quality control in textile

8/22/2019 Quality Control in Textile

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QUALITY CONTROL

IN

WET PROCESSING

PART I

PRETREATMENT PROCESSOF FABRIC

C. R. MADHU

Textile Processing Technology Department

R.C. Technical Institute, Sola, Ahmedabad, Gujarat


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QUALITY CONTROL

Quality in business, engineering and manufacturing

has a pragmatic interpretation as the non-

inferiorityorsuperiorityof something

also defined as fitness for purpose

Quality is a perceptual, conditional and somewhat

subjective attribute and may be understood

differently by different people

Quality control, or QC for short, is a process by

which entities review the quality of all factors

involved in production.
http://en.wikipedia.org/wiki/Pragmatichttp://en.wikipedia.org/wiki/Pragmatic


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There are five aspects of quality in a businesscontext:

1. Producing :- providing something.

2. Checking :- confirming that something has beendone correctly.

3. Quality Control :- controlling a process to ensurethat the outcomes are predictable.

4. Quality Management :- directing an organizationso that it optimizes its performance through

analysis and improvement.5. Quality Assurance :- obtaining confidence that a

product or service will be satisfactory. (Normallyperformed by a purchaser)


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TOTAL QUALITY MANAGEMENT (TQM)

Total Quality Management, is an approach that extendsbeyond ordinary statistical quality control techniquesand quality improvement methods

TQM is only one of many acronyms used to label

management systems that focus on quality CQI (continuous quality improvement)

SQC (statistical quality control)

QFD (quality function deployment)

QIDW (quality in daily work)

TQC (total quality control)

TQM is an integrative philosophy of management forcontinuously improving the quality of products andprocesses
http://en.wikipedia.org/wiki/Total_quality_managementhttp://en.wikipedia.org/wiki/Management_fadhttp://en.wikipedia.org/wiki/Quality_(business)http://en.wikipedia.org/wiki/Quality_(business)http://en.wikipedia.org/wiki/Management_fadhttp://en.wikipedia.org/wiki/Total_quality_management


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QUALITY CONTROLFOR GRAY FABRIC

Visual Examination for certain defects as stains,

mildew contamination, metallic impurities

These impurities may be carried out to trace backtheir nature and origin at the grey stage

This will help in taking suitable corrective action

during processing and to adopt preventive measureas well.


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EXAMINATIONUNDERULTRAVIOLET(UV) LIGHT

This may be provide the origin of a stain by its

characteristic fluorescence

Mineral oil :- Strong Violet/White Vegetable oil :- Yellowish

Metallic soap :- Yellowish

Fluorescent brightening agent :- Strong Violet/Blue

Mildew growth :- Yellow Metal stain :- Very dark area against a lighter background


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DETECTIONOF COPPER & IRON

Copper & Iron is likely to cause damage of cellulosic

fibres, due to catalytic effect in peroxide bleaching

Fe :- Potassium thiocynate/Potassium ferrocyanide test

Dilute HCl, Potassium thiocynate (Pink)

(10%)/Potassium ferrocyanide(10%) (Dark blue)

Cu :- Ashed smaple

Dissolved in dilute HCl & treated with Sodium

diethyldithiocarbamate followed by extraction withchloroform

Yellow colour indicate presence of Cu


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QUALITY CONTROLIN PRETREATMENT

PROCESSOF FABRIC

Process Test to be carried out

Desizing 1. Desizing efficiency

Scouring

1. Absorbency

2. Wax content3. Ash content

4. Cuprammonium test

Bleaching

1. Absorbency

2. Cuprammonium test

3. Whiteness

4. Yellowness

Mercerising 1. Barium activity number

Heat Setting 1. Boiling water shrinkage

2. Iodine absorption test


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DESIZING EFFICIENCY

Indian Standard No. 199, AATCC Test Method 79-1995

Sample is to be solvent extracted in a soxhlet with chloroform % Desizing efficiency

= % Original Size - % Residual Size X 100

% Original Size

Desizing efficiency comes90% :- Excellent

80 90% :- Satisfactory

below 80% :- Poor


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ABSORBENCY AATCC TS-018

Allowing a drop of water to fall from a fixed distance (2.5 cm)

to the fabric mounted on embroidery frame of about 6 inchdiameter.

