• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.3
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• pp.15-21
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• 1998

Crude enzymes of Trichoderma viride and Phanerochaete chrysosporium were evaluated for their effect to brightness and physical properties of recycled pulp from newspaper and corrugated container board. The brightness of recycled pulp from newspaper increased with crude enzymes from Trichoderma viride and Phanerochaete chrysosporium. The brightness of recycled pulp of corrugated container board increased with crude enzyme from Phanerochaete chrysosporium, but decreased with crude enzyme from Trichoderma viride. The Δbrightness with chemical bleaching of crude enzyme treated pulp was lower than that of heat killed enzyme treated pulp, but the final brightness of pulp was increased. Modification of recycled paper with crude enzymes can result in a substantial increase in physical properties with little no loss in pulp freeness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.5
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• pp.86-94
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• 1999

Alkaline peroxide bleaching of chemi-mechanical pulp is a very complicated system where various process factors affect the bleacing performance and pulp properties. Traditional onefactor-at a time method is ineffective and costly infinding the optimal bleaching conditions. In this study, statistical experimental design and multiple regression method wre used to investigated the interactions among various bleaching factors and to find out the possbile maximal brightness development during one stage alkaline peroxide bleacing of TMP. The TMP was made from 10% Korean red pine and 90% Korean spruce and had an initial brightness of 54.5% ISO. the TMP was pretreated with EDTA(0.5% on O.D. pulp, 3% pulp consistency, 30$^{\circ}C$ for 60 minutes) and bleached in a 2 L Mark V Quantum Reactor at 750 rmp, 7.5% of bleaching consistency and with 0.05% magnesium sulfate addition. The ranges of chemical factors studied , based on oven-ried pulp, were 1-5% for hydrogen peroxide, 1-4% for sodium hydroxide and 1-4% for sodium silicate. The rages of reaction temperature and time were 50-90$^{\circ}C$ and 40-180minutes respectively. Interactions of hydrogen peroxide with alkali , time with temperature ature, alkali with time and silicate with temperature were found to be significant which means that hydrogen peroxide bleaching will be favored at stable concentration of perhydroxyl ion, relatively short time and low temperature, and high level of silicate. Mathematical model which has good predictability for target brightness in one stage peroxide bleaching can also be established easily. Base ion the model, maximal brightness of 70% ISO was found to at 50$^{\circ}C$ and 50 minutes by chemical additions of 5% for hydrogen peroxide, 3.2-3.4% for sodium hydroxide and 4% for silicate based on O.D. pulp. However, this result might not be suitable for situation where furnishes are different from ours, or different pretreatment is used, or bleaching carried out at different pulp consistency. In these cases it will be good to re-investigate the process by a similar methodology as was used in this study.

• Journal of the Korean Wood Science and Technology
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• v.20 no.4
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• pp.57-64
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• 1992

The unique cell wall micropores of pulp fiber can be utilized as loading site in variety of important practical application which could be the basis of new papermaking technologies. One of these includes the manufature of paper containing higher levels of in situ filler precipitated. Hardwood pulp fiber were first impregnated with the solution of sodium carbonate($Na_2CO_3$). The micropores in cell wall of pulp fibers were filled with the liquid salt solution. The second calcium nitrate($Ca(NO_3)_2$) solution formed an insoluble calcium carbonate($CaCO_3$) precipitate within the cell wall micropores by interacting with the first sodium carbonate solution. The effects of chemical concentration and dryness of pulp fibers on the retention of cell wall micropore loaded filler were investigated. The paper properties of cell wall micropore loaded pulp fibers were compared with those of conventionally loaded and lumen loaded pulp fibers. Also the presense of the fillers within the cell wall micropore was observed by SEM. Increasing the chemical concentration to generate the calcium carbonate increased the retention of filler in cell wall micropore loaded pulp fibers. The particle size distribution of precipitated calcium carbonate ranged from $0.1{\mu}m$ to $80{\mu}m$. But, the average particle size of cell wall micropore loaded calcium carbonate was $4{\mu}m$. The paper made from never dried pulp fibers, the cell wall micropores which were filled with calcium carbonate, had better mechanical and optical properties than those of conventionally loaded or lumen loaded pulp fibers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.4
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• pp.16-20
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• 2013

