本研究之目的旨在以紅柳桉及放射松單板為試材,經三種濃度之矽酸鈉與四種無機塩類(氧化硼、硫酸鋅、氯化鎂、氯化鋅)飽和溶液之反應劑雙重處理後,製造五層9mm厚合板。依ISO 5660試驗標準,圓錐量熱儀以50 kW/平方公尺輻射熱通量加熱15 min,探討各藥劑處理合板之熱釋放率性質及其阻燃性改善效應。處理合板之藥劑重量增加率以矽酸鈉-氯化鋅及矽酸鈉-氯化鎂者較大,而矽酸鈉-硫酸鋅及矽酸鈉-氧化硼者較小。藥劑處理之合板發煙量(減光面積),隨藥劑重量增加率增加而增加。藥劑處理之合板熱釋放率、平均熱釋放率、熱釋放率峰值、總熱釋放率及平均有效燃燒熱等燃燒因子均隨藥劑重量增加率增加而降低且比未處理者低。熱釋效率峰值之阻燃性改善效應,則以矽酸鈉-氯化鎂、矽酸鈉-硫酸鋅及矽酸鈉-氯化鋅三者藥劑改善最佳,而矽酸鈉-氧化硼者最差。建議第一液矽酸鈉藥劑濃度20%為宜,以避免過多藥劑沉積試材表面,影響試材之外觀及後續表面加工處理。
Several heat releasing characteristics and fire-retardant improving efficiency of the 5-ply, 9 mm thick plywood, made of red lauan and radiata pine veneers, were evaluated according to ISO 5660 test methods. Cone calorimeter was used to measure the heat release rate of the plywood heated at 50 kW/m^2 for 15 minutes. Sodium silicate (SS) of three different concentrations was used as the first solution in the double diffusion treatment process and four inorganic salts as the second solutions. The use of zinc chloride and magnesium chloride as the second chemicals resulted in better performance than those of the zinc sulfate and boron oxide in weight gain of the processed plywood. Specific extinction area of the processed plywood increased with the increasing weight gains. The combustion factors of heat release rate, average heat release rate, heat release peak, total heat released and average effective combustion heat decreased with increasing weight gains and were lower than those untreated. The combination of SS and magnesium chloride, zinc sulfate and magnesium chloride gave better fire retardant improving efficiency while the application of boron oxide to incorporate with SS showed inferior effect for heat release peak. To maintain a clean surface of the processed plywood without excessive deposition, the recommended concentration for sodium silicate is 20% or less.