Abstract
Radiation-curable urethane acrylates have been extensively used and successfully implemented in industrial wood coatings thanks to their capability to provide a balance of mechanical and chemical properties. However, isocyanates, one of the main building blocks in the conventional urethane acrylates, pose toxicity and health hazards both in the manufacturing and application, and therefore, are targeted for restricted use and limited occupational exposure in the impending environmental regulations. In this regard, this study presents the development of urethane acrylate oligomers using nonisocyanate approaches and their application in industrial wood coatings. Two acrylic-functional nonisocyanate polyurethane oligomers (NIPU-ACs), NIPU-AC-2 with longer urethane chains and higher flexibility and NIPU-AC-1 with shorter urethane chains, were synthesized as main building blocks of radiation-curable wood coatings. Next, a series of 20 wood coating systems were formulated using a D-optimal mixture experimental design methodology to find the optimized quaternary mixtures composed of the two synthetic NIPU-ACs, and trimethylolpropane triacrylate (TMPTA) and dipropylene glycol diacrylate (DPGDA) as reactive diluents. The results of the study revealed that at a constant 5 wt% of TMPTA, formulations rich in NIPU-AC-2 showed higher impact resistance, scratch resistance, and pull-off adhesion, which was attributed to the flexible structure of this oligomer. On the other hand, coatings including higher contents of NIPU-AC-1, which induces higher crosslink density (XLD) to the system, demonstrated higher Tg and pendulum hardness. Evaluation of the optimal coatings not only validated the predictability of models, but also determined that the coatings have promising stain and abrasion resistance, and good thermal stability. The results show that NIPU-ACs developed in this study have excellent potential as an alternative to conventional urethane acrylates in the development of low-VOC and sustainable industrial wood coatings.
Graphic abstract

This is a preview of subscription content, access via your institution.













References
Zareanshahraki, F, Asemani, HR, Skuza, J, Mannari, V, “Synthesis of Non-isocyanate Polyurethanes and Their Application in Radiation-Curable Aerospace Coatings.” Prog. Org. Coat., 138 105394 (2020). https://doi.org/10.1016/j.porgcoat.2019.105394
Zareanshahraki, F, Mannari, V, ““Green” UV-LED Gel Nail Polishes from Bio-based Materials.” Int. J. Cosmet. Sci., 40 555–564 (2018). https://doi.org/10.1111/ics.12497
Akdogan, OK, Zareanshahraki, F, Mannari, V, “Dual-Cure Polyurethane Coatings from Soybean Oil and Their Film Properties as a Function of Cure Sequence.” J. Lipid Sci. Technol., 50 112–122 (2019)
Zareanshahraki, F, Jannesari, A, Rastegar, S, “Morphology, Optical Properties, and Curing Behavior of UV-Curable Acrylate-Siloxane Polymer Blends.” Polym. Test., 85 106412 (2020). https://doi.org/10.1016/j.polymertesting.2020.106412
Zareanshahraki, F, Davenport, A, Cramer, N, Seubert, C, Lee, E, Cassoli, M, “Durability Study of Automotive Additive Manufactured Specimens”. SAE Int. J. Adv. Curr. Prac. Mob., 2 1659–1668 (2020). https://doi.org/10.4271/2020-01-0957
Wu, Z, Tang, L, Dai, J, Qu, J, “Synthesis and Properties of Aqueous Cyclic Carbonate Dispersion and Non-isocyanate Polyurethanes Under Atmospheric Pressure.” Prog. Org. Coat., 136 105209 (2019). https://doi.org/10.1016/j.porgcoat.2019.105209
Pappas, SP, Radiation Curing: Science and Technology. Springer, Berlin (2013)
Glöckner, P, Radiation Curing: Coatings and Printing Inks; Technical Basics, Applications, and Trouble Shooting. Vincentz Network GmbH & Co KG, Hanover (2008)
Fechter, R, Gould, M, Marino, T, Mejiritski, A, Martin, D, "Radiation-Curable Coatings for Wood Substrates from Multifunctional Acrylate Oligomers", US20050245636A1, 2005. https://patents.google.com/patent/US20050245636A1/en (accessed February 5, 2019)
Ali, MA, Ooi, TL, Salmiah, A, Ishiaku, US, Ishak, ZAM, “New Polyester Acrylate Resins from Palm Oil for Wood Coating Application.” J. Appl. Polym. Sci., 79 2156–2163 (2001). https://doi.org/10.1002/1097-4628(20010321)79:12<2156::AID-APP1023>3.0.CO;2-K
Landry, V, Blanchet, P, Boivin, G, Bouffard, J-F, Vlad, M, “UV-LED Curing Efficiency of Wood Coatings.” Coatings, 5 1019–1033 (2015). https://doi.org/10.3390/coatings5041019
Modjewski, RJ, "UV Curing for Wood Applications", in TadTech report, 1999: pp. 45–48.
