Research Article Preparation and Characterization of UV-Curable Cyclohexanone-Formaldehyde Resin and Its Cured Film Properties Guang Yang, 1 Hongqiang Li, 1 Xuejun Lai, 1 Yi Wang, 1 Yifu Zhang, 2 and Xingrong Zeng 1 1 College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China 2 Yueyang Intech Synthetic Material Co., Ltd., Yueyang 414009, China Correspondence should be addressed to Hongqiang Li; hqli1979@gmail.com and Xingrong Zeng; psxrzeng@gmail.com Received 11 July 2014; Revised 29 September 2014; Accepted 22 October 2014; Published 11 November 2014 Academic Editor: Jose Ramon Leiza Copyright © 2014 Guang Yang et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. UV-curable cyclohexanone-formaldehyde (UVCF) resin was prepared with cyclohexanone-formaldehyde (CF) resin, isophorone diisocyanate (IPDI), and pentaerythritol triacrylate (PETA) as base substance, bridging agent, and functional monomer, respectively. Te structure of UVCF was characterized by Fourier transform infrared spectroscopy (FT-IR), 1 H-nuclear magnetic resonance spectroscopy ( 1 H-NMR), and gel permeation chromatography (GPC). Te viscosity and photopolymerization behavior of the UV-curable formulations were studied. Te thermal stability and mechanical properties of the cured flms were also investigated. Te results showed that UVCF resin was successfully prepared, the number of average molecular weight was about 2010, and its molecular weight distribution index was 2.8. With the increase of UVCF resin content, the viscosity of the UV- curable formulations increased. Afer exposure to UV irradiation for 230 s, the photopolymerization conversion of the UV-curable formulations was above 80%. Moreover, when the UVCF content was 60%, the formulations had high photopolymerization rate, and the cured UVCF flms showed good thermal stability and mechanical properties. 1. Introduction Ketone-aldehyde (KA) resin, an important resins synthesized with ketone and aldehyde, is well known as multifunctional additives in coatings and inks [1, 2]. Owing to the existence of carbonyl and hydroxyl groups, in the molecular structure, KA resin has good compatibility with coating or ink resins, and can be used as dispersant for pigments in the coatings and inks [3–5]. Meanwhile, KA resin can endow the products with high hardness and good adhesion to various substrates. In addition, the saturated chain in KA resin made contributions to the high gloss of the coating flm [6, 7]. Terefore, the preparation of KA resin and its application in coatings and inks have been paid more and more attentions [8–10]. Zhang et al. synthesized the urea-isobutyraldehyde-form- aldehyde (UIF) resins by the condensation of urea, isobu- tyraldehyde, and formaldehyde. Te results showed that the UIF resins had good yellowing resistance, UV resistance, and solubility in common organic solvents [11]. A new melamine-formaldehyde-butanone (MFB) resin was pre- pared by Glowacz-Czerwonka and Kucharski [12], and they found that the coatings with MFB resin had transparent appearance, high hardness, and good resistance against boil- ing water. Nowadays, due to its advantages of fast curing rate, energy saving, and environment protection, UV-curing has been considered to be one of the most promising technologies [13– 15]. For example, compared to traditional thermal-curable coatings, UV-curable coatings always show better compre- hensive performance such as excellent flm-forming property and high thermal stability. However, most of the KA resins have no C=C double bonds to react with UV-curable resin and it is easily to migrate from the UV-curable coatings, which will lead to the decrease of the mechanical properties and solvent-resistant properties [16]. Terefore, it is necessary to introduce the curable groups into the structure of KA resin for UV-curing. Mishra et al. [17] prepared a radiation- curable resin through modifying the carbonyl-hydrogenated Hindawi Publishing Corporation International Journal of Polymer Science Volume 2014, Article ID 890930, 8 pages http://dx.doi.org/10.1155/2014/890930