• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.23-35
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• 2004

The goal of study was to investigate the influence of the acrylated urethane oligomer on mechanical properties, the chemical resistance and thermal resistance of the UV curable urethane acrylate coatings for fancy veneer overlayed plywood flooring. The pencil hardness and abrasion resistance of the coated fancy veneer overlayed plywood floorings increased with increasing the acrylate functionality of the acrylated urethane oligomer. In the case of the UV cured film containing hexa-functional acrylated aliphatic urethane oligomer, high discoloration of the coated fancy veneer overlayed plywood flooring was observed near the cracks at the beginning of the chemical treatment. In this study, it was found that the degradation of the UV cured film caused by an alkaline reagent was higher than that of the UV cured film caused by an acidic treatment.

• Journal of the Korean Wood Science and Technology
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• v.36 no.2
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• pp.46-55
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• 2008

This study assesses the formaldehyde and TVOC emissions from bio-composites with attached fancy veneer manufactured using wood flour and polypropylene (PP) measured using the Field and Laboratory Emission Cell (FLEC) method and 20 L small chamber method. To determine and compare the effects of the adhesive, samples were prepared with different manufacturing methods. In the FLEC result, the formaldehyde emission level of the bio-composites with attached veneer by hot-press was the lowest than pure bio-composite and bio-composite attached veneer using adhesive. The TVOC emission levels are similar to the formaldehyde emission. The TVOC emission level is very low in all of the samples except fancy veneer that is attached with bio-composites using adhesive. The TVOC emission varies depending on how attaching fancy veneer. The results of the 20 L small chamber method were very similar to those obtained with the FLEC, but the correlation was not perfect. However, the FLEC method requires a shorter time than the 20 L small chamber method to measure the formaldehyde and TVOC emissions. The internal bonding strength exceeded the minimum value of $0.4N/mm^2$ specified by the KS standard. All of the bio-composites with attached veneer satisfied the KS standard.

• Journal of the Korean Wood Science and Technology
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• v.38 no.5
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• pp.385-390
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• 2010

This study was carried out to manufacture very thin natural elm veneer overlaid charcoal board for enhancing aesthetic value of charcoal board for the indoor application, and to use the advantageous properties of the charcoal as a building material for solving the sick house problem. The thin elm veneer had 26.9% opening ratio. The experiment results showed that the spreading area and the nonvolatile content of adhesive did not affect the gas adsoprtion of fancy veneer overlaid charcoal board. The natural thin elm veneer overlaid charcoal board enhanced not only the aesthetic beauty but also showed the same gas adsorption by the charcoal board.

• Journal of the Korean Wood Science and Technology
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• v.39 no.5
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• pp.451-458
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• 2011

Adhesives derived from renewable resources allow wood panel producers to make lower cost alternatives to formaldehyde-based adhesive resins. Among them, adhesive components extracted from industrial by-products or wastes are the most important research fields in the efficient utilization of waste and cost reduction. In our study, the rapeseed flour, which is a by product from the production of biodiesel extracted from rapeseed, was introduced to develop alternative adhesives for the production of wood flooring. The rapeseed flour was hydrolyzed with 1% sodium hydroxide solution and PF prepolymers were prepared with 3-molar ratios, 1.8, 2.1 and 2.4. The linear fracture mechanics was introduced to evaluate the glue bond quality in wood flooring composed of fancy-veneered and plywood, and the formaldehyde emission and adhesive penetration were also investigated. The formaldehyde emissions of wood flooring met the requirement of the standard of $SE_0$ specified in the KS standard. The rapeseed flour adhesive penetrated sufficiently into the vessel elements and lumens in fancy veneer and plywood and gave strong bond quality to the wood flooring. The fracture mechanics was introduced to evaluate the adhesive joint between fancy veneer and plywood. The critical stress intensity factor ($K_{IC}$) of boliva overlayed wood flooring was increased with increasing molar ratio and this was the same tendency in oak overlayed wood flooring. From the results, the formulated adhesives were efficiently used to bond fancy veneer onto the plywood to make wood flooring and showed a potential to be used as a component of environmentally friendly adhesive resin systems for production of flooring.

• Journal of the Korea Furniture Society
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• v.18 no.1
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• pp.13-19
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• 2007

The influences of coating on oak veneer overlaid Medium Density Fiberboard (MDF) were evaluated. The hardness of 9mm-MDF by hardness test were increased about 28% with coating on MDF and the more increased hardness of 31% with oak veneer overlaid MDF. The hardness of veneer overlaid MDF increased with increment of the veneer thickness and that of overlaid MDF showed the higher hardness compared to non-overlaid MDF. The optimum moisture content in terms of the hardness of panels MDF was in the range of 7% to 10% and the hardness was decreased with increasing of the moisture content. Any cracks were not overlaid coated on the MDF but the cracks were observed on the overlaid MDF after Soak under Vacuum Dry 10-cycle. The thicker veneer-overlaid MDF showed more cracks.

