Halogen free, halogen free (HF), with the rising awareness of environmental protection, countries began to ban relevant halides one after another. It is required that the halogen (CL, BR) content in the mean value shall be less than 900 ppm respectively and the total shall be less than 1500 ppm.
Halogen group Ⅶ a non-metallic elements, including fluorine-, chlorine, bromine, iodine, astatine and tennessine, are collectively called halogens. Astatine is a radioactive element, and halogens commonly referred to are fluorine, chlorine, bromine and iodine. Halogen compounds are often used as a kind of flame retardant: PBB, PBDE, TBBP-A, PCB, hexabromododecane, tribromophenol, short chain chlorinated paraffin, etc. they are used in electronic components and materials, product shells, plastics, etc. Halogen flame retardants include chlorine flame retardants, bromine flame retardants, polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol-A (TBBP-A), hexabromocyclododecane (HBCD) and others. Chlorinated stone (c10-13, SCCP) chlorinated alicyclic hydrocarbon tetrachlorophthalic anhydride (TCP) other halogen compounds polychlorinated biphenyls (PCBs): emollients, capacitor oil, polychlorinated naphthalene (PCNs): emollients, preservatives, polychlorinated terphenyls (PCTs): emollients, preservatives.
The flame retardant added to SMC sheet is generally aluminum hydroxide. Aluminum hydroxide is non-toxic, halogen-free, and does not produce corrosive products. These are the characteristics of its use. In addition, the reason why it is popular is that it is widely used and plays an important role in many fields. In the Unsaturated Poly (vinyl acetate) cast plastics reinforced by Borui fiber (such as various high-voltage or low-voltage electrical switches), aluminum nitride is used as a filler to make the plastic products have shock resistance, smoke elimination and arc resistance. Aluminum hydroxide is also used in FRP laminates.
