Water and Oil Repellent Finishing of Textiles by UV Curing the color differences are lower on Ole- ophobol compared to Pymasil. It was true also if the products were applied by thermal process. The dispersion of values was similar but for Pymasil the values were generally higher. Moreover for Pymasil there was also some influ- ence of the product add-on, with a col- or difference higher if the add-on was higher. This parameter was unaffect- ing for Oleophobol. The concentration of the finishing agent was the less influencing parameter on the final samples. As expected, best results were found with lower product concentrations, while the final color was affected increasing this concen- tration. As previously, it was not con- firmed for Oleophobol, that was unaf- fected by the product concentration. Irradiance The best results were obtained on sam- ples treated with the higher irradiance, improved even with respect to those thermally treated. The worst results, that is the most evident color differ- ence after the treatment, were obtained on samples radiated with the lower UV irradiance. The most important effect was revealed on VIS fabric. Aging Tests The stability upon aging of the photo- grafting treatment was checked. Re- sistance to aging was tested by mea- suring the contact angle on 20 g/L Ole- ophobol-treated samples, two years after the surface treatment. The sam- ples were stored in the laboratory at room temperature in the dark. The com- parison of CA with water and oil be- tween freshly prepared samples and aged samples is reported in Figure 8 for all the fabrics and irradiance val- ues. The aged samples were still found hy- drophobic, with an average 15% reduc- tion of the water contact angle regard- less the irradiance. Moreover, the aged samples were still found oil repellent, but an average 40% reduction of the oil contact angles was measured. The worst results were obtained on VIS,while on COT fabrics the decrease was lower. The partial loss of oil repellency can be due Coatings 2017, 7, 60 10 of 12 to a rearrangement and orientation toward the inner part of the fibers of the surface fluorine chains, occurred during this time and mainly ascribable to some moisture content [23].aging time samples (two years) UV treated with Oleophobol showed only a low hydrophobicity decrease com- pared to fresh samples, while the loss of oil repellency was higher. Neverthe- less, aged samples, particularly cot- ton, can still be considered oil repel- lent. ConclusionsIn conclusion, UV curing appears to be a valid alternative to the finishing thermal process actually applied at in- dustrial level. By UV curing, in fact, same or even better water and oil re- pellency than thermal process were obtained, applying a low amount of fin- ishing agent. It enables the better main- tenance of textile properties coupled with the low process temperature, with a clear economic advantage.In this work, various textile fabrics were coated with silicone and fluoro- carbon-based resins by photo-curing using ultraviolet irradiation. A semi-in- dustrial scale-up of the process was carried out: A great number (about 180) of large fabric samples were padded with Oleophobol or Pymasil finishing agents and then were irradiated in air by UV light with tunable irradiance. Samples were exposed to radiation on one side for 60 s. The add-on of vari- ous finishing agents was kept low to reduce the treatment cost. White and dyed samples of different textile com- position were treated and evaluated in terms of conferred repellency, yellow- ing, or color changes. The most rele- vant process parameters were investi- gated, considering the thermal process normally adopted at industrial level as reference. The results were statistical- ly evaluated by ANOVA with Minitab 16 software, to point out the most in- fluencing parameters and the real pos- sibility of replacing the thermal treat- ment with UV. Water and oil drop absorption times higher than 120 min were found on all Oleophobol-treated samples, showing that Oleophobol works very well as oil and water repellent agent for textiles. UV process was revealed to work bet- ter than the thermal one, in fact higher water and oil contact angles were ob- tained with a lower amount (1% o.w.f.) of finishing agent. Considering the UV process, best results were yielded by white fabrics, rather than dyed, and medium values of both irradiance and product concentration, taking into ac- count both contact angles and color reflectance evaluations. Finally, contact angle measurements carried out on long NCM-APRIL 2020 74Among UV treated samples, the type and color of treated fabrics had great influence on the obtained results, in particular for Pymasil; the best results were obtained by lowering the product concentration, while a negligible effect was due to different irradiance values. Finally, UV light caused lower yellow- ing compared to thermal treatment, with appreciable values just on viscose at higher radiation doses, due to the light- ness of the fabric. Obtained results were considered en- couraging and can open the way for a real application of the UV process to industrial field. Supplementary Materials: The follow- ing are available online at http:// www.mdpi.com/2079-6412/7/5/60/s1. Table S1: Correspondence between Minitab codes and process parameters for the plots of Figures from S1 to S8. Figure S1: Matrix Plot on average val- ues of water and oil CA on Oleophobol- treated samples by UV radiation, Fig- ure S2: Interaction Plot for water CA on Oleophobol-treated samples, Figure S3: Interaction Plot for oil CA on Ole- ophobol-treated samples, Figure S4: Main effect plot for water CA on Ole- ophobol-treated samples, Figure S5: Main effect plot for oil CA on Ole- ophobol-treated samples, Figure S6: Interaction plot for water CA on Pyma-