• Journal of the Korean Wood Science and Technology
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• v.33 no.4 s.132
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• pp.23-29
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• 2005

The fancy veneer flooring board is high value-added wooden material. The classification of the flooring boards by the observation with the naked eye causes color difference among fancy veneers. It turned out that this inaccuracy of color difference among fancy veneers increased in case of the identification by metamerism or the flooring construction. Therefore, this study was performed to classify fancy veneers produced from 3 species such as Tilia sp., Betula sp., and Acer sp. which were identified with the naked eye by Light and Dark grade, by using CIELAB. In addition, each specie's threshold on CIERGB was investigated and a range of hue, saturation and intensity by an application of HSI color model were studied. Intensity of the HIS color model could be the best value to be used when color, saturation and intensity of the HSI color model were used for the classification of the flooring board's color. In addition, it seemed that color range of all three criteria lied between $45^{\circ}$ and $55^{\circ}$. In the case of identification by threshold of RGB element, considering only specific color element value is unlikely to lead to accurate classification of fancy veneers of flooring board.

• Journal of the Korea Furniture Society
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• v.21 no.4
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• pp.284-292
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• 2010

This research was carried out to examine the properties of fancy cherry veneer overlaid on the PF resin bonded Meranti plywood floor, which 2.5% green tea leaf powder was applied in the UV varnishes and the adhesives for scavenging the volatile organic compounds. The results were as follows: 1. The various properties of the treated samples, such as density, moisture content, thickness swelling, bending strength(MOR), adhesion shear strength, surface abrasion, curling, cyclic delamination test with boiling water, boiling property, cold-resistance and heat resistance, acid resistance and alkali resistance, and anti-contamination property showed no significant difference between the properties of the control samples. 2.5% green tea leaf powder treated floor gave a little better results than the control for surface scratch test. 2. In case of QUV and weathering test, no difference between the treated sample and control was found. 3. The floor was discolored by adding 10% green tea leaf powder to UV coating, and the floor was also discolored to light green during by the soaking test. The color of floor was not changed up to 5% addition level.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.58-66
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• 2007

The objective of this research was to develop environment-friendly adhesives for face fancy veneer bonding of engineered flooring. Urea-formaldehyde (UF)-tannin and melamine-formaldehyde (MF)/PVAc hybrid resin were used to replace UF resin in the formaldehyde-based resin system in order to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. Wattle tannin powder (5 wt%) was added to UF resin and PVAc (30 wt%) to MF resin. These adhesive systems showed better bonding than commercial UF resin with a similar level of wood penetration. The initial adhesion strength was sufficient to be maintained within the optimum initial tack range. The standard formaldehyde emission test (desiccator method) and VOC analyzer were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with commercial UF resin, UF-tannin and MF/PVAc hybrid resin. By desiccator method, the formaldehyde emission level of UF resin showed the highest but was reduced by replacing with UF-tannin and MF/PVAc hybrid resin. MF/PVAc hybrid satisfied the $E_1$ grade (below $1.5mg/{\ell}$). VOC emission results by VOC analyzer were similar with the formaldehyde emission results. TVOC emission was in the following order: UF > UF-tannin > MF/PVAc hybrid resin.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.388-396
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• 2009

In our study, the potential of okara as an ingredient of new bio-based adhesives was investigated for the production of fancy-veneered flooring boards. Okara was hydrolyzed by 1% sulfuric acid solution (AC) and 1% sodium hydroxide solution (AK). Phenol formaldehyde (PF) prepolymers were prepared as a cross-linker of okara hydrolyzates. Then, okara-based adhesive resins were formulated with 35% AC, 35% AK and 30% PF prepolymer on solid content basis. The adhesive resins were applied on high-density fiberboards (HDF) with the spread rate of $300g/m^2$. After that, oak fancy veneers are covered on the HDF, and then pressed with the pressure of $7kg/m^2$ at $120^{\circ}C$. The experimental variables were three mole ratios of formaldehyde to phenol (1.8, 2.1, 2.4), three assembly time (0, 10, 20 min), and two press time (90 sec, 120 sec), respectively. The fancy-veneered high-density fiberboards were tested by dry tensile strength, glueline failure by wetting and formaldehyde emission. Tensile strength of the boards exceeded the requirement of KS standard. The formaldehyde emissions were approached at the E0 level specified in KS standard. Based on these results, okara can be used as an ingredient of environmentally friendly adhesive resin systems for the production of flooring boards.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.49-58
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• 2008

This research was carried out to use green tea leaves powder for scavenging effects of volatile organic compounds on the UV varnishes and adhesives of fancy cherry veneer overlaid on the PF resin bonded Meranti plywood. The results are as follows: 1) Green tea leaves contained 9.85% of polyphenol compounds. 2) FT-IR results showed green tea leaves had effects to react with benzaldehyde and ethyl hexyl alcohol to form a chemical bond. 3) 2.5% of green tea leaves powder content was proper for scavenging effect on the UV varnishes and adhesives of fancy veneer overlaid on the PF resin bonded plywood 4) 20 liters small chamber test indicated excellent emission speed results such as $0.089mg/m^2hr$ of TVOC and $0.001mg/m^2hr$ of HCHO (on 7th day), as compared with standard (less than $0.1mg/m^2hr$ of TVOC and $0.015mg/m^2hr$ of HCHO emission are the excellent grade).