My Textile Notes

Some Common Synthetic and Blended Fabrics-1

2012-01-28T22:57:00.003+05:30

Here is a list and pictures of some synthetic and blended fabrics

Satin

Satin is a type of glossy fabric.

It is commonly used in apparel : satin baseball jackets, athletic shorts, women's lingerie, nightgowns, blouses and evening gowns, but also in some men's boxer shorts, shirts and neckties.Other uses include interior furnishing fabrics, upholstery, and bed sheets.

Polyester Satin

They are available in the following weights:

GSM: 85, 100, 140, 160, 210, 230

Lycra Satin

A typical fabric has a composition of 97% Polyester with 3% Spandex, with specifications of 50D*75D+40S and with a fabric density of 250*104. Available in widths of 57"/58" with a weight of 90GSM . Also available in 100, 120 and 140 GSM and widths of 42" and 44".

Nylon Satin

It is available in the GSM: 80, 100 with width of 42”, 44”.

You can have a look here at the qualities running in grey fabric, yarns and finished products in Surat.

to be continued

Textile Testing Videos

2012-01-25T08:43:00.000+05:30

Here are some of the videos on Testing of various textile properties. Please click the grey rectangle at the bottom of the video ( on right hand side) to see the total playlist.

In this playlist I have included the following videos:

1. Garment Seam Slippage
2. Fabric Shrinkage
3. Fabric Yarn Count
4. Fabric Abrasion Resistance
5. Fabric Tensile Strength
6. Fabric Tear Strength
7. Fiber Strength Cotton

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How to instantly determine reed and picks per inch

2012-01-22T22:40:00.003+05:30

When checking the fabrics like cotton sheeting, poplin, cambric, voile, lining and mull, it is often required that the reed and picks per inch are determined quickly. One way is to use the pick glass. However, it is inconvenient and taxing to count each and every thread. The other solution is the use of densimeter or lunometer.

Principle of Densimeter

Moire Pattern

The densimeter is based on the principle that when very fine grids are placed one over the other than particular patterns are observed. In this case there are grating lines etched over the artificial glass. The density of grading lines go on increasing from left to right and is marked. When this grating is placed over the fabric, a point in the grating indicates a particular pattern when the density of grating matched with that of fabric. The position of this particular pattern is observed and the value of density is read from the grating.

Usefulness in Textile Testing

Densimeter can be used in atleast three ways

1. To measure the EPI and PPI of threads in the fabric

This works best when the fabric is grey and white. For dark and knitted fabric, the light source should be beneath the surface of the fabric in order to read patterns.

2. To measure the irregularity in the fabric

Presence of broken pattern of interference lines indicate variation in pick counts, differences in yarn count or color faults.

3. For measuring the shrinkage in the fabric

Instead of measuring the shrinkage in the fabric by marking, it is always better to check the number of threads at various position of the sample before and after the washing. This is particularly useful when shrinkage is checked in the made up garments.

How to use it

1.Place the sample on a flat surface. Put the densimeter above it.

2.Rotate the densimeter until a pattern develops as the lines on the densimeter interact with the lines formed by the threads.

3.Depending on how the densimeter is oriented, the "Point" of the pattern will be pointing to a number on either the Lines per Inch scale or the Lines per Centimeter scale. The number on the scale indicates the thread or line count.

Source

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Factors influencing the cost of Processing

2012-01-16T07:29:00.002+05:30

A very good treatment of the topic is given in this article

Powerloom Mechanisms-1

2012-01-12T22:20:00.001+05:30

Some very nice Videos from NCUTE are available on You tube. A few of them are given below:

1. Loose Reed Mechanism

2. Modern Jacquard

3. Terry Pile Mechanism

4. Beat up Mechanism

5. Drop Box Mechanism

6. Positive Tappet Mechanism

7. Worm Wheel Take up Mechanism

8. Mechanism of Counter Shaft

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Bijnor Textile Cluster- Afterthoughts

2012-01-08T23:39:00.000+05:30

Visit to Bijnor cluster was enchanting. Situated on the banks of Ganges, I could see the prosperity of powerloom owners in the villages of Sedha, Nahtor and Chandpur. Equally disturbing is the struggle that handloom weavers are facing in Kiwar. A lot needs to be done to improve the condition of that village.

Khadi is made in the village of Peruwala and the looms are pitlooms as compared to Sedha where frame handlooms are used. It was heartening to see a full-fledged reactive dyeing plant in full operation in Nahtore. Could see fabric from Seersucker to lightweight Denim being made on the powerloom.The houses are still of the older generation, having timber roofs with lots of alcoves and thick walls. Out side it was mustard and Sugarcane fields that greeted us everywhere we went. Fresh Gur was being made in the way and its soft aroma was filling our nostrils. Also elections are round the corner, so saw many congregration and announcements. Good to see conditions of roads in general.

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Getting Bright Red Color in Vat Dyes

2012-01-05T07:18:00.003+05:30

One solution proposed is to mix Brown R and Red 6B.

http://dimachema1.en.made-in-china.com

Brown R chemically has an excellent wash fastness and dry rubbing fastness of 4 and light 6-7. However, its color fastness to rubbing in wet is only 3. Source

Red 6B chemically also has an excellent wash fastness of 4. However its dry rubbing is only 3-4 and wet rubbing is only 3. Source

Thus it is difficult to obtain the good rubbing fastness in this combination of dyes.

