• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.37-42
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• 2006

The paper discusses the combined use of softwood and eucalyptus kraft pulps in the production of printing and writing papers. Looking for process and paper quality optimization, refining pilot plant trails were carried to identify the effects of refining type (mixed or separate) and intensities (specific edge load), and also furnish composition (amount of each pulp in mixture) on final paper quality and process costs. The basic effects on pulp fibers were evaluated against paper quality properties, such as physical strengths, bulk, vessel picking, opacity and porosity, as well as the interactions with papermaking process, such as estimates of paper machine runnability, paper breaks and industrial refining control. The results show that the furnish composition and the type of refining has a significant effect on properties related with both final paper quality and total costs. The best alternative for printing and writing papers was identified for mixed refining, under the lowest refining intensity, and with the highest dosage of eucalyptus pulp.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.3
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• pp.47-54
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• 2015

In this study, effects of kneading treatment on the properties of hardwood bleached kraft pulp (HwBKP), softwood bleached kraft pulp (SwBKP) and hardwood bleached chemi-thermo-mechanical pulp (HwBCTMP) were elucidated with a laboratory two-shaft kneader. Kneading treatment was performed at 30% (w/w) of pulp concentration and the number of passes through the kneader was adjusted from 0 to 10 passes. Then, changes in properties of pulp fibers were evaluated. It was found that fiber characteristics were influenced by kneading treatment. Fiber length was decreased with kneading while other morphological properties such as fiber width, curl and kink became increased as the number of passes through the kneader increased from 0 to 5 passes. The magnitude of changes in the morphological properties of softwood chemical pulp was the largest, followed by hardwood chemical pulp. The morphological properties of HwBCTMP were little influenced by kneading treatment. Swelling of fiber measured by WRV was increased with kneading except of HwBCTMP.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.5
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• pp.20-25
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• 2009

Residual extractives had a noticeable impact on the brightness of unbleached hardwood kraft pulps (trembling aspen). The brightness-impacting extractives were effectively removed by oxygen delignification. In addition, oxygen delignification was more effective in removing chromophores in hardwood unbleached kraft pulps than in those of softwood (loblolly pine). The residual extractives in unbleached hardwood kraft pulps also affected the pulp color, primarily redness and the L value. These redness-related extractives in unbleached hardwood kraft pulps were also effectively removed by oxygen delignification. There were no significant color differences between untreated and solvent-extracted oxygen-delignified aspen kraft pulps. The residual extractives in unbleached and oxygen-delignified softwood (loblolly pine) kraft pulps did not have a significant impact on either brightness or pulp color.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.37-42
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• 2003

Physical properties of paper can be explained in terms of the changes in fiber's morphological properties. As the paper machine speed increases, the basis weight decreases and the mixing ratio of inferior recycled fibers increases, paper break becomes important than ever before. One of the objectives of this study is to analyze paper's physical, mechanical and fracture mechanical properties depending on softwood(SW) and hardwood(HW) mixing ratios and recycling. Fibers were refined by Valley beater to 450 mL CSF. Handsheets of 30 g/$\textrm{m}^2$ were prepared at different mixing ratios. Fracture toughness was measured as the amount of energy applied to cracked sample before total failure. Fracture toughness showed different trend to other strength properties. At the mixing ratio of SW 80: HW 20, papers showed the maximum fracture toughness. At this mixing ratio, flexible softwood fibers were mostly broken and stiff hardwood fibers were mostly pulled out.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.99-107
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• 2012

In this study, the lumen loading technology for preparing magnetic papers were evaluated. The rice husk fiber, softwood kraft pulp, hardwood kraft pulp were applied and the morphological properties of pits on the those fibers were investigated with SEM. The softwood kraft pulp had the bigger size of pits, $3{\sim}5{\mu}m$ in diameter, which resulted in higher loading amount. The comparison of two methods for lumen loading such as the low concentration method with the disintegrator and the high concentration method with the Hobart mixer showed the Hobart mixer could resulted in the higher efficiency. The conditions of lumen loading process such loading time, addition amount of metal particles and addition of PEI were also evaluated. The magnetic hysteresis loop of handsheet samples made of lumen loaded fiber with $Fe_3O_4$ and $Fe_2O_3$ were examined. The differences in magnetic properties could be found according to the ferrite types.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.362-368
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• 2018

Purpose: Self-sufficiency in paper production is desired in Nigeria. This study was aimed at evaluating the performance of a locally fabricated batch pulp digester. Methods: The pulp yields of sheaths generated as waste in the production of bamboo (Bambusa vulgaris) laminates were determined at different liquor concentrations and treatment time after preliminary experiments to ascertain the conditions under which the sheath started to pulp. Moreover, the optimum pulping conditions and fiber characteristics were determined and estimated, respectively, to ascertain the pulp fiber suitability for paper production. Results: An optimum pulp yield of 65.1% was obtained at 50% NaOH and 25% $Na_2S$ liquor concentration (w/w) when the cooking time was 4 h. The results of fiber characterization of the pulp indicated an average fiber length of 2.19 mm with a low Runkel ratio of 1.63, both of which signify the suitability of the pulp for medium quality paper production. Conclusions: Softwood pulp can be blended with the fibers to improve the strength of the produced paper; further investigation should be carried out to use other non-woody plants for pulp and papermaking.

