| 摘要 |
<p>PURPOSE: To bleach a fibrous paper stock by using a specific amount of formamidine sulfinic acid as a bleach to increase a whiteness value even on using a high substrate concentration in bleaching the fibrous paper stock by using a high temperature and a high substrate concentration together with a mechanical treatment. CONSTITUTION: This method for bleaching a fibrous paper stock such as waste papers comprises adding formamidine sulfinic acid as a bleaching agent in a ratio of 0.05-2.5 wt.%, preferably 0.2-1.2 wt.% based on the bone dry total fibrous material together with preferably an alkalizing compound such as sodium hydroxide in simultaneously performing a mechanical treatment or a heat/ mechanical treatment to bleach for increasing a whiteness value even in use at a high temperature of approximately 120 deg.C and in a high substrate concentration of 25-30 wt.% for the mechanical treatment or the heat/mechanical treatment.</p> |
