Pengxu Qi – POLYNT
INTRODUZIONE
Polyurethane coatings are the standard for wood flooring and furniture applications, due to their fast return-to-service, tailored performance properties, and adaptability to ever-changing market needs. 1 Since the introduction of polyurethane technologies, technical advancements and regulatory pressures have driven innovations. In response to tightening regulations on volatile organic compounds (VOC), high-VOC solvent-borne systems have been gradually replaced by lower-VOC alternatives. 2 However, developing eco-friendly solutions that retain performance remains a challenge. 3
Waterborne polyurethane technologies have emerged as the leading solution to meet stringent regulations without sacrificing the performance. However, conventional non-oil modified waterborne PUDs, although suitable for light-duty flooring applications, often fail under more demanding environments, such as heavy foot traffic.
The thermoplastic nature of the polymer contributes to insufficient marring, abrasion, and chemical resistance. To address these shortcomings, oil-modified PUDs were developed, incorporating bio-based unsaturated fatty acids. The inherent oxidative crosslinking capability facilitates the formation of robust covalent networks, enhancing film performance.
Urethane coatings for wood applications use either aromatic or aliphatic isocyanates to achieve desired properties. Aromatic systems, such as toluene diisocyanate, offer rapid property development and high hardness at the expense of flexibility, whereas aliphatic isocyanates, isophorone diisocyanate, for instance, excel in providing superior flexibility but develop properties more slowly. Striking a balance between these opposing characteristics presents a persistent roadblock.
Polynt’s Urotuf® F110-D1W-31 represents a breakthrough in waterborne polyurethane technology, combining the best of both aromatic and aliphatic systems. This paper overviews its performance across six key performance metrics, benchmarking it against two commercially available aliphatic and aromatic waterborne oil-modified PUDs to demonstrate its exceptional capabilities.
BENCHMARKING AND TESTING
Drying performance significantly influences the usability and application efficiency of a coating. Urotuf® F110-D1W-31 achieves a tack-free state under a 500-gram weight within an hour, matching aromatic benchmarks and surpassing aliphatic alternatives, which requires over two hours. In addition to surface-cure, a qualitative fingernail gouging test revealed rapid through-cure development within five hours, comparable to aromatic benchmarks. This ensures resistance to basic wear and enabling faster return-to-service (Fig. 1).
Hardness, critical for resisting surface damage under mechanical stress, was assessed using König Pendulum Hardness (ASTM D4366) and Sward Hardness (ASTM D2134) tests. The new resin consistently outperforms aliphatic benchmarks while matching or exceeding aromatic counterparts. After 7 days of curing, it achieves over 150 seconds for König Hardness and 70 oscillations for Sward Hardness (Fig. 2). Notably, Urotuf® F110-D1W-31 surpasses all four commercial benchmarks in both hardness metrics after 24 hours, reaffirming its rapid curing and property development capabilities.
The flexibility and mechanical durability of coatings are studied through both Impact Resistance Test (ASTM D2794) and Mandrel Bending Test (ASTM D522). The new resin excels in both tests, enduring a 1/8-inch mandrel bending and 160 lbs•inches of impact without cracking.
This unique combination of superior flexibility and exceptional hardness makes it ideal for demanding applications like gym floors.
Chemical resistance is vital for coatings exposed to harsh chemicals. Chemical resistance test (ASTM D1308) was performed with common household chemicals over a 4-hour period. Urotuf® F110-D1W-31 outperforms other competitors, scoring 5 in over 80% of cases and highest on average (Fig. 3).
Its superior resistance ensures lasting aesthetics and surface projection in challenging environments like kitchens. Mar and abrasion resistance determine the longevity of coatings in abrasive environments. In Taber Abrasion Resistance Test (ASTM D4060-14), Urotuf® F110-D1W-31 demonstrated minimal material loss of 56 mg after 1000 cycles, far exceeding aromatic benchmarks (147 and 113 mg) while slightly beating aliphatic ones (63 mg and 70 mg). Additionally, its mar resistance developed rapidly, reaching full effectiveness within 24 hours, compared to 72 hours for aromatic benchmarks. These results underscore the resin’s outstanding mar and abrasion resistance, leveraging advanced aliphatic OMU technology to excel in challenging environments.
CONCLUSIONS
Urotuf® F110-D1W-31 represents a breakthrough in waterborne polyurethane technology, combining the rapid curing and hardness of aromatic systems with the flexibility and abrasion resistance of aliphatic systems (Fig. 4). Its exceptional durability makes it especially suited for applications requiring high standards of protection.
NOTES:
1 Das, A., and Mahanwar, P. “A Brief Discussion on Advances in Polyurethane Applications”. Advanced Industrial and Engineering Polymer Research, 3.3 (2020): 93-101.
2 Noble, K.L. “Waterborne polyurethanes.” Progress in Organic Coatings, 32.1-4 (1997): 131-136.
3 Yang, S., Cooley, S., and Albrecht, A. “Vegetable Oil-Based Urethanes for Wood Coatings”. Paint & Coatings Industry Magazines, October 6th, 2017.
