Understanding the Different Types of Carpet Fibers and Yarns

Posted May 4, 2015 by | Leave a Comment »

carpetfibersThere are many different types of fibers and yarns that are used to make carpet. Understanding the difference between the materials can help you decide which type is best for your home.

Carpet fibers are broken down into two main categories, Natural Fibers (Animals and Plants) and Man Made Fibers (Synthetic).

Natural Fibers:

  • Animal (protein)
  • Silk
  • Wool
  • Plant (cellulose)

Seed Fibers: Cotton or wood pulp (Rayon)

  • Leaf: Sisal, Sea Grass, Jute

Man-Made Fibers:

  • Polypropylene / Olefin
  • Polyester / PET
  • Triexta / PTT
  • Nylon
  • Acrylic

Natural Fibers (Animal)

SILK

Silk is the most expensive fiber and is usually only found in very high end, hand-made rugs. Silk is sometimes used as an accent color with fine wool rugs because of the beautiful color, naturally high sheen and soft feel of the fiber. In order to keep costs down, manufactures will sometimes use “faux silk” which mimics the appearance of silk at a much lower cost. Unfortunately, faux silk does not have the same performance of true silk.

Silk fibers come from the cocoons of silk worms. The cocoons are unwound (called reeling), producing extremely long fibers. Silk is the only natural fiber that can be considered a continuous filament fiber as opposed to a staple fiber. Silk has a higher tensile (pulling) strength than a similar filament of steel. Silk is lightweight and stretchable (stretches up to 20% of its length), but is not elastic. Silk will only contract about 2% of its length once it has been stretched. Silk has good insulating capabilities and is flame resistant. Similar to wool, silk is sensitive to alkalinity and chlorine bleach.

WOOL

Wool comes from the fleece of the sheep. Wool is produced in countries like New Zealand, Argentina and the United Kingdom. Wool is considered a green product because it is renewable and does not harm the sheep during or after the shearing process. The opaque fiber (as opposed to synthetic fibers which are translucent), does not refract or reflect light which gives it a naturally rich appearance that helps to hide soil in between cleanings. Because the fibers come from the short hair of the sheep, it is considered a staple fiber. Wool is non allergenic – does not promote the growth of bacteria and dust mites or give off harmful emissions. Wool is naturally stain resistant, absorbs and neutralizes polluting gasses such as formaldehyde, Sulphur dioxide and nitrous oxides. Wool fibers are naturally resilient; the sheep’s hair grows in a spiral. Wool is resistant to fire (chars but won’t burn) and has excellent insulating properties. Wool also resists dust mites which are harmful for allergies.

Wool absorbs and releases moisture. It can hold up to 10 times its weight in moisture which means it will absorb moisture in the summer and release moisture in the winter.

Wool is more expensive to produce than other synthetic fibers, but will last longer. It is easy to die and comes in rich colors.

On the down side, wool absorbs protein based stains and is sensitive to dye stains like tea, coffee, and wine.

Natural Fibers (Plant)

RAYON

Rayon fibers are made from regenerated cellulose derived from cotton fiber or wood pulp. Rayon is also known as “faux silk” or “refurbished cotton”. Rayon fibers have a high sheen and soft feel. Rayon is much less expensive to produce than silk. Unfortunately, rayon fibers do not perform well with even moderate use. Rayon fibers stain easily and are not resilient. The do not hold their twist and will show traffic patterns easily. Rayon fibers will also tend to run or “bleed” during the cleaning process. Rayon is sometimes used as an accent color in carpet which minimizes the performance issues.

SISAL

Sisal rugs offer a natural textured look, a favorite of designers. The sisal fiber is derived from the Agave Sisalana cactus plant. Sisal grows in semi-arid regions. The largest producers are located in Northeast Brazil and East Africa. Sisal fibers can be up to 3’ long. They are harvested by hand from the leaves of the cactus plant.

Sisal is stronger and more durable than other natural fibers and is therefore preferred for carpet and rugs. Sisal absorbs moisture readily and is recommended for low / no moisture areas.

While beautiful, Sisal can be difficult to clean. Once a stain is set, it can be difficult to remove. Sisal should therefore be treated with some form of stain protectant to help prolong the life of the rug.

SEAGRASS

Seagrass originates from fast growing perennial grasses that reach 4 to 6 feet in height. The grasses are grown in wet places with their root system sitting in water a portion of the year. Materials are often hand woven on power looms. The seagrass fibers have a natural variation in color. Seagrass is often used in its natural color (not dyed), because it repels moisture. Different from Sisal, seagrass is spill resistant. Seagrass is susceptible to mold and mildew and should not be used in bathrooms, kitchens, basements or other humid environments.

JUTE

Jute comes from the stalk of the jute plant. Jute is a long, shiny fiber that can be spun into course, strong threads. The fibers are off white to brown and are 3 to 15 feet long. Jute fibers are mostly composed of the plant materials cellulose, lignin and pectin. Jute is a rainy season crop that grows best in warm, humid climates like China, India and Bangladesh.

