Dyeing and Processing

Nike backs waterless dyeing | Dyes & Chemicals News

2012-02-08T22:44:00.000-08:00

Nike backs waterless dyeing | Dyes & Chemicals News
BEAVERTON – Nike has entered into a strategic partnership with DyeCoo Textile Systems B.V., a Netherlands-based machinery builder that has developed and built the first commercially available waterless textile dyeing machines that use CO₂ instead of water.
But with operating pressures for these machines reaching a massive 250 bar, can this technology really take off?

Colorfastness to bleaching:Peroxide

2012-02-03T03:59:00.000-08:00

This method is intended for determining the resistance of the colour of textiles of all kinds, and in all forms, to the action of bleaching baths containing peroxide in concentrations commonly used in textile processing.

A specimen of the textile in contact with adjacent fabrics is immersed in the bleaching solution, rinsed and dried. The change in colour and the staining .

for more details click here:http://www.dfmg.com.tw/member/standard/bs/BS-N02.HTM

Mineral and Clay Based textile bleaching

2012-01-29T03:39:00.000-08:00

Now a days many commercial products based on innovative clay or mineral chemistry are available for discontinuous bleaching of cotton and its blends with hydrogen peroxide. The clay or mineral technology have several advantages over conventional peroxide bleaching process.

What are these clay or mineral based products

(http://dyeingworld1.blogspot.com)

The clay or mineral based products are a composition of naturally occurring mineral or clays such as montmorillonite and/or bentonite in combination with suitable wetting , sequestering agents and viscosity control agents . The clay is finely dispersed in the form of a non settling, non separating emulsion which can be diluted with water and can be used easily. The clay structure is based on sheets. By separating these sheets e.g. by stirring, a very big surface is created This surface (till 800 M 2 per gram) makes it possible to absorb all kind of components like dirt, oil, greases etc. This gives an unique detergency effect .Two properties of montmorillonite crystals enable its use as a highly effective bleaching agent:

•On the one hand, impurities are adsorbed from the fabric and the liquor, due to the high specific surface area.

•On the other hand, montmorillonite has the property to replace disturbing heavy metal ions in the bleaching bath by Na-ions

The result is a dual effect as bleaching stabiliser and extractant.

How these products acts
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In water the clay particles are anionic charged and show a large adsorption effect for:

Hydrophobic waxes and oils

Metal ions (cation exchange capacity)

Hydrophilic materials and polymers

It is believed that the clay component provides both a scouring and softening effect, in essence by adsorbing organic contaminants and acting as an ion exchanger, in effect having a contaminant-suspending capacity. The powder or agglomerate particles of the clay divide into primary crystal plates caused by the swelling of the clay. The average size of the primary crystal plates is approximately 1.mu.. After being dispersed in the treatment liquor, the contaminants detached from the treated textile material are adsorbed by the clay particles, resulting in a greatly reduced redeposition of the contaminants. Textile incrustation is reduced due to the hardness elements released during washing having either become attached to the dispersed clay crystals or having been deactivated by the sequestrant. Clay, a natural product, washes off the treated textile material and forms an effluent having low BOD and COD values. The clay does not contribute to the BOD or COD values at all.(Ref: Clay-containing textile material treating composition and method by Brown; Harold M. (Lyman, SC))

The higher whiteness index of the treated textile materials is attributed to the fact that in this bleaching system the hydrogen peroxide is consumed to the maximum extent ,resulting into very low or zero residual peroxide.

Advantages of these single-component multifunctional auxiliaries are

(http://dyeingworld1.blogspot.com)

1.No need of Organic peroxide stabilizers,

2.No need of Dye bath Lubricants,

3.No need of Wetting and scouring agents

4.No need of Emulsifiers in most applications,

5.No need of Antifoaming agent.

6.No need of Machine cleaning aids.

7.Very low or no need of peroxide killer treatment.

8.Shortened bleaching cycle , less water and steam consumption.

9. Low loss of degree of polymerisation, due to controlled peroxide degradation

10.Better tensile strength compared with conventionally bleached fabric

11.Lower weight loss.

12, Better removal of oil or silicone

And since these products are derived from clay or natural resources these are eco friendly in nature , having low COD and BOD values

A typical bleaching recipe for cellulosic material is

(http://dyeingworld1.blogspot.com)

Best suitable for package dyeing machines , jets and winches .

1-2 ml/l Clay product

2-3 g/l Caustic flakes

2-5 ml/l Hydrogen peroxide 35%

At 95 -98 oC for 45-60 min

Test the peroxide content at equal intervals and ensure maximum utilization of peroxide , to optimize the process timing.

Followed by hot and cold wash, do peroxide killing if necessary.

Machine Embroidery

2012-01-27T02:09:00.000-08:00

Watch the slide show on textiles and click your favorite topic

Embroidery

Embroidery is the art or handicraft of decorating fabric or other materials with needle and thread or yarn. Embroidery designs are the way to add excellence and creativity to the garments and several other form of products. It is a way to give a professional and sophisticated outlook to the textiles. Embroidery design is used to create eye-catching effects and striking images on the garments, clothing and several forms of outfits and home textiles.

Hand Embroidery

The craft of hand embroidery has a long and interesting tradition and has bought many hours of creative pleasure to women for generations.

Machine Embroidery

Because the hand embroidery is a time consuming process and depends largely on the human skills , at the same time it is not possible to go for large scale commercial production of the same design . These disadvantages of hand embroidery led to the development of machine and now digital or computerized machines for embroidery. There are two main types of machine embroidery. The first, free-motion sewing machine embroidery, uses a basic zigzag sewing machine. The second, computerized machine embroidery, uses an embroidery machine or sewing/embroidery machine. With the advancement of computer technology, machine embroidery is improving very fast in its look and quality

Dyed on Dyed Embroidery

When the embroidery is done on a previously dyed fabric or garment either with in the same shade or in different shade or color combination.

Grieg on Greig embroidery

When the embroidery is done on either a greig or ready to dye fabric , which is then overdyed in different colors or shades , to produce articles of same embroidered patterns in different shades.

Selection of a good embroidery thread

Selecting the proper thread is achieved by first determining the end-use requirements of the embroidered products. Other factors that are considered include the type of material being embroidered, the type of embroidery machines being used, conditions under which the product must perform, and cost effectiveness.

Types of threads used in machine embroidery

1.Soft cotton threads are used where dull look is required or in traditional articles to match the outfit designs.

Mercerized cotton threads

2.Mercerized cotton threads have more lusture , more strength and clean finish , and higher dye pick up make them suitable to produce deeper and brighter shades.

3.Viscose rayon threads replace traditionally used silk threads . These have good shine, brighter shades and clean finish .

4.Spun polyester threads give the look of a cotton thread, but provide superior strength and durability. Polyester is colorfast, resistant to chemicals, and can be washed or dry-cleaned with most common cleaning solvents.

Polyester filament threads

Trilobal polyester is a multiple filament, twisted, high-sheen continuous fiber thread. It has the bright appearance of rayon or silk. If the desired effect is strength, durability, softness, and brightness, trilobal polyester is perfect for the job. It is wash, boil, and lightfast and also has a high resistance to chlorine and abrasion.

Others such as

1. Metallic threads ,

2. Aramid threads

3. Silk threads

4. Glowing or fluorescent threads in cotton and polyester.

5. Multi colored or tie and dye effect threads in cotton and polyester.

6. and polyester cotton core spun threads where core and sheath are dyed in different shades are used for specific needs and finishes.

Quality requirements for embroidery threads

It should have good strength
Good lubricity
Low on dry and wet shrinkage
Good over all color fastness
Evenly dyed
Free from knots , fluffs and thick and thin places.
TPI and Twist direction of thread as per the embroidery machine requirement.
Non Metameric ie the shade of embroidery thread should match the base fabric in different light sources or remain same in different light sources.

Selection of dyed threads for dyed on dyed embroidery

Proper Shade matching
Even dyeing within lot
Lot to Lot shade matching of embroidery thread as well as Fabric.
No shade change from sampling to bulk production.

