Urushiol-based UV-cured Wood Coatings

• Main Authors: Meng-Chi Chao, 趙孟琪
• Other Authors: Kun-Tsung Lu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/c4kmwx

碩士 === 國立中興大學 === 森林學系所 === 107 === The aims of this study were to investigate the synthesis of acrylated epoxy urushiol (AEU) by urushiol, which is the main compound of oriental lacquer, and to formulate the UV coatings and dual-cured coatings with AEU to examine the feasibility for wood coatings. In the first step, urushiol was extracted from oriental lacquer by acetone and reacted with epichlorohydrin to obtain epoxy urushiol (EU), and then, EU reacted with acrylic acid to obtain acrylated epoxy urushiol (AEU) with acryloyl group for developing free radical polymerization UV coatings. Furthermore, according to the formula of the best UV coating by adding with driers and polymeric isocyanates to prepare UV curing and oxidation polymerization for UV/Air dual-cured coatings and UV/PU dual-cured coatings, respectively. The results indicated that the UV coating formatted with pentaerythritol triacrylate (PETA) monomer of 30 phr, and photoinitiator 2,2-Dimethoxy-2-phenylacetophenone (Irgacure651) of 3 phr had the best film properties such as hardness, abrasion resistance, tensile strength, heat resistance and gloss, while its adhesion, impact resistance and bending resistance must be improved. Moreover, the film properties, such as hardness, mass retention(Solvent:acetone), bending resistance and tensile strength of UV/Air dual-cured coatings were better than those of UV coatings without metal driers. In addition, UV/Air dual-cured coatings by UV curing had better hardness, mass retention, gloss retention and alcohol resistance of films than those by air curing. Furthermore, UV/Air dual-cured coatings with metal driers of Co2+/Zr2+/Ca2+ of 0.6 phr separately and total of 1.8 phr (dual-Air-1.8), had better drying, adhesion and lightfastness than dual-Air-3.0 with total metal driers of 3.0 phr. The UV/Air dual-cured coating films by air curing also possessed excellent bending resistance. Additionally, UV/PU dual-cured coatings had better film properties than the pure UV coatings without polymeric isocyanate. The UV/PU dual-cured coating with polymeric toluene diisocyanate (pTDI) by UV curing, had better hardness, mass retention, tensile strength, gloss retention, and acetone resistance than the one with polymeric hexamethylene diisocyanate (pHDI). Moreover, both of UV/PU dual-cured coatings with different polymeric isocyanates had the excellent adhesion and bending resistance by curing at room temperature. Except the adhesion and bending resistance, among the UV/PU dual-cured coatings with the same polymeric isocyanates, the one by UV curing had the superior film properties than the one by curing at room temperature.