Flux cleaning composition

Abstract

The invention discloses a flux cleaning composition. The total weight of the flux cleaning composition is 100%, and the flux cleaning composition comprises 2%-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 5% to 20% of water. The flux cleaning composition disclosed by the invention can provide a formula which does not contain halogenated hydrocarbon and can still effectively clean the flux.

Description

Technical Field

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

[0002] During electronic assembly, soldering is usually required. Since the metal surface of the solder joint is prone to form an oxide layer at high temperatures, it is difficult for soldering materials (such as tin) to adhere to the metal surface. Therefore, fluxes are used during the soldering process to chemically remove the oxide layer on the surface of the metal to be soldered and prevent re-oxidation of the surface during soldering, facilitating the progress of tin soldering. However, the residues of the solder and the flux remain in the gaps of the printed circuit board, making cleaning difficult.

[0003] Since fluxes usually have rosin as the main component, halogenated hydrocarbons such as chlorofluorocarbons are used in the prior art to clean rosin-based fluxes. However, halogenated hydrocarbons are highly toxic and carcinogenic to humans. In addition, volatile halogenated hydrocarbons can damage the ozone layer and can also be distributed and circulated in the atmosphere, water, and soil through precipitation, surface runoff, etc., having a great negative impact on the environment.

[0004] Therefore, how to develop an effective and environmentally friendly flux cleaning composition through the improvement of the ingredient formulation to overcome the above defects has become one of the important issues to be solved in this field. Summary of 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. Taking the total weight of the flux cleaning composition as 100%, it 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 5% to 20% of water.

[0006] Furthermore, the amphoteric surfactant is an alcohol amine.

[0007] Furthermore, the amphoteric surfactant is propanol polyoxypropylene ether, lauryl betaine, coconut amide propyl betaine, 3,7,11-trimethyldodecan-3-ol, neopentyl glycol dinonanoate, ethambutol, N,N'-bis(3-aminopropyl)-1,3-propanediamine, bis(3-aminopropoxy)ethane, and mixtures thereof.

[0008] Furthermore, the reducing agent is stannous chloride, ferrous sulfate, titanium trichloride, reduced iron powder, oxalic acid, sodium thiosulfate, sodium sulfite, hypophosphorous acid, dithiothreitol, and mixtures thereof.

[0009] Further, the chelating agent is ethylenediamine, 2,2'-bipyridine, 1,10-phenanthroline, oxalate, ethylenediaminetetraacetic acid, 1,2-bis(dimethylarsino)benzene, citric acid, malic acid, and mixtures thereof.

[0010] Further, 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, and mixtures thereof.

[0011] Further, the content of the amphoteric surfactant is 5% to 10%.

[0012] Further, the content of the reducing agent is 0.5% to 1%.

[0013] Further, the content of the chelating agent is 6% to 8%.

[0014] Further, the content of the organic solvent is 80% to 85%.

[0015] Further, the content of the water is 8% to 13%.

[0016] Further, the flash point of the organic solvent is 100 to 110 °C.

[0017] Further, the pH of the organic solvent is 8 to 9.

[0018] Further, the weight ratio of the amphoteric surfactant to the reducing agent is 15:1 to 20:1.

[0019] Further, the colority of the flux cleaning composition after heating at 95 °C for 168 hours is less than 15 G.

[0020] One beneficial effect of the present invention is that the flux cleaning composition provided by the present invention can provide a formula that does not contain halogenated hydrocarbons and can still effectively clean the flux through the technical solution of "taking the total weight of the flux cleaning composition as 100%, which includes: 2% to 20% of amphoteric surfactant; 0.1% to 2% of reducing agent; 5% to 10% of chelating agent; 70% to 90% of organic solvent; and 5% to 20% of water", so as to replace the existing halogenated hydrocarbon cleaning agent.

[0021] To further understand the features and technical content of the present invention, please refer to the following detailed description of the present invention. However, the detailed description provided is only for reference and illustration, and is not used to limit the present invention. Detailed Description of the Invention

[0022] The following is a description of the embodiments of the "flux cleaning composition" disclosed in the present invention through specific specific examples. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. The following embodiments will further detail the related technical content of the present invention, but the disclosed content is not intended to limit the protection scope of the present invention.

[0023] The present invention provides a flux cleaning composition. Specifically, the present invention provides a flux cleaning composition without halogenated hydrocarbons. In order to enable the flux cleaning composition to still have good cleaning ability for rosin-based fluxes without halogenated hydrocarbons, the present invention can use amphoteric surfactants to replace halogenated hydrocarbons to provide a cleaning effect. Specifically, the amphoteric surfactant can be an alcohol amine.

