Dyeing of textilesDyeing of textiles in wet processing refers to subjecting the substrate (cotton fabric/yarn) to a chemical treatment that renders uniform shades /colors. Each and every fiber has to be treated in different ways with different type of dyestuff and depensing on the nature of substrate and its physical form (fiber, yarn or fabric), specific equipment or machinery would be used. Here we will consider including as many type of fibers as possible, so that the reader will be benefitted in full.

Cotton Dyeing

 

 

Cotton Dyeing: Cotton can be dyed with the following dyestuffs., viz., Direct, Reactive, Vat, Suplur, Pigment and Solubilized vat dyes. Cotton is anionic in nature and can be dyed easily with cationic chromophores.

Batch Dyeing: When small quantities of up to 300 to 500 meters or 100 to 500 kgs of yarn or fiber to be dyed, then batch dyeing machines would be used for dyeing. Cotton batch dyeing machines are viz., open beck dyeing machine, spray dyeing machine (for hank yarn dyeing), cabinet dyeing machine (for hank dyeing), jigger and winch dyeing machines for small fabric batches, enclosed yarn and fiber dyeing machines and jet dyeing machines.

Semi Continuous and Continuous dyeing: When medium size batches of fabric length 1000 to 2000 meters are to be dyed, then Cold Pad Batch method is most suitable with reactive dyes.With vat dyes pad, dry, jig develop is suitable. When long batch lengths of more than 3000

meters of a same shade to be dyed then continuous dyeing - pad - dry- chemical-pad - dry - steam or thermosol dyeing is the most suitable methods.

Direct dyes: The name direct dye explains that this dye application is simple and direct. The dyestuff should be dissolved in water and the well prepared RFD (Ready For Dyeing) fabric or yarn is entered in to the dye solution and worked for 30 to 45 minutes at boil. Afterwards,the dyed material would be given a short cold wash and fixed with some cationic dye fixing agent.

Reactive dyes: The first synthetic organic dyes were called substantive dyes or direct dyes. These dyestuffs do not have attraction towards cotton fiber. However due to high temperature (90 to 100°C) it has been forced to enter the cellulose molecules. Using a strong cationic fixing agent these dyes used to get fixed on the fiber. But the final fastness towards washing and rubbing of these dyestuffs were very poor. In order to solve this poor wash fastness qualities, a dyestuff that would react with cellulose and become part and parcel of it was developed; since these dyes react with cellulose and form a strong covalent bond, these are called reactive dyes.Classes of reactive dyes: Reactive dyes are classified according to their chemical names and their reactivity or presence of number of reactive groups. The general classifications are as below:

Vat Dyes: Vat dyes do not dissolve in water, while when reduced to be leuco salt by reducing agent under alkaline conditions, they can dissolve in water and get feature of immediacy with

cellulose fibers, which is the way to achieve the purpose of dyeing. Then stable shade and good color fastness would come out via oxidation and soaping.

Reduction of dyes: Insoluble reducing dye will change into soluble leuco.

.Different levels of the best staining methods are brought out according to the reduction dyes' reduction potential and level of its immediacy to fibers.

Dye-uptake of leuco: The leuco is adsorbed by fiber and then it is diffusing into the fiber.

It is necessary to use soft water or softened water in dyeing process. Hereby it is suggested to add the water softener for 1g/L to some poor quality cotton fabric. The water softener would not only absorb calcium, magnesium ions, but also the iron, copper ions which are absorbed by the pipe into the dye bath, and finally keep the solubility of leuco.

The sodium sulfate could increase the dyeing absorption rate, and surely it is also a good promoter. So it can be added into the dye bathes with medium or low immediacy according to the demand.

Batch dyeing characteristics:  No single classification of vat dyes by dyeing characteristics has been as useful  or as generally accepted as has the classification of direct dyes in to groups A, B and C.

One method of classification of vat dyes in to four principle sub-groups: IK, IW, IN and IN Special, which still leaves a few dyes out, such as C.I. Vat Black 9. This classification is based on the different substantivities of the leuco vat anions and the corresponding differences in dyeing temperatures and the salt, caustic soda and hydro concentrations necessary to give the best over all dyeing results. The importance of these traditional groupings is restricted to batch dyeing with a leuco vat anions. substantivities of the leuco vat anions and the corresponding differences in dyeing temperatures and the salt, caustic soda and hydro concentrations necessary to give the best over all dyeing results. The importance of these traditional groupings is restricted to batch dyeing with a leuco vat anions.

