Recent concerns over use of brominated flame retardants (BFRs) have increased interest in halogen-free electronics. However, BFRs are not the only source of halogens in PCBs. Most PCB resins are epoxies and epoxy resins contain measurable levels of chlorine. Additional halogens are added to PCB laminates through glass sizes, wetting agents, curing agents and resin accelerators. It is important to realize that even without use of BFRs, there may be finite levels of halogens present as impurities in your product.
halogen-free PCBs are becoming more and more popular because they are constructed of materials that are free of halogen. The dielectric constant, dissipation factor and moisture diffusivity of materials that are described as halogen-free are different from those employed in traditional printed circuit boards.
|Halogen-Free PCB||Meterial||TG(DSC,℃ )||TD(WT, ℃)||CTE-z(ppm/℃)||Td 260(min)||Td 288(min)|