Patent ID: 7927655

Claim:
A method for preparing a dehumidifying element comprising the steps of: (A) coating super absorbent polymer (SAP) particles having a particle size in the range of from 10 μm to 100 μm onto a surface of a sheet, wherein said SAP is cross-linked and is selected from the group consisting of polyacrylic acid, polyacrylamide, polymethacrylic acid, polyvinyl alcohol, graft polymer of starch, cellulose derivatives, and copolymers of the foregoing; (B) then distributing undissolved inorganic salt particles onto the SAP particles coated on said sheet, wherein said undissolved inorganic salt particles are selected from the group consisting of magnesium halide, calcium halide, zinc halide, lithium halide, aluminum halide, and mixtures thereof; (C) then exposing said coated sheet to a high humidity atmosphere comprising water vapor dispersed in air for a predetermined time, whereby the inorganic salt particles are absorbed into the SAP particles by ion exchange; and (D) then drying the sheet at elevated temperature; wherein the mixing ratio of the SAP particles to the undissolved inorganic salt particles is in the range of from 1:0.1 to 1:5.