The dyed on dyed embroidery option is considered where

When the substrate of fabric and embroidery thread is different eg polyester or rayon embroidery on cotton fabric and dyeing after embroidery is not possible.
When fabric and thread have same color but over dyeing is not possible due to smaller lot size etc.
A larger length of fabric is embroidered in multiple designs with same color thread in combination with others colors or qualities of thread.
In case of embroidery on finished garments .

Problems encountered in dyed on dyed embroidery fabrics

1. Shade matching is not proper from sampling stage to bulk production due to shade change of embroidery yarn and /or fabric in bulk production.

2. Shade mismatch in different light sources, due to metamerism.

3. Poor colorfastness of thread or fabric resulting into cross staining.

4. Lot to lot shade difference either in yarn or fabric or both.

5. Unlevel dyeing of embroidery thread.

Types of threads mainly used in greig on greig embroidery

The greig on greig embroidery is mostly done for 100% cotton fabric ,with 100% cotton or rayon embroidery threads.

This is suitable when,

When the fabric and embroidery yarn are dyeable with same dyestuff to produce a same shade.
Larger quantities of fabric are required with same shade of cloth and embroidery.
When a same embroidery pattern is repeated in different shades , the cloth is dyed in different shades after embroidery.

Problems encountered in overdyeing of greig on greig embroidery fabrics

Uneven dyeing if different qualities of embroidery threads are used simultaneously due to difference in dye pick up.
Shade difference in embroidery and fabric is observed when there is difference between fabric quality and thread quality is there , such as mercerized cotton fabric and soft thread or vice versa.
Shade difference between fabric and thread , due to difference in pretreatment of fabric and yarn such as greig fabric and RFD thread or vice versa.
Wrong quality of thread is used such as synthetic thread on cotton fabric.
Shade difference between embroidery due to mixing of different lots of embroidery thread such as different lots of mercerized threads.
Uneven dyeing of heavy embroidery patterns because if poor penetration of dyes in embroidered portions of fabric.
Uneven dye pick up of embroidered patterns due poor pretreatments such as scouring and bleaching and insufficient dyeing time for proper dye penetration and leveling .

Colorfastness requirement of embroidery threads

Good wash fastness :- The overall wash fastness properties of embroidery threads must be superior to the base fabric to avoid cross staining .
Good rubbing or crocking fastness
Good fastness to dry cleaning
High sublimation fastness in case of polyester threads
Good light fastness
Good chemical wash fastness :- fastness to chemicals such as chlorine or mild bleaching agents.

Problems in Garment Dyeing

2012-01-20T02:33:00.000-08:00

With today’s exploding clothing markets of leisure , casual wear and sports wear , garment wet processing has emerged as one of the best production routes towards meeting the quick changing fashion markets.

Unlike fabric or yarn as a substrate , a garment is not a uniform in texture ,it is full of thick places like seams , multilayered sites like pockets , cuffs and shoulders. At times certain unevenness like puckered seams lend a distinct style often highly valued but it could result into rejection of goods at other times .

Here we will try to figure out certain key problems associated with garment dyeing and their possible causes, so that a garment can analyze and overcome these problems.

Garment size control and appearance

variations in yarn size / twist
ends per inch
picks per inch
courses per inch in the knitted fabrics

Spirality in Knitted Fabrics

Twist of the yarn
Fibre parameters,
Yarn formation system,
Yarn geometry,
Knit structure
Fabric finishing.

Poor tear strength of garment

Degradation of cotton during
pretreatment,
dyeing and
finishing such as stone /enzyme washing.

Pilling

Low twisted yarns.
Use of low staple length, cheaper fibre in manufacture of yarns
Surface friction of fabrics/garments during wet processing and handling
Reworking of goods
Cylinder rotation is too high.
Liquor ratio is too low.
Excessive cycle time

Puckering of seams during dyeing

Improper selection of stitching thread.
Due to high twist in sewing thread
High residual and wet shrinkage of sewing threads
High stitching tension and improper stitch length..

Poor Rubbing fastness

Improper washing and soaping treatment after dyeing.
Too much unexhausted dye in dyebath.
Loosely held surface indigo dyes
Considerable back staining in each step
Exposure to atmospheric ozone

Poor light fastness

Use of reactive dyes which are not light fast
Use of formaldehyde based dyefixing agents

White, undyed or light seams

Use of improper thread such as polyester thread on cotton garments.
Use of mercerized thread on unmercerized garments.
Mixing of different types of threads such as mercerized and un mercerized .
High tension stitching .
Unmatched Shrinkage behavior of garment and thread .

Dullness around Metallic fittings

Corrosion and chemical reaction between metallic parts in
Pretreatment
Bleaching
Dyeing
Finishing

Streakmarks/ Lines / Creases

Overloading of machine
Friction between Garments
Entanglement of garments.

Shade nonuniformity

Differences in fabric preparation processes like

Desizing,
Scouring
Bleaching.

Inconsistency in the garment assembly

Poor Dye Yield

Garments contain a finish, softener, or an optical brightener.
Garments were allowed to dry out after pretreatment stage
Liquor ratio is too high.
Agitation is too slow.

Excessive washing between cycles.
Excessive time spent in any cycle.
Too much/too little pretreatment.
Not pretreated for correct time and/or temperature.

Blotchy or Non-Uniformly Dyed Garments

Garments contain a finish, softener, or an optical brightener.
Liquor ratio is too low (want 20:1).
Excessive bath temperature at beginning of pretreat or dye cycle.
Dye bath temperature ramped too quickly .
Improper addition or dilution of dyes/chemicals.
Live steam injection into bath.
Hard water.
Garments not scoured properly
Garments were allowed to dry out after pretreatment stage
Garments not allowed to wet-out sufficiently before adding pretreatment.

Patchy dyeing

Starting temperature too high
Heating rate too High
Salt addition at high temperature
Addition of dyes and chemical at once

Spotting

Formation of foam
Improper washing
Machine not clean.
Excess pretreat not rinsed from garment before dyeing.
Dye not properly diluted or stirred before bath addition.
Incompatibility of auxiliaries.

Harshness

Insufficient size removal
Use of high quantities of alkali
Poor softner application

Smell

Acetic acid,
Residual chlorine,
Cationic softners

Back staining

Improper maintenance of

pH
Temperature

Blotchy / unlevel dyeing in pigment dyeing

Improper preparation
Higher dosage of cationic reactant
High rate of rise in temperature during Cationization
Direct contact of steam with garment
Too low MLR hence uneven build-up of Cationizer

Batch to batch shade reproducibility in Pigment dyeing

Change in pH during cationization

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Polyester dyeing in HTHP dyeing machines

2012-01-16T01:39:00.000-08:00

Important factors: polyester dyeing in HTHP dyeing machines.
1.Water quality

Traces of soluble copper and iron salts can affect the shade of some disperse dyes quite markedly due to the formation of coordination complexes.The presence of calcium and magnesium cations can interfere with the anionic dye dispersing agents/leveling agents and wetting agents present in the dyebath. To overcome these problems a small amount of chelating agents might be added to the dyebath.

2.pH of the dyebath

Ideally the pH of the dyebath should be buffered by use of a quality pH regulator, in the range of 4.5-5.5 to minimize the possibility of dye hydrolysis.

3.Use of Surfactants in dyeing

There are a multitude of purposes for which anionic surface active agents are used in dyebaths, such as wetting, penetrating and deareation etc. anionic surface active are also used to stabilize the diluted dispersions of the dye.This is necessary particularly when dyeing paler shades where dyebath concentration of surfactant introduced with the dye itself is small.

The non ionic surfactants are generally used to control the rate of exchange of dyebath to the fiber.

4.Temperature
For most cost effective dyeing of polyester depends on factors such as starting temperature ,rate of heating ,dyeing temperature and duration of dyeing which should result into well exhausted bath ,satisfactory color uniformity and batch to batch shade consistency.
A general rule of thumb , the starting temperature of dyeing is 70-80 degrees , the rate of rise of temperature is 1.5-2 deg.Celsius /min and the dyeing temperature is between 115-135 deg.Celsius.
5.Time

For an ideal dyeing time selection , one must take into account the exhaustion of dye bath , uniformity of the dye , satisfactory color penetration , for good color fastness and reproducibility of the dyeing results. Generally 15-60 minutes of dyeing time is followed and it is not necessary to prolong the dyeing long beyond the time of maximum exhaustion.

