• Journal of Conservation Science
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• v.31 no.4
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• pp.457-476
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• 2015

This study is expected to present instructions and analysis of Modern Dancheong pigments by its physical characteristics. Search pigments currently used and experiments proper mixing ratio of Jangdanyuksaek(Incarnadine). Samples are made by based on presented a mixture ratio which is less exfoliation, cracks and color change. And put into accelerated weathering test and ultraviolet ray degradation test. As a result in case of Jidang($TiO_2$) Rutile type is superior in discoloration and durability. Rutile type makes color difference remarkably because of oil absorption difference while mixing with Jangdan. Water paints which are used as a alternative present yellowness which means water paints lack in durability. whiting should be taken carefully as it has high brightness after degradation.

• Journal of the Korean Applied Science and Technology
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• v.20 no.1
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• pp.8-19
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• 2003

Environmental friendly acrylics/urea high-solid paints (BEHCU) were prepared through the curing reaction of acrylics resin(BEHC) containing 70wt% of solids content and butylated urea curing agent. BEHC was synthesized by addition copolymerization of caprolactone acrylate(CLA), 2-hydroxypropyl methacrylate(2-HPMA), ethyl methacrylate, and n-butyl acrylate. The addition polymerization of these monomers, especially including flexible CLA monomer and 2-HPMA monomer with OH funtional group, under appropriate reaction conditions resulted in polymers with controlled glass transition temperature($T_g$) and crosslinking density. The molecular weight($M_w$) of these polymers(BEHCs) was 2940${\sim}$3240 and polydispersity ($M_w/M_n$) was in the range of 1.61${\sim}$1.72. The viscosity and the molecular weight of these acrylic resins increased with increasing $T_g$. The coated films were prepared using curing reaction between BEHC resin and butylated urea curing agent at 100$^{\circ}C$ for 30 minutes. Our experimental resulted showed that enhancement of the coating properties such as adhesion, flexibility, impact resistance, water resistance, and abrasion resistance could be expected through introducing CLA component in acrylic resin for the high-solid content acrylics/urea coatings.

• Journal of Adhesion and Interface
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• v.16 no.1
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• pp.15-21
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• 2015

In this study, rheological properties and flow dynamics in roll coating process of basecoat paints have been investigated for automotive precoated metal (PCM) sheet applications. Various rheological properties for basecoats with three colors (black, blue, and silver), such as shear viscosity data at room temperature and elastic/viscous moduli under thermal curing condition, have been measured using a rotational rheometer. It is found that the relative portion of function groups inside basecoats and their viscosity level have greatly affected the formation of crosslinked networks by thermal curing. Also, operability coating windows for basecoats have been established in three-roll coating process system by observing their flow instabilities such as ribbing and cascade. It is confirmed that rheological approaches applied in this study have been usefully applied to develop environmentally-friendly PCM coating technology and optimally control the coating operations for non-Newtonian PCM paints.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.400-409
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• 2016

In recent, shipping companies have made an enormous effort to improve the operation of vessel in various approaches, due to recession of shipping market and increasing competition among shipping companies. One of important parameters for improving the efficiency of vessel is the resistance performance that consist of friction and residual resistance. Especially, it is recognized that the friction resistance tends to be affected by conditions of vessel’s surface and occupies approximately 70~90% of the total resistance for slow speed ships. In general, the surface of vessel is covered with various type of paint to reduce fouling and corrosion. As time goes by, however, it is so hull roughness would be increased by fouling over the wetted surface that anti-fouling paints, such as CDP(Controlled Depletion Paint), Tin-Free SPC(Self Polishing Co-polymer) or Foul Release, are applied evenly on the hull surface. Nevertheless, these anti-fouling paints could not prevent fouling absolutely. A fundamental study on evaluating ship resistance performance variation due to hull roughness has been performed using a commercial software, Star-CCM+, which solves the continuity and Navier-Stokes equations for incompressible and viscous flow. The results of present simulation for plate are compared with some experimental data available and the effect of surface roughness to ship resistance performance is discussed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.39-49
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• 2021

The Korean Air-Force aircraft maintenance depot paints the exterior of various aircraft, including high-tech fighters. Aircraft exterior painting is a maintenance process for long-term life management by preventing damage to the aircraft surface due to corrosion. The de-painting process is essential to ensure the quality of aircraft exterior paints. However, because the Korean Air-Force's de-painting process is currently done with sanding or Plastic Media Blasting (PMB) method, it is exposed to harmful dust and harmful compounds and consumes a lot of manpower. This study compares the de-painting process currently applied by the ROK Air-Force and the more improved process of the US Air Force, and performs economic analysis for the introduction of advanced equipment. It aims to provide information that can determine the optimal time to introduce new facilities through Cost-Volume-Profit (CVP) analysis. As a result of the analysis, it was confirmed that the sanding method had the most economical efficiency up to 2 units per year, the PMB method from 3 to 21 units, and the laser method from 22 units or more. In addition, in a situation where the amount of de-painting work is expected to increase significantly due to the increase in fighters in future, BEP analysis was conducted on the expansion of the existing PMB method and the introduction of a new laser method. As a result of the analysis, it was confirmed that it is more economical to introduce the laser method when the amount of work exceeds the PMB work capacity(18 units per year). The paper would helpful to improve the productivity and quality of the Korean Air Force Aircraft maintenance depot through timely changes of facilities in the workplace in preparation for expansion.

