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 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 [url=https://www.pcbmake.com/what-is-halogen-free-pcb/]Halogen Free PCB[/url], 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.