SOUFA was brushed on 100% cotton (cotton) and after drying, it was ignited with an alcohol lamp.
SOUFA gives cellulose a high level of flame resistance, so it is easy to stop burning. However, it does burn.
As for the flame retardant mechanism, SOUFA settles on the cellulose of cotton and reacts to heat when heat is applied, forming a thin glass film on the cotton surface. At the same time, SOUFA combines with the carbon of cotton to form an oxygen-blocking film.
Therefore, once the cotton gets burnt, it will not spread further. If it is just a brush coating, the texture will not be affected much.
However, if too much is applied, it is thought to become hard. This is because the boric acid has a property of slightly hardening cellulose.