无溶剂柔韧环氧树脂在金属表面烤漆中的应用性能测试

Property Evaluation of Solvent-Free Flexible Epoxy Resins in Metal Surface Coating

通过选择含柔韧聚氨酯链段的特殊环氧树脂及含柔韧聚醚链段的脂肪胺固化剂,按优化的比例配制涂料,样品在180~230℃烘烤后能达到较高硬度(>2H),在冲击后无裂纹、皱纹及剥落等现象,对铝金属表面显示很强的附着力,并显示较佳的耐弯折性能。涂膜在沸水中都没有出现明显的起泡、起皱、开裂、脱落等现象,只在经过冲击后的薄弱处出现局部开裂、脱落或起泡。各项实验结果显示,含聚氨酯柔韧链段的环氧树脂具有较佳的综合性能,而且本实验采用的制备聚氨酯-环氧树脂共聚物的方法较其他环氧树脂的增韧方法简便直接。涂料采用的环氧树脂和固化剂双组分体系在室温下具有足够的工作时间、但在高温烘烤时能在5~10min内达到充分固化。在具有催化作用的固化剂存在时,涂料在200℃的固化时间可以缩短至2min以内。

By selecting special epoxy resins containing flexible polyurethane segments and aliphatic amine curing agents containing polyether segments, the coating materials exhibit high hardness (pencil hardness >2H) after baking at 180-230 ℃. The coating samples show no cracking, wrinkling and peeling after impact testing. The coating materials have high adhere on the metals such as aluminum. Coating samples containing polyurethane segments in epoxy resins exhibit better anti-bending properties. In boiling water, the coating samples show no obvious blister, wrinkling, cracking and shedding, and only show local damage in samples with weakened areas after impact testing. All experimental data show better overall properties from the urethane -containing epoxy systems, achieved from a simpler and more straight -forward method to form urethane -epoxy copolymers than other epoxy toughening methods. The two-component coating systems with epoxy resins and curing agents possess adequate workable time at room temperature, but can be sufficiently cured within 5-10 minutes under baking condition. Furthermore, in the presence of catalytic curing agent, the cure time can be shortened to 2 minutes at 200 ℃.