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Twist in Silk

2011-12-28T08:48:00.001+05:30

Silk yarn is classified in several ways based on the twist. A some of them are as follows:

Raw Silk

In this the silk is produced by reeling together baves of several cocoons. It has no twist.

Poil Yarn

A silk yarn produced by twisting raw silk. The twist may be slight or exceed 3000 per meter.

Tram Silk

To make a tram yarn, two or more raw silk threads are doubled and twisted slightly. Generally the twist is about 80 to 180 TPM ( Turns per meter)

Crepe

This yarn is made by doubling several raw silk threads and twisting them to very high levels in the range of 2000 to 4000 TPM.

Organzine

This silk yarn is formed by doubling two or more poil yarn and throwing them in a direction opposite to that of the individual yarn. The twist in the poil yarn will be about 700 TPM ‘Z’ and the doubled yarn will have about 950 TPM ‘S’.

http://www.habutextiles.com

Steaming of Twisted Yarn

The twisted yarn has to be subjected to steaming in an autoclave. This process fixes the twist in the thread. Duration of steaming depends upon the depth of layers of threads in the bobbin and twist levels of the thread. Ten minutes is usually sufficient for organza while more highly twisted crepe require considerably more time of about 2 hours.

Spun Silk Production

2011-12-26T07:23:00.002+05:30

Spun Silk takes the following process route:

1. Degumming the silk waste: It is done in degumming vats.
2. Dryers for drying the degumming material.
3. Openers for opening the fibres.
4. Fillers for opening and cleaning the material.
5. Dressing machine is used for combing the materials neps and remove the foreign materials, neps and short fibre and make a lap with average steple length.
6. Spreader : To further make the fibers parallel. Set frames for obtaining sliver.
7. Draw frame is used for making the Sliver with fibres more perfectly paralised, blending also can be done by this machine.
8. Roving machine for making roving (standard of thread with little twist from silver).
9. Ring frame is used for making the spun yarn from roving and insert sufficient twist for strength and wind in a bobbin.
10. Winding & doubling machine are used for two or three fold commercial yarn.
11. Gassing is done for removing the protruding fibres by passing the yarn through the flame at a speed 500-600 mts/min.
12. Reeling to make standard sized hank.
13. Bundling & Balling : First make a bundle and bale for disposal of the material.

The size of spun silk thread is defined in a similar manner to standards used for cotton yarn. For cotton, the term "2/60s"signifies a two-ply yarn consisting of two single strands twisted together, each having a yearn count of 60.

In the case of spun silk the notation has a different meaning. For example, for 60/2 two yearns with a separate yarn count of 120 have been doubled, producing a ply yarn with a new count of 60. (Source)

Spinning of Tussar

Tassar silk waste is degummed by boiling in a pressurised tank with soap and soda for 30 min and treated with sodium sulphite for partial bleaching. However, to remove gummy matter completely, the material is subsequently kept in a soap and soda solution in a large wooden tank for 3-4 days. After degumming the material is fresh water, hydro extracted and subsequently dried in hot air chambers. The degummed tassar waste is then processed through a series of operations which includes opening, filling, dressing or combing, spreading, drawing, gill roving, spinning and gassing. Mill spun tassar yarn in the range of 60-210s (metric count) can be produced. The yarn is then doubled and twisted according to the required specifications.(Source)

Silk Reeling

2011-12-26T07:04:00.000+05:30

Silk Reeling

In general silk reeling is defined as unwinding of silk cocoon. However it is technically defined as the process of finding the right end of the cocoon filament and jointly taking several ends together to reel raw silk. These processes are carried using reeling machines.

Depending on the size of the yarn required to be produced, filament from the cocoons are drawn out simultaneously, compacted and wound on to a reel. For example, if 20 / 22 denier yarn is required, filaments from 8 to 9 cocoons are drawn out simultaneously, compacted and wound.

Silk Reeling broadly has these operations:

a. Catching the correct number of threads to maintain the denier

This is done using a mechanism called Jettebout.

b. Intertwining of threads

This is done using a special mechanism called croissure. Croissure also squeezes most of the water contained in the filament. If the sericin is wet, the threads wound on the reel will stick to each other and defects like hand gum spots result.

c. Distribution of the yarn

This is done using an arrangement called distributor or traverse.

d. Winding of the Yarn

This is done on reels

Quality of Water used in reeling

The water used for silk reeling should be free from impurities as many animal fibres like silk have a decided tendency to fix any substance found in water. Such water alters the appearance of the fibre as its luster becomes dull and matte, thus reducing the quality of the silk.

Reeling of Tusssar

Tassar reeling is not carried out in filature like mulberry cocoons. Mostly it is done in small quantities by the womenfolk of weaver’s family.

Lacing and Skeining

Lacing
In this process the two ends of the silk hank are tied with coloured thread. Lacing is a process in which a thread passing across the hank in such a way so as to devide it into five equal parts. So that the threads are kept in place to ensure that the thread can be unwound easily. For differenciating different denier of silk different coloured threads are used.

Skeining
It is done by twisting the hank several times and folding it upon itself in a number of spirals.

Book Making and Bailing

The skeins are made into neat books of approximately equal weight and dimensions in a bookmaking machine. In each book there are eight skeins in the horizontal row and five in the vertical row.

