PCL-TIO2 Nanocomposite to Improve Ageing of Offset Prints

UV radiation or sunlight can affectthe printed sample by fading the ink surface and therefore the product losses it's decorative purpose and becomes less desirable to the customer. To create the efficient protective coating,titaniumdioxide(TiO2)will be used as a well-knowncompound that should lower the effects of UV radiation. TiO2should lower the colour fade after UV radiation and this will be determined by densitometric and colorimetric (CIE L*a*b*)measurements. In addition, measurement of print gloss will also be conducted to evaluate visual appearance of the sample. Biopolymer Polycaprolactone (PCL) wasthe base of the PCL-TiO2composite in which TiO2nanosized.To determine influence of the amount of TiO2, threecomposites were prepared by adding different weight ratioof the TiO2.The prepared nanocomposites were thenapplied onto the offset prints on gloss art print paper and on the uncoated paper.The results have shown that TiO2coating does affect ink’s density, colorimetric properties and print gloss after initialcoating.The change in chroma due to the accelerated ageing is most visible on yellowink, cyan and magentaproved to be the morestable. Accelerated ageing caused change in the L* of black. On all colours, increase of the TiO2weight ratio improved resistance of colour to change. Coated gloss paper was more resistant to density change where uncoated had lower change in chroma. It could be concluded that TiO2has the ability to protect the prints in the measured time interval but it has to be noted that concentration of the TiO2particles also causes colour difference and must be observed when definingcomposureof the nanocomposite.
Nanocomposite, offset, coating, biopolymer, PCL, TiO2