Abstract: A rotary fiberization method and apparatus. Gas and/or liquid may be introduced into the void area produced by a rotary fiberization process. The gas and/or liquid may be used to alter the configuration of the fiber column and to apply desired materials to the fibers.

Abstract: This invention relates to pipe insulation useful at relatively high temperatures, e.g., 850.degree. F. Mineral fibers bonded with phenol-formaldehyde resins and conventional anti-punking liquid resin systems have been developed as a means of producing thermal insulation of relatively low density. However, sustained punking of the binders employed caused exothermic reactions whose temperatures fused the low density mineral fibers causing thermal and structural degradation of the insulation. The present invention utilizes a relatively dense layer of fiber glass having a relatively low binder content, bonded with a binder comprising an antipunk phenolic resin and high levels of silane based on the solids content in the resin. An outer layer may surround the dense layer and be constructed with a lower density and a higher binder content.