• 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.

• Journal of the Korean Wood Science and Technology
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• v.23 no.3
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• pp.23-27
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• 1995

Several characteristic results of physical and optical properties of paper treated by UV light were obtained in the previous papers(Kim et al. 1988). In this paper, folding endurance and brightness of paper prepared by spraying photostabilizer were examined in order to elucidate photodegradation phenomena, UV light absorber and radical scavenger were most effective in preventing of folding endurance decrease. These results may be indicated that depolymerization of cellulose and hemicellulose chains leading to degradation of paper mechanical properties mainly caused by radical reaction. Ineffective hydroperoxide decomposer may be explained because of auto-oxidation reactions before forming stable compound from hydroperoxide.

• Journal of Conservation Science
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• v.37 no.6
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• pp.689-700
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• 2021

This study aims to optimize the measurement conditions of handmade Hanji paper to reduce the time required for measurement while meeting folding endurance standards, for various basis weights. Thirteen types were selected, including 12 types of Hanji with grammages of 17 g/m², 30 g/m², and 45 g/m², and one type of 75 g/m² copy paper, and 24 sheets were prepared in the laid and chain directions. Subsequently, folding endurance experiments at different load (14.72 N, 9.81 N, 4.91 N) and specimen width conditions (15 mm, 10 mm, 5 mm) were performed, using a 4-MIT folding endurance tester. The results showed that, for specimen widths of 15 mm and 10 mm under a load of 4.91 N, the folding endurance falls within the reference range (10~10000 times). In particular, reduced folding endurance range and measurement time were observed at a width of 10 mm under a load of 4.91 N. Moreover, the endurance trend lines based on the average values of load and specimen width ranges enabled the prediction of the folding endurance within those ranges, according to the decreasing slope. Furthermore, for a specimen width of 15 mm under a load of 4.91 N, the folding endurance in the comparison group (35 to 17723 times) significantly exceeds the upper limit of the reference range (10~10000 times). Therefore, the measurement conditions of 4.91 N with a specimen width of 10 mm are proposed.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.1
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• pp.55-59
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• 2011

Folding endurance, bending fatigue and monotonic tensile tests of 4 kinds of Cu foil on flexible substrate was performed to investigate the relationship between folding or bending endurances and tensile characteristics. The repeated 5.3 or 2.0% strain was applied to Cu foil in folding endurance test or bending fatigue test while monitoring the electrical resistance. Elastic modulus, yield strength, ultimate tensile strength, ductility, and toughness were obtained by monotonic tensile test on the same samples. The Cu foil with higher toughness and ductility showed higher reliabilities in folding or bending fatigue. However, elastic modulus and yield strength did not show any relationship with folding and bending reliability. This is because the failures of Cu foil by folding or bending fatigue were closely related to the fracture energy of metal.

• 보존과학연구
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• s.21
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• pp.145-175
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• 2000

To examine the method for preservation of papers, 9 kinds of papers were purchased and pretreated for 6 months with various artificial conditions which were controlled as 3 temperature classes($20^{\circ}C$, $80^{\circ}C$, $-20^{\circ}C$&$20^{\circ}C$) and 4 humidity classes(40%, 60%, 80%, 100%).Whiteness, acidity and folding endurance were measured to examine the state of papers pretreated under each condition. From the resultexamining the state, all the papers were best condition at low temperature($20^{\circ}C$) and low humidity(40%) and damaged at high temperature($80^{\circ}C$) and high humidity(100%).The values of whiteness, acidity, and folding endurance were measure din relation with deterioration of papers. According to damage of papers caused by the chemical agent, papers became to be acidic, increased color difference and reduced the force of folding endurance. The effect of change of temperature($-20^{\circ}C$&$20^{\circ}C$) on degradation of papers was not well acquired. Because the period of investigation was not long enough to acquire the data. So the more studies are needed to find the cause of damage of papers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.1-5
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• 2013

