Study On The Blue Light Curing System Of Free Radical-cationic Hybrid Photopolymerization For Textile Digital Functional Finishing

Textile functional finishing is an effective method to endow textiles with a specific functionality and create additional value. However, the functional finishing technology commonly uses padding and curing methods, which suffer from some issues on water and energy consumption and the waste of raw materials. In this study, a new hypothesis of blue light curing for textile digital functional finishing was put forward by combining the mechanism of the visible light curing reaction and the inject method of the digital printing. In the blue light curable textile digital functional finishing, blue light photoinitiator,monomers,oligomers and functional substances were imposed on demand on the surface of the fabrics, and then free radical-cationic hybrid photopolymerization was induced by blue light irradiation to form a tough film in situ on the fabric surface, achieving an expected coating for finishing agents. The development of the blue light initiated free radical-cationic hybrid curing system is an effective way to improve the blue light curing efficiency, solve the oxygen inhibition phenomenon and enhance the substrate adhesion. Studies on blue light induced free radical-cationic hybrid initiating system and polymerization system will partly lay the theoretical foundation of the combination of textile dyeing and finishing with blue light curing for textile digital functional finishing。Firstly, the parameters optimization of the CQ/EDB/DPI three-component hybrid photoinitiating system indicated that, a high efficient free radical and cationic photopolymerization and the improvement of the oxygen inhibition could be achieved with the optimized three-component photoinitiating system(DPI:CQ:EDB=2:1:0.5(wt%)) under 80 m W/cm2 blue light irradiation.Secondly, the rheological analysis of the free radical-cationic hybrid polymerization system demonstrated that, the addition of cationic monomer UVR and epoxycyclohexane can effectively reduce the viscosity of PUA/HEA system, and further improve the mobility of the hybrid polymerization system during the digital processing. Meanwhile,studies on the physical andmechanical properties of the blue light curing free radical-cationic hybrid films showed that the blue light curing hybrid film with low initial Yang’s modulus, higher breaking strength and elongation at break was obtained based on the following formulation: PUA/HEA=60/40 wt%,20% UVR. The physical and mechanical properties of free radical-cationic hybrid film basically met the requirements of the textiles wearability.Thirdly, studies on digital anti-UV finishing on cotton fabrics using blue light curing system of free radical-cationic hybrid polymerization showed that the UPF value of the finished cotton fabrics reached 50 and the transmittance of UVA and UVB was low, presenting an excellent UV resistance and good rubbing and washing durability. Meanwhile, compared to the treated cotton fabrics with radical system, the fabric strength and durability of rubbing and washing of the treated cotton fabrics using free radical-cationic hybrid system got slightly enhanced, but there was no difference in handle.