| 摘要 |
<p>Correction system for use on tracing paper marked with India ink or other types of ink comprises (1) a solvent applied first to dissolve the ink, and (2) a porous material to absorb the dissolved ink. The solvent contains at least one of an alcohol, a ketone, an aldehyde, a weak acid and a weak base, plus sufficient of a strong acid to give pH 0-2 (0-1). Component (2) is pref. cotton wool, gauze, blotting paper, artificial or natural leather in the form of a pad, powder or tissue. Opt. the system also includes a second liq. consisting of alcohol, ammonia, liq. soap and NaOH to give pH 12-14. This liq. eliminates any curling of the paper caused by the solvent. The solvent depolymerises already dried ink, converting it back to liq. The system is easy to apply and (unlike conventional erasers) does not damage the paper.</p> |