Drop absorbency test

Drop absorbency of about 5 sec is generally considered as

satisfactory

Berdnt & Golob, Dugal et.Al. suggested methods for

hydrophobic fibre also by using C.I. direct Blue 86 and Black

disperse dyestuff.


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WAX CONTENT AATCC TEST METHOD 97-2009

Extraction of about 10 g sample with suitable

solvent (Chloroform for Cotton & Petroleum etherfor Polyester blend) in soxhlet apparatus.

Extracted sample is dried in oven at 105C

Amount of residue is expressed as percentage wax

content on the original weight of sample.

Chloroform

Lab. Oven


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ASH CONTENT AATCC TEST METHODS 78-1989

5 g of sample incinerated in silica crucible in a

burner followed by complete ashing in a mufflefurnace at about 700C fro 10 minute

Amount of ash is expressed as percentage of the

original weight of sample

Muffle Furnace

Silica Crucible


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CUPRAMMONIUM FLUIDITYAATCC TEST METHOD 82-2012

Determination of chemical degradation of cotton

Cotton is dissolved in cuprammonium hydroxide in Xtype viscometer at 20C

Internal volume:- 20 ml, filled with water & at bottom 0.7ml mercury is filled.

C = F1 X d1 X t1, ,

for liquid of known fluidity

where, C = Viscometer Constant

F1 = Fluidity

d1 = Density

t1 = time of flow Fluidity of cotton F = C/t

For bleached fabric F = 5 8

is satisfactory


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WHITENESS AATCC TEST METHOD 110-2011

This is attributed to the luminosity or freedom from

yellowness

It is measured by reflection of the specimen against

standard white (MgO)

In blue region

W = 100 (R670R430) Harrison

W = 430 (R670R430) Stephenson

In USA, Hunters coordinates

W = L3b HunterW = L + 3a3b Stensby


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BARIUM ACTIVITY NUMBERAATCC TEST METHOD 89-2012

Degree of swelling of cotton material during mercerization is

determined by B.A.N. test

3 g of specimen is extracted with carbon tetrachloride in soxhlet

2 g of specimen is transferred to a conical flask and 30 ml, 0.25

N Ba(OH)2 is added to it.

This mixture is allowed to stand for 2 hours.

From above mixture 10 ml of sample is titrated against 0.1 N HClusing phenolphthalein.

Blank determination is also carried out without specimen in flask.

BAN = [(a b)/(a c)] X 100

a = volume of acid required for blank

b = volume of acid required for mercerized specimen

c = volume of acid required for unmercerized specimen

A well mercerized cotton shows BAN in the range 125 135.


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SHRINKAGEIN BOILING WATER

AATCC TEST METHOD 135

Test was originally recommended by Du Pont

Blended fabric sample is marked in warp & weft

direction & then boiled in water for 30 minute.

% Shrinkage = [ ( Lo Lf) / Lo] X 100Lo = Original Length

Lf= Final Length

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polyester/cottonblend fabric shows

shrinkage within 1 %


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IODINE ABSORPTION TEST

For assessing degree of heat setting this test is carried out.

1 g sample taken in 250 ml stopper flask, 0.1 N 30 ml Iodine is

added to this flask & allowed to stand for 2 Hrs.

Sample is taken out and added in 50 ml chloroform, then 10

ml 0.1 N Sodium thiosulphate is added to this mixture

This mixture is titrated against 0.01 N Iodine solution using

starch as indicator.

Blank determination is also carried out.

Iodine Absorption (mg/g) = [ (X Y) X 0.01 X 127 ] / W

X = ml of 0.01 N Iodine required for blankY = ml of 0.01 N Iodine required for sample

W = Weight in g of sample

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