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FAQ about Silk Manufacturing

2011-12-25T15:42:00.002+05:30

What is Raw Silk as termed commonly

When we talk about raw silk, we generally are talking about mulberry raw silk. It is the compact untwisted and undegummed silk thread that is formed by combining the required number of silk filaments drawn from as many separate cocoons by a special technique called Reeling.

What is Filature Silk

The building in which cocoons are reeled for the production of raw silk is called a filature.It is carried with

sophisticated automatic machines,to ensure production of raw silk of desired qualities. The filature concept is

seen in developed countries where the raw material (cocoons) are of superior quality.

What is the type of Silk used in Indian Villages

However, more than 50 per cent of silk is reeled by a villager using country charka which forms the cottage industry. In the group of natural fibres.

What is the percentage of Silk production of all Textile fibers in the world

Which comprises cotton, wool and silk, production of silk amounts for 0.3 per cent only.

What are the other uses of silk apart from garments and home furnishings

Silk yarn is used as A package material in pencil industry and for making talcum powder puffs. Silk is used as raw material for preparing sound-free gears for making precision machinery. In France 22-24 denier silk is used in tyre manufacturing to have a longer life span than rubber tyres. Parachutes are made from 13-15 denier silk fiber. The silk gut used in surgery for internal suturing is made from silk glands. The silk glands are dissected out and put in warm water and pulled at two ends to yield a fibre of uniform thickness. This protein is auto absorbable and need not be removed after wound healing. Silk grafts have been used successfully to replace cut arteries.

What type of production is more in India- Raw silk or Cotton waste

India is very poor producer of raw silk to meet international standards. In India raw silk production is overtaken by silk waste. India produces annually about 180 tonnes of spun silk yarn and 130 tonnes of noil yarn besides hand spun yarn.

Why Silk Reeling using Charkha is inferior

Silk reeling, using country charka is of low quality but it contributes more to the raw silk produce. The reasons

for low quality silk in country charka are as follows;

1. No sorting of cocoons. Defective cocoons are also reeled.

2. No cocoon mixing

3. Improper deflossing.

4. As there is no jettebout the dirt, gum spots etc., can be eliminated. However, the charka has Tharpatti but

cannot function like button or jettebout.

What are cocoons, what are they made up of

Cocoons

Cocoon is nothing but a protective shell made up of a continuos long protein silk filament spun by mature silkworm

Content Percentage

Fibroin 72.0-81.0

Sericin 19.0-28.0

Fat & Wax 0.5-1.0

Colouring matter & ash 1.0-1.4

What are important physical and commercial characteristics on which the production and quality of silk depends

Color

Indian races produce either white or yellow cocoons and white cocoons have a slight edge over the yellow cocoons in market price.

Shape

For easy relling spherical, oval and moderately constricted or printed cocoons are selected.

Size

The size is generally indicated by the number of cocoons per litre.Generally the number of cocoons per litre varies between 110 to 400. Uniform sized cocoons are required for reeling.

Hardness or Compactness

When a cocoon is lightly pressed between the fingers, it should not yield but should feel firm, compact and

elastic.

Grain or Wrinkle

After deflossing the cocoon surface should be granual or wrinkled with convolution.For better reeling fine granular cocoons are selected.

Weight of Cocoon

Weight of Cocoon Shell

Larger the weight of the shell, greater the silk yield.In Indian multivoltine hybrids the shell weights is 200 to

300 mg. , while it is 180 to 250 mg in multivoltine pure races. Indian univoltine cocoons have 200 and 300 mg of silk shell.

Commercial Chracteristics

1. Shell Ratio: It indicates the quality of raw silk that can be reeled from fresh cocoons. Shell ratio is the

weight of cocoon shell and weight of whole cocoon. . It varies from 12 to 19 per cent.

2. Length of filament

It denotes the length of silk in the cocoon. It varies from 300m to 1200 m.However non breakable filament length (NBFL) which is the average length of filament that can be unwound without breaks is very important.

3. Weight of reelable filament

The complete silk filament of the cocoon cannot be reeled. The outermost floss layer and innermost pelade layer cannot be reeled and therefore removed.

4. Denier

It determines the size of silk. The denier is high in outer floss layer than the middle or inner layer.The tolerance limits for the commercial raw silk are 13/15, 20/22 denier. Denier = ( Total weight of reeled silk in grams/Total length of reeled silk in meter) x 1000.

5. Raw Silk Percentage

This is the percentage of the quantity of raw silk reeled in relation to the quantity of fresh cocoons used for

reeling. This can vary from 40 to 85 per cent. Raw silk Weight = ( Wt of Reeled silk/wt of cocoon)x 100

6. Floss

It is the value outermost loose, fragmented unevenly thick silk layer of the cocoon. It is a waste silk.

7. Renditta

It is the value derived from liter of cocoons required to produce one unit (1 kg) of raw silk. It varies from 6 to

14. The lower the value, the better is the quality of Silk.

What are the various steps of Silk Manufacturing after the cocoon is ready and collected

The various steps are as follows

1. Cocoon Stifling and Conditioning

The process of killing the pupa and keeping the cocoon in good condition by storing in a proper conditions is

called stifling and conditioning of cocoons.

a. Stifling of Cocoons

It can be done by

- Sun Drying

- Steam Stifling

- Hot Air Drying

Sun Drying

It is a method of killing and drying the pupae by prolonged exposure of freshly harvested cocoons to hot sun. It is simple and cheap and drying is even/uniform. However, it is not suitable for modern reeling, can only be done on bright days, prolonged exposure can cause poor quality silk, increases wastages of silk reeling, involve space and labour and the cocoons can get dust and dirt in the process. Tussar in India uses sun drying method.

