• Fire Science and Engineering
• /
• v.34 no.4
• /
• pp.13-21
• /
• 2020

This study tested the wood used in building interiors; each type had various incident heat fluxes based on their thickness. The combustion characteristics measured were effective heat of combustion, heat release rate peak and arrival time, maximum average rate of heat emission, and piloted ignition temperature. The wood specimens used in the experiment were 4.8 to 18 mm thick. 25, 35, 50, and 60 kW/㎡ were applied to the incident heat flux that the wood specimens were exposed to. The wood specimens tested were two types of medium-density fiberboard (each with a different density), treated red pine, particle board, and plywood. A comprehensive comparison of different fire characteristics was conducted to analyze the fire patterns corresponding to each type of wood in this way, the risk of fire was studied. The risk of fire was particularly high for particle board. The results of quantifying the fire characteristics of the types of wood studied could function as important input data with which to calculate the fire load of composite combustibles.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.2
• /
• pp.165-171
• /
• 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
• /
• v.27 no.1
• /
• pp.64-71
• /
• 1999

This study was conducted to manufacture MDF panels bonded with PF resins which provide excellent durability and dimensional stability with panels, and to identify benefits and weaknesses of using PF resins for MDF panels that have been manufactured with urea-formaldehyde (UF) resins for interior applications due to its low dimensional stability under moisture conditions. The results showed that the performance of PF-bonded MDF panels satisfied the performance requirement. A six-cycle aging test also revealed that PF-bonded MDF panels had high durability. Thickness swelling after 24 hours submersion in cold water was less than 2 percent, showing good dimentioanl stability. The identified weaknesses of using PF resins were relatively high resin content and long hot-pressing time. An acceptable resin content appeared to be 8 percent which can increase the production cost of PF-bonded MDF panels. The hot-pressing time (7 minutes) used in this study is relatively long compared to that of UF-bonded MDF panels. This result also indicates that hot-pressing process has to be optimized to control various pressing variables.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.44 no.4
• /
• pp.1-7
• /
• 2012

The increase of OCC solid content after wet pressing will save drying energy greatly. We applied spacers, which used to increase draining rate and bulk in fiber furnishes, to increase the OCC solid contents. MDF fibers (fibers for making medium density fiberboard) and diatomaceous earth were used as spacers, and added 10% by weight to the OCC fiber furnish. Application of high wet pressing pressure to the mixed furnish of spacers and refined OCC did not deteriorate bulk and drainage rate, but their solid contents were increased to 0.5-1.5% without loss of compressive strength when compared to those of unrefined OCC, which is the furnish normally used for mill commercial practice. It is believed that the spacers caused the rate of solid content increase faster in the mixed furnish with OCC at high wet pressing pressure area than the unrefined OCC furnish did. Little amount of starch addition (0.5%) to the spacers helped to keep the strength properties.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.5
• /
• pp.580-587
• /
• 2017

Woodfiber insulation board can be considered as a one of the key material for low energy consumption, comfortable and safety construction of residential space because of its eco-friendly and high thermal insulation performance. This study was carried out to investigate the formaldehyde (HCHO) total volatile organic compounds (TVOC) emission properties and combustion shapes by flame test of low density fiberboards (LDFs) prepared with different adhesives. HCHO TVOC emission and combustion properties of LDFs prepared by melamine urea formaldehyde (MUF), phenol formaldehyde (PF), emulsified methylene diphenyl diisocyanate (eMDI) and latex resin adhesives were measured by desiccator method, 20 L chamber method, and flame test, respectively. As results, LDFs manufactured by MUF, eMDI and latex resin adhesives satisfied the Super $E_0$ grade of HCHO emission performance except PF resin. Furthermore, TVOC emission of all LDFs were satisfied the Korean indoor air quality standard (below $400{\mu}g/m^2{\cdot}h$). Especially, LDF with eMDI resin adhesive showed the lowest HCHO and TVOC emissivity, that $0.14mg/{\ell}$, $12{\mu}g/m^2{\cdot}h$, respectively. However, eMDI emitted the small amount ($3{\mu}g/m^2{\cdot}h$) of toluene in VOC components. In the flame test, LDF with MUF resin adhesives showed the most favorable shape after flame test compare to LDFs prepared other adhesives. Based on HCHO and TVOC emission, and combustion shapes, MUF resin adhesive may be recommended to prepare LDF for insulation purpose.

• Journal of the Korean Wood Science and Technology
• /
• v.17 no.2
• /
• pp.34-64
• /
• 1989

Corner block with anchor bolt(CBA) joint method used in knock-down type table furniture manufacturing can reduce the packing and transporting cost. Unfortunately. it also has the disastrous defect to be loosend and unstable during the service life mainly due to fatigue and creep(repeated and prolonged loading). So 22 joint groups constructed were tested to evaluate the effect of some design factors related to the size of side rail(apron). block attachment to side rail. and the number of anchor bolt as well as the effect of the type of corner block(mitered type vs. rectangular type) Usable strength from the stiffness coefficients of each joint group were analysed with SPSS /PC+ and described as the criteria of CBA joint construction. The conclusions were as follows: The height of side rail(50, 75 and 100 mm) and the addition of polyvinyl acetate(PVAc) emulsion in the corner block attactment to side rail had the effect on raising the usable strength of CBA joint with remarkable high significance. And the effect of 2 - anchor bolts was also superior to that of 1 - bolt significantly. However. the thickness of side rail(22 mm vs. 25 mm) had no effect on the strengthening the table joint rigidity. Mitered type corner block joint appeared to he recommendable for CBA jointed table construction rather than the rectangular type one regardless of the method of block attachment to side rail. The best result identified from Duncan's multiple comparison was in the construction with 25 mm thick and 100 mm height of side rail fastened using 2 - anchor bolts in mitered type corner block. But it would be reasonable to use 22 mm thick & 75 mm high side rail and mitered corner block with PVAc emulsion & 2 bolts considering the productivity and production cost down in the MDF furniture manufacturing industries.