working properties of fibres fabrics and testing

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 Strength
 Extensibility
 Elasticity
 Fineness
 Electrostatic
charge
 Lustre
 Thermal
insulation
 Flammability
 Moisture absorption
 Shrinkage
 Very
strong – polyester, polyamide
 Good strength – elastane, acrylic, silk, cotton
(*stronger when wet*), linen
 Medium strength - wool
 Low strength – viscose (*significantly lower
than cotton* and also poor wet strength),
acetate
 Elasticity
is the property which allows a fibre
to recover to its length after it has been
extended.
 Very good – wool due to natural crimp in the
fibre; silk; polyester; polyamide; elastane
(lycra); acrylic
 Poor – cotton (creases easily); linen (creases
badly); viscose (creases easily)
 Measured
in units of tex or decitex (dtex).
The smaller the number the finer the fibre.
 Remember with tights that a 40 denier tight
is thicker than a 10 denier
 Textile fibres can be classified into coarse,
fine and microfibres
 Microfibres
are mainly synthetics with a
linear density of less than 1 dtex.
 Finer fibres make for softer, denser and more
comfortable fabrics with better drape.

Microfibre is fiber with strands less than one denier.
Microfiber is the perfect blend of polyester and
polyamide. Fabrics made with microfibers are
exceptionally soft and hold their shape well. When high
quality Microfiber is combined with the right knitting
process, it creates an extremely effective cleaning
material. This material can hold up to seven times its
weight in water. They are also used for some cleaning
applications, because of their exceptional ability to
absorb oils.
 sythnetic
fibres generally have an
electrostatic charge due to their low
moisture absorption. Remember that when
you wear a polyester skirt and nylon tights
that you often get static cling and the skirt
“rides” up your legs.
 Natural and regenerated fibres rarely have
an electrostatic charge because the moisture
present conducts the charge away.
 Silk
has a typical lustre due to the trilobal
cross section of the fibre
 Viscose, can range from high lustre to matt
depending on the cross section and the
addition of delustrants.
 Polyester and polyamide can range from high
lustre to matt depending on the cross section
and the addition of delustrants.
 Cotton can be given lustre by a treatment
with caustic soda called mercerizing that
makes the cross section more circular
meaning that light can be reflected.
 Warm
to wear – wool, acrylic,
 Cool to wear – cotton, silk (*but also provides
good insulation and is used in thermal
underwear), linen,
 low warmth - viscose, acetate, polyester
unless texturised yarns, polyamide unless
texturised yarns, elastane (but also used in
blends)
 Very
flammable and ignite with a naked flame–
cotton, linen, viscose
 Wool – does not burn easily and is used for
protective clothing
 Synthetic fibre tend to shrink away from the
flame and melt
 A blend of cotton/polyester burns dangerously as
the cotton ignites and the polyester melts
creating a “scaffold” effect”




Is measured as the standard moisture regain
(SMR%) of a fibre. The test is carried out in a
special room at 20ºC and at 65%RH (relative
humidity)
Synthetic fibres have poor moisture absorption
(remember high static). They are hydrophobic and
fast drying.
Natural fibres have good moisture absorption
properties (low static).
Cotton can absorb up to 20% of water vapour
without feeling wet.