Steam Stifling

In this process, the fresh cocoons are exposed to hot wet steam, for a required period. Large quantity of cocoons can be stifled in a short time. However, it kills the pupa inside and doesnt dry it properly. There is also a problem of mould formation and leaking of body fluids of pupa onto silk. It also affect the sericin, increasing silk waste.

Hot Air Drying

In this the pupae are killed by exposure to hot air. It is the best method of stifling, giving good quality of silk

and dried pupae.

2. Cocoon Storage

After complete drying, the cocoons are to be stored in a store house which is protected from rats and is moisture proof.To protect the cocoons from fungal attack, the inside temperature and relative humidity of the store need to be maintained at 27 deg C to 30 deg C with 60-70 per cent relative humidity.

3. Cocoon Sorting

Sorting of Cocoon is done before reeling to give good quality cocoons.

4. Deflossing

Generally deflossing is done by fingers but now simple hand operated machines are also available.

5. Riddling

It is a process that separates the cocoons according to their sizes.

6. Cocoon Cooking and Brushing.

Silk thread spun by silkworms is technically called as ‘bave’. This is a composite structure which inturn has two filaments inside which are known as ‘brins’. Brins are the filaments which are produced by the two silk glands. Brins are made up of silk protein biborin synthesized in the silkglands. The brins are intrun bound by silk protein called sericin.

The cooking process is done for softening the sericin to facilitate easy unwinding of the silk filament at the same time.The sericin content of the silk filament ranges from 25 to 30 per cent, which varies in different races. In cooking process 7 to 8 per cent of sericin is dissolved.

In order to cook the cocoons properly there are different types of systems of cooking.

1. Top reeling or floating system

2. Sunken system

In top reeling the cocoon shell becomes wet and impervious to water and float in water when the cooked cocoons are put in to the reeling basin. In sunken system the shell is cooked and the process fills the cocoon with water (97- 98 per cent) and makes the cocoon heavy and which sink in the reeling water. The top reeling is a old method while sunken reeling is a latest method.

Traditionally tassar cocoons are cooked in an earthen pot at or near boiling sodium carbonate (washer man’s soda) solution for 4-6 hours. Cocoons are then reeled in semi moist condition on Natwa/Thigh, where the productivity per day per reeler comes to about 60-80 g of 60 D silk yarn.

Brushing

The cocoons have to be brushed to remove the surface floss before reeling. Floss is a lossely knit, broken, uneven thickness, water silk. Without removing the floss layer one cannot reel the proper silk. This waste layer obstructs the reeling process unless it is clearly removed. The process of removing floss layer is called “brushing”.Brushing can be done with the help of a stick, a brush or through mechanical means.

---to be continued---

Comparing Silk Fabrics from China and India

2011-12-20T08:26:00.002+05:30

The following are the major differences between Silk Fabrics made from China and India.

1. The raw silk produced by Chinese producers is qualitatively better because they employ dried cocoon reeling method as compared to the Indian silk producers who employ fresh cocoon reeling method to obtain raw silk.

2. Majority of Indian silkworms are multi-voltine variety, whereas Chinese silkworms are of the bi-voltine variety, which has high productivity of cocoon per acre, and the cocoon has higher silk output per kg, and the silk has higher tensile strength on the loom.

3. The machinery used by the Indian producers are obsolete, simple and inefficient which is the primary cause for the higher per unit value of Indian silk as compared to Chinese silk.

4. The twisting machines used by Indian producers to produce silk yarn can reach 800 twists per minute at the most. However, the twisting machines used by Chinese producers are advanced and can reach a number of twists of more than 2600 twists per minute the resultant product being of high quality.

China and India together account for more than 90% of the total production of the 20-100 grams of silk fabric variety in the world; China producing approximately 78% and India approximately 15% being the two major producers of silk in the world.

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Difference between Kora and Katan

2011-12-19T07:44:00.000+05:30

This terminology is used in context of Varanasi Saris. In general, warp yarn is not degummed while weft yarn is degummed. Warp yarn is can be single or two ply. Weft yarn is twisted-two ply.

Non degummed two ply yarn is called Kora. When it is degummed, it is called Katan.

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Kota Saris- My Thoughts

2011-12-11T23:01:00.001+05:30

Kota sari weaving is at the crossroads. At least I think so. With my recent visit to kota sari weaving clusters in Kota, Bundi and Baran Distt, I have come to conclusions which are very different to those I previously had. One, the battle between handloom and powerloom Kota is clearly one-sided in favour of powerloom. In clusters it is a battle between master weavers and labourers. Kota has started adopting techniques of Chanderi saris in a big way. With influence of retail chain and designers, the Kota is being experimented on different bases. With all that at background, the uniqueness of Kota sari weaving is still prevailing. With the continuous increase in the price of traditional raw material and labour, and with decreasing prevalence of saris, the road ahead for Kota weaving is quite bumpy.