Tathe, DS, Jagtap, RN, “Biobased Reactive Diluent for UV-Curable Urethane Acrylate Oligomers For Wood Coating.” J. Coat. Technol. Res., 12 187–196 (2015). https://doi.org/10.1007/s11998-014-9616-5
Wang, J, Wu, H, Liu, R, Long, L, Xu, J, Chen, M, Qiu, H, “Preparation of a Fast Water-Based UV Cured Polyurethane-Acrylate Wood Coating and the Effect of Coating Amount on the Surface Properties of Oak (Quercus alba L.).” Polymers (Basel), (2019). https://doi.org/10.3390/polym11091414
Maurya, SD, Kurmvanshi, SK, Mohanty, S, Nayak, SK, “A Review on Acrylate-Terminated Urethane Oligomers and Polymers: Synthesis and Applications.” Polym.-Plast. Technol. Eng., (2017). https://doi.org/10.1080/03602559.2017.1332764
Blattmann, H, Fleischer, M, Bähr, M, Mülhaupt, R, “Isocyanate- and Phosgene-Free Routes to Polyfunctional Cyclic Carbonates and Green Polyurethanes by Fixation of Carbon Dioxide.” Macromol. Rapid Commun., 35 1238–1254 (2014). https://doi.org/10.1002/marc.201400209
Slocombe, RJ, Hardy, EE, Saunders, JH, Jenkins, RL, “Phosgene Derivatives. The Preparation of Isocyanates, Carbamyl Chlorides, and Cyanuric Acid.” J. Am. Chem. Soc., 72 1888–1891 (1950). https://doi.org/10.1021/ja01161a009
Baur, X, “Isocyanates: Occupational Exposures and Disorders.” Pneumologie, 57 526–531 (2003). https://doi.org/10.1055/s-2003-42221-1
Goossens, A, Detienne, T, Bruze, M, “Occupational Allergic Contact Dermatitis Caused by Isocyanates.” Contact Dermatitis., 47 304–308 (2002). https://doi.org/10.1034/j.1600-0536.2002.470509.x
Safety and Health Topics | Isocyanates - Evaluating Exposure | Occupational Safety and Health Administration, (n.d.). https://www.osha.gov/SLTC/isocyanates/evaluation.html (accessed January 8, 2019)
Yang, HS, Hung, PLK, "Method for Scavenging Moisture in Polyisocyanates and Formulations Thereof", WO2001077216A1, 2001. https://patents.google.com/patent/WO2001077216A1/en (accessed January 20, 2020)
Figovsky, O, Shapovalov, L, Potashnikov, R, Tzaid, Y, Bordado, J, Letnik, D, De Schijuer, A, "Foamable Photo-Polymerized Composition", US Patent 6960619, 2005
Assumption, HJ, Mathias, LJ, “Photopolymerization of Urethane Dimethacrylates Synthesized via a Non-isocyanate route.” Polymer, 44 5131–5136 (2003). https://doi.org/10.1016/S0032-3861(03)00530-5
Wang, X, Soucek, MD, “Investigation of Non-isocyanate Urethane Dimethacrylate Reactive Diluents for UV-Curable Polyurethane Coatings.” Prog. Org. Coat., 76 1057–1067 (2013). https://doi.org/10.1016/j.porgcoat.2013.03.001
Cornille, A, Michaud, G, Simon, F, Fouquay, S, Auvergne, R, Boutevin, B, Caillol, S, “Promising Mechanical and Adhesive Properties of Isocyanate-Free Poly(hydroxyl urethane).” Eur. Polym. J., 84 404–420 (2016). https://doi.org/10.1016/j.eurpolymj.2016.09.048
Kardar, P, Ebrahimi, M, Bastani, S, Jalili, M, “Using Mixture Experimental Design to Study the Effect of Multifunctional Acrylate Monomers on UV Cured Epoxy Acrylate Resins.” Prog. Org. Coat., 64 74–80 (2009). https://doi.org/10.1016/j.porgcoat.2008.07.022
Mirabedini, SM, Jamali, SS, Haghayegh, M, Sharifi, M, Mirabedini, AS, Hashemi-Nasab, R, “Application of Mixture Experimental Design to Optimize Formulation and Performance of Thermoplastic Road Markings.” Prog. Org. Coat., 75 549–559 (2012). https://doi.org/10.1016/j.porgcoat.2012.05.012
Zen, NIM, AbdGani, SS, Shamsudin, R, Masoumi, HRF, “The Use of D-Optimal Mixture Design in Optimizing Development of Okara Tablet Formulation as a Dietary Supplement.” TheScientificWorldJournal, 2015 684319 (2015). https://doi.org/10.1155/2015/684319