[0024] For example, the amphoteric surfactant can be propanol polyoxypropylene ether, lauryl betaine, coconut amide propyl betaine, 3,7,11-trimethyldodecan-3-ol, neopentyl glycol dinonanoate, ethambutol, N,N'-bis(3-aminopropyl)-1,3-propanediamine, bis(3-aminopropoxy)ethane, and mixtures thereof. However, the above examples are only one possible embodiment and are not intended to limit the present invention. In a preferred embodiment of the present invention, the amphoteric surfactant can be propanol polyoxypropylene ether, ethambutol, 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 can be propanol polyoxypropylene ether or ethambutol.

[0025] In one embodiment, the content of the amphoteric surfactant can be 2% to 20% of the total weight of the flux cleaning composition, that is, any positive number between 2% and 20%, such as 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 the rosin-based flux will be poor. If the content of the amphoteric surfactant is greater than 20%, excessive foaming will occur during the use of the flux cleaning composition. In a preferred embodiment, the content of the amphoteric surfactant can be 5% to 10%.

[0026] However, the above amphoteric surfactant will darken in color after heating. In order to avoid the darkening of the amphoteric surfactant from affecting the use of the flux cleaning composition, the flux cleaning composition of the present invention may further include a reducing agent to prevent the oxidation of the surfactant and maintain the stability of the components of the flux cleaning composition. In other words, the reducing agent of the present invention is an antioxidant for the above amphoteric surfactant.

[0027] 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, and mixtures thereof. However, the examples given above are only one possible embodiment and are not intended to limit the present invention. In a preferred embodiment of the present invention, the reducing agent may be stannous chloride or sodium sulfite.

[0028] In one embodiment, the content of the reducing agent may be 0.1% to 2% of the total weight of the flux cleaning composition, that is, any positive number between 0.1% and 2%, such as 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 best antioxidant effect of the amphoteric surfactant will not be achieved. If the content of the reducing agent is greater than 2%, it will unnecessarily increase the process cost for the flux cleaning composition of the present invention. In a preferred embodiment, the content of the amphoteric surfactant may be 0.5% to 1%. It is worth mentioning that, in order to effectively utilize the reducing agent and achieve the best antioxidant effect of the amphoteric surfactant, the weight ratio of the amphoteric surfactant to the reducing agent is 15:1 to 20:1. For example, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1.

[0029] In addition, when cleaning a printed circuit board, metal ions are likely to dissolve out and affect the performance of the flux cleaning composition. Therefore, the present invention may further include a chelating agent that can form a coordination element or chelate with a metal or metal oxide to maintain the cleaning ability of the flux cleaning composition. In one embodiment, the content of the chelating agent may be 5% to 10% of the total weight of the flux cleaning composition, that is, any positive number between 5% and 10%, such as 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. If the content of the chelating agent is greater than 10%, it will not be cost-effective. In a preferred embodiment, the content of the chelating agent may be 6% to 8%.

[0030] 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, and mixtures thereof. However, the examples given above are only one possible embodiment and are not intended to limit the present invention. In a preferred embodiment of the present invention, the chelating agent may be citric acid or malic acid, which has good stability in the flux cleaning composition of the present invention.

[0031] The flux cleaning composition of the present invention can use an organic solvent to uniformly mix an amphoteric surfactant, a reducing agent, and a chelating agent. 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, and mixtures thereof. However, the examples given above are only one possible embodiment and are not intended to limit the present invention. To maintain the stability of the flux cleaning composition and avoid crystallization, in a preferred embodiment of the present invention, the organic solvent may be ethylene glycol monoalkyl ether.

[0032] In one embodiment, the content of the organic solvent may be 70% to 90% of the total weight of the flux cleaning composition, that is, any positive number between 70% and 90%, such as 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, thereby affecting the formulation stability of the flux cleaning composition. If the content of the organic solvent is greater than 90%, the effective cleaning concentration in the flux cleaning composition is too low, affecting the cleaning effect of the flux cleaning composition. In a preferred embodiment, the content of the amphoteric surfactant may be 80% to 85%.

[0033] In addition, in order to meet the use scenario where the flux cleaning composition of the present invention is applicable to an operating temperature of about 75°C, the present invention selects an organic solvent with a flash point preferably of 100 to 110°C, more preferably 105°C. At the same time, in order to avoid the flux cleaning composition from being corrosive to the circuit board at the operating temperature, the pH of the organic solvent may be any positive number between 8 and 9.