Image: pictures.kotasaree.co.in

1. Handloom Vs. Powerloom

Handloom weaving in Kota Sari has shrunk itself in tiny clusters around the district. With about 2000 handlooms in the ten or so clusters around the towns, the handloom weaving is struggling to survive the onslaught of powerloom fabric being thrown in from Varanasi and from Kota itself. The difference in the price is staggering. A plain handloom sari of 5.5 meter will cost you 1200 whereas the same sari in powerloom you can get under 300 or so if you are a good bargainer. Real zari prices will sky rocket the MRP whereas in Tested Zari they become affordable. And go to Bhairo Gali in Kota, the shops are brimming with powerloom material in tested zari at prices that will take your breath away. The only solace for Kota handloom weavers is the traditional Jamdani technique which can only be done on a handloom fabric. In fact the entire village of Kaithoon is surviving on this. However, go to markets and you get a cutwork variety of the fabric in both pallu, body and border. Number of Khats are shrinking to about 240 in powerloom whereas they are still 290-300 in the handloom fabric. Talking of Khats, I happen to see a sari in 400 khats with one of the master weaver in Kaithoon. In Kaithoon, they have stopped producing the plain poth or simple Kota material without buti, as the workers do not get enough margins. This can directly be tracked to the powerloom version of plain poth saris.

2. Master Weavers vs. Labourers

The rift is evident. Some clusters like Kaithoon has a plethora of master weavers whereas the others such as Kotswan have all laborers. They even said that they are being exploited by the master weavers and would like to become independent. But they don't have the marketing wherewithals. The difference is also evident in their life styles. Whereas master weavers are living in plush lifestyles, the laborers are facing destitution. Even between villages the difference in the lifestyle of master weavers is stark. A master weaver in Kaithoon is much more rich than that in Ratoda. As indicated in the previous paragraph, the weavers in villages other than Kaithoon are ready to do even plain poth.

3. Chanderi influence in Kota

It is not clear if the motifs and techniques are originally from Kota or from Chanderi. However the difference is minimal. Using the same "Jala" technique ( In Chanderi they call it "Nakka") they are putting motifs in the pallu using "Tillis". In powerloom, they are using Jacquards and producing motifs in the cutwork technique. The motifs are so similar to Chanderi that it is difficult to guess who is copying whom. However, one difference in handloom separates Kota from Chanderi. Apart from texture, in Kota they are still using real zari. The looms are also much smaller than chanderi.

4. Experiments on New Bases

With the powerloom rapidly gaining ground, new bases are being experimented upon. Using Silk with Katan makes the Kota texture very soft and lightweight. Using china silk with Silk gives a medium stiffness. However they are using China x china and that gives Kota sari a very unique finish. They are also using zari to make tissue saris out of it. Use of Dyed yarns will give a very different textures to the saris.

5. Different Areas Different Emphasis

One observation while visiting clusters I made is different clusters are specialised in different techniques. In Kaithoon, they specialise in Buti weaving using Tillis. In Kotswan they are working on plain poth using different bases. In Ratoda, they are working on Kota saris with zari checks for traditional Rajput wedding. In Mangrol, they are working on different bases.

6. Uniqueness Still Prevails

All said and done, the texture that Kota sari produces in inimitable. With options of so many bases using yarn dyed and butis with border options, they become a language in themselves.

7. Road Ahead

Handloom in Kota is dyeing like any other handloom cluster. The progeny of the handloom weavers doesn't want to work on traditional looms. With designs being copied by everyone else, and powerloom option coming the second day with half the price, weavers are dyeing a slow death. Buti option in Jamdani technique still makes the saris unique. With GI in place, and government supporting Kota weavers, it makes the life of the weavers somewhat comforting. However this incentive is artificial and until some unique design interventions are done in Kota saris, the handloom extinction is only an arm's length away.

A Layman's Review of Silk

2011-11-22T22:51:00.001+05:30

What is Silk

Silk is a continuous protein filament secreted by specific types of caterpillars commonly known as silkworms. It is the most loved fiber the world over. Natural sheen, inherent affinity for rich colors, high absorbency, lightweight (yet stronger than a comparable filament of steel), poor heat conduction ( warm in winter, cool in summer), low static current generation, resilience, and excellent drape are some of its irresistibly endearing qualities.

Varieties of Silk

Mulberry

This is the most commonly known and understood form of natural silk.

Mulberry silk is light weight, has a natural sheen and smooth feel. Majority of finished silk products available in the market are made from mulberry silk.

The mulberry silk worm feeds on mulberry leaves and forms a smooth cocoon, from which yarn is taken out through a process called reeling.

Mulberry silk is a rich absorbent of colors and is a printer's delight.

Vanya Silks or Wild Silks ( Tasar, Eri and Muga)

India's Wild Silks or Vanya Silks reflect the exotic and untamed spirit of wild silk worm...in texture, feel, sheen and color. It has inspired designers to create distinct fashion statements in clothing and home textiles.

Vanya Silks have baffling thermal properties, keeping warm in winter and cool in summer.

Vanya Silk portray the rich crafts culture and folklore of the North Eastern and Tribal zones of Central and Eastern India. They are of three different types, each distinct in its characterisics, Tasar, Eri and Muga.

Tasar

The tropical or Indian Tasar Silks are highly textured and have a wide range of natural colors from off-white to beige and gold brown. It has a dull, uneven sheen and can also be dyed in a number or colors and easily blended with cotton, wool, linen or other silks.

