Won’t wrinkle
Resists wrinkles
Wrinkle resistant
Heroically wrinkle resistant
Wrinkle defiant
A wonder of wrinkle-defying elegance
Wrinkle-free
Virtually wrinkle-free
Wrinkleproof
Virtually wrinkleproof
Guaranteed not to wrinkle
No wrinkles — guaranteed
Never needs ironing
Wrinkle shedding
Magically sheds wrinkles
Scorns wrinkles, shuns dry cleaning
Defies wrinkles and pickpockets
Passes the wrinkle test with flying colors
Sends wrinkles packing
Packs without wrinkling
Unpacks without a wrinkle
Go for days without a rumple
Say arrivederci to wrinkles
Say farewell to wrinkles, au revoir to ironing
(taken from McSweeney’s)