Abstract Epoxy acrylate resins modified by polyurethane with excellent mechanical properties play a crucial role in UV-curable coatings, but the high viscosity limits their further applications in 3D printing, electronic packaging material. In this work, a series of polyurethane modified epoxy acrylate resins containing various e-caprolactone unit content were successfully synthesized to reduce the viscosity of polyurethane modified epoxy acrylate resins. The chemical structure and molecular weight of the prepared resins were characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR) and gel permeation chromatography (GPC), respectively. The influences of e-caprolactone unit on the viscosity of resins and double bond conversion of cured films were studied. The dynamic thermomechanical properties, mechanical properties, thermal stability and basic properties of UV curable coatings were also evaluated. The results show that the viscosity of resins is reduced by two orders of magnitude. As the e-caprolactone unit content increased, the adhesive force increased from 0B to 5B according to ASTM D3359, while the glass transition temperatures (Tg) of films and pencil hardness were slightly lower than those of the conventional polyurethane modified epoxy acrylate resins. In summary the introduction of e-caprolactone unit in the side chain enables the preparation of polyurethane modified epoxy acrylate resin with ultralow viscosity as well as a more comprehensive adhesive and impact force performance.

中文翻译：

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含有ε-己内酯单元的聚氨酯改性环氧丙烯酸酯树脂

摘要 聚氨酯改性环氧丙烯酸树脂具有优异的机械性能，在紫外光固化涂料中发挥着至关重要的作用，但其高粘度限制了其在3D打印、电子封装材料等方面的进一步应用。在这项工作中，成功地合成了一系列含有各种ε-己内酯单元含量的聚氨酯改性环氧丙烯酸酯树脂，以降低聚氨酯改性环氧丙烯酸酯树脂的粘度。所制备树脂的化学结构和分子量分别通过傅里叶变换红外光谱（FTIR）、质子核磁共振光谱（1H NMR）和凝胶渗透色谱（GPC）表征。研究了ε-己内酯单元对树脂粘度和固化膜双键转化率的影响。还评估了UV固化涂料的动态热机械性能、机械性能、热稳定性和基本性能。结果表明，树脂的粘度降低了两个数量级。随着ε-己内酯单元含量的增加，根据ASTM D3359，粘合力从0B增加到5B，而薄膜的玻璃化转变温度（Tg）和铅笔硬度略低于常规聚氨酯改性环氧丙烯酸酯树脂。综上所述，通过在侧链中引入ε-己内酯单元，可以制备出具有超低粘度以及更全面的粘合和冲击力性能的聚氨酯改性环氧丙烯酸酯树脂。还评估了紫外线固化涂料的热稳定性和基本性能。结果表明，树脂的粘度降低了两个数量级。随着ε-己内酯单元含量的增加，根据ASTM D3359，粘合力从0B增加到5B，而薄膜的玻璃化转变温度（Tg）和铅笔硬度略低于常规聚氨酯改性环氧丙烯酸酯树脂。综上所述，通过在侧链中引入ε-己内酯单元，可以制备出具有超低粘度以及更全面的粘合和冲击力性能的聚氨酯改性环氧丙烯酸酯树脂。还评估了紫外线固化涂料的热稳定性和基本性能。结果表明，树脂的粘度降低了两个数量级。随着ε-己内酯单元含量的增加，根据ASTM D3359，粘合力从0B增加到5B，而薄膜的玻璃化转变温度（Tg）和铅笔硬度略低于常规聚氨酯改性环氧丙烯酸酯树脂。综上所述，通过在侧链中引入ε-己内酯单元，可以制备出具有超低粘度以及更全面的粘合和冲击力性能的聚氨酯改性环氧丙烯酸酯树脂。根据ASTM D3359，粘合力从0B增加到5B，而薄膜的玻璃化转变温度（Tg）和铅笔硬度略低于常规聚氨酯改性环氧丙烯酸酯树脂。综上所述，通过在侧链中引入ε-己内酯单元，可以制备出具有超低粘度以及更全面的粘合和冲击力性能的聚氨酯改性环氧丙烯酸酯树脂。根据ASTM D3359，粘合力从0B增加到5B，而薄膜的玻璃化转变温度（Tg）和铅笔硬度略低于常规聚氨酯改性环氧丙烯酸酯树脂。综上所述，通过在侧链中引入ε-己内酯单元，可以制备出具有超低粘度以及更全面的粘合和冲击力性能的聚氨酯改性环氧丙烯酸酯树脂。