Low-acidity etching production method for PCB and double-liquid type acidic etching liquid system

Abstract

The invention belongs to the technical field of acid etching, and particularly relates to a low-acidity etching production method for a PCB (printed circuit board) and a double-liquid type acid etching liquid system. An acid-reducing auxiliary agent of an acid etching liquid adopted in etching production comprises one or two of cyanate and oxalic acid dihydrazide; and the cyanate comprises sodium cyanate, potassium cyanate or ammonium cyanate. The cyanate and the oxalic acid dihydrazide are used as the etching liquid deacidification auxiliary agent, and an additive is formed by the auxiliary agent and is applied to the PCB acid etching liquid, so that the etching rate can be increased, and the etching factor can be increased; and after the acid etching liquid for PCB production is mixed with the etching liquid additive, the concentration of the adopted oxidant is reduced, and the acid equivalent of the whole system is reduced. The used etching liquid additive can replace 31% industrial concentrated hydrochloric acid adopted traditionally, the etching rate reaches 40-50 microns/min, the etching factor reaches 4.0-5.0, and the additive is greatly superior to a traditional double-solution type acid etching solution.

Description

technical field [0001] The invention belongs to the technical field of acid etching, and in particular relates to a low-acidity etching production method for PCB boards and a two-liquid acid etching solution system. Background technique [0002] With the update and iteration of electronic products and increasingly powerful functions, the requirements for various accessories of combined electronic products are also rising, especially the PCB, known as the "mother of electronic products", has constant requirements for its precision and conductivity. promote. Therefore, PCB manufacturing companies are also constantly improving their comprehensive process capabilities. At present, more than 50% of the world's PCB manufacturing capacity is in China. Chinese PCB manufacturing companies not only have to face the improvement of technology and manufacturing capabilities, but also face labor costs. A series of problems such as rising and increasing pressure on environmental protectio...

AI Technical Summary

Problems solved by technology

For example, in acid etching production, the higher the acid equivalent, the faster the etching rate will be. When the acid equivalent in the acid etching production tank exceeds 2.5, the following negative effects will be brought: first, the acidity in the acid etching production tank exceeds 2.5 equivalent When the acidity exceeds 2.5 equivalents, the production tank is prone to the following side reactions: 6H++ 5Cl-+ClO3-→2Cl2↑+3H2O, The chlorine gas produced by this reaction is a highly toxic gas, which can cause serious safety accidents; third, when the acid equivalent of the acid etching production tank exceeds 2.5, a large amount of hydrogen chloride in the production tank will volatilize due to the long-term maintenance of the production tank above 50 °C into the air

Most of them are absorbed by the tail gas absorption system, resulting in an increase in the amount of caustic soda used in the tail gas absorption system. At the same time, the requirements for the absorption capacity per unit time of the tail gas absorption system are increased, which increases operating costs and equipment investment.

A small amount of hydrogen chloride spills into the air of the workshop, which will affect the health of production employees, and seriously cause occupational diseases of the respiratory tract; fourth, when the acid equivalent of the acid etching production tank is above 2.5, the acidity of the washing water will increase accordingly , the wastewater station needs to add more caustic soda to neutralize, increasing the cost of wastewater treatment

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