Don't Iron Your Patches (Updated) November 11 2014, 0 Comments
When considering ways to attach your patches to any surface, avoid direct ironing. I have received a report that some threads (especially the glowing thread on the SAR patch) tend to melt under heat. I am awaiting clarification on the purpose of the patch backing from the manufacturer, but until then I would advise sewing your patches on or using an independent iron-on stick.
I have worked with products before that are paper on one side and solid glue on the other. You use it by cutting out the shape of the item you are attaching, iron on the paper side, peel it off, then stick the item onto the hot glue and apply pressure while it cools, usually with a stack of books. This helps hold it in place for sewing afterwards.
I'll update when I hear back from the manufacturer, but for now my advice is to either sew or wait. The only recorded instance of melting threads is on the SAR patch, which is the only one with glow-in-the-dark thread.
Update: Just got clarification, the backing is military grade PVC backing designed to protect the patch from shrinking or losing its shape in the laundry. It is not made for iron-on adherent. The patches will melt before it does if you try to iron them on.