Carpet Fibers and Yarn: Types, Characteristics and Applications

Carpet Fibers and Yarn: Types, Characteristics and Applications

Saiful Sabuz
Department of Textile Engineering
Ahsanullah University of Science & Technology (AUST)
Email: saifulsabuz.tex23@gmail.com

 

Introduction:
Carpet is a textile floor covering material which is comfortable to walk on, can be cleaned, and offers a luxurious appearance. It is typically consisting of an upper layer of pile attached to a backing. Carpet is also used for table and wall coverings. It is made from natural and synthetic fibers, and comes in a variety of styles, patterns, and colors. Carpets in a house help to reduce noise levels and minimize heat loss through the floor. They are also more comfortable to lie on or to sit on than a hard wooden floor. Carpets are often classified by the type of fiber used to make surface yarns. On the carpet sample, you will find the generic fiber name used for surface yarns.

Carpet Fibers and Yarn:
The fibers available for carpet manufacturers to blend fall into two distinct categories – natural and man made fibers. Yarns used in carpets require different fiber properties than yarns used in apparel and home textiles.

The most important yarn properties for carpet manufacturing are:

Fineness:
The titers of most carpet yarns are between 4.4 and 28 dtex. The titer range of the filament yarns for carpet production is 650 to 5,000 dtex. The titer of the single fiber is similar to that of coarse wool fibers.

Structure:
Most carpet fibers are characterized by highly elastic structural crimp.

Stability to stress:
Good stability is of major importance especially for the pile of needle-punched, cut-pile, and boucle carpets.

Voluminosity and softness:
To achieve these characteristics in carpets, voluminous yarns that produce a dense and voluminous surface area without using too much material are preferred. For the production of carpet, mostly chemical fibers are used, but natural fibers can also be used. Below figure gives a list of the most popular carpet fibers.

Fibers used for carpet production
Fig: Fibers used for carpet production

For tufted carpets, filament yarns are used. If the carpets are tufted with cut pile in single colors, the PA fibers have to be spun into staple fiber yarns according to the mock-worsted spinning method. The entire lot has to be mixed and homogenized very thoroughly to avoid streaks in the carpet color.

In addition to the yarns, the backing material is important for the carpet production, which can be nonwovens, woven fabrics, and woven fabrics with a nonwovens layer.

Natural Fibers:

Wool: The most popular of natural fibers and a great renewable resource, wool is exceptionally suited to being used as a carpet fiber because it combines excellent resistance to foot fall with an uncanny knack of looking good for years. Wool Carpets are also resistant to combustion and under normal conditions provide a great anti-static flooring option.

Silk: Being so delicate, silk is rarely used in carpet but it does bring a certain something to the finest handmade rugs, particularly those from the Middle East and Indian regions.

Jute: Used mainly in the backing of carpets from a traditional point of view, jute is gaining popularity as a natural fiber floor covering and its depth of texture makes it great for rugs.

Coir: Coir is made from the fibers of coconut husks and it is a strong and resilient fiber. The husks are harvested and then soaked for months before being beaten into submission, washed and then dried. The pale yellow fibers are then spun into yarn that is then woven into flat weave carpeting or as many people will recognize it, into cut pile doormats that are great at removing dirt and moisture from soles.

Flax: Only used occasionally in loop pile and flat weave rugs and carpets.

Sisal: These are some of the toughest fibers in the business and unlike most natural fibers it can be dyed. When combined with wool, sisal can also take on a softer side and is being favored by natural flooring manufacturers for its aptitude at creating colorful, natural floors.

Seagrass: Hailing from the paddy fields of China, Seagrass is a rapidly replenishing resource. Once the fields have been flooded with seawater, the fiber is harvested and spun into yarn that has an impermeable quality. While this makes it hard to dye, it also makes it relatively easy to care for.

Man Made Fibers:

  1. Acrylic
  2. Polyamide ( Nylon)
  3. Polyester
  4. Polypropylene
  5. Viscose

Carpet Yarn:
All carpets are made from either natural fibers, man made fibers or a combination of both that are spun into yarn that is then woven or tufted into the finished article to be found in carpet retailers throughout the globe. Spinning the yarn itself is a skilled job and one that has created specialist companies serving carpet manufacturers.

