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Lead free tin cream and preparation process

A lead-free solder paste and tin oil technology, used in manufacturing tools, welding equipment, metal processing equipment, etc., can solve the problems of corrosiveness, deep color residue, easy splashing, etc., to achieve less residue after welding, surface Good activity, good slow-drying effect

Inactive Publication Date: 2006-07-19
倪潮春
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  • Summary
  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0003] The existing lead-free solder paste is generally used for soldering electronic products. It is composed of solder powder and flux. It has no moderate viscosity, no good diffusivity and bonding, and the adhesion and printability are not very ideal. After printing, it cannot maintain its viscosity for a long time, which reduces the efficiency of the surface mount process; and it is easy to collapse, easy to splash, corrosive and produce irritating odor during brazing, which affects the health of users and the environment.
In the process of welding, there are shortcomings such as not full and bright solder joints, obvious residues after welding and darker residues, and organic solvents must be used to clean them.

Method used

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Embodiment Construction

[0008] The lead-free solder paste of the present invention comprises tin base alloy solder powder and tin oil, and the component of this tin base alloy solder powder is tin, silver and copper, and wherein composition (weight ratio) is: tin (Sn) is 91-99%, Copper (Cu) is 0.5-3%, and silver (Ag) is 0.5-6%. Tin oil is a uniform mixture of vegetable oil and lipid compounds of organic polyols, solvents and surfactants, which consists of 0.5-2.0% organic acid, 25-40% mixed alcohol ether, 50-70% natural Rosin, 5-15% natural vegetable oil thixotropic agent and additives, the additives are 0.3-8% release agent, 0.01-1.5% antioxidant, 0.01-4% polymerization inhibitor, 0.2-3.0% auxiliary Composed of flux and 0.3-1.8% wetting agent. The function of the mixed alcohol ether is as a solvent and to adjust the dry humidity of the product, and the ratio of the mixed alcohol ether can be adjusted according to the user's requirements within the above weight ratio range. The role of the natural ...

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Abstract

The invention provides a lead-free solder paste comprising the tin base alloy welding powder and the pewter. The components of the tin base alloy welding powder are as follows (in % by weight): Sn 91-99, Cu 0.5-3, Ag 0.5-6; the components of the pewter are as follows (in % by weight): mixed alcohol ether 25-40, natural colophony 50-70, natural vegetable oil thixotropic agent 5-15, organic acid 0.5-2.0, additives. The lead-free solder paste preparing process includes the following steps: mixing the components of the pewter in proportion, standing to room temperature, putting the pewter in a refrigerating chamber with the temperature of 1 C. to 10 C. for 48 hours; mixing the pewter and the tin base alloy welding powder in the ratio of 1 to 9 in the vacuum dispersion machine, putting the mixture in the package bottle and storing hermetically with the temperature of between 5 C. and 10 C.. The lead-free solder paste is characterized by good surface activity, moderated viscosity, and no smell.

Description

【Technical field】 [0001] The invention relates to a solder paste, in particular to a lead-free solder paste used in the soldering of electronic products and a preparation method thereof. 【Background technique】 [0002] With the development of the electronics industry, the electronic assembly is becoming more and more complex and sophisticated, and the types of solder paste are also increasing. The selection of suitable solder paste is a scientific and systematic project. The solder paste selected by engineers should not only meet the needs of production, At the same time, we should also pay attention to the occurrence of side effects and avoid adverse consequences. [0003] The existing lead-free solder paste is generally used for soldering electronic products. It is composed of solder powder and flux. It has no moderate viscosity, no good diffusivity and bonding, and the adhesion and printability are not very ideal. , After printing, it cannot maintain its viscosity for a ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K35/26B23K35/363B23K35/40
Inventor 倪潮春
Owner 倪潮春
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