This document discusses jute fiber and its production process. It provides details on:
1. The types of jute plants used, white jute and tossa jute. Jute requires a warm, humid climate for cultivation.
2. The jute production process which involves harvesting, retting, stripping fibers from stalks, washing, drying, grading, and baling.
3. The chemical composition and properties of jute fiber which is primarily cellulose. Pretreatment processes like scouring and bleaching are used to remove impurities before dyeing or finishing jute fabrics.
2. Introduction
The technical jute fiber consists of strands i.e. bast bundle fiber assemble in
parallel manner with overlapping to producefilaments throughoutthe length of
the stalk. It is also physically coarse, meshy, harsh, and irregular in length and
diameter. On account of their properties, jute is used for making traditional
products such as ropes, cords, hessian, sacking, and carpet backing cloth (CBC)
etc. Jute fiber bundle contains cells or ultimate fibers which are joined together
with natural cementing materials as lignin and hemi-cellulose etc. Similarly each
ultimate fiber is composed of a large number of smaller units known as fibrils
and these are arranged in right-handed spirals. The fibrils are again made up of
molecular chains, closely held together. These are known as micells. Though
lignin and other non-cellulosic materials are abundant in the middle lamella,
they are also found in other parts of the cell wall.
Theusesof jutematerials aregraduallydecreasing dueto keen competition from
synthetic products. So, non-traditional and value added products are shout in
wider scale. The presence of wax, pectin and mineral matters in jute creates
some problems in dyeing, printing and finishing. For these reason various
treatment like scouring, mercerizing and bleaching are required for better
dyeing, printing and finishing of jute and juteproducts for diversified useof jute
products.
Simultaneously the pretreatment or chemical modification and after treatment
is essential for proper dyeing and printing. Anhydrous liquid ammonia
penetrates through cellulose relatively easily and reacts with the hydroxyl
groups after breaking the hydrogen bond that swelling and decrystallization of
ammonia on cellulose formed two complexes such as cellulose-II and cellulose-
III isobtained when ammonia is allowed to evaporateand cellulose-I is obtained
whenammonia is washedwith water.Inrecentyears,liquid ammonia treatment
has been used to develop a new process called "Prograde" to produce superior
3. quality sewing threads with improved strength and luster by J. & P Coats ltd.,
U.K. Similarly, a process of liquid ammonia treatment of fabric has been
developed by TEDECO, Norway, and details of the process are described by
Skaathun.Yarn of differentcotton varieties treated byProgradeprocessshowed
40%to 100%increasein strength aswell as improved whitenessand dye affinity
etc. Liquid ammonia processing is cheaper than conventional mercerization.
after breaking the hydrogen bond that swelling and decrystallization of
ammonia cellulose formed two complexes suchas on cellulose-11 and cellulose-
III isobtained when ammonia is allowed to evaporateand cellulose-I is obtained
whenammonia is washedwith water.Inrecentyears,liquid ammonia treatment
has been used to develop new process called "Prograde" to produce superior
quality sewing thread with improved strengthand luster by J. & P Coats ltd., U.K.
Similarly, a proces of liquid ammonia treatment of fabric has been developed by
TEDECO Norway, and details of the process are described by Skaathun. Yarn
different cotton varieties treated by Prograde process showed 40% to 100
increase in strength as well as improved whiteness and dye affinity e Liquid
ammonia processing is cheaper than conventional mercerization.
Ithas been found that different physicochemicalproperties of raw jute fabr are
not so good. These properties of jute and jute products can be improved
different treatments. For these reasons different treatments of fabrics were
donethis study,this workis undertaken to improvethe physicochemicalproper
of dyed jute products.
What is jute ?
Jute is a long, soft, shiny plant fiber that can be spun into corse, strongthreads.
producefromplants in the genus Corchorus, which seefor botanicalinform and
other uses. Jute is one of the cheapest natural fiber and is second only to c in
amount produced and variety of uses. Jute fibers are composed primarily plant
materials cellulose and lignin.
Jute is called in different names in differentparts of the world. Forinstancefiber
is often called Hessian fiber, jute fabrics are also called Hessian clot jute sacks
are called Gunny Bags in some European countries. The fabric from jute is
popularly known as Burlap in North America. InSpanish, jute is Youte and jute
fabrics are called Arpillera
4. TYPES OF JUTE
White Jute (CorchorusCapsularis)
Several historical documents during the era of Mughal Emperor Akbar (1542
1605) state that the poor villagers of India used to wear clothes made of jute.
