We often see some customer send us PCB RFQ with an additional note "Halogen free required" . So why some of the PCB require no halogen?
First of all let's define what is "halogen-free substrate"
According to JPCA-ES-01-2003: copper clad with Cl and Br less than 0.09% Wt can be called halogen-free. (Cl+Br total <=0.15%[1500PPM])
Typical halogen free substrate includes: TUC883, DE156(ISOLA), GreenSpeed series, S1165/1165M (Shengyi), S0165, etc.
Next topic: why we do not want Halogen
Halogen elements includes: F, Cl, Br, I. Today's flame retardant substrates such as FR4, CEM-3, its retardant factor is brominated epoxy resin.
Researsh shows that retardant material which includes halogen (PBB, PBDE) will emit Dioxin , TCDO and Benzfuran while burning, these emissions will do severe harm to human body that will cause cancer.
The Europe Union established law against these six harmful brothers including PBB and PBDE. While in China the government also forbids any electronics contain lead, mercury, hexavalent chromium and Polybrominated biphenyls.
As we understands that PBB and PBDE has been disappeared in copper clad industry, people now use other replacements such as bromophenic acid. Copper clads with these materials, though not forbided by any country law yet, will emit poisonous gas and high amount of smoke. And in the soldering of components process it will also emit a small amount of hydrogen bromide, whether this is harmful to human body is still under evaluation.
So using materials including halogen elements will have serious side effects.
Halogen free substrate
Currently most halogen free material contains phosphorus or phosphonitryl. These materials can generate partial polyphosphoric acid with strong perperty of dehydration while in buring. A layer of carbonized membrane on polymer resion can isolate the surface and air so to let the fire off.
At chee mau all of our PCB are made halogen free to ensure the human health, you can send inquiry to us anytime.