25 textile testing methods

BREAKING STRENGTH• Mainly used for woven fabric because the tests are unidirectional and woven fabrics have unidirectional yarns.. • Breaking strength can also be used to test the effe

TEXTILE TESTING

METHODS

Fabric testing is an important segment of the textile industry We can easily detect the faults of machinery and materials during test of textiles.

Textile standards: Standard is a prescribed required level of performance of material These standards are:

• NFPA: National Fire Protection Association

• ANSI: American National Standard Institute

Standardization

INTRODUCTION

Cotton fiber is a single

elongated cell

Under a microscope, cotton

fiber looks like flat, spirally

twisted ribbon-like tube with

rough granular surface

Mercerized cotton does not

have natural twist The finishing

straight, smooth and round with

a shining surface

Microscopic view of cotton

Wool fibe r has irregular,

roughly cylindrical, multi

cellular structure with tapered

ends

Under a microscope, three

basic layers are shown-

e pide rmis (outer layer), cortex

(middle layer) and medulla

(inner layer)

Medulla is seen only in coarse

and medium wool fibers and

that too under a highly powerful

microscope

MICROSCOPIC VIEW OF WOOL

Line n fibe r, under a

microscope, looks like having

multiple sided cylindrical

filaments with fine pointed

edges

The filaments show nodes at

intervals

It, in fact, looks like a bamboo

stick having joints that results

into a little unevenness

Microscopic view of

linen/flax

• Silk fibers are straight and

smooth.

• Raw silk fiber, composed of two

filaments, has elliptical shape

under the microscope

• The two fine and lustrous

filaments are shown clearly

looking like transparent rods with

triangular shape.

• Wild silk or tussah fiber has

different appearance than the

cultivated silk It is flattened,

coarse, thick and broader fiber

having fine, wavy lines all across

its surface whereas cultivated silk

is narrower fiber with no marks on

it.

MICROSCOPIC VIEW OF SILK

• Polyester (aka Terylene ) is a category of polymers which

contain the ester functional group in their main chain.

• Generally, polyester fibers are smooth and straight and the cross-section is round.

• With various finishing processes, its appearance changes in context of texture and luster.

MICROSCOPIC VIEW OF POLYESTER

The basic microscopic appearance is generally fine,

round, smooth, and translucent

Sometimes it has shiny appearance If it looks dull, it will also be dotted under the microscope. 

It is also produced in multilobal cross-sectional types

MICROSCOPIC VIEW OF NYLON

BREAKING STRENGTH

• Breaking s trength is the force required to

break a fabric when it is under tension (being pulled).

• Breaking longation is the increase in length

that has occurred when the fabrics breaks.

BREAKING STRENGTH

• Mainly used for woven fabric because the tests

are unidirectional and woven fabrics have unidirectional yarns.

• Factors that produce a strong fabric include

fiber content, yarn size and type, weave, and yarns per inch.

• Breaking s trength is expressed in pounds

and the elongation is expressed as a percent

and in both cases a number of warp tests and weft test are performed

IMPORTANCE OF BREAKING STRENGTH

TEST

• Breaking strength is important in various end

uses such as automotive safety belts, parachute harness and pants.

• Breaking strength can also be used to test the

effects of destructive forces upon a woven fabric including sunlight, abrasion, laundering etc.

TEARING STRENGTH

Te aring s tre ng th is the force required to

continue a tear or rip already stated in a fabric.

• This test is used mainly in

woven fabrics because the test

is unidirectional and woven fabrics have unidirectional yarns.

• A number of tear strength test

is carried out and the average

is taken to determine the tear strength.

• Tearing strength is expres s ed

either in po und s o r g ram s

BURSTING STRENGTH

Burs ting s tre ngth is the amount of pressure required to rupture a fabric.

• In this test, the testing force is applied radially and not in one

direction as in breaking or tearing strength tests.

• Fabrics like knits, felt, non woven, lace and netting are usually tested in this manner because these fabrics either do not have yarns or yarns are not in any given direction.

• The bursting strength is expres s ed in pounds

PILLING PROPENSITY

Pilling is the formation of small balls of fibres called pills

on the surface of the fabric

• Pilling occurs only when there is

rubbing or an abrasive action on the surface of the fabric

• Pilling usually occurs during

normal wear and also while clothes are in the dryer

• Evaluation should be made taking

into account the size, number, and visibility of the pills as well as the type and degree of other surface change.

PILLING PROPENSITY

After each test, each of the specimen is first evaluated for pilling

usually on a 5-4-3-2-1 pilling s cale , then surface appearance is

evaluated both for colour change as well as for fuzz.

An average of ratings is usually taken as a result.

Air permeability is expressed as cubic

fe et pe r s quare foot of fabric at a stated pressure differential between two surfaces of fabric

VARIABLES WHICH AFFECT AIR

PERMEABILITY

Fiber co nte nt : more crimp, lower air

permeability.

Yarn Twis t: less twist, less air permeability.

Yarn s ize : heavier yarns, lower air permeability.

Fabric Thic kne s s : thicker fabric, lower air

permeability.

Multiple laye rs : more layers, lower air

permeability.

