CARPET PILE FIBRES

The quality, performance and appearance of carpets are largely determined by the materials from which they are made. This applies both to the backing and to the pile, or face cloth.

It can be safely assumed that carpets made with high grade pile yarns will alson contain appropriately high quality materials in the backing. There is no point in using expensive backing for carpets containing cheap pile yarn.

The pile of most carpets is made of yarn secured to a backing, Pile Yarn is made from large numbers of individual fibres and filaments which have been combined by some means, such as spinning, into continious lengths.

Until relatatively recently all materials used in carpets were of natural origin, from animals or plants, today, domestic carpets contain a large proportion of man made fibres, or a mixture known as a blend of natural and man made fibres.

The structure and surface nature of each types of fibre gives it the various unique properties which are put to good use by the carpet manufacturer.



NATURAL FIBRES

WOOL

Wool is by far the most widely used natural fibre for carpet pile yarns, and has become accepted as the yardstick against which all other fibres are judged.

The properties of the fleece from different breeds of sheep vary considerably. Some wool is chosen for colour, others which are more crimped or waved for there greater resilience. Wool has enormous elasticity and can be bent and twisted again and again without breaking.

By blending together these different fibres, a variety of wool yearns can be produced to suit various requirements. In some cases as many as six different varieties of wool are used to produce a desired effect.

Wool is a hydrophillic fibre, which means it contains moisture. This allows cleaning fluid to gradually soak into the fibre swelling it making cleaning more effective, it also prevents the dry friction conditions necessary to create static, and assists in the fibres natural flame resistance.

Although the fibre attracts water it is covered with minute scales like roof tiles which help repel oily stains.

BENEFITS
- Easy to clean
- Retains its appearance well
- Soil hiding properties (dullness)
- Soft and warm texture
- Very resilient (springs back)
- Flame resistant (scorches)
- Hydrophillic (repels oils, attracts water)

DISADVANTAGES
- Relatively expensive (imported brands)
- Relatively inflexible supply
- Suscetible to insect and vermin attack (unless treated)
- Rots in certain environments (wet or humid)


ANIMAL HAIR (excluding wool)

Hair fibre is usually tough, rather course and fairly inexpensive, it is used mainly in the production of contract carpet tiles and doormats.

Although this natural fibre is a by-product of the meat trade, and freely available, many manufacturers are turning to the man made fibre polypropylene which is inexpensive, hygienic, plentiful, and appeals more to the increasing environmentally aware customers.


COTTON

Cotton, a vegetable fibre, is used for the chain warps and stuffer warps in woven carpets.

Although cotton is an inexpensive hard wearing pile fibre, it compresses and loses it's appearance quickly. It is therefore only found in inexpensive imported carpets, or easily washed bathroom rugs.


JUTE

Jute is a hard wearing vegetable fibre mainly used for the contruction of carpet backing. It is frequently blended with viscose fibres combining durability and softness for use in inexpensive cord carpet or matting.


SILK

Silk is obtained by unravelling the threads of the silk-worms cocoon. The fibres are strong, have good elastic properties, and resist friction, making them a particularly hardwearing pile yarn and very soft to touch.

In spite of its suitability, silk is very expensive and thus normally only used for high-grade Oriental carpets/rugs.



MAN MADE FIBRES

The Term made-made fibres is applied to all textile fibres not of a natural origin. They can be further seperated into two categories;

REGENERATED FIBRES which are processed from natural components, mainly cellulose found in wood pulp. (Viscose Rayon)

SYNTHETIC FIBRES which are chemically processed from carbon based petroleum and coal-tar. (Nylon, Acrylic, Polyester, Polypropylene)

All man-made fibres are made by melting solid chips and forcing or extruding them through the fine shaped holes in a nozzle called a spinneret.

This process produces continious strands of filaments, each about the thickness of a human hair. These filaments are solidified by cool air or by a chemical bath.

The solidified filaments (Tow) in their present form have little strength and are very elastic.

To form the characteristic durability of a man-made fibre the filaments are passed between differentially driven rollers which re-align the molecules and reduce the fibres diameter, this process also stretches the fibres two to three times their original length to remove elasticity.

Finally, the filaments are crimped which gives the fibre the bulk, body and texture which gives the required handle and resilience.

At this stage of the process a decision is taken whether the filaments are to be left in their continious state (almost 2 miles long) or chopped into snaller lengths known as Staple Fibre (8 - 10 inches long).

Chopping up the continuous filaments changes their chracteristics, by reducing its strength, but increasing its texture, giving a 'softer feel'.