Well known Bafta fabric is a blend of India Tasar with cotton. Tasar is used in both spun and filament form. Tasar silkworms feed mainly on Asan and Arjun leaves. India is the second largest producer of Tasar silk in the world.

Desi or Indian Tropical Tasar is produced by the species of worms known as Antharaea Mylitta. There is another variety of Tasar which is called Oak Tasar. It is produced by another species of worms called Antharaea Proyeli (produced in India ) and Antharaea pernyi (produced in China). It is a finer variety of Tasar.

Eri

Also known as Endi or Errandi Eri silk is produced by Eri silkworm, which mainly feeds on Castor and Kesseru leaves.

Eri can be spun in coarse to very fine yarns and is home washable. It can also blend with cotton, wool, jute and mulberry silk.

Eri silk gains better sheen with every wash. Its high warmth retention makes it very comfortable in cooler climes. It is popularly used for making Shawls, Stoles, Fashion accessories and Home Furnishings.

Muga

The shimmering golden color, distinct look and smooth feel of muga is an instant inspiration to the interior, home and fashion designers all over the world. Muga commands highest premium amongst all silks.

Reared in Assam, the Northeastern region and Cooch Behar in West Bengal, Muga silkworms feed on Som and Sualu Leaves.

Muga yarn is generally used in the Assamese homes for home furnishings. The famous Sualkuchi sarees too are a product of Muga silk.

Silk Care

Precautions during washing ( Source : Silkmark Brochure- Please try separately before following instructions)

1. Always wash silks in soft water. Add a pinch of Borax or ammonia, if the water is hard.

2. Use a good neutral soap in the forms of either flakes or solutions.

3. Light detergent may also be used in the case of hard water.

4. Wash in lukewarm water by kneading and squeezing or suction.

5. Rinse in warm water 2-3 times to remove traces of soap.

6. Add a few drops of citric acid or acetic acid to the final rinse in cold water.

7. Silk with doubtful color fastness may be steeped in cold water with a small amount of citric or acetic acid for 1-2 minutes before washing. Squeeze lightly by hand to remove water.

8. Always dry flat, in shade.

Precautions during Ironing

1. Use Low to medium heat

2. Never spray water to dampen silk before ironing. This will cause water spots in the fabric.

3. Silk should always be ironed on the reverse side if still damp.

Storage of Silk Products

1. Store in cool and dry place in brown craft paper covers.

2. In case of sarees avoid stacking more than three, frequently reverse and change the folds. A small sandal wood piece instead of naphthalene balls would provide dry, cool and fresh air. Sweat should never be allowed to settle and should be removed by rinsing in cold water.

3. Hang the silk products in good ventilated wardrobe or cupboard.

4. Use anti-mildew compound spray.

5. Warp in muslin cloth to avoid discoloring of zari.

6. Use natural perfume like Sandalwood swatch for refreshning.

7. Plastic bags given as package material after laundering or purchase should not be used for storage.

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Care Instructions for some of the Traditional Cotton Printed Fabrics

2011-11-07T11:18:00.000+05:30

Dabu, Ajrak and Khadi Printing

1. Hand wash in cold water with mild soap, hang to dry and
press with a dry iron.

2. Machine wash in gentle cycle with
cold water and mild soap, do not put in dryer.

Silver and Gold Foil Block Printing

1. Do not wash or do not dry clean. Silver and Gold Leaf will tarnish and spoil if laundered.

2. Store these precious items in a cool dark place with leaf facing inward.

3.Rolling is preferable to folding with acid free tissue or unbleached cotton between layers of cloth.

Hand Dyed and Block Printed

1. Hand wash in cold water with mild soap, hang to dry and press with a dry iron.

2. Machine Wash in Gentle Cycle with cold water
and mildsoap, do Not put in Dryer.

3. SILK Dry Clean Only

Cotton Bandhini

1. Hand wash in cold water with mild soap, hang to dry and
press with a dry iron.

2. Machine wash in gentle cycle with cold water and mild soap, do not put in dryer

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Common Printing Defects in Screen or Roller Printing

2011-10-18T08:18:00.002+05:30

The following printing defects are frequently observed in screen or roller printing:

1. Scrimp

During the printing process the fabric sometimes creases under one of the screen during the printing process. Thus the pattern is printed on the top of the screen. When the crease is removed, it leaves a large area of the fabric unprinted.

2. Misfit or Out of Registration

A misfit is a defect caused when screens are not properly aligned. The misaligned screens can leave an area unprinted or cause the pattern overlap on one another.

3. Stick-in

A stick-in occurs when a small fiber or yarn get stuck in one of the screen openings. It can result is a small unprinted circle in the design of the size of the tip of a pen. A stick-in is very difficult to see and often go unnoticed.

4. Wicking or Flushing

It occurs when the printed area bleeds out into the unprinted area. This results in a "haloing" or shadowing effect around the outline of the pattern design. Wicking is often caused by residual salts left in the fabric during resign finishing or during fabric preparation.

5. Doctor Streak

It refers to a wavy white or colored streak in the fabric in the warp direction. It is called so because it is caused by damaged or improperly set doctor blade in the printing machine. A doctor blade is a metal knife that cleans or scrapes the excess dye from engraved printing rollers, leaving dye paste only in the valleys of engraved areas.

6. Mottled

It results from the color applied unevenly during printing

7. Printing Machine Stop

As a result of printing machine stop the dye sometimes is smudged along the width of the fabric.

