低分子质量HACC在废纸造纸中的应用研究

Study on the Application of Low-molecular Weight HACC in Recycled Paper Production

关键词:  HACC  Zeta电位  阳离子需求量  残余油墨  留着率

Key Words:HACC  Zeta potential  cationic demand  residual ink  retention

摘要:本文主要探讨了低分子质量壳聚糖季铵盐(HACC)在废纸脱墨浆中用作阴离子垃圾捕集剂(ATC)的湿部化学效应,并与聚胺(PA)、聚合氯化铝(PAC)等传统ATC进行比较,通过纤维表面Zeta电位、阳离子需求量、残余油墨含量、留着率及成纸性能的变化对其进行表征,以开发新型的ATC,有效缓解造纸机运行性能和成纸物理性能与阴离子垃圾之间的矛盾。结果表明,HACC是一种有效的ATC,对阴离子垃圾捕集效果较好,当用量为0.10%时,能有效去除废纸脱墨浆中70%以上的阴离子垃圾,且纤维表面Zeta电位变化较小。此外,因其独特的多羟基、胺基结构及对纤维的直接性,能有效固着残余油墨和细小组分于纤维表面,减少湿部沉积物。而较高分子质量的2^# HACC较1^# HACC更适合用作ATC,与PA、PAC等相比,能有效地降低阴离子垃圾对成纸物理性能和造纸机运行性能的负面影响。

Abstract:In this paper, the wet end chemical effects of low-molecular weight 2-hydroxypropyl trimethyl ammonium chloride chitosan (HACC) used as anionic trash collector in recycled paper making, in terms of fiber surface Zeta potential, cationic demand, the residual ink content, retention value and mechanical and optical properties of the handsheets were studied and the comparsion with traditional PA and PAC trash collectors was conducted. The aim of the research was to develop a new kind of ATC which could effectively alleviate the problems of paper machine runnability. The results showed that HACC was a more effective ATC than traditional PA and PAC with trapping more anionic trash. When the dosage of HACC was 0.1%, more than 70% of the anionic trash of deinked pulp was effectively removed while the surface Zeta potential of fibers was nearly unchanged. In addition, HACC had some favorable properties such as large amount of hydroxyl groups, and special amine structure, which would effectively enable residual ink and fines to be fixed onto the surfaces of pulp fiber, and reduce the wet end sediment. The 2^# HACC with higher molecular weight was more suitable to be acted as ATC than the 1^# HACC, compared with the traditional ATC, which was more effective to reduce the negative impacts on the physical properties of handsheets and paper machine runnability caused by anionic trash than traditional ones.