• Journal of Conservation Science
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• v.32 no.4
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• pp.501-510
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• 2016

In this study, we investigated the degradation of adhesives when exposed to ultraviolet light irradiation using samples of lacquer (L), treated lacquer (TL), lacquer mixed with glue (LG), and urushiol mixed with glue (UG). Four types of film specimens were collected under the ultraviolet exposure time, and gloss test, tensile shear strength test, scanning electron microscope analysis, and infrared spectroscopic analysis were conducted for the specimens. LG and UG showed lowering rate of gloss is somewhat later than L. Also, it was observed that with increasing exposure time to ultraviolet irradiation, the surface of L began to show spherical pits and cracks when the polysaccharide layers started to be exposed, whereas the surfaces of LG and UG remained smooth. The Infrared spectra of L and TL showed that the intensity of the overall peak decreased with increasing ultraviolet irradiation time. There was no change in the peak intensity of LG, but for UG, the peaks at $3013cm^{-1}$, $1593cm^{-1}$ and so on disappeared and the overall intensity declined. The tensile shear strength of LG and UG was maintained or increased as compared to the initial test, whereas the tensile shear strength of L decreased sharply after 600 h. LG and UG exhibited fewer changes as a result of high temperature and humidity conditions, and they retained their strength under UV exposure. These results indicate that LG and UG are more durable than L when subjected to environmental change.

• Journal of the Korean Wood Science and Technology
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• v.29 no.1
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• pp.31-42
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• 2001

In this study, we obtained fundamental data about Korean raw lacquer's physical and chemical properties to produce high quality lacquer. The tested raw lacquers were obtained from Won-ju in Korea, Shanxishang, Guizhoushang, Anhuishang in China. The drying time of refining lacquers, tensile strengths of dried films and uniformity of films are measured. The refined lacquers were prepared by experimentally scaled refining equipment. Films of lacquer were applied on glasses by film applicator. This films were tested by universal strength test machine. The films were pictured by scanning electron microscopy and confocal microscopy to define the uniformity of them. The refining method were not different among three different kind of raw lacquers which were different their collecting time and places. But the viscosity of them were quite different. When black refined lacquer is made with iron powder, the adding time of iron powder is critical to control the viscosity of it. The refining times, viscosity and tensile strength of refined lacquers were not depended the method of refining condition but the place of collecting of raw lacquer.

• Journal of the Korean Wood Science and Technology
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• v.31 no.4
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• pp.81-90
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• 2003

In this study, we investigated the weathering properties of Korean Rhus lacquers containing tung oil and their potential use as exterior coatings. The finished lacquers were prepared with a raw Korean Rhus lacquer or refined Korean Rhus lacquer content of 10, 20, 30 and 40 wt.% (corresponding to ratios of 10/90, 20/80, 30/70 and 40/60 by weight of Korean Rhus lacquer/tung oil, respectively). The curing temperature of the prepared lacquer increased with increasing the content of the raw Korean Rhus lacquer. This increased curing temperature is related to higher proportion of hydroxyl groups in the prepared lacquer, due to the content of the raw Korean Rhus lacquer. In accelerated weathering testing, the changes in the gloss and contact angle of the prepared lacquers showed a similar trend to that of traditional exterior oil stain. In addition, the prepared lacquers containing tung oil showed greater discoloration than traditional exterior oil stain. However, the discoloration of the prepared lacquer with a raw Korean Rhus lacquer content of 40 wt.%, and that of the prepared lacquer with refined Korean Rhus lacquer contents of 30 wt.% and 40 wt.%, showed a similar trend to that of traditional exterior oil stain. Consequentially, these prepared lacquers showed a potential for being used as exterior coatings.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.405-410
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• 2019

This study is an primary analysis on convergence of porcelain lacquer painting art which is composed of porcelain art and raw lacquer technic. As a part of ceramic art, this study suggest 3 ways of porcelain lacquer decoration with understanding of its history and contemporary status. Lacquer technic gives stability for surface paintings and it also has various media to express its beauty. Porcelain lacquer decoration art contains artistic value and pragmatic purpose for daily life usage. These days, due to unavailability for mass production, it tends to be tried for art work purposes. However this artistic technic and value can be applied to porcelain goods, so that it will raise aesthetic pleasure and cultural diversity.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.105-112
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• 2008

Grading of the urushi lacquer is quite difficult because of large variations depending on origin, growing conditions, time acquisition, storage conditions. It is urgently required to establish a grading system of urushi lacquer by combining traditional method with scientific methods. Traditional grading of urushi lacquer was done by visual inspection of 10 experts who are working on urushi lacquer industry. Common aspects of the experts were color, odor, viscosity, spread properties on Hanji, color and drying properties on glass based the traditional grading system. In addition, rubbing on Hannj and heating with alcohol lamp was also used to grade urushi lacquer. The grading results of 10 experts showed that chinese urushi lacquer (E) of 7.03, japanese urushi lacquer (C) of 6.84, domestic urushi lacquer of (A) of 6.41 and another chinese urushi lacquer (D) of 5.27, and domestic urushi lacquer (B) of 2.50 in descending order. The degree of spread on Hanji was not consistent among 10 experts. These results indicated that the traditional grading system was pretty much personal and required of developing more objective method based on scientific background.

