20% of water, with the total weight of the flux cleaning composition being 100%", provides a formulation that can effectively clean fluxes without containing halogenated hydrocarbons, replacing the existing halogenated hydrocarbon-based cleaning agents.

[0054] Furthermore, the addition of a reducing agent is for avoiding discoloration caused by oxidation when the amphoteric surfactant is heated. Therefore, in order to use the reducing agent to have an economic effect, in the flux cleaning composition of the present invention, the weight ratio of the amphoteric surfactant to the reducing agent is 15:1 to 20:1.

[0055] Also, since the flux cleaning composition of the present invention simultaneously contains an amphoteric surfactant, a reducing agent, and a chelating agent, in order to uniformly mix the amphoteric surfactant, the reducing agent, and the chelating agent to achieve an optimal use effect, the value of the ratio of the organic solvent to water is controlled to be 10 to 35. Preferably, the value of the ratio of the organic solvent to water is 15 to 32.

[0056] The content disclosed above is only a preferred feasible embodiment of the present invention, and the scope of the claims of the present invention is not limited thereto. Therefore, all equivalent technical changes made using the content of the specification and drawings of the present invention are included in the scope of the claims of the present invention.

Claims

1. Taking the total weight of the flux cleaning composition as 100%, 2% - 20% of an amphoteric surfactant, 0.1% - 2% of a reducing agent, 5% - 10% of a chelating agent, 70% - 90% of an organic solvent, 2.5% - 20% of water, and characterized by comprising a flux cleaning composition.

2. The flux cleaning composition according to claim 1, wherein the amphoteric surfactant is an alcohol amine.

3. The flux cleaning composition according to claim 1, wherein the amphoteric surfactant is polyoxypropylene propyl ether, lauryl betaine, cocamidopropyl betaine, 3,7,11 - trimethyldodecan - 3 - ol, neopentyl glycol dinonanoate, ethanebutanol, N,N’ - bis(3 - aminopropyl) - 1,3 - propanediamine, bis(3 - aminopropoxy)ethane, or a combination thereof.

4. The flux cleaning composition according to claim 1, wherein the reducing agent is stannous chloride, ferrous sulfate, titanium trichloride, reduced iron powder, oxalic acid, sodium thiosulfate, sodium sulfite, hypophosphorous acid, dithiothreitol, or a combination thereof.

5. The flux cleaning composition according to claim 1, wherein the chelating agent is ethylenediamine, 2,2’ - bipyridine, 1,10 - phenanthroline, oxalate, ethylenediaminetetraacetic acid, 1,2 - bis(dimethylarsino)benzene, citric acid, malic acid, or a combination thereof.

6. The flux cleaning composition according to claim 1, wherein the organic solvent is ethylene glycol monoalkyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, diethylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, diethylene glycol dialkyl ether, or a combination thereof.

7. The flux cleaning composition according to claim 1, wherein the content of the amphoteric surfactant is 5% - 10%.

8. The flux cleaning composition according to claim 1, wherein the content of the reducing agent is 0.5% - 1%.

9. The flux cleaning composition according to claim 1, wherein the content of the chelating agent is 6% - 8%.

10. The flux cleaning composition according to claim 1, wherein the content of the organic solvent is 80% - 85%.

11. The flux cleaning composition according to claim 1, wherein the water content is 8% to 13%.

12. The flux cleaning composition according to claim 1, wherein the flash point of the organic solvent is 100°C to 110°C.

13. The flux cleaning composition according to claim 1, wherein the pH of the organic solvent is 8 to 9.

14. The flux cleaning composition according to claim 1, wherein the weight ratio of the amphoteric surfactant to the reducing agent (amphoteric surfactant: reducing agent) is 15:1 to 20:

1.

15. The flux cleaning composition according to claim 1, wherein the chroma after the flux cleaning composition is heated at 95°C for 168 hours is less than 15 G.

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