Rock wool fiber HB21L, an inorganic silicate fiber, is made of basalt, diabase and dolomite by blowing or centrifugation at high temperature. It is grey-green and pure. To promote its dispersion and adhesion, we mix a little liquid phenolic resin. Finally it is yellow-green. After fixing length and shot removal, a mass of fine, intertwined fibres are created.
Since the matrix in the friction material is an organic phenolic resin, and the rock wool fiber is an inorganic reinforcing fiber, there is a problem of poor interfacial bonding between the rock wool fiber and the matrix resin. Therefore, we usually use surfactants to modify the surface of rock wool fibre, which can improve its compatibility with organic binders.Since rock wool and its products are light and fibrous materials and are produced by dry method, a certain amount of dust will be generated during the processing of raw material melting, product cutting and etc. Dust can irritate to the skin. The fiber after surface treatment can inhibit the fine dust in the mixture to reduce the irritation of the dust to the skin and improve the working environment.