It is a fact that 100% Cotton fabrics will wrinkle. Perhaps you are too young to remember the days when you never went outside in a cotton shirt that had not been starched and ironed.

In fact Cotton looks better and better the more you iron it. Shirt manufacturers have known this for years. Some dress shirt manufacturers iron the fabric after each and ever step in the making of the shirt. Perhaps 25-30 times for one shirt.

To think that you will be able to buy a Kilt made from 100% Cotton fabric and not have to iron it is not realistic.

I caution every customer that a Kilt made from my 100% Cotton Collection will need ironing. I even show them how to iron their Kilt.

Other fabrics used in Kilts will wrinkle more or less depending on the fiber content. Acrylics actually wrinkle faster. It takes less pressure to cause wrinkling. But because the nap of acrylics is usually fuzzier and the weave looser the wrinkles are less noticeable and will drop out from their own weight sooner.

Wool in the weights usually used in Kilts (13oz per fabric yard or more.) will wrinkle. But Wool is a very special fabric. The heavy weight, and the Worsting of the fibers as it is spun and woven, will allow short term wrinkles from sitting to fall out in just a few moments.
This is one of the reasons heavy weight Worsted Wool is such a perfect fabric for Kilts.

P/V, True P/V, meaning a blend of Polyester and Rayon as woven by Marton Mills is the fabric least prone to wrinkling that I know of. I have Kilts in my shop that have been washed many times in the washer and dryer. Even after two or three hours of sitting on them there are no wrinkles. Many of these Kilts have never had an iron touch them since I made them.

So, in general, the lighter the weight of the fabric, and the higher the Cotton content, the more it will wrinkle and the more you will need to iron it.