• 펄프종이기술
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• 제44권3호
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• pp.15-21
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• 2012

The optimum dewaxing ratio in dewaxing treatment by the heat and pressure method was investigated by considering aging stability of dewaxed Hanji. Commercial Hanji was coated with beeswax and thermally aged at $150^{\circ}C$ for 24 hours. Then it was dewaxed using the laboratory sheet press equipped with hot plates on both top and bottom sides. Dewaxing ratio was controlled by pressing temperature and time. Four type of dewaxed Hanji samples with different dewaxing ratio were prepared and thermally aged at $150^{\circ}C$. Then the aging stability of dewaxed Hanji samples was evaluated in terms of optical and strength properties. It was found that the aging stability of dewaxed Hanji was superior with higher dewaxing ratio. The result concluded that, in the aspect of aging stability, the coated beeswax in beeswax-treated Hanji shall be completely removed if the coated wax would be dewaxed.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.73-79
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• 2011

The annals of Joseon Dynasty has been known as one of the UNESCO's Memory of the World Heritage. Some of the annals of Joseon Dynasty was composed with wax coated book. Especially the waxed book have been severely damaged by various reason. To find out the safety preservation method of the annals of Joseon Dynasty waxed book, the characteristics of reinforced dewaxed Hanji was evaluated in this paper. From strength properties of MC treated dewaxed Hanji after dewaxing with different method, dewaxing ratio was been high, polymer treated dew axed Hanji showed a better strength. As the aging time, polymer layer on dewaxed Hanji was became brittle and cracked.

• 펄프종이기술
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• 제43권3호
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• pp.66-72
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• 2011

The annals of Joseon Dynasty is one of UNESCO's Memory of the World Register. For the safety preservation of the waxed annals of Joseon Dynasty, the acidic and alkaline aging mechanism of beeswax and beeswaxed Hanji has been investigated. The weight loss of beeswaxed Hanji by the acidic aging was higher than those of alkaline beeswax. The acid value and relative intensity of carbonyl groups in beeswax were slowly increased with aging time. The strength of dewaxed Hanji was decreased with aging time. The significant changes of crystallinity of dewaxed Hanji by acidic and alkaline aging were not observed.

• 펄프종이기술
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• 제43권3호
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• pp.73-79
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• 2011

The annals of Joseon Dynasty is one of the UNESCO's Memory of the World Register. For the safety preservation of wax applied volumes of the annals of Joseon Dynasty, the aging behavior of beeswax and beeswaxed Hanji with $CO_2$, $O_3$, $SO_2$ and $NO_2$ gas has been evaluated. The weight loss of beeswaxed Hanji after aging under ozone gas were increased because of strong acidity of ozone. The acid value and relative intensity of carbonyl groups in beeswax were stabilized with aging time. The physical strength of dewaxed Hanji after ozone aging were rapidly decreased by aging time. The crystallinity of dewaxed Hanji were stabilized at all aging times.

• 펄프종이기술
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• 제44권1호
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• pp.1-9
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• 2012

In this study, 5 solvent soluble polymers were treated on Hanji. Mechanical properties, morphology and oxidation index with thermal aging were measured on the aged Hanji, dewaxed Hanji and polymer treated Hanji. Synthetic polymers(such as polylactic acid, polybutylene succinate, polystyrene) treated Hanji had higher strength and thermal stability than cellulose derivatives(such as cellulose nitrate and cellulose acetate) treated Hanji. Polymer treated Hanji showed a little bit of color change. The oxidation index of PS treated Hanji did not increase with thermal aging because it did not have a carboxyl group in chemical structure. Finally, polystyrene was found to be the most efficient method for strengthening the dewaxed Hanji. The best aging safety and thermal stability were obtained at the polystyrene 3% solution.

• 펄프종이기술
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• 제43권5호
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• pp.1-10
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• 2011

In this study, 13 water soluble polymers(6 natural polymer, 7 synthetic polymer) were treated on Hanji. Mechanical properties, morphology and oxidation index with thermal aging were measured on the aged Hanji, dewaxed Hanji and polymer treated Hanji. 3 natural polymer(such as CMC, EC, MC) and 3 synthetic polymers(such as PVA 1500, 2000, PEG 1500) treated Hanji had higher strength than other polymer treated Hanji. The oxidation index of 3% methyl cellulose solution treated Hanji did a little increase with thermal aging. Finally, methyl cellulose was found to be the most efficient method for strengthening the dewaxed Hanji. The best aging safety and thermal stability were obtained at the methyl cellulose 3% water solution.