Simple handlooms and hand spinning wheels were used by the weavers, who
used to spin cotton yams as well. History also states that Indians, especially
Bengalis, used ropes and twines made of white jute from ancient times for
household and other uses.
Tossa Jute (CorchorusOlitorius)
Tossa jute (Corchorusolitorius) is an Afro-Arabian variety. Itis quite popular for
its leaves that are used as an ingredient in a mucilaginous potherb called.
molokhiya, popular in certain Arab countries. The Book of Job in the Hebrew
Bible mentions this vegetable potherb as Jew'smallow. Tossa jutefibreis softer,
silkier, and stronger than white jute. This variety astonishingly showed good
sustainability in the climate of the Ganges Delta. Along with white jute, tossa
jute has also been cultivated in the soil of Bengal from the start of the 19th
century. Currently, Bangladesh is the largest global producer of the Tossa jute
variety.
Jute cultivation
Jute is a rainy season crop, sown from March to May according to rainfall and
type of land. It is harvested from June to September depending upon whether
the sowings are early or late.
The jute plant's fibres lie beneath the bark and surrounded the woody central
part of the stem. To extract the fibres from the stem, the process is carried out
in the following
5. Climate And Soll Condition
Jute requiresa warmand humid climate with temperature between 24°C to 37°
C. Constant rain or water-logging is harmful. The new gray alluvial soil of good
depth, receiving salt fromannual floods, is best for jute. Flow ever jute is grown
widely in sandy loams and clay loams.
Sowing Of Jute
Sowing of jute in midlands and high lands starts with showers in March or April
and continues till early Junein the westernpart of the jutebelt. Compostor firm
yardmanure,PhosphorusandPotash,Nitrogenfertilizers areused asa fertilizer.
Interculturing is essential in the early stage. Pasts are also require for plant
protection.
Harvesting
Jute is harvested any time between 120daysto 150dayswhen the flowershave
been shed, early harvesting gives good healthy fibers. The plant from 8 to 12
feet high are cutwith sticklesat or closethe groundlevel. Inflooded land, plants
are up rooted. The harvested plants are left in field for 3 days for the leaves to
6. shed. The stems are then made up into bundles for steeping in water. Steeping
is carried out immediately after harvest.
The Fiber Extraction
The jute plant's fibres lie beneath the bark and surrounded the woody central
part of the stem. To extract the fibres from the stem, the process is carried out
in the following stages:
Retting
Retting is a process in which the tied bundles of jute stalks aretaken to the tank
by which fibres get loosened and separated from the woody stalk. The bundles
are steeped in water at least 60 cm to 100 cm depth. The retting process is
completed in 8 to 30 days, when the barks separateout easily from the stick or
wood and the fibres are ready for extraction. A development in recent years is
adoption of ribbon retting technology in jute growing trade of the country.
Stripping (Fibre Extraction)
7. Stripping is the process of removing the fibres from the stalk after the
completion of retting. Fibres are removed from the stalk by any one of the
following methods:
Single plants are taken and their fibers are taken off.
Taken off a handfulof stalks, breaking it in a to and fro motion in water.
Washing the stalks firstby standing in waistdeep water and then
stripping afterwards.
When there is a plenty of water, bundles of stalks are laid in the pond ditches
or slow moving streams and left for 5-15 days under water. The bunch of stem
is held in one hand and the rootend tapped lightly with a mallet. After loosens
the restof fibres, fibres are extracted and washed.
Washing and Drying
Extracted fibres arewashed in clean water. The dark colour of fibres can be
removed by dipping them in tamarind water for 15 to 20 minutes and again
washed in clean water. After squeezing excess water the fibres are hang on
bamboo railing for sun drying for 2-3 days.
Bailing and Packing
The jute fibre is graded into tops, middles, B, C and X-bottoms. Packing into
Kutcha bales about250 pounds for use in the home trade. they are
transported to jute market or direct to jute mills.
8. Jute Gradation
GRADING: Thereare two stages of grading, one for the home trade and
another
lefinitionof Grading: For the purposeof jute processing in jute manufacturing
or to export after assorting juteare classified on the basis of differentqualities
before pucca and kutcha baling. This classification is known as jute grading.
Two types of grading: for the export trade. Grading factors for jute are
length, firmness of fibre, lustre, strength, clearness, freedom from defects, and
the amounts of rootend which will have to be cut off. The preliminary grading
is done by kutcha balers.
• Puccagrading
Kutcha grading
Godown price: the price of jute including jute price, transportcostand
godown chargeis known as godown price.
Issue price: the adjusting averageprice of godown price, cutting and HJR jute is
known as issueprice.
Batchprice: the averageissueprice of different grade of jute for a specific
batch is known as batch price.
