PORTAFLAME® C 75 is produced from carefully selected, naturally occurring hydrated calcium borate. PORTAFLAME® GC 75 is produced from carefully selected, naturally occurring hydrated aluminium and boron containing minerals.
The standardised quality of PORTAFLAME® C 75 and GC 75 is guaranteed by means of an ISO 9001 certified quality management plan. The chemical composition of raw material and product is closely monitored and particle size kept within a narrow variation.

PORTAFLAME® C 75 and GC 75 are characterised as flame retardant (FR) mineral fillers especially developed for the bitumen roofing industry. Flame retardant requirements of EN 13501-5 norm as tested in accordance with the ENV 1187-1, ENV 1187-2 and ENV 1187-4 tests are effectively met if used appropriately. PORTAFLAME® GC 75 was developed as an economically attractive FR for bitumen processed at temperatures below 200 °C. PORTAFLAME® C 75 is thermally stable up to 330 °C and is used as FR in bitumen processed above 200 °C. The flame-retarding action of PORTAFLAME® GC 75 and C 75 is based mainly upon their high char forming and glazing/fluxing ability in combination with endothermic decomposition (heat-sink effect).

Absorption of aromatic oils is comparable to the standard fillers with about the same particle size distribution.