Fabric Dyeing Tips and Tricks

Stripping and Shade correction of dyed materials

2008-11-13T18:37:00.002+05:30

There are possible occasions arise for the correction of the dyed shade. According the substrate(fabric/yarn)
quality and the dyestuff used for dyeing, the following methods may be considered useful:

A) Cellulose:

1) Direct dyes are best removed by an alkaline reduction strip. Some
dyestuffs may require a non-ionic boil off.

2) Vat dyes are very difficult to remove, usually a strong reduction strip
with caustic and hydros and strong organic stripping agent (leveling/dispersing agents).
are required. Mostly the treatment has to be done at 80°C or more.

3) Sulfur dyes can be removed partially in depth by treating the fabric
with sodium sulfide at 80°C or with caustic and hydros. You can make a judicial
combination of 2 treatments to strip off maximum color by treating the
fabric with sodium hypochlorite 3 to 5 g/l followed by a reduction strip
with caustic and hydros.

4) Naphthols: Either oxidizing agents (hypo) or reducing agent would
work as stripping agents. But case to case this would defer. Lab trial
is essential before finalizing anything on bulk treatment.

5) Reactive: Either hypochlorite or hydros or caustic hydros would
work. Before doing bulk stripping one has to test the suitability. Most
2 treatments are required. Hypo treatment followed by caustic hydros or
Caustic hydros treatment followed by hypo treatment would work.

B) Polyamide (nylon) stripping:

A reduction stripping in alkaline medium with a non-ionic dispresing agent
yields better result.

Light shades may be stripped by a mild boil off in the presence of
a non-ionic dispersing agent.

Deep shades and pre-metalized dyes may be stripped by an oxidizing
bleach with sodium chlorite in acid medium.

C) Polyester:

Disperse dyes may be stripped by boiling off with a suitable carrier
and dispersing agent.

Azo type disperse dyes may be stripped off by reduction method (caustic
and hydros).

FABRICS FROM RICE STRAW AND CHICKEN FEATHERS

2008-06-11T14:19:00.002+05:30

Organic Fabrics

After organic food and Fair Trade cosmetics comes "sustainable" fashion. Scientists are investigating natural sources for biodegradable artificial fabrics made from raw material such as chicken feathers and rice straw.

As Katharine Hamnett, the iconic 1980s designer, prepares for the launch in spring of her organic, environmentally friendly fashion range, the idea of ethically sourced sustainable fashion is starting to take hold. Ham-nett's online store, which she has sold her pounds 1m house in Highgate, north London, to launch, features designs made in cotton grown organically without pesticides.

The production process spares the thousands of farmers who she says commit suicide after falling into debt to the pesticide companies or whose health is damaged by the chemicals. "I'm not prepared to make a living at the expense of those at the bottom of the supplychain," Hamnett said. "I want to prove it can be done so there are no more excuses."

Scientists at the University of Nebraska plan to go one stage further by developing fabrics from agricultural waste products to replace synthetic materials derived from byproducts of petroleum. In place of nylon and acrylic we could see "chicken wool" and "rice cotton". Millions of tons of chicken feathers and rice straw (the stem of the plant left after the grains are harvested) are discarded every year.

Research presented to the American Chemical Society conference in San Francisco yesterday shows that fabrics made from them could become an abundant, cheap and renewable alternative to nylon and acrylic.

The chicken feather fabric will resemble wool and the rice straw fabric will be similar to cotton or linen. Fibres derived from chicken feathers would be an improvement over wool, the researchers say.

Rice straw, composed of cellulose, has already been made into fibres, which could be spun into fabrics similar to cotton or linen using common textile machinery.

Both fabrics are still in the early stages of development but the researchers say they could be a boon to rice and chicken farmers as well as being kind to the environment. Yiqi Yang, professor of textile science at Nebraska University, who led the research, said: "We hope the research presented here will stimulate interest in using agricultural byproducts as textile fibres which would add value to agricultural crops and make the fibre industry more sustainable."

