Is nearby a track to prevent a iron on print from blistering?

My friends and I created a computer design and ironed it on to a white cotton t-shirt. To iron it on, used this industrial like iron and ironed respectively side for about 30-45 second. Is there a bearing to prevent the design from peeling after the 1st purify?
Answers:    Wash on gentle cycle near cold water and mild detergent and strip dry. Never put it in the dryer. And don't iron over it again.
try wash it inside out that usually helps me