Water-based polyurethane acrylate coatings have many favourable properties such as ease of use and resistance to stains and wear and tear. They form hydrogen bonds between urethane bonds and molecular chains due to functional acrylic groups, and this provides coatings with suitable mechanical properties, resistance to extreme weather and solvents, and good appearance on wood materials.
The functionality and molecular structure can be modified to serve the needs of different wood products - cabinets, furniture, laboratory and office equipment. Water-borne polyurethane acrylate compounds emit little to no volatile organic compounds (VOCs), are inexpensive as well as eco-friendly.
Some properties of water-borne coatings are sub-par when compared to solvent-based coatings, such as gloss, slow drying rate and low hardness and to expand their application into other segments, UV curing technology is used in the manufacture of water-based coatings for fast curing. Films formed during UV-polyurethane dual-cured coating display better adhesion, impact resistance, tensile strength, lightfastness and elongation at break when compared with traditional polyurethane and UV coatings. Wood coatings based on water-borne UV light curing polyurethane-acrylates are fast-curing (around 22 minutes), whereas regular water-borne wood coatings have a drying speed of around 35 minutes.
Coatings cured with UV radiation utilise high energy UV lights sources, which form coating films by self-polymerisation. UV-curable resins consist of multifunctional acrylate monomers and oligomers associated with an aromatic ketone that is formed upon UV-exposure free radicals which will start crosslinking polymerisation. UV light curing polyurethane-acrylate coatings have good adhesion to wood, as one surface is similar to wood morphology.
As the amount of coating increases, the hardness, gloss and adhesion properties of the surface increases to different extents. When a small amount of coating is used, the coating thickness is thin and the substrate will not be sufficiently covered. Higher amounts of coating result in better coating properties. However, an excessive amount of coating, defects due to drying may occur, such as bubbling and wrinkle formation.
Research has shown that epoxy acrylate oligomer based dual cured coatings can be used as finishings for wood products. C&E offers eco-friendly and durable UV-Curable Oligomers and Monomers which are well qualified for wood coatings. We create excellence by manufacturing high-performance products that meet the requirements of modern applications and satisfy customer expectations.
By Ashni Arun on April 21st, 2022