Non Wovens

Question 1

Some of the oldest as well as some of the most modern fabrics fall under the category of nonwoven fabrics.

Answer 1

These fabrics are made by bonding or entangling fibres by chemical, thermal or mechanical means. Traditional nonwoven fabrics include felt and tapa.

Question 2

felt

Answer 2

Felt was one of the first fabrics made by humans. It is usually made from wool, although other fibres can be added for interest. The manufacturing process of felt depends on the physical and chemical properties of wool. Felt is defined as a textile composed of fibres physically interlocked by the inherent felting properties of wool and produced by a suitable combination of mechanical work, chemical action, moisture and heat, but without weaving, knitting, stitching, thermal bonding or adhesives.

Felting makes use of the overlapping scales of wool. By applying moisture, heat, pressure, friction and agitation, the fibres become entangled and the scales interlock to form a thick layer of matted fibres. Felt has no warp, filling or selvage, and therefore no grain line. It will not fray or ravel and is therefore frequently used for hats, appliqué work or small soft toys. Felt has little tensile strength and practically no elasticity or draping quality.

Question 3

There are a number of fabrics that are similar in appearance to felt:

Answer 3

such as boiled wool, loden cloth and melton cloth, but they cannot be classified as felt because they are first woven or knitted and then shrunk or finished to look like felt.

Question 4

Tapa

Answer 4

Tapa, or bark cloth, is made by placing layers of bark from certain trees, usually the paper mulberry tree, on top of one another and then beating these to produce a web. Bark cloth is not only made in the Pacific Islands, as often stated, but also in Central Africa. Souvenirs such as place mats, small bags and wall hangings are sold in countries like Uganda.

Question 5

Modern nonwoven fabrics

Production

Answer 5

The production of modern nonwovens (sometimes called bonded fibre fabrics) started in 1942. The nonwoven process eliminates the yarn production process and makes the fabric directly from fibres. One of the advantages of nonwovens is the speed at which they can be manufactured. Fabric can be produced at a rate of about 100m/min, compared to about 2m/min for knits and about 1m/min for woven fabrics. Production is also more energy efficient and less labour intensive than weaving and knitting production.

Question 6

Nonwovens can be classified as

Answer 6

disposable or durable goods. Disposable nonwovens include nappies, nappy liners, “wet ones”, medical dressings, protective garments, wipes and filters. Durable goods include interfacing fabric (vilene), wadding or batting in quilts and duvets, mattress ticking, shoe linings and certain carpet tiles.

Question 7

Nonwovens Uses

Answer 7

Traditionally, nonwovens were not used to any great extent for apparel. Technical developments in polymers, nonwoven processing and fabric finishing, however, have led to improvements in hand and drape, colouration and durability and care properties, which have opened up possibilities for the use of nonwovens for apparel.

Question 8

Manufacture Raw materials

Answer 8

Most nonwovens are made from polyester or polypropylene fibres but, depending on the end use, polyethylene, rayon, nylon, polylactic acid (PLA) and natural fibres such as cotton and flax can also be used.

Question 9

Manufacture Web formation

Answer 9

A nonwoven fabric is a web of fibres that is held together is some way. The first stage therefore is to produce a web of fibres. Webs of staple fibres can be produced by dry-laying techniques. These techniques can produce carded webs in which the fibres are parallel in the lengthwise direction, or are laid in both lengthwise and crosswise direction, or are laid in a random fashion. A random laid web can also be produced by air-laying, in which the fibres are suspended in an air stream and then blown on to a moving belt where the web is formed. Webs can also be formed using other processes such as wet-laying, electrostatic-laying and spraying.

Webs of filaments extruded through a spinneret are produced in the spun bonded process. The filaments are laid on a moving conveyor belt to produce the web. The spinnerets can be rotated to produce different patterns; a jet of air can be used to entangle the filaments. In the melt-blown process, the extruded filaments are hit with a high velocity air stream which breaks the filaments into short lengths. These are then collected on a moving conveyor belt.

Question 10

Manufacture Web bonding

Answer 10

After the web has been formed it needs to be bonded in some way or another. Methods include mechanical bonding of which the best known are needle punching, where the fibres are intertwined using needles, and spun laced, where the fibres are entangled using high pressure water jets; chemical bonding where the fibres are bonded together with an adhesive or latex; and thermal bonding in which thermoplastic fibres are heated and melted slightly so that the fibres are stuck together.

Question 11

Speciality nonwoven fabrics

A number of nonwoven fabrics can be considered speciality fabrics:

Answer 11

The fusible nonwovens are well known to us as iron-on vilene. They are used for interfacing.
The film fabrics are used as shower curtains, cooking bags, grocery bags and rainwear.
Coated film fabrics are used for curtain backing (black out), shoe linings and luggage.
The artificial suede fabric, Ultra suede, is not really well known in South Africa, possibly because it is so expensive. It is available as the paw-pad fabrics used by bear makers when making artists’ teddy bears. The artificial suede fabrics available in South Africa are usually based on a knitted and not a nonwoven fabric.

