荧光增白剂对杨木BCTMP浆光致返黄的抑制作用

Application of Fluorescent Whitening Agents against Light-induced Colour Reversion of Aspen BCTMP

采用荧光增白剂(FWA)作为杨木BCTMP浆的光学稳定剂,通过浆内添加或手抄片表面涂饰来系统探讨FWA提高杨木BCTMP浆光学稳定性的作用效果。结果表明,2S和4S型FWA在浆内添加时抑制BCTMP浆返黄的效果较好,而4S和6S型在手抄片表面涂饰时效果较好。浆内添加时FWA的用量较高,浆料pH值为中性或弱碱性,需要一定的混合时间;而在手抄片表面涂饰时FWA在较低用量下便可以大大改善杨木BCTMP浆的光学稳定性。

In recent years, hardwood high yield pulp （HYP） with its unique properties has increased applications in many value-added paper grades. However, one of the main drawbacks to limit its wider use is related to the optical properties of HYP, which is the photo yellowing due to its high lignin contents. In this paper, the fluorescent whitening agents （FWA） were used as inhibitors, and their effectiveness were determined through adding in wet-end and coating on the surface of HYP handsheets. The results showed that good inhibiting effect can be obtained when 2S-or 4S- type FWA is used in papennaking wet end; while for surface application 4S- or 6S-type FWA is better. The dosage of FWA is relatively high; also the neutral or weak alkaline pH and a certain mixing time are needed when it is applied in the furnish. While for surface application, the brightness stability of HYP can be improved a lot at the relatively low FWA dosage.