• Land and Housing Review
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• v.13 no.4
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• pp.115-123
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• 2022

This study aims to introduce a temperature discoloration roof system and its cooling effect in the summer. Temperature discoloration paints can reverse their colors based on temperature changes. If these paints on the roof surface could color-shift between white in the summer and black in the winter, the indoor cooling and heating loads can be affected by the changes in reflection and absorption of solar radiation. Focusing on the summer period, the study analyzed the cooling effect of applying temperature discoloration paint that color-shifts from white to black on the roof surface of a small experimental building module and compared it to commonly used gray and green roof colors. Results of the experiment showed that the surface temperature of the roof with temperature discoloration paint was lower than the gray and green color roofs by a maximum of 10℃. Furthermore, the indoor temperature of the experimental module with the temperature discoloration roof was lower than the gray and green roofs by approximately 3℃. Findings of the study indicate that the application of temperature discoloration paint to the roof can reduce indoor cooling loads.

• Journal of Environmental Analysis, Health and Toxicology
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• v.21 no.4
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• pp.209-219
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• 2018

In the areas of RoHS, WEEE, ELV and REACH, reinforcement of environmental regulations against harmful substances is a global trend not only in EC but also in all over the world. In the fields of Korea's major export products such as material parts, electrical and electronic products and automobile parts, we are responding to these regulations consistently. To develop reference material for analyzing lead and cadmium in paints, the candidate materials were produced through the screening process which separated shapes and sizes. To secure the traceability of the candidate materials produced, the characteristics and uncertainties are estimated by ICP-AES analysis using the primary reference material. The short-term and long-term stabilities also are evaluated in parallel. In order to calculate the final certification value of the candidate material, the verification were carried out by the performance evaluation through the comparison among the KOLAS (Korea Laboratory Accreditation Scheme) laboratories, and the CRM was produced in accordance with ISO Guide 35. The certified values and uncertainties of Pb and Cd of the final paint standard, determined according to the joint analysis among laboratories, are Pb [($191.4{\pm}3.1$) mg/kg, ($944.1{\pm}5.6$) mg/kg] and Cd [($45.0{\pm}2.6$) mg/kg, ($225.5{\pm}3.5$) mg/kg]. These standard materials were developed to enhance the reliability of measurement analysis, including the validity and traceability of measurement results. Also it is expected that the CRM will be used as QCM (quality control material) for the product design and the process monitoring, so that regulation and management of hazardous heavy metals can be systematically implemented.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.593-604
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• 2021

In this study, a comparative test was conducted on a specially developed elastic waterproof paint and general water-based paint for the purpose of responding to cracks occurring on the outer wall of concrete structures and improving watertightness. Through the comparative experiment, it was confirmed that the watertightness could be improved by securing the crack shielding property, and it was also confirmed that about 10 times more crack responsiveness was secured compared to general water-based paint. In addition, it was confirmed that the adhesion performance of at least 1.3MPa and resistance to a water permeation pressure of 0.1MPa were possible, confirming that stability was secured from a waterproofing perspective.

• Journal of Conservation Science
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• v.30 no.2
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• pp.219-234
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• 2014

Fabrics, natural dyed fabrics, papers, natural dyed papers and paints were examined effects of colors and mechanical properties for materials of museum collections under anoxic treatment. Anoxic conditions using nitrogen and argon were oxygen concentration 0.01%, temperature($20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$), 50% RH and exposure time 30 days. Examined fabrics were raw silk fabric, UV irradiated raw silk fabric, degummed silk fabric, UV irradiated degummed silk fabric, cotton fabric, and UV irradiated cotton fabric. Natural dyed silk and cotton fabrics were dyed with fresh indigo, indigo, safflower, gromwell, madder sappanwood, amur cork tree, turmeric, gardenia, barberry root, pagoda tree flower, cochineal, lac, alnus japonica, gallnut, chestnut shell, and combination(indigo and safflower, indigo and amur cork tree, indigo and pagoda tree flower, indigo and sappanwood). Papers were Korean papers(mulberry paper, mulberry(70%) and rice straw(30%) mixed paper), Japanese paper(gampi paper), cotton paper, refined linen paper, cotton, linen & manila mixed fibre furnish, copy paper, news print, and alum sized mulberry paper. Natural dyed papers were dyed with indigo, sappanwood, madder, safflower, gardenia, amur cork tree, and pagoda tree flower. Paints were painted on alum-sized papers and silk fabrics using glue and pigments(azurite, malachite, cinnabar, vermilion, orpiment, gamboge, red lead, haematite, iron oxide red, indigo(lake), lac, cochineal, safflower, madder root lake, celadonite, smalt, ultramarine blue, lapis lazuli, prussian blue, kaolin, lead white, oyster-shell white, and clam-shell white). The color differences(${\Delta}E^*$) of all examined materials were below 1.5 or lowered than control samples after anoxic treatment. The variations of tenacity of yarns of fabrics and natural dyed fabrics after anoxic treatment were within that of standard silk and cotton fabrics. Gases(nitrogen and argon) and temperatures of anoxic treatment did not also affected color differences and variations of tenacity of materials.

• Journal of the korean society of oceanography
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• v.33 no.3
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• pp.64-70
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• 1998

Forty sediment samples from Kyeonggi Bay, Korea were analyzed for butyltins, including tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) to determine their distribution and source in this area. Total butyltin concentrations in Kyeonggi Bay sediments ranged from 0.8 to 297 ng/g dry wt. with a mean value of 38 ng/g. The highest butyltin concentration was found in the innermost site in Incheon Harbor basin. The mouth of Han River had higher butyltin levels in sediments compared to open ocean. Butyltin levels correlated well with organic carbon content of sediment, but the major factor was the distance from the source area where antifouling paints were used for vessels and marine structures. Butyltin concentrations in the study area were lower than those reported for bays in other parts of the world. Considering the high toxic potential and sediment/water partition coefficient of TBT, further studies are needed to assess its biological effect in the marine ecosystem of Kyeonggi Bay.