Question 12

“The market for nonwoven products has experienced tremendous growth.” Give the reasons why you think nonwovens are produced and sold in increasing quantities.

Answer 12

The market for nonwoven products has experienced tremendous growth because of:
High production rates
Lower costs
Lower energy use
Production being less labour intensive
Widespread use for disposable and durable goods
Improvements in properties which has opened up the use of nonwovens for apparel

Question 13

What is the difference between melton cloth and felt?

Answer 13

Melton cloth is a woven fabric which is shrunk and finished to look like felt. Felt is composed of physically interlocked wool fibres produced by a suitable combination of mechanical work, chemical action, moisture and heat, but without weaving, knitting, stitching, thermal bonding or adhesives.

Question 14

Why can felt be made from wool and wool blends but not from 100% cotton?

Answer 14

Felt can be made from wool and wool blends but not from 100% cotton because wool has overlapping scales. By applying moisture, heat, pressure, friction and agitation, the fibres become entangled and the scales interlock to form a thick layer of matted fibres. Cotton fibre has no scales.

Question 15

List the different ways in which the web can be bonded during the manufacturing of nonwovens.

Answer 15

The web can be bonded during the manufacturing of nonwovens by the following methods
Needle punching
Spun laced
Chemical bonding
Thermal bonding

Question 16

In a table give the four types of speciality nonwovens and a use for each. Fusible nonwoven

Answer 16

Interfacing

Question 17

In a table give the four types of speciality nonwovens and a use for each. Film fabric

Answer 17

Shower curtain

Question 18

In a table give the four types of speciality nonwovens and a use for each. Coated film fabric

Answer 18

Shoe lining

Question 19

In a table give the four types of speciality nonwovens and a use for each. Artificial sued fabric

Answer 19

Teddy bears

Question 20

Other fabric construction processes

Answer 20

Weaving, knitting and nonwoven manufacture are the three main process for fabric production. Fabrics can also be produced by laminating, stitching, narrow weaving and plaiting (braiding), open mesh construction techniques (knotting and knitting), stitch bonding and tufting. We will examine these techniques in the following sections.

Question 21

Multicomponent fabrics

Answer 21

Multicomponent fabrics consist of more than one layer fabrics. Techniques for producing them include laminating (bonding) and quilting.

Question 22

Bonded and laminated fabrics

Answer 22

There are three basic ways of laminating. In foam bonding, polyurethane foam is used to bond two pieces of fabric together. A thick layer of foam contributes to the warmth and thickness of the textile. The second method involves sticking an appropriate thickness of foam to the back of a fabric (foam-backed fabric). The third method involves the use of an adhesive to join the layers of fabric. These fabrics are also known as bonded fabrics. Breathable, lightweight, waterproof fabrics can be made by laminating a membrane to a face fabric, using an adhesive. A woven fabric is often laminated to the inner side of the membrane. These multicomponent fabrics are used for all weather clothing.

When buying bonded or laminated fabrics, the consumer should make sure that the fabric layers are sealed together firmly and that the grain lines (where applicable) coincide. Particularly in the case of foam-backed fabrics, the foam is sometimes used to disguise the poor quality of cheap, inferior fabrics.

Question 23

Quilted fabrics

Answer 23

A quilted fabric consists of two or more layers of fabric joined by stitching. Traditionally, quilted fabrics consisted of three layers: the face fabric (called the top) that was often pieced (patches of fabric sewn together); the batting or wadding in the centre (nowadays a polyester-bonded fibre fabric, but traditionally a wadding of cotton or woollen fibres); and a backing fabric. The layers can be joined by hand stitching, by knotting a piece of thread or string through all the layers or by machine stitching. Today quilted products can also be produced by chemical quilting or ultrasonic bonding.

Question 24

Narrow fabrics

Answer 24

Narrow fabrics are produced by weaving and braiding. Generally, they are less than 45 cm in width and the edges of the fabric are an essential feature of the fabric.

Question 25

Narrow fabrics: Woven narrow fabrics

Answer 25

Woven narrow fabrics include end products such as seat belts, industrial webbing, belting, binding, ribbons and tapes such as the tapes used in zippers, as well as woven labels with the manufacturer’s name, size or care instructions for garments.

Question 26

Narrow fabrics: Braided fabrics

Answer 26

Braids are not manufactured on a weaving loom with a definite warp and weft, but consist of three or more yarns plaited together. Braids can be flat or circular. Braids have many industrial uses, but the end products we are most likely to be familiar with include shoelaces, insulation for electric wires, parachute cords and decorative trims.

