UV-Curable Coatings

In ultraviolet-cured systems, UV radiation is used to initiate polymerization. The reaction generated by UV rays enables a liquid system to transform into a solid system with rubber-like or glassy properties at room temperature within seconds. Coatings passed through a speed-adjustable conveyor equipped with UV lamps undergo cross-linking within seconds and convert into a fully hardened structure. In UV-curable systems, all reactive components participate in the reaction and become part of the polymer network structure. These coating formulations contain no solvent. Their compositions include oligomers, photoinitiators, monomers (for cross-linking), fillers and various additives. Regarding the advantages of UV-cured coatings, we can highlight the following: rapid formation of cross-linked structures enabling fast production (thereby increasing stackability), low investment and production costs, absence of volatile organic solvents harmful to the environment and health in their formulations, applicability at room temperature, and a wide range of applications.

They are preferred in many sectors such as the wood and furniture industry, automotive industry and electronics sector.

The basic components forming protective coating formulations prepared with UV radiation are reactive oligomers, monomers (reactive diluents) and photoinitiators.

At the same time, additives (rheology agents, antifoams, dispersants, surface modifiers, etc.) are added to impart different properties to the coating, and fillers (in pigmented systems) are also added to reduce cost. Reactive oligomers are the most important element determining the physical properties of UV-cured coatings. They are low-molecular-weight unsaturated polymers and generally contain unsaturated acrylic groups attached to the ends of the molecule or pendant to the polymer chain. Reactive diluents, which remain bonded within the polymer structure during the reaction and also affect the physical, chemical and mechanical properties of the coatings, are called "monomers". The reactive diluents used are classified into two main groups: monofunctional and polyfunctional monomers. Monofunctional monomers are generally used to reduce the viscosity of the oligomer. Rough formulations for 100% solids, solvent-free UV coatings and water-based UV coatings can be recommended as follows. The products offered by BASF, for which we serve as distributors, for UV-cured systems are oligomers called base resins, monomers which are reactive diluents, and additives specific to UV systems. BASF offers an extensive product portfolio under the name "Laromer®" as oligomers and monomers depending on the application and system. As oligomers, all resin types are available including epoxy acrylates, polyester acrylates, polyether acrylates, urethane and water-based acrylates, as well as unsaturated polyesters. As functional monomers: PPTTA (pentaerythritol tetraacrylate), TMPEOTA (trimethylolpropane triacrylate), GPTA (glycerol triacrylate), TMPTA (trimethylolpropane triacrylate), HDDA (hexanediol diacrylate), TPGDA (tripropylene glycol diacrylate), DPGDA (dipropylene glycol diacrylate), POEA (phenol oxyethyl acrylate), TBCH (t-butyl cyclohexyl monoacrylate) structures allow reactive diluents to adjust the viscosity of the coating and impart properties such as hardness or flexibility to the coating. Monomers affect the durability and flexibility of the resulting film, while also wetting the applied surface well, increasing film adhesion and gloss. As Boysan Boya San. ve Tic. A.Ş., we are pleased to offer you the Laromer® resins and monomers produced by BASF, for which we serve as representatives in Turkey and Turkic republics, whose performance is trusted and which are UV-cured. Tuğba Sadıç - Technical Director - Boysan Boya A.Ş.