Functional and Energy Efficient Textile Coating Systems

Functional and Energy Efficient Textile Coating Systems F. Terzioglu, E. Rohleder, M. Rabe Research Institute for Textile and Clothing (FTB), Hochschule Niederrhein

Content I. Conventional textile coatings vs. UV coatings UV curing vs. thermal curing UV coating technology I. Research Projects Development of textile coatings based on UV curing Development of energy and resource efficient NIR sensitized textile coating systems

Introduction Motivation for new technologies in the field of textile coating make textiles more suitable save energy and time accentuate or inhibit natural characteristics improving standard wet processes impart new characteristics water-free technologies increase life time and durability

Conventional textile coatings textile coatings are generally solvent based or aqueous crosslinking induced by thermal energy

UV coatings 100%-systems radiation-curable coatings based on acrylates crosslinking by radical or cationic polymerization

UV coatings aqueous dispersions radiation-curable coatings based on acrylates crosslinking by radical or cationic polymerization

UV curing vs. thermal curing (Source: Dr. Hönle AG)

Requirements for UV coatings UV/NIR coating reactive C=C UV radiation bondenergy dh 613 kj/mol = 201 nm energy UV A C = 200nm 380nm photoinitiators

Light sources Lamps LEDs Lasers

Photoinitiators

UV initiated radical polymerization + + UV/NIR radiation resin photoinitiator radicals initiation polymerization propagation cured film termination

Formulation for UV coatings resin/oligomer monomer (reactive diluent or water) photoinitiator additives film properties scratch resistance abrasion resistance elasticity reactivity viscostiy crosslink density reactivity UV-dose levelling deaeration gloss degree thickener (for waterb.) function chemicals

Chemical background

Research projects 1. Development of new energy saving textile finishing methods for technical applications, based on UV curing 2. Photoinitiators for resource efficient and energy saving polymerzations The projects were funded by German Federal Ministry of Economics and Technology (BMWi) via Zentrales Innovationsprogramm Mittelstand (ZIM), under grant number KF 2914003BN2 and KF 2233809MF3.

NIR-coating-system NIR-radiation well known as thermal energy source also usable for sensitized photopolymerization processes initiator system consists of two components sensitizer = absorbing component coinitiator = generates radicals

Sources NIR LED arrays I mission suitable to pment of more different uding UV, visible small range of emission suitable to the sensitizer low intensity requires development of more intensive LEDs in different wavelengths including UV, visible and NIR

NIR-LED arrays II atmospheric curing process with 6 LEDs solubilty problems of the coinitiator => solution = three roll mill oxygen inhibition results in non completely cured surface => solution = inertisation

NIR-LED arrays III experimental setup with an inertbox coating with a wire-bar applicator purging with nitrogen curing with 6 NIR-LED arrays good curing in depth and surface good reactivity FT-IR analysis shows a conversion of 84% C=C

NIR Laser laser: 808 nm, focus 0.6 mm, 135 W high energy output = shrinking and melting less energy output = no surface curing curing between glassplates => good (70%)

UV vs. NIR UV high sensitivity established curing system problematic with pigments or light stabilizers harmful UV light requires safety light shielding NIR less sensitive than UV systems unknown to coating-technology yellow, red and blue pigmented coatings curing of layers upto several mm in just one step NIR light uncritical in handling

Summary + reduced energy consumption and environmental impact + fast drying/curing + no solvents (VOC) + high production speeds + little space required + low equipment cost + suitable for themosensitive fibres + high chemical and mechanical resistant ozone generation (only for UV; not for NIR) monomers/oligomers expensive chemicals

Acknowledgement We wish to thank A. Joßen, C. Schmitz, M. Schläpfer, T. Brömme, B. Strehmel, for their work and ideas promoting these research results. Contact Research Institute for Textile and Clothing (FTB) Hochschule Niederrhein Webschulstraße 31 41065 Mönchengladbach H8, Booth A116 Fikret Terzioglu Tel.: +49 2161 186 6029 fikret.terzioglu@hs-niederrhein.de