Abstract

Low consistency (LC) refining of (chemi-)thermomechanical pulp (TMP) provides an energy efficient alternative to high consistency refining for pulp property development. However, the benefit of LC refining is often limited by excessive fibre shortening, lower tear strength and a reduction of bulk caused by the refining process. In this study, microfibres produced by LC refining of TMP and kraft pulp fibres were investigated for their reinforcement potential in high freeness mechanical pulp. Primary pulp at 645 mL Canadian Standard Freeness was LC refined to different energy targets as a baseline for mechanical and optical property development. In contrast, the same primary pulp was reinforced with different microfibre types in ratios that yielded the same specific energies of the baseline LC refined pulp. The study revealed that at equivalent energies, the addition of TMP microfibres to the high freeness primary pulp displayed tensile development identical to the LC refined pulp, with significantly improved tear and bulk. The addition of kraft microfibre to primary pulp produced the highest tensile and tear strength but compromised light scattering. Additionally, all microfibre composites showed improved elongation, as opposed to no notable change in elongation with conventional LC refining. This investigation proposes an alternative, cost-effective approach for developing high bulk, high strength mechanical pulp by limiting the extent of second stage refining and using LC refined microfibres for pulp reinforcement. The high tear–high bulk open construction of the composite paper is likely to benefit boxboard and packaging applications.

中文翻译：

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低浓度精制木质纤维素微纤维：高体积，撕裂和拉伸机械浆纸的MFC替代品

摘要

（化学）热机械纸浆（TMP）的低浓稠度（LC）精制为纸浆性能开发提供了高浓稠度精制的节能替代方案。但是，LC精制的好处通常会因精制过程引起的纤维过度缩短，撕裂强度降低和体积减小而受到限制。在这项研究中，研究了由TMP的LC精制生产的微纤维和牛皮纸浆纤维在高游离度机械浆中的增强潜力。将645毫升加拿大标准游离度的原浆进行LC精炼，以达到不同的能量目标，以此作为开发机械和光学性能的基准。相反，相同的初级纸浆以不同的微纤维类型按一定比例增强，从而产生与基线LC精制纸浆相同的比能。研究表明，在同等能量下，向高游离度初级纸浆中添加TMP微纤维显示出与LC精制纸浆相同的拉伸强度，并显着改善了撕裂度和膨松度。在原浆中添加牛皮纸微纤维可产生最高的拉伸强度和撕裂强度，但会影响光散射。此外，与传统的LC精炼方法相比，伸长率没有明显变化，所有微纤维复合材料均显示出改善的伸长率。这项研究提出了一种可替代的，具有成本效益的方法，可通过限制第二阶段的精炼程度并使用LC精制的微纤维增强纸浆来开发高体积，高强度的机械纸浆。复合纸的高撕裂度，高散度开放结构可能有益于纸板和包装应用。在高游离度初级纸浆中添加TMP微纤维显示出与LC精制纸浆相同的拉伸强度，并显着改善了撕裂度和膨松度。在原浆中添加牛皮纸微纤维可产生最高的抗张强度和撕裂强度，但会影响光散射。此外，与传统的LC精炼方法相比，伸长率没有明显变化，所有微纤维复合材料均显示出改善的伸长率。这项研究提出了一种可替代的，具有成本效益的方法，可通过限制第二阶段的精炼程度并使用LC精制的微纤维增强纸浆来开发高体积，高强度机械浆。复合纸的高撕裂度，高散度开放结构可能有益于纸板和包装应用。在高游离度初级纸浆中添加TMP微纤维显示出与LC精制纸浆相同的拉伸强度，并显着改善了撕裂度和膨松度。在原浆中添加牛皮纸微纤维可产生最高的拉伸强度和撕裂强度，但会影响光散射。此外，与传统的LC精炼方法相比，伸长率没有明显变化，所有微纤维复合材料均显示出改善的伸长率。这项研究提出了一种可替代的，具有成本效益的方法，可通过限制第二阶段的精炼程度并使用LC精制的微纤维增强纸浆来开发高体积，高强度的机械纸浆。复合纸的高撕裂度，高散度开放结构可能有益于纸板和包装应用。