Hydrated fillers such as ATH achieve their flame retardance by decomposing endothermically, with the release of water close to the temperature at which the polymers themselves decompose. They do not have smoke and corrosive gas problems associated with other types of flame retardants.
For a high-performing HFFR compound with very high ATH loadings of 60 to 65 wt. %, the ATH particle size and shape have to be carefully controlled.
Oligomeric vinyl silanes will release a significantly reduced quantity of alcohol (and hence lower VOC emissions) upon reaction with moisture. Correct use of Dynasylan® oligomeric vinyl silanes may also reduce compound viscosity and produce a smooth, defect-free surface. When vinylsilanes are used in HFFR materials, a small amount of peroxide is required to obtain good coupling.