The first permanent press process was invented by Ruth Rogan Benerito, research leader of the Physical Chemistry Research Group of the Cotton Chemical Reactions Laboratory and This process was based on formaldehyde , however in 1987 the chemical DMDHEU (1,2-Dimethylol-4,5-dihydroxyethyleneurea) demonstrated superior characteristics. In 1992 Haggar first began to employ DMDHEU in wrinkle free garments However, DMDHEU still releases some formaldehyde so it is not entirely without health risk.
More recently, nano technologies have been applied to the problem of wrinkles in clothing. In 1998 the Nano-Tex company was formed by chemist David Soane to apply a "nano technology" process to fabrics Rather than coating the fabric with a resin based on formaldehyde, the chemical utilizes "nanotechnology – tiny molecules that permanently attach to fibers without clogging the fabric weave" The technology is used in clothes sold by major brands such as Dockers, Eddie Bauer, Gap, Old Navy, and Perry Ellis However, some believe that this technology is not without risk and (as of November 2007) the safety of nanotechnology in general has hardly been tested and is largely unproven.
Most older clothes dryers feature an automatic permanent press setting, which puts clothes through a cool-down cycle at the end of the normal heated drying cycle. Modern dryers tend to include this as a standard feature
In older washing machines, the permanent press setting sprays moisture during the spin cycle to maintain the moisture content of the permanent press fabrics above a certain specified limit to reduce wrinkling
It is generally advisable with older machines to wash clothes on the regular cycle, while drying on the permanent press setting Consult the garment's laundry symbols for more detailed instructions.