Chemical CompositionOf Jute fiber
Chemically jute fiber contains
a-cellulose....... (58-63 %)
lignin........ (12-14%)
Hemicelluloses....... (22-24%)
9. waxes....... (0.4-0.8%)
pectin....... (0.2 -0.5 %)
protein ....... (0.8-1.5 %)
mineral matters....... (0.6-1.2 %)
And traces of tannin and coloring matters.
The hemicellulose portion is a mixture of pentosan (xylan: 12-4%), polyuronide
(4-5 %) and contains acetyl groups (3.2-3.5%) etc.
Cellulose
Figure:Cellulose
Figure:Hemicellulose
11. Figure:Jute Fiber Internal Structure
Chemical Properties of Jute Fiber:
Effect of Acids: Easily damaged by hot dilute Acids and conc. cold Acid.
Effect of Alkalis: Fibers aredamaged by strong alkali. Fiber losses weight when
it heated with caustic soda.
12. Effect of Bleaches: Resistantto bleaching agents(Bleaching agent, H2O2,
NaOCl, NaClO2, Na2O2, CH3COOH,KMnO4etc.)
Effect of Light: Color changes slightly in presenceofsun light. Ithappens due
to presence of lignin in fiber.
Effect of Mildew: Prevention ability is better than Cotton and Linen. Dyeing
ability: Easy to dyeing. Basic dye is used to color jute fiber.
Manufacturing Process Flow Chart of Raw Jute Spinning
Selection of jute for a batch
Piecing up
Softening and Lubricating
Conditioning or Pilling
Breaker Carding
Finisher Carding
First Drawing
Second Drawing
13. Third Drawing
Spinning
Jute Pretreatment
Singeing is an important part of pretreatment. This is the burning off of
protruding fiber ends from the surface of the fabric. If not done properly,
unclear print patterns, mottled fabric surfaces, and pilling results.
• Looseyarns not firmly bound into the fabric structure;
• Protruding fibreends sticking out of the textile yarns and/or fabrics.
Singeing Process:
Singeing process is as follows:
• To producea smooth surfacefinish on fabrics made from staple fibers
firstthe fabric surfaces arebrushed lightly to raise the unwanted fiber
ends.
• Then the fabric is singed with or passed over open gas flames. The fiber
ends burn off.
Desizing of Jute fabric:
Desizing is the process of removing the sizematerial from the warp
yarns in woven fabrics. Sizing agents are selected on the basis of type of
fabric, environmental friendliness, easeof removal, cost considerations,
effluent treatment, etc.
14. Desizing Process:
The major desizing processes are:
• Enzymatic desizing of starches on cotton fabrics
• Oxidative desizing
• Acid desizing
• Removal of water soluble sizes
Enzymetic Desizing
Enzymatic desizing is the classical desizing process of degrading starch
size on cotton fabrics using enzymes. Enzymes are complex organic,
soluble bio-catalysts, formed by living organisms that catalyze chemical
reaction in biological processes. Enzymes are quite specific in their
action on a particular substance. A small quantity of enzyme is able to
decompose a large quantity of the substance it acts upon. Enzymes are
usually named by the kind of substance degraded in the
reaction it catalyzes. Amylases is the enzyme that hydrolyses and
reduces the molecular weight of amylase and amylopectin molecules in
starch, rendering it water that is soluble enough to be washed off by the
fabric. Effective enzymatic desizing requires strict control of pH,
temperature, water hardness, electrolyte addition and choice of
surfactant.
Advantages of Enzymatic Desizing
• No damage to the fibre
• No usageof aggressivechemicals
• Wide variety of application processes, and
• High biodegradability
Disadvantages Enzymatic Desizing
15. Lower additional cleaning effect towards other impurities, no effect on
certain starches (e.g. tapioca starch) and possibleloss of effectiveness
through enzymepoisons.
Scouring And Bleaching:
Scouring:
Natural fibers contain oils, fats, waxes, minerals, leafy matter and motes as
impurities that interfere with dyeing and finishing. Synthetic fibers contain
producer spin finishes, coning oils and/or knitting oils. Mill greaseused to
lubricate processing equipment mill dirt, temporary fabric markings and the
like may contaminate fabrics as they are being produced. The process of
removing these impurities is called Scouring. Even though these impurities are
not soluble in water, they can be removed by Extraction, dissolving the
impurities in organic solvents, Emulsification, forming stable suspensions of
the impurities in water and Saponification, Converting the contaminates into
water solublecomponents.
