A halogen-free organic solderable protective agent and its preparation method

Abstract

This invention discloses a halogen-free organic solderable protective agent and its preparation method, comprising the following components at the following mass concentrations: 2-phenylimidazolium 2.5-5 g / L, 2-benzylbenzimidazole 0.5-1.0 g / L, pyromellitic anhydride 30-60 mg / L, diethylene glycol 1-2 ml / L, ethanol 5-10 ml / L, p-nitrobenzoic acid 10-30 mg / L, and methotrexate 10-30 mg / L; the temperature is 35-45℃; the pH is controlled within the range of 3.8-4.2; and the balance is deionized water. This invention can be widely applied to the surface treatment process of electronic products, achieving a thickness rate of over 0.35 μm in 1 minute. The resulting film is uniform, transparent, and glossy, with strong solderability. It exhibits good resistance to sulfuric acid concentrations below 0.1 mol / L and readily dissociates in 5% hydrochloric acid and 5 ml / L acetone solutions, simplifying rework.

Description

Technical Field

[0001] This invention relates to surface treatment processes, and more particularly to a halogen-free organic solderable protective agent and its preparation method. Background Technology

[0002] Currently used OSP protective agents contain halogens, such as compounds containing chlorine and bromine. While these substances accelerate the deposition rate (up to 0.4-0.5 μm / min), they cause severe migration and corrosion of electronic components under energized conditions, especially in precision circuitry such as packaging substrates and wafers. With increasing circuit density, the probability of migration further increases. Furthermore, environmental issues arise. Developing halogen-free OSP electronic chemicals has become a hot topic. Currently, the domestic market for halogen-free OSP electronic chemicals is largely untapped, while the international market is essentially monopolized by Shikoku. Furthermore, existing halogen-free OSP products on the market have deposition rates in the range of 0.1-0.2 μm / min, fewer than three reflow cycles, and Tg values ​​below 245°C, indicating a need for improvement in performance and production efficiency. Patent CN102523680B provides a prepreg solution and prepreg method for OSP used on printed circuit board surfaces. The prepreg solution for OSP manufacturing on printed circuit board surfaces comprises the following components: benzotriazole 1-30 g / L, N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid 1-10 g / L, alkaline stabilizer 5-30 g / L, pH buffer 1-10 g / L, and organic solvent 200-300 g / L. This OSP solution has poor stability and is prone to ink attack. Furthermore, patent CN107148156A discloses an OSP treatment solution containing a 3,6-dioxa-1,8-octanediaminetetraacetic acid derivative; however, the presence of halogens in this system limits its use in high-end products.

[0003] To address the above issues and achieve self-sufficiency in OSP surface treatment technology for the high-end market, this application provides a halogen-free organic solderable protective agent and its preparation method. Summary of the Invention

[0004] To address the shortcomings of the aforementioned technologies, this invention provides a halogen-free organic solderable protective agent and its preparation method. This invention can be widely applied to surface treatment processes for electronic products, achieving a coating thickness of over 0.35 μm in 1 minute. The resulting film is uniform, transparent, and glossy, exhibiting strong solderability and good resistance to sulfuric acid concentrations below 0.1 mol / L. Furthermore, it readily dissociates in 5% hydrochloric acid and 5 ml / L methanol solutions, simplifying rework.

[0005] To achieve the above objectives, this invention provides a halogen-free organic solderable protective agent and its preparation method, comprising the following components in the indicated mass concentrations: 2-phenylimidazolium 2.5-5 g / L, 2-benzylbenzimidazole 0.5-1.0 g / L, pyromellitic anhydride 30-60 mg / L, diethylene glycol 1-2 ml / L, ethanol 5-10 ml / L, p-nitrobenzoic acid 10-30 mg / L, methotrexate 10-30 mg / L, temperature 35-45℃, pH controlled within the range of 3.8-4.2, and the remainder being deionized water;

[0006] The 2-phenylimidazole, as the main film-forming agent, provides the main components of the film and has greater stability compared with traditional imidazole film-forming agents.

[0007] The 2-benzylbenzimidazole is an auxiliary film-forming agent, which can improve the film layer compositeness and film layer density.

[0008] Methotrexate is a film-forming homogenizer that can make imidazole substances disperse evenly and prevent color difference.

[0009] The feature of this invention is that the pyromellitic anhydride and p-nitrobenzoic acid can improve the film formation rate. Compared with traditional formic acid agents containing only iron salts, the composite accelerator of this application can quickly achieve film formation without precipitation.

