What is halogen-free PCB board? Halogen free plate refers to copper clad plate with chlorine (C1) and bromine (BR) content less than 0.09% wt (weight ratio) respectively in accordance with jpca-es-01-2003 standard. Meanwhile, the total amount of CI + BR is ≤ 0.15% [1500ppm].To get more news about Halogen Free PCB, you can visit pcbmake official website.
At present, most of the halogen-free plates are mainly composed of phosphorus and phosphorus nitrogen systems. When the phosphorus containing resin is burned, it decomposes by heat to produce metapolyphosphate, which is highly dehydrated, forming a carbonized film on the surface of the polymer resin, separating the burning surface of the resin from the air, and making the fire extinguished to achieve the flame retardant effect. The polymer resin containing phosphorus and nitrogen compounds can produce non combustible gas during combustion, which helps the resin system to be flame retardant.
Characteristics of halogen free sheet
1. Insulation of materials
Because P or n is used to replace the halogen atom, the polarity of the molecular bond segment of epoxy resin is reduced to a certain extent, thus improving the insulation resistance and resistance to penetration of the material.
2. Water absorption of materials
Due to the fact that N and P in n-p-based deoxidizing resin have less electron to halogen, the probability of hydrogen bond between n-and P-based deoxidizing resin and hydrogen atom in water is lower than that of halogen-free material, so the water absorption of halogen-free material is lower than that of conventional halogen-based flame retardant material. For sheet metal, low water absorption has a certain impact on improving the reliability and stability of the material.
3. Thermal stability of materials
The content of nitrogen and phosphorus in Halogen-free plate is higher than that of halogen in common halogen materials, so the molecular weight and TG value of monomer are increased. In the case of heating, the mobility of its molecules will be lower than that of conventional epoxy resin, so the thermal expansion coefficient of halogen-free materials is relatively small.
Compared with halogen-containing plates, halogen-free plates have more advantages, and halogen-free plates replace halogen-containing plates are also the general trend. At present, there are many kinds of halogen-free solder resist ink in the world. Its performance is similar to that of ordinary liquid photosensitive ink, and its specific operation is basically similar to that of ordinary ink.