Environment-friendly low-temperature soldering paste and preparation method thereof

Abstract

The application relates to the field of soldering paste preparation, and particularly discloses an environment-friendly low-temperature soldering paste and a preparation method thereof. The environment-friendly low-temperature soldering paste comprises the following raw materials in percentage by weight: 76-82% of tin powder, 14-17% of a soldering flux, 3-5% of an active agent and 1-2% of an environment-friendly additive; the environment-friendly additive is glycidyl ether modified diatomite; and the preparation method of the glycidyl ether modified diatomite comprises the following steps: S1, diatomite pretreatment: diatomite is calcined at high temperature, ground, and filtered through a 300-mesh sieve to obtain pretreated diatomite; and S2, glycidyl ether modification: the pretreated diatomite is dispersed in an ethanol solution, glycidyl ether is added, mixed and stirred, and then filtered, washed and dried to obtain the glycidyl ether modified diatomite. The soldering paste prepared by the application can realize low-temperature welding, has superior environmental protection performance and low harmful substance content.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of soldering paste preparation, in particular to an environment-friendly low-temperature soldering paste and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the electronic industry, soldering paste, as an important material in the electronic welding process, has an important influence on the quality and reliability of electronic products. However, traditional soldering paste usually needs to be welded at high temperature, which not only has high energy consumption but also easily causes thermal damage to electronic components. In addition, traditional soldering paste often contains harmful substances, which poses a potential threat to the environment and human health.

[0003] In order to solve the above problems, in recent years, low-temperature soldering paste has gradually attracted attention. Low-temperature soldering paste can be welded at a lower temperature, thereby reducing energy consumption and reducing thermal damage to electronic components. However, the existing low-temperature soldering paste still has deficiencies in environmental performance, such as high content of harmful substances, which cannot meet the increasingly stringent environmental requirements. SUMMARY

[0004] In order to solve at least one of the above technical problems, a low-temperature soldering paste with low content of harmful substances is developed, and the application provides an environment-friendly low-temperature soldering paste and a preparation method thereof.

[0005] On the one hand, the application provides an environment-friendly low-temperature soldering paste, which comprises the following raw materials in percentage by weight: tin powder 76-82%, flux 14-17%, active agent 3-5%, and environment-friendly additive 1-2%.

[0006] The environment-friendly additive is glycidyl ether modified diatomite.

[0007] The preparation method of the glycidyl ether modified diatomite comprises the following steps:

[0008] S1, diatomite pretreatment: diatomite is calcined at 700-800 DEG C for 2-4 h, ground, and sieved through a 300-mesh sieve to obtain pretreated diatomite;

[0009] S2, glycidyl ether modification: the pretreated diatomite is dispersed in an ethanol solution, and then glycidyl ether is added, and after stirring at 60-80 DEG C for 6-9 h, the glycidyl ether modified diatomite is obtained by filtering, washing and drying.

[0010] By adopting the above technical scheme, the raw materials and the ratio adopted by the application are used to prepare the environment-friendly low-temperature soldering paste, which has excellent comprehensive performance, can realize low-temperature welding, and has excellent environmental performance and low content of harmful substances.

[0011] The modified diatomite added in the soldering paste can help absorb the moisture in the soldering paste, reduce bubbles and splashes during the soldering process. Moreover, the glycidyl ether modified diatomite can adsorb harmful gases generated by the decomposition of the flux in the soldering paste, which helps to reduce the smoke and harmful substances generated during the soldering process, and improves the safety of the working environment.

[0012] Optionally, in the step S2, the weight ratio of the pretreated diatomite and the glycidyl ether is (5-10):1.

[0013] Optionally, the tin powder is composed of the following components by weight percentage: 5-10% Ni, 0.1-1% Ag, 25-30% Bi, and the balance of Sn.

[0014] By adopting the above technical solution, the application limits the proportion of each component of the tin powder, a small amount of Ag can improve the oxidation resistance of the tin-based alloy powder, improve the storage stability of the soldering paste, and also improve the tensile strength of the solder and enhance the welding quality.