An excellent description of defects in digital printing can be found here.

What are Plisse and Burnout Prints

2011-10-17T07:57:00.002+05:30

Plissé Prints

The plisse prints are created by application of strong alkali to 100% cotton fabric. The alkali is applied in a pattern. After some time ( usually several minutes) the fabric is washed so that the alkali is removed. This results in the shrinkage of fabric from those areas where alkali is applied. This shrinkage causes puckering in the areas where alkali is not applied. A seersucker type appearance can be given to the fabric by applying the print pattern in parallel stripes. The alkali can be applied using direct or resist methods.

http://ny-image0.etsy.com

Burn Out Prints

A beautiful "burn out" effect can be created by applying strong mineral acids or acid salts in the selected areas of a cotton polyester blended fabric. The acids will cause cotton to be destroyed and the polyeste rremains. Thus very beautiful lacey designs can be imparted to the fabric. Also in the burn out paste, a disperse dye can be incorporated which will also dye the polyester which burnout is taking place. However, due to the corrosive nature of the process special protections need to be taken.

For more information about plisse and other finishes, click here.

Motifs in Patola Saris

2011-10-15T08:28:00.000+05:30

Ratanchowk

Kesar Chandan Design

Chhabdi Bhaat

Chanda Bhaat

Naari Kunjar Design

Five Phool Bhat

Three Phool Bhat

Sarvariya Bhat

Vora Gaji

My Notes about Textile Books: Fabric Analysis

2011-10-15T08:04:00.000+05:30

An excellent book on fabric analysis can be found here.

This book is unique is the sense, that it takes care to analyse the fiber contents in common fabrics.

It gives detailed explanation on the following (among others):

1. Distinguishing between cotton and silk, silk and linen
2. Distinguishing between Weighted and Normal Silk.

I haven't tested the chemical procedure described in the book. Users are advised their discretion. And yes, this book is quite old, so don't expect to find treatment on Synthetic fibers.

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Difference between Blended Fabrics and Union Fabrics

2011-10-15T07:42:00.001+05:30

Blended Fabrics are made up of blended yarns. Blended yarns contain fibers of different composition in fixed proportions. Thus a blended fabric may be made of polyester/cotton in 67:33 ratio in both warp and weft.

Union fabrics are the fabrics where in the fibre content of warp is different form that of weft. Thus a Silk/Viscose union fabric may have silk in the warp and viscose in the weft.

An excellent study on silk/viscose union fabrics can be found here.

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Effluent Tratement- Kerosene Recovery from Pigment Printing

2011-10-06T10:57:00.002+05:30

Effluent Treatment- Kerosene Recovery from Pigment Printing

In India about 46% of the total printing is done using pigment printing method, 27% using reactive dyes, 15% Disperse dyes, 2% napthol, 3% acid and 7% using vat colors.

In a typical pigment printing paste, 75% is keorsene, 10% is binder, 5% each is gum and water, 2% urea and 1% each of DAP and emulsifier. Kerosene water emulsion acts as a thinkner is pigment printing. Its use is prohibitied in most of the developed countries. Alternatives to kerosene are synthetic thickners but they make the printed fabric stiff.

In India alone, about 140 thousand kiloliters of kerosene per annum is consumed during the process of printing and drying. Out of the total kerosene applied, about 22% is lost at various points during this process( 1 % is left out on the fabric, 12% screen printing and wastage, 5% is before dryer, 4% is at curing machine and 78% is released or evaporated in the atmosphere during the process of drying at 120-150 deg C). It signifies a loss of precious kerosene as well as pollution in the environment.

Apart from the effluents generated during wet processing, there is a substantial amount of kerosene vapour that is released in the air in the process of pigment printing.

Any kerosene recovery process should be based on the fact that kerosene is liquid at room temperature and immiscible with water. The kerosene vapour are at 120 deg C and they have to be cooled below 40 deg Celcius. The kerosene and water will separate out in two layers, with top layer can be skimmed for reuse.

An excellent effluent treatment plant is proposed by BTRA. Average recovery is 58% whereas maximum recovery can be 85%. Read more about it here

To view the pigment printing process and alternative to kerosene, please find the link here.

Process Flow of Effluent Treatment in a Textile Industry-1

2011-10-04T08:52:00.001+05:30

Process Flow of Effluent Treatment in a Textile Industry

Typically the following process flow of effluent treatment is followed in a typical textile industry;

Screening

The purpose of screening is to filter out the loose impurities. Thus wood, paper plastic bags etc. can be removed by this method. A method of progressive filtering is followed where first the matter is passed through coarse screens and then through fine screens.

Oil and Grease Removal

Many units discharge water mixed with oil. The purpose of this equipment is to remove the oil. Since surface density of oil and grease is less than water, the oily substance come on the surface of the water and can be skimmed.

Cooling and Equilization

The effluent from the primary treatment is cooled ( cooling towers are employed for this purpose) and then uniformly mixed using equlisation tank. It takes in any sudden gush of effluents as well as slow rate of effluent and feeds to the subsequent processes in a uniform way.

pH Adjustment ( Acid or Alkaline Dosing)

The waste from the Textile Industry is rarely pH neutral. To increase the efficiency of biological treatment and coagulation/flocuculation a pH of 6-8 is needed. Generally Sodium hydroxide is used to neutralise acidic waste and hydrochloric acide is used to neutralize alkaline waste. Generally the effluents from the dyeing industry have high pH and hence an acid addition is required.

