ロイコ染料における発色と帯電特性

Abstract

The color development and tribo-charging characteristics of the leuco dyes were investigated. Seven types of leuco dyes were dissolved into a styrene-acryl copolymer solution to prepare a dye-solution. When a prescribed amount of the t-butyl salicylate-Zn complex (SZC) was added to the dye-solution the solution developed color. The maximum absorbance A m a x of the solution increased linearly with the increasing amount of SZC added to the dye-solution. The dye-SZC-solution was coated on a SUS plate and dried up to fabricate a dye-SZC/resin matrix film. Ferrite beads were cascaded onto the matrix film and the amount of generated charges was measured. It turned out that SZC acted as a positive charge enhancing agent to the matrix film, and the amount of cascade charge shifted toward the positive direction. In most cases, the amount of charge difference ΔQ increased with the increasing amount of SZC added to the solution. It is remarkable that SZC, which has been regarded as a typical negative charge imparting agent or a negative charge control agent (CCA), acted as a positive charge enhancing agent. The above results are explained by an interaction between an electron donating leuco dye molecule and an electron accepting SZC molecule in the resin solution or on the matrix film surface. The amount of A m a x can be used as a measure to estimate the strength of the interaction. It was confirmed that the amount of A m a x is closely related to the amount of charge difference AQ. The difference of the characteristics between A m a x in the solution and AQ on the matrix film surface is also discussed.