• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.92-97
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• 1998

Four urea-formaldehyde (UF) resins were synthesized as a particleboard (PB) binder with the four different initial formaldehyde/urea mole ratio and the final mole ratio of 1.15. The UF resins were characterized according to the standard method of resin adhesive analysis. PBs were manufactured using liquid UF resins at 5 minutes press time and 6% resin solids levels on an ovendry particle weight basis. A total of 20 PBs was fabricated for 5 panel replication per UF resin types. The panels were tested for physical strength properties per the procedure ASTM D 1037. The formaldehyde emission levels from the PBs bonded with the UF resins were tested according to 2-hour desiccator test method ASTM D 5582. There were no significant differences among UF resin types for internal bond strength of PBs. But there were significant differences among UF resin types for formaldehyde emission level of PBs. The results showed that the formaldehyde emission level was influenced by the UF resin types without reducing the adhesive performance.

• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.29-41
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• 2006

This study was to investigate the effect of adding additive as tannin, rice husk and charcoal, for reducing the formaldehyde emission level, on the adhesion properties of urea-formaldehyde (UF) resin for particleboard. We controlled the hot-pressing time, temperature and pressure to determine the bonding strength and formaldehyde emission. Blends of various UF resin/additives (tannin, rice husk and charcoal) compositions were prepared. To determine and compare the effect of additives (tannin, rice husk and charcoal) content, 0, 5, 10 and 15%, by weight of UF resin, were used. $NH_4Cl$ as hardener added. To determine the level of formaldehyde emission, we used the desiccator, perforator and 20 L-small chamber method. The formaldehyde emission level decreased with increased additions of additive (except rice husk). Also, increased hot-pressing time decreased formaldehyde emission level. At a charcoal replacement ratio of only 15%, the formaldehyde emission level is under F ✩ ✩ ✩ ✩ grade (emit < $0.3mg/{\ell}$). Curing of the high tannin additive content in this adhesive system indicated that the bonding strength increased. But, in the case of rice husk and charcoal, the bonding strength was much lower due to the inorganic substance. Furthermore, rice husk was poor in bonding strength as well as formaldehyde emission than tannin and charcoal.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.204-207
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• 2009

The purpose of this study was to evaluation of impact factors, which are temperature and relative humidity on formaldehyde emission from MDF(Medium Density Fiberboard). The test was carried out at 4 specimens that were different of temperature and humidity by using small chamber system. Formaldehyde was sampled and analyzed by HPLC. The results of this study were as follows; 1) When the temperature increased from 25 to $35^{\circ}C$ at 50%, the emission rate of formaldehyde increased 1.0-1.6 times. 2) When the RH increased from 50% to 80% at $25^{\circ}C$, the emission rate of formaldehyde decreased 0.6 times. 3) The enhancement effect of temperature on Formaldehyde under RH of 50% was more significant than under RH of 80%.

• Journal of the Korean Applied Science and Technology
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• v.26 no.1
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• pp.18-23
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• 2009

Curing behavior and structural property of an inorganic compound added urea-formaldehyde(UF) and urea-melamine-formaldehyde(UMF) were studied. In addition, tensile strength and formaldehyde emission of plywoods made of those resin binders were studied. Curing temperature and structure were not changed, but tensile strengths of plywoods manufactured both with a UF resin and a UMF resin were decreased slightly as increased amount of inorganic compound. Formaldehyde emissions from plywoods were reduced as increased amount of inorganic compound. Wheat flour as an extender was helped to reduce of formaldehyde emission. From the result of this study it might be estimated that using appropriate amount of inorganic compound and proper resin system can be strengthened bond strength and reduced formaldehyde emission.

• Journal of Power System Engineering
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• v.3 no.2
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• pp.20-25
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• 1999

Experiments were carried out to investigate the characteristics of formaldehyde emission from the small gasoline engine and its reduction technologies. Catalytic converters used are Pt/Rh, Pd/Rh, Pd/Pt, $62cell/cm^2$ monolith type. The measurement of formaldehyde was conducted by using the method of DNPH-GC. From the experimental results, formaldehyde emission increased in a lean mixture due to incomplete combustion of the hydrocarbons. The order of catalytic activity of formaldehyde oxidation was Pt/Rh > Pd/Rh > Pd/Pt. As the distance from the exhaust manifold to the inlet of the catalyst became far, in spite of lower catalyst temperature, formaldehyde concentration decreased because of the adsorption of formaldehyde.

• Journal of the Korean Wood Science and Technology
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• v.33 no.2 s.130
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• pp.29-39
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• 2005

