We have tried: we ironed the iron-on patch according to the instructions. We set the iron to 150°C. Then we washed the garment 5 times at 40°C. The patch holds after this test, it did not come off.
User manual:
1) On a clean dry cloth/fabric lay the application, the fabric can not be starched.
2) Place it on the ironing board so that the iron-on patch is underneath the fabric.
3) Set the iron to 150 ° C.
4) Iron under more pressure for 8-10 seconds, then allow to cool.
We recommend to sew the patches to clothing to avoid peeling off after washing.