Yellow poplar grown in Korea and imported eucalyptus were compared their kraft pulping characteristics and evaluated the replacing possibility of eucalyptus by yellow poplar. Difference between yellow poplar and eucalyptus were investigated in chemical composition and fiber morphology. Yellow poplar kraft pulp resulted in the higher yield, longer fiber length and thicker fiber, and higher pulp strength than that of eucalyptus. More xylan survived in eucalyptus than yellow poplar during kraft pulping, which led to similar pulp yield even though polysaccharides in Eucalyptus was 4.5% less than in yellow poplar. Longer and thicker yellow poplar pulp fiber resulted in better beating response and pulp strength properties.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.5
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• pp.25-29
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• 2001

Dimethyldioxirane (DMD), which is a source of active oxygen, is effective agent that can be used in chemical pulp bleaching. In this study, delignification of kraft bagasse pulp has been carried out by using DMD. The effect of the applied charge of DMD (as active oxygen) and pH of the delignification medium were studied. The optimum conditions of the applied DMD charge and pH of the delignification reaction were achieved at pH range from 8~9, 2% of DMD (as active oxygen) and the rest of delignification reaction conditions were $25^{\circ}C$, 60 min, and 12% pulp consistency. The development of brightness per unit kappa number removal (ΔBrightness/ Δ Kappa number) has highest value at the optimum condition. The study showed that the reactivity of kraft bagasse pulp be enhanced to wards alkaline hydrogen peroxide bleaching by pulp treatment with DMD.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.05a
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• pp.87-122
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• 2008

In order to manage the papermaking procedure in an effective way, it is inevitably required to measure and estimate the various changing parameters of wet-end process control. This content is devoted to the explanation of lab scale new investigating method regarding wet-end process of paper machine by using RDA.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.83-89
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• 1999

Bast fibers of paper mulberry ( Broussonetia Kazinoki Sieb) were cooked with a weak alkaline salt, potassium carbonate which has been known as a major inorganic component of the traditional lye, and its cooking characteristics were investigated . The bast fiber was easily cooked by potassium carbonate. The pulp yield was rapidly decreased up to 20-30 mol of potassium carbonate, but the Kappa number was slowly decreased with increasing of potassium carbonate. The potassium carbonate pulps were easily defibered at low cooking chemical charge of 25mm on and high pulp yield of about 80%. These results were confirmed that pectin was easily removed during the potassium carbonate cooking. In contrast, when sodium carbonate was used as a cooling agent, the bast fiber was only partially defibered. Thus, sodium carbonate was a less effective cooling chemical of the bast fiber. The results of this experiment indicated that potassium carbonate could not only be used as a good cooling agent of bast fiber, but also as an alternative agent of sodium hydroxide.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.93-97
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• 1999

Tobacco stalks are greatly produced as annual agricultural wastes. These residues are available approximately 70,000 tons per year. This study was performed to evaluate the potentials of tobacco stalks as a new resource for reconstituent tobacco sheet. Tobacco stalk was more lignified than cereal straws, and had similar chemical constituents to hardwood. Pulping yields by cooling at 170$^{\circ}C$ of dry and green tobacco stalks were 56.7% and 66.3% , respectively. Around 50$^{\circ}$SR freeness level of mixed pulp was adjusted by mixing more than 10% chemical pulp9CP) in the case of dry tobacco stalk and more than 15% CP with wet one. By immersing this handsheet in extracted cooking liquors, reconsitutent sheet contained about 0.28% of nicotines could be prepared. This sheet had enough strength properties for cigarette paper making . In conclusion, it was proved that tobacco stalk could be used to produce the reconstituent tobacco sheet.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.109-114
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• 1999

The deposition kinetics of fines on fibres was studied to elucidate the flocculation mechanism of a PAM/bentonite retention aid. It is shown that polymer-induced co-flocculation is not permanent. This phenomenon is attributed to a stabilising effect of polymer transfer between surfaces. The resulting polymer layers have a reduced bridging ability with naked surfaces. The addition of bentonite increases the bond strength between fibres and fines, and links non-briding layers. These results explain the positive influence of bentonite on fines retention.

• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.42-46
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• 1963