[0010] The diethylene glycol and acetic acid provide organic solvents to increase solubility.

[0011] A method for preparing a halogen-free organic solderable protective agent includes the following specific steps:

[0012] A. Dissolve 2-phenylimidazole at a mass concentration of 10 times or more in ethanol at a mass concentration of 10 times the mass concentration of the above solution, and dissolve 2-benzylbenzimidazole at a mass concentration of 10 times or more in diethylene glycol at a mass concentration of 10 times the mass concentration of the above solution to prepare solution 1, wherein the mass ratio of 2-phenylimidazole to 2-benzylbenzimidazole is 5:1.

[0013] B. Add more than 10 times the mass concentration of methotrexate and p-nitrobenzoic acid to solution 1, stir well to obtain solution 2, and obtain concentrated solution 2.

[0014] C. Then, prepare concentrated solution 3 by mixing pyromellitic anhydride 30-60 mg / L at 10 times the above mass concentration.

[0015] D. Take 100 ml of solutions 2 and 3 from each tank, and adjust the pH to 3.8-4.2 with acetic acid or ammonia, and keep the temperature at 38-42℃.

[0016] E. Replenishment method: For every square meter consumed, concentrate 2 and concentrate 3 need to be replenished at a ratio of 1:1, with 5ml of each of the 2 and 3 solutions added.

[0017] The preparation conditions for solutions 2 and 3 are as follows: When dissolving 2-phenylimidazole in ethanol, to prevent ethanol evaporation, add 50 ml / L of deionized water while maintaining the room temperature not exceeding 30°C, and slowly add 2-phenylimidazole while stirring; when dissolving 2-benzylbenzimidazole in diethylene glycol, maintain the temperature not exceeding 35°C, add 50 ml / L of deionized water, and slowly add 2-benzylbenzimidazole while stirring, then mix solutions 2 and 3 evenly and add water to the required level.

[0018] The beneficial effects of this invention are as follows: Compared with the prior art, the halogen-free organic solderable protective agent and its preparation method provided by this invention have the following advantages:

[0019] 1) This invention provides 2-phenylimidazolium as the main film-forming agent to provide the main component of the film, which is more stable than traditional imidazole film-forming agents; 2-benzylbenzimidazole is an auxiliary film-forming agent, which can improve the film layer compositeness and improve the film layer density.

[0020] 2) The methotrexate provided by the present invention is a film-forming homogenizer, which can make imidazole substances uniformly dispersed and less prone to color difference.

[0021] 3) The pyromellitic anhydride and p-nitrobenzoic acid provided by the present invention can improve the film formation rate. Compared with traditional formic acid agents containing only iron salts, the composite accelerator of this application can quickly achieve film formation without precipitation.

[0022] 4) The preparation method of the present invention is simple and soluble, very convenient to use, and the raw materials used are environmentally friendly, with low toxicity and odor, and will not cause harm to workers. Attached Figure Description

[0023] Figure 1 Figures show the results of examples and comparative examples of halogen-free organic solderable protective agents. Detailed Implementation

[0024] To more clearly illustrate the present invention, the invention will be further described below with reference to text and pictures.

[0025] To achieve the above objectives, this invention addresses the shortcomings of the aforementioned technologies by providing a halogen-free organic solderable protective agent and its preparation method, comprising the following components in the indicated mass concentrations: 2-phenylimidazolium 2.5-5 g / L, 2-benzylbenzimidazole 0.5-1.0 g / L, pyromellitic anhydride 30-60 mg / L, diethylene glycol 1-2 ml / L, ethanol 5-10 ml / L, p-nitrobenzoic acid 10-30 mg / L, methotrexate 10-30 mg / L, at a temperature of 35-45℃, with the pH controlled between 3.8 and 4.2, and the remainder being deionized water.

[0026] The 2-phenylimidazole is used as the main film-forming agent.

[0027] In this embodiment, the 2-benzylbenzimidazole is an auxiliary film-forming agent.

[0028] In this embodiment, the characteristic feature is that the methotrexate is a film-forming homogenizer.

[0029] In this embodiment, the pyromellitic anhydride and p-nitrobenzoic acid can improve the film formation rate.

[0030] In this embodiment, the diethylene glycol and acetic acid provide organic solvents to increase solubility.