Stages in yarn spinning:
Raw fibers are blended together in precise proportions according to the ‘character’ and ‘handle’ of the yarn required for the carpet in question

The blend is scoured, pulled and teased – in carpet speak called carding – until it is straighter, whiter and free of natural burs and foreign bodies

The fiber is systematically opened up , layered and cross layered before the resulting ‘web’ or ‘spat’ is split into ‘slubbings’ that are then pulled and twisted on a spinning frame. This helps to add strength to the single strand of yarn

Two or more of these strands are then twisted together – ‘doubled’ – and this results in a yarn with high tensile strength capable of being tufted or woven by the latest high-speed machinery at maximum efficiency and at the lowest production cost.

Color is introduced either at the raw fiber stage or when the yarn is spun into the thickness and length suitable for the carpet in question.

Different Types Carpet Fiber Characteristics, Advantages, Disadvantages and Applications

Fibers used in the carpet surface:

Nylon Carpet Fiber:
Nylon carpet fiber is the most popular fiber (about 90% of residential carpets and 65% of all carpets). Nylon carpet fiber is a good choice for all traffic areas because it is durable and static free, maintains fiber height, and resists soiling, staining, and mildew. Nylon fibers, which are dyed after production, maintain color. Some nylon carpet fades with sunlight. It comes in continuous or spun fibers. Spun yarn is made of short lengths of fibers that are spun together. Thus, continuous filaments are less likely to unravel.

Nylon fiber carpet
Fig: Nylon fiber carpet

Nylon carpet fibers can be made to resist stain from certain acidic artificial and natural colourants found in soft drinks, juices, coffee and red wines, by grafting a phenyl–vinyl and ether–maleic anhydride copolymer to the fibre surface using UV light and a photoactivator in the solution. However, there are other techniques for blocking the stain-sensitive amine ends that are more commercially applicable and efficient. They include (1) the post-treatment of nylon carpets with an alkali metal silicate in a phenol–formaldehyde product or with a sulphonated naphthol or sulphonated phenol–formaldehyde product at a specific pH, (2) manufacturing of carpets with only cation-dyeable nylon yarn and dyeing or printing them to shade and acceptable light fastness with premetallized or acid dyes and (3) melt-spinning of fibers – pigmented or producer-coloured fibers – from nylon polymer containing a high level of a sulphonated derivative.

Nylon Fiber Facts:

  • Yarn-forming substance of any long-chain, synthetic polyamide having recurring amide groups as an integral part of the polymer chain.
  • Offered as BCF or staple, both used for commercial application.
  • Sold as a solution-dyed yarn.
  • Accounts for 65% of all face fibers in carpet products.

Advantages:

  1. Good bulk and cover
  2. Good crush resistance
  3. Long wearing
  4. Clear colors
  5. Range of dye depths
  6. Excellent luster range
  7. Good performance, even at low weights
  8. Good soil resistance
  9. Responds we to cleaning

Disadvantages:

  1. Higher cost
  2. Easiest of synthetic fibers to stain with typical food and beverage spills (fabric protection helps fight this problem)
  3. Will lose color in presence of bleach, especially chlorine

Applications:
Practically any style carpet, in any price range, can be made with Nylon and easily dyed and finished by any method.

Acrylic Carpet Fiber:
Acrylic carpet fiber offers the appearance and feel of wool without the cost. Acrylic carpet fiber has a low static level and is moisture and mildew resistant. It is commonly used in Velvet and Level Loop constructions; it is often used for bath and scatter rugs.

Acrylic fiber carpet
Fig: Acrylic fiber carpet

Acrylic carpet fiber is known as art, art wool, or man-made wool because it is an artificial fiber. These fibers provide the look and feel of wool at a fraction of the cost. Acrylic carpet fiber resists static electricity, moisture, mildew, fading, crushing, staining, and sun damage. However, acrylic fiber is not durable enough for high traffic areas (it fails under abrasion when compared to other fibers).