No major effort is currently being made to find alternative sources of fibres to satisfy increasing global demand. Two years ago Professor Yang and colleagues developed a method to turn corn husks into fabrics but those based on feathers and straw could have better properties, they say, suitable for use in carpets, cars and buildings. They would cost less and have superior properties to their synthetic counterparts, the researchers say.

Laundry Care Guide for all fibers

2008-04-18T13:15:00.006+05:30

These fabric care suggestions are provided as a general guide for the benefit of our visitors. Because materials and dyes vary between manufacturers and products, for best results we recommend that you test a sample before washing or dry cleaning the entire garment.
Acetate: Dry clean only.

Acrylic: Machine wash warm using warm water, softener may be added during the final rinse cycle. Machine dry using low temperature, remove promptly when done.

Cotton: Machine wash warm, tumble dry low. Use cool iron.

Metallic Cotton: Machine wash warm, delicate cycle, tumble dry low,. Cool iron may be used.

Fleece: Machine wash warm and remove quickly to avoid matting. Hang to dry; do not use dryer.

Linen: Dry clean is recommended and retains the original crisp finish to the fabric. Hand wash in mild soap no chlorine bleach dry by laying flat on clean non-colored towel. Note: Hand washing softens the feel of the linen which is sometimes preferred.

Lyocell: Lyocell garments may be either machine washable and dryable or drycleanable. Read the label. Washable lyocell has the strength and ease of care of other easy-care fabrics. Machine wash and dry at low temperature. Remove from dryer as soon as the garment is dry. If ironing is required, use a moderately warm iron.

Lycra: Hand or machine wash in lukewarm water. Never use chlorine bleach onany fabric containing Lycra. Either drip dry or machine dry using lowtemperature settings.

Lycra Velvet: Hand or machine wash in lukewarm water. Never use chlorine bleach on any fabric containing Lycra. Either drip dry or machine dry using low temperature settings.

Microfibers: Acrylic, nylon and polyester microfibers are machine washable, machine dryable or drycleanable Follow the instructions for washing fabrics consisting of these individual fibers.

Nylon: Most items made from nylon can be machined washed and tumbled dried at low temperatures. Use warm water and add a fabric softener to the final rinse cycle. To minimize static electricity use a dyer sheet when machine drying. Remove articles from the dyer as soon as the tumbling cycle is completed. If ironing is required, use a warm iron.

Polyester: Use warm water add fabric softener to final rinse, machine dry low and remove promptly from dryer. If ironing is needed use a moderate warm setting. All polyesters can be dry cleaned.

Polyolefin: Most items can be washed or dry-cleaned. Most stains can be readily be removed by wiping, using lukewarm water and detergent. If fabric is machine washed, it should be line dried or tumbled dried with gentle or no heat. Do not iron.

Rayon: Dry cleaning is recommended. Although hand wash in lukewarm water is okay. No chlorine bleach allowed. Lay flat on a clean non-colored towel to dry.

Silk: Dry cleaning is preferred. Hand washing is possible if mild soap and lukewarm water is used. Laying flat on a clean non-colored towel to dry.

Spandex: Hand or machine wash in lukewarm water. Never use chlorine bleach on any fabric containing Lycra. Either drip dry or machine dry using low temperature settings.

Suede: Recommendation is dry cleaning. Although Machine wash gentile cycle is allowed.

Triacetate: Pleated garments are best hand laundered. Most other garments containing 100% triacetate can be machine washed. If ironing is needed, a high temperature setting may be used. Articles containing triacetate require little care due mainly to the fiber's resistance to high temperature.

Woodblocks: As with all hand-printed fabrics, we suggest you do the following: prewash by hand with mild detergent and rinse until water runs clear. Dry flat. Additional color transfer from dark to lights may occur when sewn and washed together. We suggest you take this into account when designing your projects. We hope you enjoy the results when you use this ancient fabric handicraft.

Wool & Suiting: Recommendation is for dry cleaning. Can be spot cleaned with a damp sponge.

Perfection via Imperfection

2008-03-15T12:53:00.004+05:30

I want 100% lab to bulk reproducibility. I have the following facilities:

For cost saving and matching price requirement of the buyer, I will buy only the optimum quality of yarn or fabric.