The 'I' stands for 'Indanthrene' . "K" stand for the German word, Kalt, meaning cold. Dyes (reduced leuco vat anions) in this group are dyed at room temperature with a relative high salt concentration ( common salt or anhydrous sodium sulphate) and relatively low sodium hydroxide (caustic soda) concentration, all of which tend to promote higher substantivity and exhaustion of equilibrium.Indanthrene' . "K" stand for the German word, Kalt, meaning cold. Dyes (reduced leuco vat anions) in this group are dyed at room temperature with a relative high salt concentration ( common salt or anhydrous sodium sulphate) and relatively low sodium hydroxide (caustic soda) concentration, all of which tend to promote higher substantivity and exhaustion of equilibrium.

"W" stands  for German/English word warm. Dyes in this group are more substantive and can be dyed at 40 to 50 C (100 to 120 F) with less salt and slightly more alkali.

"N" stands for the German/English word normal. Such dyes are even more substantive, require more alkali but no salt, and can be dyed at 60 C (140 F). The IN special dyes require even more alkali.

Viscose Dyeing

Viscose yarn/fabric Dyeing: Viscose is a regenrated cellulose fiber and can be dyed with the following dyestuffs., viz., Direct, Reactive, Vat, Suplur, Pigment and Solubilized vat dyes.

Physical Properties of Viscose: Before we go in to the details of wet processing of viscose, its better to know the basic physical and chemical properties of this fiber, so that one can understand how careful he should handle this material.

1. Viscose has lower tenacity in both wet and conditioned state than cotton – more care is necessary to prevent fabric breakages and tears in wet processing

2. Viscose has greater elongation in both wet and conditioned state than cotton – it will be stretched or distorted more under tension.

3. Viscose and Modal fibres are supplied in a pure state and with a higher degree of whiteness than cotton. Bleaching is only required for a full white or pastel shades. Viscose/cotton blends require bleaching baths with a reduced chemical content.

4. The water retention value (swelling index) of viscose is very much higher than that of cotton.In aqueous liquors, viscose fibres tend to swell more strongly than Modal fibres or cotton. This swelling process happens very quickly and is almost complete after ten seconds at the lower temperature range.Fabrics become much more stiff when wet because the fibres are so swollen.In their swollen state, viscose fibres can become set to a certain extent. This is called hydroplasticity.

5. Viscose has higher dye affinity than cotton.6. Inferior diffusion and penetration. More kinetic energy needed. Hot reactive dyes.7. Viscose loses tenacity when wet.More care needed to avoid damage.

8. Wet swelling increases with temperature. Very important in package dyeing. Liquor circulation should mainly be IN to OUT. OUT to IN should be < 30 seconds.

9. Swelling of fibres makes wet fabrics stiff. Swelling and heat can set creases. Use longer L.R. than for cotton. Keep liquors above 50° C, Cool at maximum 1° C per min. Use suitable anti-crease lubricants.

10. Viscose may contain residues of sulphur. Mild peroxide bleach may be necessary to remove sulphur.

11. Dyes have higher substantivity and faster fixation. Use ‘Migration’ dyeing techniques (at up to110° C). Add salt after dye.

Refer viscose pretreatment for details.

Acrylic Fiber properties

 

Basic physical and chemical properties of Acrylic Fiber:It is important to know a little about the basic physical and chemical properties of acrylicsubstrates and how these influence the choice of processing techniques. The following pointsshould be noted.(1) Acrylic substrates can sequester iron and copper ions and once these are absorbed they arevery difficult to remove. Residual metal ions can cause fabric yellowing and dull opticalwhites and bright pale shades; light-fastness may also be impaired.(2) The use of strong alkali above the Tg of the fibre can lead to some problems with residualalkali. Once alkali is absorbed, it is difficult to remove and may still be present when thematerial is dried at elevated temperatures. These conditions will not be encountered in thedyeing of 100% acrylic substrates but may well be in the dyeing of cellulosic blends.(3) One of the attributes of acrylic substrates is that they can produce high bulk, and henceaesthetically pleasing, yarns, garments and fabrics. In order to maximise these properties it isimportant to be aware of the need to control tension and temperature.

(4) Processing tensions should be kept as low as possible during wet and finishing processes.(5) The use of free chlorine-containing bleaches should be avoided at temperatures at or closeto the Tg of the fibre. Hypochlorite bleaching above the fibre Tg may well initially producea whiter substrate but almost invariably the fibre will yellow on subsequent drying at anelevated temperature or on exposure to light. It is virtually impossible to remove residualchlorine completely even after the most thorough antichlor treatments once acrylicsubstrates have been exposed above their Tg.