Acrylic fibers are produced from acrylonitrile, a petrochemical. The acrylonitrile is usually combined with small amounts of other chemicals to improve the ability of the resulting fiber to absorb dyes. Some acrylic fibers are dry spun and others are wet spun. Acrylic fibers are used in staple or tow form. For a detailed production flowchart (wet and dry spun), go here.

These fibers are modified to give special properties best suited for particular end-uses. They are unique among synthetic fibers because they have an uneven surface, even when extruded from a round-hole spinneret.

Acrylic Carpet Fiber Characteristics:

  • Outstanding wick ability and quick drying to move moisture from body surface
  • Flexible aesthetics for wool-like, cotton-like, or blended appearance
  • Easily washed, retains shape
  • Resistant to moths, oil, and chemicals
  • Dye able to bright shades with excellent fastness
  • Superior resistance to sunlight degradation

Advantages of Acrylic:

  1. Wool-like appearance
  2. Low moisture absorption
  3. Cleans easily
  4. Good stain resistance
  5. Resilient and bulky
  6. Resistant to moths and mildew
  7. Resistant to sunlight damage

Disadvantages of Acrylic:

  1. Not as strong as other synthetics
  2. Produced in short fibers and crimped
  3. Poor resistance to matting
  4. Stained by oil and grease

Olefin Carpet Fiber:
Olefin carpet fiber is strong, resists wear and permanent stains, and it is easily cleaned. It is notably colorfast because Color is added in the fiber production. It resists static electricity and is often used in both indoor and outdoor installations because of its resistance to moisture and mildew. It is used in synthetic turf for sports surfaces and in the home for patio and game rooms. Many Berber are made of Olefin.

Olefin fiber carpet
Fig: Olefin fiber carpet

Olefin is the next-best seller after nylon (about 80% of commercial carpet). These fibers are colorfast because the production process involves mixing polypropylene with dyes. Olefin works best in loop carpets such as Berbers. It is strong (resisting both crushing and abrasion), mildew resistant, moisture resistant, and easy to clean (bleach can be used safely in some cases). However, olefin can be easy to crush depending on the pile. This fiber is used in many artificial sport turfs.

Olefin Facts:

  • Fiber-forming substance of any long-chain, synthetic polymer composed of at least 85% by weight of ethylene, propylene or other olefin units
  • Offered as BCF or staple
  • Primarily sold as a solution-dyed fiber or yarn
  • Can be engineered for outdoor applications

Advantages:

  1. Solution dyed colors
  2. Good cover and bulk
  3. Abrasion resistance
  4. Inherent stain resistance
  5. Low static
  6. Favorably priced
  7. Resists fading

Disadvantages:

  1. Poor resilience
  2. Flammability rating typically lower than nylon

Applications:
Contract and residential. Medium to low price points. Also, dominant fiber in primary backing.

Polyester Carpet Fiber:
Polyester carpet fiber is noted for its luxurious soft “hand” when used in thick, cut pile textures. It has excellent color clarity and retention. Polyester is easily cleaned and resistant to water-soluble stains.

Polyester fiber carpet
Fig: Polyester fiber carpet

Polyester does not hold its fiber height under traffic and shifting weight as well as other carpet fibers. Polyester is luxurious, durable against abrasions, easy to clean, and resistant to water soluble stains. Polyester carpets cost less than wool and nylon.

Polyester Facts:

  • Made from terephthalic acid and ethylene glycol
  • Offered in BCF, but mainly staple form
  • Used in residential and some commercial applications

Advantages:

  1. Color clarity
  2. Colorfastness
  3. Resistant to water-soluble stains
  4. Noted for luxurious “hand”

Disadvantages of Polyester:

  1. Prolonged exposure to sunlight weakens fiber
  2. Grabs onto oil and grease

Wool Carpet Fiber:
Wool’s naturally crimped shape is the formation of millions of air pockets that act as insulation to help regulate room temperature and reduce energy bills. Also, Berber carpet is easy to clean and purifies your indoor air for up to 30 years from common contaminants like formaldehyde, nitrogen dioxide and sulfur dioxide by locking the contaminants deep in the core of the fiber.

