环氧改性聚氨酯光固化涂料研究

采用甲苯二异氰酸酯(TDI)、聚乙二醇(PEG)、二羟甲基丙酸(DMPA)和环氧树脂合成了环氧改性水性聚氨酯乳液。该乳液由于含有不饱和双键而具有感光性能,故可用作水性紫外光固化涂料或胶粘剂的预聚物。探讨了环氧丙烯酸酯(EB)和亲水扩链剂(DMPA)的添加量对涂料和涂膜性能的影响以及光引发剂用量、中和度对光固化涂料转化率的影响。结果表明,随着EB用量的增大,涂膜的硬度、耐水性、耐溶剂性及力学性能增强,但乳液外观和稳定性变差,故适宜的环氧树脂添加量为10%;随着DMPA用量的增加,涂膜硬度、强度提高,而断裂伸长率降低,耐水性变差,故DMPA用量在6%～8%范围为宜;光固化转化率随着中和度的提高而加快,适宜的引发剂用量为3%。本品的缺点是耐汽油性不够理想。

Study on epoxy modified polyurethane UV-cured coating

A waterborne polyurethane emulsion modified by epoxy resin was prepared using toluene diisocyanate (TDI), polyethylene glycol (PEG), bis(hydroxymethyl)propionic acid (DMPA) and epoxy resin. The emulsion has a photosensitivity due to unsaturated double bonds, therefore, it can be used as a prepolymer of UV-curable waterborne coatings or adhesives. The influence of the dosage of epoxy acrylate (EB) and hydrophilic chain-extending agent DMPA on performance of the coating material and film, and the dosage of UV-initiator and neutralization degree on UV-curing conversion rate was discussed. The results showed that the hardness, water resistance, solvent resistance and mechanical properties of the film were increased with increasing the amount of EB, while the appearance and the stability of the emulsion deteriorate. A suitable amount of epoxy resin is 10%; the hardness and strength of the film are enhanced while the rupture elongation and water resistance decreased with increasing dosage of DMPA. A suitable dosage range of DMPA is 6%-8%. UV-curing conversion is accelerated with increasing neutralization degree, and a suitable dosage of initiator is 3%. The disadvantage of the product is its poor gasoline resistance.