Jute is highly absorbent and will shrink when it gets wet. Jute is mainly used as a backing material. Caution should be used when cleaning a carpet with a Jute backing as the carpet will shrink.

Man-Made Fibers

POLYPROPYLENE / OLEFIN

Polypropylene was first introduced in the carpet industry from Italy in the Mid 1950’s. Polypropylene, also known as Olefin, makes up roughly 30% of carpet sold in the United States. Polypropylene is moisture resistant (it will only absorb 1/10 of 1% its weight in water) and will not fade in sunlight (good for indoor / outdoor carpet).

Polypropylene is solution dyed and therefore can be cleaned using strong cleaners – bleach will not harm the fiber (note the manufactures warranty before using bleach to clean the rug).

Because polypropylene is solution died, it can only be produced in a limited color range.

Polypropylene is usually sold in a loop or a dense low cut pile because of its poor resiliency. It has poor abrasion resistance and a low melt point (you can leave a permanent mark in the carpet by dragging furniture across it.

POLYESTER / PET

Polyethylene Terephthalate, known as Polyester is made from recycled plastic bottles.

Polyester is solution dyed and is produced as a staple fiber. Similar to polypropylene, polyester is stain resistant, fade resistant and is not affected by bleach (see use and care instruction). Polypropylene is produced using a fine denier (thickness of the fiber) and has a soft, luxurious feel. Polypropylene is less expensive than nylon.

Polyester, however, has a low resiliency and is susceptible to wear, matting and traffic patterns. Polyester is recommended for low traffic areas only.

TRIEXTA / SMART STRAND / PTT

Poly Trimethylene Terephthalate (PTT) is made by Dupont under the Triexta name. Mohawk markets the fiber under their brand “Smart Strand”. Triexta is a subclass of Polyester, but has characteristics that are significantly different enough from Polyester to have its own, unique classification. The main differentiator from Polyester is its durability. The Triexta fiber has been shown in research to have more resiliency and resist traffic patterns better than Polyester. Because the product has only been on the market for a few years, time will tell if the product holds up in real life situations.

Under the Smart Strand brand, Mohawk sells Smart Strand “Sorona” which is produced using 37% corn glucose. Benefits of using corn glucose include:

  • Fewer chemicals means lower VOC (off gassing)
  • Uses 30% Less energy in the production of the fiber compared to nylon
  • Emits 63% less greenhouse gasses in production of the material
  • Producing 7 square yards of Sorona reduces the equivalent of 1 gallon of gasoline

NYLON

Dupont first introduced Nylon in 1938. Nylon is a petrochemical synthetic fiber made from carbon, nitrogen, oxygen and hydrogen. Treated Nylon fibers are sometimes referred to as 6th generation.

65% Of all carpet sold in the United states is made from Nylon fiber. Nylon is the most durable of all synthetic fibers. Nylon Resists wear and abrasion and has good resilience. Nylon has good yarn memory (holds a twist). Almost all Nylons are treated with some type of stain resistance which aids in cleanability.

Nylon carpets are available in a wide range of colors and can be produced in BCF or staple yarns.

ACRYLIC

Because acrylic has a low sheen level, it is now sometimes as “art wool”. It is often used as a blend with wool (usually 20%) to help reduce the price while maintaining the overall appearance of wool.

Acrylic resists soiling, stains, static and mildew. It’s easier to clean than wool and unlike wool, acrylic is not susceptible to moth damage. Acrylic colors are bright and resist fading in sunlight

While wool holds moisture, acrylic wicks it away.

But acrylic fiber carpets have some drawbacks that have limited their use. Acrylic is not as durable as wool, nor as resilient. It has a tendency to become fuzzy as fibers deteriorate and to pill like polyester. Acrylic is easily stained by oil and grease.

Pure acrylic fiber is more popular for scatter rugs. Because it wicks water and dries quickly, it’s often seen in bathroom rugs.

YARNS

BCF YARN

(Bulked Continuous Filament) The Long filaments of fiber are formed by melting polymer chips. The liquid is then forced through a plate with thin holes (called a spinneret). As it cools, it solidifies into a long continuous filament (single strand).

STAPLE YARN

Staple yarns are produced in short lengths and spun and twisted together to form long threads of yarn. Yarns can be spun into any size yarn bundle. Very small yarn plies are used for pinpoint Saxony’s. Very large bundles are used for shag or cabled yarns. Staple yarns are also used for beautiful velvet plushes.

Staple yarns will shed loose filaments after carpet installation as some of the yarns that did not get fully glued to the backing will work their way to the surface of the carpet. This process of “shedding” loose fibers will be most noticeable after the installation and should not last more than a few months.

Learn more about the carpet products offered at Kashian Bros »

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