Screen printing of uv curable polyurethane acrylate binder prepared with different pigment concentrations on synthetic leather and gloss and hardness properties of printed films

In this paper, UV curing technology and screen printing method were firstly together applied on synthetic leather, in order to determine the gloss and hardness values of screen printed UV curable polyurethane acrylate binder films prepared with different pigment concentrations. UV curable water-borne pigmented formulations were prepared with different pigment concentration (3%, 5% and 7%) and two types of photoinitiators (Omnirad® 500 and Omnirad® 819 DW). The curing process were conducted under different combinations of lamps (Ga, Hg, GaHg and GaGaHg) at three power levels. Pendulum hardness and gloss values of printed films were investigated. In gloss measurements, higher gloss values were obtained at the pigment concentration of 3% at all lamp combinations. Moreover, the highest gloss value (20.96) of the sample printed with 3% pigment concentration was obtained at GaHg lamp combination at 679 mJ/cm2 energy density. The higher hardness values were obtained at a pigment concentration of 3% at all lamp combinations. The highest hardness value (9.8) of the pigmented polymeric films with 3% pigment concentration was obtained at GaGaHg lamp combination at 966 and 1663 mJ/cm2 energy densities. The results show that high gloss and hardness values can be achieved at lower pigment concentration of 3%. Considering energy efficiency, curing under the GaHg lamp combination at an energy intensity of 679 mJ/cm2 can be recommended for synthetic leather samples, which are printed with low pigment concentration (3%).