Textile Notes related to fiber, yarn, fabric knowledge, spinning, weaving, processing, projects, knitting, Indian Traditional Textiles and denim manufacturing
I remember my days when after doing my graduation in Textile Technology I was thinking of joining a textile company. There was no viable alternative possible for a textile engineer like me. However, technology has changed the nature of the game.
Media and Entertainment has emerged out to be one such sector that is independent of one's background. It also has the potential to fill in the creative void in an individual that emerges due to study of a relatively drab subject such as textile technology.
Prima facie, there is no dearth of jobs in media and entertainment industry. Jobsites suggest that there is also a high growth rate in such jobs. This is particularly important in a recession hit economy where other jobs are getting relatively scarce.
A conference is taking place on Saturday, July 25, 2009 at Chelmsford Club, #1,Krishi Bhawan, Raisina Road, New Delhi H.O.Delhi 110001, organized by 9.9 School of Convergence. The objective of the conference is to bring together the topshots in media and entertainment industry to discuss about the job opportunities created in this sector, among other related issues.
The keynote speakers will include Karan Makhija, Film Actor, Jaane Tu Jaane Na and 9.9 SoC alumni, Ranabir Majumdar, Editor-Cricketnext.com, ESPN Star and 9.9SoC alumni and Dr. Pramath Raj Sinha, Dean, 9.9 SoC , CEO 9.9 Mediaworx, Founding Dean ISB.
I recommend the readers to attend the conference and give their valuable feedbacks.
12 things to Ensure While Marking Master in Garment Manufacturing
1. Do it only on the selected marking material
2. Ensure Number of patterns necessary for each style to make a complete garment.
3. Ensure facing of the patterns ( faceup, down, lateral, longitudinal) to facilitate cutting in design direction. Provide identification mark with respect to spread type eg. "FU" for face up, "FD" for face down and "FF" for face to face.
4. Determine the grain marking on pattern such as straight, cross and mixed.
5. Note the warp (straight), weft (cross) and bias grain dimension of each pattern.
6. Ensure that the grain alignment on the marker is within the graining tolerances as specified on the pattern.
7. Mark the pattern wholse widths sum up to equal the fabric width shall be marked in parallel formation across the width.
8. Achive maximum interlock efficiency of patterns with tapered width by inverting the alternate pattern depending on the fabric design.
9. Avoid crowding of interlocking angles and curves which restrict the cutters ability to cut the pattern section with precision.
10. Provide sufficient knife clearance for manipulation of cutting machine at interlocking curves and angles.
11. Draw lines with precision ( line value to facilitate cutting)
12. Mark each pattern section with its size, style and pattern title/number.
"There are no bad dyes - only bad dyers" is the punch-line of Batik Oetoro , who are suppliers of textile materials, service and know-how to the artists.
The website is well structured and brimming with information.
Click on dyes and you get to see a colorful assortment of dyes. Move down and you will find the dyeing instructions for that class of dyes. There is also a dye receipe for hand painting of the fabrics. Also dyeing instructions for all possible applications are given. For example the following techniques are explained for acid dyes:
Under "Fabric Decorating", some marvellous techniques using dyes such as Devore and Marbelling are given.
Though the site was last updated in 2008, you can get an idea about the cost comparison of the different classes of dyes.
There is also an automatic calculator which convert virtually every weight and volume measurement into teaspoons. I really love their most comprehensive instructions on natural dyes . They also have instructions for dyeing silk/viscose blend. For the curious, they have a list of common names used for chemicals . For the beginner a summary of dyes is given. Of course, they have a glossary of terms .