[0031] A method for preparing a halogen-free organic solderable protective agent includes the following specific steps:

[0032] A. Dissolve 2-phenylimidazole at a mass concentration of 10 times or more in ethanol at a mass concentration of 10 times the mass concentration of the above solution, and dissolve 2-benzylbenzimidazole at a mass concentration of 10 times or more in diethylene glycol at a mass concentration of 10 times the mass concentration of the above solution to prepare solution 1, wherein the mass ratio of 2-phenylimidazole to 2-benzylbenzimidazole is 5:1.

[0033] B. Add more than 10 times the mass concentration of methotrexate and p-nitrobenzoic acid to solution 1, stir well to obtain solution 2, and obtain concentrated solution 2.

[0034] C. Then, prepare concentrated solution 3 by mixing pyromellitic anhydride 30-60 mg / L at 10 times the above mass concentration.

[0035] D. Take 100 ml of solutions 2 and 3 from each tank, and adjust the pH to 3.8-4.2 with acetic acid or ammonia, and keep the temperature at 38-42℃.

[0036] E. Replenishment method: For every square meter consumed, concentrate 2 and concentrate 3 need to be replenished at a ratio of 1:1, with 5ml of each of the 2 and 3 solutions added.

[0037] In this embodiment, the preparation conditions for solutions 2 and 3 are as follows: When dissolving 2-phenylimidazole in ethanol, to prevent ethanol evaporation, 50 ml / L of deionized water is added, while maintaining the room temperature not exceeding 30°C, and 2-phenylimidazole is slowly added while stirring; when dissolving 2-benzylbenzimidazole in diethylene glycol, the temperature is maintained not exceeding 35°C, 50 ml / L of deionized water is added, and 2-benzylbenzimidazole is slowly added while stirring, and then solutions 2 and 3 are mixed evenly, and water is added to the final level.

[0038] The beneficial effects of this invention are as follows: Compared with the prior art, the halogen-free organic solderable protective agent and its preparation method provided by this invention have the following advantages:

[0039] 1) This invention provides 2-phenylimidazolium as the main film-forming agent to provide the main component of the film, which is more stable than traditional imidazole film-forming agents; 2-benzylbenzimidazole is an auxiliary film-forming agent, which can improve the film layer compositeness and improve the film layer density.

[0040] 2) The methotrexate provided by the present invention is a film-forming homogenizer, which can make imidazole substances uniformly dispersed and less prone to color difference.

[0041] 3) The pyromellitic anhydride and p-nitrobenzoic acid provided by the present invention can improve the film formation rate. Compared with traditional formic acid agents containing only iron salts, the composite accelerator of this application can quickly achieve film formation without precipitation.

[0042] 4) The preparation method of the present invention is simple and soluble, very convenient to use, and the raw materials used are environmentally friendly, with low toxicity and odor, and will not cause harm to workers.

[0043] The following are several specific embodiments of the present invention.

[0044] The evaluation criteria for the experimental tests are as follows:

[0045] 1. The indicators include: 1. Color difference index: Excellent means the OSP film is glossy and free of watermarks; Good means the OSP film is slightly duller but free of watermarks; Poor means there are slight watermarks and the film layer is slightly iridescent; Poor means there is severe iridescence and obvious watermarks. 2. Film loading speed index: Excellent means film thickness is slightly 0.35-0.5 μm / min; Good means film thickness is slightly 0.2-0.35 μm / min (excluding 0.35); Poor means film thickness is slightly 0.1-0.2 μm / min (excluding 0.2); Poor means film thickness is slightly 0.1 μm / min. 3. Stability index: Excellent means a service life of 8 MTO or more; Good means a service life of 6-8 MTO (excluding 8); Poor means a service life of 4-6 MTO (excluding 6); Poor means a service life of less than 4 MTO.

[0046] Example 1

[0047] 2-Phenylidene imidazole 4 g / L, 2-benzylbenzimidazole 0.8 g / L, pyromellitic anhydride 45 mg / L, diethylene glycol 1.5 ml / L, ethanol 7.5 ml / L, p-nitrobenzoic acid 20 mg / L, methotrexate 20 mg / L, pH 4.0, balance deionized water;

[0048] Operating temperature 40℃

[0049] Time: 1 minute

[0050] in accordance with Figure 1 It can be seen that the experimental results of Example 1 are: excellent in color difference index, excellent in film loading speed index, and excellent in stability.

