The Gore-Tex system, invented in 1978, uses a proprietary material that is fastened to the inside of the pants through a lamination method.
This lamination gives the consumer more variety because the membrane can attach to different types of material instead of being designed with only one fabric in mind.
They discovered a way to attach the membrane, through an industrial lamination process, to the inside of various types of fabrics.
Products with food or oil stains, waxy coatings, stickers, foil accents, or lamination are generally unable to be recycled.
In some cases the inner layer is formed not by invagination but by proliferation or by de lamination.