PHYSICAL AND CHEMICAL PROPERTIES IN RELATION TO DYEINGThe most important practical properties of an acrylic or modacrylic fibre to a dyer are the:(1) base colour of the fibre and how stable this is to the dyeing process;(2) rate at which the fibre will dye and the number of acidic end groups in the polymer chain;(3) hot wet mechanical properties;(4) resulting fastness properties of the dyed material.

Polyester Dyeing

Polyester Dyeing:

Exhaust dyeingDyeing 100% polyesterWhen dyeing with disperse dyes the levelness of the dyeing is determined by thedispersion stability, rate of dyeing and migration. An increase in migration demandslonger dyeing times. The rate of dyeing and therefore the heating rate must be controlledin such a way that the dyeing is level from the beginning by means of controlledadsorption.Pretreatment of the goodsThe material usually contains small amounts of water-soluble or emulsifiable preparationswhich can be readily washed off. With tops, loose fibres and smooth or textured yarnsrinsing for IO min with cold water is often sufficient. Depending on the degree of contamination of the substrate one-bath scouring and dyeing of grey, unset piece goods of textured yarns is possible.

At the start of the dyeing process rinse the grey goods for 5 min at 20-30°C, then drainand add 1-2 ml/l Sandopan LFW Liquid to the fresh bath. On reaching 60°C add the otherchemicals and continue dyeing according to the programme shown below:

Dyeing under HT conditions (130°C)

Form of the goods- loose fibres and tops- yarn- piece goods (jet, overflow and beam dyeing machine)

Dye selection : Foron RD or S, SE and E dyes depending on the fastness require-mentsfor the subsequent operations or for the final article.

Funtion AdditionProduct and amount

pH control essential

dispersantadvisable; Exception: sometimeswith very deep shades (black)

Levelling agentif required (substrate/form,machine, shade)

Carrier or dyeing accelerantif required (Substrate/form,machine, shade)

Anticreasing agentsrecommended on jet and overflowmachines

Remarks on dyebath additions- Dyeing on partially flooded HT dyeing machinesFoam formation during dyeing in these machines causes considerable problems so low foaming chemicals must be used.

Standard HT dyeing programme for 100% PES- set dyebath at 60°C- add dyebath additions and run for 10 min- add dye and run for 10 min- heat to 130°C at 1.5°C/min- fix for x min at the dyeing temperature as shown in table below- cool, drain, rinse, aftertreat.

Fixation times under HT conditions

The fixation times generally depend on the fixation temperature, depth and quality of the material. The Foron RD dyes exhaust on tone onto the fibre during the heating up phase and the dyebaths exhaust rapidly and completely on reaching the final temperature of 125-135°C.As a result the fixation times can be shortened compared to the Foron S, SE and E dyes.

Guide values for average dyeing PES qualities with Foron RD dyes:

DepthFixation time @125 deg C

Fixation time @130 deg C

Fixation time @135 deg C

Pale 0-10 minutes 0-5 minutes 0 minutes

Medium 5-15 minutes 5-10 minutes 5 minutes

Dark 10-20 minutes 10-15 minutes 10 minutes

V.Dark 20-30 minutes 20 minutes 10-15 minutes

The Foron S, SE and E dyes usually require 20-40 min longer than the Foron RD dyes atthe same temperature.

Cooling and draining the dyebath- Loose fibres, tops, yarn : After dyeing the bath should not be cooled below 90°C due tocrystallization of the oligomers, but drained hot- Piece goods on jet and overflow machines : After dyeing cool slowly (1-3°C/min) to80°C, then drain and rinse.

Silk Dyeing - properties of silk fiber

 

What is silk?Silk is natural protein filament produced by a caterpillar of butterfly - silkworm. It is a strong, soft thread neither phytogenous nor animal which is produced by a caterpillar before turning into a pupa (chrysalis).Silkworm is the most widespread insect-manufacturer on the Earth. It produces filament for taffeta, atlas, sateen, organza, and chiffon.

The noblest (and most expensive) silk is reeled off not boiled; its thread is pulled out from inside the cocoon.

To receive 3 kg of silk thread it is necessary to provide caterpillars with leaves of approximately 30 mulberry trees.

Artificial silk was invented only in the 19th century; before that only natural silk was used for fabrics manufacturing.

