Enhancing the Flame Retardancy of UV Curable Polyurethane Acrylate Coated Films with Alumina Trihydrate Filling

Abstract

In this study, the flame retardancy of ultra violet (UV) curable polyurethane acrylate (PU) coated films were enhanced. For this aim, alumina trihydrate (ATH) filling material was mixed with the pastes including a photoinitiator and a UV curable PU. ATH filling ratio was preciously adjusted to obtain a uniform coating. The coated films were cured with a UV curing system equipped with gallium (Ga) and mercury (Hg) lamps. The chemical changes and the curing degree of the UV cured films were examined by a Fourier Transform Infrared Spectrum (FTIR) and a pendulum hardness tester. The thermal properties of the UV cured films were evaluated using a Differential Scanning Calorimeter (DSC). Moreover, vertical flammability and limiting oxygen index (LOI) measurements were conducted in order to determine the burning behavior of the UV cured films. The successful curing of the films was evidenced by means of FTIR results. The addition of ATH slightly increased the hardness values of the films. DSC results showed that ATH addition not only increased the enthalpy values but also enhanced the flame retardant property of the coated films and maximum LOI was achieved as 31.5%.