Method of producing calcium silicate type high temperature thermal insulation materials (US Patent 3,574,113, 1971)

Richard F. Shannon received US Patent No. 3,574,113 on April 6, 1971, filed April 18, 1968. It was assigned to Owens Corning Fiberglas Corp.

The patent's abstract:

AN IMPROVED METHOD OF FORMING HIGH STRENGTH HIGH TEMPERATURE INSULATION MATERIALS WHEREIN AN UNDISRUPTED TOBERMORITE GEL NETWORK HAVING THE FORMULA 3CAO$2SIO2$3H2O IS FIRST FORMED BETWEEN DISPERSED FIBERS IN A SLURRY AND THIS NETWORK IS THEREAFTER TRANSFORMED IN AN AUTOCLAVING PROCESS TO CALCIUM SILICATE CRYSTALS HAVING A CALCIA TO SILICA RATIO OF LESS THAN APPROXIMATELY ONE. THE CONVERSION OF THE TOBERMORITE GEL TO CRYSTALS IS ACCOMPLISHED BY THE DIFFUSION OF SILICA INTO THE GEL NETWORK. FREE LIME AND SILICA ARE DISTRIBUTED THROUGHOUT THE GEL, AND DURING AUTOCLAVING, THE SILICA IS DISSOLVED BY THE FREE LIME AND MADE AVAILABLE FOR DIFFUSION INTO THE CRYSTALLINE LATTICE OF THE TOBERMORITE GEL. THE TOBERMORITE GEL NETWORK IS SET TO THE FIBERS BY THE HEATING OF CALCIUM SILICATE SLURRIES CONSISTING OF EITHER DICALCIUM SILICATE, OR TRICALCIUM SILICATE, OR BOTH IN AN ABUNDANCE OF WATER AT TEMPERATURES BETWEEN 160F. AND 212C. THE FORMATION OF THE GEL BETWEEN THE FIBERS MUST BE COMPLETE AND MUST NOT BE DISRUPTED, OR DRIED, PRIOR TO THE AUTOCLAVING PROCESS.

Where it was listed

• Barry Castleman, Asbestos: Medical and Legal Aspects (5th edition, 2005)