Formaldehyde emissions from wood-based panels bonded with pine and wattle tannin-based adhesives, urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), and co-polycondensed resin of urea-melamine-formaldehyde (UMF) were measured by the Japanese standard method using a desiccator (JIS A 1460) and the EN 120 (European Committee For Standardization, 1991) method using the perforator value. In formaldehyde emission, all particleboards made using the wattle tannin-based adhesive with three different hardeners, paraformaldehyde, hexamethylenetetramine, and tris(hydroxyl)nitromethan (TN), satisfied the requirements of grade $E_1$. But only those made using the pine tannin-based adhesive with the hexamine as hardener met the grade $E_1$ requirements. Hexamine was effective in reducing formaldehyde emission in tannin-based adhesives when used as the hardener. While the UF resin showed a desiccator value of $7.1mg/{\ell}$ and a perforator value of 12.1 mg/100 g, the MF resin exhibited a desiccator value of $0.6mg/{\ell}$ and a perforator value of 2.9 mg/100 g. According to the Japanese Industrial Standard and the European Standard, the formaldehyde emission level of the MDF panels made with UF resin in this study came under grade $E_2$. The formaldehyde emission level was dramatically reduced by the addition of MF resin. The desiccator and perforator methods produced proportionally equivalent results. Gas chromatography, a more sensitive and advanced method, was also used. The samples for gas chromatography were gathered during the experiment involving the perforator method. The formaldehyde contents measured by gas chromatography were directly proportional to the perforator values.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.165-171
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• 2002

This study was to investigate the adhesion properties of fancy veneer and base panels and formaldehyde emission of wood-based floorings bonded with urea-melamine formaldehyde adhesives. We focused on stoichiometric mole ratio of reactive functional groups. The urea-melamine formaldehyde adhesives were made at twelve different formaldehyde/urea-melamine mole ratios. The interlaminated shear strength and formaldehyde emission of wood-based floorings bonded with selected adhesive among these adhesives were examined. The results showed that the bonding properties were high and the formaldehyde emission was low as the adhesive consisted of stoichiometric mole ratio of formaldehyde/urea-melamine. Interlaminated shear strengths of HDF(High Density Fiberboard) flooring were over 14 kgf/cm² at all mole ratios. At the mole ratio of 1.0, HDF flooring showed low value of formaldehyde emission of 953 mg/L. Interlaminated shear strengths of Plywood flooring were high, 14.02 kgf/cm² at mole ratio of 1.4. At the mole ratio of 1.0, Plywood flooring showed low value of formaldehyde emission of 0.26 mg/L.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.30-37
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• 2006

The present study examined the formaldehyde (HCOH) emission characteristic of various wood-based panel used in interior design, and measured changes in formaldehyde emission when a number of VOC reduction methods were applied. Formaldehyde emission showed a clear tendency of increase with the rise of temperature, and the concentration of formaldehyde emitted changed according to the preprocessing condition before measuring. Formaldehyde emission from wood board after bake out treatment was lower than that of the control group. When specimens were coated with urethane, cashew, water, oil stain, they generally showed the decrease of formaldehyde emission, although varying according to finishing material, and when edge sealing was applied the decrease became significant. $TiO_2$ coating was more effective in decreasing formaldehyde under ultraviolet lamps than under ordinary lamps. When the irradiation of ultraviolet lamps gets longer, formaldehyde emission decreased.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.24-37
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• 2007

The Korean Ministry of Environment started controlling indoor air quality (IAQ) in 2004 through the introduction of a law regulating the use of pollutant emitting building materials. The use of materials with formaldehyde emission levels above $1.25 mg/m^2{\cdot}h$ (JIS A 1901, small chamber method) has been prohibited. This level is equivalent to the $E_2$ grade ($>5.0mg/{\ell}$) of the desiccator method (JIS A 1460). However, the $20{\ell}$ small chamber method requires a 7-day test time to obtain the formaldehyde and volatile organic compound (VOC) emission results from solid building interior materials. As a approach to significantly reduce the test time, the field and laboratory emission cell (FLEC) has been proposed in Europe with a total test time less than one hour. This paper assesses the reproducibility of testing formaldehyde and TVOC emissions from wood-based composites such as medium density fiberboard (MDF), laminate flooring, and engineered flooring using three methods: desiccator, perforator and FLEC. According to the desiccator and perforator standards, the formaldehyde emission level of each flooring was ${\le}E_1$ grade. The formaldehyde emission of MDF was $3.48 mg/{\ell}$ by the desiccator method and 8.57 g/100 g by the perforator method. To determine the formaldehyde emission, the peak areas of each wood-based composite were calculated from aldehyde chromatograms obtained using the FLEC method. Formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and benzaldehyde were detected as aldehyde compounds. The experimental results indicated that MDF emitted chloroform, benzene, trichloroethylene, toluene, ethylbenzene, m,p-xy-lene, styrene, and o-xylene. MDF emitted significantly greater amounts of VOCs than the floorings did.

• Journal of the Korea Furniture Society
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• v.11 no.1
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• pp.53-59
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• 2000

This study was to measure formaldehyde emission and bonding strength of plywoods manufactured with urea-melamine formaldehyde adhesives, which were made from three different mixing ratios of urea and melamine, and with four different formaldehyde/urea-melamine molar ratios of 1.0,1.1,1.2 and 1.4. The results were as follows 1. Amount of formaldehyde emission was the lowest at the first method of molar ratio(F/(M+U)) 1.0. Amounts of formaldehyde emission of experimental manufactured adhesives were lower than that of commercial adhesive. 2. Bonding strength of dry specimen was the highest at the first method of molar ratio(F/(M+U)) 1.4. Dry bonding strength of molar ratio(F/(M+U)) 1.4 was similar to commercial adhesive. 3. Bonding strength of wet specimen was the highest at the second method of molar ratio(F/(M+U)) 1.4. Bonding strength of wet specimen used by the third method of molar ratio(F/(M+U)) 1.4 was almost equal to commercial adhesive.