Enzyme desizing is a costly operation. I used to do either acid desizing (which I consider it as two in one operation, i.e., desizing and deminaralization) or no desizing.

I will buy only the best priced auxilary and basic chemicals to save cost. If I can get better price from somebody, I will switch over to the new supplier.

Of course the machineries were purchased 10 years before. I know that there are some leakages here and there. What if? This is the case with every body in the field.

I am getting abundant water from out side wells. More that 10 wells are in my list. If there is a crowd in one well, then the lorry driver will go to the next one and supply water at any cost. Of course I know that there will be some small variations of 100 to 200 ppm hardness and TDS variations between wells.

I have increased the number of machineries by about 10% last year. The boiler is so efficient and supplies steam. Only at times, we could reach a boiling temperature for scouring or soaping. But we are managing however.

The new dyeing master is not so good and he takes about 20 to 24 hours for completing each batch. He could not take even a single batch without making additions in dyeing or sometimes redyeing. If you know somebody, please help me. I want a man who can take dyeing 100% lab to bulk exact???????

Free Blog Links

2008-03-10T16:42:00.000+05:30

Free Blog Links

Disappearing Redder Tone after Enzymatic Biopolishing

2008-02-29T06:41:00.005+05:30

It's something mysterious. They are using a good dyestuff (RGB's) for dyeing a medium olive green shade. The combination Yellow, Red and Blue RGB, where red is a very small per centage, but a toner to reach that particular shade.

They have dyed the shade and reached the tone and depth. Soaped throughly and after soaping they have collected the sample and found still matching to the shade.

To their surprise, after bio-polishing with a standard enzyme, they found that the red has substantially gone out and the shade was off.

Can any one suggest, what may be the reason for this tonal change?

Privacy Policy

2008-02-27T15:45:00.002+05:30

Privacy Policy Statement

I am S.Baba Partheban

fabric-dyeing.blogspot.com is my blog, created with a view to share my experience and knowledge with people related to this industry. Wherever sources from other references were cited, due links to original source data have been mentioned with thanks.

My postal address is - 10 Ramanujam Nagar, Karur -639002, Tamilnadu, India and anybody can contact me regarding this blog thru my e-mail id thesmarttime@yahoo.co.in and you will be properly answered.

The content of this site, is written from my own experience in this field of textile processing.

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Soft Flow Dyeing Mystery

2008-01-30T11:01:00.001+05:30

In Tubular knit dyeing machine - soft flow - yesterday a dyeing master showed me a fabric roll dyed in medium depth navy blue shade. They have used Dystar RGB type of dyestuffs. To my surprise, exactly 1/2 of the tube appears slightly yellower and the other side appeared to be redder and bluer, throughout the length of the piece. They asked me what would be reason for this type of peculiar behavior? I just gave some of my suggestions and I would like you to share your experience with me.

Since the fabric is a double jersey type of one, due to heaviness of the fabric there is a possibility of one side of it getting abraded against the stainless steel parts of the high pressure of the nozzle. I suggested them (a) to increase the size of the nozzle, if possible; (b) increase the quantity of lubricant they are adding; (c) avoid using caustic soda in the dye bath.

Note: The fabric is not a mercerized one and it is open air dried one and not dried in the relax dryer.

Please comment on this please.

New Concentrated Dyestuffs in Fiber Reactive Dyes

2007-11-29T07:41:00.000+05:30

Concentrated Reactive Dyes:
In order to reduce the cost of dyeing and improve the fastness properties, almost all dyestuff manufacturers have introduced the above dyes as economical and eco friendly series.

These are either bifinctional or multifucntional type of reactive dyes.

Every manufacturer gives a special name and suffix that denotes the concentration, economy and eco-friendliness.

DE, EC, SP, Supra, HF are some of the well known suffixes.

What are the properties of multifunctional dyes?

There are dyes that have more than one chromophore - coloring matter and more than one auxo-chrome - the linking or reactive part.

