不同調配條件液化木材/異氰酸酯製作低密度粒片板之性質

PROPERTIES OF LOW DENSITY PARTICLEBOARDS MADE BY LIQUEFIED WOOD/ISOCYANATE WITH DIFFERENT PREPARING CONDITIONS

李文昭(Wen-Jau Lee) ； 林孟萱(Meng-Shinan Lin) ； 陳奕君(Yi-Chun Chen)

《中華林學季刊》 49卷1期 (2016/03) Pp. 75-85

摘要

本研究將杉木(Cunninghamia lanceolata; China fir)及相思樹(Acacia confusa; Taiwan acacia)木材以聚乙二醇/丙三醇(PEG/Glycerol)混合液為溶劑，H_2SO_4為催化劑，以150℃加熱90 min進行液化處理。所得液化木材與PMDI、Desmodur L及Desmodur N三種異氰酸酯在NCO/(COOH＋OH)官能基莫耳數比1.0/1、1.5/1及2.0/1條件下調配聚胺基甲酸酯樹脂(Polyurethane resins; PU)。進一步則將此PU樹脂與木材粒片混合製作低密度粒片板，並探討木材粒片/PU樹脂重量比及發泡劑添加量對所製作粒片板性質之影響。由結果得知，以液化相思樹為多元醇原料所製作粒片板之性質優於以液化杉木為原料者。不同種類異氰酸酯比較，以Desmodur L為原料者有較高內聚強度，較低吸水厚度膨脹率。以PMDI為原料者有較低之吸水率及厚度膨脹率。隨NCO/(COOH＋OH)官能基莫耳數比增加，粒片板之內聚強度提高。發泡劑之適當添加量則依異氰酸酯種類而異，以PMDI為原料者添加量5%最佳；以Desmodur L為原料者，隨發泡劑添加量增加，粒片板性質提升；而以DesmodurN為原料者則隨發泡劑添加量增加，其粒片板之性質降低。

關鍵字

液化木材 ； 異氰酸酯 ； 低密度粒片板 ； 多元醇 ； 聚胺基甲酸酯樹脂

並列摘要

Woods of Cunninghamia lanceolata (China fir) and Acacia confusa (Taiwan acacia) were liquefied in PEG-glycerol co-solvent with H_2SO_4 as catalyst under 150℃ for 90 min. Polyurethane resins were prepared by blending liquefied wood with isocyanate, such as PMDI, Desmodur L and Desmodur N, with the molar ratio of functional group of NCO/(COOH+OH) as 1.0/1, 1.5/1 and 2.0/1. Theses PU resins were mixed with wood particles to made low density particleboards. Effects of the weight ratio of wood particle to PU resin used and the dosage of foaming agent added on the properties of particleboard was also investigated. Results showed that particleboards made with liquefied Taiwan acacia as the raw material of polyol had the properties better than that with liquefied China fir. Comparison among different isocyanates, particleboards made with Desmodur L as raw material had higher internal bonding strength and lower thickness swelling. Particleboards made with PMDI had lower water absorption rate and thickness swelling. Increasing the molar ratio of NCO/(COOH＋OH), the internal bonding strength of particleboard increased. The optimum amount of foaming agent was depended on the kind of isocyanate. When PMDI was used as the isocyanate, 5% of foaming agent was the best suitable. While the particleboards were made with Desmodur L, the performance of particleboards improved when the dosage of foaming agent increased. However, increasing the dosage of foaming agent, the properties of particleboard decreased for that made with Desmodur N as raw material.

並列關鍵字

Liquefied wood ； Isocyanate ； Low density particleboards ； Polyhydric alcohol ； Polyurethane resins