[0015] Optionally, the flux includes the following components by weight parts: 20-35 parts of rosin, 28-40 parts of solvent, 1-3 parts of antioxidant, 1-3 parts of corrosion inhibitor, and 2-5 parts of thixotropic agent.

[0016] Optionally, the active agent is adipic acid, oxalic acid, and dodecanedioic acid in a weight ratio of (4-6):(1-3):1.

[0017] By adopting the above technical solution, the application selects adipic acid, oxalic acid, and dodecanedioic acid for compounding as the active agent, which can effectively shorten the wetting time of the solder and improve the wetting ability for the soldering substrate, and can be fully volatilized and decomposed at the soldering temperature without residue.

[0018] Optionally, the rosin is a mixture of perhydrogenated rosin and water white hydrogenated rosin in a weight ratio of 1:(7.3-9.6).

[0019] By adopting the above technical solution, the application selects perhydrogenated rosin and water white hydrogenated rosin and limits their ratio for compounding. The perhydrogenated rosin can ensure activity, and the water white hydrogenated rosin can improve thermal stability, reduce smoke, improve residual discoloration, and also form a film to prevent secondary oxidation during soldering.

[0020] Optionally, the solvent is a mixture of diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol in a weight ratio of 1:(1-3).

[0021] Optionally, the antioxidant is hydroquinone.

[0022] Optionally, the corrosion inhibitor is benzotriazole.

[0023] In a second aspect, the application provides a preparation method of the environmentally friendly low-temperature soldering paste, comprising the following steps: mixing rosin, a solvent, a corrosion inhibitor, an antioxidant and a thixotropic agent, heating and dissolving, stirring, and cooling to obtain a flux, and finally stirring the tin powder, the flux, the active agent and the environmentally friendly additive under nitrogen protection to obtain the environmentally friendly low-temperature soldering paste.

[0024] By adopting the technical scheme, the preparation method of the environmentally friendly low-temperature soldering paste is simple in operation, can be produced industrially, and the prepared soldering paste has good welding performance and is green and environmentally friendly, and has excellent comprehensive performance.

[0025] In summary, the application has at least one of the following beneficial technical effects:

[0026] 1. The raw materials and the ratio adopted by the application have excellent comprehensive performance of the prepared environmentally friendly low-temperature soldering paste, can realize low-temperature welding, and have excellent environmental performance and low harmful substance content. The addition of modified diatomite in the soldering paste can help absorb the moisture in the soldering paste, reduce bubbles and splashes in the welding process. Moreover, the glycidyl ether modified diatomite can adsorb harmful gases generated by the decomposition of the flux in the soldering paste, which helps to reduce the smoke and harmful substances generated in the welding process and improve the safety of the working environment.

[0027] 2. The application limits the proportion of each component of the tin powder, and a small amount of Ag can improve the oxidation resistance of the tin-based alloy powder, improve the storage stability of the soldering paste, and also improve the tensile strength of the solder and enhance the welding quality. The application selects adipic acid, oxalic acid and dodecanedioic acid for compounding as an active agent, which can effectively shorten the wetting time of the solder and improve the wetting ability of the solder on the welding substrate, and can fully volatilize and decompose at the welding temperature without residue. The application selects fully hydrogenated rosin and water white hydrogenated rosin and limits the proportion of the two for compounding. The fully hydrogenated rosin can ensure activity, the water white hydrogenated rosin can improve thermal stability, reduce smoke, improve the discoloration condition of residue, and also form a film to prevent secondary oxidation during welding.

[0028] 3. The preparation method of the environmentally friendly low-temperature soldering paste is simple in operation, can be produced industrially, and the prepared soldering paste has good welding performance and is green and environmentally friendly, and has excellent comprehensive performance. DETAILED DESCRIPTION

[0029] The application will be further described in detail below in combination with embodiments.