• 펄프종이기술
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• 제42권3호
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• pp.58-66
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• 2010

The Annals of beeswax applied-Joseon Dynasty have some serious damages such as cracks, brown, red or black spots, and discolorations by chemical and biological degradation, but others without any beeswax application have still been keeping good quality during over several hundred years. It would be convinced that the beeswax applied in the Annals resulted in these deteriorations. Therefore, in order to focus on the aging mechanism and conservation techniques for the beeswax-applied Annals of Joseon Dynasty, the beeswax applying and dewaxing techniques of Hanji were tried by auto bar coater with a hot plate, and by heat-pressure sensitive extracting treatments. The ageing behaviors of beeswaxed Hanji and dewaxed Hanji were investigated by measuring the changes of physical, optical, morphological, and chemical properties, through accelerated ageing treatment in dry oven at $150^{\circ}C$ during 48 hours. Consequently, the ageing actions of beeswaxed Hanji were even faster than that of Hanji. The optimum dewaxed amounts from beeswaxed Hanji was also obtained in pressure of $40\;kg_f$ under heating conditions.

• 펄프종이기술
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• 제44권6호
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• pp.50-57
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• 2012

In this study, the beeswax extraction methods using organic solvents were examined to develop a optimal dewaxing technology for beeswax-treated Hanji. Thermally-aged beeswax-treated Hanji was dewaxed using four types of extraction methods including dipping, Soxhlet extraction, ultrasonic washing and shaking methods. Then, the aging stability of the dewaxed Hanji was evaluated in terms of variations in paper strength and in the color of the printed area with muk. The experimental results suggested that the dewaxing methods allowing solvent to flow during extraction showed superior extraction efficiency. The dipping method in which the organic solvent does not flow showed the slowest extraction rate of beeswax compared to three other methods. In terms of variations in tensile strength and folding endurance, however, no obvious differences in the aging stability were observed amongst these four extraction methods. Regarding the aging stability in terms of the color of the printed area with muk, Soxhlet extraction method showed the best performance of dewaxing.

• 펄프종이기술
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• 제47권6호
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• pp.130-138
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• 2015

This study was conducted to investigate the effect of the strengthening treatment of methyl cellulose (MC) on properties and aging characteristics of the dewaxed papers during humid heating aging. Beeswax-treated Hanji was dewaxed by the supercritical fluid extraction method, and subsequently the strengthening treatment was performed with MCs having three different viscosities. MC was first applied by dipping a dewaxed paper into a MC solution whose concentration was controlled from 0.5% to 1.5%. After the strengthened papers were artificially aged at $80^{\circ}C$ and 65% RH, the changes in optical and mechanical properties of the samples were evaluated. The results show that viscosity and especially pick-up of MC influenced the strengthening efficiency and aging characteristics of dewaxed paper. Strength was increased with the MC coating weight; in addition, strengthening with MC improved preservability of the dewaxed paper. The optimum conditions for the strengthening with MC was found to be the coating ratio of 4% with 1500 cP MC.

• 펄프종이기술
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• 제42권2호
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• pp.46-52
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• 2010

The annals of Joseon Dynasty has been known as one of the UNESCO's Memory of the World Heritage. The annals of Joseon Dynasty composed with two kind of books, wax coated book and non coated book. Especially the waxed book have been severely damaged by various reason. For the safety preservation of the annals of Joseon Dynasty waxed book, the thermal ageing mechanism of beeswax coated Hanji paper has been evaluated. The weight loss of waxed Hanji were rapidly increased until 30 days in three temperatures(105, 120 & $150^{\circ}C$) and stabilized after 30 days. The acid value and relative intensity of carbonyl groups in beeswax were increased with strong conditions. This means that the deterioration of beeswax should be progressed with oxidizing reaction. The physical strength and the crystallinity of dewaxed Hanji were decreased with ageing time.