難漂化學紙漿的臭氧漂白

本論文在不同紙漿含水率、不同臭氧濃度（高濃度）之條件下探討難漂白化學紙漿之漂白，由其臭氧消耗率（消耗量／添加量）、單位臭氧的白度提昇、單段漂白白度等評估漂白效益，並選用無氯元素漂白流程Z-E1-D1-E2-D2，以瞭解難漂化學臭氧漂的可行性，同時針對臭氧漂白易損傷纖維的性質，進一步探討pH值及酸保護劑對臭氧漂白影響。臭氧漂白於含水率40-60%時有最火的反應性，漂白紙漿有最佳的單位臭氧的白度提昇、最低卡巴偵及較低程度的黏度損失。臭氧消耗率隨紙漿含水率增加而增加，含水率65%達到最高。Z-E1-D1-E2-D2流程可處理難漂漿的問題，闊葉樹難漂紅柳按漿經D1漂段後白度已達80%ISO以上。針闊葉樹無論偽難漂漿與否，在Z-E1-D1-E2-D2漂白流程中，白度均可漂至85%ISO以上；臭氧漂白在低pH值時可抑制纖維素的膨潤性，降低對臭氧的反應性，而達較佳的漂白性，酸保護劑亦有類似的機制，其中以丙酸其最佳之保護效果。

關鍵字

化學漿漂白；無氯漂白；臭氧紙漿；難漂紙漿

並列摘要

This study investigated the influence of ozonation on the bleachability of the sulfate pulp of certain hard-to-bleach woods (Shorea albida and Taiwania cryptomerioides). Ozone consumption, pulp brightness, and pulp viscosity were measured at different pulp moisture contents and ozone concentrations. An ECF (elemental chlorine-free) bleaching sequence Z-E1-D1-E2-D2 for the hard-to-bleach pulps was also conducted.
The greatest ozonation reaction took place at moisture content levels of 40-60%. At these levels, the resulting pulps attained the highest brightness, lowest kappa number, and a medium degree of viscosity loss. The higher the moisture content was, the greater the 03 consumption. Maximum O3 consumption was elicited at 65% moisture content.
The 3-stage Z-E1-D1 sequence can easily provide satisfactory brightness with S. albida pulp exceeding 80% Iso even in the D1 stage. The brightnesses of all hard-to-bleach wood species were over 85% ISO after the Z-E1-D1-E2-D2 bleaching sequence.
At low pH, swelling of cellulose is inhibited. Therefore the reactivity of cellulose with ozone is reduced, resulting in a better bleaching effect with ozonation. Acidic protective additives showed the same effect as well.

並列關鍵字

chemical pulp bleaching ； non-chlorine ； zone bleaching pulp ； hard-to-bleach pulp

國際替代計量

難漂化學紙漿的臭氧漂白

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