Fabrication of fluoride-free water repellency cotton fabrics with water-borne polyurethane/acrylate dispersion

In this work, a new fluoride-free awaterborne polyurethane (WPUA) water repellent agent was synthesized and used for cotton fabrics with the concerns of environmental and human safety. Specifically, the WPUA was prepared by isophorone diisocyanate (IPDI), poly(tetrahydrofuran) (PTMG), 2,2-bis(hydroxymethyl)butyric acid (DMBA), and 2-hydroxyethyl acrylate (HEA), followed by polymerization of long-chain alkyl acrylate monomers by a seed emulsion method. After being treated with the water repellent agent via a dip-pad-curing process, cotton fabrics could gain desired water repellent (contact angel at 145° and hydrostatic pressure up to 264 mm). Atomic force microscope (AFM) and scanning electron microscope (SEM) analysis showed that the low surface energy WPUA polymers coated the fabric and formed a concavo-convex structure. Benefiting from the robust formation of coatings, the cotton fabrics could obtain good durability for daily laundry. After 50 home laundering cycles, the static water contact angle of the fabric coated with the WPUA could be maintained at 127°. Moreover, the addition of the WPUA to cotton fabrics also exhibited minimally impacting breaking strength and whiteness of the cotton fabric. All the results showed that the new WPUA dispersion is a promising water repellent for textile due to its environment-friendly and cost-effective nature and could be used as a substitute for fluorocarbons water repellent agent.