COMPARISON OF THE PERFORMANCE OF DESICCANTCOATED PAPERS OR BARRIERS AND BAGGED DESICCANT,

Several groups of specimens were exposed to high humidity to evaluate the use and performance characteristics of desiccant-coated papers and barriers as compared to bagged desiccant. The capacity of the bagged desiccant was substantially greater than the desiccant-coated paper due to the larger size of silica gel crystals, but the rate of adsorption was initially greater for the coated paper. When pouches were prepared of a barrier coated with desiccant or containing bag desiccant, the ability of the desiccant systems to adsorb water was far in excess of the transmission rate of the barrier, and therefore the adsorption rates represent the permeability of the individual barrier or test specimen. The binder of desiccant-coated papers and barriers appeared to reduce the tendency to produce fine loose particles referred to as dusting, but this advantage was partially offset by other factors such as limited loading of desicant, lack of heat sealability, and the exclusion of barriers that soften or melt below 250 F the reactivation temperature of the desiccant. Author