| 摘要 |
<p>PURPOSE:An ink composition erasable with an alkali, heat, etc., having stable recording properties during reprinting, obtained by blending basic dye such as azo type, etc. as a main agent of ink with thiourea dioxide. CONSTITUTION:One or more dyes of azo type, methine type and triphenyl type basic dye are used as a main agent of ink, it and thiourea dioxide are dissolved in an aqueous solvent such as water, etc., to give the desired ink composition. In erasing with heat, mistaken record is traced with a hot brush pen so that thiourea dioxide is decomposed, and a sulfinic acid is liberated. In erasing with an alkali, mistaken record is traced with an alkali aqueous solution, so that thiourea dioxide is neutralized and it is erased.</p> |
