• Journal of the Korean Wood Science and Technology
• /
• 제26권4호
• /
• pp.50-55
• /
• 1998

This study was carried out to develop low density board made of rice hull which needs proper use. Urea formaldehyde adhesive(UF) was used. The raw materials were the mixtures of the rice hulls from IllFum, DongGin, ChuChong, etc. The physical and mechanical properties of rice hull insulation board were examined. The results are as follows : For the thickness of 15mm of the low density rice hull board bonded with UF resin, proper manufacturing conditions were $171^{\circ}C$ of hot pressing temperature with thickness bar for optimum density, 12 percent of resin solid contents of rice hull ovendry weight, and 20 minutes of hot pressing time. These conditions meet Korean standards(KS 3201-1982) in relation to free formaldehyde emission, bending strength, water absorption and heat resistance.

• Journal of Forest and Environmental Science
• /
• 제36권3호
• /
• pp.219-224
• /
• 2020

Urea formaldehyde resins are widely used in the manufacturing of wood composite and their usage is always combined with release of formaldehyde characterized to be hazardous to health during and after the manufacturing of the products. This study investigates the effectiveness of wood-based adhesive from oil of pyrolysed Triplochiton scleroxylon sawdust for the production of composite board. The wood-derived Pyrolytic Oil (PyO) was blended with Urea Formaldehyde (UF) resin to formed Pyrolytic Oil-Urea Formaldehyde (PyOUF). The obtained PyOUF called Wood-Based Adhesives at four blends and control (UF) viz; 1:1, 1:2, 1:3, 2:1, 1:3 were further employed to prepare the composite board and test for their bonding strength by physical (water absorption-WA and thickness swelling-Th.S) and mechanical properties (modulus of elasticity-MOE, modulus of rupture-MOR, and impact bending-IB). Data obtained was analysed using analysis of variance at α 0.05. The result of analysis of variance conducted on physical properties show significant difference (p≤0.05) between the WA values obtained when testing the different blending proportion of PyOUF and likewise between 2 and 24 h of immersion. PyOUF had significant effect (p≤0.05) on Th. S for 24 h but no significant different (p>0.05) for the 2 h period of soaking. The analysis of variance on mechanical properties of the composite board (MOE, MOR, and IB) show significance differences (p≤0.05) between the strength values obtained when testing the different ratios of PyO with UF. PyO content influenced the properties of the boards and it is evident that PyO can be used in the manufacture of composite board.

• 한국산림과학회지
• /
• 제96권1호
• /
• pp.54-57
• /
• 2007

요소수지접착제를 합판제조용 접착제와 유사하게 실험실에서 합성하고, 합성한 요소수지접착제를 증량제, 충전제, 산경화촉매제와 혼합하였다. 요소수지접착제 혼합물의 고형분량은 56.1%이고, 물은 43.9%였다. 국산재와 요소수지접착제 혼합물로 5종류의 Com-Ply를 제조하고, KS F 3101 보통합판의 인장 전단 접착력 시험 및 KS F 3104 파티클보드의 휨파괴계수 시험을 수행했다. 성능 평가된 결과는 제조된 5종류의 Com-Ply에서 모두 적합한 결과를 보여줬다. 이런 결과는 본 연구에서 사용된 요소수지접착제 혼합물이 국산재 Com-Ply제조에 적합하다는 것이다.

• 한국가구학회지
• /
• 제22권3호
• /
• pp.174-182
• /
• 2011

Over the last decade, Sick Building Syndrome has become a significant social issue in Korea and many methods have been considered to maintain comfortable indoor air quality. To reduce toxic substances emitted from wood composite products, the source control is an efficient method through the reduction of formaldehyde content by using natural material-based adhesives for composite wood products production. Among alternative materials, soybean protein is considered an appropriate natural material to replace formaldehyde-based resin and many efforts have been made to produce new products, such as soap, shampoo, ink, resin, adhesive and textile through changing the chemical or physical properties of soybean. To process soybeans into these useful products, the beans are dehulled and the oil is removed by crushing at very high pressure or by solvent extraction. For use soybean as an adhesive, it is processed at temperatures below $70^{\circ}C$ to preserve the alkaline solubility of the proteins. In addition, soybean-based adhesive is undergone treatment process to improve mechanical properties using urea, urease inhibitor N-(n-butyl) thiophosphoric triamide and sodium dodecyl sulfate. The modified soybean-based adhesive exhibited sufficient mechanical properties to use as an adhesive for composite wood products. This paper is a review article to discuss the possibilities of soybean-based adhesive for environment-friendly furniture materials.

