Flame retardant back-coated PET fabric with DOPO-based environmentally friendly formulations

There is a great demand for nontoxic flame retardants (FRs) in textile industry to replace harmful halogenated counterparts. On the other hand, the availability of eco-friendly phosphorus-based FRs for application on synthetic textiles are scarce for, especially for the back coating application. Thus, in this work, non-toxic phosphorus FRs such as EDA-DOPO (ED) and DOPO-PEPA (DP) were applied to PET fabric via a back coating process. For immobilizing these FRs on fabric, three different polymer resins, namely polyurethane, vinylacetate and acrylcopolymer, were utilized. The FR performance of fabrics was evaluated via a vertical burning test (FAR 25.853), a standard used commonly in aviation industry. For ED formulations (all resins), 5 % phosphorus (P) content on coating was sufficient for the textiles to pass the fire test. However, fabrics coated with DP formulations failed the fire test for the same P content. To further improve the FR performance of DP formulations, melamine was incorporated as a synergistic additive. In order to understand their FR behavior, thermogravimetric analysis (TGA) and direct insertion probe-mass spectrometry (DIP-MS) analysis was performed to elucidate the FR action of the additives. Herein, it was shown that DOPO-based FR compounds were first time successfully applied for the back coating application in textiles and their gas phase action was essential to pass the vertical burning test.