With the continuous advancement of reform and the development of science and technology, China has gone from a backward producer of PCB to an advanced country in the world. In 2003, China's total output value of PCB ranked the second in the world, and the development of PCB industry quickly led the development of surrounding industries and related industries.Now, the advanced and advanced equipment, instruments, instruments and materials used in PCB have made great progress, and they have also turned from a big import country into a big export country. The technical indicators of some equipment and materials have also reached international standards, especially the PCB screen printing ink has reached the highest level in the world.
1. Historical review and application status
China's first printed board came out in 1959 and was only used for mass production in the early 1960s.Initially used as a mask for the production of printed plate graphics is dichromate as a photoreceptor colloids.
1. Three development stages of photosensitive mask
Formaldehyde photoresist: the oldest technology was introduced in the former Soviet union and was quickly phased out due to the complexity of ethanol development.
Braille mask: this technique was adapted from plate-making and label making processes and is economical to use.Later, technicians developed physical and chemical cementing techniques, which were quickly popularized, but could not be stored for long at high temperatures.
This kind of mask can be used for more than one month after it is finished.
None of the above three masks can meet the growing market demand. In view of the fact that most of the lines of printed board graphics were above 1.5mm at that time, a new process method is urgently needed to replace them.
2. Self-made screen printing resist ink
At that time, the screen is silk screen, and network specifications are less, platemaking methods more use "red film" and "etching graphics paint reversal" methods.At that time, self - screen printing anti - corrosion ink formula about the following two:
Petroleum pitch: 200 ~ 300g
Talc powder 50 ~ 200g
Drying oil 10 ~ 15ml
Add the solvent gasoline to 1000ml
Bottom drying type:
150-200g thick paint
Talc powder 20 ~ 50g
Color material: 0.5-1g
20 to 30g rosin
Add turpentine to 1000ml
Conditions: 130 ℃, 30 min
Although the self - made screen printing corrosion resistant ink has many shortcomings, but it is also a leap of PCB manufacturing graphics.
3. Commercialization of screen printing corrosion resistant ink
Seeing the strong business opportunities of China's PCB ink market, ink makers soon launched a variety of models, different performance screen printing corrosion resistant ink, forming the printing plate ink market.Hong Kong, Japan, the United States with the fastest speed will be the company of the PCB screen printing the ink into our country, and to establish a joint venture company, the brand ink, stable performance, easy to use, the most outstanding characteristic is in faded ink had greatly improved in the process, to adopt the method of alkali soluble ink, eliminating the pollution caused by solvent cleaning and solvent.With the increase of TV board and tape recorder board, UV - solidified screen printing ink, obviously speed up the production of PCB board.This ink solid content of 100% solvent free volatilization, circuit board graphics processing is the first choice material, soon in 1-2 years to spread to the country, once a short supply situation, ink manufacturers created unlimited business opportunities.
Light imaging resist resist plating ink
With the enlargement of the PCB material market, one for the graphics electroplating method (also known as the plating method) the corrosion resistance of plating ink is also introduced to our country, the most outstanding advantage is: can not only as a general erosion resistance of the inks (acid etching and alkaline etching) under certain condition, can also be Cu plating, plating PbSn, Sn plating, plating NiAu, and resolution of 0.05 mm / 0.05 mm/line width, line spacing), created the conditions for the machining of the precision of circuit board.
It has become one of the main materials for making graphics, because it does not require special equipment, widely used in the PCB industry, the industry has become the largest amount of ink.