[0030] The application designs an environmentally friendly low-temperature soldering paste, which comprises the following raw materials in percentage by weight: 76-82% of tin powder, 14-17% of flux, 3-5% of active agent, and 1-2% of environmentally friendly additive.

[0031] The environmentally friendly additive is glycidyl ether modified diatomite.

[0032] The preparation method of the glycidyl ether modified diatomite comprises the following steps:

[0033] S1, diatomite pretreatment: diatomite is calcined at high temperature of 700-800℃ for 2-4h, ground, and sieved through a 300 mesh sieve to obtain pretreated diatomite;

[0034] S2, glycidyl ether modification: the pretreated diatomite is dispersed in an ethanol solution, glycidyl ether is added, and after stirring at 60-80℃ for 6-9h, filtration, washing, and drying are performed to obtain the glycidyl ether modified diatomite.

[0035] A preparation method of an environmentally friendly low-temperature soldering tin paste comprises the following steps: mixing rosin, solvent, corrosion inhibitor, antioxidant, and thixotropic agent, heating and dissolving, stirring, and cooling to obtain a flux, and finally stirring tin powder, the flux, an active agent, and an environmentally friendly additive under nitrogen protection to obtain the environmentally friendly low-temperature soldering tin paste.

[0036] The raw materials and the ratio used in the present application, the raw materials and the ratio used in the present application, the prepared environmentally friendly low-temperature soldering tin paste has excellent comprehensive performance, can realize low-temperature welding, and has excellent environmental performance and low harmful substance content. Adding modified diatomite in the soldering tin paste can help absorb the moisture in the soldering tin paste, reduce bubbles and splashing in the welding process. Moreover, the glycidyl ether modified diatomite can adsorb harmful gases generated by the decomposition of the flux in the soldering tin paste, which helps to reduce the smoke and harmful substances generated in the welding process, and improves the safety of the working environment. The preparation method of the environmentally friendly low-temperature soldering tin paste of the present application is simple to operate and can be industrialized, and the prepared soldering tin paste has good welding performance and is green and environmentally friendly, and has excellent comprehensive performance. Specific embodiments

[0038] Preparation Example 1-3

[0039] Preparation Example 1

[0040] The present preparation example provides a glycidyl ether modified diatomite, and a preparation method thereof comprises the following steps:

[0041] S1, diatomite pretreatment: diatomite is calcined at high temperature of 700℃ for 4h, ground, and sieved through a 300 mesh sieve to obtain pretreated diatomite;

[0042] S2, glycidyl ether modification: the pretreated diatomite is dispersed in an ethanol solution, glycidyl ether is added, and after stirring at 60℃ for 9h, filtration, washing, and drying are performed to obtain the glycidyl ether modified diatomite.

[0043] In step S2, the weight ratio of the pretreated diatomite to the glycidyl ether is 5:1.

[0044] Preparation Example 2

[0045] The preparation example provides a glycidyl ether modified diatomite, and a preparation method thereof comprises the following steps:

[0046] S1, diatomite pretreatment: diatomite is calcined at 740 DEG C for 3h, ground, and sieved through a 300 mesh sieve to obtain pretreated diatomite;

[0047] S2, glycidyl ether modification: the pretreated diatomite is dispersed in an ethanol solution, and glycidyl ether is added, and after stirring at 70 DEG C for 8h, filtration, washing and drying are performed to obtain the glycidyl ether modified diatomite.

[0048] In step S2, the weight ratio of the pretreated diatomite and the glycidyl ether is 8:1.

[0049] Preparation Example 3

[0050] The preparation example provides a glycidyl ether modified diatomite, and a preparation method thereof comprises the following steps:

[0051] S1, diatomite pretreatment: diatomite is calcined at 800 DEG C for 2h, ground, and sieved through a 300 mesh sieve to obtain pretreated diatomite;

[0052] S2, glycidyl ether modification: the pretreated diatomite is dispersed in an ethanol solution, and glycidyl ether is added, and after stirring at 80 DEG C for 6h, filtration, washing and drying are performed to obtain the glycidyl ether modified diatomite.

