Squarylium Dyes Useful for Electrochemical Printing
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-11
As electrochemically active leuco dyes for printing, a promising class of compounds, of which I (R=R'=p-C(6)H(4)OCH(3)) is a member, has been identified. Leuco dye I has been coated on paper, and shows no propensity for ambient oxidation and no background color develops. When the paper is treated with an oxidant such as bromine, a brightly colored dye II is obtained which fades little, if at all. High quality print has been obtained using this leuco dye along or in combination with other leuco dye(s).