桐油為基質自由基聚合型UV塗料之合成與應用

Synthesis and Applications of Tung Oil-based Free Radical Polymerization UV coatings

本研究係將桐油先與甘油行酯交換反應形成甘油酯後，再與多異氰酸酯（PTDI）與甲基丙烯酸-2-羥乙基酯（HEMA）反應合成壓克力化胺酯寡聚體，將其與反應性單體依重量比80／20混合，再添加對全量樹脂液重量3%之光引發劑（Irgacure 651）調配成自由基聚合型之UV塗料，探討單官能性甲基丙烯酸甲酯（MMA）、雙官能性二丙烯酸1, 6-己二醇酯（HDDA）及三官能性三羥甲醇丙烷三丙烯酸酯（TMPTA）等單體種類對塗料與塗膜性質之影響，並分析此型塗料應用於木材塗裝之可行性。試驗結果發現，桐油與甘油之酯交換反應溫度設定為190℃時，才可穩定地得到甘油酯，而壓克力化胺酯寡聚體合成時需5h緩慢滴入甘油酯，才能使反應完全。又自由基聚合型UV塗料硬化性佳，塗膜機械強度優良且富含光澤，其中又以反應性單體為TMPTA者，塗膜性質硬度及拉伸強度最佳，其他物性亦較為均衡，但應用於木材塗料上，其塗膜附著性與耐久性仍需進一步加以改善。 Tung oil-based acrylated urethane oilgomers for free radical polymerization UV coatings were synthesized by reacting glyceride with polyiscyanate (PTDI) and 2-Hydroxyethyl methacrylate (HEMA). The glycerides were obtained by transesterification of tung oil and glycerin. The UV coating formulations were based on the weight ratio of oligomer/monomer of 80/20, and in conjunction with 3% photoinitiator (Irgacure 651) by the weight ratio of total resins. The effect of the functionality of monomers such as mono-functional methyl methacrylate (MMA), di-functional 1,6-hexanediol diacrylate (HDDA), and tri-functional trimethylolpropane triacrylate (TMPTA) on the properties of UV coatings and its feasibility for wood finishing were examined. The results indicated that the adequate temperature was at 190℃ for transesterification reaction, and the reaction time of glyceride for preparing acrylated urethane oilgomers was at least 5 h and the glyceride should slowly be added to the reactant mixture drop by drop. The UV coatings had an excellent curing behavior, and superior mechanical properties and gloss of film. Among the UV coatings, the one containing TMPTA had the best hardness, tensile strength, and a balance effect on the properties of coating and films. However, the poor adhesion and durability of this UV coating must further be improved for wood coating application.

Tung oil-based acrylated urethane oilgomers for free radical polymerization UV coatings were synthesized by reacting glyceride with polyiscyanate (PTDI) and 2-Hydroxyethyl methacrylate (HEMA). The glycerides were obtained by transesterification of tung oil and glycerin. The UV coating formulations were based on the weight ratio of oligomer/monomer of 80/20, and in conjunction with 3% photoinitiator (Irgacure 651) by the weight ratio of total resins. The effect of the functionality of monomers such as mono-functional methyl methacrylate (MMA), di-functional 1,6-hexanediol diacrylate (HDDA), and tri-functional trimethylolpropane triacrylate (TMPTA) on the properties of UV coatings and its feasibility for wood finishing were examined. The results indicated that the adequate temperature was at 190℃ for transesterification reaction, and the reaction time of glyceride for preparing acrylated urethane oilgomers was at least 5 h and the glyceride should slowly be added to the reactant mixture drop by drop. The UV coatings had an excellent curing behavior, and superior mechanical properties and gloss of film. Among the UV coatings, the one containing TMPTA had the best hardness, tensile strength, and a balance effect on the properties of coating and films. However, the poor adhesion and durability of this UV coating must further be improved for wood coating application.