Isocyanate-Free Polyurethane Technology for Wood Coating Applications: Approaches to Reducing VOC in Clearcoat Formulations, American Coatings Association. (n.d.). https://www.paint.org/article/isocyanate-free-polyurethane-technology-wood-coating-applications/ (accessed January 22, 2020)
Asemani, H, Zareanshahraki, F, Mannari, V, “Design of Hybrid Non Isocyanate Polyurethane Coatings for Advanced Ambient Temperature Curing Applications.” J. Appl. Polym. Sci., 136 47266 (2019). https://doi.org/10.1002/app.47266
Carothers, WH, “Polymers and Polyfunctionality.” Trans. Faraday Soc., 32 39–49 (1936). https://doi.org/10.1039/TF9363200039
Pallant, J, SPSS Survival Manual: A Step by Step Guide to Data Analysis Using IBM Spss, 5th ed. Open Univ Pr, Maidenhead (2013)
Bardage, SL, Bjurman, J, “Adhesion of Waterborne Paints to Wood.” J. Coat. Technol., 70 39–47 (1998). https://doi.org/10.1007/BF02697810
Alinejad, M, Henry, C, Nikafshar, S, Gondaliya, A, Bagheri, S, Chen, N, Singh, SK, Hodge, DB, Nejad, M, “Lignin-Based Polyurethanes: Opportunities for Bio-Based Foams.” Elast. Coat. Adhes. Polym., 11 1202 (2019). https://doi.org/10.3390/polym11071202
Jones, FN, Organic Coatings: Science and Technology, Fourth; 4, p. 2017. John Wiley, Hoboken (1936)
Roose, P, Fallais, I, Vandermiers, C, Olivier, M-G, Poelman, M, “Radiation Curing Technology: An Attractive Technology for Metal Coating.” Prog. Org. Coat., 64 163–170 (2009). https://doi.org/10.1016/j.porgcoat.2008.08.020
Fink-Jensen, P, “Hardness Testing of Organic Coatings.” Pure Appl. Chem., 10 239–292 (1965). https://doi.org/10.1351/pac196510030239
Drazinakis, GE, Lechwar, A, "Critical Study on Scratch Resistance Test Methods", (2014) 12.
Perkins, WG, “Polymer Toughness and Impact Resistance.” Polym. Eng. Sci., 39 2445–2460 (1999). https://doi.org/10.1002/pen.11632
Baek, YH, Chung, MK, Son, SM, Song, EH, Shin, CS, Baek, KK, Reliability on Coating Pull-Off Adhesion Strength Test, in Nace Corrosion 2009 Conference and Expo, Nace International, 2009: p. 10
Jian, Y, He, Y, Jiang, T, Li, C, Yang, W, Nie, J, “Volume Shrinkage of UV-Curable Coating Formulation Investigated by Real-Time Laser Reflection Method.” J. Coat. Technol. Res., 10 231–237 (2013). https://doi.org/10.1007/s11998-012-9446-2
Chattopadhyay, DK, Webster, DC, “Thermal Stability and Flame Retardancy of Polyurethanes.” Prog. Polym. Sci., 34 1068–1133 (2009). https://doi.org/10.1016/j.progpolymsci.2009.06.002
More, AS, Lebarbé, T, Maisonneuve, L, Gadenne, B, Alfos, C, Cramail, H, “Novel Fatty Acid-Based Di-isocyanates Towards the Synthesis of Thermoplastic Polyurethanes.” Eur. Polym. J., 49 823–833 (2013). https://doi.org/10.1016/j.eurpolymj.2012.12.013
Karami, Z, Kabiri, K, Zohuriaan-Mehr, MJ, “Non-isocyanate Polyurethane Thermoset Based on a Bio-resourced Star-shaped Epoxy Macromonomer in Comparison with a Cyclocarbonate Fossil-based Epoxy Resin: A Preliminary Study on Thermo-mechanical and Antibacterial Properties.” J. CO2 Util., 34 558–567 (2019). https://doi.org/10.1016/j.jcou.2019.08.009
Acknowledgments
The authors would like to thank Robert Roggers, Hamid Mortazavian, and Micheal Czaplicki at L&L Products, MI, USA, for their technical support including conducting the GPC studies. They also extend their thanks to Dr. Gregg Wilmes and Ehsan Zarshenas, at the Chemistry department at Eastern Michigan University, for helping with performing and analyzing the 1HNMR spectroscopy.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Appendix 1
Appendix 1
“Appendix 1” presents the detailed statistical treatment and ANOVA for the models developed by the Design-Expert software for each of the properties as a function of compositional variables. The figure numbers mentioned here refer to the figures in the manuscript.
