• Journal of the Korean Wood Science and Technology
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• 제49권6호
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• pp.574-590
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• 2021

전 세계적으로 불법목재 방지를 위한 국제적 노력이 확대되고 있으며, 우리나라는 국내에 수입·유통되는 목재의 합법성을 강화하기 위하여 2019년 '합법목재 교역촉진제도'를 시행하고 있다. 합법목재 교역촉진제도는 목재, 목재제품 등을 수입할 시 생산 국가, 수종, 벌채지 등에 대해 합법한 목재임을 입증하는 제도이다. 입증 방법에는 주로 DNA 분석 기술과 현미경을 이용한 해부학적 특징 분석이 함께 이용되고 있다. 따라서, 본 연구에서는 다양한 목재제품 중에 우선적으로 합판의 해부학적 특성을 분석하여 수종 식별을 하였다. 공시재료는 합판 생산 기업의 합판(7, 9ply)을 취급하는 4업체를 선정하여 미송(Pseudotsuga menziesii (Mirb.) Franco.) 및 낙엽송(Larix kaempferi (Lamb.) Carriere)합판을 구입하여 시료를 확보하였다. 각 회사의 합판을 약 1cm³ 크기로 절삭한 뒤, 표판부터 이판까지 하나의 단판으로 분리하여 광학현미경을 이용하여 3단면을 관찰하였다. 수종식별 결과, 침·활엽수 혼합 합판과 소나무류, 포플러류, 낙엽송·소나무류의 혼합으로 구성되어 있었다. 현미경법을 이용한 목재의 수종식별은 무분별한 불법 목재의 유통 및 불법 벌채 위험국가로부터 수입되는 합판을 비롯한 다른 여러 가지 목재 제품을 과학적으로 분석·검증할 수 있는 중요한 분야이다

• 한국화재소방학회논문지
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• 제15권3호
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• pp.55-62
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• 2001

본 연구는 국내와 외국의 건물 내장재 화재성능평가방법을 고찰하고 국내에는 도입되지 않은 실대 화재실험인 Room Corner Test를 국내 내장재중 석고보드와 합판을 대상으로 그 적용성을 위한 실험을 진행하였다. 현재 국내 내장재의 평가규정은 Bench-Scale Test에 의존하고 있으나, 미국, 일본 유럽등에서는 Room Corner Test를 적용한 실질적인 재료의 화재성능평가를 시행하고 있다. 실험 결과, NFPA 265에 의한 석고보드 및 ISO 9705에 의한 합판의 성능은 양호한 것으로 판단되었다. 현재 국내 내장재에 적용되는 등급분류의 평가방법은 재료의 실제 화재성능 평가에 한계가 있으므로 향후 Room Corner Test의 적용과 더불어 Bench-Scale Test 결과를 토대로 화재성능을 예측하는 화재모델을 이용하는 평가 방법의 도입이 필요하다.

• Journal of the Korean Wood Science and Technology
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• 제16권3호
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• pp.5-16
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• 1988

This experiment was executed to investigate the effect of activation of veneer surface by oxidizing agents, hydrogen peroxide and nitric acid, on bonding characteristics of Malas(Homalium foetidum Benth) plywood, in which the effects of these oxidizing agents amount, pretreatment time, and pressing time and temperatue on shear strength of the plywood were examined and discussed. In this research the activation of veneer surface by oxidants was effective in raising shear strength but the difference in shear strength was not observed between hydrogen peroxide and nitric acid treatment. Hydrogen peroxide treatment, however, seemed to be more profitable to industrial application because of its lower concentration and easier handling than nitric acid. The bonding method by lignin-phenol adhesive through surface activation revealed inferior shear strength to phenol- and urea-formaldehyde adhesive but superior water resistance to urea-formaldehyde adhesive and this bonding method, in addition, have the advantage of lower cost compared with phenol-formaldehyde adhesive, Therefore, this bonding method by lignin-phenol adhesive through surface activation seemed to economical in manufacturing of water-resistant wood panel materials in future.

• Journal of the Korean Wood Science and Technology
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• 제15권4호
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• pp.64-68
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• 1987

To develope the utilities of the chestnut bur, which is wasted after harvesting chestnut in farmhouses, the feasibilities of adhesion(urea resin) extenders of the powder for plywood were examined. These experiments were implemented on experimental scale at Forestry Research Institute(Seoul) and on a plywood mill scale at Eugon Industrial Co LTD(Inchon) for more reliable data. In this paper, it was proved that the chestnut bur powder caused to rise the glue viscosity but the chaff powder to down reversely. The most effective mixing ratio were wheat flour 5kg, chaff powder: 5kg and chestnut bur powder. 5kg per 100kg of urea resin. At this condition, the viscosity were most appropriate (1,320 2,230 cps) for glue spreading operations, and the dry shear strengthes were most adequate(10.7-13.2kg/$cm^2$), wood failure ratio 82-88%). The chestnut bur powder, can be utilized for plywood adhesion extenders without any change of present process lines in plywwod mills.

• Journal of the Korean Wood Science and Technology
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• 제16권1호
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• pp.3-8
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• 1988

This study was carried out to examine the effect of pretreatment of veneer with aluminum sulfate solution for the manufacture of the kapur plywood on the reduction of urea resin spread. The results were as follows: 1. Specific gravities of plywoods made of the kapur veneers ranged from 0.83 to 0.84 and their moisture contents based on air dry weight showed from 10.6% to 11.4%. These met the Korean Industrial Standards. 2. In the case of dry shear strength for the 3rd class plywood, 40% reduction- spread met K S as well as normal urea resin spread. pH of the aluminum sulfate solution gave better result at pH 4.5 and pH 6 than at pH 3. For the manufacture of the 2nd class plywood, hot and cold water-wet shear strength show the best results at the following conditions; such as 20% reduction spread, pH 4.5 of aluminum sulfate solution and all veneer treatment.