How to Determine the Weight of Pile Warp in Terry Towel
Weight of Pile Warp = weight of pile warp in pile part + that in plain part + that in fringe a. Weight of pile warp in pile part ( Pile ratio: 52:10) =( Length of pile part x number of pile threads x pile length x yarn count in tex) / (100 x 1000) = (102 x 576 x 52 x 30 x 2)/(100 x 1000) = 183.31 g
b. Weight of Pile warp in Plain Part =( Length of plain fabric x number of pile threads x crimp factor x yarn count)/ (100 x 1000) = (4 x 576 x 1.08 x 30 x 2)/(100 x 1000) = 1.49 g
c. Weight of Pile warp in fringe ( No crimp , no loop ) = (fringe length x number of pile threads x yarn count)/(100 x 1000) = (2 x 576 x 30 x 2)/(100 x 1000) = 0.69 g Weight of pile warp = 183.31+ 1.49 + 0.69 = 185.49
How to Determine the Weight of Weft in Terry Towel
Weight of Weft Yarn
= (Total no of weft threads x reed width x yarn count)/(100 x 1000) (Reed width is equal to the length of one weft yarn) = (106 x 20 x 58.4 x 34)/(100 x 1000) = 42.09 g
Calculating the Weight of Ground Warp in a Terry Towel
A terry towel is different from an ordinary woven fabric because it has a looped surface. These loops are responsible for the towel’s softness, bulk, absorbency and characteristic hand feel. Unlike a simple plain woven cloth, a terry towel normally uses two warp systems and one weft system. These are the ground warp, pile warp and weft.
The ground warp forms the foundation of the towel. It gives strength and stability to the fabric. The pile warp forms the loops on the surface. The weft binds the warp systems together and helps create the final towel structure. In this article, we shall calculate only the weight of the ground warp used in one towel. The pile warp and weft calculations can be taken separately.
In a terry towel, the pile loops are not accidental. They are deliberately formed by controlling the movement and tension of the pile warp during weaving. The pile warp is usually kept under lower tension than the ground warp, so that it can be pulled forward and formed into loops. The ground warp remains more tightly controlled and works as the structural base of the towel.
This is why terry towel weight calculation is not done exactly like a simple flat fabric calculation. We have to treat each yarn system according to its function in the fabric. The ground warp, pile warp and weft do not consume yarn in the same way. Their yarn counts, lengths, crimp values and structural roles may be different.
Visual 1: Basic terry towel structure showing ground warp, pile warp and weft.
2. Given Data
Let us assume the following construction details for the towel. These values are used to explain the method of calculation. In practical mill work, the values should be taken from actual fabric construction, loom settings, yarn count records and production data.
Parameter
Value
Length of grey towel
106 cm
Number of ground warp ends
694
Ground warp count
\(25 \text{ tex} \times 2\)
Warp crimp
8%
Warp crimp factor
1.08
Fringe length
2 cm
The ground warp count is given as \(25 \text{ tex} \times 2\). This means that the yarn is a two-ply yarn. Each ply is 25 tex, so the effective yarn count for calculation is:
\[
25 \times 2 = 50 \text{ tex}
\]
3. Understanding Tex
Tex is a direct yarn count system. It tells us how many grams are present in 1000 metres of yarn. In direct count systems, a higher tex value means a heavier or coarser yarn, while a lower tex value means a finer yarn.
\[
\text{Tex} = \frac{\text{Weight in grams}}{1000 \text{ metres}}
\]
So, if a yarn is 50 tex, it means that 1000 metres of that yarn weighs 50 grams. This makes tex very useful for calculating yarn weight when the length of yarn is known.
Practical point: Whenever tex is used, the length must ultimately be converted into metres. Since towel dimensions are often written in centimetres, the centimetre-to-metre conversion must be handled carefully.
4. Why Ground Warp Is Calculated in Two Parts
The ground warp is present in two places. It is present in the main grey fabric body of the towel, and it is also present in the fringe portion. These two portions are treated separately because the yarn behaviour is different in both areas.
In the grey fabric body, the ground warp interlaces with the weft. Because of this interlacement, the yarn does not remain perfectly straight. It follows a slightly wavy path. This extra length is called warp crimp or warp take-up.
In the fringe portion, the yarn is generally considered to be straight and loose. Therefore, warp crimp is usually not added to the fringe calculation in a basic estimate.
\[
\text{Total ground warp weight}
=
\text{Ground warp in grey fabric}
+
\text{Ground warp in fringe}
\]
5. Formula for Ground Warp in Grey Fabric
The formula for calculating the ground warp weight in the grey fabric body is:
The denominator \(100 \times 1000\) is used for unit conversion. The fabric length is given in centimetres, while tex is based on metres. Since \(100 \text{ cm} = 1 \text{ metre}\), and tex is based on \(1000 \text{ metres}\), the conversion factor becomes:
\[
100 \times 1000 = 100000
\]
Visual 2: Ground warp calculation flow from construction data to yarn weight.
\[
\boxed{\text{Weight of ground warp in grey fabric} = 39.72 \text{ g}}
\]
7. Why Warp Crimp Is Important
Warp crimp is the extra yarn length required because of interlacement. In a woven fabric, warp yarns pass over and under the weft yarns. This makes their actual path longer than the straight fabric length. Therefore, if we calculate warp consumption only from the straight fabric length, we may underestimate the yarn actually required.