[0034] Based on the total weight of the flux cleaning composition being 100%, in addition to the zwitterionic surfactant, reducing agent, chelating agent, and organic solvent in the flux cleaning composition of the present invention, the balance may include water. In other words, the water content may be 5% to 20% of the total weight of the flux cleaning composition, that is, any positive number between 5% and 20%, such as 5%, 10%, 15%, or 20%. Preferably, the water content may be 8% to 13% of the total weight of the flux cleaning composition. It is worth mentioning that in order to achieve the effect of uniformly mixing the zwitterionic surfactant, reducing agent, and chelating agent to obtain a stable flux cleaning composition, the ratio of the organic solvent to water may be any positive number between 10 and 35, for example, 10, 12, 14, 17.8, 22.9, 25, 28, or 32, and preferably may be 15 to 32.

[0035] The following will further illustrate the present invention through examples, making it easier for those with ordinary knowledge in the technical field to understand the advantages of the flux cleaning composition of the present invention. However, the present invention is not limited to the scope of the examples. In the following examples, the components will be mixed simultaneously or in any order. Unless otherwise explicitly stated, all percentage concentrations in this case are expressed as weight percentages.

[0036] Example 1

[0037] 8% of propanol polyoxypropylene ether, 0.5% of stannous chloride, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 4.5% of water were mixed, stirred evenly, and filtered to obtain the flux cleaning composition E1 of Example 1 of this case.

[0038] Example 2

[0039] 8% of propanol polyoxypropylene ether, 0.5% of sodium sulfite, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 4.5% of water were mixed, stirred evenly, and filtered to obtain the flux cleaning composition E2 of Example 2 of this case.

[0040] Example 3

[0041] 9% of propanol polyoxypropylene ether, 0.5% of hypophosphorous acid, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 3.5% of water were mixed, stirred evenly, and filtered to obtain the flux cleaning composition E3 of Example 3 of this case.

[0042] Example 4

[0043] 10% of propanol polyoxypropylene ether, 0.5% of dithiothreitol, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 2.5% of water were mixed, stirred evenly, and filtered to obtain the flux cleaning composition E4 of Example 4 of this case.

[0044] Example 5

[0045] Mix 8% of ethambutol, 0.5% of stannous chloride, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 4.5% of water, stir evenly, and filter to obtain the flux cleaning composition E5 of Example 5 of this case.

[0046] Example 6

[0047] Mix 8% of ethambutol, 0.5% of sodium sulfite, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 4.5% of water, stir evenly, and filter to obtain the flux cleaning composition E6 of Example 6 of this case.

[0048] Example 7

[0049] Mix 9% of ethambutol, 0.5% of hypophosphorous acid, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 3.5% of water, stir evenly, and filter to obtain the flux cleaning composition E7 of Example 7 of this case.

[0050] Example 8

[0051] Mix 10% of ethambutol, 0.5% of dithiothreitol, 7% of citric acid, 80% of ethylene glycol monoalkyl ether, and 2.5% of water, stir evenly, and filter to obtain the flux cleaning composition E8 of Example 8 of this case.

[0052] Example 9

[0053] Mix 15% of propanol polyoxypropylene ether, 1% of stannous chloride, 7% of malic acid, 70% of ethylene glycol monoalkyl ether, and 7% of water, stir evenly, and filter to obtain the flux cleaning composition E9 of Example 9 of this case.

[0054] Example 10

[0055] Mix 15% of ethambutol, 1% of sodium sulfite, 7% of malic acid, 70% of ethylene glycol monoalkyl ether, and 7% of water, stir evenly, and filter to obtain the flux cleaning composition E10 of Example 10 of this case.

[0056] Comparative Example

[0057] Mix 15% of propanol polyoxypropylene ether, 7% of citric acid, 70% of ethylene glycol monoalkyl ether, and 8% of water, stir evenly, and filter as Comparative Example C.

[0058] The determination and evaluation of the detergency were carried out by immersing a test circuit board with residual rosin-based flux in the flux cleaning composition at 75°C, and then drying it by purging with nitrogen. After the above cleaning steps, the test circuit board was observed under a microscope for visual confirmation. Those without flux residues were recorded as O, and those with flux residues were recorded as X.

[0059] Color depth test

[0060] The flux cleaning composition was heated at 95°C for 168 hours, and the color depth was measured with a colorimeter. The lower the color depth value, the lighter the color. The component ratios and test results of each example are recorded in Table 1.

