I have many kinds of Velcro but only use the sticky back for items not being sewn. And this is for everyone be careful of the Industrial sticky back Velcro Only use it on something you don't plan on changing out in a very long time. It's like super glue.

Velcro comes in many different ways. The sticky back stuff is not meant to be sewn. I buy the kind labeled "sew-on" in strips, cut the size I need, and attach it with a zig-zag stitch all around.

there is also an iron-on velcro that has good reviews. comments included that it washed very well and seemed to adhere better (not worse) after each washing. I have some but have not used it yet.

The sticky-backed Velcro was terrific for attaching a valance to the board, but I would not use it in sewing -- it is almost guaranteed to give the problem you are experiencing. When I buy Velcro, I spend a LOT of time reading the packaging to make sure I am getting the width/color/strength/etc that I want. Sticky is not really for sewn applications.