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Review and analyze the development of silk screen printing inks in China

feel the development of silk screen printing inks in China from the historical review of PCB ink sales war

with the continuous promotion of reform and the development of science and technology, China has leapt from a backward PCB producing country to an advanced country in the world. In 2003, the total output value of PCB in China ranked second in the world, and the development of PCB industry soon led to the development of surrounding industries and related industries. Now, no matter the high-end cutting-edge equipment, instruments, meters and materials used for PCB have developed by leaps and bounds, and they have also changed from a large importer to an exporter. The technical indicators of some equipment and materials have also reached international standards, especially the PCB ink has reached the world's highest

I. historical review and application status

the first printed board in China came out in 1959 and was only used for mass production in the early 1960s. Initially, the mask used to make printed board graphics was a colloid with heavy chromium and sodium bicarbonate as photosensitizers

1. Three development stages of photosensitive mask

① shellac photosensitive mask: this oldest technology was introduced from the former Soviet Union and was soon eliminated due to the complexity of ethanol development process

② bone glue photosensitive mask: this technology is transplanted from the plate making and label making process, which is economical and practical. Later, the technicians further developed physics. After that, the Ministry of public security put forward the opinion that the solid film and chemical solid film technology were greater than or equal to 30, which was soon popularized, but they could not be stored for a long time at high temperature

③ polyvinyl alcohol photosensitive mask: this kind of mask can be used for more than a month after being prepared, and its physical and chemical properties are stable, which is much better than bone glue mask

none of the above three masks can meet the growing market demand. Since the lines of printed board graphics were mostly more than 1.5mm at that time, a new process method is urgently needed to replace it

2. Self made anti-corrosion ink

at that time, all the silk used was silk, and the mesh size was small. The plate making method mostly used the red film etching and the painting inversion method of etching graphics. At that time, there were about two formulations of self-made anti-corrosive ink:

① self drying type:

petroleum asphalt 200 ~ 300g

talc powder 50 ~ 200g

dry oil 10 ~ 15ml

solvent gasoline to 1000ml

② drying type:

thick paint 150 ~ 200g

talc powder 20 ~ 50g

pigment 0.5 ~ 1g

rosin 20 ~ 30g

Add turpentine to 1000ml

condition: 130 ℃, 30min

although the self-made anti-corrosion ink has many shortcomings, it is also a leap in PCB manufacturing graphics in China

3. Commercialization of anti-corrosive printing inks

ink dealers saw the strong business opportunities in China's PCB ink market, and soon launched a variety of types of anti-corrosive printing inks with different performance, forming the ink market for printed boards. Hong Kong, Japan and the United States have also introduced the company's PCB Printing anti-corrosion inks to China at the fastest speed, and established joint ventures. These brand inks have stable performance and easy to use. The most prominent feature is that they have been greatly improved in the process of ink fading. The method of alkaline solution is used to remove the ink, eliminating the pollution caused by solvent cleaning and solvents. With the increase of TV boards and recorder boards, UV curing anti-corrosion silk screen printing ink came out, which significantly accelerated the production speed of PCB boards. The solid content of this kind of ink is 100% solvent-free volatilization. It is the preferred material in the graphic processing of circuit boards. It was soon promoted to the whole country within 1 to 2 years. There was a situation that the supply exceeded the demand for a time, creating unlimited business opportunities for ink manufacturers

4. Photo imaging anti-corrosion and anti Plating Ink

with the expansion of the PCB material market, a kind of anti-corrosion and anti Plating Ink for graphic electroplating (also known as reverse plating) has also been introduced into China. The most prominent advantage is that it can not only be used as a general anti-corrosion ink (acid resistant etching and alkaline etching under certain conditions), but also be resistant to Cu, PbSn, Sn and NIAU, and the resolution can reach 0.05mm/0.05mm (line spacing/line width), It creates conditions for the processing of precision circuit boards

it has become one of the main materials for manufacturing graphics. Because it does not need special equipment, it is widely used in large, medium and small enterprises in the PCB industry. Now it has become the most used ink in the PCB industry

II. Solder resist ink

solder resist ink should be permanently left on the surface of the printed board to protect the circuit and play an insulating role. It can also protect the circuit when blowing Sn (coating the bonding pad and hole wall with SN), and only weld with the welding pad of cutting components when the wave peak

1. Development of solder resist inks

solder resist inks coated on the surface of printed boards originated in the late 1960s, while China's solder resist inks for printed boards began in the late 1970s and began to transfer from imports to domestic production. At the same time, thermosetting character inks also appeared. Later, due to the heat-resistant conditions of the printed boards of televisions, recorders and cameras, UV curing solder resist inks were also introduced one after another. After a few years, the varieties have also increased: in addition to different colors, there are also bright types, matte types, cloth patterns, wrinkles, etc. for users to choose

2. Photo imaging solder resist ink

whether it is thermosetting solder resist ink or UV solder resist ink, its coating method is to print graphics to expose the pad of the printed board. However, as the line spacing between printed board graphics and bonding pads gradually becomes smaller and denser, the method of printing graphics with pumps has been unable to meet the requirements. Although the method of resistance welding dry film has been popular for several years, due to its expensive materials, the manufacturing technology of special vacuum film applicator is not popular, the operation process is complex, and the yield is low. Now this technology has been eliminated. Nowadays, the photo imaging solder resist ink is suitable for high-density printed boards. In addition to its thermosetting and UV solder resist properties, the most prominent is its resolution advantage (basically equivalent to photo imaging anti-corrosion and anti electroplating ink)

3. Application and popularization of photo imaging solder resist inks

although there are also applications of thermosetting solder resist inks and UV curing inks in the scope of solder resist inks, these can only be used on one side. Its structural parts are made of duranthan Akv 50 h2.0 nylon 66 of LANXESS and low-grade electronic product printing boards. Photo imaging solder resist inks are also needed in the production of medium and high-grade printed boards. With the development of curtain coating technology and the general increase of line density of printed boards, photo imaging solder resist inks have been widely used in large, medium and small enterprises

from the perspective of PCB ink market, photo imaging anti-corrosion and anti electroplating ink and photo imaging solder resist ink are not only the main products of PCB ink, but also the main materials in the production of high-precision PCB

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