Bleaching of Jute:
Although jute fibres contain considerableamount of impurities, jute materials
are generally bleached without prior scouring due to its alkali sensitivity. Jute
differs fromlinen in its high lignin content (about11-12% dry weight). The
lignin, together with hemicelluloses, provides inter-cellular binding material
known as lamella, holding the fibre together. In contrastto linen, it is neither
desirable nor necessary to delignify jute. Jute is effectively bleached by
hydrogen peroxide while most of the lignin remains.
A consequenceof the presenceof lignin in bleached jute is that its whiteness is
not fast to light.
Estimation Process of Jute Pretreatment
weight loos is rhe ratio of loose weight to the weight of untreated fabric shown
in percentage.first untreated fabric is taken and its weight is measured by
electric balance. And after treating with a sulfuric acid and making fabric acid
16. free the fabric is completely dryed then the fabric is weighted again and the
difference of weight is measured.
Weight loss = (untreated fabric wt.- treated fabric wt.)/ (untreated fabric wt.)
*100
Untreated fabric sample wt.=122g
Treated fabric(dry) wt.= 115.6g
Weight loss = (untreated fabric wt.- treated fabric wt.)/ (untreated fabric wt.)
*100
= (122-115.6)/(122)*100
=5.25%
Water absorptiontesting
The maximum percentage of water absorption for the manufactured hybrid
composites was investigated under ASTM D 570 standard. Thesamples were
completely submerged in the distilled water and were taken out from the
water after 24 h of immersion. Then the samples were weighted after all the
water of the surfacewas removed with a clean dry cloth. This procedurewas
regularly repeated at an exposureof 24, 48, 98, 196, and up to 312 h. The
water-absorption percentageis calculated using the following Eq.
Waterabsorption(%)=m2-m1m1×100
Where m1 is the weight beforesubmerging in water in gram, and m2 is the
weight after submerging in water in gram.
Busting strength test:
Bursting Strength
Tensile strength tests are generally used for woven fabrics wherethere are
definite warp and weftdirections in which the strength can be measured.
However, certain fabrics such as tted materials, lace or non-wovens do not
have such distinct directions where the strength is at a maximum. Bursting
strength is an alternative method of measuring strength in which the material
is stressed in all directions at the sametime and is therefore moresuitable for
such materials. There are also fabrics which are simultaneously stressed in all
directions during service, such as parachute fabrics, filters, sacks and nets,
17. whereit may be important to stress them in a realistic manner. A fabric is
more likely to fail by bursting in service than it is to break by a straighttensile
fractureas this is the type of stress thatis present at the elbows and knees of
clothing.
When a fabric fails during a bursting strength test it does so across the
direction which has the lowest breaking extension. This is becausewhen
stressed in this way all the directions in the fabric undergo the same extension
so that the fabric direction with the lowestextension at break is theone that
will fail first. This is not necessarily the direction with the lowest strength.
Diaphragm of Bursting Test
The British Standard describes a test in which the fabric to be tested is
clamped over a rubber diaphragm by means of an annular clamping ring and
an increasing fluid pressureis applied to the undersideof the diaphragm until
the specimen bursts. The operating fluid may be a liquid or gas.
Two sizes of specimen are in use, the area of the specimen under stress being
either 30mmdiameter or 113mm in diameter. The specimens with the larger
diameter fail at lower pressures (approximately one-fifth of the 30mm
diameter sale). However, there is no direct comparison of the results obtained
fromthe different sizes. The standard requires ten specimens to be tested.
18. Fig : bursting strength test
In the test the fabric sampleis clamped over the rubber diaphragm and the
pressurein the fluid increased at such a rate that the specimen bursts within
20 ± 3 s. The extension of the diaphragm is recorded and another test is carried
out without a specimen present. The pressureto do this is noted and then
deducted fromthe earlier reading.
The following measurements are reported:
• Mean bursting strength kN/m2
• Mean bursting distension mm
• Liquid Piston
• Rubber
• Diaphragm
• Specimen
• Clamp
The US Standard is similar using an aperture of 1.22 ± 0.3 in (31 ± 0.75mm) the
design of equipment being such that the pressureto inflate the diaphragm
alone is obtained by removing the specimen after bursting. The test requires
ten samples if variability of the bursting strength is not known.
19. The disadvantageof the diaphragm type bursting test is the limit to the
extension can be given to the sample owing to the fact that the rubber
diaphragm has to retch to the sameamount. Knitted fabrics, for which the
method is intended, en havea very high extension.