What is a cacoon? While a lot of people have probably heard about caterpillar Cocoons, they may not know for sure just what these are. Basically, they are nothing more than a protective casing that is around an insect. This is made of either silk or some other similar fibrous material that is then spun around the the insect during their pupal stage, which is the life stage of an insect that is undergoing transformation. While the most common type of Cocoon are those that are found around butterflies or moths, the egg case of a spider is also a type of Cocoon.

Usually an insect will enter into a Cocoon so that they will be protected from a harsh or unfriendly environment. This is why, most of the time insects will spend the wintertime in their Cocoons. So, as the days get shorter and cooler in the fall, these insects will start to spin a silky envelope around themselves. They will then retreat into this Cocoon and spend the winter without the need for food or water. 

You may be wondering just how these Cocoons are made. Well, they are actually made of silk. This silk is spun from 2 glands that are located inside of an insect. These glands are filled with a material that is thick and glue-like. An insect will then work in a figure 8 in order to wrap themselves up inside of this silk. This material is pressed out of the insect's 2 slender threads. These threads will then stick together as they emerge and then grow hard when fresh air touches them. 

This is a very interesting process because it has oftentimes been said that the most beautiful butterflies have actually emerged from the ugliest Cocoons. For this reason, many people consider the process of the Cocoon to be a miracle of nature itself. What is spider silk? Details of spider silk.Spider's silk is made up of chains of amino acids. In other words, it is simply a protein. The two primary amino acids are glycine and alanine.Spider silk is extremely strong -- it is about five times stronger than steel and twice as strong as Kevlar of the same weight. Spider silk also has the ability to stretch about 30-percent longer than its original length without breaking, which makes it very resilient.

How silk is produced? Silk - the most beautiful of all textile fibers is acclaimed as the queen of textiles. It comes from the cocoon of the silk worm and requires a great deal of handling and processing, which makes it one of the most expensive fibers also. Today China is the leading silk producer of the world. Other major silk producing countries include Japan, India and Italy.Production of SilkCharacteristics of SilkIdentifying of SilkFour Varieties of Natural Silk

The Silk Worm

 Production of Silk from Cocoon to FactorySericulture: The production of cocoon for their filament is called sericulture. The species Bombyx mori is usually cultivated and is raised under controlled condition of environment and nutrition. The life cycle of silk worm encircle in the four stages. The egg, the silk worm, the pupa and the moth. The silk worm which feeds on mulberry leaves forms a covering around it by secreting a protein like substance through its head.

 

This stage is called cocoon, the desirable stage for the silk producers.

Filature operations: The cocoons raised by the farmer are delivered to the factory, called a filature, where the silk is unwound from the cocoons and the strands are collected into skeins. Some cocoons are scientifically bred in such factories. The filature operations consist of the following stages.

a) Sorting cocoons : The cocoons are sorted according to the color, size, shape and texture as these affect the final quality of the silk. Cocoons may range from white and yellow to grayish.

b) Softening the Sericin : Silk filament is a double strand of fibroin, which is held together by a gummy substance called sericin or silk gum. After the cocoon has been sorted, they are put through a series of hot and cold immersions, as the sericin must be softened to permit the unwinding of the filament as one continuous thread.

c) Reeling the filament : Reeling is the process of unwinding the silk filaments from the cocoon and combining them together to make a thread of raw silk. As the filament of the cocoon is too fine for commercial use, three to ten strands are usually reeled at a time to produce the desired diameter of raw silk which is known as "reeled silk". The useable length of reeled filament is 300 to 600 m.

d) Bailing : The silk filament is reeled into skeins, which are packed in a small bundles called books, weighting 2 to 4.5 kg. These books are put into bales weighing about 60 kg. In this form raw silk is shipped to silk mills all over the world.

Characteristics of Silk

Silk is very strong in terms of tensile strength, meaning it can withstand a lot of pulling type pressure without breaking. This should not, however, be confused with wear ability or abrasion resistance. Silk will not stand up to the heavy wear that other fibers will.Silk can take on many different appearances. A raw silk fabric may fool you into thinking that it is cotton or synthetic. The more refined the silk and the smaller the yarn, the more it resembles the look and feel that we know as silky.Silk is a protein fiber like wool. This gives it many of its characteristics. It is sensitive to a range of chemical situations and cannot withstand prolonged exposure to either high alkalinity or to acid or oily soils. It will become brittle with age and exposure to sunlight.  

Identifying Silk

The burn test is the best way to be sure. Burning silk will leave a powdery ash and will extinguish itself when the flame is removed, just like wool. The easy way to tell silk and wool apart in the burn test is the smell. Where wool will have the smell of burning hair, the silk will have a much more disagreeable smell.