If the fabric length is 100 cm and the warp crimp is 8%, the actual yarn length consumed is:
\[
100 \times 1.08 = 108 \text{ cm}
\]
So an 8% crimp means that for every 100 cm of fabric length, 108 cm of warp yarn is required. In this example, a crimp factor of 1.08 has been used:
\[
1 + \frac{8}{100} = 1.08
\]
In actual production, warp crimp may vary depending on yarn tension, weave structure, reed setting, picks per cm, finishing shrinkage and loom conditions. Therefore, crimp should ideally be taken from mill records or measured from actual fabric samples.
8. Formula for Ground Warp in Fringe
The fringe length is calculated separately. The formula is:
In this basic calculation, crimp is not added to the fringe because the fringe yarn is not interlaced like the main fabric body. However, for a detailed production costing, fringe trimming, knotting, twisting and wastage may also have to be considered.
At first glance, the ground warp weight may appear small. However, this is understandable in terry towel construction. A terry towel is not a flat fabric where the ground warp, weft and total fabric weight are closely balanced. In a terry towel, the pile warp contributes a major share of the final weight because the pile warp forms the loops.
The ground warp is mainly a foundation system. Its purpose is to hold the fabric together and provide dimensional stability. It is not expected to contribute the largest portion of the towel weight. The pile warp, because of its loop formation and pile ratio, normally consumes much more yarn than the ground warp.
Visual 3: Conceptual comparison of ground warp, pile warp and weft contribution in a terry towel.
12. Practical Notes for Textile Calculations
This calculation is a basic yarn consumption estimate. It is useful for understanding how ground warp weight is calculated, but actual mill calculations may require additional allowances. In production, theoretical yarn consumption and practical yarn requirement are not always the same.
Factor
Why it matters
Actual warp crimp
Changes the real yarn length consumed in the fabric body.
Loom waste
Extra yarn is required during weaving, tying, starting and ending.
Beam gaiting waste
Warp preparation and loom setting may consume additional yarn.
Fringe trimming
The final towel may lose some yarn during trimming or finishing.
Sizing material
Sizing may increase grey fabric weight before desizing or washing.
Moisture regain
Measured yarn and fabric weight may vary with atmospheric moisture.
Yarn count variation
Actual yarn may differ slightly from the nominal tex value.
Finishing shrinkage
Final dimensions and GSM may change after washing and finishing.
Therefore, for production costing, this theoretical value should be adjusted using mill experience and actual fabric measurements. The formula gives the logic, but the mill data gives the practical correction.
13. Key Learning
The ground warp weight of a terry towel depends on four main things: the length of the towel, the number of ground warp ends, the yarn count in tex and the warp crimp or take-up. The basic logic is simple:
The most important point is to handle the units carefully. Since tex is based on grams per 1000 metres and towel length is often given in centimetres, the conversion factor must be applied properly. A calculation may look simple, but a small unit error can produce a very large difference in yarn consumption and costing.
For a textile student, merchandiser or production planner, this calculation gives a useful foundation for understanding towel costing and yarn consumption. The ground warp is only one part of the towel. To calculate the complete towel weight, one must also calculate the pile warp and weft weights separately.
In the next part, we can calculate the pile warp weight, which is usually the most important contributor to the weight, feel, absorbency and bulk of a terry towel.