The multifunctional dyes have special tones and shades that were usually dyed using two are more dyestuff combinations. For example a bright scarlet dyestuff is available in this class. Usually a scarlet shade is dyed with a combination of a red and orange or red and yellow. Similarly multi auxochromes yields very high wash fastness due to the strong multi faceted bonding of the dyestuff molecule with fiber.

Since these multifunctional dyes have more reactive groups, the exhuation and fixation rates will be higher than conventional bifunctional dyes, resulting in better utilization of dyestuff and lower pollution load to effluent.

Mercerisation - Adds Strength and Lusture to cotton fibre !

2007-11-26T18:44:00.000+05:30

What is Mercerisation? What are the benefits of mercerising? What is the Technique of mercerising?

You find answer to all your questions here!
Chemical treatment applied to cotton fibres or fabrics to make them permanently able to accept dyes and various chemical finishes more easily. The method, patented in 1850 by the English calico printer John Mercer, also gives cotton cloth increased tensile strength and greater absorptive properties. Higher-quality cotton goods are usually mercerized. The treatment consists of dipping the yarn or fibre in a solution of sodium hydroxide and then treating the material with water or acid to neutralize the sodium hydroxide.
One of the most important treatments performed on cellulosic fibres to improve properties such as dimensional stability, tensile strength and lustre, is mercerisation. The aim of this work was to study the crystallinity, accessibility and unit cell structure changes occurring in three types of regenerated cellulose fibres (lyocell, modal and viscose) that were mercerised with caustic soda solutions of different concentrations. Differences were observed between the behavior of the viscose type fibres (viscose and modal) and that of the lyocell fibres. For the viscose type fibres, the proportion of crystalline regions increased at low alkali concentrations, while for lyocell fibres a decrease in crystallinity was observed. In all three fibres there was a transformation from cellulose II to amorphous cellulose. While for lyocell the transformation was partial, the modal and in particular the viscose fibres showed a complete transformation, and the swelling agent caused the fibre to dissolve at high caustic concentrations.

Mercerising
Mercerising is carried out in order to improve tensile strength, dimensional stability and lustre of cotton. Moreover an improvement in dye uptake is obtained (a reduction of 30 - 50 % of dyestuff consumption can be achieved thanks to the increased level of exhaustion).
Mercerising can be carried out on yarn in hanks, woven and knitted fabric through one of the following different treatments:
· mercerising with tension
· caustification (without tension)
· ammonia mercerising.
Mercerising with tension
Caustic soda mercerising is the most commonly applied mercerising technique (it is not applied to flax). Cotton is treated under tension in a solution of concentrated caustic soda (270 - 300g NaOH/l, which means also 170 - 350 g NaOH/kg) for approximately 40 - 50 seconds.
During mercerising the temperature is adjusted at low values (5 - 18 °C) when the lustre is the priority and at slightly higher levels when the improvement of the other characteristics is preferred. Because the reaction between caustic soda and cellulose is exothermic, cooling systems are applied to keep down the temperature of the bath.
Beside the conventional cold treatment, a hot mercerising process is also now increasingly applied (for hanks and fabric). The material is soaked in a solution of caustic soda close to boiling point. After hot stretching, the fabric is cooled down to ambient temperature and washed under tension.
In order to ensure a homogeneous penetration of the liquor, especially when operating at ambient temperature, wetting agents are employed. Sulphonates mixed with non-ionic surfactants and phosphoric esters are the most commonly used.
Caustification
In the caustification process, the material is treated at 20 - 30 °C with caustic soda at lower concentration (145 - 190 g/l) without applying tension. The material is allowed to shrink, thus improving the dye absorption.
Ammonia mercerising
Cotton yarn and fabric can be treated with anhydrous liquid ammonia as an alternative to caustic soda. Effects similar to mercerising are obtained, although the lustre grade is inferior to caustic soda mercerising. Traces of ammonia have to be removed, preferably with dry heat treatment followed by steaming.
Read more at TheSmartTime.com