Question 27

Open-mesh constructions

Answer 27

Open-mesh constructed fabrics include net, lace and embroidery.

Question 28

Open-mesh constructions: Net

Answer 28

Nets are open-mesh fabrics, originally made by knotting the yarn at each point of inter-section. Today most nets are made on tricot or raschel knitting machines. Tulle is a type of fine net, often used in bridal veiling.

Question 29

Open-mesh constructions: Lace

Answer 29

Lace can be described as an openwork fabric consisting of a network of yarns formed into intricate designs. Lace fabrics dating back to 2 500 BC have been found. The first lace-making machine was built in 1808 by John Heathcote. The first Leavers machine was built in 1813, and in 1837, the Leavers brothers improved their machine by incorporating the Jacquard loom principle.

Basically the Leavers lace-making machine used today remains the same as it was in 1837. It is the most complicated piece of textile equipment in the world. Owing to the high cost of producing lace on these machines, however, a relatively high proportion of laces are made on raschel knitting machines.

Question 30

Open-mesh constructions: Embroidery

Answer 30

Embroidery consists of the application of yarn or thread to produce a design on an existing fabric. The Schiffli embroidery machine was developed in the mid-1800s. Embroidery that resembles lace can also be manufactured by embroidering a special fabric that dissolves easily in water or other chemicals. The base fabric is dissolved leaving only the embroidered pattern behind.

Question 31

Stitch-bonded fabrics

Answer 31

Stitch-bonded fabrics are also known as sew-knit or stitch-through fabrics. They are multicomponent fabrics. The one component may be of a layer of warp yarns placed over a layer of weft yarns (not interlaced), or a fibre web or batt, or yarns. The other component is a stitching yarn which binds the other component together. Owing to the speed with which stitch-bonded fabrics can be produced, it is an economical way of constructing fabric. Examples of stitch-bonded fabrics are malimo, a flat fabric, and malipol, a pile fabric.

Question 32

Tufted fabrics

Answer 32

Tufting is a process of making pile fabrics by punching extra yarns into an already woven fabric. The pile can be cut or left uncut. The back of the base fabric can be coated with latex to hold the tufts in position. Ninety per cent of all carpets produced today are made by the tufting process.

Question 33

What is a multicomponent fabric?

Answer 33

Multicomponent fabrics consist of more than one layer fabrics. Techniques for producing them include laminating (bonding) and quilting. Bonded and laminated fabrics

Question 34

Differentiate between a laminated and a quilted fabric.

Answer 34

Laminated or bonded fabric are produced by bonding fabrics together using foam or adhesive. Quilted fabrics can be bonded by sewing, knotting, chemical or ultrasonic bonding. Laminates include two fabrics bonded by polyurethane foam, foam-backed fabrics, and fabrics bonded by adhesives. Traditionally, quilted fabrics consist of three layers: a face fabric, a middle batting or wadding, and a backing fabric.

Question 35

How would you identify a braided fabric?

Answer 35

Braids consist of three or more yarns plaited together. The yarns cross one another in such way that a diagonal formation is created. Braids can be flat or circular.

Question 36

What is the difference between net, lace and embroidered fabric?

Answer 36

Nets are open-mesh fabrics, made by knotting the yarn at each point of inter-section or by knitting on tricot or raschel knitting machines. Lace is an openwork fabric consisting of a network of yarns formed into intricate designs. Laces are made on lace-making machines; less expensive types are produced on raschel knitting machines. Embroidery consists of the application of yarn or thread to produce a design on an existing fabric. Embroidery that resembles lace can also be manufactured by embroidering a special fabric that dissolves easily in water or other chemicals. The base fabric is dissolved leaving only the embroidered pattern behind.

Question 37

What is the advantage of a satin weave over a closely woven plain or twill weave? What is the disadvantage?

Answer 37

Satin weave fabrics often have higher tearing strength because they have long floats which allow easy slippage of the yarns. The disadvantage is that they are generally less strong.

Question 38

For small children who play vigorously outside, would warp or weft knits be the best?

Answer 38

Warp knit would be better because weft knits are subject to runs when a yarn is broken and weft-knit fabrics can be easily distorted because the loops can be made to slip and alter shape.

Question 39

Which construction methods will result in garments that are easier to maintain, and which in garments that are harder to maintain?

Answer 39

Fabrics with long floating yarns, or those constructed from fancy yarns, can be damaged during cleaning. Fragile fabrics such as laces may require special handling and nonwoven fabrics may require specialised cleaning methods. Sheer leno weave fabrics are easier to maintain than sheer fabrics of plain weave. Knitted fabrics may need only a minimum of ironing, but may require reshaping to retain size and appearance after laundering.