【作者】 杨静；

【导师】 万金泉；

【作者基本信息】 华南理工大学 ， 制浆造纸工程， 2012， 硕士

【摘要】 近年来，在造纸工业中因植物纤维原料的短缺和降低成本的需要，不少厂家使用OCC再生纤维来生产瓦楞原纸。瓦楞原纸作为生产瓦楞纸板重要的组成材料之一，因其特殊的用途而需具备较好的强度性能和抗潮性能，在造纸过程中可以加入施胶剂满足人们对瓦楞原纸强度和抗潮方面的要求。然而OCC再生纸浆经历了制浆造纸的工艺过程，和原生植物纤维相比，其浆料特性有较大区别。再生OCC纸浆中含有较多的细小纤维、填料以及添加剂等等，这些物质都会影响AKD施胶的效果。本论文以OCC废纸浆为研究对象，研究了AKD施胶剂用于OCC废纸浆施胶的影响因素，为废纸浆的施胶工艺优化提供理论支持，并且从表面化学的角度来研究AKD与纸浆纤维的作用机理，从微观的角度来分析施胶对回用纤维性能的影响。本文将针叶木纸浆和OCC纸浆对比，研究了OCC废纸浆的可施胶性，同时研究了AKD施胶剂的各项性能指标。研究发现：OCC纸浆中的大部分纤维长度都在1.0mm以下，细小纤维含量较多；经筛分过的纤维，目数在100-200之间的纤维具有较好的可施胶性。OCC纸浆和针叶木浆相比，加入相同的助留剂时，后者总比前者先达到等电点。并且，针叶木浆的阳离子需要量远小于废纸浆。另外废纸浆中含有较多的填料也对施胶产生了一定的负面影响。本文中所用的AKD粒径分布均匀，Zeta电位为30mv左右，AKD活性蜡体含量为11%，乳液的水解率为15.2%，AKD的熔点为47°C。另外，本文还研究了OCC废纸浆施胶的影响因素，经研究发现：当AKD用量为0.3%时，经OCC纸浆抄造的纸张Cobb值达到30g/m2左右。纸浆中加入滑石粉和PCC时，都会降低纸张的施胶效果，但PCC的负面影响更大。同时施胶顺序也会影响到施胶效果，CS+AKD+PCC的加料顺序使纸张具有最好的抗水性能。干燥条件也是施胶效果的一个重要影响因素，在100°C的干燥条件下干燥10min左右，AKD与纤维的反应基本可以完成，此时纸张具有较好的抗水性能。在施胶过程中加入的CS和CPAM除了能提高AKD在纤维上的留着率，还对纸张的物理性能以及透气度等性能产生明显影响CS和CPAM的效果类似，都存在一个临界值，在临界点时，纸张的强度性能和透气度、匀度都较好，而一旦超过这个临界点，纸张的性能将会下降。加入填料，纸张的强度下降，透气度上升。当加入10%PCC时，纸张的性能还能保持较好，但是当填料用量增加到20%后，纸张的性能就会大幅度下降。提高干燥温度和延长时间，纸张的施胶效果逐渐改善。当温度从70°C升高到130°C、时间从5min延长到30min时，所测得纸张的抗水性能分别提高了49.3%和48%。并且随着干燥温度的提高和干燥时间的延长，纤维之间的交织更为紧密，因而成纸的强度也会增加。在温度为100°C、时间为15min时，成纸的强度较好。但是温度过高和时间过长时，也会引起纤维的角质化现象，从而降低成纸的强度。本文采用AFM、SEM、XPS、红外光谱、表面接触角等分析测试方法研究了AKD施胶后OCC纤维的性质变化情况。从AFM和SEM图片中可以看出经AKD施胶的纤维光滑而平整，均方根粗糙度由未施胶时的27.949nm变为12.811nm。红外光谱和XPS的分析表明AKD与纤维生成了O=C-O化学键。AKD除了跟纤维反应而使纸张具有抗水性以外，还有一部分是覆盖在纤维上。接触角的测试表明Cobb值小的纸张具有较好的抗水稳定性。另外，从施胶后纤维性能变化的角度来看，经AKD施胶的纤维孔隙下降，保水值也呈略微下降趋势。纤维保水值下降的原因可以从两方面来解释：施胶后纤维孔隙的累积孔容和平均孔径下降，能通过纤维的孔隙进入到细胞腔中的水份相应减少，从而使得纤维的润胀能力下降；另外浆内施胶会降低水分子在纸张中的渗透速度，甚至会阻碍其通过纤维的孔隙结构进入，因此纤维的润胀能力也会下降。更多还原