• Journal of the Korean Wood Science and Technology
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• v.20 no.3
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• pp.67-78
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• 1992

The application of white-rot fungi to pulping and bleaching processes has been studied at the Wood Chemistry Laboratory in Kyushu University, cooperatively with the Biotechnology Laboratory of Kobe Steel, Ltd. Some successful results of the studies for a biomechanical pulping process, biobleaching of hardwood and softwood kraft pulp, as well as chlorine free biobleaching of oxygen-prebleached hardwood kraft pulp are dealt with. Biological treatment of the pulp bleaching effluent is also described.

• Journal of the Korean Graphic Arts Communication Society
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• v.30 no.3
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• pp.57-64
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• 2012

When papers each made with sea-algae pulp 1%, 5% and soft, hard wood pulp were aged for 12days. Paper made with soft wood pulp is 30% loss of folding endurance, made with hard wood pulp is 50% loss of folding endurance. On the other, papers each made with 9% sea-algae pulp and soft, hard wood pulp were 18% loss of folding endurance. In the aging test of paper made with different freeness paper made with 300ml CSF, is more effective than 400ml CSF, 500ml CSF.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.231-237
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• 2006

Grease barrier food containers are commonly used for packaging of fast food, cooked food, and food in general. Greaseproofing is also used for certificate paper and label paper etc. Different pulp raw materials, due to their different fiber morphology and chemical compositions, produce papers of varying characteristics. We used optical photomicroscopy and fiber analysis data to evaluate fiber morphology and traits under various beating conditions in order to understand which pulp raw materials produced superior greaseproofing property when a fluorinated greaseproofing agent was added internally. The experiment studied 9 species of pulps, including 2 softwood (northern pine and radiata pine) bleached kraft pulps which were beaten to 550 and 350 mL CSF, respectively; 3 hardwoods (eucalypts, acacia, mixed Indonesian hardwoods) bleached kraft pulps which were beaten to 450 and 250 mL CSF, respectively; and nonwood fibers of reed, bagasse, and abaca. A fluorinated greaseproofing chemical at 0.12% dosage with respect to dry pulp was added to each pulp preparation and formed handsheets. A total of 67 sets of handsheets were prepared, and their basis weights, thickness, bulks, opacities, wet opacities, air resistance, water absorption and degrees of greaseproofing were measured for an overall evaluation of pulp and freeness on greaseproofing papers. The experimental fiber length, coarseness and distribution characteristics and the greaseproofing results suggest that softwood pulps (radiate pine > northern pine) were superior to hardwood pulps (eucalypts > acacia > mixed Indonesian hardwoods). The unbeaten pulps gave papers with high porosities and nearly devoid of greaseproofing property. Greaseproofing is proportional to air resistance. Among the nonwood fibers, bagasse had the best greaseproofing property, followed by reed and abaca was the poorest. With regards to waterproofing property, hardwood pulps (mixed Indonesian hardwoods > acacia > eucalypts) were better than softwood pulps (northern pine > radiate pine). Among the Nonwood fibers, reed had the highest waterproofing property, and it was followed by abaca, while bagasse had the poorest waterproofing characteristic. In summary, bleached kraft northern pine, eucalypts and reed pulps were best suited for making greaseproofing papers, Freeness of the pulps should be kept at $200{\sim}280mL$ CSF for optimal performance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.38-45
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• 2015

Fold cracking is one of quality troubles of coated papers. In this study, the fold cracking of high grammage ($250g/m^2$) coated paper made with the different pulp composition and layer structure of base paper was investigated. The single layered, high grammage base paper was prepared by mixing of hardwood and softwood bleached kraft pulp fibers with the different ratios. The high grammage coated paper showed the higher fold cracking than low grammage coated paper because of the increase in thickness. The increase in the content of softwood pulp fibers reduced the fold cracking in the case of high grammage coated paper. When the creasing process was conducted before folding process, the fold cracking of coated paper decreased. By manufacturing the base paper with multiply structure, the fold cracking of coated paper could be reduced significantly, especially when the BCTMP and OCC were used as a middle layer and the creasing process was carried out. The delamination of layers in base paper affected the fold cracking positively.