抄録
A large amount of eggshells are discarded by the food industry, and their disposal by incineration or landfill involves considerable costs. In order to utilize this bioresource efficiently, the use of eggshell calcium carbonate (ECC) as a coating pigment for ink-jet paper was investigated. ECC was found to have high adsorption ratio for magenta dye, which suggests that it can be a complementary pigment for silica that has widespread commercial use. A trial ink-jet paper prepared from ECC particles less than 1μm in diameter exhibited a higher color density than those prepared from particles with a diameter of 5μm. The higher color density is presumably because of slow ink penetration into the paper and higher lateral spread on the paper surface, which result from the packed structure associated with the broad particle size distribution and high dispersibility of the EEC particles. Further, in the printing test, ECC particles less than 1μm in diameter led to severe bleeding, as implying the same mechanism as for the higher color density. However, the ECC-coated surface exhibited higher hydrophilicity than those coated with precipitated calcium carbonate (PCC); the higher hydrophilicity is a result of a lower contact angle with water. Consequently, the formation of microaggregates of ECC particles would be expected to enhance the color density and lead to low bleeding.
