• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.330-339
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• 2009

The material properties of Cedar (Cryptomeria japonica) were evaluated according to heat treatment conditions. The special focus was made on the color control of cedar wood by heat treatment. The difference of color between sapwood and heartwood could be reduced by heat treatment at a temperature above $170^{\circ}C$. Long heating time was more effective in reducing the difference. The Equilibrium Moisture Content (EMC) of heat-treated wood was as low as 50 percent. The result obviously indicates that heat-treated wood is more dimensionally stable in the change of moisture condition than the control. The heat-treated wood was also effective in increasing the durability against wood rotting fungi. However, more study is required to develop heat treatment as an environmentally-friendly technology for wood preservation without chemical. The mechanical properties of heat-treated wood showed relatively higher performance than the control in general. Meanwhile the dramatic decrease in impact bending stress due to the loss of ductility may limit uses of heat-treated wood in certain cases. There were no significant changes in microscopic structure which may cause changes in mechanical properties. Further study on the chemical analysis of heat-treated wood is needed to scrutinize the causes of changes of material properties.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.221-230
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• 2018

The purpose of this study was to evaluate the effect of several chemical treatments to prevent photodegradation of wood veneer by external UV (Ultraviolet) light. Of woods, walnut veneer is selected as a raw material for this study since it is known as a luxurious wood with dark color giving an esthetic effect. Alcohol-benzene, hydrogen peroxide ($H_2O_2$) and sodium hypochlorite (NaClO) solution were used for investigate the effect on color stabilization. Despite the removal of the extractive compounds, which is known as a discoloration component, a significant color change of walnut wood veneer was observed. Meanwhile, the veneers treated by 20 and 30% $H_2O_2$ solution at $75^{\circ}C$ for 1 h also showed the no positive effect of color stability exposed to UV light although they have a bleaching effect on wood veneer. Besides, it was difficult to maintain the original color of walnut veneer due to the elution of the extractive compounds. On the other hands, the veneer treated by NaClO solution indicated the good performance on color stability despite of the intensive UV light test. However, when the concentration exceeds 3%, surface roughness and fiber damage occurred simultaneously. Therefore, the walnut species should be treated with proper concentration when sodium hypochlorite is applied to the veneer.

• Journal of the Korea Furniture Society
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• v.24 no.1
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• pp.79-87
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• 2013

The objective of this study was to increase the utilizability of domestic thinning and small diameter wood as applying in pattern design which can be applied in interior decoration, wood craft and wood furniture, and in developing the designs of furniture and household items. Then we investigated the physical and mechanical characteristics of Acer mono wood by pressurization and heat treatment. Color change is clear, and the wood density is increased with increasing pressing rate. The compressive and bending strengths are decreased as heating time is increased after pressing. However, shrinkage is improved after pressing and heating.

• Journal of the Korea Furniture Society
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• v.25 no.2
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• pp.96-103
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• 2014

The objective of this study was to increase the utilizability of domestic thinning and small diameter wood as applying in pattern design which can be used in interior decoration, wood craft and wood furniture, and in developing the designs of furniture and household items. We investigated the physical and mechanical characteristics of Betula platyphylla Wood by pressurization and heat treatment. Color change is clear, and the wood density is increased with increasing pressing rate. The compressive strength, modulus of rupture and modulus of elasticity in bending strength are decreased as heating time is increased after pressing. However, shrinkage is improved after pressing and heating.

• Journal of the Korea Furniture Society
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• v.23 no.2
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• pp.152-162
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• 2012

The color changing of the wood surface was tested by accelerated weathering test that can simulate the outdoor condition with short period. In early parts of accelerated weathering test, weight and volume of specimen all were increased due to the moisture evaporation by its high temperature and illumination level, but weight and volume of specimen all were decreased from middle parts to last. However, significancy showed between control group and accelerated weathering test group in terms of weight and volume. According to the results of color-difference meter, in the early parts of the accelerated weathering test lightness, redness and yellowness all showed a clear increasing or decreasing trend. However, after three weeks all values were almost never change. Until the early parts of the test, lightness was decreased and there was not a considerable change after three weeks in the test. Redness showed a some change in early parts of the test, but this also showed not great change after middle parts of the test as like lightness. Yellowness also showed same pattern. These results could be verified through the visual inspection. As like weight and volume, significancy showed between control group and accelerated weathering test group in terms of color-difference test. In all accelerated weathering test group, color-differences of after test was lower than that of before test. To correctly analyze this cause, more additional research will be need on each of temperature, humidity and illumination factors.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.438-445
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• 2015