[0053] In step S2, the weight ratio of the pretreated diatomite and the glycidyl ether is 10:1.

[0054] Examples 1-3

[0055] Example 1

[0056] An environment-friendly low-temperature soldering paste comprises the following raw materials in percentage by weight: 80% of tin powder, 15% of flux, 4% of active agent, and 1% of environment-friendly additive;

[0057] The environment-friendly additive is the glycidyl ether modified diatomite prepared in Preparation Example 1;

[0058] The tin powder is composed of the following components in percentage by weight: 5% of Ni, 0.6% of Ag, 27% of Bi, and the balance of Sn;

[0059] The flux comprises the following components in parts by weight: 27 parts of rosin, 35 parts of solvent, 2 parts of antioxidant, 2 parts of corrosion inhibitor, and 3 parts of thixotropic agent;

[0060] The active agent is adipic acid, oxalic acid and dodecanedioic acid in a weight ratio of 4:1:1;

[0061] Rosin is a mixture of fully hydrogenated rosin and water white hydrogenated rosin at a weight ratio of 1:7.3;

[0062] Solvent is a mixture of diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol at a weight ratio of 1:1;

[0063] Antioxidant is hydroquinone, corrosion inhibitor is benzotriazole, and thixotropic agent is erucic acid amide.

[0064] Example 2

[0065] An environmentally friendly low-temperature soldering paste comprises the following raw materials by weight percentage: tin powder 76%, flux 17%, active agent 5%, and environmentally friendly additive 2%;

[0066] The environmentally friendly additive is glycidyl ether modified diatomite prepared in Preparation Example 1;

[0067] The tin powder is composed of the following components by weight percentage: 5% Ni, 0.1% Ag, 25% Bi, and the balance of Sn;

[0068] The flux comprises the following components by weight: rosin 20 parts, solvent 28 parts, antioxidant 1 part, corrosion inhibitor 1 part, and thixotropic agent 2 parts;

[0069] The active agent is a mixture of adipic acid, oxalic acid and dodecanedioic acid at a weight ratio of 4:1:1;

[0070] Rosin is a mixture of fully hydrogenated rosin and water white hydrogenated rosin at a weight ratio of 1:7.3;

[0071] Solvent is a mixture of diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol at a weight ratio of 1:1;

[0072] Antioxidant is hydroquinone, corrosion inhibitor is benzotriazole, and thixotropic agent is erucic acid amide.

[0073] Example 3

[0074] An environmentally friendly low-temperature soldering paste comprises the following raw materials by weight percentage: tin powder 82%, flux 14%, active agent 3%, and environmentally friendly additive 1%;

[0075] The environmentally friendly additive is glycidyl ether modified diatomite prepared in Preparation Example 1;

[0076] The tin powder is composed of the following components by weight percentage: 10% Ni, 1% Ag, 30% Bi, and the balance of Sn;

[0077] The flux comprises the following components by weight: rosin 35 parts, solvent 40 parts, antioxidant 3 parts, corrosion inhibitor 3 parts, and thixotropic agent 5 parts;

[0078] The active agent is adipic acid, oxalic acid and dodecanedioic acid in a weight ratio of 4:1:1;

[0079] The rosin is a mixture of perhydrogenated rosin and water white hydrogenated rosin in a weight ratio of 1:7.3;

[0080] The solvent is diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol in a weight ratio of 1:1;

[0081] The antioxidant is hydroquinone, the corrosion inhibitor is benzotriazole, and the thixotropic agent is erucic acid amide.

[0082] The preparation method of the environmentally friendly low-temperature soldering paste of Examples 1-3 comprises the following steps: mixing rosin, solvent, corrosion inhibitor, antioxidant and thixotropic agent, heating and dissolving, stirring, and cooling to obtain a flux, and finally stirring the tin powder, flux, active agent and environmentally friendly additive under nitrogen protection to obtain an environmentally friendly low-temperature soldering paste.

