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.
(3) polyvinyl alcohol photosensitive mask: this kind of mask with good available after more than a month, physical and chemical performance is stable, has made great progress than bone collagen mask.
The above three types of mask are unable to meet the growing market demand, given the PCB graphic lines are above 1.5 mm, urgent need a new kind of method instead.
2. The homemade screen printing the ink
At that time, the wire mesh is used silk screen, and mesh size is less, plate-making methods more carved "red film" and "etched pattern painting inversion method.At that time from the distribution network to print the ink formula about the following two kinds:
(1) the dry type:
Asphalt 200 ~ 300 g
Talcum powder 50 ~ 200 g
Dry oil 10 ~ 15 ml
Add 1000 ml solvent gasoline
Bottom drying type:
Paste paint 150 ~ 200 g
Talc powder 20 ~ 50g
Pigment 0.5 ~ 1 g
Rosin 20 ~ 30 g
Turpentine oil added to 1000 ml
Conditions: 130 ℃, 30 min
Although the homemade screen printing the ink exist many shortcomings, but it is also a leap of our country's PCB manufacturing graphics.
3. The screen printing the ink of commercialization
Ink developers see a powerful China PCB ink market opportunity, and soon launched a variety of models, the performance of different screen printing resist inks, formed the PCB 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.Along with the increase in the TV board and recorder board, UV screen printing ink type of corrosion, significantly speed up the PCB production speed.This ink solid content 100% without solvent volatilization, is the preferred material in circuit board graphics processing, soon promoted to the whole country, in 1 ~ 2 years once appeared in short supply situation, to ink manufacturers create the unlimited business opportunities.
4. Light imaging corrosion resistant 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.