【作者】 陈蕴智；

【导师】 谢来苏；

【作者基本信息】 天津轻工业学院 ， 制浆造纸工程， 1999， 博士

【摘要】 硫酸铝用作松香施胶的沉淀剂已经有很长的历史了,但它只适用于酸性条件。随着造纸工业的飞速发展,中性施胶越来越显示出其特有的优势,大有取代酸性施胶的倾向。用聚合氯化铝替代硫酸铝与阴离子分散松香胶组成的中性施胶系统充分利用了廉价的松香、在不必对原系统作更多改动的情况下即可实现中性施胶,这一方法具有实用、施胶成本低等许多优点,是适合我国国情的施胶方法。本文以聚合氯化铝和阴离子分散松香胶组成的中性施胶系统为中心,对以下几个方面进行了研究:首先,研究了聚合氯化铝的特性及其影响因素。结果表明,聚合氯化铝的水解、聚合反应受到碱化度、总铝浓度以及制备方法等多方面因素的影响,主要表现在聚合氯化铝中Ala、Alb 和Alc 含量组成的变化。此外,一些环境因素也会影响其聚合形态组成的变化,如聚合氯化铝在水中稀释时,不同的稀释阶段和稀释倍数对其各聚合形态组成之间的转化作用不同;随着pH 值的逐渐升高或熟化时间的延长,聚合氯化铝中各种聚合形态均向着聚合度较高的形态转化。其次,研究了聚合氯化铝在造纸湿部的具体应用,并与硫酸铝从各个角度进行了对比。实验结果表明,用不同的聚合氯化铝作施胶沉淀剂,施胶效果不同;当分散松香胶用量为1.0%,聚合氯化铝用量为0.8%(以Al2O3%计)时,施胶效果较好;一些阳离子性湿部添加剂,如两性淀粉、阳离子聚丙烯酰胺和阳离子湿强树脂PAE 均能不同程度地改善中性施胶的效果,而且两性淀粉和阳离子聚丙烯酰胺的协同作用能进一步改善施胶效果;浆料pH 值对松香施胶影响较大,用聚合氯化铝与阴离子分散松香胶进行施胶,施胶pH 值最高可达到7.5;填料的加入对施胶效果有较大的影响,以重质碳酸钙表现更为明显;此外,施胶效果还受到许多其他因素的影响,如浆料的种类、压榨压力和干燥温度等。不同总铝浓度和碱化度的聚合氯化铝在助留助滤方面没有明显差别,聚合氯化铝、两性淀粉和阳离子聚丙烯酰胺均可不同程度地提高漂白麦草浆纸料的一次留着率和滤水性能,并且,聚合氯化铝与其他带有阳电荷的助留剂协同作用能显著提高漂白麦草浆纸料的一次留着率;此外,搅拌速度对漂白麦草浆的一次留着率有较明显的影响,随着搅拌速度的提高,聚合氯化铝的助留作用显著下降,当与两性淀粉或阳离子聚丙烯酰胺共同使用时,能有效提高其抗剪切能力;接触时间对聚合氯化铝的助留作用影响较小,而对两性淀粉和阳离子聚丙烯酰胺的影响相对较大;几种助剂均在中性范围内具有较好的助留效果,并且聚合氯化铝与两性淀粉或阳离子聚丙烯酰胺的配合使用明显在中、碱性条件下达到较好的留着效果。通过将聚合氯化铝和硫酸铝进行对比实验,可以发现,聚合氯化铝的聚更多还原

【Abstract】 Aluminium sulfate (alum) has been used as the rosin sizing precipitant for along time, but it is only valid in acid pH. With the rapid development of paperindustry, the neutral sizing has shown more and more benefits and tends toreplace the acid sizing. The neutral sizing with anionic dispersed rosin size (DRS)and polyaluminium chloride (PAC) instead of aluminium sulfate makes full useof the cheaper rosin and can be achieved without changing the former acidsystem too much. Being practical and cost-effective, this method is especiallysuitable to our country. The following aspects were studied centering on theneutral sizing system composed of PAC and DRS.Firstly, the characteristics of PACs and the relative factors were studied. It isshown that PACs are formed by hydrolysis and polymerization and thealuminium species are fairly complicated. They are affected by total aluminiumconcentration and preparing methods as well as basicity mainly in differentcomponents of Ala, Alb and Alc. In addition, the aluminium species component isalso affected by some environmental conditions, such as diluting in water,different pH value, aging time and so on. When diluted in water, PACs will bedifferent on aluminium species along with the stages and times of dilution. WhenpH value is increased or aging time is postponed, the aluminium species of PACswill convert to the higher polymer species.Secondly, both of the practice of PAC in wet end and the comparison of PACwith alum in different aspects were studied in detail. The results fromexperiments indicate that different kinds of PAC as rosin sizing precipitant haveshown different contribution to sizing degree. Some cationic additives such asamphoteric starch, cationic polyacrylamide (CPAM) and cationic wet strengthresin PAE can all improve sizing performance in varying degrees and theamphoteric starch is more effective. Furthermore, the coordination of amphotericstarch and CPAM can promote sizing performance. Stock pH is a major factor inrosin sizing. When sized with PAC, available sizing degree can be achieved untilpH is up to 7.5. Fillers are harmful to sizing performance, especially groundcalcium carbonate. Sizing can also be affected by kind of pulp, pressure, dryingtemperature and so on.There is hardly difference among the PACs of different total aluminiumconcentration and basicity as the retention and drainage aids. PAC, amphotericstarch and CPAM can all improve the first pass retention (FPR) and drainage ofstock made from bleached wheat straw pulp to a certain degree. PAC can greatly更多还原