Related Reading on Textile Calculations, Yarn Count and Fabric Weight
Hutex. Terry Towel: Terry Weaving. Available at: https://hutex.co.kr/wp-content/uploads/2023/06/Terry_Towel.pdf
ScienceDirect Topics. Pile Warp - An Overview. Available at: https://www.sciencedirect.com/topics/engineering/pile-warp
Textile School. Terry Towels: Fabrics That Can Absorb Large Amounts of Water. Available at: https://www.textileschool.com/3211/terry-towels-fabrics-that-can-absorb-large-amounts-of-water/
Resil Chemicals. Technical Tuesday: Terry Towel. Available at: https://resiltextiles.com/wp-content/uploads/simple-file-list/Technical-Tuesday/2014/TT-Terry-Towel.pdf
ResearchGate. An Investigation into the Parameters of Terry Fabrics Regarding the Production. Available at: https://www.researchgate.net/publication/293131432_An_investigation_into_the_parameters_of_terry_fabrics_regarding_the_production
General Disclaimer
This article is intended for educational understanding of terry towel yarn consumption calculations. The numerical values used here are illustrative and should not be treated as universal production standards. Actual mill calculations may vary depending on yarn count variation, loom settings, pile ratio, warp and weft crimp, sizing, wastage, finishing shrinkage, moisture regain and the specific construction of the towel.
For commercial costing, production planning or quality control, the calculation should be verified with actual fabric samples, mill records and approved technical specifications.
The warp sheet normally contracts from 2 to 15 percent in width from reed to the cloth. This contraction is due to interlacement of warp and weft.
This contraction need to be avoided temporarily because otherwise:
1. There is a possiblity of damage to the warp ends near the selvedge due to abrasion with reed dents.
2. There is a possibility of reed dents getting themselves distorted.
3. There will always be a tension in the beat-up zone.
The temples are used to hold fast the width of the woven cloth as equal to as possible to the width of the warp.
Types of Temples
1. Ring Temples
In ring temples the rings are usually at an angle of 12 deg to 21 deg and the angle reduces in steps of 3 deg towards the centre of the cloth.
As a thumb rule the lenght of the pints should be about one and a half times to two times the cloth thickness. The pins exert their pull on the warp.
Also the greater the tube diameter the greater the wrap of the cloth on the temple tube.
The length of the temple tube depends upon the cloth width. A rule of thumb is one ring for 10 cm fabric.
For delicate cloth, pinned rings are used only in the cloth selvedge zone. The inner rings are substituted by textured surface rubber, plastic or bras rings.
2. Roller Temples
The roller temples usually have two rollers supported at both ends which guide the fabric in the warp directions by means of raised points. The rollers are usually of steel and are covered with rubber or plastics.
Ring and roller temples hold the fabric in the selvedge zones only and stretches the fabric outwards.
These temples have the disadvantage that the pressure of the beat-up of the reed against the fabric is transmitted to the next guiding point of the fabric, which is the breast beam. This point is several inches from the fell of the cloth and therefore extensive tension is required for the beat-up. The tension causes breakages of the warp yarns.
Another disadvantage of this group of temples is the presence of different lengths of the fabric from the fell of the cloth to the breast beam, caused by the looping of the fabric around the temple cylinders. This causes a deformation of the straightness of the weft and therefore of the design. In extreme cases it creates waviness of the selvedges.
3. Full Width Temples
The other group consists of full-width temples.
The full width temples hold the fabric across its full width under uniform tension. The advantages of using full width temples are that weaving can be done at lower warp tension. One more advantage is less stress for the ends, resulting in less ends breakage.There are no temple ring marks. A higher weft density is possible. There is a straight weft insertion over the whole width. Also less maintenance is required.
However the full-width temples cannot avoid a contraction of the fabrics weft wise. By reason of this contraction, the warp ends in the selvedges do not pass at straight angle through the weaving reed. This causes extensive friction between yarn and reed and can lead yarn breakages.
Silk denim, developed in India by CSTRI seems to have a lot of potential. With the market of denim in India growing by leaps and bounds, denim silk will give that niche in the minds of customer that can make a company profitable.
There are however lots of challenges that denim jeans made of silk will face in the market. First there is a problem/question of its production viability. Then there will be a question of its wearing performace.
Then of course care of this fabric will be a major challange. Even if this is overcome, cost will be a deciding factor in this recession hit economy. And of course, there will be always a challenge to fight from the spurious fabrics.