Result:
Sample Brusting strength
Untreated fabric 19 kg
Treated fabric 15 kg
20. Introduction To Cotton:
Today cotton is the mostused textile fibre in the world. The word cotton
comes from Arabic word "katan".It is called the king of fibres. Cotton is the
backboneof worlds textile market. Cotton and cotton related textile industries
are central to the economic growth of both developing and least developing
countries contribute to sustainableand exclusive economic development.
Cotton is a cellulosic Vegetable fiber. The scientific name of cotton is
Gossypium barbadense(Egyptian cotton). This natural cotton fibers comes
froma substancesurrounding cotton plant seeds. Cotton fiber is the first used
fiber all around the world. The chemical structureis constituted by 94% of pure
cellulose. Its cross section is bean shaped Glucoseis to be regarded, therefore,
as the smallest component of the cellulose
Cellulose is an organic compound with the formula (C,H₁00s). It willbe
appreciated that naturalcellulose is built up of glucoseresidues in this way:
21. Where, a is the degree of polymerization (DP). The DP of cotton polymer is
about 5000. Onecellulose polymer may contain 10,000 glucoseunits.
Fiber Morphology
Fiber Morphology is the study of the internal structureof fibers i.e.
identification, analysis and description of the internal structureof fibers.
The macro-structure of Cotton:
The cotton fiber is a single plant cell. Its cross-section is oval, compared with
the normalhexagonal plant cell. Cotton has a distinct cuticle, well developed
primary and secondary walls and a lumen. The fibre length to breadth ratio of
cotton range fromabout 6000:1 for thelongest and best types to about 350:1
for the shortestand coarsestcotton types. The greater this ratio the more
readily can the cotton fibre be spun into yarn.
Composition of Cotton:
22. The chemical composition of cotton fibers and the quantity of different
constituents vary greatly with the type of plant, soil and climate. Raw cotton
fiber, after ginning, is essentially composed 94% cellulose.
Chemical composition of cotton fiber:
Constituents Percent
Cellulose 94.4
Protein 1.3
Pectic substances 1.2
Ash 1.2
Fat and wax 0.6
Organic acid, sugar and others 1.7
Classification of the cotton fibres:
Classification of cotton on the basis of region:
23. A) Sea Islandcotton:This is the highest quality and most variable of all
commercial cottons.
• Length- Theaveragelength of this fibreis about 2 inch mm).
• Diameter is 0.017mm.
Specific gravity 1.5gm/cm3.
• Very good Lusters,Uniformity, Maturity, Twist& softness.
B) Egyptian cotton:There are two kinds of Egyptian cotton, one brown
and other white, like as sea islandcotton.
• Avg. length is 1.5-1.75 inch (38-44mm).
• Very good uniformity.
• . Itcontains few immature and dead fibres.
• Diameter is 1/1500 inch (0.017). •Specific gravity 1.5gm/cm3.
C) South Americancotton:
• Staple length is 1-1.5 inch (25-38mm).
• Diameter of 1/1300 inch and is very suitable for using with other
regenerated fibre.
D) Americanupland cotton:
This variety is fromgossipium hirsutum are generally know as upland cotton.
The most American cotton belongs to this groups. The staple length of
American pima cotton is from9/8 to 3/2 inch and the fibre is fine, strong,
lustures, silky and creamy brown whitein color.
E) Indian cotton:
Ithas shortfibre, length is 0.6-0.8inch. Itis only suitable for producing coarse
yarn.
F) China cotton:
24. This is the lowest gradecommercial cotton. Length is 0.5-0.7 inch. Twistis not
highly developed and rather harsh.
Classificationof cotton on the basis of length:
According tolengthcottonis classifiedas following:
Short staple: 3/8 inch to 15/16 inch (10mm-24mm) in length.
Mediumstaple: 1 inch to 1-1/8 inch (25mm-28.6mm) in length.
Long staple: 1-3/16 inch to 2-1/2 inch (30mm-63.5mm)in length.
Polymeric structure of cotton:
Cotton is a cellulosic substance, very long linear polymer. Itis a polymeric
sugar of polysaccharidemade up of many repeating cellobiose unit, which
consists of two glucoseunits connected to each other by 8-ether linkages. The
cotton polymer consists of about 5000 cellobiose units (DP-5000),about
5000nm in chain length and 0,8nm thick. The chemical group are -OH and-
CH2OH act as side groups, and -O- linking element The polarity gives H-
bonding between -OH groups and van der waals forces and intract strong
intermolecular forces between chains, coupled with the high linearity of the
cellulose molecule account for the crystallinenature of cellulosic fibres.
Fig: Cellulose Monomer Fig: Cellobiose Unit
25. The existence of cellulose as the common material of plant cell walls was first
recognized by AnselmPayem in 1838. Celluloseis a long chain polymer, made
up of repeating units of cellubiose.