6.Dyes

The dyes with similar dyeing characteristics must be selected for particular formulation, it is important to identify the actual dyeing rate of each component will be dependent on the concentration present in the formulation.Care should be taken that the dyeing conditions allow the slowest dyeing component to reach the effective equilibrium.

7.Oligomers

Typically polyester fibres contain between 1.5 and 3.5% by mass of low molecular esters, the principal oligomer being cyclic tris(ethylene terephthalate) with smaller quantities of a dimer, pentamer as well as traces of other compounds.

when oligomers are released from the polyester fibre, after some time
at 130° C, if an efficient dispersing agent not present in the bath to prevent crystallization of the oligomers, and to prevent small particles of oligomers coming together to form larger agglomerates, oligomers will deposit on the yarn and the machine.

Dispersing will maintain the oligomers in a fine dispersion so that when the machine is drained more oligomer goes down the drain. Discharging the dyebath at high temperature if this is possible can also reduce oligomer deposition because any of the material soluble during dyeing at a high temperature can precipitate during cooling.
8.Reduction Clearing
Reduction-clearing treatment is necessary to remove any dye remaining on the fibre surfaces, If not removed, this surface contamination can undermine the brightness of shade as well as the wash, sublimation and crock fastness results.Commonly, the dyed polyester is cleared of surface-deposited dye as well as auxiliaries (e.g. carriers, surfactants) by means of treatment with detergent or reductive or oxidative treatments, in order to secure optimum fastness of the dyeing and also to improve the brightness of shade.
The usual treatment carried out, especially in heavy depth, is reduction- clearing, where the dyed fibre is treated in a strong reducing bath, usually made up of sodium dithionite and caustic soda. A treatment for 20 minutes at approximately 70-80 deg Cel, is often sufficient to clear
the fibre surface, but the ease of removal varies from chromophore to chromophore and dye to dye. This treatment acts to destroy loose azo disperse dye through chemical reduction of the azo link . Anthraquinone disperse dyes are not fully destroyed by such a treatment but a degree of removal of surface dye is achieved through temporary solubilisation of the disperse dye to the alkali-leuco form.

9.Stripping
Stripping of disperse dyed material can be accomplished by treating goods
a. In a blank bath containing non ionic leveling agent at 130 deg.cel.
b.For chemical destruction of dye use 1-2 gpl NaOH and a reducing agent
or mild acidic treatment with zinc sulfoxlate-formaldehyde or sodium chlorite can reduce the shade to almost a off white back ground.

A New Study on Stripping for Polyester Fabrics

10.Prolonged treatment of polyester in alkaline solutions

Prolonged treatment of polyester goods in alkaline solutions will cause weight loss due to hydrolysis of polyester at the fiber surfaces, since the fiber surface has been eroded considerably after a long alkaline treatment it is very difficult to rework the goods to give them originally anticipated appearance.

Useful Auxiliaries and Ingredients Used in Textile

Q&A Session for Overview of Dye Classes and Methods of Coloration Webinar.

Problems with oligomer in dyeing polyester yarns and fabrics.

Dyeing with Disperse Dyes

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Levelling agents

2012-01-13T23:41:00.000-08:00

in every dye house ,levelness of the dyeing is a major criteria , since unlevelled goods are usually not saleable ,causing loss to the manufacturer.

Leveling
Migration of applied dyes in a uniform manner throughout the dyed goods is called leveling and it may be a property of the dye or it may require some chemical assistance (of leveling agents which are dye bath additives
to promote level dyeing)
Levelling agents are invariably surfactants ;they may be anionic ,cationic,non ionic or amphoteric in nature .some times combinations of these are also used ,There are two fundamental mechanisms that can contribute to a level dyeing:

1.Control of rate of exhaustion of the dye so that it is taken evenly and slowly.

2.Migration of the dye after initial uneven sorption on the fiber.

In complex formation the principle of leveling is usually the same ,irrespective of whether non ionic or ionic agents are used , although the mode of complexing is different.

The attractive forces between leveling agent and dye creates a counter balancing mechanism against dye fiber attractive forces,restraining the uptake of dye by the fiber.

As the temperature of the dyebath increases , the complex gradually breaks down ,progressively releasing dye for more gradual sorption by the fiber.

further reading :-Role of leveling agents in textile wet processing
Explore for more information on leveling agents

How to Test pH of Textile material

2012-01-12T22:54:00.000-08:00

Testing of pH by water extraction method

Purpose of the test

The pH of the processed textiles must be neutral and within the prescribed limits for a particular end use. The textiles with higher pH value may exhibit yellowing tendencies ,create change of shade upon storage and during shipment, result into poor dye pick up , patchy dyeing and poor colorfastness. very high and very low pH results into degradation of textiles during storage and use , may result into poor softness and harsh feel. pH of apparel fabrics which are in direct contact with the skin or used for baby wear, must be controlled not to make the skin itchy.

The pH control is very important for in process quality as well as quality of the finished material.

Test method

Boil 250 ml distilled water or deionized water for 10 minutes and put 10+/- 0.1 gm of test specimen in it boil for another 10 minutes. Allow it cool down to room temperature , remove the specimen and squeeze back the excess water in the beaker.

Test the pH by using a calibrated pH meter within an accuracy of +/-0.1 on pH scale.

The pH of water extract must be tested after prior to dyeing if you are getting uneven dyeing and to be tested after completion of dyeing and soaping to avoid any problems in finishing such as softening and dye fixing etc.

This information is generalized for day to day in house process control, for detailed information please follow AATCC 81-2006

and ISO-3071.
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pH and pH buffers

2012-01-10T02:43:00.000-08:00

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. definition: pH is the negative logarithm of the hydrogen ion concentration. pH is a measure of the concentration of hydrogens ions ( H⁺ions or protons) in a solution.

pH scale

The pH scale was defined by Sören Sörensen, Danish biochemist, in 1909The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic and a pH more than 7 is alkaline.

Measuring pH

Measuring pH is essential not only in finding the chemical characteristics of a substance but also as the first step toward managing chemical reactions.

Measuring pH involve either the use of pH measuring electrodes or indicators whose colors are dependent on pH. A pH meter measures the difference in potential between a reference electrode insensitive to changes in pH and an electrode sensitive to such changes.

pH indicators based on color changes are normally used in the form of pH papers. The paper is wetted with the solution being measured and the resulting color is compared with color standards to determine the pH.

In the textile industry, measuring pH is important in product testing, pretreatments,dyeing and finishing processes.

pH buffers

A pH buffer is a substance that resists a change in pH when small amounts of an acid or a base are added to it. The pH of a buffer changes very little when small amounts of an acid or a base is added to the buffered solution. A buffer consists of approximately equal amounts of conjugate weak acid/base pair in equilibrium with each other . Strong acids and their conjugate bases do not produce a buffer since in strong acid ionization is complete and there is no equilibrium.

Why pH changes during a Textile dyeing process

Water quality
Reaction products
Additives during the process
Time
Temperature
Contaminants in the substrates.

Some pH buffers systems useful in textile pretreatment , dyeing and finishing.

HCl and sodium citrate pH 1-5

Citric Acid and sodium Citrate pH 2.5-5.6

Acetic Acid and Sodium Acetate pH 3.7-5.6

K₂HPO₄ and KH₂PO₄ pH 5.8-8.0

Na₂HPO₄ and NaH₂PO₄ pH 6-7.5

Borax and NaOH pH 9.2-11

pH in textile coloration

Most of the dyeing processes requires a controlled pH , such as slightly alkaline in direct dyes , strong alkaline in reactive , vat and azoics , acidic in disperse and basic dyes strongly acidic in acid dyes etc.

The control of pH in textile processing is ensured by fundamentally three different techniques , such as

The maintenance of a relatively high degree of acidity or alkalinity .
The control of pH within fairly narrow tolerances mainly in near neutral regions.
The gradual shift of pH as dyeing proceeds.

Many processes of textile processing are pH dependent.