【Abstract】 In many papermaking mills, corrugated paper was made from OCC (old corrugatedcontainer) recycled fiber due to the shortage of plant fibrous material and the demand of costreduction in recent years. Corrugated paper is the major part in corrugated paperboard, itshould possess the quality of good strength and water-resistance properties for its applicationof packing. Generally speaking, sizing agent is added in papermaking process to improve thewater-resistance of corrugated paper.However, OCC recycled fiber has experienced the process of pulp and papermaking,contains more fines, fillers, auxiliary chemicals and other impurities compared to originalwood pulp, which will affect the effect of sizing.The sizing ability of OCC pulp, softwood pulp as control sample, and the performance of AKDwere studied, It was found that there are many fines in OCC, most fiber are shooter than1.0mm and fibersbetween100and200mesh sizes shows better sizing ability。Comparing with softwood pulp，OCC pulparrived isoelectric point slowly when added same dosage amount of retention aid，the cationic demand ofOCC pulp was higher than that of softwood sulp, and fillers in waste paper stock also give a certainnegative effects on sizing. AKD agent used in this paper shows even particle size distribution， the Zetapotential was about30mv，the active wax content was11%， the hydrolytic ratio was15.2%and themelting point was47°C。Moreover, the influence factors of sizing on OCC pulp were also studied, When the usage of AKDwas0.3%, the cobb value of paper was about30g/m2. Both talc powder and PCC will produce negativeeffects on sizing, and the latter give greater effect. The sequence of sizing will also affects sizing, thesequence of CS+AKD+PCC achieved best water resistance. Another significant factor is drying condition,the action between AKD and fiber completed in10min under the temperature of100°C, so the paper hasgood water resistance. The addition of CS and CPAM increased the retention of AKD, and obviouslychanged the physical properties of paper. For CS and CPAM, the effects of them on physical propertieswere similar, there was a critical value in the trend of physical, the paper strength properties, permeabilityand evenness got better before achieving the critical value, but once beyond this critical point, theperformance of the paper will be reduced. Fillers reduced the strength properties of paper, however, the airpermeability of paper was increased by the addition of fillers. When the addition of PCC was10%, therewas no obvious strength properties damage of paper. However, when the addition of PCC was increased to20%, the strength properties of paper were decreased sharply. With the increasing of drying temperatureand time, the sizing effect of paper improved gradually. When the drying temperature increased from70°Cto130°C and the drying time increased from5min to30min, the water resistance of paper increased49.3%and48%respectively. With the increasing of drying temperature and time, bounds between fibersgot more tightly, and the strength properties of paper were improved. The optimal drying temperature was 100°C for15min. Too higher drying temperature and too long drying time will caused fiber hornificationand induced the damage of paper strength properties.In this thesis, the influence factors of Alkyl ketene dimer (AKD) sizing agent used inOCC recycled fibers were studied, and it expected to provide theoretical foundation for sizingtechnics optimization of recycled fiber. Furthermore, the reaction mechanism between AKDand fibers was studied form the standpoint of surface chemistry, and the influence of sizing onrecycled fiber properties was analysised from the view of microscopic. The main innovativepoint of this paper is that the relation between AKD sizing and micro properties of fiber wasestablished from the angle of surface chemistry. The water-resistance of paper obtained for thereaction of AKD and fiber and the coverage of AKD on the surface of fiber. It was confirmedthat paper with lower Cobb shows better stability of water-resistance by surface contactingangle test, the porosity and WRV(water retention value) of fiber were also decreased aftersizing. The reasons of the decline of WRV can be explained as following: the decrease ofcumulative pore volume and average pore diameter of fiber after sizing lead to the decrease ofmoisture entered to lumen through holes in fiber, and the movement of permeability of watermolecules in paper was obstructed or stopped by internal sizing, so the swelling ability offiber was decreased.更多还原