Low-silver lead-free flux paste and preparation method thereof

A technology of flux paste and active auxiliary agent, applied in welding equipment, welding medium, manufacturing tools, etc., can solve the problems of low surface insulation resistance, shortened template life, easy to produce solder balls, etc., to achieve high surface insulation resistance, improve Template life, the effect of not easy to short circuit

Active Publication Date: 2013-07-31
昆山成利焊锡制造有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, low-silver solder Sn99 / Ag0.3 / Cu0.7 has been developed while maintaining soldering reliability. However, when high-silver lead-free solder paste is used to prepare low-silver solder paste, due to insufficient activity, solder balls are easily generated and the surface is insulated. Low resistance, shortened stencil life

Method used

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  • Low-silver lead-free flux paste and preparation method thereof
  • Low-silver lead-free flux paste and preparation method thereof
  • Low-silver lead-free flux paste and preparation method thereof

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Embodiment Construction

[0022] The present invention will be further described in detail below in conjunction with specific embodiments. See Table 1 for specific examples. The solder paste prepared by using the lead-free flux paste and solder powder of the technical scheme of the present invention is composed of 85-91wt.% solder powder and 9-15wt.% flux paste, preferably 11.5% by weight. In the example, the low-silver lead-free solder paste and 88.5 wt.% tin powder were prepared into a solder paste and the lead-free solder paste sold in the market was used for a comparative test. The composition of the tin powder was 99Sn / 0.3Ag / 0.7Cu.

[0023] Table 1 Specific Examples

[0024]

[0025] Refer to the method of ICP TM 6502.4.43 to test the tin balls and observe the condition of the tin balls on the alumina test board; refer to the method of ICP TM 6502.6.3.3B to measure the surface insulation resistance; refer to the method of ICP TM 6502.4.45 to measure the wettability.

[0026] Print on the automatic prin...

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Abstract

The invention discloses a low-silver lead-free flux paste, which comprises abietic resin 20-50wt.%, a thixotropic agent 1-10 wt.%, a stabilizing agent 1-5 wt.%, active adjuvant 1-10 wt.%, an active agent 5-20 wt.%, and the balance solvent. The stabilizing agent is poly-alpha-olefin with ultrahigh branches, the number-average molecular weight is 2800-2900, the distribution index of degree of polymerization is 1.6-1.7, and the viscosity measured at the temperature of under 37.8 DEG C according to American Society for Testing and Materials (MSTM) D-3236 is 530cP. The active agent is long-chain linear carboxylic acid which contains 26-50 carbon atoms, the acid value is 61-115mgKOH / g, and the number-average molecular weight is 390-720. The active adjuvant is hydroxy carbazole. The flux paste and lead-free flux paste with low-silver lead-free materials can be prepared into the lead-free flux paste which has small solder balls, good welding effects and high surface insulating resistance so that a short circuit does not happen to a circuit board after welding, wettability is good, welding spots are full, and welding effects are good. In addition, corrosivity is small, and service life of a template is greatly improved. Besides, the preparation method of the flux paste is simple and easy to implement in industries in a large-scale mode.

Description

Technical field [0001] The invention relates to a soldering paste for the electronics industry, in particular to a low-silver lead-free soldering paste for the electronics industry and a preparation method thereof. The soldering paste is suitable for use with low-silver solder. Background technique [0002] With the increase of people’s awareness of environmental protection, environmental protection laws and regulations have become more perfect and strict. Although traditional tin-lead solder paste has the advantages of excellent wettability, solderability, good mechanical properties and low prices, the lead content in it is relatively high. High, it will endanger human health and pollute the environment. Therefore, lead-free solder paste soldering technology has replaced traditional soldering technology in the electronics industry. Lead-free solder paste has been widely used as a pollution-free soldering material in the communications electronics industry, such as electronic ass...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K35/363
Inventor 苏传猛苏明斌苏传港苏燕旋邓勇何繁丽晏和刚
Owner 昆山成利焊锡制造有限公司
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