I have a pair of modal pants. I washed them in the machine in cold water. When I hung them to dry, they were very wrinkled. I ironed them and they were still wrinkled a bit.
Now I throw them into the dryer after washing on very low heat. Once the fabric is almost dry, I remove them and smooth out the wrinkles by hand and hang them to finish drying. They are wearable without ironing, but I do sometimes iron them for a crisp polished look.