Introduction
UV curing technology, which cures coatings within seconds under ultraviolet (UV) light, is highly efficient, environmentally friendly, and solvent-free. Waterborne UV coatings have emerged as a significant advancement, combining eco-friendliness and ease of application. This article explores the progress and innovation in waterborne UV curing resins and their applications in various industries.
Key Developments
1. Epoxy Acrylate/Polyurethane Acrylate Hybrid Systems
UV curing resins primarily consist of photoreactive oligomers, which determine the basic properties of the cured resins. Each type of base resin has its advantages and drawbacks. For instance, epoxy resins offer high hardness, excellent adhesion, gloss, and chemical resistance but lack flexibility. Conversely, polyurethane resins provide superior abrasion and scratch resistance but have limited weatherability. Researchers have developed hybrid systems combining these resins to leverage their strengths and minimize their weaknesses.
2. Dendritic or Hyperbranched Systems
Waterborne UV-curable dendritic or hyperbranched oligomers are new polymer structures with spherical or branched configurations. These polymers exhibit low entanglement between molecular chains, high reactivity, and improved solubility. Hyperbranched oligomers, with their numerous active end groups, offer low viscosity and excellent solubility, making them ideal for waterborne UV-curable resin applications.
3. Epoxidized Soybean Oil Acrylate
Epoxidized soybean oil is cost-effective and environmentally friendly, with a long molecular chain and moderate crosslinking density, enhancing the flexibility and adhesion of coatings. Recent advancements in UV-curable coatings using epoxidized soybean oil acrylate have shown promising results. For example, Ebercy860 by CUB Company in the USA has achieved commercial success. The typical synthesis method involves esterification of epoxidized soybean oil with acrylic acid.
Prospects of Waterborne UV-Curable Resins
Waterborne UV-curable resins rapidly crosslink and cure under UV light and photoinitiators. The main advantages include controllable viscosity, cleanliness, environmental friendliness, energy efficiency, and high performance. However, challenges such as long-term stability of water dispersion systems and water absorption of cured films remain. Future research will focus on:
1. Developing New Oligomers: Including low-viscosity, high-activity, high-solids, multifunctional, and hyperbranched oligomers.
2. Innovating Active Dilutants: Introducing new acrylic dilutants with high conversion rates, high reactivity, and low shrinkage.
3. Exploring New Curing Systems: Addressing incomplete curing issues due to limited UV penetration by employing dual curing systems like free radical/cationic, free radical/thermal, and free radical/anaerobic curing.
Conclusion
Waterborne UV-curable resins represent a significant step forward in creating sustainable, efficient, and high-performance coatings. Continued innovation in this field will expand the application scope and enhance the overall performance of UV-curable materials.
Post time: Aug-13-2024
