| 摘要 |
<p>Liquid ink eradicator compsn. contains alkali metal and/or ammonium pyrosulphite, sulphite and/or bisulphite, pref. Na (bi)sulphite, the concn. of these sulphite cpds. being 1 (pref. 0.1-0.4)g per 100 ml water. The liquid pref. also contains a water-soluble carbonate and/or bicarbonate and/or aq. ammonia. It is possible to write over corrections made with this liquid with the same ink. The addn. of carbonate and/or ammonia or alkali metal hydroxide to pH 8-12.5 improved the stability. A typical liq. consisted of 100 ml water, 0.1g Na bisulphite and 0.25g K carbonate.</p> |
