Influence of Tinuvin 292 on Chlorinated Rubber Varnish/ Coating Properties under UV Radiation

This article presents the effect of Tinuvin 292 (a light stabilizer based on liquid hindered amine) on properties of chlorinated rubber varnish/coating under 100 UV-thermo-humidity complex cycles. The properties included relative hardness, adhesion, flexural strength, impact resistance, and gloss loss. The results showed that 2.5 weight percent (wt%) of Tinuvin 292 had much improved physical properties of varnish coating such as relative hardness, adhesion, flexural strength, impact resistance, and gloss loss. Fourier-transform infrared spectroscopy (FT-IR),Thermogravimetric analysis (TGA), and Field Emission Scanning Electron Microscopy (FESEM) were used to evaluate the changes of aged coatings in comparison to the initial ones. FT-IR spectrums also showed that intensities of CH2 and C=O (ester) groups changed strongly or slightly depending on the appearance of Tinuvin 292. SEM images indicated that the surface of aged coating with Tinuvin 292 was smoother than coating without Tinuvin 292. TGA also expressed that thermal oxidation stability of chlorinated rubber varnish/ coating had been enhanced with 2.5 wt% of Tinuvin 292.