Synthetic Fibers in Carpets

Nylon
The fiber nylon was ushered in first by the DuPont Chemical Company in 1938. A few years later, after a great deal of development, nylon became the first synthetic fiber to be used in the entire carpeting industry.

The first 3 generations of fiber went through many problems with the worst being staining. The fourth generation fiber of nylon had a mill applied finish that solved a majority of the staining problems. The ability of the fiber to repel water and oil based
spills in addition to as soil assisted to move nylon into the top selling list of carpet fibers at that point.

After various other changes, the DuPont company ushered in the fifth generation nylon fiber. This stain resistant fiber would repel most stains if addressed in a sensible amount of time. This fiber is more accurately called an acid dye blocker in that it doesn't allow acid dyes to penetrate and stain the fiber.
The protective coating is applied and fills the dye sites with anionic molecules.

Tip
An simple way to test fiber for the presence of a fluorochemical is to cut a few fibers from a non traffic area and apply a few drops of oil and water mixture. If it beads up, then there is an active fluorochemical present.

If testing for the presence of the acid dye blocker, you should once again cut a couple of fibers from a non traffic area, then immerse the fibers in a red kool-aid mixture and wait for five minutes or so. Take the fiber from the liquid and flush with neutral detergent solution. If the acid blockers are present and active, there will be no discoloration.

Polyester
The fiber of polyester was first introduced into the fashion industry around in the 1950s. By the late 1960s, polyester was brought in into the carpet industry as a face yarn. In hand, feel, and appearance it is similar to nylon, although it doesn't possess equal resiliency.

Polyester doesn't absorb water based spills, isn't affected by urine or kool-aid, but it will absorb oil based spills. Polyester is non allergenic and mildew resistant.

Acrylic/modacrylic
Both of these fibers were first used as carpet yarns around the late 1940s. They disappeared around 1988 due to the competition from other fibers.
In was reintroduced to the market around 1990 in Berber styling. This was done so that people could take advantage of the wool like appearance, hand feel, and the
fact that its more spot repellent, much easier to clean, and not damaged in the ways that wool is.

Olefin
Olefin is the latest of the synthetic fibers to be adapted to carpets. Once only available in continous filament, it is now produced in staple form as well. Olefin has a wide variety of uses that include primary and secondary backing of tufted carpets, warp yarns, and other uses as well.