PU樹脂預處理對針葉樹中小徑木物理與塗裝性質之影響

Effects of Polyurethane Pretreatment on the Physical and Finishing Performances of Medium and Small Diameter Softwood

盧崑宗(Kun-Tsung Lu) ； 林詩翎(Shih-Ling Lin)

《林產工業》 25卷1期 (2006/03) Pp. 29-40

https://doi.org/10.6561/FPI.2006.25(1).4

摘要

本研究係以短油性萞麻油變性醇酸樹脂等為主劑，分別與芳香族聚異氧酸酯PTDI、PMDI及脂肪族聚異氰酸酯PIPDI、PHDI等4種硬化劑，依NCO/(OH+COOH)=1.2莫耳比調配成聚胺基甲酸酯（PU）樹脂，將國產針葉樹材之杉木、柳杉及台灣杉等中小徑木表面預處理，分析PU樹脂處理對中小徑木表面均質性與尺寸安定性等物理性質之影響，及PU樹脂處理材以硝化纖維素（NC）拉卡塗裝後之性能改善效益。試驗結果顯示，PU樹脂可於木材表面固化成膜，並能提升木材表面硬度及均質性，更可增加木材之抗吸濕效能（MEE）及抗膨潤效能（ASE），進而改善木材尺寸安定性，其中又以含芳香族聚異氰酸酯PMDI（S-PMDI）處理者為最佳。又經PU樹脂處理之木材，明度降低、彩度增加、色相偏紅，賦予更佳的鮮豔性及厚重感。PU處理材塗裝後之塗膜硬度、附著性及冷熱循環耐久性等性質均可獲得改善，其中又以僅噴塗一道NC面漆者較經二道二度底漆再噴塗一道面漆者塗裝性能更佳，但塗膜耐光性質則較未經PU處理者為差。

關鍵字

針葉樹中小徑木 ； 聚異氰酸酯 ； 聚胺基甲酸酯 ； 預處理 ； 物理與塗裝性能

並列摘要

The objective of this study is to analyze the improvement of surface homogeneity dimensional stability and finishing performance of domestic medium and small diameter softwoods pretreated by polyurethane (PU) resins. The two-components PU resins were prepared from combined short oil type of castor oil-modified alkyd resins as a polyol with four kinds of polyisocyanates including aromatic hardener (PTDI and PMDI) and aliphatic hardeners (PIPDI and PHDI), respectively, by the molar ratio of NCO/OH+COOH of 1.2. Three kinds of wood, about a diameter 10~15 cm including Cunninghamia lanceolata, Taiwania cryptomerioidies, and Cryptomeria japonica were supplied by Hui-Sun Forest Station, were used. The nitrocellulose (NC) lacquer including sanding sealer and top clear were also used in this study. The results indicated that the surface hardness, homogeneity, moisture excluding efficiency (MEE) and antiswelling efficiency (ASE) of softwood pretreated with PU resins were enhanced and among all of the PU resins, the one containing PMDI was the best for wood treatment. A vivid and massive feeling of PU treated wood, which will be appealing to most people, were also obtained. To investigate finishing performance of wood, two kinds of finishing procedure i.e. NC lacquer sanding sealer→top clear and top clear only on PU treated wood were examined. The results revealed that the hardness, adhesion, and durability of films on the PU treated wood were superior to those of untreated one, especially for top clear finishing only. While, the light fastness of film on PU treated wood was inferior to untreated one.

並列關鍵字

Medium and small diameter softwood ； Polyisocyanate ； Polyurethane ； Pretreatment ； Physical and finishing performance