Wool is hygroscopic – it can absorb up to a third of
its weight in water vapour without feeling wet!
Water vapour is absorbed, but water droplets are
repelled – this behaviour is known as hydrophobic!
Silk, like wool it can absorb up to one third of its
weight in water vapour.
Viscose is slightly more absorbent that cotton. Due
to its absorbent nature viscose is used in sanitary
wear, nappies, household wipes etc.
Strength
 This is the degree to which a fabric will resist strain.
 A strong fabric will not tear easily and will have a high
tenacity value.
Durability
 This means the fabric does not wear out easily.
 It is resistant to abrasion, rubbing and friction.
 Chemicals in detergents and anti-perspirants may
reduce durability.
 Ultra-violet light may break it down.
Elasticity
 This is the ability a fabric has to stretch. The fabric:
 has the ability to recover to its original shape and size
 Easily sheds creases and crushing
 gives added comfort in wear
 is resilient and recovers well after stretch.
Flammability
 This is the degree to which a fabric will catch fire or burn.
 Non-flammability may also be achieved by a special chemical finish.
Thermal qualities  Warmth/thermal insulation
 Fibres trap air, preventing passage of heat away from body.
 Construction of knitted fabric laminates and membranes lend
themselves to trapping air and preventing passage of heat away from
the body.
Crease resistance
 This means the fabric:
 sheds creases easily
 keeps good appearance
 requires little ironing/tumble drying.
 Crease resistance may be improved by the addition of a chemical
finish.
Absorption/absorbency
 This means the fibre can readily soak up/absorb water/moisture. The
absorbency of a fibre is measured as its SMR% (standard moisture
regain).
 The fibres are termed hydrophilic, water loving. For example, cotton
and viscose.
 In contrast, some fibres are naturally water repellent.
 These fibres are termed hydrophobic, water hating. For example,
polyester, nylon and acrylic.
 Polyester is so hydrophobic that it attracts and absorbs fats, oils and
greases. It is termed olephilic, oil loving. This can make it difficult
to remove grease stains.
Stretch/elasticity –
 This is the ability a fabric has to stretch. The fabric:
 has the ability to recover to its original shape and size
 Easily sheds creases and crushing
 gives added comfort in wear
 is resilient and recovers well after stretch.
Formability
Easy care
 This means the fabric can be easily laundered without damage. The fabric:
 allows soiling to be removed easily
 is not damaged by detergents
 does not lose colour when washed
 does not lose shape when washed
 does not shrink when washed
 dries easily/quickly
 can be tumble dried
 requires little ironing
 does not require special care/dry cleaning.
Handle
 this means how a fabric feels to the touch and is subjective.
Fabric can be described as having a crisp hand, firm hand, soft
hand, slippery hand, silky hand etc. Silk has a characteristic
“scroop”
Drape
 this means how a fabric falls, hangs or drapes. Drape can be
recorded in laboratory tests.
Weight
 this is the weight of the fabric usually measured as gm2, but
sometimes measured in linear metres. Denim is traditionally
weighed in oz, such as a 12oz denim for jeans, a 8oz denim for
shirting.
Pattern repeat
 this applies to fabric that can be either a printed woven or
knitted fabric (i.e. floral print) or yarn dyed woven (i.e.
unbalanced check) or a fancy weave (i.e. jacquard)
Directional pile - also refer to pile weave/knits
 Pile runs in one direction.
 Fabric has a rich, luxurious appearance and feel.
 Fabric appears lighter if pile runs down.
 Fabric appears darker/richer if pile runs up.
 Pile is easily marked/flattened by water/staining
 As the surface of the fabric is raised, extra consideration should
be given to layout, cutting, assembly and finishing to avoid
disturbing the pile.
Examples
 Carpet
Chenille Corduroy
 Fake fur
Fur fabrics
Novelty pile fabrics
 Terry towellingVelour
Velvet
 Velveteen
Nap
 Direction of pile/brushing
Texture
 this refers to the surface texture of a fabric. Fabric such as
knitted fleece can have a wool fleece like texture.
Brocade and jacquards have their texture woven into the
fabric as their design/pattern.
Lustre
 is used to describe the sheen/shine of a fabric
 Traditionally synthetic fibres/fabric are shiny, however,
delustrants can now be added to the synthetic chip/molten
polymer to make the fibres matt in appearance. In industry
a de-lustred fibre would be referred to as being semi-dull
or full-dull.

In industry testing of materials to determine appropriate
properties in relation to chosen end use is carried out a various
stages of the process.

Raw materials/fibre

Yarn

Weaving/knitting/non-woven

Griege fabric -

Dyed/Printed/Finished fabric

Fibre composition

Fabric performance

Product performance

Raw materials/fibre would be tested to ensure that quality
standards are met. If you are a spinner of woollen yarn then you
need to know that you have been supplied with 100% wool fibre
from a specific breed of animal

Yarn will be tested to ensure that quality standards are met. The
strength and perhaps elasticity and extension of the yarn will be
tested. The yarn will be checked to see that it has the correct
number of twists per cm etc.

Weaving/knitting/non-woven. During the fabric manufacuturing
process that fabric will be tested to check that it is the correct
weight per gm2. The strength of the fabric might be tested at this
stage. Poor strength could be an indicator that there is a problem
with the greige fabric.

Fibre composition of a blend, mixture will need to be tested to
determine if the fabric meets the standard. Luxury fibres such as
cashmere (Nobel fibres), are also tested to ensure that the
consumer is not deceived with an inferior fibre.

Dyed/Printed/Finished fabric. The fabric mill will test the
performace of the fabric to deterime if it meets the correct
quality standards. Common testing at this stage will include

Strength

Shrinkage/stability

Colourfastness to washing

Colourfastness to rubbing

Any key promotional claims such as water repellency, waterproof,
breathability, crease resistance, wrinkle free, stretch,

Fabric performance. The garment maker might carry out their
own testing to determine if the agreed standard of performace
has been met. Failure for the bought fabric to met the standard
can result in orders being cancelled.

Product performance. Finished products are also tested. By law
Childrens nightwear and upholstery must be tested for
flammability. Promotional claims must also be tested, such as a
product being promoted as “waterproof.”
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