[0051] Example 2

[0052] 2-Phenylidene imidazole 3g / L, 2-benzylbenzimidazole 0.6g / L, pyromellitic anhydride 50mg / L, diethylene glycol 1.5ml / L, ethanol 6ml / L, p-nitrobenzoic acid 20mg / L, methotrexate 10 mg / L, pH 4.0, balance deionized water;

[0053] Operating temperature 40℃

[0054] Time: 1 minute

[0055] in accordance with Figure 1 The experimental results of Example 2 show that the color difference index is excellent, the film loading speed index is excellent, and the stability is excellent.

[0056] Example 3

[0057] 2-Phenylidene imidazole 5g / L, 2-benzylbenzimidazole 1g / L, pyromellitic anhydride 45mg / L, diethylene glycol 2ml / L, ethanol 10ml / L, p-nitrobenzoic acid 20mg / L, methotrexate 30 mg / L, pH 4.0, balance deionized water;

[0058] Operating temperature 40℃

[0059] Time: 1 minute

[0060] in accordance with Figure 1 The experimental results of Example 3 are as follows: the color difference index is excellent, the film loading speed index is excellent, and the stability is excellent.

[0061] Comparative Example 1

[0062] 2-Phenylidene imidazole 4g / L, pyromellitic anhydride 45mg / L, diethylene glycol 1.5ml / L, ethanol 7.5ml / L, p-nitrobenzoic acid 20mg / L, methotrexate 20 mg / L, pH 4.0, balance deionized water;

[0063] Operating temperature 40℃

[0064] Time: 1 minute

[0065] Comparative Example 1 lacks the auxiliary film-forming agent 2-benzylbenzimidazole compared to the Examples, based on Figure 1 The experimental results are as follows: color difference index is good, film loading speed index is good, and stability is good.

[0066] Comparative Example 2

[0067] 2-Phenylidene imidazole 4 g / L, 2-benzylbenzimidazole 0.8 g / L, pyromellitic anhydride 45 mg / L, diethylene glycol 1.5 ml / L, ethanol 7.5 ml / L, p-nitrobenzoic acid 20 mg / L, pH 4.0, balance deionized water;

[0068] Operating temperature 40℃

[0069] Time: 1 minute

[0070] Comparative Example 2 lacks the homogenizing agent methotrexate compared to the Example, based on Figure 1 The experimental results show that the color difference index is poor, the film loading speed index is excellent, and the stability index is excellent.

[0071] Comparative Example 3

[0072] 2-Phenylidene imidazole 4 g / L, 2-benzylbenzimidazole 0.8 g / L, pyromellitic anhydride 45 mg / L, diethylene glycol 1.5 ml / L, ethanol 7.5 ml / L, p-nitrobenzoic acid 20 mg / L, methotrexate 20 mg / L, pH 4.0, balance deionized water;

[0073] Operating temperature 40℃

[0074] Time: 1 minute

[0075] Comparative Example 3 lacks the accelerators pyromellitic anhydride and p-nitrobenzoic acid compared to the Examples. Figure 1 The experimental results show that the color difference index is excellent, the film loading speed index is poor, and the stability index is excellent.

Claims

1. A halogen-free organic solderable protective agent, characterized in that, The product contains the following components at the following concentrations: 2-phenylimidazole 2.5-5 g / L, 2-benzylbenzimidazole 0.5-1.0 g / L, pyromellitic anhydride 30-60 mg / L, diethylene glycol 1-2 ml / L, ethanol 5-10 ml / L, p-nitrobenzoic acid 10-30 mg / L, and methotrexate 10-30 mg / L. The temperature is 35-45℃, and the pH is controlled between 3.8 and 4.

2. The remainder is deionized water. The 2-phenylimidazole is used as the main film-forming agent, and the pH adjusters are acetic acid and ammonia.

2. The halogen-free organic solderable protective agent according to claim 1, characterized in that... The 2-benzylbenzimidazole is an auxiliary film-forming agent.

3. The halogen-free organic solderable protective agent according to claim 1, characterized in that, The methotrexate is a film-forming homogenizer.

4. The halogen-free organic solderable protective agent according to claim 1, characterized in that, The pyromellitic anhydride and p-nitrobenzoic acid can improve the film formation rate.

5. The halogen-free organic solderable protective agent according to claim 1, characterized in that, The diethylene glycol and ethanol provide organic solvents, increasing solubility.

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