[0083] Comparative Example 1

[0084] Comparative Example 1 differs from Example 1 in that glycidyl ether modified diatomite is not added, and the rest of the components and the preparation method are consistent with Example 1.

[0085] Comparative Example 2

[0086] Comparative Example 2 differs from Example 1 in that the tin powder does not contain Ag, and the rest of the components and the preparation method are consistent with Example 1.

[0087] Example 4

[0088] Example 4 differs from Example 1 in that the environmentally friendly additive in this example is the glycidyl ether modified diatomite prepared in Preparation Example 2, and the rest of the components and the preparation method are consistent with Example 1.

[0089] Example 5

[0090] Example 5 differs from Example 1 in that the environmentally friendly additive in this example is the glycidyl ether modified diatomite prepared in Preparation Example 3, and the rest of the components and the preparation method are consistent with Example 1.

[0091] Example 6

[0092] Example 6 differs from Example 4 in that the weight ratio of perhydrogenated rosin and water white hydrogenated rosin is 1:8, and the rest of the components and the preparation method are consistent with Example 1.

[0093] Example 7

[0094] Example 7 differs from Example 4 in that the weight ratio of perhydrogenated rosin and water white hydrogenated rosin is 1:9.6, and the rest of the components and the preparation method are consistent with Example 1.

[0095] Example 8

[0096] Example 8 differs from Example 6 in that the weight ratio of adipic acid, oxalic acid and dodecanedioic acid is 5:2:1, and the rest of the components and the preparation method are consistent with Example 1.

[0097] Example 9

[0098] Example 9 differs from Example 6 in that the weight ratio of adipic acid, oxalic acid and dodecanedioic acid is 6:3:1, and the rest of the components and the preparation method are consistent with Example 1.

[0099] Example 10

[0100] Example 10 differs from Example 8 in that the weight ratio of diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol is 1:2, and the rest of the components and the preparation method are consistent with Example 1.

[0101] Example 11

[0102] Example 11 differs from Example 8 in that the weight ratio of diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol is 1:3, and the rest of the components and the preparation method are consistent with Example 1.

[0103] Experimental detection

[0104] Detection items and detection methods

[0105] 1. Tensile strength: according to GB / T 2651-2023 standard.

[0106] 2. Appearance of solder joint: print the solder paste prepared in the example, and observe the appearance of the solder joint to see if there are black spots and residues.

[0107] 3. Welding quality: the welding quality can be shown by the quality of the solder joint, and the test of the quality of the solder joint can be tested by the solder ball test. According to the degree of aggregation of the solder bead, it is divided into 4 grades, grade 1 requires no tin bead, only one large tin ball; Grade 2 requires no more than 3 tin beads around the large ball, and the tin bead size is not greater than 75 microns; Grade 3 can have more than 3 tin beads around the ball but not aggregated and not forming a ring, and the tin bead size is not greater than 75 microns; Grade 4 has many tin beads in addition to the large spherical shape, and forms a discontinuous ring. Grade 1 and Grade 2 are excellent, Grade 3 is pass, and Grade 4 is fail.

[0108] Detection results

[0109] The experimental detection results are shown in Table 1.

[0110] Table 1

[0111] Tensile strength / MPa Weld appearance Weld quality Example 1 86 No black spots, no residues Class 1 Example 2 79 No black spots, no residues Class 2 Example 3 82 No black spots, no residues Class 2 Comparative Example 1 70 Black spots, few residues Class 3 Comparative Example 2 57 No black spots, no residues Class 4 Example 4 88 No black spots, no residues Class 1 Example 5 86 No black spots, no residues Class 1 Example 6 91 No black spots, no residues Class 1 Example 7 89 No black spots, no residues Class 1 Example 8 94 No black spots, no residues Class 1 Example 9 90 No black spots, no residues Class 1 Example 10 96 No black spots, no residues Class 1 Example 11 92 No black spots, no residues Class 1

[0112] Result analysis

[0113] In combination with Examples 1-3, Comparative Examples 1-2 and Table 1, it can be seen that the solder paste prepared by using the solder paste formulation of the present application has good welding quality at low temperature welding, and when halogen-free components are used for green and environmentally friendly welding operation, the generation of smoke and harmful substances can be effectively inhibited, and the working environment of the operators is ensured.

