基材與塗料種類對透明塗裝木材光變色之影響

Influence of Different Wood Species and Coatings on Photo-Discoloration of Clear Coated Wood

張惠婷(Hui-Ting Chang) ； 張上鎮(Shang-Tzen Chang)

《林產工業》 16卷1期 (1997/03) Pp. 38-47

摘要

透明塗裝木材在使用一段時間後，表面會產生明顯的黃化，其主要原因係由於塗膜本身的變色，以及光線穿過塗膜而抵至木材界面後，造成木材的光變色，故使塗裝木材顏色黃化。本試驗之目的為分析透明塗裝木材之光黃化，除了評估常用透明塗料及基材種類對透明塗裝木材光變色之影響外，亦評估三類光安定劑對透明塗裝木材耐光性之影響。試驗結果顯示常用之透明塗料中，以脂肪族聚胺基甲酸醋塗料塗裝木材之耐光性較好。基材種類對透明塗裝木材的光變色有很大的影響力，紅柳桉、紅櫟木等深色木材經透明塗裝後，光黃化的程度較輕微，耐光性較佳。至於光安定劑種類對透明塗裝木材耐光性之影響，以紫外光吸收劑（Tinuvin-1130）的改善效果較佳，而自由基捕捉劑與抗氧化劑之改善效果並不顯著。

關鍵字

透明塗料 ； 木材 ； 光變色 ； 耐光性 ； 光安定劑 ； 紫外光吸收劑

並列摘要

Photoyellowing was readily observed on wood surfaces coated with clear coatings. Owing to the UV light could penetrate through the clear film and reach the interface of wood and clear coating, the discoloration of clear coated wood was attributed to the yellowing of both clear coating film and wood underneath the clear coating. Therefore, the objectives of this study are (1) to evaluate the lightfastness of several kinds of clear coatings, (2) to investigate the influence of wood species on the photodiscoloration of clear coated woods, (3) to find an effective light stabilizer which could inhibit the photodegradation of coated wood. The experimental results reveal that the lightfastness of aliphatic polyurethane coating is better than others. The lightfastness of the dark-colored wood such as red lauan and red oak is superior to the others. The tendency of photoyellowing of these clear coated woods is similar to uncoated wood. It is generally accepted that using a suitable light stabilizer to inhibit the photoyellowing of clear coatings is necessary. The results obtained from the color variation demonstrate that 2% Tinuvin-1130 UVabsorber, among the light stabilizers examined, is the most effective one to improve the lightfastness of clear coated woods.

並列關鍵字

Clear coating ； wood ； photodiscoloration ； lightfastness ； light stabilizer ； UV absorber