Physical Properties of Cotton:
1. Thickness: Micronairevalue from 3 to 6
2. Color: White
3: Length: Shortfibre
4. Density: 1.5g/cc
5. Tenacity: Medium to good, 26 to 43 cN/Tex
6. Moisture regain: 8.5% (at65% moistureat 20 degree C)
7. Elongation: 3.5 to 7.5%
8. Flame reaction: Rapidly flammable
Chemical Properties of Cotton:
Cotton is a natural cellulosic fiber and it has some chemical properties.
Chemical properties of the cotton fiber are given below:
1. Effect of Acids: Cotton is attacked by hot dilute acids or cold concentrated
acids which it disintegrates. Itis not affected by acids.
2. Effects of Alkalis: Cotton has an excellent resistance to alkalis. It swells in
caustic alkalis (NaOH) but it does not damaged. Itcan be washed repeatedly in
soap solution without any problem.
3. Effect of Organic Solvent: Cotton has high resistanceto normalcleaning
solvents. Cotton is dissolved by the copper complexes, such as cuprammonium
hydroxide, cupriethylenediamine and concentrated 70% H2SO4.
4. Effects of Insects: Cotton is not attacked by moth-grubs or beetles.
26. 5. Effect of Micro Organism: Cotton is attacked by fungiand bacteria. Mildews
will feed on cotton fabric, rotting and weakling the materials. Mildews and
bacteria will flourish on cotton under hot and humid condition. They can be
protected by impregnation with certain types of chemicals. Copper
Nepthenate is one of the chemical.
Process flow chart of cotton processing:
27. used in making underwear knits, but figures vary according to the type of
machine used and the fabrics produced
Pretreatment of cotton:
Pretreatment of cotton includes a series of operations that preparethe textile
productfor subsequentfinishing treatments such as dyeing, printing and
finishing. The pretreatment stage of cotton includes for example singing,
desizing, scouring, bleaching. Each process varies according to the processing
condition and the above-mentioned specific situations. Some of this process
are described below:
Singeing:
Singeing is a process of burning protruding fibers from
a textile structure:
28. • The verb 'singe literally means 'to burn superficially". Technically,
singeing refers to the burning-off of:
• Loosefibres not firmly bound into the yarn and/or fabric structure;
• Looseyarns not firmly bound into the fabric structure;
• Protruding fibreends sticking out of the textile yarns and/or fabrics.
Singeing Objectives & advantages:
• Singeing of a fabric is done in order to obtain a clean fabric surface
which allows the structureof the fabric to be clearly seen.
• Fabrics, which havebeen singed, soil less easily than un-singed. fabrics.
• The risk of pilling, especially with synthetics and their blends, is
reduced incase of singed fabrics.
• Singed fabrics allow printing of fine intricate patterns with high
• clarity and quality.
• The risk of faulty dyeing with singed articles dyed in dark
shades is considerably reduced, as randomly protruding fibres
are removed in singeing which could cause diffused reflection
of light.
Desizing: Desizing is the process of removalof size materials (starch, gum etc)
fromthe warp yarn of woven fabric. Desizing is the firsttreatment of wet
process in textile.
Objects of desizing
1. To remove sizing materials from the warp yarn of woven fabric.
2. To absorbency of the fabric.
3. To reduce stiffness,
4. To make softand pliable.
29. 5. To make the fabric ready for the next process like scouring, bleaching,
dyeing and printing.
Desizing Reaction:
Scouring:
Scouring is the process whereall naturaland added impurities such as oil,
wax, fat etc are removed to make the fabric hydrophilic and clean the
textile materials.
Object of scouring
1. To removenatural and added impurities such as oils, wax, fat etc.
2. To increasewater absorbency of fabric or yarn without undergoing
physicaland chemical damage.
30. 3. To produceclean material.
4. To makethe fabric ready for uniform dyeing, printing.
Chemicals used in scouring and their function:
1. Alkali.
2. Wetting agent.
3. Detergent.
4. Sequestering agent.
5. leveling agent.
1. Alkali:
The function of alkali is to remove the naturalimpurities such as oil, fat,
wax etc fromthe fabric or yarn.
2. Wetting agent:The wetting or surfaceactive agent reduces the surface
tension between the caustic water solution and fabric so that the oil,
waxes and caustic soda are in intimate contact with each other.
3. Detergent:
The detergent is also a surfaceactive agent which is used for cleaning the
surfaceof fabric or yarn.
