Patches, like everything else in the challenges, come in Bronze, Silver and Gold. Once unlocked the perks are permanently unlocked. All patches are displayed on the right hand side of the screen once you have selected a challenge. Their outline will be either bronze, silver or gold, which displays what level you have unlocked.
To unlock each rank you will need to do the following:
Bronze rank in the main challenges unlocks the associated Bronze patch.
Silver rank in the challenge unlocks the associated Silver patch
Gold rank in the challenge unlocks the associated Gold patch
Note: You only need Bronze in each main challenge for the trophy.
Once you earn the patches, they can be used in the main game too.