Wrinkle-free pants: How is a permanent crease made?

[rseneres]

I have some great wrinkle free cotton slacks but every time I wash them the crease from my previous pressing disappears, and I must re-press them to create a new crease. However I have bought wrinkle-free cotton slacks before which had wrinkle-free characteristics as well as a permanent factory-made crease that made the slacks virtually maintenance free. How can one make a permanent crease in such material if one was not made at the factory?

[astro]

You can’t, they use a formaldehyde compound and an industrial press to make the crease during manufacturing.

Sources of formaldehyde in the home include building materials, smoking, household products, and the use of un-vented, fuel-burning appliances, like gas stoves or kerosene space heaters. Formaldehyde, by itself or in combination with other chemicals, serves a number of purposes in manufactured products. For example, it is used to add permanent-press qualities to clothing and draperies, as a component of glues and adhesives, and as a preservative in some paints and coating products.

[3waygeek]

That may be the way they do it now, astro, but I used to have some pants whose crease was held by a very thin bead of silicone sealant applied along the inside of the leg.

FWIW, I have several pair of new Dockers that were supposed to have the permanent crease – it was permanent through one washing