Scouring of cotton in highly alkaline conditions
Bleaching of different substrates where pH has to be maintained for proper bleaching action.
Solubilising the dyestuffs.
Exhaustion and fixation
Oxidation
Stripping
Finishing

further reading
pH of textiles by water extraction method

Testing of common salt

2011-12-23T22:22:00.000-08:00

Testing of common salt (for dyeing purpose)

Salt in textile dyeing is mainly for exhaustion of dyes from the dye liquor to the substrate. It is also used in the water softening process to regenerate the zeolite .The salt used must be good quality , with low water hardness causing salts, minimum insoluble material and free from metal salt impurities.

Following common tests are done to ensure the good salt quality,

1.Moisture content

2.Dust or insoluble impurities

3. Water hardness caused by water when used in dyeing.

4.% purity of salt.

Moisture content :-

is tested by using a moisture meter or by drying and pre weighed sample in hot air oven .

Dust or insoluble impurities :-

By taking about 100 gms of dried salt sample and dissolve it 250 ml distilled water , allow the insoluble to settle down and then filter it with whatman filter paper no.40. dry and weigh the residue to find out the percentage .

Water hardness :-

Since salt is used in large quantities in reactive dyeing , therefore water hardness caused by salt affect the overall dyeing quality , therefore salt must be tested for water hardness .

Make a solution of 100 gpl salt and test it for water hardness , by using standard EDTA solution.

Purity :-

Take about 6 gms of sample accurately weighed and dissolved in distilled water , made upto 1 ltr. Take 50 ml aliquot and titrate it with 0.1 N silver nitrate solution using 5 % potassium chromate solution as indicator till a reddish orange tinge is obtained.

1 ml of 0.1 N silver nitrate = 0.005845 gm of NaCl

Quality parameter of Salt for Dyeing

pH of aq. Solution = neutral

Calcium = maximum 100 mg /kg

Magnesium = maximum 50 mg/ kg

Iron = maximum 0.01 mg/kg

Copper = not detectable

Hardness of 80 gpl solution = maximum 50 ppm

Moisture content = maximum 0.25 %

Insoluble dust = maximum 0.25%

Hair Colors

2011-12-22T23:18:00.000-08:00

Why coloring hair

Because it is the one thing that can dramatically change our appearance If we don't like the way we look! Also, it is quite fun to change it. I do agree that most of the time we look the best with our natural color. There are few reasons that why we want to dye hair,

(1) We want to lighten our hair more than three shades,

(2) We have dark hair and want to dye to make them light or ,

(3) We have natural light brown or blonde hair and want to dye it,

(4) We are re trying to fix a problem,

(5) We have light hair and want to make it darker.

(6). Many people think that gray is the first sign of aging and the end of his youth, so they go for hair coloring.

Natural hair dyes

Hair dye is one of the oldest known beauty preparations, and was used by ancient cultures in many parts of the world. Records of ancient Egyptians, Greeks, Hebrews, Persians, Chinese, and early Hindu peoples all mention the use of hair colorings. Early hair dyes were made from plants, metallic compounds, or a mixture of the two. Rock alum, quicklime, and wood ash were used for bleaching hair in Roman times, and herbal preparations included mullein, birch bark, saffron, myrrh, and turmeric. Henna was known in many parts of the world; it produces a reddish dye.

Many different plant extracts were used for hair dye in Europe and Asia before the advent of modern dyes. Indigo, known primarily as a fabric dye, could be combined with henna to make light brown to black shades of hair dye. An extract of the flowers of the chamomile plant was long used to lighten hair, and this is still used in many modern hair preparations. The bark, leaves, or nutshells of many trees were used for hair dyes. Wood from the brazilwood tree yielded brown hair dyes, and another hair dye known in antiquity as fustic was derived from a tree similar to the mulberry. Other dyes were produced from walnut leaves or nut husks, and from the galls, a species of oak trees. Some of these plant-derived dyes were mixed with metals such as copper and iron, to produce more lasting or richer shades.

Synthetic hair colors or dyes

In general, hair dyes include

1.Dyes,

The dye chemicals are usually amino compounds, and show up on hair dye ingredient lists with such names as 4-amino-2-hydroxytoluene and m-Aminophenol. Metal oxides, such as titanium dioxide and iron oxide, are often used as pigments as well.

2.Modifiers,

Modifiers stabilize the dye pigments or otherwise act to modify the shade. The modifiers may bring out color tones, such as green or purple, which complement the dye pigment. One commonly used modifier is resorcinol, though there are many others.

3.Antioxidents,

Antioxidants protect the dye from oxidizing with air. Most commonly used is sodium sulfite.

4.Alkalizers,

Alkalizers are added to change the pH of the dye formula, because the dyes work best in a highly alkaline composition. Ammonium hydroxide is a common alkalizer.

5.soaps, .ammonia, wetting agents, fragrance, and a variety of other chemicals used in small amounts that impart special qualities to hair (such as softening the texture) or give a desired action to the dye (such as making it more or less permanent).

6.Developer

The developer is most often based on hydrogen peroxide, with the addition of small amounts of other chemicals depending on the manufacturer.

Temporary Hair Dye

Temporary or semi-permanent haircolors may deposit acidic dyes onto the outside of the hair shaft or may consist of small pigment molecules that can slip inside the hair shaft, using a small amount of peroxide or none at all. In some cases, a collection of several colorant molecules enter the hair to form a larger complex inside the hair shaft. Shampooing will eventually dislodge temporary hair color. These products don't contain ammonia, meaning the hair shaft isn't opened up during processing and the hair's natural color is retained once the product washes out.

Semi-Permanent Hair Dye

This product adds color without changing natural color dramatically. The hair color contains tiny color molecules that enter the hair's cuticle, or outer layer, and go into your hair's cortex. They don't interact with your natural pigments. And since the molecules are small, they eventually exit the hair shaft after several shampoos, leaving the hair as it was before treatment.

Permanent Hair Dye

Permanent Hair Dye molecules enter all the way into the cortex, where they react and expand to a size that cannot be washed out. These dyes acts to lighten the hair's natural pigment to form a new base and then to add a new permanent color.

Structure of Human hair

Hair is made of strong elastic strands of protein called keratin and in chemical terms is composed of oxygen, iron, nitrogen, hydrogen, sulphur, carbon and phosphorus.

Each hair is constructed in three different layers: the cuticle, the cortex and the medulla.
The cuticle is the outermost layer of the hair which provides protection to the inner cortex layer. Improper care and frequent use of harsh chemicals on hair damage the cuticle.

The cortex is the second layer. . The cortex is composed of fibres twisted together like a rope. It is the cortex which gives the hair its colour. The presence of the four natural pigments black, brown, yellow and red are logged in the cortex in varying proportions, and the air spaces in the cortex determine the colour and shade of hair.

Lastly, the medulla is the unimportant innermost layer which is composed of soft keratin..

How hair colors work

The outer layer of the hair shaft,(cuticle) must be opened before permanent color can be deposited into the hair. Once the cuticle is open, the dye reacts with the inner portion of the hair, the cortex, to deposit or remove the color.

Most permanent hair colors use a two-step process (usually occurring simultaneously)

First removes the original color of the hair
Second deposits a new color.

Ammonia is the alkaline chemical that opens the cuticle and allows the hair color to penetrate the cortex of the hair. It also acts as a catalyst when the permanent hair color comes together with the peroxide.

The developer( peroxide) removes pre-existing color. Peroxide breaks chemical bonds in hair, releasing sulfur, which accounts for the characteristic odor of hair color. As the melanin is decolorized, a new permanent color is bonded to the hair cortex. Various types of alcohols and conditioners may also be present in hair color. The conditioners close the cuticle after coloring to seal in and protect the new color.

Health risk and hair colors

Use of hair dye has been linked to allergic reactions, respiratory disorders and even cancer. Harmful ingredients used in hair color and hair dyes ,Hair dyes contain heavy metals that can be harmful. Ingredients in hair dyes are toxic and cause irritation to the eyes, skin and mucous membranes to hypersensitive people.