Aeration

It is reuqired to control BOD. Two main methods are used: one in which water is mechanically agitated so that air from atomoshphere may enter into the water, second method is introducing the air in the water through blowers and using diffusers to diffuse the air uniformly.

Prechlorination

Generally organic matter present in the effluent takes oxygen from the water, which increases its oxygen demand, to avoid that chlorine is added to oxidise the matter.

Clarification

The purpose of clarification is to remove any suspended solids by coagulation and flocculation. It is done using flash mixer. In flash mixer, alum solution is dosed as coagulant.

The flocculated water flows upwards towards tube settler. The suspended solids settle down.

This settling can also be done using lamella filter

Lamella Filter

It achieves solid liquid separation by directing the liquid between a seris of inclined plates called lamellae. It settles suspnded solids by gravity.

To be continued

An Excellent Document on Denim Effluent Treatment Process is here

Sources:

http://www.scribd.com/doc/4678823/Etp-Manual-Std-Denim

http://www.sharpengineering.co.in/Iffluent_Equipments.aspx

http://www.jfc-cetp.com/envinfo.html

http://www.iichemrc.org/Lamella.pdf

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Effluent Generated at various Processes of Textile Manufacturing

2011-10-02T08:18:00.001+05:30

Effluent Generated at various Processes of Textile Manufacturing

Textile manufacturing involves conversion of Fibers into garments. At each process some amount of liquid is used. However, it is not that each process leads to generation of efflents. Typically coversion to yarn involves no generation of effluents. It is the sizing and processing where most of the efflent is generated which needs to be treated. Given below is a list of the processes along with the information about effluent generated.

1. Fiber Preparation and Yarn Spinning:

There is very little effluent generated in these processes.

2. Slashing/Sizing

The Effluent contains BOD, COd, metals, cleaning waste and size.

3. Weaving, Knitting and Tufting

There is very little effluent generated in these processes.

4. Desizing

The effluent contains BOD from water-soluble sizes, synthetic size, lubricants, biocides and anti-static compounds.

5. Scouring

The effluent contains disinfectants and insecticide resudes, NaOH, detergents, fats, oils, pectin, wax, knitting lubricants, spin finishes and spent solvents.

6. Bleaching

The effluent contains hydrogen peroxide, sodium silicate or organic stabilizer. The effluent also contains high pH.

7. Singeing and Heat Setting

There is very little effluent generated in these processes.

8. Mercerising

The effluent contains high pH and Sodium Hydroxide.

9. Dyeing

The effluent contains metals, salts, surfacftants, toxics, organic processing assistants, cationic material, color, BOD, sulfide, acidity or alkalinity and spent solvents.

10. Printing

The effluent contains suspended Solids, urea, solvents, color, metal, heat , BOD and foam.

11. Finishing

The effluent contains BOD, COD, suspended solids, toxics and spent solvents.

Read Also

Textile Effluent Treatment-1
Textile Effluent Treatment-2

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Effluent Treatment in Textile Industry-2

2011-09-30T08:55:00.001+05:30

Bleaching and Dyeing

It is estimated that to dye 1 kg of cotton with reactive dyes, 0.6-0.8 kg of NaCl, 30-60 grams of dyestuff and 70-150 liter of water is required. Once the dyeing operation is over, the wastewater must be treated before reuse. Coagulation and Membrane Technique ( nanofilteration or reverse osmosis) are among the processes suggested for the treatment of water.

Coagulation and Flocculation

Natural and wastewater contain small particles. They are suspended in water in a form called as a colloid. These particles carry the same charges, and repulsion prevents them from combining into larger particles to settle. Thus, some chemical and physical techniques are applied to help them settle. The phenomenon is known as coagulation. A well known method is the addition of electrolyte. Charged particulates combine with ions neutralizing the charges. The neutral particulates combine to form larger particles, and finally settle down. Historically Alum is used for this purpose but it makes the pH of the solution slightly basic.

Another method is to use high-molecular-weight material to attract or trap the particulates and settle down together. Such a process is called flocculation. Starch and multiply charged ions are often used.

Here the basic advantage is that the dye molecules themselves are removed which is better than other methods where dye molecules are decomposed and produce harmful and toxic aromatic compounds.

The disadvantage is that in coagulation process, large amount of sludge is created which may become a pollutant itself and increase the treatment cost.

This method is useful for removing the insoluble dyes, but the cost of treating the sludge increases.

Ultrafilteration and Nanofilteration

Ultrafilteration filters substances with sizes less than than 10^-7 to 10^-8 m . It can effectively remove suspended organic solids. It can not remove multivalent ions. It needs low water pressure to operate.

Nano filteration filters substances with size less than 10^-8 to 10^-10 m. It can remove multivalent ions.

Reverse Osmosis

It can remove substances with size less than 10^-9 to 10^-11m. It can remove multivalent as well as monovalent ions.

When a compartment containing a dilute solution is connected to another compartment containing a concentrated solution by a semipermeable membrane, water molecules move from the dilute solution to concentrated solution. This phenomenon is called osmosis.

By applying pressure in the higher concentration solution, water molecules migrate from a high concentration solution to a low concentration solution. This method is called reverse osmosis water filter system. ( Source )

An excellent FAQ on Reverse Osmosis can be found here .

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