• Journal of Conservation Science
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• v.37 no.3
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• pp.302-311
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• 2021

This study uses traditional lacquer techniques to coat the metal surface and evaluates its physical properties to check the applicability of the lacquer coating. For this purpose, a total of six specimens were produced by setting the variation conditions for the number of times (1, 2, 3) and the heating temperature (120℃, 150℃) using SS275 metal(60*60 mm) and 'Wonju lacquer'. For analysis, chromaticity measurements, contact angle/surface energy measurements, Chemical Resistance, and cross-cut tests were used. The analysis showed that the corrosivity was improved and the adhesion of lacquer to the metal surface was excellent. There was no significant change in contact angle/surface energy. Also, there was no significant difference in color. Through this study, it was confirmed that lacquer on metal surfaces improves waterproofing and has a anticorrosion effect. We could also check the proper number of lacquer and heating temperature. Additional physical characteristics such as hardness and wear rate should be studied. It is also necessary to study how lacquer can be painted with a certain thickness.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.40-46
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• 1998

For the comparison of the urushiol composition and biological acitivity between the fresh sap and fire distilled sap of lacquer tree(Rhus vernicifera), we analysed the urushiol composition by HPLC and EI-MS, and investigated the antioxidative , antimicrobial and anticancer acitivities according to solvent fractionations. There was no difference in the urushiol composition between fresh and fire distilled saps of lacquer tree. The hexane frqctionsof two saps showed a strong DPPH radical scaverging activity (RC50 : 7.0-7.5$\mu\textrm{g}$). They also showed a strong antifungal activity onthe spore germination of Cladosporium herbarum(MIC : 8$\mu\textrm{g}$/ml), whereas they have no or low activity against the bacteria(BAcillus subtilis , Escherichia coli). In addition , hexane and butanol fractions of two saps showed a strong inhibitory activity against cultured tumour cell lines (GI50 : 0.35, 12.29$\mu\textrm{g}$/ml) in vitro. These results confirm that the fresh sap and fire distilled sap might have the similar urushiol compositions and biological activities.

• Journal of Adhesion and Interface
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• v.12 no.4
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• pp.111-116
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• 2011

The characteristics of natural resin, sap of the lacquer tree were examined as an adhesive for the ceramic conservation since it has such outstanding properties like corrosion resistance against acid and alkali, heat-resistance, waterproof, antiseptic and protection against insects. In order to utilize raw lacquer as an adhesive not under the hardening conditions of lacquer like high humidity (RH 75 to 85%) and high temperature (120 to $170^{\circ}C$), but under normal condition, isinglass and animal glue were added to raw lacquer at certain ratio. In addition, the viscosity and the drying time were measured and their possibilities of application were also investigated through measurement of tensile and adhesive strength. As a result of experiment, it was possible to dry at room temperature and RH $50{\pm}5%$ to mix with raw lacquer and glue, and the drying time of sample with animal glue was faster than that of isinglass. Furthermore, the adhesion of sample with glue was increased more than raw lacquer. It seems to be possible to use the environmental friendly traditional adhesive for the ceramic conservation and restoration, if there are studies or examinations of safety of applications on objects and weathering resistance.

• Journal of the Korean Wood Science and Technology
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• v.29 no.1
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• pp.43-51
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• 2001

When percentages of the component of raw lacquer were changed by adding each components that is urushiol, polysaccharide and glycoprotein, the physical properties of refined lacquer were changed and the period of refining also were changed. When polysaccharide component extracted from raw lacquer was added in raw lacquer, the period of refining was shortened about 1/3 times and this refined lacquer film was dried faster than the refined lacquer which was not added any other components. When urushiol extracted from raw lacquer was added in raw lacquer, the transparency of dried film was improved. A case of Guizhoushang was improved of the tensile strength of dried film. When both urushiol and polysaccharide were added in raw lacquer, the drying time of refined lacquer was shortened and the tensile strength of them also was improved.

• 보존과학연구
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• s.32
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• pp.37-52
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• 2011

This study investigates the hardening characteristics of the mixture lacquer and glue at room temperature. Diverse samples were made from manufacturing of glue to the adding ratio in sap of the lacquer tree. After the examination of moisture content of samples, it has been seen that there is no relation with glue's kinds or adding ratio, but only with contain level of moisture. The samples made with film shape in order to examine the drying time. Samples with isinglass needed for over three days and had smooth surface. However, samples mixed with animal glue dried within a day and had ripples on the surface because of fast drying rate. In addition, the samples with isinglass had slow change of colour in early step of drying and no colour difference after completely drying although it had significant changes to black oxide as soon as contact with air. In structural analysis with FT-IR showed that the carbonyl bond increased in the samples of mixed with glue, compared to raw lacquer and treated lacquer.