Four Varieties of Natural Silk

Out of the numerous species of silk moths, scientists have enumerated about 70 silk moths which are of some economic value. But of these only a very few have commercial value. The four commercially known varieties of natural silk are (1) Mulberry silk (2) Tasar silk (3) Muga silk and (4) Eri silk. Although the bulk of world silk supply comes from the silk moth Bombyx Mori which is domesticated, the other varieties of silk are known as wild silk, as they are grown in remote forest trees in natural conditions.

A wide range of silk fabrics are produced at different production centers   both Handloom and Powerlooms. A brief account of the range of fabrics is furnished below, as is known by its popular names.

Mulberry VarietiesSome important mulberry varieties are discussed below:(a) Plain Silk Fabrics

A range of thin silk to deluxe qualities are produced in this category using filature. Fabrics ranging from 20 gm to 70 gm are produced in this category using both handloom as well as powerloom. The fabrics is available as per the requirements in different shades as well as in checks and stripes. Beautiful pin stripes are a specialty for shirting. Plain silk is mostly used by exporters for making ladies blouses, fashion garments, made-ups and scarves. Deluxe and super deluxe qualities are also produced as per specific orders.

(b) Dupion Fabrics

A specialty of Bangalore Handlooms, Dupion is the craze of the west. Produced out of twisted filature warp and dupion weft is available in different quality ranges and shades. Dupion checks and stripes are elegant in look. Mainly used for dress material and cushion covers and furnishings, dupion is a popular name among the overseas silk importers.

(c) Charka Silk 

Using filature in warp and Charka in weft a thicker fabric is made on handlooms. For most of the zari decorative sarees charka yarn is popularly used by the sari manufactures.

(d) Chiffon

Using highly twisted yarn, a thin but strong fabric is produced on power looms, which after processing and finishing attains a soft and smooth texture. Chiffons are used for varied end-uses for ladies garments and scarves/stoles.

(e) Chinnon

This is also produced from highly twisted yarn of filature in power loom. After the final processing and finishing the fabric gets a soft but crimp effect. Chinnon is ideal for ladies dresses and scarves/stoles.

(f) Crepe

Produced from 2-ply twisted yarn of 's' and 'z' twist and woven on power loom, crepe is used for varied uses. Mysore crepe saris are very popular in domestic and export front.

(g) Organza

A very thin fabric produced from highly twisted yarn. After a starchy finish the fabric gets a rough texture. Organza is used as sari material as well as for embroidered garments.

(h) Satin

Silk satins are a popular variety of fabric used for a varied end use. When made into dresses satin gives an elegant Look. Banarasi Satin Saris are popular for export and domestic markets.

(i) Tabby Silk

A type of plain silk fabric produced in Kashmir. Tabby silk is mostly used for printed saris and scarves.

(j) Murshidabad Silk 

A popular silk fabric produced in the Murshidabad district of West Bengal. Used mainly for saris and scarves, the fabric is available in different qualities known as 16s, 18s, 20s, and so on .

(k) Matka Fabric

Using Matka yarn for both warp and weft, a thicker fabric is produced mostly for furnishing. The fabric mostly produced in Bhagalpur is a very popular export item at present. By using multiple yarns the texture and thickness of the fabrics can be modified according to the end use.

Wool - Chemical & dyeing properties

 

CHEMICAL REACTIVITY OF WOOLWool, in common with many other proteins, will react with a large range of chemicals. Wool contains three main types of reactive group: peptide bonds, the side-chains of amino acid residues and disulphide crosslinks. The chemical reactions involving these groups have been studied extensively and discussedin various textbooks.

The highly reactive nature of wool has enabled many industrial treatments to be developed, particularly in the areas of shrinkproofing, dyeing, bleaching, flame-resistance treatment and finishing.

ROLE OF FIBRE STRUCTURE IN WOOL DYEINGMechanism of wool dyeingWhen a textile substrate is dyed by an exhaustion method, the dyeing operation proceeds in three stages

1 diffusion of dye through the aqueous dyebath to the fibre surface2 transfer of dye across the fibre surface3 diffusion of dye from the surface throughout the whole fibre.

The fibre surface as a barrier to dyeingIn order to obtain satisfactory shade development and fastness properties, complete penetration of dye into the fibre interior is essential. The rate at which this occurs is controlled by the rate of dye diffusion across the fibre surface and then throughout the whole interior.

