custompat112
Each patch has a "heat seal" backing made from a thin layer of clothing glue. This glue does not stick at regular temperatures. You activate the stickiness by heating up the backing using an iron. When the glue melts, it sticks to the surface. Once the glue cools, it dries and hardens, effectively cementing it to that surface. The stickiness of the glue will not last forever, but every time you iron the surface, the glue re-sticks itself. Cotton, denim, blend, and wool work well with iron on patches, but the patches won't adhere to materials like nylon, satin, leather, 100% polyester, and other similar fabrics. Similarly, vinyl is too sensitive to use with iron on patches.