The decomposition temperature of flame retardant for extruded board is measured under laboratory conditions and constant temperature rise, so the numerical value indicates the stability and actual decomposition temperature in the production process. In addition, due to the influence of impurities on decomposition and residence time, the decomposition temperature of the selected flame retardant should be at least 20 ℃ higher than the maximum processing temperature of the equipment.
Hexabromocyclododecane is the most effective flame retardant, but ordinary hexabromocyclododecane is easy to decompose. According to the experience of Extrusion board manufacturers at home and abroad, heat stable hexabromocyclododecane must be used for Extrusion board. The decomposition of flame retardant will release highly corrosive hydrogen bromide gas, which will severely corrode the equipment, so that the flame retardancy of Extrusion board will gradually decline with the volatilization of hydrogen bromide, but the decomposition temperature is not higher and better, which should match with the burning point of the board. Generally, domestic equipment is used The decomposition temperature of flame retardant is 240 ℃.
The flame retardant of masterbatch extruded board is made of flame retardant, plastic carrier and dispersant, which are heated by extruder. The composition of flame retardant will account for 40% - 50%. The masterbatch has good dispersibility and no dust. However, its disadvantage is high cost. After one-time hot processing, the flame retardant will inevitably lose a certain amount. If the flame retardant in masterbatch is ordinary type VI, which is not resistant to temperature Bromocyclododecane also has the problems of decomposition failure and equipment corrosion.
Powder flame retardant has the earliest use time and the most extensive application. Its advantages are good economy and flame retardant effect. Its disadvantages are different from the proportion of plastic particles and easy to layer. When using powder flame retardant, attention should be paid to the selection of mixing equipment to avoid settlement layer. In addition, the flame retardant with good stability must be selected, and the hexabromocyclododecane produced in China can only be used directly after resin surface coating treatment.