• Journal of the Korean Wood Science and Technology
• /
• 제45권2호
• /
• pp.223-231
• /
• 2017

This work was conducted to investigate on the effect of urea-formaldehyde (UF) resin viscosity on plywood adhesion. The viscosity of UF resin was controlled either by adjusting the condensation reaction during its synthesis to obtain different target viscosities (100, 200 and 300 mPa.s) at two levels of formaldehyde/urea (F/U) mole ratios (1.0 and 1.2) or by adding different amounts (10, 20 and 30%) of wheat flour into the resins for the manufacture of plywood. When the viscosity of UF resin increased by the condensation reaction, the adhesion strength of plywood bonded with UF resin of 1.2 F/U mole ratio consistently increased, while those bonded with the 1.0 F/U mole ratio resin slightly decreased, suggesting a difference in the adhesion in plywood. However, the adhesion strength of plywood decreased as the viscosity increased by adding wheat flour, regardless of F/U mole ratio. The manipulation of UF resin viscosity by adjusting the condensation reaction was much more efficient than by adding wheat flour in improving the adhesion performance of plywood. These results indicated that a way of controlling the viscosity of UF resin adhesives has a great influence to their adhesion in plywood.

• 한국가구학회지
• /
• 제22권3호
• /
• pp.219-229
• /
• 2011

Sick building syndrome symptoms that are experienced by building occupants may be caused by toxic substances such as formaldehyde and VOCs, which are known to be emitted from building materials and wood composite products such as wood-based panel, furniture, engineered flooring and construction adhesive. In Korea, the use of wood composite products for indoor environments has increased over the last decade. Recently, wood composite products have been installed in approximately 95% of newly constructed residential buildings. The use of these products has resulted in problems related to human health, and consequently a realization about the importance of indoor air quality. In addition, consumer demand is increasing for natural materials because conventional building materials and wood composite products are made by adding urea-formaldehyde resin or they contain formaldehyde-based resin. More recently, many efforts have been made to reduce formaldehyde emission from building materials that laid in the indoor environment. Especially, if conventional formaldehyde-based adhesives are replaced with green adhesives for residential spaces, it is possible to reduce most of the emission amounts of formaldehyde in indoor environments. In line with this expectation, many researches are being conducted using natural materials such as tannin and cashew nut shell liquid (CNSL). This study discussed the affects and possibilities of green adhesives to reduce formaldehyde emission in indoor environments.

• Journal of the Korean Wood Science and Technology
• /
• 제45권4호
• /
• pp.409-418
• /
• 2017

This work attempted to manufacture glued-laminated timber (Glulam) bonded with melamine-urea-formaldehyde (MUF) resin adhesives at various melamine contents from 20% to 50% under high frequency (HF) heating for a very short time. Two preparation methods were employed to prepare MUF resin adhesives with different melamine contents: one-batch method of synthesizing MUF resins in a single batch, and two-batch method of mixing urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized separately. As the melamine content increased, the gelation time and peak temperature of MUF resins decreased. The adhesion performance of plywood showed that the one-batch MUF resin adhesive with 50% melamine content only satisfied the standard requirement of water resistance. Thus, the one-batch MUF resin adhesive with 50% melamine content was applied for bonding wood lamina from four softwood species such as Japanese larch, Korean red pine, Korean pine and Japanese cedar to manufacture Glulam under HF heating. All Glulam samples bonded with the one-batch MUF resin adhesives with 50% melamine content except those from Korean Red Pine satisfied the requirement in water soaking or boiling water delamination test as an exterior grade Glulam. The presence of rosin in Korean Red Pine was believed to be responsible for its poor adhesion. These results showed that the one-batch MUF resin adhesives with 50% melamine content provided acceptable water resistance with exterior grade Glulam manufactured under HF heating.

