水性树脂

水性树脂是使用水而不是有机溶剂作为介质的聚合物,通常包含所有以水为主要载体的树脂,其可以是水溶性的、或分散在水中[1][2]。水性树脂常用于涂料、粘合剂、密封剂、弹性体和复合材料[3][4]

发展

大多数涂料有四种基本成分—树脂、溶剂、颜料和添加剂,但主要成分是树脂[5]。随著许多国家建立环境保护法规以及石化原料供应问题,促使越来越多化学家及企业转向开发水性涂料技术,并且由于树脂/聚合物是涂料中最重要的部分。 水通常是一种低成本(但不是免费)的商品,供应充足,没有毒性问题.因此以水作为载体来生产油漆、油墨、粘合剂和纺织品施胶剂等的需求一直存在。1960 年代以美国为首开始,水性涂料的用量开始增长,其理由是:1) 降低涂料的可燃性(安全因素); 2) 减少排放到大气中的挥发性有机物; 3) 成本[6],以上都有助于减少对石油衍生溶剂的依赖。近年来,从立法层面导致的开发压力导致了水性树脂越来越受到关注。[7][8][9]

水性树脂种类

水性环氧树脂

环氧树脂系统一般由固化剂和环氧树脂组成,固化剂和环氧树脂都可以制成水性的。以助溶剂和表面活性剂的乳化的水性环氧树脂(分子量 >1000)分散乳液很容易可从市场取得。环氧树脂主链经常被修饰增加亲水性以确保乳化性。

干燥过程中,树脂颗粒随著溶剂挥发凝结聚集成膜,为了固化树脂并使其交联,通常添加胺基固化剂,称为双组分系统[10]

水性聚氨酯

水性聚氨酯系指分散在水中的聚胺酯树酯,分为阴离子、阳离子、非离子型,其中以阴离子型最为常见[11]。水性聚氨酯借由引入亲水基团使树脂能被分散在水中,但亲水性基团会导致制成之成品防水性不佳,研究者们正在针对此问题进行开发研究[12],如引入聚二甲基矽氧烷等结构[13]。水性聚氨酯也有二组份版本,由于二组分聚氨酯由多元醇与异氰酸酯及水与异氰酸酯反应固化,因此需要特殊的配方跟合成技术[14][15],例如利用磺酸盐改质异氰酸酯[16]

参见

  1. ^ Bicak, Niyazi; Gazi, Mustafa; Karagoz, Bunyamin. New water-soluble polymer with allyl pendant groups. Designed Monomers and Polymers. 2006-01-01, 9 (2): 193–200. S2CID 101639021. doi:10.1163/156855506776382646. 
  2. ^ Waterborne Resins. Allnex. [2020-03-24]. (原始内容存档于2020-03-25). 
  3. ^ Padget, John. Polymers for waterbased coatings - A Systematic Overview. JCT Journal of Coatings Technology. 1994, 66 (839): 89–105. 
  4. ^ Annable, T; Brown, R A; Padget, J C; van den Elshout, A. Improvements in the application properties of water-based low VOC coatings. Surface Coatings International. July 1998, 81 (7): 321–329. ISSN 1356-0751. S2CID 59152908. doi:10.1007/bf02700556. 
  5. ^ Waterborne coatings and additives. Karsa, D. R., Davies, W. D., Royal Society of Chemistry (Great Britain), Society of Chemical Industry (Great Britain). Cambridge, UK: Royal Society of Chemistry. 1995. ISBN 0-85404-740-9. OCLC 33164476. 
  6. ^ Jackson, K. Recent advances in water-borne protective coatings. Surface Coatings International. 1999-07-01, 82 (7): 340–343. ISSN 1356-0751. S2CID 135613088. doi:10.1007/BF02720130 (英语). 
  7. ^ Thames S.F. “Conversion to Water-Soluble/Water-borne polymers” February 1996 Lecture notes from the University of Southern Mississippi  short course
  8. ^ Waterborne Industrial Coatings: Evolving Perceptions and Technologies. www.coatingstech-digital.org. [2021-07-22]. (原始内容存档于2022-01-28) (英语). 
  9. ^ CoatingsTech - Waterborne Direct-to-Metal Coatings: Enduring Solutions in Corrosion Protection. www.coatingstech-digital.org. [2022-07-07] (英语). 
  10. ^ Richardson F.B “Water-borne Epoxy Coatings: Past, Present and Future”    Modern Paints and Coatings April 1988 pages 84-88
  11. ^ Water Based Polyurethanes Dispersions(PUDs)-An Overview. www.linkedin.com. [2020-03-24]. (原始内容存档于2018-11-10) (英语). 
  12. ^ Xu, Liangfeng. CO2 triggered hydrophobic/hydrophilic switchable waterborne polyurethane-acrylate with simultaneously improved water resistance and mechanical properties. Journal of Coatings Technology and Research (American Coatings Association). July 2021, 18 (4): 989–998. ISSN 1547-0091. S2CID 233176697. doi:10.1007/s11998-021-00476-y. 
  13. ^ He, Xiaoling; He, Jingwei; Sun, Yangkun; Zhou, Xiaopei; Zhang, Jingying; Liu, Fang. Preparation and characterization of cationic waterborne polyurethanes containing a star-branched polydimethylsiloxane. Journal of Coatings Technology and Research. 2022-07-01, 19 (4): 1055–1066. ISSN 1935-3804. doi:10.1007/s11998-021-00584-9 (英语). 
  14. ^ EP 2523987,Nachshon-Galili, Nitsa & Reut Sussan,“Two-component water-based polyurethane compositions and coatings”,发表于2012-11-21 
  15. ^ The Case for Two-Component Waterborne Polyurethane Coatings. www.pcimag.com. [2020-03-25]. (原始内容存档于2020-03-25) (英语). 
  16. ^ Peng, Zhongkang. Synthesis and properties of water-dispersible polyisocyanates carrying sulfonate. J. Coat. Technol. Res. 2020, 17 (2): 345–359. S2CID 207989601. doi:10.1007/s11998-019-00277-4. 

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