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Tin stripping additive and application thereof

a technology of additives and tin strips, applied in the field of additives for tin stripping, can solve the problems of low purity of metal obtained through this method, air pollution, etc., and achieve the effects of reducing the amount of nitric acid used, preserving the tin stripping efficiency in a desired level, and being friendly to the environmen

Inactive Publication Date: 2015-12-31
UWIN NANOTECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a new tin stripping additive and a tin stripping solution that work well in removing tin without using too much nitric acid. This makes the process safer and less harmful to the environment. Additionally, the invention provides a method for recycling tin from waste electronic components in high efficiency and a reaction tank that facilitates the metal recycling process. This method is easy to operate and friendly to the environment.

Problems solved by technology

However, the burning method may cause air pollution because of the bromine-containing waste gas and dioxin resulted from the burning of the PCBs.
The purity of the metal obtained through this method is too low to be ideal.

Method used

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  • Tin stripping additive and application thereof
  • Tin stripping additive and application thereof
  • Tin stripping additive and application thereof

Examples

Experimental program
Comparison scheme
Effect test

example 1

Test 1 for the Tin Stripping Efficiency of the Present Tin Stripping Solution

[0070]First of all, the tin stripping additive of the present invention was prepared. A copper corrosion inhibitor and a nickel corrosion inhibitor was mixed in a solvent in accordance with the following table 1 to obtain the present tin stripping additives of this example.

TABLE 1Samples of the present tin stripping additives.Copper corrosionNickel corrosioninhibitorinhibitorSolventSamplekindswt %kindswt %kindswt %APotassium5Sodium10water85phosphateoxalateBPotassium10Ammonium5water85dihydrogenchloridephosphateCTrisodium5Potassium5water90phosphatecarbonate

[0071]The following experiments were conducted by using the sample B in the above Table 1. In this example, the efficiency of the tin stripping solution having the present Tin stripping additive in tin stripping was examined. Samples 1 and 2 of the tin stripping solution of this example was prepared in accordance with the following. Table 2 and were applied...

experiment 1

[0072]A motherboard was immersed into said sample 1 at 20° C. for 30 minutes. Please see FIG. 3A and FIG. 3B. FIG. 3A showed a picture took before tin stripping treatment and FIG. 3B showed a picture took after. According to the figures, the tin stripping solution of the sample 1 successfully stripped the tin of the motherboard in 30 minutes.

experiment 2

[0073]A motherboard was immersed into said sample 2 at 25° C. for 20 minutes. Please see FIGS. 4A, 4B, 4C, and 4D. FIGS. 4A and 4B respectively showed a picture took before tin stripping treatment and FIGS. 4C and 4D respectively showed a picture took after. According to the figures, the tin stripping solution of the sample 2 successfully stripped the tin of the motherboard in 20 minutes. Moreover, it was noted from the figures that the copper layer on the motherboard, the nickel layer on the connector, and the legs of the fillet weld of the IC elements were not stripped by the tin stripping solution. It indicated that under proper treatment period, the present tin stripping solution exhibited specificity in stripping tin and would not strip other metals on the object to be processed. In other words, the tin can be recycled in better purity in the tin-recycling procedures thereafter.

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Abstract

The present invention provides an additive for tin stripping, comprising 0.1 to 20 wt % of copper corrosion inhibitor and 0.1 to 20 wt % of nickel corrosion inhibitor; wherein said weight percentage is based on the total weight of said additive. The present additive can be used with nitric acid conventionally used for metal-stripping for not only reducing the usage of nitric acid but also improving the efficiency of tin stripping. The present invention also provides a method for Tin recycle and a reaction tank for metal recycle. Both of them are favorable for satisfying the needs of metal recycle (especially, tin recycle) in the field.

Description

BACKGROUND[0001]1. Technical Field[0002]The present disclosure relates to an additive for metal-stripping; especially for Tin-stripping.[0003]2. Description of Related Art[0004]From ancient times, minerals are closely linked with the development of human society and science. Nowadays, their importance is even more in the electronic industry of modern technology. Various elements of electronic industry, such as a central processing unit, a printed circuit board, a memory, a flip chip, or even a concealed antenna equipped inside the outer shell of a mobile phone, contain metal-plated parts. In fact, those metal-plated parts play important roles in the device. However, minerals resources are not unlimited; therefore, under the sustainable development consideration, how to recycle the metal materials from those metal-plated parts has become a critical task in the industry.[0005]Conventional recycle manners for printed circuit boards (PCBs) in the field include burning method, acid-washi...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C22B25/06C23F1/44C23F11/04C22B3/00
CPCY02P10/228C22B25/06C22B25/04C23F1/44C23F1/30C23F1/46Y02P10/20
Inventor HSU, CHING-HSIANG
Owner UWIN NANOTECH