An evaluation of the catechol lipid compositions of natural lacquer materials and their correlation with the physicochemical properties of lacquer films have become important issues for the advancement of natural lacquer technologies. Here, a convenient method for evaluating the relative composition of urushiol and laccol catechol lipids in natural lacquers using Fourier transform infrared (FT-IR) analysis is proposed. Urushiol and laccol exhibited different characteristic peaks in the FT-IR spectrum owing to the different stereoisomer structures of the conjugated dienes, and the peak positions linearly shifted according to the relative content of the urushiol and laccol components in the natural lacquers. This evaluation method was applicable for estimating the mixing compositions of laccol and urushiol in commercially available natural lacquer products. A quantitative analysis of the physicochemical properties of various lacquer films with urushiol, laccol, and their mixtures confirmed that the hardening speed, mechanical hardness, adhesion, and corrosion resistance deteriorated, whereas the transparency and haze properties improved as the laccol content increased. This study suggests that the estimation and optimization of laccol and urushiol compositions in natural lacquers are an important strategy for improving the physicochemical properties of natural lacquer films and extending their applications in various functional coatings.

天然漆材料中邻苯二酚脂质成分的评估及其与漆膜理化性质的相关性已成为天然漆技术发展的重要问题。在此，提出了一种利用傅立叶变换红外光谱（FT-IR）分析天然漆中的漆酚和漆酚邻苯二酚脂质相对组成的简便方法。由于共轭二烯的立体异构体结构不同，漆酚和漆酚在FT-IR光谱中表现出不同的特征峰，并且峰位置根据天然漆中漆酚和漆醇组分的相对含量线性变化。该评估方法适用于评估市售天然漆产品中漆酚和漆酚的混合组成。对含有漆酚，漆酚及其混合物的各种漆膜的理化性质进行的定量分析证实，硬化速度，机械硬度，附着力和耐腐蚀性降低，而透明度和雾度随着漆酚含量的增加而提高。这项研究表明，估计和优化天然漆中漆酚和漆酚的组成是改善天然漆膜的理化性质并扩展其在各种功能涂料中的重要策略。它们的混合物证实硬化速度，机械硬度，粘合性和耐腐蚀性降低，而透明度和雾度随着漆酚含量的增加而改善。这项研究表明，估计和优化天然漆中漆酚和漆酚的组成是改善天然漆膜的理化性质并扩展其在各种功能涂料中的重要策略。它们的混合物证实硬化速度，机械硬度，粘合性和耐腐蚀性降低，而透明度和雾度随着漆酚含量的增加而改善。这项研究表明，估计和优化天然漆中漆酚和漆酚的组成是改善天然漆膜的理化性质并扩展其在各种功能涂料中的重要策略。