Grading technology of China fir sawn lumber and its properties by melamine formaldehyde resin impregnation

為提升木材自給率，近年國內鼓勵國產材之收穫與利用，並積極推動國產木竹材產銷履歷，然木材之有效利用首重其性質，因此，本研究之第一部分以國產杉木（Cunninghamia lanceolata）為主要材料，由原木端開始進行製材利用率與製材品之強度分級研究，並進行容許應力之推估，以提高木材之利用效率。另外為增廣其應用範圍，提升其於戶外使用之耐久性。而本研究之第二部分以三聚氰胺甲醛樹脂（Melamine formaldehyde resin, MF）進行杉木製品之改質處理，探討其改質處理後之機械性質、尺寸安定性與耐生物劣化性質。 由製材利用率之結果顯示，隨原木徑級增加其製材利用率亦隨之提高，製材品分級方面，以機械等級及GP（Grading parameter）等級區分具較佳之分級效果，目視等級區分則有強度變異性較大之問題。另CNS 14630（2017）針葉樹結構用製材之分級與CNS 14631（2002）框組壁結構用製材之分級兩種不同標準之比較顯示，以後者進行分等其3等材與等外材會有較高之分布比例；原木品等部分，隨目視等級提高，生產之製材品亦集中於較高之等級材，且強度性質亦隨之提升。第二部分MF改質處理之結果顯示，MF改質杉木之機械性質有提升之趨勢，改善效果方面以硬度最佳，抗壓強度次之，抗彎強度與抗剪強度則相對較不顯著；尺寸安定性方面，MF改質處理杉木之吸水率、體積膨脹率皆有下降之趨勢，且抗膨脹效能亦隨重量增加率之提高而有所提升；耐生物劣化性方面，抗白蟻試驗之結果顯示MF改質處理杉木之質量損失有顯著降低之情形，白蟻致死率方面於重量增加率W25及W35組亦有良好之效果，而耐腐朽性能結果亦顯示MF改質處理杉木不論以兩種褐腐菌L. sulphureua、F. pinicola及兩種白腐菌L. betulina、T. versicolor進行試驗皆能有效降低其質量損失。最後在加速耐候試驗部分，經QUV加速耐後試驗後之表面顏色變化、粗糙度及表面濕潤性評估，MF改質處理杉木相較於未處理組具較佳之耐候特性。In order to improve the self-sufficiency rate of wood in Taiwan, in recent years, the effectively harvesting and utilization of domestic wood, and actively promote the certification system of domestic wood and bamboo products are encouraged. In addition, the qualities of the domestic wood is the key to develop the further application, therefore, the first part of this research is to investigate the sawing yield and the strength grading of the China fir wood, and the allowable stress is also evaluated to improve the utilization efficiency of the wood. In order to expand its applications and improve the durability for outdoor use, the second part of this study is to investigate the selected properties including mechanical properties, dimensional stability and anti-biological degradation properties of China fir wood modified by melamine-formaldehyde resin (MF) treatment. The result showed that the sawing yield was increased with the log diameter. However, the strength properties for visual graded China fir wood revealed a large variability in Class 1 to Class 3 grade, while they were graded more precisely by the E-grading rule and the GP (Grading parameter) grading rule. Comparing with two visual graded rules, CNS 14630 (2017) and CNS 14631 (2002), the result showed that the lumber with Class 3 and below grade had the higher distribution ratio according to CNS 14631 (2002) inspection. In conclusion, the relationship between the log qualities and lumber properties showed that the higher the grade of log presented, the better the visual properties and strength of lumber were performed. On the other hand, the mechanical properties including compressive strength, hardness, shear strength and bending properties of China fir wood were increased after treated by MF. The result also revealed that the hardness of China fir wood had the highest improvement and followed by the compressive strength. On the contrary, the increments of bending properties and shear strength were not obvious. In terms of the dimensional stability of the treated China fir wood, the water absorption and volumetric swelling coefficient both decreased with the weight percent gain of the MF penetration increased, meanwhile, the anti-swelling efficiency of treated China fir wood increased. Furthermore, the result of the termite resistance test showed that the mass loss of China fir wood was reduced after treated by the MF resin, and the highly termite mortality rate was presented in the W25 and W35 groups. Furthermore, the results of decay resistance test indicated that the mass loss was also reduced for the MF treated China fir wood no matter tested by brown rot fungi (L. sulphureua, F. pinicola) or white rot fungi (L. betulina, T. versicolor). Finally, after accelerated weathering test, the China fir wood treated with MF resin had a better surface properties performance, including of surface color change, roughness and wettability than untreated one.摘要 i Abstract ii 目次 iv 表目次 vi 圖目次 ix 第一章 前言 1 第二章 文獻回顧 4 一. 杉木簡介 4 二. 影響木材材質之因素 4 三. 原木與製材品分級 5 （一）目視分等與機械等級區分 5 （二）非破壞性檢測技術 7 四. 戶外用木材之改質處理 11 （一）防腐藥劑注入改質處理 11 （二）熱處理改質技術 12 （三）樹脂改質處理 15 第三章 材料與方法 18 一、實大材 18 （一）原木與製材品品等 18 （二）實大材節面積測量 18 （三）物理性質 19 （四）非破壞性檢測試驗 20 （五）抗彎強度試驗 21 二、小試材 21 （一）三聚氰胺甲醛樹脂改質處理 22 （二）物理性質 22 （三）非破壞性檢測試驗 24 （四）機械性質 24 （五）耐生物劣化性 26 （六）加速耐候試驗 27 （七）掃描式電子顯微鏡觀察 29 三、資料分析 29 第四章 結果與討論 30 一、原木與實大材 30 （一）原木製材利用率 30 （二）實大材之基本性質 31 （三）目視等級區分與機械等級區分 33 （四）預測模型之建立與分級 45 （六）容許應力設計 52 二、MF改質處理杉木 57 （一）MF改質處理杉木之重量增加率 57 （二）機械性質 59 （三）尺寸安定性 62 （四）耐生物劣化性質 66 （五）表面顏色變化 71 （六）加速耐候試驗 72 第五章 結論 76 參考文獻 7