Bleaching:
Bleaching is the process for improving the whiteness of textile materials by
removing the naturalcolouring matters. Bleaching produces a pure,
permanent and basic white effect on fabric which is suitable for level
31. dyeing, and sharp printing. During bleaching it should be carefully observed
that the bleaching agent does not reduce the tensile strength of fabric.
Objects of bleaching
1. Destruction of natural coloring matters from the fabric.
2. To impart a pure, permanent and basic white effect to the fabric.
3. To obtain permanent white color of the fabric.
4. To increaseabsorbency of textile material for dyeing, printing and other
operation.
Bleaching action of hydrogenper oxide on cellulose:
Under certain condition particularly with regard to pH hydrogen per oxide
will liberate hydrogen and per hydroxylions in the following manner.
H,O, H + HO,
Alkalinity favours thelibereation of per hydroxylions becausethe positively
charged hydrogen ion is neutralized but excessivealkalinity causes the
peroxide to become unstable. The perhydroxylion is responsiblefor
bleaching action.
The above reaction takes place in presence of catalyst. The liberated.
oxygen however has no bleaching action and hydrogen per oxide is wasted.
32. Therefore the presence of catalysts are the causeof loss of bleaching
powder i.e. hydrogen per oxide.
Estimation Process of cotton Pre-treatment :
Introduction To Reactive Dye:
A dye, which is capable of reacting chemically with a substrateto form a
covalent dye substratelinkage, is known as reactive dye. Here the dye
contains a reactive group and this reactive group makes covalent bond with
33. the fiber polymer and act as an integral partof fiber. This covalent bond is
formed between the dye molecules and the terminal -OH (hydroxyl) group
of cellulosic fibres on between the dye molecules and the terminal -NH2
(amino) group of polyamide or woolfibers.
Properties of Reactive Dye:
1) Reactive dyes are anionic dyes, which are used for dyeing cellulose,
protein and polyamide fibres.
2) Reactive dyes are found in power, liquid and print pasteform.
3) During dyeing the reactive group of this dye forms covalent bond with
fibre polymer and becomes an integral parts of the fibre.
4) Reactive dyes are soluble in water.
5) They have very good light fastness with rating about 6. The dyes have
very stable electron arrangement and can protect the degrading effect of
ultra-violet ray.
General structure of reactive dyes:
The general structureof reactive dye is:D-B-G-X.
Fig: Chemical structureof reactive dyes
34. Here,
D= dye part or chromogen (color producing part)
Dyes may be direct, acid, disperse, premetallised dye etc.
B = bridging part.
Bridging partmay be-NH- group or -NR- group. G=reactive group bearing
part.
X= reactive group.
Classificationof reactive dye:
1. On the basis of reactive group a) Halogen (commonly chlorine)
derivatives of nitrogen containing heterocycle, like 3 types
Triazine group
Pyridimine group
Quinoxaline dyes
Example:
Triazine derivatives: Procion, Cibacron.
Pyridimine derivatives: Reactone
Quinoxaline derivatives: Levafix.
b) Activated vinyl compound
Vinyl sulphone
Vinyl acrylamide
Vinyl sulphonamide.
35. Example:
Vinyl sulphone: Remazol
Vinyl acrylamide: Primazine
Vinyl sulphonamide: Levafix.
2. On the basis of reactivity
a) Lower reactive dye: Reactivity of these dyes is low. So highly alkaline
environmentis required for the fixation of these dyes with substrate. Here
pH is maintained 12-12,5 by using NaOH in bath.
Example: Cibacon T, Drimarene.
b) Medium reactive dye:
These are medium reactive dyes. Here pH is maintained 11-12 by using
Na2CO3 in dye bath.
Example: Levafix E, Remazol.
c) Higher reactive dye:
These dyes are medium reactive.So fixation of these dyes is easy and lower
alkaline medium is kept. Here pH is maintained 10-11 by using NaHCO3 in
dye bath.
Example: Procion Mx, DrimareneKLP.
3. On the basis of dyeing temperature
a) Cold brand:
These types of dyes contain reactive group of high reactivity. So dyeing can
be done in lower temperature i.e. 32°-60°C. For example: Procion M, Livafix
E.
b) Mediumbrand:
36. This type of dyes contains reactive groups of moderate reactivity. So dyeing
is done in higher temperature than that of cold brand dyes i.e. in between
60°-71°C temperatures.
For example: Remazol, Livafix are medium brand dyes.
c) Hot brand:
This type of dyecontains reactive groups of least reactivity. So high
temperature is required for dyeing i.e. 72°-90°C temperature is required for
dyeing.
For example: Procion H, Cibacon are hot brand dyes.
