This study was conducted in order to measure formaldehyde emission with the passing of time from plywood, parricleboard-1 and parricleboard-2 bonded with urea-tormaldehyde resin. The six kinds of UF resins were manufactured with formaldehyde/urea molar ratio 1.0, 1.2, 1.4, 1.6, 1.8 and 2.0. The boards were made of three kinds of raw materials; veneer, particle-1 and particle-2. Formaldehyde emission contents were measured at 1,3,7,15, and 30 days after boards were manufactured. The results were as follows: 1. Free formaldehyde content in UF resins increased greatly with increasing of F/U molar ratio. Free formaldehyde contents increased 86.3%, 250%, 547%, 983%, 1600% in F /U molar rano 1.2, 1.4, 1.6, 1.8, 2.0, respectively, compared to that in F /U molar ratio 1.0 2. The plywoods manufactured with UF resins of 1.0, and 1.2 molar ratios satisfied the KS formaldehyde emission limit of 5 mg/ I directly after manufacturing. The plywood with F /U molar ratio 1.4 satisfied KS limit of 10mg/ I only in 30 days. 3. The particleboard-1 and particleboard-2 satisfied the formaldehyde emission limit of KS standard U type with 1.0, 1.2 molar ratio. The particleboards manufactured with the other molar ratios 1.4, 1.6, 1.8, 2.0 didn t satisfy. KS standard U type in 30 days. 4. The amount of formaldehyde emission were not strongly dependent on their period of emission after the manufacture of board, but dependent on their molar ratio. The types of raw material differently showed different their emission rate and pattern.
1. 緖論
2. 材料 및 方法
3. 結果 및 考察
4. 結論
5. 引用文獻