Fabric yarns per inc h or s titc hes pe r inc h:

greater density, lower air permeability.

resistance so it does not last long when used for lining in

jackets and coats

Garments that are made from fibres that possess both high breaking strength and

abrasion resistance can be worn often and for a long period of time before signs of physical wear appear

CHEMICAL TESTING

• COLORFASTNESS PROPERTIES.

• CHEMICAL SOLUBILITY TEST

COLORFASTNESS

PROPERTIES

• Used to determine the resistance of dyed or

printed fabrics to color change under various

conditions.

• There are various reasons as to which a fabric changes colors like sunlight, pollution gases, abrasion,

perspiration, dry cleaning etc

• A fabric that experiences little color alteration when

exposed to a fading force is said to have a good

colorfastness while if the color does not hold, then the fabric has poor colorfastness

COLORFASTNESS

PROPERTIES

There is a scale from 5 to 1 for evaluating

colorfastness.

Class 5 means no shade change and class 1 means

very great shade change

Problem persists with deeper colors like red rather than pastel colors

Colorfastness to light is rated on L9 to L1 scale with L9 being the best rating and L1 the worst

DIFFERENT TYPES OF COLORFASTNESS TESTS.

COLORFASTNESS TO SUNLIGHT

• Dyed fabrics when exposed to sunlight

will in time fade or change color This

property is called as colorfastness to

sunlight.

• Many apparels are tested up to 40

hours because certain fabrics have to

resist the fading effect of the sun to a

much greater degree.eg men's suit.

• Drapery fabrics are usually tested for 8

hours whereas canopy fabrics for 160

hours.

COLORFASTNESS TO SUNLIGHT

• The device used is called a weather- ometer.

• A combination of artificial light, heat & moisture is used

• the no of hours that the specimens are in the machine should be indicated

• This machine offers accelerated weathering and light

fastness test for chemicals

COLORFASTNESS TO WASHING

• A no of variations are followed to test colorfastness to washing because there are differences in washing procedures

IMPORTANT CONSIDERATIONS BEFORE

WASHING

• The washing temperature

should have a great affect on

colors.

Often the dye is loosened from

fabrics by the action of hot water.

IMPORTANT CONSIDERATIONS BEFORE

WASHING

• Mechanical action.

Mechanical action subjected to

laundering should also be included in

washing test.

• Proportion of liquid.

The proportion of liquid to the amount of material washed is important because if volume of liquid is too high, the material would just float without the squeezing Whereas in smaller amount there would be twisting action.

COLORFASTNESS TO CROCKING

• Crocking is the transference of

color by rubbing from one

colored textile material to

another

• Wet fabrics will crock more easily than dry ones because the moisture present assists in

removing the dye

• Similarly, printed

fabrics often will crock

more easily than dyed

fabrics because in

printed fabrics the dye

is on the surface than

inside the fabric

• Dark shades are more likely to crock than light colors because there is more dye in dark colors than light ones

COLORFASTNESS TO CROCKING

• The arm is rotated back & forth causing the white

crock test cloth to rub against the specimen

COLORFASTNESS TO CROCKING

• The arm is rotated back & forth causing the white

crock test cloth to rub against the specimen

Colorfastness to frosting

•Frosting is a localized color change produced by a

relatively severe, localized flat abrasion action Eg

back pocket of a pair of trousers.

•Fabrics with poor dye penetration will fade quickly

from abrasion as on the surface will wear, leaving a

very little color.

•Blended fabric can change colors if each fiber has

different abrasion resistance.

•Eg in a dark grey fabric, the black cotton will

abrade more quickly than a white polyester fabric,

developing a light grey color.

•The device used is a surface Abrader.

Colorfastness to perspiration

•Perspiration may change the color of a fabric.

•Three things may take place :

1 color change of the dyed fabric.

2 Loosening and uneven repositioning of color on

colored fabric.

3 Staining of material next to the colored fabric.

• Perspiration maybe slightly acidic but through

bacterial action, it becomes alkaline The dye

may get affected by both.

•. The device used is the perspiration tester.

• a slightly acid solution on one cloth & alkaline on

another is used Both specimens are tested.

• The one with the most color change is used to

represent the fabric and its class rating is used as

a result.

Colorfastness to dry cleaning

•Color may change due to dry cleaning too.

•This test indicates what will happen to the

color of textile materials after repeated

commercial dry cleaning.

•Perchlorethylene is used in the test:

•Commonly used dry cleaning solvents.

•It is slightly more severe in solvent action.

•A color that may get affected by

perchlorethylene will not get affected by

Stoddard solvent (petroleum base).

•Device used for this test is the launder-

ometer.

•Dry cleaning solvent instead of water is used as

liquid.

Colorfastness to burnt gas fumes

•Lastly, color changes due to the presence of nitrous oxide in the atmosphere.

•Acetate is the most susceptible to this gas.

•When disperse dye is combined with acetate ,

severe color changes take place.eg blue which

•The source of burnt gas fumes is a Bunsen burner

placed at the bottom of the instrument.

Chemical test

•In these types of tests , chemicals are used as a part of the test procedure.

•the specimen is dissolved in the

chemical to check its solubility

•The test include :

•Colorfastness

•Fiber identification using the solubility test.

Chemical solubility

test

COTTON & FLAX:

They can be differentiated by observing their

longitudinal appearance with a microscope.

SULPHURIC

SULPHURIC

SILK & WOOL:

Polyester:

Acetate :