Para-phenylenediamine and tetrahydro-6-nitroquinoxaline, both have shown to damage genetic material and cause cancer in animals. Allergic reactions from PPD are known to cause facial and neck swelling. Inhalation is likely to bring about coughing, sneezing and shortness of breath, and respiratory problems in extreme cases. Skin contact with PPD may cause rashes and eye contact irritation, redness and pain.
Coal tar, a known carcinogen is used in hair colors and dyes as it creates brighter and more lasting colors than other organic vegetable dyes.
Formaldehyde is a preservative linked to cancer, developmental and reproductive toxicity and more.
DMDM Hydantoin, another preservative is a known immune system toxin (and has been restricted for use in cosmetics in Japan).
Eugenol is a fragrance ingredient that’s associated with cancer, immuno toxicity, neuro toxicity and allergies
Ammonia exposure to high levels of ammonia can cause irritation and allergy, hair loss problems and scalp dermatitis.
Hydrogen peroxide Hydrogen peroxide bleaches your hair and thus damages it. But the extent of the damage will depend on its level of concentration..

Dyes and color index( CI) numbers

2011-12-22T04:04:00.000-08:00

The color index is produced jointly by SDC (Society of Dyers and Colourists) in the UK, and the AATCC (American Association of Textile Chemists and Colorists) in the USA. The index is split into two parts: one part gives the commercial names for the individual dyes; the other part of the index gives the color index number, and lists the commercial names for the dyes using that number.

Color index number

Every dye is given a color index number based on its chemical type. The same number is given to the dyes with the same chemical structure. For example, Resolin Red FB and Dispersol Red B2B, both have the color index number “CI Disperse Red 60." The index number is divided into four sections:

1) CI stand for color index and is displayed in every color index number 2) The next section is the dye type, e.g., Disperse, Acid, etc.

3) The third section is the color, according to a defined list of color names, e.g., Red Yellow, Orange

4) The last number is increased every time a new dye is added to the index; in the example above, “CI Disperse Red 60" is the 60th red disperse dye to be added to the index.

As an extensive international compilation of the structure and properties of dyes and pigments, as well as a system of numbering these materials, the Colour Index is a potentially valuable tool for all users of colorants.

CAS numbers for chemicals and chemical compounds

CAS Registry Numbers are an important tool for substance searching. These are unique identifiers assigned by the Chemical Abstracts Service (CAS) to specific substances identified by them in the chemical literature.

Registry Numbers save you from having to think of all the different synonyms, trade names, or possible systematic names when you are doing a compound search by linking them all into a single search term.

For example, there are over 20 synonyms for formaldehyde, e.g., methanal, formalin, methyl aldehyde. The CAS Registry Number for it, 50-00-0, is specific to all those names for the same compound.
"The foam retracts above the legible symphony."

Textile Jobs

2011-12-01T23:30:00.000-08:00

Denim pollution

2011-05-27T02:52:00.000-07:00

People around the world share one fashion love “blue jeans.” Denim may be stylish, but also has many unexpected downsides pollutants.Two techniques commonly used that became the hallmarks of blue jeans are the well known indigo color and the worn out look that make the statement in a pair of jeans. Unfortunately, the chemicals involved in their processes contribute to pollution. Today the indigo dye is produced from coal or oil (a process that can release toxic byproducts like cyanide and formaldehyde) while stonewash uses volcanic rocks or pumice stones which releases pumice dust that endanger worker’s health and produces gritty sediment waste.

http://cnn.com/video/?/video/world/2010/04/26/chang.blue.jeans.cnn

Dyeing Cationic Dyeable Polyester (CDP) with Cationic Dyes By Michael Hilton

2011-01-20T02:24:00.000-08:00

This article is contributed by Michael Hilton

Cationic Dyeable Polyester is a special Polyester fiber which has undergone a change during polymerization. They were built of molecules of 5 - sulphophthalic acid, to generate anionic sites that the fibers of normal PET not have. Having anionic groups it can also be dyed with cationic dyes with results of high brilliance. However, these fibers can be dyed with disperse dyes. Compared to ionic dyes, disperse dyes have smaller molecular extinction coefficients and lower build-up property, so these dyes cannot give bright and deep colors. This type of fibers were born also to lower the Tg (glass transition temperature) of the polymer, 10 ° C lower than normal Polyester fibers, so to obtain a more segmental mobility and open polymer structure. Resulting in increased rate of diffusion of the dye in the fiber at a lower temperature. Tg Range (70 – 85°C). This modified polymer is also more easily hydrolised and more sensitive to heat setting before dyeing at a maximum temperature of 180°C.

Example

scouring and dyeing exhausted process in Overflow – Jet Machine (Liquor ratio - 1:10 – 1:20) :

Scouring:

Continuous washing cold for 10 min

drain well (for water soluble oils)

Fill with water 30 ° - 35°C

0,5 g/l Antifoam (preferably non-silicone) alone

1 g/l Detergent non – ionic

0,5 g/l Caustic Soda 36° Bè

Raise to 80°C quickly and hold for 20 – 25 min

Drain well

washing cold for 10 min

and after starting in dyeing

Dyeing with Cationic dyes

Follow the Graph below :

The dyebath is set at 60°C - introduce order

0,5 g/l Antifoam (alone)

6 g/l Sodium sulphate (only dyeing at 120°C) (1)

1 g/l Dispersant non-ionic

X g/l Acetic Acid pH = 4,5

X % Levelling – Carrier anionic (only dyeing at 98°C)

X% Cationic dyes (dissolved at 60°C with 1 g / l of acetic acid) - (introduce preferably dosed curve progressive Sen +)

Then raise to 70°C - after to 85°C at 0,5°C / min (while the fiber is softening) and hold for 10 min, after raise to 120° (or 98°C) at 0,6°C / min – hold for 30 – 60 min (depends on the depth of the color)

then cool to 70°C at 0,5°C / min and check the color.

Please note that sodium sulphate (Na +), being very stable at high temperatures, is the protector of te anionic sites sensitive to the acid at 120 °C.

After dyeing, the dyed samples were rinsed and washed with 2 g/l of non-ionic detergent at 60 – 70°C.

Light fastness: moderate to good

Washfastness: good to excellent

Rubbingfastness: good

Excellent resistance to sublimation on wet

No fouling of lycra mixed

Report Writing for an Effective Project Report: Project Reports Must be Clearly Structured for Maximum Reader Impact

2010-04-15T23:10:00.000-07:00

Report Writing for an Effective Project Report: Project Reports Must be Clearly Structured for Maximum Reader Impact

2010-04-15T23:08:00.000-07:00

Report Writing for an Effective Project Report: Project Reports Must be Clearly Structured for Maximum Reader Impact

Polyester Microfibers:- Dyeing and Wet Processing

2010-04-09T02:50:00.000-07:00

Microfiber

A synthetic fiber that is extremely soft, lightweight, breathable, durable and ultrafine. In fact, microfibers are two times finer than silk and one hundred times finer than a human hair. Microfiber is currently manufactured from acrylic, nylon, polyester and rayon.Ultra-microfibers on the market are even finer – some having thickness of just 1/200th the thickness of human hair!

