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No-clean flux for low-silver lead-free solder and preparation method thereof

A technology of lead-free solder and flux, applied in welding equipment, welding medium, manufacturing tools, etc., can solve the problems of poor soldering effect of low-silver lead-free solder, polluting the environment, low solid content, etc., and achieves non-irritating Strong smell, long storage time, mild effect of brazing process

Active Publication Date: 2017-07-07
CHONGQING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The object of the present invention is to provide a low solid content, high activity, no-cleaning flux for low-silver lead-free solder, no shrinkage after welding, stable properties, long storage time, mild brazing process, less chemical smog, Solve the shortcomings of the current existing fluxes such as large residues after soldering, severe corrosion, poor fluxing effect on low-silver lead-free solders, and environmental pollution, so that the application of low-silver lead-free solders is more extensive

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0038] The preparation method of the no-cleaning flux for the low-silver lead-free solder of the present invention, the preparation process of the flux comprises the following steps:

[0039]The first step: add the rosin of the film-forming agent into the organic solvent in a certain proportion, heat and stir at a temperature of 30°C to 70°C until it is completely dissolved; the second step: add the active agent to the solution obtained in step 1 in sequence, Heating at a temperature of 30° C. to 70° C. to promote dissolution; Step 3: Finally, add surfactants, antioxidants, and corrosion inhibitors to the solution obtained in Step 2, and stir to dissolve with residual heat. After mixing evenly, filter to obtain the flux, or filter after standing still.

Embodiment 1

[0041] In this example, the raw materials are prepared according to the following weight ratio: elaidic acid: adipic acid: glutaric acid = 2: 3: 3, elaidic acid + adipic acid + glutaric acid = 3%, diethanolamine is 0.5%, the surface The active agent OP-10 is 0.2%, the film forming agent (hydrogenated rosin) is 1%, the antioxidant hydroquinone is 0.3%, the corrosion inhibitor benzotriazole is 0.1%, and the balance is solvent, which is isopropyl A mixture of alcohol and diethylene glycol in a weight ratio of 1:9.

[0042] When preparing, add rosin as a film-forming agent into the solvent according to the proportion required by the process, heat and stir at a temperature of 30°C to 70°C until it is completely dissolved; add the active agent to the solution, and heat at a temperature of 30°C to 70°C to promote dissolution; finally, add surfactant, antioxidant and corrosion inhibitor to the solution obtained in the second step, stir and dissolve with residual heat; after mixing eve...

Embodiment 2

[0044] In this example, raw materials are prepared according to the following weight ratio: elaidic acid: adipic acid: oxalic acid: glutaric acid = 5:6:6:6, elaidic acid + adipic acid + oxalic acid + glutaric acid = 5%, two Ethanolamine is 0.8%, surfactant OP-10 is 0.4%, film-forming agent (hydrogenated rosin:polymerized rosin=1:2) is 1.2%, antioxidant hydroquinone is 0.4%, corrosion inhibitor benzotriazepam azole is 0.4%, and the balance is solvent, which is a mixture of isopropanol and triethylene glycol in a weight ratio of 3:17.

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PUM

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Abstract

The invention relates to a non-cleaning flux for a low-silver lead-free brazing filler metal and a preparation method of the non-cleaning flux. The flux is prepared from such component in percentage by weight as 3%-10% of active agent, 0.2%-2% of surfactant, 1%-5% of film-forming agent, 0.1%-1.5% of antioxidant, 0.1%-1.5% of corrosion inhibitor and the balance of solvent, and the total weight percentage of all the components is 100%. The non-cleaning flux for the low-silver lead-free brazing filler metal is low in cost, simple in preparation process, free from halogens, non-toxic, free from pungent smell, stable in chemical properties, and long in storage time; in addition, the non-cleaning flux is low in solid content, mild in brazing process, low in chemical smoke, and extremely low in postwelding residue, and therefore, the corrosion to a circuit board can be greatly reduced; furthermore, the non-cleaning flux is good in wettability, the welding spot has no shrinkage and solder blasting, the surface of the welding spot is bright and clean, and no postwelding cleaning step is needed.

Description

technical field [0001] The invention relates to a flux for lead-free solder, in particular to a no-clean flux for low-silver lead-free solder and a preparation method thereof. This flux is suitable for Sn-0.3Ag-0.7Cu, especially low-silver hypoeutectic Sn-0.45Ag-0.68Cu lead-free solder products. Background technique [0002] The eutectic or near-eutectic Sn-3.0Ag-0.5Cu (SAC305) solder is undoubtedly a lead-free solder that is recognized at home and abroad in terms of performance and is equivalent to the traditional SnPb eutectic solder. However, with the increase in the price of metal raw materials, the cost of solder has increased significantly. Moreover, with the development of electronic products towards ultra-large-scale integration, digitization, and miniaturization, and the increasingly fierce market competition, the development of low-cost, high-performance low-silver SAC lead-free solder alloys has become an urgent need for the electronic packaging industry. [000...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K35/363B23K35/40
CPCB23K35/3612B23K35/40
Inventor 甘贵生孟国奇杜长华杨栋华刘鲁亭许洁刘昭伟朱晓隆
Owner CHONGQING UNIV OF TECH