國產樹種定向粒片板製造及工程性能之評估

Abstract

本研究之目的在於研發國產樹種應用於定向粒片板之製造，並預期能符合商用木質板材之性質要求，及家居生活及工程上之需求，輔以非破壞性試驗、耐燃性試驗及甲醛釋出量之測定等，俾便於擴展木質板材之應用範圍及安全性能。研究結果如下： 長薄片型粒片之切削，應先浸冷水軟化處理並施以橫向切削，定向裝置則以柵狀高低隔板式之振動篩最佳。板表面薄片之木理方向與定向方向所成角度之定向角0-15°時，己達73-82%，定向效果相當優良。柳杉、杉木OSB之平均定向角度，表面為10°-14°；台灣泡桐OSB，表面為21°-23°。 OSB之剖面密度及鑽孔抵抗之阻抗圖譜，大都有表底層密度值較大而中心層較小之趨勢。用膠量6.5%時，木螺絲保持力符合要求；吸濕膨潤率以厚度最大，橫向次之，縱向最小；靜曲強度性質符合CNS之標準。MOR異方性為2.68 - 5.59，而MOE之異方性則為4.78 - 10.9。MOR與MOE的關係均為正相關。 全板之音速值，V//為4234∼4632 m/sec，V

This research was to study the application of domestic species to the manufacture of OSB (Oriented Strand Board) and the possibility to fit the demand of the needed properties of wood based panel in commercials. Besides, for the safety consideration both on the human livings and engineering, and the need in grading wood based panel qualities, this study also included the experiments on the Nondestructive Test, Fire-Retardant Test and Emission Formaldehyde Test. Therefore, the collected information could be used on grading where the wood based panel is possibly applied to and on evaluating how safe it would offer. The results are as follows: 1. The flake should be done by dipping into cold water for socking moisture to reduce the resistance of cutting. The direction of cutting was perpendicular to the grain. The most appropriate alignment for the flake should be screened by the uneven screens mounted on the screen frame. As the accumulation of orientation rate from flake’s aligned angles of face layer was within 0° - 15°, the percentage would reach to 73 – 82 % on the OSB. Then, the effectiveness was excellent. On the face layer of the Japanese-fir and China-fir OSB, the weighted average of aligned angle was about 10°-14°, 21°-23° to the Paulownia OSB. 2. About the OSB density profile behavior, except JSP OSB, all showed significantly high phenomena on the bottom and face layer, but low in the core. The resistograph obtained from the drill resistance test would show density profile curve. There were correlations between the index of Pdi, PA, GF, Pb and the thickness swelling, MOE//, MOE⊥. To the screw holding, the 6.5 % resin content OSB was qualified to the demand. As the absorption of MC% of OSB was increasing, the RH% increased. The MC% would be lower at 40 ℃, compared with 25 ℃. The OSB percentage of swelling would be large to the thickness direction, perpendicular alignment next and parallel alignment smallest. Most of the thickness swellings could match the requirement of CNS. The strength properties of OSB bending test to all of them reached the CNS standard. The orthotropic of MOR were 2.68 – 5.59, but 4.78 – 10.90 to the MOE. The linear regressions to the relationship between MOR// and MOE//, and MOR⊥ and MOE⊥ were significantly positive. 3. About the ultrasonic velocity to the board, the parallel to the alignment would be larger than perpendicular to the alignment: V// was 4234 – 4632 m/sec, V⊥ 1364 – 1652 m/sec, and V// / V⊥ 2.7 – 3.2. As the measuring angle was increasing, the ultrasonic velocity would decrease. It was resulted from the quadric regression. The regression was significantly negative. 4. The optimal n values for Hankinson’s formula were 1.83 –1.89 for China-fir OSB, 1.9 – 2.1 for Japanese-fir OSB, and 2.0 –2.1 for Japanese-fir bending test specimen. From the seven bending test specimens cut at different angles of JMP OSB, the ultrasonic velocity would be the largest at 0°, and it would drop sharply as the bending test specimens’ angle to the flake alignment increased. The ultrasonic velocity would be the smallest at 90°. The n value of Jacoby equation and n value of Hankinson’s formula were highly correlated. Compared at the orthotropic property, the orientation ratios of full board or bending specimen could reach to 70-80 % to the solid wood. About the optimal n values in Hankinson’s formula, MOR/ρ and MOE/ρ were quite similar to the solid wood in n value. The ultrasonic velocity, bending strength properties, and dynamic elastic property had significant positive correlations. 5. To the creep property, the phenomenon of deflection occurred instantly as loaded, about 20 – 23 % higher of Japanese-fir OSB to China-fir OSB. The relative creeps were less than 2. The remained ratio of MOE would mostly drop below 50 %; but, MOR would be 70 % higher, referring that the loss of the creep load elasticity would be higher that the plasticity. 6. To the solid wood, the Japanese-fir TGA curve was relatively unstable before reaching 300 ℃. However, the TGA curve and weight loss dropped sharply at the temperature between 341 – 374 ℃. This phenomenon was similar to the OSB. At the amount of residual-char, the Paulownia wood was topped to the first among those three species, 0.156 %. But, all of the OSB contained more than it. To the fire resistance of OSB, all met the requirement of CNS 6532 type III. About the emission of formaldehyde, China-fir was 0.6 and 1.0 for Japanese-fir, representing type E1. The formaldehyde emission would drop as the percentage of PMDI flake weight increased. It would drop to 0.3 mg/L below as reaching to 75 %.