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Looking at the development of silk screen printing inks in China from the perspective of PCB ink sales War (I)

with the continuous promotion of reform and the development of science and technology, China has leapt from a backward PC B producing country to an advanced country in the world. In 2003, China's total output value of PCB ranked second in the world. The development of PCB industry has quickly driven the development of surrounding industries and related industries. China automotive materials made an exclusive interview with Mr. wangqingguo, director of the non-metallic branch of the society of Automotive Engineers of China and vice minister of 1 automotive materials department. Now, both high-end cutting-edge equipment, instruments, meters and materials for PCB have developed by leaps and bounds, and they have also changed from an import country to an export country. The technical indicators of some equipment and materials have also reached international standards, especially the PCB printing ink has reached the highest in the world

I. historical review and application status quo

the first printed board in China came out in 1959 and was only used for mass production in the early 1960s. The original mask used to make printed board graphics was a colloid with dichromate as photosensitive agent

1. Three development stages of photosensitive mask ① shellac photosensitive mask: this oldest technology was introduced into the national standard of spring testing machine by 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 plate making and label making process, which is economical and practical. Later, technicians developed physical and chemical solid film technologies, which were quickly popularized, but 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 one 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 most of the lines of printed board graphics were more than 1.5mm at that time, a new process method is urgently needed to replace them

2. Self made anti-corrosion ink

at that time, all the silk used was silk, and the mesh size was small. The plate making methods mostly used the methods of "etching red film" and "etching pattern painting reversal". At that time, there were about two self-made anti-corrosion ink formulations:

① self drying type:

petroleum asphalt 200 ~ 300g

talc powder 50 ~ 200g

dry oil 10 ~ 15ml

solvent gasoline added to 1000ml

② drying type:

thick paint 150 ~ 200g

talc powder 20 ~ 50g

pigment 0.5 reduced aircraft weight ~ 1g

rosin 20 ~ 30g g

add turpentine to 1000ml

condition: 130 ℃, 30min

although the self-made anti-corrosion printing 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 a strong business opportunity 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 are 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 popularized 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 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 resistance and alkaline resistance 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 (the bonding pad can not be separated from the substrate and the hole wall is coated with SN), and it can only be welded with the welding pad of the cutting components at the wave peak

1. The development of solder resist inks the solder resist inks on the surface of printed boards originated in the late 1960s, while the solder resist inks of printed boards in China began to transfer from imports to domestic products in the late 1970s. At the same time, thermosetting character inks also appeared. Later, due to the heat-resistant conditions of the printed boards of TV sets, tape recorders and video 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 type, matte type, cloth pattern type, wrinkle type, 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 solder pad of the printed board. However, as the line line spacing between printed board graphics and solder pad becomes smaller and denser, the method of printing graphics with pump can not 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 outstanding thing is its resolution advantage (basically equivalent to the photo imaging anti-corrosion and anti electroplating ink)

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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