[0061] Table 1

[0062]

[0063] As shown in Table 1, the flux cleaning composition of the present invention does not contain halogenated hydrocarbons, and uses an amphoteric surfactant as the main cleaning component, and indeed has detergency for rosin-based fluxes. Therefore, the present invention can achieve the effect of providing a flux cleaning composition with strong detergency, safety, and environmental protection by only using an amphoteric surfactant, a reducing agent, a chelating agent, an organic solvent, and water through specific ratios of the composition, and has economic benefits in the practical application of rosin-based flux cleaning.

[0064] It should be noted that, as shown in Comparative Example C, the color of the flux cleaning composition deepens after heating when it contains an amphoteric surfactant. Examples E1 to E10 of the present invention add a specific content of a reducing agent relative to the content of the amphoteric surfactant, and can improve the problem of color deepening of the flux cleaning composition after heating compared with Comparative Example C. Among them, in Example 5, ethambutol and stannous chloride are used in combination, and the effect of improving the color deepening of the flux cleaning composition after heating is the best.

[0065] Advantages of the examples

[0066] One of the advantages of the present invention is that the flux cleaning composition provided by the present invention can provide a formula that does not contain halogenated hydrocarbons and can still effectively clean fluxes through the technical solution of "taking the total weight of the flux cleaning composition as 100%, which 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 5% to 20% of water", so as to replace the existing halogenated hydrocarbon cleaning agents.

[0067] Furthermore, since the reducing agent is added to prevent the amphoteric surfactant from being oxidized and discolored during heating, in order to use the reducing agent economically, in the flux cleaning composition of the present invention, the weight ratio of the amphoteric surfactant to the reducing agent is from 15:1 to 20:1.

[0068] In addition, since the flux cleaning composition of the present invention includes an amphoteric surfactant, a reducing agent and a chelating agent at the same time, in order to uniformly mix the amphoteric surfactant, the reducing agent and the chelating agent to achieve the best use effect, the ratio of the organic solvent to water is controlled between 10 and 35. Preferably, the ratio of the organic solvent to water is from 15 to 32.

[0069] The above-disclosed content is only the preferred and feasible embodiment of the present invention, and does not limit the protection scope of the claims of the present invention. Therefore, all equivalent technical changes made by using the content of the specification of the present invention are included in the protection scope of the claims of the present invention.

Claims

1. A flux cleaning composition, characterized in that: Taking the total weight of the solder flux cleaning composition as 100%, the solder flux cleaning composition comprises: Amphoteric surfactant 2% to 20%; Reducing agent 0.1% to 2%; Chelating agents 5% to 10%; Organic solvent 70% to 90%; and Water 5% to 20%.

2. The flux cleaning composition according to claim 1, characterized in that The amphoteric surfactant is an alcohol amine.

3. The flux cleaning composition according to claim 1, characterized in that The amphoteric surfactants are propylene glycol polyoxypropylene ether, lauryl betaine, coconut amide propyl betaine, 3,7,11-trimethyldodecane-3-ol, neopentyl glycol dipelargonate, ethambutol, N,N'-bis(3-aminopropyl)-1,3-propylenediamine, bis(3-aminopropoxy)ethane and mixtures thereof.

4. The flux cleaning composition according to claim 1, characterized in that The reducing agent is stannous chloride, ferrous sulfate, titanium trichloride, reduced iron powder, oxalic acid, sodium thiosulfate, sodium sulfite, hypophosphorous acid, dithiothreitol and a mixture thereof.

5. The flux cleaning composition according to claim 1, characterized in that: The chelating agent is ethylenediamine, 2,2'-bipyridine, 1,10-phenanthroline, oxalate, ethylenediaminetetraacetic acid, 1,2-di(dimethylarsine)benzene, citric acid, malic acid and a mixture thereof.

6. The flux cleaning composition according to claim 1, characterized in that: 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 and a mixture thereof.

7. The flux cleaning composition according to claim 1, characterized in that: The content of the amphoteric surfactant is 5% to 10%.

8. The flux cleaning composition according to claim 1, characterized in that: The content of the reducing agent is 0.5% to 1%.

9. The flux cleaning composition according to claim 1, characterized in that: The content of the chelating agent is 6% to 8%.

10. The flux cleaning composition according to claim 1, characterized in that: The content of the organic solvent is 80% to 85%.

11. The flux cleaning composition according to claim 1, characterized in that: The water content is 8% to 13%.

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

13. The flux cleaning composition according to claim 1, characterized in that: The pH of the organic solvent is 8 to 9.

14. The flux cleaning composition according to claim 1, characterized in that: The weight ratio of the amphoteric surfactant to the reducing agent is 15:1 to 20:

1.

15. The flux cleaning composition according to claim 1, characterized in that: The flux removal composition has a chromaticity of less than 15G after heating at 95° C. for 168 hours.

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