Microfibres refer to staple fibres, or individual filaments within yarns, which have fineness less than 1 decitex ( 1 grams per 10,000 meters) and For any fiber to be classified as microfibre yarn, the weight per 10,000 metres of yarn (dtex) is divided by the number of filaments (f), the result must be below 1.
All about microfibers

Microfibers: Functional Beauty

Properties of Polyester Microfibers

Lightweight and flexible
Good stability and shape retention
Anti-wrinkle property
Have a wicking ability that permits perspiration
Comfortable to wear as they are more spongy
Doesn't water stain - superior water repellency is available
Woven or knitted into a very high quality fabric construction
Formerly commenced as a polyester microfiber, today you can find nylon, rayon and acrylic microfibers too.
Strong and durable, water repellent and wind resistant -so tightly woven, that the fabric can't be penetrated by wind, rain or cold
Lightweight, resilient or resist wrinkling, have a comfortable array, preserve shape and resist pilling
The positively charged microfibers draw dust; the tiny fibers are capable to enter the microscopic surface voids most materials
Washable, dries quickly and also washable in at the water temperatures up to 200 degrees and their characteristics will remain intact.
Electrostatic effect - Hair, lint and other dust particles are attracted and grabbed by the microfibers without lifting dust.
The density of the material allowable it to grip six to eight times its weight in water hence high absorbing power capacity
The attraction capability of the microfibers is so sound, even absorbs bacteria and germs - hence can be use as germ or bacteria free purpose
The fabric consists of millions of small tiny conduits that carry oil and grease too.
Benefits of microfibers
Comfortable - very soft, texture like silk, lightweight
Due to its fineness and superior fiber surface area making deep, rich and bright colors achievable
Less "sweaty" in warm weather than usual synthetics
Quickly cleanable - clean just with water
Highly intense and shrink-resistant
Presents insulation and breathability
Change without help - to establish lovely drape
Very fine - finer than the most precise silk
More reusable for cleaning alternative - compared to other mops more efficient and long life

Dyeing of polyester Microfibers
Due to their fineness, the total surface area of microfibre yarn or fabric is far greater than ordinary fibres. Threfore

1.Due to its special structure ,micro fibers has much larger quantity of size ,oil agents and wax on warp yarns.

2.Since microfibres have very small interstitces, with consequent difficulties of size accessibility and duffusibility, desizing becomes quite difficult and costly.

3.Microfibres have greater absorption area resulting in a dyeing rate four times higher than that of normal, which can cause unlevelness in dyeing.

4.They also require more dyestuff than standard fibres to obtain the same depth of shade.
5.Larger external surface means an increase in number of threads exposed to light which, on destruction of dye, is expressed as lower light fastness rating.
6. Wash fastness and color fastness to rubbing is also poor.
7.Staple microfibres offer difficulty in carding.

The problems in wet processing of microfibers can be overcome by

1.Better knowledge about the size applied and optimum parameters during desizing operation.

To achieve satisfactory dyeing effects ,desizing and refining process must be done before dyeing and after desizing and refining , there should be no impurities left such as electrolyte, antistatic finishing agent , spin finishes and blot.

2.Pre-setting

Suitable pre setting conditions ( time ,temperature and tension) helps not only in stable dimensional stability ,softness but also better dyeing results.

3.Alkali weight reduction

Alkali weight reduction s to treat the fabric with concentrated alkali at high temperature.fber molecule hydrolyse under this condition and lose some weight with change in properties, thus space occurs between crossing points and rubbing resistance relative to slippage among yarns becomes small.Alkali weight reduction makes fabric soft, liveliness, limber and improved absorption.

2.Careful selection of the dyes.

Proper dye selection which are
1.Compatible
2.Having same exhaustion rates
3.Having high wash fastness properties.
4.Good migration and levelling properties
eliminates problems regarding build-up and fastness properties.
Disperse dyes for polyester microfibers

3.Optimizing the dyebath conditions and dyeing cycle.

Optimised dyeing cycles can be worked out by controlling the temperature to account for the high rate of dyeing and to eliminate the risk of uneven dyeing.Chemicals and dyes to be added at, at least 10-20 deg.C lower temperature than normal polyester fiber dyeing. The additions of dyes must be progressive or devided at least into 4 parts. The heating rate must be slow from 40 deg C to 100 deg C. 10-20 min more holding time required at 130 deg C as compared to normal PES.

4.Proper selection of Dyeing machinery.

The dyeing machine must have the required automation to fufil the requirements of microfiber dyeing such as microprocessor controlled dosing , proper and accurate heating rate control etc.

5.Proper selection of dyebath additives
such as
Levelling agents :- A strong levelling agent which shall start working at lower temperatures.
Dispersing agents :- Higher quantities of dispersing agents are needed because amount of dyes required are more to produce the desired depth.
Chelating agents:-
Anticreasing agents,Dyebath softners/Lubricants :- Because microfiber textiles are prone to creasing , therefore use off dyebath lubricants is must.

6.Proper aftertreatment of dyed goods.
Soaping :- In order to obtain satisfactory color effect , fabric should be soaped after dyeing .Soaping is the key process to achieve satisfactory dyeing results on polyester especially polyester / nylon microdenier fabric.

Reduction clear :-Good reduction clear process is needed to achieve satisfactory washing , rubbing and light fastness properties.
Washing :-Is required for neutralising and removing alkali after reduction clear treatment.
Softening, anti soil and antistatic treatment :-Because microdenier fiber easily stains and produces static charges, a hydrophilic ,antistatic and antisoil treatment besides softening is highly recommended to ensure fabric softness and comfortability.

Recommended Dyeing Cycle for polyester Microfibers

Dianix PLUS( Dystar) or Longsheng is a new range of five compatible, level-dyeing dyes for reliable dyeing of medium and heavy shades, especially on microfiber and weight-reduced polyester, whether applied under mild alkaline conditions to control trimer, or under conventional acid conditions.
Dianix E-PLUS" for Pale Shades on Polyester Fabrics
Fashion application of polyester

Application of polyester Microfibres

Microfibers are most commonly found in polyester and nylon. Some rayon and acrylic micros are in production and available to consumers. Micros can be used alone or blended with conventional denier man-made fibers as well as with natural fibers such as cotton, wool, and silk.

In textiles

Microfibers are used in a variety of fabrics, but most commonly in dress and blouse weight garments. Suit jackets and bottom weights are becoming available. Look for micros in lingerie, rainwear, outdoor fleece and wind-resistant sportswear, as well as tents, sleeping bags, track and jogging suits. The strength of microfibers make them particularly adaptable to sueded or sandwashed finishes because of their extensive fiber surface area and the use of strong fibers like polyester and nylon. As a result, many microfibers simulate the appearance of sandwashed silk.

Other Main products for which microfiber are ideally suited:

Microfiber Glass Cloth

Duster/Multi-purpose Microfiber Cleaning Cloth

Microfiber Scrubber

Microfiber Kitchen Cloth

Microfiber Optical & CD Cloth

Microfiber Mops

Microfiber Cleaning Sponge

Microfiber Cleaning Cloths – Terry Cloths, Suede Cloths, Waffle-Weave Cloths

Microfiber Makes the Grade
http://www.tex.in/education/nextiles/fib/mic/mic.html
http://ygmfranchise.blogspot.com/2007/07/cleaning-tips-microfiber.html
http://www.microfibergreen.com/is-microfiber-green-product.html
http://www.norwexnow.com/microfiber%20science.html

Sublimation Fastness Of Disperse Dyes

2010-04-05T22:52:00.000-07:00

Sublimation is the process of phase change from solid to gas , without going into liquid phase.

Fastness to sublimation is probably the most important requirement of dyed polyester, apart from fastness to light. The migration behavior and wet fastness of disperse dyes on polyester are closely involved with their response to heat treatments.

Adequate fastness to heat is essential so that the dyed material will withstand the conditions encountered in

1. Heat setting,
2. Durable pleating
3. Ironing or pressing of the goods during the making-up of garments.
4. Finishing processes where high temperature is involved.
5. Thermal fixation of prints.

The poor sublimation fastness results into following problems

1.Change in original shade
2.Staining on adjacent fibers in contrast dyed fabrics.
3.Poor color yield and fixation rate in thermal fixation of prints.
4.Staining of dyed polyester sewing threads after stitching and embroidery in contrast stitched and embroidered articles.
5.Cross staining during storage.

How to avoid the problem due to poor sublimation fastness

Since the problem of poor sublimation is concerned to polarity of substation groups in dye molecule , therefore following steps are suggested to avoid the problem,

1.Pre heat setting most of the fabrics before dyeing.
2.Carefully selecting the dyes so that all component yarns have satisfactory fastness in multicolored/contrast color designs ,where fabric is post heat set.
3.Selecting high sublimation dyes for dark shades , and medium /low sublimation dyes for pale shades.
4.The sublimation fastness influenced by the dyeing conditions and dyeing cycle followed, therefore the dyeing cycles must be optimized for best sublimation fastness.

How to test the sublimation fastness of disperse dyes

The sublimation fastness of disperse dyes is usually tested for staining and shade change , tested at 180 oC /210 oC for 30 seconds and rating is done on 1-5 grey scales.