A major benefit of man-made fibres is that stain releasing chemicals or coloured pigments can be introduced into the initial solution, or onto the loose filaments. This ensures the colour and stain protection remain constant throughout the life of the fibre.



NYLON (Antron, Celon, Enkalon, Timbrelle)

Introduced in 1938, its name is derived from its cities of origin (New York and London). Nylon or polyamide was the first synthetic fibdre to be used in carpet production and is still the most popular, with 80% of all carpets made up solely, or blends of, nylon fibre. Nylon is manufactured from crude oil.

BENEFITS
- High strength
- Excellent abrasion resistance (10 x that of wool)
- Easily cleaned & shampooed
- Low flammability
- Easy to dye

DISADVANTAGES
- Lower appearance retention than wool
- Tends to soil easily (more recent variants less so)
- Tends to melt locally
- Prone to static electricity in dry, warm atmosperes (the addition of carbon reduces this)



ACRYLIC (Courtelle, Draylon, Orlan, Acrilan)

Introduced to carpet manufacturing in 1957, these fibres are particularly noted for their soft texture. Acrylic is manufactured from coal-tar.

Acrylic is the nearest of the synthetic fibres in both appearance and characteristics to wool.

BENEFITS
- Soft Wool-like textures
- Less expensive than wool
- Good resilience and wearing properties
- Reasonable abrasion resistance
- Dyes brightly
- Easily cleaned

DISADVANTAGES
- Prone to soiling
- Lower appearance retention than wool
- More expensive than other man made fibres
- Tends to melt with heat. Highly flammable
- Colours can be over-brilliant in some applications



VISCOSE RAYON (Evlan, Supralan, Swelan, Darelle)

First developed in 1892, Viscose rayon was one of the first man-made fibres produced. It is manufactured from regenerated wool pulp.

BENEFITS
- Low price

DISADVANTAGES
- Generally inferior to wool in most respects, but suitable for many applications when blended with wool and nylon
- Soils and flattens
- Poor flammability
- Poor durability



POLYESTER (Dacron, Terylene, Trevira, Lirelle)

Introduced in 1946, the main application for polyester is in the long 'shag' pile luxury carpets. Polyester is manufactured from petroleum derivatives.

BENEFITS
- Soft light texture
- High abrasion resistance
- Easily cleaned
- High-lustre appearance
- Resists staining

DISADVANTAGES
- Poor pile recovery and flattening
- Can be difficult to dye
- Prone to static electricity in low humidity environments
- Expensive and difficult to produce



POLYPROPYLENE (Fibrite, Meraklon)

Developed in 1954 from the same family as polythene. Originally only used for backing materials, but now widely used for heavy duty needlepunch carpet, and other special purpose applications like bathrooms and kitchens. This fibre has now become the second most popular used in the carpet industry.

BENEFITS
- Good abrasion resistance
- Good soiling resistance
- Excellent staining resistance
- Easily cleaned
- Relatively Anti-static
- Rot Proof
- Inexpensive backing material
- Absorbs virtually no moisture

DISADVANTAGES
- Poor reiliance
- Low resistance to heat
- Course textile
- Not available in bright colours
- Produces stiff backings (hinders fitting)
- Can deform if heat seamed at too high a temperature
- Needs solution dyeing, limits colours
- Needs blending with other fibres unless it's being used for loop pile carpets



BENEFITS OF CONTINUOUS FILAMENT YARNS
- Stronger and more uniform diameter
- Won't pill or fuzz because there are no loose ends
- Economical as it doesn't break during tufting
- Harder wearing



BENEFITS OF STAPLE FIBRES
- Softer luxurious texture like many wools
- Can be blended with different coloured staples fibres for added contrast
- Can be blended with other fibres to combine characteristics used in 80/20 wool nylon blends
- Gives more volume for same weight
- Excellent for plush/cut-pile carpets



SYNTHETIC FIBRE TECHNOLOGY

Synthetic fibres have a great advantage over natural fibres in that they are not confined to the lengths, thicknesses and qualities that nature provides.

They can in fact be engineered to give the best charactistics for any particular type of application.

Originally, synthetic fibres, particularly nylon, suffered from two main criticisms, a high soiling rate, and a high level of static charge.

New generation fibres have since been developed to combat these problems.

Polymers have been specially modified to generate far less static, thus minimising the attraction and retention of dirt particles.

Flame retardant characteristics can also be engineered in this way.

Cross-sections can now be varied at the extrusion stage to improve the appearance and soil-hiding properties of fibres.