What is the ACTUAL material that you used? Is it Poly Viscose? Poly Cotton? Acrylic? Straight Poly? Cotton Twill?

Are you using 'Poly Viscose' as a generic term for 'non wool' kilts or do you truly know the fiber content of your material?

Where did you buy the material from? That may also help us figure out the fiber content.

I'm not trying to sound harsh or anything... just trying to make sure we know the material so we can tell you how to best care for it as different materials act different ways...

100% Cotton for instance WILL wrinkle and WILL be tough to keep a pleat. This is why most companies that make cotton kilts sew in the edges of each pleat (UK, FK, AK, etc...)

If it is truly PV (I can only speak to the PV sold by MM), it should hold a pleat very well if you iron it on a medium 'steam setting'.