• 한국가구학회지
• /
• 제11권2호
• /
• pp.73-78
• /
• 2000

This study was carried out to measure formaldehyde emission with the passing of two years from plywood, sliver-board and strand-board bonded with urea resins which were made of 6 f/U molar ratios. The urea resins were manufactured by six kinds of formaldehyde/urea molar ratio of 1.0, 1.2, 1.4, 1.6, 1.8 and 2.0. 1. The plywood with molar ratio of 1.0 satisfied the KS F3101 $F_2$ directly after manufacture. The plywood with molar ratio of 1.2 satisfied m 3 days. The plywood with molar ratio of 1.4 satisfied the $F_3$ in 3 days and the $F_2$ in 600 days. And the plywood with molar ratio of 1.8 and 2.0 satisfied the $F_3$ in 365 days, but didn't satisfy the $F_2$ in 730 days. 2. Sliver-board with molar ratio of 1.0 and 1.2 satisfied the KS F3104 $E_2$ right after manufacture. Sliver-board with molar ratio of 1.4 and 1.6 satisfied in 150 and 360 days, respectively. Sliver-board with molar ratio of 1.8 and 2.0 satisfied in 730 days. 3. Strand-board with molar ratio of 1.0 and 1.2 satisfied the KS F3104$ E_2$ directly after manufacture. Strand-board with molar ratio of 1.4 and 1.6 satisfied in 150 days. But Strand-board with molar ratio of 1.8 and 2.0 didn't satisfied in 730 days.

• Journal of the Korean Wood Science and Technology
• /
• 제9권3호
• /
• pp.16-23
• /
• 1981

요소수지(尿素樹脂)를 접착제(接着劑)로 사용(使用)한 수질품종중(水質製品中) 합판(合板)은 건축내장(建築內裝) 및 가구(家具), 후래쉬도아, 마루판등(等) 광범하고 다양한 용도로 주거환경(住居環境)에 사용(使用)되고 있다. 그런데 이러한 합판중(合板中) 요소수지접착층(尿素樹脂接着層)으로부터 유리(遊離) 또는 분해(分解)되어 방출(方出)되는 포름알데히드는 유독(有毒)한 화학약제로서 극소량의 농축으로도 불쾌감, 두통(頭痛) 및 인체(人體)에 위험을 실제로 초래하고 있다. 따라서 이러한 유리포름알데히드를 제거 또는 조절하여 소위 "포름알데히드 문제"를 해결(解決)하는 처리방법(處理方法)에 목표를 두고 탈(脫)포름알데히드효과(效果) 및 합판(合板)의 재질(材質)에 미치는 효과(效果)를 상호 비교(比較)하고 그 개선점(改善點)을 밝히고자 하였다. 개량(改良)크로모토로픽산(酸) 방법(方法)으로 유리포름알데히드를 정량(定量)하였으며 주로 접착제제조(接着劑製造) 및 혼합(混合)에 중점을 두고 제거제(除去劑)를 첨가할 때의 효과(效果)를 비교(比較)하였으며 도포방법(塗布方法)은 요소처리(尿素處理)에 한(限)하였다. 결과(結果)는 다음과 같이 요약(要約)할 수 있다. 1. 요소용액(尿素溶液)침지처리와 경화제처리(硬化劑處理)가 가장 좋은 유리포름알데히드방산제거효과(放散除去效果)를 가져 왔으며, 리조시놀 4%, 알부민처리(處理)도 좋은 결과(結果)를 가져왔고 수피분증량처리도 그 가능성이 있음을 볼 수 있다. 2. 합판접착강도(合板接着强度)는 상태접착강도(常態接着强度)에서 모든 처리(處理)가 전부 규격에 합격(合格)하여 특히 리조시놀 2%와 요소용액침적처리(尿素溶液沈積處理)가 월등히 높았고, 2류합판(類合板)온수시험에 의(依)한 접착강도(接着强度)는 경화제처리(硬化劑處理)로만 불합격(不合格)이고 리조시놀 2%가 대비합판(對比合板)에 비(比)하여 좋은 강도(强度)를 보였고 수피(樹皮), 요소처리(尿素處理)가 대비(對比) 합판(合板)보다 강도(强度)가 높았다. 3. 처리합판(處理合板)의 기건함수율(氣乾含水率)은 11~13% 사이로 모두 규격(規格)을 만족시켰다. 4. 리조시놀, 알부민과 요소용액침적처리(尿素溶液沈積處理)의 혼합효과(混合效果)는 계속 연구(硏究)하면 더 좋은 결과(結果)를 획득하리라 사료된다.

• Journal of the Korean Wood Science and Technology
• /
• 제31권1호
• /
• pp.22-26
• /
• 2003

증량제로서 카제인과 콩을 첨가한 요소수지 접착제와 소나무 간벌재 파티클로 실험실 파티클보드를 제조하였다. 소나무 간벌재 파티클로 제조된 파티클보드를 성능 평가한 결과 소나무 간벌재는 파티클보드의 원료로서 적합하다. 증량된 요소수지로 접착된 파티클보드는 증량제의 첨가량이 증가함에 따라 기계적인 성능은 감소하는 경향이었다. 그러나 요소수지 접착제의 고형분량에 대해 카제인은 15%까지 콩은 20%까지 첨가하여 파티클보드 제조에 사용할 수 있다.