Ric Rac
I just bought several hundred yards of R/R. I use it for flower stems. pillow seams, dec trim etc. These days, r/r is usually polyester or in my case nylon. If you keep the dryer heat and iron temp low it shouldn't curl, shrink or melt. Watch the vintage r/r (ebay etc). That may be cotton. Check the content-if it's synthetic it should be fine.