• Journal of the Korean Wood Science and Technology
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• 제20권2호
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• pp.31-42
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• 1992

In this study, the relative effectiveness of antimony trioxide-containing coat on fire retardancy of plywood, particleboard and medium density fiberboard was investigated and compared through ISO ignition test and inclined panel test with non-coated ones. The results obtained were summarized as fallows: Any treated materials was not ignited in inclined panel test with 5 minutes, but only particleboard among treated ones burned in ISO ignition test with fairly delayed time. The weight loss rate of plywood decreased with the increased addition level of fire-retardant and the least values were obtained in particleboard and MDF at addition level of 7% and 5% respectively. Carbonized area of wood based materials decreased with the increased addition level of fire retardant. The temperatures of back in plywood, particleboard treated with fire-retard ant coat containing 7% $Sb_2O_3$ showed the lowest but MDF did not show any effectiveness with the increased addition level. The first flash time of plywood treated with fire retardant coat containing 9% $Sb_2O_3$, MDF and particleboard treated with fire retardant coat containing 7% $Sb_2O_3$ were 257sec., 286.4sec., 165.4sec. respectively.

• Journal of the Korean Wood Science and Technology
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• 제43권2호
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• pp.258-264
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• 2015

To evaluate the influence of 3A zeolite on the flame retardant properties of poplar plywood. Ammonium polyphosphate (APP) and 3A zeolite were used as flame retardants to prepare plywood samples. The combustion properties, such as heat release rate (HRR), total heat release (THR), mean CO and $CO_2$ yield, smoke production rate (SPR), and total smoke production (TSP), were characterized by a cone calorimeter. A synergistic effect was observed between 3A zeolite and APP on reducing the HRR and mean CO yield. The probable flame retardation mechanism was proposed.

• Journal of the Korean Wood Science and Technology
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• 제47권5호
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• pp.579-586
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• 2019

This work examined effects of the synthesis method and melamine content of melamine-urea-formaldehyde (MUF) resins on the bond-line features (i.e. resin penetration and bond-line thickness) in plywood. Two synthesis methods (MUF-A and MUF-B) and three melamine contents (5, 10, and 20%) were employed to prepare MUF resins. The MUF-A resins at three melamine contents were prepared by a simultaneous reaction of melamine, urea, and formaldehyde, while the MFU-B resins were prepared by reacting melamine at the same levels with formaldehyde followed by urea. The results showed that higher melamine content increased the viscosity of MUF-A and MUF-B resins. The resin penetration of MUF-A resins decreased by 48% while those of MUF-B resins increased by 16% at 20% melamine content. As a result, the MUF-A resins had greater bond-line thickness than those of MUF-B resins as the melamine content increased. The MUF-B resins resulted in thinner bond-line and greater resin penetration compared to those of MUF-A resins. The results suggested that MUF-B resins prepared with 20% melamine content had a proper combination of resin penetration and bond-line thickness that could produce plywood panel with a better adhesion performance.

• Journal of the Korean Wood Science and Technology
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• 제49권1호
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• pp.93-102
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• 2021

In this article, withdrawal resistances of axially loaded self-tapping screws on wood products made by Korean Larch were predicted with existing estimation equation, and compared with experimental test data. The research was required because no design methodology for the withdrawal resistance of self-tapping screw is present in Korean building code (KBC). First, the withdrawal resistance of wood screw was predicted to use the withdrawal design value estimation equation in National Design Specification for Wood Construction (NDS). Second, three types of wood products, solid wood, cross-laminated timber (CLT) and plywood, were utilized for withdrawal test. For decades, various engineered wood products have been developed, especially cross-laminated timber (CLT) and hybrid timber composites such as timber composites of solid wood and plywood. Therefore, CLT and plywood were also investigated in this study as well as solid wood. Finally, the predicted values were compared with experimentally tested values. As the results, the tested values of solid wood and CLT were higher than the predicted values. In contrast, it is inaccurate to predict withdrawal resistance of plywood since prediction was higher than tested values.

• 대한안전경영과학회지
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• 제25권1호
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• pp.61-66
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• 2023

The purpose of this study is to compare and analyze the flame retardant performance of Japanese cypress(Chamaecyparis obtusa) plywood, commonly used in indoor decoration, furniture, and tableware, by treating it with three different fire retardants with different primary ingredients. The experiment was conducted in compliance with Article 31, Paragraph 2 of the Enforcement Decree of the Fire Facilities Installation and Management Act and Articles 4 and 7-2 of the Flame Retardant Performance Standards. After flame time, after glow time, char length, and char area were measured. As a result, first, after flame time was measured at 0 seconds regardless of whether the flame retardant treatment was applied. Second, after glow time was relatively long, measuring 22.7 seconds without treatment, which is likely due to the weak fire resistance and high concentration of carbon monoxide generated by the chemical characteristics of the Japanese cypress itself. Third, it was confirmed that the effects of the primary ingredient, phosphorus, in the flame retardant treatment varied depending on the technological development of the manufacturers of the same species of Japanese cypress plywood. In the future, it is expected that the results of this study will provide fundamental data to select flame retardant treatments that show high flame retardant performance according to the botanical characteristics of the wood.