[0114] In combination with Examples 1, Examples 4-5 and Table 1, it can be seen that the solder paste prepared by using the glycidyl ether modified diatomite prepared in Preparation Example 2 has better comprehensive quality.

[0115] In combination with Examples 4, Examples 4-7 and Table 1, it can be seen that when the weight ratio of hydrogenated rosin and water white hydrogenated rosin is 1:8, the solder paste prepared has better comprehensive quality.

[0116] In combination with Examples 6, Examples 8-9 and Table 1, it can be seen that when the active agent is adipic acid, oxalic acid and dodecanedioic acid with a weight ratio of 5:2:1, the solder paste prepared has better comprehensive quality.

[0117] In combination with Examples 8, Examples 10-11 and Table 1, it can be seen that when the solvent is diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol with a weight ratio of 1:2, the solder paste prepared has better comprehensive quality.

[0118] The above are preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: any equivalent changes made in accordance with the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. An environmentally friendly low-temperature solder paste, characterized by, The soldering tin paste comprises the following raw materials by weight percentage: tin powder 76-82%, flux 14-17%, active agent 3-5%, and environment-friendly additive 1-2%; the environment-friendly additive is glycidyl ether modified diatomite; the preparation method of the glycidyl ether modified diatomite comprises the following steps: S1, diatomite pretreatment: diatomite is calcined at 700-800 ℃ for 2-4 h, ground, and sieved through a 300-mesh sieve to obtain pretreated diatomite; S2, glycidyl ether modification: the pretreated diatomite is dispersed in an ethanol solution, glycidyl ether is added, and after stirring at 60-80 ℃ for 6-9 h, the glycidyl ether modified diatomite is obtained by filtration, washing, and drying. The tin powder is composed of the following components by weight percentage: 5-10% Ni, 0.1-1% Ag, 25-30% Bi, and the balance of Sn.

2. The environmentally friendly low-temperature solder paste according to claim 1, characterized in that, In the step S2, the weight ratio of the pretreated diatomite to the glycidyl ether is (5-10):

1.

3. The environmentally friendly low-temperature solder paste according to claim 1, characterized in that, The flux comprises the following components by weight parts: rosin 20-35 parts, solvent 28-40 parts, antioxidant 1-3 parts, corrosion inhibitor 1-3 parts, and thixotropic agent 2-5 parts.

4. The environmentally friendly low-temperature solder paste according to claim 1, characterized in that, The active agent is a mixture of adipic acid, oxalic acid and dodecanedioic acid in a weight ratio of (4-6):(1-3):

1.

5. The environmentally friendly low-temperature solder paste according to claim 3, characterized in that, The rosin is fully hydrogenated rosin and water white hydrogenated rosin, and the weight ratio of the fully hydrogenated rosin to the water white hydrogenated rosin is 1:(7.3-9.6).

6. The environmentally friendly low-temperature solder paste according to claim 3, characterized in that, The solvent is a mixture of diethylene glycol monooctyl ether and 2-methyl-2,4-pentanediol in a weight ratio of 1:(1-3).

7. The environmentally friendly low-temperature solder paste according to claim 3, characterized in that, The antioxidant is hydroquinone.

8. The environmentally friendly low-temperature solder paste according to claim 3, characterized in that, The corrosion inhibitor is benzotriazole.

9. A method for preparing the environmentally friendly low-temperature solder paste according to any one of claims 1-8, characterized in that, The method comprises the following steps: mixing rosin, solvent, corrosion inhibitor, antioxidant and thixotropic agent, heating and dissolving, stirring, and cooling to obtain the flux; and finally, stirring the tin powder, flux, active agent and environment-friendly additive under nitrogen protection to obtain the environment-friendly low-temperature soldering tin paste.