Cotton is a natural fiber composed mainly of cellulose, which is a polymer. The cellulose chains in cotton, composed of microfibrils, have only hydrogen bonds between them, so there are no covalent crosslinks to force the cellulose chains to return to their original position when deformed by wrinkling or laundering. In the late 1950s, SRRC scientists initiated work on wrinkle resistance so that fewer wrinkles would form and those that did would fall out on hanging. In other words, the cotton would recover, much like wool does. The next stage was wash and wear: making a wrinkle free garment that would come out smooth after washing. But wash and wear had a problem; it would not hold a crease. That led to the next stage, sometimes called permanent press, but more accurately termed durable press, in which wrinkle resistance and durable creases could be achieved in cotton garments.

In the beginning, scientists used urea-formaldehyde resins, which are relatively inexpensive, to produce cotton garments that had wrinkle resistance and shape retention. Later, melamine-formaldehyde condensates exhibiting improved properties were introduced. SRRC scientists understood in the early years of research that wrinkle resistance could be imparted to cotton by polymer forming reagents and surface treatments, but that better and more durable levels of wrinkle resistance could be achieved when the reagents actually penetrated the fibers and reacted with the cellulose. The result was a chemical modification of the fabric by crosslinking. This means that the cellulose molecules, which are long chains, are chemically linked by short molecules to make them more rigid and the fabric wrinkle resistant. The crosslinks between cellulose molecules are analogous to the rungs on a ladder. Fabrics treated with these formaldehyde resins when smooth will return to smoothness when washed.

Over the years, SRRC scientists experimented with new finishing agents with the goal of trying to reduce the amount of the formaldehyde used in durable press processes because of safety concerns. Formaldehyde derivatives were commonly used because they are cheap and highly effective as a wrinkle proofing agent. Formaldehyde derivatives are fine reagents, except that they are not stable. This means there is a very slow release of formaldehyde during processing in the mill and during storage of the treated fabric or finished garment. Formaldehyde release raised safety concerns, so over the years SRRC scientists worked to control the amount of formaldehyde released in durable press processes.

Researchers succeeded in reducing the amount of formaldehyde released from three thousand parts per million to about 250 parts per million, which, according to Bethlehem Andrews, "is almost negligible, and at that point, you can hardly reduce it more." Better preparation of the finishing agents helped lower formaldehyde release, but finding newer and more stable finishing agents proved the best method. The major success in this area came with the introduction of DMDHEU (dimethyloldihydroxyethyleneurea), or more correctly 1,3-bishydroxymethyl-4,5-dihydroxy-2-imidazolidinone. DMDHEU was first patented by BASF, but SRRC scientists researched capping agents added in the crosslinking process that further lowered the formaldehyde release.

Of course, eliminating formaldehyde altogether became a goal. While some successes were achieved in finding formaldehyde-free reagents, there were problems. The formaldehyde-free reagents are more expensive and many of them cause discoloration. Some have toxicity problems of their own. One safe but relatively expensive reagent, DHDMI [dihydroxydimethylimidazolidinone (1,3-dimethyl-4,5-dihydroxy-2-imidazolidinone)] produced moderate levels of resilience and is used in infants' clothing. Polycarboxylic acids are the most successful of the non-formaldehyde agents, particularly BTCA (butanetetracarboxylic acid). SRRC scientists discovered a series of catalysts to enable these acids to react with cotton fabrics to achieve the crosslinking needed to impart durable press properties. The greater cost of formaldehyde-free agents, however, has limited their commercial adoption.

In addition to safety concerns, there were other problems with the finished cotton treated with nitrogenous formaldehyde-based substances. The main problem was chlorine absorption. The garments treated with melamine-based finishes would turn yellow. The urea-type finishes would retain chlorine and, in the words of Robert Reinhardt, an SRRC scientist, "if they were subjected to heat, a touch-up ironing, the chlorine would be released and generate acid and seriously diminish the strength of the fabric."

Another problem with formaldehyde treatments was strength loss, which is called "crosslink embrittlement." The goal in all treatments was to achieve a smooth appearing fabric that was not so weak it would fall apart. In some of the formaldehyde treatments, as Noelie Bertoniere says, "if you bent forward your shirt would have s plit up the back, and that's not acceptable." Or, as Reinhardt says, "if you have too many crosslinks in there, it's like a lead pencil, it won't bend, it'll break." This is still a major aim of the textile industry: to come up with a wrinkle free treatment that does not cause the fabric to lose strength. As another researcher, John Frick, put it: "The end of all, which we could never quite reach, was to do the finishing without damaging the strength and the wear resistance of the cotton." A related aim is to improve the wear life of a garment, so that, for example, cuffs do not fray.

Many approaches were taken to solve these problems. One avenue was to blend cotton with polyester with produced a stronger fabric but not a stronger crosslinked cotton component. SRRC researchers also explored additives which did not chemically attach to the fibers. One such additive was emulsified polyethylene, patented by Reinhardt, which stays on the surface and essentially protects the surface from wear. Polyethylene softens cotton fabric, gives it more strength, and increases abrasion resistance substantially. It is also inexpensive a nd remains much in use.

Durable press has helped to revive the cotton textile industry. Much of the work in improving durable press, in discovering crosslinking mechanisms and additives to improve those mechanisms, was done at the Southern Regional Research Center. But imparting wrinkle resistance without losing strength while at the same minimizing abrasion remains the primary research objective for the cotton fabric industry.