Lets talk about parameters. The warp in silk is made from 20/22 denier 6 and 12 ply organzine twisted(Organzine is a thread made by giving the raw-silk thread a preliminary twist in one direction and then twisting many of these threads together in the opposite direction at the rate of about 4 turns/cm ) mulberry silk fiber or eri silk of 2/60s, 2/80s and 2/120s is used. In weft 6 and 12 ply tram twisted (Tram is made by twisting in only one direction two or more raw-silk threads, with 8 to 12 turns/cm). Mulberry silk and eri silk of 2/60s, 2/80s and 2/12s greige yarn is used. All this is OK, the only concern is the avaliability of these fibers. It is then made on rapier looms with 44" width and 3/1 twill weighing 100-300 gsm. The only questions are the production challenges while handling such delicate fibers.
Functionally, twill weaves in silk are prone to slippage of yarn, particulary if two different fibers are used in warp and weft.which might affect the tear strength and seam slippage.
Also the faded look of denim comes from Indigo dye, which is a vat dye, and which is faded differentially as the denim is washed. In Silk Denim, Indigo colored acid dyes are used, which dont fade at all. This will maintain the consistency of shade for years, but surely will take away the joy of fading that is obtained with cotton denim.
Then of course there are issues for the care and maintainenace of these fabrics. These must be dry cleaned and taken care of properly. Also eri silk denim will behave like wool and more suitable in winter.
The biggest issue of all is the cost. Due to limited supply, the quality silk denim would be much much costlier than the normal indigo cotton denim.
Thus all the discussion above will point out to the a very specific market for silk denims. Target audience would be upper class young females in the age group of 25-40. It would be better if the bottoms were to sold with the matching printed or plain silk tops. It would be further beneficial for a marketer if the word 'denim' is taken out of this fabric, as customer will erroneously compare the properties of indigo denim with this fabric. Some surface emballishments can be done like printing or embroidery on these garments.
The Banaras Bunkar Samiti, an organisation of Banarasi handloom weavers and eight other organisations are making efforts to receive the IPR to the silk brocade and Banarasi saree. The GI acts as a certification that the product possesses certain qualities, or enjoys a certain reputation, due to its geographical origin.
Banana Shirts
Weavers of Anakaputhur, about 20 kms from Chennai have brought in this new product with technical support from the National Research Centre for Banana ( NRCB) Trichi. At Rs. 450 a piece, such shirts keep the body cool. Banana fiber after processing, is odorless and can be dyed in any color. The shirts don't shrink, fade and keep the stiffness even without starch. However, a blend of 60% cotton with this fiber given maximum durability. Banana fiber is also cost effective with 40/- a kg and can yield two 100% banana shirts. Other suppliers of banana fiber can be found here.
The following is a list of 16 things to ensure while making an industrial apparel pattern manually:
All the features of the style
Pattern count ( Number of pattern sections) according to the style
Seam allowance based on style
Type of fixtures required on sewing machine in the manufacturing
Final drafting measurements based on the shrinkage value ( both warp and weft way) for garmens which are subject to further treatment such as washing or dyeing.
Grading the pattern based on the size specification.
Marking the grain lines by an arrow head.
Provide guide notcher for precision assembly, punch holes for positioning of components and darts.
Use of white hard board paper for drafting.
Use of black color for drawing the original draft line.
Identify the pattern by its style number, customer's name, date of preparation and mention of its status as "sample"
On preparation of the sample garment, place all the pattern sections in a paper bag mentioning pattern count, style number, customer's name
On receipt of customer's feed back on sample garment effect the changes, if any, by manipulating the draft with Blue color and endorse with signature and date.
On approval from the production manager, change the status of patterns from "sample" to "production"
On finalisation of drafting , prepare "ready patterns" on two tone paper for small components meant for cutting section, sewing section and for monitoring purpose.
In order to prevent curling and chipping of the edges of the pattern section, protect the edges by metal foils.
Bright full colors are obtained with very good fastness properties.
These are used for printing backgrounds so that the foreground becomes prominent. Hence these are suitable where large areas of ground need to be colored.
Rapid dyes are mixed with water and boiled with caustic soda and a gum paste. A receipe for rapid dyes is given here.
The shades in rapid dyes are unpredictable since the color that is mixed is different from the final color.
True colors emerge only after the fabric has been printed and washed in a mild sulphuric acid solution.
Also these dyes should be used on the same day.
