Flexible elastomeric foams
Flexible elastomeric foams (FEF’s) are widely used for thermal and acoustic insulation in air-conditioning and heating installations. Such materials are more or less solely based upon two different rubbers:
- nitrile butadiene rubber (NBR), often blended with polyvinyl chloride (PVC)
- or ethylene propylene diene rubber (EPDM).
NBR and NBR/PVC based FEF’s are the most widespread polymers for standard FEF’s. EPDM is mainly used for applications requiring higher temperature resistance, e.g. solar applications.
PVC resins are blended with NBR to provide increased resistance to ozone and abrasion. PVC also has the effect of increasing the level of fire retardancy, and this can be further improved by the addition of flame retardant fillers.
Selecting the correct Flame Retardant(FR) filler
It is very important that the flame retardant fillers are sufficiently fine enough to maintain a good foam structure. At the same time, the filler should have a relatively high surface area per gram because this benefits the bubble structure inside the foam.
LKAB Minerals' UltraCarb LH15 C and UltraCarb 1251 meet these criteria perfectly.