Standard Test Method for Sublimation fastness testing.
AATCC Test Method 117-2004
ISO 105-P01.

Color Fastness to Light ( Tests ISO-B01 - B08)

2010-03-25T00:43:00.000-07:00

The purpose of this test is to determine how much the color will fade when exposed to a known light source. The proper test method is AATCC Test Method 16. Option A uses a Carbon Arc light source while Option E uses the more popular Xenon light source. The option used will depend on the equipment available. The test duration will be 10 AATCC fade units minimum for both colors and whites unless otherwise specified. Ten AATCC fade units are the equivalent to 2.5 to 3 continuous twenty four hour days of direct sunlight while 20 AATCC fade units are equivalent to 5-6 days of direct sunlight.

The evaluation will be done as described in the test method with the exception of whites. Whites will be evaluated with the AATCC Gray Scale for Staining because the issue is more often yellowing of the white color.

ISO 105-B01-1999 Textiles - Tests for colour fastness - Part B01: Colour fastness to light: Daylight ISO105-B01 ISO105-B01 ISO105-B01 Read in detail

ISO 105-B02-1999 Textiles - Tests for colour fastness - Part B02: Colour fastness to artificial light: Xenon arc fading lamp test .
for details click here

ISO 105-B03 -1997Textiles; tests for colour fastness; part B03: colour fastness to weathering: outdoor exposure.
for detail click here

ISO 105-B04-1997 Textiles - Tests for colour fastness - Part B04: Colour fastness to artificial weathering.Xenon arc fading lamp test.
For Details Click here

ISO 105-B05-1996 Textiles - Tests for colour fastness - Part B05: Detection and assesment of photochromism .
For details click here

ISO 105-B06-1999 Textiles - Tests for colour fastness - Part B06: Colour fastness and ageing to artificial light at high temperature.
For details click here

ISO 105-B07:2009 specifies a method for determining the resistance of the colour of textiles, of all kinds and in all forms, to the combined effect of wetting with acid or alkaline artificial perspiration solutions and an artificial light source representing natural daylight (D65).

ISO 105-B08:1999 Textiles -- Tests for colour fastness -- Part B08: Quality control of blue wool reference materials 1 to 7 .
For detail click here

A small instrument for testing color fastness
Weather O meter
Definition: The apparatus in which specimen materials can be subjected to artificial and accelerated weathering tests which simulate natural weathering. Controlled cycles of ultraviolet radiation, light, salt, electric arcs, water spray, and heating elements are used to simulate the natural conditions of sun, rain and temperature changes.

Color Matching in Textiles

2010-02-12T04:02:00.000-08:00

Colour is one of the most fundamental aspects of textile design which contributes greatly to the overall visual effect of a finished fabric. Colour matching is a vital process in ensuring continuity of colour from the master standard to all subsequent production batches.
A variety of conditions affect how a color looks
1.Light- source difference
2.Observer Difference
3.Size Difference
4.Background Difference
5.Directional difference
How to Ensure Effective Color in Today's Manufacturing Processes?

The three components of colour matching

There are three components involved in colour viewing,which are LIGHT, VISION and OBJECT. If any omponent changes, the actual perception of colour will also change.
It is important to keep the conditions (as mentioned above) constant when viewing colors.

Colour matching requires the use of a standard light box which has several illuminants:-

Some of the standard light sources

Artificial Daylight D65, Why Daylight?

A - tungstun
CWF - Cool White Fluorescent
TL84,
UV,
U30

Learn about Various Light Sources
Importance of color Management

Color Rendering of Light Sources

Everybody's perception of colour is slightly different. Light boxes are therefore employed so that whenever samples are viewed the conditions are exactly the same.
Color Viewing booth / light box for color matching.

It's difficult to see the true color under different light sources in which measurement color deviation intends to occur when performing the color evaluation without a standard light sources. To simulate different light sources to obtain an objective color, color difference and color evaluation, we can put the test specimen into the color viewing booth / color light box, so that it's easily to see the true color daytime, night, indoor and outdoor, and ensure the color consistency.
The Problem of Metamerism
Metamerism in textile shade matching is defined as a phenomenon in which two colored objects appear same in one light source but differ when the light source is changed. This could be due to difference in pigments or materials.
The spectral reflectance characteristics of the colors of two objects are different , but the resulting tristimulus values are same in under one light source but different in another.
Color Measurement Methods for Textile Fabrics
Color Tolerances for Consistent Pass/Fail Decisions

Colour Space
What is a color model?

Every colour has a colour space which can be pinpointed by coordinates given by a computer. Colour can also be checked by eye and given a colour space, but again this is open to subjectivity.

The three fundamental aspects of colour are lightness, chroma and hue.

Lightness( bright colors,dark colors,light colors, the lightness of color changes vertically) is shown on the "L" axis. It indicates the depth of a colour, ranging from white to black with grey in between. One way of picturing depth of colour would be to imagine a black and white photograph where every colour is shown as a different depth of black, white or grey. The lightness of the fabric sample would be represented by a number on the "L" axis.

Chroma or saturation ( Vivid colors, dull colors, chroma changes outward from the center) is shown as the distance away from the "L" axis.

If the colour is described as being at the very outside edge of chroma it will appear to the observer to be very clean and bright. As it moves towards the grey central "L" axis it will become greyer, flatter and more dirty.

Hue (Redder, greener, yellower, bluer etc. hues form the color wheel) is the variation in colour. For example, a blue may be very red - moving towards purple lilac - and would appear in the blue colour space at the red side. Different shades of blue would all appear in the blue colour space but in different areas.

Lightness, chroma and hue are checked on all yarns and piece dyed fabrics to ensure colour continuity standards are maintained to the highest levels. They can be represented as a three dimensional figure.

More Information on Color Theory

A Note on Color Inconstancy
Read Book on Color Space conversions
CIE color model

Complementary colors
Electromagnetic energy
Desaturation
Gamut
Grayscale
HSV color model
Hue
Light primary colors
Print primary colors
Saturation
Secondary colors

Background knowledge of different light sources
CIE Fluorescent Illuminants
Artificial Daylight D65 which corresponds to a mid-day sun in Western Europe / Northern Europe is a commonly-used standard illuminant defined by the CIE. It is part of the D series of illuminants that try to portray standard illumination conditions at open-air in different parts of the world. Artificial Daylight D65 light sources do not exist actually, only simulators. The quality of a simulator can be assessed with the CIE Metamerism Index. —CIE S005/E-1998.

TL84 - CIE Fluorescent Illuminants, Light Source (F11), TL84 light sources represent a tri-band fluorescent lamp. —CIE 1931.

CWF - CIE Fluorescent Illuminants, Light Source (F2), CIE F series light sources represent various types of fluorescent lighting. CWF(Cool White Fluorescent) light sources found in office environments.

Incandescent A - CIE Incandescent A is intended to represent typical, domestic, tungsten-filament lighting. Its relative spectral power distribution is that of a Planckian radiator at a temperature of approximately 2856 K. CIE standard Incandescent A should be used in all applications of colorimetry involving the use of incandescent lighting, unless there are specific reasons for using a different illuminant. It is found in our home.

UV - UV Ultra Violet Black light to reveal the presence of fluorescent dyes and bleaches.

U30/U35 - Neutral-white fluorescents have a CCT (Correlated color temperature) of 3000K or 3500K.

Fabric Dyeing Machines

2010-02-08T03:51:00.000-08:00

Open width dyeing Machines
Batch dyeing
Batchwise dyeing of woven cellulose fabrics
Semicontinuous dyeing
Continuous Dyeing
A Project Report on Continuous Dyeing
Rope Dyeing Machines
Watch Videos:-
Fabric Dyeing-1
Fabric Dyeing-2
Multiflux HT Fabric Dyeing machine
Fabric dyeing
Rapid and efficient dyeing: A literature survey with emphasis on jet dyeing, 1970-78 (Shirley Institute publication)
Cotton Dyeing and Finishing : A Technical Guide
Chemistry for Textile Students; A Manual Suitable for Technical Students in the Textile and Dyeing Industries

Color Fastness To Vuclanizing and phenolic Yellowing

2010-02-06T00:29:00.000-08:00

Click The links below for Details
Color Fastness To Vuclanizing Hot Air
Color Fastness To Vuclanizing :-Sulphur Monochloride
Color Fastness to Vulcanizing ;- Open Steam
Phenolic Yellowing ,
New Testing Standard :-
ISO 105-X18:2007 specifies a method intended for assessment of the potential to phenolic yellowing of textile materials.
The method is specific to phenolic yellowing and does not cover the many other possible causes of yellow discolouration found on textile materials.