Printing papers published in between 1950's and 1990's were treated with three methods such as distilled water washing, $CaCO_3$ solution washing and methyl cellulose solution coating for improving their conservational properties. Accelerated aging with $80^{\circ}C$ and 80% RH for 14 days was applied to the testing papers. Results showed that distilled water and $CaCO_3$ washing kept increased pH even after accelerated aging, but did not improve folding endurances for 1950's-60's papers. Methyl cellulose treatment did not increased pH of the old papers, but increased folding endurances remarkably for 1950's-60's papers even after accelerated aging. It suggests that methyl cellulose treatment after $CaCO_3$ washing should give improvements both in pH and folding endurance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.3
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• pp.37-42
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• 2010

The properties of paper are very susceptible to moisture content originated from relative humidity. This propensity of PVA impregnated paper was investigated in this study. Especially the hardening effect of borax treatment after PVA impregnation on the response of paper sample to the relative humidity was evaluated. When the moisture content was increased with the relative humidity, tensile stretch and tear resistance were increased while tensile strength and stiffness were decreased. A great increase in folding endurance of PVA impregnated paper sample was found at the higher relative humidity. The borax treatment could reduce the response of PVA impregated paper to the relative humidity.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.15-20
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• 2012

The effects of sulfur dioxide on paper were investigated since these sulfur compounds could cause damages on cellulose and organic materials in papers. For the reason, exposure ageing tests were performed on traditional Korean paper (Hanji) and two different types of modern paper (acid-free and acid paper) to determine the damage with regard to the optical as well as physicochemical properties according to the varying $SO_2$ concentration. As a result, optical properties were not changed while physical and chemical peoperties were remarkably changed with the exposure period. In the case of pH, $SO_2$ had little impact on the pH of the Hanji and acid-free paper while the pH of acid paper was remarkably decreased. The decrease of the folding endurance of the Hanji was relatively smaller than those of the acid-free and acid paper. The results prove Hanji was more resistant to $SO_2$ than the modern paper in terms of optical, physical and chemical properties. In addition, it was also suggested that $SO_2$ concentration should be kept below 0.01 ppm for the preservation of paper objects.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.9-14
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• 2012

Currently a variety of efforts to conserve and restore the injured the Annal of the Joseon Dynasty are continued and many studies about the aging pathway of the beeswax-treated volume have being progressed. In this study, two chambers were set up to assess the influence of VOCs(Volatile Organic Compounds) generated in process of beeswax deterioration. One chamber was closed and the other was continuously ventilated in order to remove the VOCs. In results, the acid compounds of beeswax-treated Hanjis aged in closed chamber was more than that aged in ventilated chamber. The folding endurance of beeswax-treated Hanjis aged in closed chamber was lower than that aged in ventilated chamber. Accumulated acid compounds of beeswax-treated Hanji in closed chamber may cause accelerated aging and strength decrease. In conclusion, accumulated acid compounds can accelerate the aging of beeswax-treated Hanji and cause the severe deterioration of inside of beeswax-treated volume. Therefore, to preserve more safely beeswax-treated volumes of the Annals of the Joseon Dynasty, it is essential that VOCs emitted from beeswax-treated volume are ventilated.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.3
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• pp.1-8
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• 2013

Hanji has been used mainly for preservation paper because of superior mechanical properties. However, it was not used in printing for inkjet and laser printer-printed letters. In this study, machine-made Hanji was prepared with five different contents of paper mulberry 20, 40, 60, 80 and 100% and managed by same pressure calendering. By increasing of paper mulberry contents, tearing index and folding endurance of machine-made Hanji increased because of increased fiber-to-fiber bonding. Printability property of machine-made Hanji improved by decreasing of paper mulberry contents. After 20 hours accelerated aging, the initial folding endurance of machine-made Hanji was reduced by approximately one-fourth degree. Between 40 and 100% contents of paper mulberry was showed similar levels about preservation property. The machine-made Hanji of paper mulberry 60% content was suitable for permanence and printability properties using preservation paper and printer-printed letters.