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Unleaded halogen-free soldering paste with high wettability

A solder paste and wettability technology, applied in the field of fluxing chemicals for electronic assembly, can solve the problem of low welding activity, achieve low post-weld corrosion, good wettability and storage stability, and reduce post-weld corrosion Effect

Inactive Publication Date: 2011-05-25
SICHUAN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the above-mentioned compound salt is still decomposed into the original organic acid and organic amine at the welding temperature, its welding activity is still far lower than that of the hydrohalide salt of organic amine.

Method used

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  • Unleaded halogen-free soldering paste with high wettability
  • Unleaded halogen-free soldering paste with high wettability
  • Unleaded halogen-free soldering paste with high wettability

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] In this embodiment, the solder alloy powder is Sn96.5Ag3.0Cu0.5, its content is 89% (mass percentage), and the content of flux is 11% (mass percentage).

[0063] The components and contents of the flux are as follows:

[0064] Resin Specially modified disproportionated rosin 19.0% of flux mass

[0065] Acrylic modified rosin 32.0% of flux mass

[0066] Thixotropic agent Hydrogenated castor oil 5.0% of flux mass

[0067] Activator Tyrosine benzyl ester p-toluenesulfonate 0.05% by mass of flux

[0068] Solvent diethylene glycol monohexyl ether 43.95% of flux mass

[0069] The above-mentioned solder alloy powder and flux are thoroughly mixed to prepare a solder paste, and the product should be kept refrigerated at 0-10°C. Under the welding and damp heat test conditions as described in Comparative Example 1, the welding pads in Example 1 are full and full after welding, and have excellent wetting; the comparison pictures before and after cleaning through the dam...

Embodiment 2

[0071] In this embodiment, the solder alloy powder is Sn96.5Ag3.0Cu0.5, its content is 89% (mass percentage), and the content of flux is 11% (mass percentage).

[0072] The components and contents of the flux are as follows:

[0073] Resin Specially modified disproportionated rosin 19.0% of flux mass

[0074] Acrylic modified rosin 35.0% of flux mass

[0075] Thixotropic agent Hydrogenated castor oil 5.0% of flux mass

[0076] Active agent Benzyl valine ester p-toluenesulfonate 10.0% by mass of flux

[0077] Solvent diethylene glycol monohexyl ether 31.0% of flux mass

[0078] The above-mentioned solder alloy powder and flux are thoroughly mixed to prepare a solder paste, and the product should be kept refrigerated at 0-10°C. Under the welding and damp heat test conditions as described in Comparative Example 1, the solder joints in Example 2 are not full after welding, and there are a small amount of scattered tin beads; the comparison pictures before and after cle...

Embodiment 3

[0080] In this embodiment, the solder alloy powder is Sn99Ag0.3Cu0.7, its content is 89% (mass percentage), and the content of solder is 11% (mass percentage).

[0081] The components and contents of the flux are as follows:

[0082] Resin Specially modified disproportionated rosin 19.0% of flux mass

[0083] Acrylic modified rosin 35.0% of flux mass

[0084] Thixotropic agent Hydrogenated castor oil 7.0% of flux mass

[0085] Activator Leucine ethyl ester p-toluenesulfonate 3.5% by mass of flux

[0086] Solvent Diethylene glycol monohexyl ether 35.5% of flux mass

[0087] The above-mentioned solder alloy powder and flux are thoroughly mixed to prepare a solder paste, and the product should be kept refrigerated at 0-10°C. Under the soldering and damp heat test conditions as described in Comparative Example 1, the welding pads in Example 3 are regular, but the solder joints are not full; the comparison pictures before and after cleaning through the damp heat test ( ...

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Abstract

The invention relates to a soldering assistant chemical used for electronic assembly, in particular to an unleaded halogen-free soldering paste in the field of brazing material used for electronic surface assembly, which consists of 80-93 percent by weight of solder alloy powder and 7-20 percent by weight of flux, wherein the solder alloy powder is unleaded alloy, and the flux comprises 30-55 percent by weight of resin, 20-50 percent by weight of solvent, 1-8 percent by weight of thixotropic agent and 0.01-20 percent by weight of active agent, and the active agent comprises amino acid p-toluenesulfonic acid salt and / or amino-acid ester p-toluenesulfonic acid salt. The soldering paste has higher wettability, reduces corrosivity, has good storage stability, is unleaded and halogen-free, meets the requirement of environmental protection, and can be applied to the electronic industry.

Description

technical field [0001] The patent of the present invention relates to flux chemicals for electronic assembly, in particular to lead-free and halogen-free solder paste used in the field of soldering materials for electronic surface assembly. Background technique [0002] With the rapid development of science and technology, electronic products are developing toward integration, digitization, and miniaturization, and surface mount technology (SMT) has become the mainstream technology for electronic surface mount. The role of solder paste in the SMT process is to temporarily adhere surface-mounted electronic components to a certain position on the circuit board; remove solder alloy powder and oxides on the surface of the pad; prevent re-oxidation of solder joints; make surface-mounted components The pins or end connectors are connected to the substrate to complete the entire soldering. [0003] Solder paste is a uniform paste mixture with certain viscosity and good thixotropy,...

Claims

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Application Information

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IPC IPC(8): B23K35/22B23K35/363
Inventor 黄艳杨道宾张占元陈群卢志云邓小成郑伟民
Owner SICHUAN UNIV
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