Textile Testing and Analysis
Issues In The Analysis And Testing Of Textile Composites With Large Representative Volume Elements
Applied basic textiles;: Raw material, construction, color, and finish, fabric analysis, chemical and physical testing of textiles, spot and stain removal, and care of clothing,

Mercerizing Of Knit fabrics

2010-02-02T04:04:00.000-08:00

Tubular Knit Fabric Mercerising

The available mercerising machines are not suitable for knit fabrics due to following reasons,

Difference in constructional features of the fabrc.
Sensitivity towards the tension and stretch applications.
The unsuitability of usual woven cloth expanders for knitted fabrics.

Main sections of a Tubular Knit Merceriser are

Special entrance scaffolding suitable for knit fabrics with guide rollers
Impregnation compartment
Ring Expanders
Dimensional stability section
Fabric Straightening Section
Washing Section

Swastik Merceriser for Tubular Knit Fabrics For details click Here

Patchy dyeing in Mercerised Knit Fabrics :-Analysis and Corrective action

Open Width mercerizing of Knitwear :- A Study

Knitwear open concepts Knitline
Singeing Machine for Knits EcoSinge®
Machine for Knit Mercerising EcoMerc® and EcoCombine® EcoMerce
Finishing of woven and knitted fabrics with elastane fibers Read Here
Menzel continuous merceriser
Mercerising system is to small and medium production volumes Menzel Minimerce

Fabric Mercerising Process

2010-02-02T01:58:00.000-08:00

Mercerization, the treatment of cotton with a strong caustic alkaline solution in order to improve the luster, hand and other properties,was names after its discoverer, John Mercer.

Mercerization leads to a number of changes in fibre and fabric properties:

• a more circular fibre cross-section
• increased lustre
• increased tensile strength, a major factor for technical textile fabrics
• increased apparent colour depth after dyeing
• improved dyeability of immature cotton (greater uniformity of appearance)
• increase in fibre moisture regain
• increase in water sorption
• improved dimensional stability.

Types of mercerization

Mercerization is widely used, and in the mercerization of different kinds of cellulose products, including blended products, the machine used and the treatment conditions must be selected in accordance with the type of fiber, the form that it is in and its properties, and also in accordance with the aims and the timing of the mercerization.

The wide range of treatment methods can approximately be broken down into the following divisions. Parentheses denote established terminology.

1. Classification according to the form of the product

a) Yarn mercerization

Batch : Hank mercerization
Cheese mercerization
Continuous : Single end mercerization
Tow mercerization
Warp mercerization

b) Knit Mercerization

Open mercerization
Closed mercerization (Round mercerization, tubular knit mercerization)

c) Cloth mercerization

Chainless mercerization (Roller mercerization)
Chain mercerization (Stenter mercerization)
Batch-up mercerization

2. Classification according to the marcerizing conditions

a) Water content

Dry mercerization
Wet mercerization

b) Tension

Fixed-length mercerization
Tension mercerization
Tensionless mercerization

c) Alkaline concentration

Low-concentration alkaline mercerization
High-concentration alkaline mercerization
Two-step mercerization

d) Temperature

Ambient-temperature mercerization
High-temperature mercerization
Low-temperature mercerization

3. Classification according to timing

Gray mercerization
Pre-dyeing mercerization
Post-dyeing mercerization

4. Classification according to the number of treatments

Single mercerization
Double mercerization

5. Classification according to the type of alkali used

a. Caustic soda mercerization

b. Ammonia mercerization

Liquid ammonia treatment is a highly effective and well-controlled alternative to caustic soda mercerisation, but the high capital cost of the necessary equipment for recovery and reuse of the ammonia as well as the application step limits the adoption of this sophisticated approach more widely. The effect of liquid ammonia treatment on the dyeing of cotton depends on the way that the ammonia is removed. Aqueous washing gives a product almost as dyeable as mercerised cotton. As with mercerising, treated yarns and fabrics appear more deeply dyed than untreated material having the same amount of dye present

6. Other

a. Alkali pad-dry method
b. Alkali pad-steam method

While other variations are also used, mercerization in industry is generally implemented according to a combination of the basic factors as listed above.

Fabric Mercerising Machine
Chain Mercerizing Machines

In order to make up for the shortcomings of the roller mercerizing machine, a clip stenter is used for post-mercerization treatment, in which a widthwise tension is applied then most alkali is showered off the fabric kept on the stenter, followed by thorough alkali removal and neutralization using an open-width washing machine.

Chainless Mercerising Process

This method of mercerization running fabric through a number of rollers without the use of a clip stenter is also called roller mercerization. The machine used has a number of stainless rollers, or stainless and rubber rollers, of a relatively-large diameter tiered zigzag in close contact to each other inside a long trough, with the lower tier designed to submerge in alkaline solution for mercerization.

Cotton Fabric and Yarn mercerising process
What is mercerized cotton?
Mercerization Process Produces Quality Fabrics

Hot Mercerization
Main steps in hot mercerising process are
1. Saturation with mercerising-strength caustic soda solution at a temperature close to its boiling point
2. Controlled hot stretching for a brief dwell period
3. Controlled cooling and dilution of the caustic liquor
4. Traditional tension-controlled washing and final rinsing.
Advantages of Hot Mercerising
The main chemical and physical changes to achieve the desired improvement in fabric properties do not take place at the high temperature of the saturator but when the cooling fabric passes through the traditional caustic dilution and washing-off stages.
1. Shortening of the process sequence to provide cost savings

2. Increased efficiency and reproducibility
3. Use of chain or chainless mercerisers with fewer problems related to fabric width control
4. Improved lustre, tensile strength and dimensional stability because greater stretching of the fabric is practicable
5. Increased dye uptake at moderate tension, but excessive stretching can result in lower dyeability
6. Improved results from fabric qualities containing lower-grade cotton
7. Flash scouring effect obtained
8. Good desizing action
9. Enhanced penetration of the fibre by the hot caustic liquor.

Study of some important parameters of greig cotton after Hot mercerization
Effect of heat on mercerization
An Investigation on the Effect of Hot Mercerization on Cotton Fabrics Made up of Open-End Yarns
Effect of mercerization treatment on dimensional stability of weft knitted fabrics

Foam Mercerizing

Mercerizing strength sodium hydroxide may be foamed and this foam applied to cotton by conventional methods. Application of foamed sodium hydroxide offers the possible advantages of savings in sodium hydroxide and dyes as well as ability to treat selectively given areas of the fabric. This technology may be useful in areas other than mercerization.

The following advantages has been claimed by the experts in this area are,

1.No specialized machinery is required.

2.Less consumtion of alkali.

3.Better control of fabric dimensions

4.Preferential treatment of one face of fabric when needed.

5.Penetration of lye in pile fabrics with less lye.

6.Possibility of printing with sodium hydroxde.
7.Possibility of better coverage of dead cotton and resulting into uniform dyeing.

Slack Mercerizing :-Loose mercerizing or mercerizing without tension
Slack mercerizing is done by exhaust. The fabric is slacked and treated with NaOH solution by this process of mercerizing no luster is obtained but absorption is increased.
Slack mercerization is different than normal mercerizimg that it must be planned in advance and will result into a stretch fabric. Fabric to be slack mercerized is woven with enough space left between the yarns to crimp up knowing it will be slack mercerized. Once the fabric is slack mercerized it will become tighter and narrower while at the same time giving a permanently crimp that makes for 100% stretch cotton. It’s like giving hair a perm. It is possible to get up to 15% comfort stretch and in a twill utility stretch.

Technology highlights of Goller Mercerizing Machine

Watch video of knit mercerizing here

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