Among several thermal wood modification methods German oil heating technology was applied to Korean pine specimens by heat treatment at $180^{\circ}C$ and $200^{\circ}C$. In addition the matched specimens were heat-treated by Thermowood method. The heat-treated specimens were planed and their colors were measured with a colorimeter at 1 mm and 4 mm below the surfaces. The average lightness index (L*) of Oil-180 specimens was the largest followed by Oil-200 and Tmo-200 specimens. The average redness indexes (a*) of all specimens were increased by heat treatment, while the average yellowness indexes (b*) were variable. The average color differences (${\Delta}E*$) of Oil-200 and Tmo-200 specimens were above 30.0, while that of Oil-180 specimens was only 18.4. It can be concluded that the colors of the heat-teated specimens were uniformly changed because their average color difference indexes (${\Delta}E*$) between the inner layers were below 6.0.

• Journal of the Korean Wood Science and Technology
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• v.42 no.1
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• pp.13-19
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• 2014

Three heat-treatment schedules were applied to $90{\times}90mm$ dimension square lumber of Pinus koraiensis, one of major domestic species, and their colors and physical properties were investigated for obtaining an optimum schedule. Each square lumber was heat-treated three times. The temperatures of $170^{\circ}C$ and $190^{\circ}C$, and the time of 9 hours and 13 hours were used for the first heat-treatment. The schedule of $190^{\circ}C$ and 7 hours were used for the next two heat-treatments. The averages of brightness $L^*$ decreased linearly as the heat-treatment repeated and its standard deviations also decreased slightly. While the averages of color difference ${\Delta}E^*$ increased linearly as the heat-treatment repeated and its standard deviations also increased slightly. The average compressive strength of the heat-treated specimen was higher than that of the control by 9%, which deviates from previous reports. ASE and WPG of the heat-treated specimens were measured to confirm that heat-treatment improved dimensional stability significantly.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.457-460
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• 2006

There are many kind of materials decorating outward of building such as paint, tile, brick, wood, stone and so on. But it has been pointed out some problems because of the industrial pollutions and wastes. Color concrete is a method of expressing out surface of exposed concrete. Generally, color concrete is manufactured by adding pigment to concrete. In this paper we used cement paste as a preparation step to apply to concrete. Pigment was added to white cement for easy observance of color difference. And color change was measured by color reader. Finally, we can predict color difference according to amount of pigment. Also, we investigate the color concrete technology for Art type using developed color concrete.

• Journal of the Korea Fashion and Costume Design Association
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• v.9 no.2
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• pp.85-92
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• 2007

This study focused on bean-juice treatment method which have dyeing property to indigo, yellow soil, sappan wood, cochineal and also on the possibility of applying to mordanting. This is different from the active mordanting using chemicals. Natural mordants with development of dyeing are not harmful, also are the medicines for disease. Limestone and ash neutralize the acidic soil. bean-juice protein adhere to cellulose surface and change the physical properties of protein so that coloring of dye is better than before and film non-soluble in water is made. Therefore the color made from bean-juice process lasts after washing. This study try to show one of the ways to improve the current method using the heavy metal which can have bad effects for environment and human being. Bean-juice(raw bean, heated bean) treatment method can be the way to fix the natural dyeing problem of bad dyeing. Bean-juice had been treated under various condition with pre-treatment, post-treatment and raw bean, heated bean. Following results are obtained in this study. In the case of Indigo dyeing, pre-treatment of heated bean shows the biggest difference of color. In the case of yellow soil dyeing, pre-treatment of raw bean-juice shows the biggest gap of color. Pre-treatment of heated bean in sappan wood dyeing case and post-treatment of raw bean show bigger color difference than pre-treatment of raw bean. In cochineal dyeing, raw bean pre-treatment shows the biggest color difference.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.1
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• pp.24-30
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• 2012

This study was carried out in order to analyze a repletion possibility about color change of base paper after elevated heat exposure when wooden fillers were added. Fillers may reduce production cost because its price is usually inexpensive than pulp with higher bulkiness. Wooden fillers have lower density than inorganic fillers, so they may increase bulk more than inorganic fillers. Never the less wooden fillers have disadvantage of yellow color by heat exposure, so the addition level should be carefully controlled. Brightness and whiteness changes after elevated heat exposure depending on coating weight were analyzed. With wooden fillers addition, breaking length and surface strength decreased but bulkiness increased. As the exposure time of elevated heat increased the coating paper with wooden fillers addition had higher brightness and whiteness values than those of inorganic fillers.