Wool fiber carpet
Fig: Wool fiber carpet

Soft, yet resilient, this fiber can withstand the toughest treatment and still bounce back.

Fiber Facts:

  • Natural fiber
  • Inherent resilient property

Advantages:

  1. Prestigious
  2. High customer acceptance
  3. Pleasing hand
  4. Resilient
  5. Styling versatility
  6. Frame resistant
  7. Low “apparent soiling”

Disadvantages:

  1. Expensive
  2. High static charge
  3. Difficult to remove many stains
  4. Allergenic for some
  5. Variable quality
  6. Available only in staple
  7. Low abrasion resistance
  8. Not piece dye able

Applications:
Contract and residential. However not suitable for every construction.

Fibers used in the backing structure of Carpet:

Jute:
Jute is an ideal carpet backing fibre. It is relatively inexpensive and is relatively inextensible. A particular drawback, however, is the long supply route, mainly from the Indian sub-continent and the uncertainty of consistent supply. Jute is also liable to bacterial attack, particularly if wetted.

Jute yarn has been the most popular choice for the weft of woven carpets and many woven carpets continue to use jute yarn for this purpose. Jute is also frequently used as the ‘stuffer’ warp in Wilton carpets.

Woven jute fabric (Hessian) is frequently the secondary backing fabric of choice because of its low cost, good dimensional stability and natural appearance. Unreliable supply has, however, affected its popularity for many manufacturers.

Cotton:
Cotton yarns have traditionally been used as the warp yarns for woven carpets. Cotton fiber, in blends with synthetics, remains popular for this end use.

Polyester:
Spun yarns of high-tenacity polyester have been used in recent years as warp yarns in woven carpet but a more common use is as a cotton polyester blend in chain warp yarns.

Polypropylene:
Split film polypropylene yarns have been used as both warp and weft yarns in woven carpet production. In the form of nominal 1000 d’tex yarn as a cotton substitute for Axminster weaving polypropylene offered a less expensive alternative to cotton but led to lower weaving efficiency, since the abrasion of the yarns by the reed and other weaving components caused the yarn to fibrillate and entangle.

As a weft yarn, often pigmented to a natural jute color, polypropylene is used in weft yarns where high strength and comparatively low cost are advantageous. The yarn is less tension stable than jute but is unaffected by water and is not subjected to bacteriological attack.

Others:
Historically, because of jute shortages following the Second World War ‘kraft’ paper was used as a substitute. This yarn was effectively twisted strips of brown paper. Its use did not continue once jute became available again. Linen yarn has been used as the weft in some high-density 3-shot Wilton products necessitating a finer yarn of adequate strength.

References:

  1. Advances in Carpet Manufacture, 2nd Edition Edited by K. K. Goswami
  2. Textile Technology-An Introduction, 2nd Edition by Thomas Gries, Dieter Veit and Burkhard Wulfhorst
  3. Care and Maintenance of Textile Products Including Apparel and Protective Clothing By Rajkishore Nayak and Saminathan_Ratnapandian
  4. The Substrates — Fibres, Yarn and Fabrics By Mathews Kolanjikombil
  5. Textile and Laundry in Hotel Industry By D. K. Aggarwal
  6. https://en.wikipedia.org/wiki/Carpet
  7. http://www.madehow.com/Volume-2/Carpet.html
  8. http://www.carpetandrugpedia.com/Carpet_Manufacturing_Process.htm
  9. http://tlc.howstuffworks.com/home/how-is-carpet-made1.htm
  10. http://carpetinfo.co.uk/all_about_carpet/carpet_fibres.htm
  11. http://voices.yahoo.com/carpet-yarn-count-most-important-factor-choosing-1047463.html
  12. http://www.interiordezine.com/finishes/natural-carpet-fibers/
  13. http://www.bwmpl.com/carpet_yarn/woollen_yarn/carpet-yarn-making
  14. http://www.ehow.com/list_7606204_uses-carpets.html
  15. http://www.wisegeek.com/what-are-the-different-types-of-carpet.htm

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