梳型紫外光快速固化聚氨酯的制备及涂层性能

梳型紫外光快速固化聚氨酯的制备及涂层

性能

朱亚丽,董运生,陈丽杰,姚有为,洪阳阳,唐国翌*

(清华大学 深圳研究生院 能源与环境学部,广东 深圳518055)

摘要:以1,3-丙二醇、甲基丙烯酸缩水甘油酯为主要原料,无水四氯化锡为催化剂,三氟乙酸为助催化剂,合成了一种具有光化学活性的聚醚(PGMA)。此聚醚以碳氧键为主链,以甲基丙烯酸酯基为梳型侧链,端基为羟基。将上述具有光化学活性的聚醚(PMGA)与异佛尔酮二异氰酸酯(IPDI)反应,制得具有光化学活性的聚氨酯〔Poly(PGMA-IPDI)〕。在上述聚氨酯中加入活性稀释剂和光引发剂,制备出一种能够快速光固化的树脂,固化时间可以达到1s,柔韧性达到0.5mm、附着力为最高级0级,同时固化涂层在盐溶液、水溶液、碱溶液中浸泡无脱落,在酸性水溶液中脱落时间也达到36h,涂层具有优异的性能。 关键词:紫外光固化;聚醚;阳离子聚合;聚氨酯树脂

中图分类号:TQ314 文献标识码:A

Synthesis of the Comb-like Rapid UV-cured Polyurethane and

Its Film Properties

ZHU Yali, DONG Yunsheng, CHENG Lijie, YAO Youwei, HONG Yangyang, TANG Guoyi*

(Division of Environment & Energy, Graduate School at Shenzhen, Tsinghua University, Shenzhen

518055,Guangdong,China)

Abstract: The study developed an efficient method for the synthesis of a novel photosensitive polyether via cationic ring-opening polymerization of glycidyl methacrylate using 1,3-propanediol as a precursor, and tin tetrachloride and trifluoroacetic acid as catalysts. The hydroxyl-terminated polyether (PGMA) contains comb-like methacrylate groups as its side chains. Then, new polyurethane acrylate (poly(PGMA-IPDI)) was prepared by the reaction of PGMA and isophorone diisocyanate (IPDI). Meanwhile, the targeted structure of PGMA and poly(PGMA-IPDI) was confirmed by FT-IR and 1H NMR. The UV-curable coatings were prepared by the incorporation of poly(PGMA-IPDI) oligomers into formulations together with reactive diluents and photoinitiators, which exhibited excellent properties such as curing speed, flexibility and chemical-solvent

resistance. Remarkably, the UV-curable coatings could cured by exposure to ultraviolet radiation in just one second. Meanwhile, the UV-curable coatings not only have no peel off from sheet iron within 48h in solvent resistant experiments, but also remained unchange for 36h in acidic aqueous solution.

Key words: UV-cured; polyether; cationic polymerization; polyurethane Foundation item:International Cooperation Research Project(GJHZ20150316160614839) 基金项目:国际合作研究项目(批准号:GJHZ20150316160614839)

作者简介:朱亚丽(1991-),女,硕士生。联系人:唐国翌(1954-),男,教授,电话:13530478111,E-mail:tanggy@sz.tsinghua.edu.cn。

紫外光固化技术兴起于20世纪60年代,与传统热固化技术相比,它具有低能耗、低固化温度、低VOC(挥发性有机物)排放量、高固化速率和高效率等优良特性,被广泛应用于清漆、涂料、胶黏剂、光学材料、印刷油墨和电路板等领域中

[1-2]

。聚氨酯丙烯酸酯(PUA)

作为紫外光(UV)固化材料中被大量使用的低聚物种类之一,其兼具聚氨酯(PU)和丙烯酸酯的优点,具有优良的耐刮擦性能、光学性能、粘结性能、耐候性等

[5]

[6]

[3-4]

。但聚氨酯丙烯

酸酯的固化时间较长,极大地限制了其在紫外光固化上的应用,为了适应现代工业生产对快速成型技术的要求,尤其是3D打印技术对光固化时间的要求,如何提高紫外光固化体系的固化速度,降低紫外光固化体系的固化时间,已成为该领域的热点问题之一。

紫外光固化树脂体系,一般由低聚物(主体树脂)、光引发剂、活性稀释剂以及其他助剂等组成。为了提高紫外光固化树脂的固化速度,人们已经进行了很多研究,例如:添加混合型光引发剂、制备光热混杂固化体系、开发新型活性稀释剂、改变光固化树脂各组分的比例等。但鲜见通过改变主体树脂的结构来提高紫外光固化速度的报道,部分对低聚物结构改进的报道

[7-9]

,主要是与改善机械性能相关。然而,低聚物作为紫外光固化树脂中最重要的

组分,其对紫外光固化体系的固化速率起决定性作用。为了提高聚氨酯类紫外光固化树脂的固化速度,本研究从主体树脂的改性出发,首先以1,3-丙二醇和甲基丙烯酸缩水甘油酯为原料,合成了具有光敏特性的端羟基聚醚。再用上述端羟基聚醚和二异氰酸酯缩聚,合成光敏聚氨酯。然后,将光敏聚氨酯、活性稀释剂、光引发剂等按比例配制,得到具有快速固化特性的紫外光固化树脂,并对固化后的漆膜性能进行了测定。合成路线图1所示:

1—GMA;2—PGMA;3—IPDI;4—Poly(PGMA-IPDI)

图1 光敏树脂的合成路线

Fig. 1 The synthetic route of the photosensitive polyurethane acrylate

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