含酵素－臭氧漂白之無氯漂白及臭氣漂白漿之回色

Enzone Bleaching Sequence and Color Reversion of Ozone-Bleached Pulps

蘇裕昌(Yu-Chang Su) ； 陳鴻財(Horng-Tsai Chen)

《台灣林業科學》 16卷2期 (2001/06) Pp. 93-102

https://doi.org/10.7075/TJFS.200106.0093

摘要

本文以最佳臭氧漂白條件配合酵素進行化學紙漿漂白流程之評估，同時對臭氧漂白紙漿進行回色控制試驗。經氧鹼脫木質素反應後先行以酵素作前處理，再進行不同漂白條件之臭氧漂白，評估漂白性及漂白紙漿白度安定性。此外，臭氧漂白後紙漿分別經熱水抽出、鹼萃及脫脂等方法萃出回色原因物質，以尋求改善漂白性及控制漂白漿回色之漂白流程。硫酸鹽紙漿以無氯漂白流程。O-Z-E-P-Y可有效漂到理想的白度，但經臭氧處理紙漿粘度的損失甚多。在O-Z-E-P-Y漂白流程中，先行以酵素處理可改善紙漿粘度並且白度可增加1-3% ISO。氧鹼－臭氧漂白漿經過熱水、醇苯萃取及鹼萃處理等處理，PC價依樹種不同有不同程度之降低。紅柳桉紙漿主要影響回色原因物質存在於熱水萃取部分，台灣杉紙漿的熱水抽出物亦為重要影響因子，但醇苯抽出物則佔有相當重要的角色。難漂漿紅柳桉、台灣杉之氧鹼－臭氧漂白漿不論經乾式、溼式加速劣化處理，PC價均隨老化時數增加而增加，以溼式較乾式來得更為明顯。難漂漿的紅柳桉、台灣杉氧鹼－臭氧漂白漿經冷鹼萃取後，銅價及接基隨鹼濃度之增加有下降之傾向，顯示經處理後紙漿中較為活性之官能基減少，因而有較佳之白度及白度安定性。將O-Z-E-P-Y之流程改為O-Z-HE-E-P-Y流程（HE：熱水抽出）能改善難漂紙漿之漂白性及白度安定性。

關鍵字

難漂紙漿 ； 酵素漂白 ； 臭氧漂白 ； 紙漿回色 ； 白度安定性

並列摘要

This study presents the results of a totally chlorine-free bleaching sequence including ozone bleaching and enzymatic treatment of 4 pulps. The treatment results for controlling color reversion of ozone-bleached pulps are also discussed. Oxygen/alkali-treated pulps were enzymatically treated and then subjected to the Z-E-P bleaching sequence. The bleachability and brightness stability of the bleached pulps were also evaluated. Furthermore, after ozone bleaching, hot water extraction, alkali extraction, and alcohol-benzene extraction were performed to elucidate the extractive fractions responsible for color reversion, thus enabling improvement of brightness stability of the resulting pulps. The TCF bleaching sequence (O-Z-E-P-Y) resulted in reasonable brightness and low pulp viscosities due to the ozone treatment. With the TCF sequence including an enzymatic treatment, O-X-Z-E-P-Y, viscosity and brightness of the bleached pulps were improved. When oxygen-ozone (O-Z)-bleached pulps were treated with hot water, alcohol-benzene, and alkali extractions separately, color reversion (PC number) of the resulting pulps decreased differentially, depending on the species of pulp. For red Shorea sulfate pulp, hot-water extractives were assumed to be the main factors responsible for color reversion. But for Taiwania cryptomerioides sulfate pulp, in addition to hot-water extractives, alcohol-bezene extractives also played an important role in color reversion. Results of the accelerated aging tests of O-Z-bleached pulps showed that PC numbers increased with aging time, and wet aging showed a greater effect than did dry aging. Alkali extraction treatment improved the brightness stability of bleached pulps. Increasing alkali concentrations created better improvements. Copper number and carboxylic groups of the resulting pulps decreased with increasing alkali concentrations. Presumably, active groups on the treated pulps were removed by the extraction. A bleaching sequence of O-Z-HE-E-P-Y produced better bleachability and brightness stability in difficult-to-bleach pulps.

並列關鍵字

enzyme bleaching ； ozone bleaching ； brightness reversion ； brightness stability