Influence of pH in Reactive Dyeing

2007-11-26T17:30:00.000+05:30

Influence of pH in Reactive Dyeing:
Let us discuss about the general quality of all reactive classes now in the market.
All reactive dyestuffs are very much sensitive to the concentrations of alkali and pH in turn. The cleavage of one or two chloride ions from the dyestuff molecule and the reaction of the rest of the dyestuff molecule with the secondary hydroxyl group of cellulose, producing a strong covalent bonding is the essence of reactive dyeing in total.
But how much alkali and how much pH is required for each class of reactive dyestuff depend on the reactivity of the dyestuff itself.
M BRAND DYES are highly reactive requiring comparatively milder conditions in dye fixation. They are primarily of interest in dyeing at normal room temperature (about 25º - 30º Deg. C) using Soda Ash or Sodium Bicarbonate. M BRAND dyes are applicable to cellulosic textiles by Batch-wise, Semi-continuous and Continuous methods in conventional textile machinery like open-vat, Package, Jet, Jig, Winch and padding mangle. The versatility in various application procedures and the availability of wide range of bright and fast shades are the outstanding features of this class of dyestuffs.

Due to the very high reactivity of this class of dyestuff, they require lesser amount of alkali for fixation. A pH of 9.3 to 9.8 will be sufficient for proper fixation of the dye to cellulose.

Read more in TheSmartTime.com

Hints on the Right Method of making Tonal Corrections During Bulk Dyeing

2007-11-26T17:17:00.000+05:30

Right way of making tonal corrections:

The Examples are made with respect to Reactive Dyeing:
It is almost imperative to make small changes in the final tone/depth of the shade to meet the requirement of the customer.
Every dyer has his own way of making the dyestuff additions and we recommend the following few safe methods.
Some important factors to be considered before making additions.
How much addition will be necessary to reach the shade?

Arrive at a recipe in terms of % of original recipe.
Let us consider that a 5% shade is running on the machine. You assess that a 20% extra dyestuff is required.

How do you add this dyestuff?
As usual dissolve the dyestuff, filter it and make it ready for addition.
Now consider that a 20% of 5% original depth is only 5 x 20/100 = 1%.
In the dye bath you have been using for dyeing a depth of 5%, the salt and soda present are two high for a mere1% additional quantity of dyestuff.
This very high concentration at the fixation temperature of 60° or 80°C will easily hydrolyze the 1% dyestuff you are adding. You will not get the required change in shade.
Then what you should do?
Now you require only 1/5 of the original concentration of salt and soda and you should protect the fabric from direct strike off of the dyestuff at the fixation temperature to avoid uneven dyeing.

What you should do?
Drain off 70 to 80% of bath, add fresh water, if necessary add the required amount of some good sequestering agent. Now check the temperature. It will be almost 40°C.
Now you inject the additional dyestuff slowly in to the machine.
Run at that temperature for about 1/2 hour. Check the sample. If the tone and depth are ok. Run for another 10 minutes at the same temperature and drain the bath.
If after 1/2 hour the tone and depth are still lighter, increase the temperature to the required level and check for tone and depth.

What will happen if straightaway the required dyestuff is added in to the same bath without taking all the above precautions?
Unevenness is 60 to 80% possible.
Poor rubbing and washing fastness will result.
Sometimes the depth or tonal changes, will not at all occur due to premature hydrolysation of the additions made to the bath.

No Soap Reactive Dyeing

2007-11-26T16:50:00.000+05:30

Question: Is soaping necessary after Reactive dyeing of cellulosic materials? Or Why soaping is essential after dyeing?

Answer: Omitting the use of detergents in after washing of cotton dyed with reactive dyes :

Description: Both international literature and practical experience in textile mills show that detergents do not improve removal of hydrolysed reactive dyestuffs from the fabric.On the contrary, high temperatures do have an affect on rinsing effectiveness. Tests carried out with rinsing at 90 - 95 °C have shown that rinsing is more effective and faster at high temperatures. About 30 % more unfixed hydrolysed reactive dyestuff is rinsed out after 10 minutes of rinsing at 95 °C than at 75 °C.Many dye houses already carry out hot rinsing and omit the use of detergents in rinsing after reactive dyeing. The product quality is not negatively affected. On the contrary, most often the fastness of the goods are better after the hot rinsing than after the traditional rinsing with detergents, complexing agents and neutralisation in the first rinse.Energy should be recovered when using large volumes of hot process water. Energy reclamation can be done either by heat exchange between the hot outgoing process water and the cold incoming clean water or by reclamation of the hot water and re-use of both energy and water.