A: Effect of coating composition on the solvent resistance of the cured coatings
The data in Fig. 5 are fitted with a quadratic model, with statistical measures for interactions of the variables as summarized in Table 9. The Model F-value of 12.68 implies the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. Values of “Prob > F” less than 0.0500 indicate model terms are significant. Values greater than 0.1000 indicate the model terms are not significant. Thus, the interactions between A and B are not significant. The “Lack of Fit F-value” of 0.71 implies the Lack of Fit is not significant relative to the pure error. There is a 66.17% chance that a “Lack of Fit F-value” this large could occur due to noise. Other statistics of interest include: Std. Dev. = 14.49, R2 = 0.9022, Mean = 181.25, Adj R2 = 0.8310, C.V.% = 7.99, Pred. R2 = 0.3975. The final equation in terms of pseudo-components is:
The final equation in terms of real components is:
B: Effect of coating composition on T g of the cured coatings
The data were fitted with a reduced quadratic model, as shown in Table 10. The Model F-value of 24.40 implies that the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. In this case, A, C, BC, BD, CD are significant model terms. The “Lack of Fit F-value” of 5.05 implies the Lack of Fit is not significant relative to the pure error. There is a 4.55% chance that a “Lack of Fit F-value” this large could occur due to noise. Other statistics of interest include: Std. Dev. = 4.35, R2 = 0.9185, Mean = 49.10, Adj R2 = 0.8808, C.V.% = 8.86. The final equation in terms of pseudo-components is:
The final equation in terms of real components is:
C: Effect of coating composition on pendulum hardness of the cured coatings
ANOVA showed that the best model to fit the correlation between the composition and pendulum hardness was a linear mixture model and the statistical measures for interactions of the variables are given in Table 11. The Model F-value of 18.12 implies that the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. The “Lack of Fit F-value” of 0.95 implies the Lack of Fit is not significant relative to the pure error. There is a 56.52% chance that a “Lack of Fit F-value” this large could occur due to noise. Other important statistics are: Std. Dev. = 9.70, R2 = 0.7726, Mean = 80.55, Adj R2 = 0.7299, C.V.% = 12.04, Pred. R2 = 0.6294. The final equation in terms of pseudo-components is:
Final equation in terms of real components is:
D: Effect of coating composition on Pencil Hardness of the cured coatings
The Model F-value of 8.04 implies the model is significant. There is only a 0.16% chance that an F-value this large could occur due to noise. In this case, A, B, D, AB, AD, BD, CD are significant model terms. The “Lack of Fit F-value” of 1.17 implies the Lack of Fit is not significant relative to the pure error (Table 12). There is a 43.26% chance that a “Lack of Fit F-value” this large could occur due to noise. Other statistics of interest include: Std. Dev. = 0.33, R2 = 0.8786, Mean = 4.45, Adj R2 = 0.7693, C.V.% = 7.41, Pred. R2 = 0.3276. The final equation in terms of pseudo-components is:
The final equation in terms of real components is:
E: Effect of coating composition on Impact Reistance of the cured coatings
The impact resistance data was fitted with a special cubic model, with statistical measures for interactions of the variables as summarized in Table 13. The Model F-value of 245.77 implies the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. B, D, AB, AC, AD, BC, BD, CD, ABC, ACD, BCD are significant model terms. The “Lack of Fit F-value” of 0.39 implies the Lack of Fit is not significant relative to the pure error. There is a 55.75% chance that a “Lack of Fit F-value” this large could occur due to noise. Other statistics of interest include: Std. Dev. = 3.00, R-Squared = 0.9981, Mean = 61.00, Adj R2 = 0.9941, C.V.% = 4.92. The final equation in terms of pseudo-components is:
The final equation in terms of real components is:
F: Effect of coating composition on Pull-Off Adhesion strength of the cured coatings
The pull-off adhesion data were fitted with a special cubic model, with statistical measures for interactions of the variables as summarized in Table 14. The Model F-value of 9.78 implies the model is significant. There is only a 0.07% chance that an F-value this large could occur due to noise. AB, AC, AD, BC, BD are significant model terms. The “Lack of Fit F-value” of 1.74 implies the Lack of Fit is not significant relative to the pure error. There is a 27.91% chance that a “Lack of Fit F-value” this large could occur due to noise. Other statistics of interest include: Std. Dev. = 24.34, R-Squared = 0.8979, Mean = 421.82, Adj R2 = 0.8061, C.V.% = 5.77, and Pred. R2 = 0.6180. The final equation in terms of pseudo-components is:
The final equation in terms of actual components is:
Rights and permissions
About this article
Cite this article
Zareanshahraki, F., Mannari, V. Formulation and optimization of radiation-curable nonisocyanate polyurethane wood coatings by mixture experimental design. J Coat Technol Res 18, 695–715 (2021). https://doi.org/10.1007/s11998-020-00453-x
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11998-020-00453-x