The above finding supports the view that the cuticle, probably the highly crosslinked A-layer of the exocuticle , is a barrier to dye penetration, in that dyes are directed to the gaps between the scales in order to reach the cortex. It appears, however, that lipids present at the intercellular junctions are also a barrier to the diffusion of dyes into the nonkeratinous regions of the cell membrane complex.

The intercellular mode of dye penetration applies to unmodified wool. Different dyeing behaviour may be shown by fibres that have been substantially chemically or physically altered, for example by reduction of the A-layer of the exocuticle, severe surface abrasion or complete removal of the cuticle.

Diffusion of dye in the cortexAfter initial penetration into wool fibres, dyes must diffuse throughout the entire cross-section in order to obtain optimum colour yield and fastness properties. Several workers have suggested that the continuous network of the cell membrane complex provides a pathway for the diffusion of reagents into wool. The vapours of organic solvents, the salts of zirconium and titanium and of chromium, and also phosphotungstic acid, all appear to penetrate the fibre by this route. It has been found that the cell membrane complex swells in formic acid to a much greater extent than does the whole fibre. They suggested that this disproportionatelyhigh swelling is the reason why dye is taken up very rapidly from concentrated formic acid.

As the dyeing cycle proceeds, dye progressively transfers from the nonkeratinous regions into the sulphur-rich proteins of the matrix that surrounds the microfibrils within each cortical cell. Dye also transfers fromthe endocuticle into the exocuticle, particularly the A-layer. It appears that the hydrophobic proteins located in these regions have a higher affinity for wool dyes than the nonkeratinous regions. At the end of the dyeing process the nonkeratinous regions, which were important in the early stages of the dyeing cycle, are virtually devoid of dye.

For nonreactive dyes, thermodynamic equilibrium with wool is not established until the process of dyetransfer into the keratinous regions is complete. This stage, which is not usually achieved until some time after the dyebath is exhausted, is the reason why a prolonged time at an elevated temperature is required to produce satisfactorily dyed wool. If dye remains largely in the nonkeratinous regions, rapid diffusion out of the fibre can occur and, hence, poor wet fastness properties are obtained.

Reactive dyes, however, may show a somewhat different equilibrium distribution between the nonkeratinous and keratinous regions of wool. Reactive dyes are capable of covalent bond formation with the proteins of the nonkeratinous regions, and therefore at equilibrium these dyes may be present in the cell membrane complex and endocuticle to a greater extent than their nonreactive analogues.

Jute Dyeing

 

 

Composition and Some Physical and Chemical Properties of Jute Fiber:

Physical Properties of Jute Fiber:

1. Density-1.47gm/cc2. Average Fineness-20 denier, i.e weight in gm. of 900 metres of filament3. Tenacity-4.2gm/denier4. Average Extension at break-1.2%5. Average Stiffness-330 gm/denier6. Average Toughness Index-0.027. Swelling water (area) 40%8. Specific heat 0.34 cal/g/c0 9. Specific internal Surface 10-200m2/g 10. Hygroscopicity (Average regain at 65% relative humidity)-13%

Some Chemical Properties of Jute Fiber

Holocellulose           82-85%Alpha Cellulose       58-63%Hemicellulose          21-24%Lignin                     12-14%Pactin                   0.2-0.5%                      Fat & Wax             0.4-0.8%Protein                 0.8-1.5%Mineral Materials    0.6-1.1%         

Jute is a ligno-cellulosic, composite natural bast fiber. Cellulose, hemi-cellulose and lignin are its major constituent components & its three dimensional structure is formed by different inter and intra-molecular forces resulted from various physical, chemical, and hydrogen bonds, between them. The commercial fiber consists of hairy strands of cylindrical networks of ultimate jute fiber. Properly retted and washed jute fibers are fairly lustrous with moderate strength but rough to touch. The color of the fiber also varies from creamy white to brown. 

Jute fabric or yarn can be dyed using the following dyes:

Dyeing

 Dyeing of jute fibres, yarns and fabrics with synthetic dyestuffs

Dyeing with direct dyestuffs Dyeing with acid dyestuffs Dyeing with metal complex dyestuffs Dyeing with reactive dyestuffs Dyeing with sulphur dyestuffs Dyeing with vat dyestuffs Dyeing with pigments Dyeing with natural dyes

Nylon Dyeing (Polyamide)

Polyester Dyeing:

Exhaust dyeing

1-2% Leveling Agent1-2gl Acetic acid

Raise to boil over 30-45 mins adding Acid dyes at B

Run for 40-60 mins at boil

Thoroughly rinse after dyeing to remove any loose colour.