For the inner insulation of collars Hiltex works with Superwool HT
The Superwool blanket is a product with a chemical composition of 75% SiO2 and 25% CaO/MgO. The insulation blanket contains no aluminium oxide and retains excellent thermal insulation performance at temperatures up to 1200ºC (2192ºF).
Quartz and ALF collars and discs products are considered to be environmentally friendly "green" products. Quartz products are NOT silicate but silica fibers. Due to the fiber diameter and length, quartz is considered non-respirable. The product form is amorphous and is classified in group 3 according to the IARC Monograph; it is therefore NOT classified as dangerous.
Quartz products are not listed under de EC Directive 97/69EC of December 5, 1997. ALF products are produced from continuous fiber with a diameter of 7 microns. Because of the diameter and length of the fibers, ALF products are considered non-respirable as defined
under the WHO Convention (IARC), and the fibers are outside the diameter range considered respirable under NIOSH standards and European Directive 97/69/EC.