Trade Names of Reactive Dye:
Trade name Manufacturer Country
Procion I.C.I U.K
Ciba cron Ciba Switzerland
Remazol Hoechst Germany
Levafix Bayer Germany
Reactone Geigy Switzerland
Primazin BASF Germany
Drimarine Sandoz Switzerland
37. Hydrolysis of Reactive Dye:
Under alkaline reactive dye reacts with the terminal hydroxylgroup of
cellulose. But if the solution of the dyekept for long time its concentration
drops. Then the dye react with the hydroxyl(OH) group of water.
This reaction of dyewith water is known as hydrolysis of reactivedye. After
hydrolysis dyecon not react with fiber. So hydrolysis increases theloss of dyes
Hydrolysis of halogen containing reactive dye:
D-R-CI+H-OH-------------DR-OH +HCI
Hydrolysis of activated vinyl compound containing group:
D-F-CH2-CH2-OSO3H +H-OH------- D-F-CH2-CH2- OH+H2SO4
For preventing hydrolysisthe following precautionsare taken
1. As hydrolysis increases with increasing temperatureduring dissolving and
application temperature should not be more than 40°C.
2. Dye and alkali solution are prepared separately and mixed justbefore
using.
4. Dyeand alkali should not be kept for long time after mixing.
Advantages of Reactive Dye:
Simplifies dyeing process
38. Improvefastness
Disadvantages of Reactive Dve:
Hydrolysis accompanies fixation
Waste of dy
Extra wash step
Colored effluent dischargeprocessing
Large amountof electrolytes used
Basic conditions create anionic repulsion of dyeand fiber
METHOD AND MATERIAL :
39. Name & Functionsof the Apparatus
Standard Recipe of Cotton Dyeing withReactive Dye
Name Recipe Function
40. colldBrand ReactiveDye (Red 0.01% owf
0.5% owf
1% owf
1.5% owf
2% owf
3% owf
Its applicationtofibers involves
Exhaustion,Migrationand
Fixationof dye all overthe fiber
to occur dyeing
CommonSalt/Electrolyte
(NaCl
30 gm/Lite The additionof salts/electrolytes
assiststhe Diffusionand
Exhaustionof anionicdye
moleculesbyneutralizingthe
negative surface charge of
cellulosicfiberswhichexhibited
by the fiberdue tocarrying
reactive groupsas,(-OH, -COOH).
Soda-ash(Na2CO3) 10 gm/Lite The additionof Alkali forms
Reactive Cellulosate ionbythe
reactionbetweenthe Terminal
group(Cell-OH) and-OHions
providedbythe Alkali
WettingAgen 1 cc/Liter Reducessurface tension,
interfacial tensionof water,
providesbetterwettingof fabric.
SequesteringAgent 1 cc/Liter Formsstable & soluble
complexeswithmetal ions
presentinwaterandreduces
waterhardness.
Temperature 40°C It facilitatesthe dye moleculesto
be properlydiffusedintothe
interiorof the chemical structure
of fiber
p H 10-11 It facilitatesthe affixationof
chemical bondingduringdyeing.
Time 30 minutes
Material : Liquor 1:50
Standard Recipe of Jute Dyeing withReactive Dye
41. Name Recipe Function
colldBrand ReactiveDye (Red 0.01% owf
0.5% owf
1% owf
1.5% owf
2% owf
3% owf
Its applicationtofibers
involvesExhaustion,
MigrationandFixationof dye
all overthe fiberto occur
dyeing
CommonSalt/Electrolyte
(NaCl
30 gm/Lite The additionof
salts/electrolytesassiststhe
DiffusionandExhaustionof
anionicdye moleculesby
neutralizingthe negative
surface charge of cellulosic
fiberswhichexhibitedbythe
fiberdue tocarrying reactive
groupsas,(-OH, -COOH).
Soda-ash(Na2CO3) 10 gm/Lite The additionof Alkali forms
Reactive Cellulosate ionbythe
reactionbetweenthe Terminal
group(Cell-OH) and-OHions
providedbythe Alkali
WettingAgen 1 cc/Liter Reduces surface tension,
interfacial tensionof water,
providesbetterwettingof
fabric.
SequesteringAgent 1 cc/Liter Formsstable & soluble
complexeswithmetal ions
presentinwaterandreduces
waterhardness.
Temperature 40°C It facilitatesthe dye molecules
to be properlydiffusedintothe
interiorof the chemical
structure of fiber
p H 10-11 It facilitatesthe affixationof
chemical bonding
duringdyeing.
Time 30 Minutes
Material : Liquor 1:50