Read more at TheSmartTime.com

Batch to Batch Shade variation in Dyeing

2007-11-26T16:37:00.000+05:30

Question: I am getting batch-to-batch variation for the same reactive shade, in Soft Flow machine. I am using the same manufacturer’s dyes and chemicals and almost same quality of fabric. What are the reasons and how to avoid it?

Answer: Batch to batch shade variation is a general phenomena noticed almost everywhere in dye houses. There are so many factors that affect a particular dyeing operation. Please make the following checks; I hope you can eliminate 90 to 100% of the above problem.
Phase-1: Preparatory Stage.
Check the batch weight exactly for all batches. Find the exact GSM of the greige fabric and note down on your job card.
After Scouring, Bleaching and neutralization, before dyeing, take a sample, dry it, condition it and check the GSM.
Note down the difference in percentage as Scouring and bleaching loss on the job card. Compare this loss% between each batch. It should not deviate more than 2 to 3%.

Read more detailed discussion in TheSmartTime.com

Textile Waste Water Treatment - Novel Method

2007-09-17T12:31:00.000+05:30

Now in India and all over world the environmental awareness becomes very high among people. The government and the international authorities like WHO, WTO etc has started following strong measures in the implementation of pollution control measures where ever possible.

Now the Indian Government has issued notice to all dyeing units and textile processing industries to implement a Zero Discharge of Effluent on the ground system.

Although it seemed to be not a practical thing from the point of view of the business man doing processing, but it is a must to save the precious water.

The cost of treatment of water seemed is very high and it is in the order of Re 0.50 to 1.0 per litre, if zero discharge system is to be adopted.

So many research and development is going on, in pre and post Reverse Osmosis treatment of waste water.

For one such pre R.O. treatment please visit thesmarttime.com

Textile Testing Methods - Free of cost

2007-09-03T16:31:00.000+05:30

We have included and still including Testing Methods for all textile chemicals, auxiliaries and 'pre' and post finished textile goods.

If anybody wishes to form Quality Control norms for the incoming chemicals, to their dyeing unit, this will be an useful guide for them to follow.

From basic chemical testings to finished goods testings have been slowly incorporated in this section.

Some of the tests I am naming here for your reference;

Hope you will get all your testing requirements!.

Cost and Energy Saving in Reactive Dyeing

2007-09-03T16:13:00.000+05:30

The Pre-Conditioning method of dyeing is an energy efficient way for successful repeat dyeing's of dark and light shades with additional 20 to 30% depth yield in dyeing. Apart from depth you will get improved washing and rubbing fastness properties.

This method is suitable for Vinylsuphone and Bi-functional dyestuffs of Reactive group.

No steam is practically required for dyeing using this method.

This method has been practiced for many years by few people who are still able withstand the market requirements by way of providing good quality dyeing at a cheaper rate.

Brilliant Blue R, Black B, Black GD, Black HFGR, Red BS, Red RB, Yellow RNL, Yellow MERL, Red F3B, Blue BFN are some of the dyestuffs that may be used for this process.

You can have complete detail of processing at thesmarttime.com

Textile Fabric Dyeing

2007-09-03T07:52:00.004+05:30

Welcome to the blog of Textile Fabric Dyeing

This is a collection of data on textile processing right from basic techniques to the latest.

The author S.Baba Parthiban has been in this field for more than 25 years and has made a venture in sharing his experience with the people of the same industry thru this portal.

From environmental pollution to the nano textiles and intelligent textiles, there are so many interesting articles are being updated in this website. Anybody who wishes to share his expertise, or wish to publish some information about his company may approach the author through the website.

thesmarttime.com has already established a regular flow of visitors ranging from 100 to 1000 per day.

Please participate in this endeavour and help the busy techno crates with useful information on knowledge.

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