METHOD FOR MANUFACTURING DRY GEL, AND HEAT INSULATING MATERIAL PRODUCED BY THE METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for making water-repellent a gel which does not shrink when dried and hardly absorbs water over a long time while the equipment cost is restrained from being raised for enhancing the corrosion resistance. SOLUTION: A wet gel is prepared in a stainless steel-made gelating vessel by using tetramethoxylane as a raw material and a sol-gel method. The solvent in the wet gel is replaced with hexane and then the gel is separated from hexane by filtration. The separated gel is injected into a Teflon (R)-lined stainless steel-made drying vessel, made water-repellent by filling it with trimethylchlorosilane-saturated vapor at 80 deg.C and then dried by circulating nitrogen heated to 150 deg.C for one hour. The obtained gel shows the density and thermal conductivity equal to those of the gel obtained by the conventional method. The equipment cost can be restrained from being raised by making only the drying vessel acid-resistant.