Synthetic Carpet Fibers

The majority of carpets are made from synthetic fibers. There are many reasons why synthetic fibers are generally preferred over natural fibers. They are more durable, have better stain resistance and are often cheaper. In addition, the properties of synthetic fibers and fabrics can be easily taylored to the application by varying the chemical composition and the process conditions. Compared to natural fibers, synthetic fibers are usually more water, stain, mildew, heat and chemical resistant.

There are four major classes of synthetic fibers used in carpets: olefin, nylon, polyester, and acrylic. Each type of fiber has pros and cons in regard to durability, cost, and stain resistance.

The fibers used in the manufacture of carpets can be divided into two main classes: staple and continuous filaments. Olefin is typically produced in continuous filaments, whereas polyester is mainly produced as a staple fiber. Nylon is produced in both continuous and staple, and natural fibers like cotton and wool are always staple filaments. In general, continuous filaments and staple fibers of long staple length result in more durable carpets because short staple filaments in lower quality carpets will loosen and accumulate on the carpet surface over time, whereas high-quality staple yarns are much more durable. They are often preferred over continuous filaments because they allow for more styling flexibility.

Not only the type and quality of the fiber but also the manufacturing method (woven versus tufted1, cut pile versus loop pile2), the construction (fiber density, backing, weave pattern etc.), and the additives (dyes, adhesive) will determine the quality of the carpet.

1. Nylon

Nylons are the most popular carpet fibers. They are an excellent choice for all traffic areas. They are exceptionally strong, elastic (stronger than polyester) and have excellent abrasion resistance, tenacity, and elasticity. They are also easy to wash and to dye in a wide range of colors. The filament yarns provide a smooth, soft, and lightweight structure of high resilience. However, nylon carpets are usually more expensive than polyester carpets.
The two most popular Nylon fibers are polycaprolactam (Nylon 6) and polyhexamethylene adipamide (Nylon 6,6). The later has superior performance but is  more expensive and more difficult to process.

2. Polyester

polyester (polyethylene terephthalate, PET)3 is a very popular and versatile fiber. It is the most important synthetic fiber in the garment industry and has been used in carpets for many years. Polyester yarns and carpets made from this type of polyester are strong, elastic, and have high abrasion and wrinkle resistance. However, polyester fibers are not as strong and elastic as nylon fibers but have better stain resistance.

The newest polyester carpet fiber is Triexta. This fiber combines some of the best properties of nylon with those of conventional polyester (PET). For example, triexta has the excellent elastic recovery and resilience of nylon and its tensile strength is only slightly lower than that of PET fibers. Triexta fibers are usually much softer than PET fibers and have a wool-like feel. They also hold dies better.

3. Olefin

Olefin fibers have a similar appearance to wool. This is one reason why this fiber finds applications in area rug. It is often a good choice for loop carpets like Berbers. The fiber is strong, elastic, has good abrasion resistance and has excellent resistance to staining, chemicals, mildew and fading. It is an excellent choice for both indoors and outdoors like artifical sport turfs. Olefins are usually the least expensive carpet fibers but they also have lower resilience than nylon and polyester, meaning olefin fibers do not “bounce back” as quickly after being compressed by foot traffic.

4. Acrylic

Acrylic fibers are made from polyacrylonitrile. The fiber is lightweight, soft, and warm, with a wool-like feel and can mimic natural fibers such as cotton and wool or can be blended with them.  The fiber has fair to good abrasion resistance and good resistance to staining, chemicals, mildew, and fading. However, acrylic fibers are not as durable as the other three major types of carpet fibers. Acrylics are usually not a good choice for high traffic areas.

1Most of today's carpets are tufted rather than woven. This process resembles a sewing process. The yarn is sewed into the backing with hundreds of needles.

2Loop Pile is a carpet surface consisting of uncut loops which maybe woven or tufted whereas cut piles consist of cut loops, hence the name "cut pile" carpet. Cut pile is usually less susceptible to traffic wear and is the most widely used type of residential carpet.

3This is a very common plastic frequently used for plastic bottles (PET or PETE) and easy to recycle.