Some colors such as pure blacks are extremely sensitive to weather. Similarly red colors in rapid is vibrant in summers and mediocre in winter
Rayon has a low wet strength. Thus the fabric may shrink or stretch when wet. Dry cleaning is recommended. When hand washing, do not wring, use towel to take out moisture and dry flat.
Some dyes used on rayon migrate to the surface, when moisture contacts them, they form a "ring" which are difficult to remove. Thus it makes sense to protect the garment from moisture.
Also when pressing, avoid spitting by steam irons. Press on wrong side or use a press cloth to protect shine or iron imprints.
Rayon fabrics stretches during regular use or drycleaning. This tendency is more common in fitted garments.
In full bias skirts or dresses, uneven hemlines may appear in rayon crepe fabrics in damp climates. This happens because rayon is less stable when wet.
Yellowing in the rayon fabrics may occur due to oxidation of starch present in the fabric. This problem is noticeable in white fabrics. Wet cleaning, accompanied by bleaching will correct the problem. However this treatment can cause additional damage due to shrinkage and limpness.
While looking for the definition of gad, rekh and datta blocks, I came across the following in website of Indianetzone" The gad, rekh and datta are three types of blocks that are distinguishable by their different styles of carving. The gad is carved in intaglio and is engaged to print large background figures, while rekh and datta are carved in complete relief. Rekh blocks also mark the outlines of the motif and are often used in conjunction with gad blocks, the rekh then forming the fine elaborate lines within the impression made by the gad block. Datta is carved in bold relief and complements the designs of both the gad and rekh blocks. Each of these blocks is used separately or together to produce endless design variations."
Now some terms were not clear to me. For example what is "....carved in intaglio.." means, on searching I found this website of carving patterns giving a beautiful definition and explanation, basically carving intaglio is "Intaglio carving uses the reverse technique to produce the image effect. Here, the main image is the negative areas of the work, instead of the background being carved away it is the design the you remove."
And what is " carved in.. relief" ? For this Wikipedia came to rescue: "Relief carving can be described as "carving pictures in wood". The process of relief carving involves removing wood from a flat wood panel in such a way that an object appears to rise out of the wood"
Small Parts Major Defects 1. Rib Knit set crooked-off, grain holes or runs in knit. 2. Misshaped collars and cuffs 3. Misshaped Tabs Zippers Major Defects 1. Zipper more than 3/8" from bottom. 2. Poorly set zipper causing closure problems. 3.Twisting of the zipper caused by the top stitching of the zipper front. 4. Poorly set zipper causing waviness in the front. Minor Defects 1. Twisting of the zipper front caused by the top stitching of the zipper front. 2. Setting front ( or facing ) too close to the teeth so that the slider cannot properly function. Button/buttonholes Major Defects 1. Button and button holes not set in proper positions or out of alignment. 2. Uncut buttonholes/ missing button/ snap fasteners/ buckles/ zippers etc. 3. Not set in proper position 4. Defective or rusted hardware 5. Hardware not according to the specification in size, color, shape. 6. Snap coming off tacks ( Bartacks) 7. Omitted or misplaced or rivet not servicing its intended purpose/improper length. Minor Defects 1. Too few stitches in the buttonhole. 2. Buttonhole too large or too small for the button. 3. Button not securely sewn.
Silk should be dry-cleaned, in most of the cases. Whenever in doubt, dryclean it.
It should not be machine washed at all.
Silk Shrinks when washed in water. It doesn’t itself shrink. It is the way the individual fibers are twisted together than causes the silk to shrink. Highly twisted yarns and loose weave cause shrinking when water releases twisting energy in the fibers.
Water also affects the texture and sheen of the fabric. Thus the firmness and color of the fabric is also affected by water.
When hand washing do it in this way:
Always wash silk in soft water. Add a pinch of Borax or ammonia, if the water is hard.
1. Put the silk in a tub full of lukewarm water and mild soap like Ezee.
2. Rub the silk fabric for a few minutes in the solution and drain.
3. Rinse in clear cool water until all the soap is gone.
4. Fill the tub again and put about a quarter cup of white vinegar.
Vinegar neutralizes any remaining soap and allows it to rinse out completely restoring the fabric’s natural sheen. It also helps preventing any damage from the alkali present in the soap.
5. Give the fabric a final rinse in clear, cool water to restore the vinegar smell.
6. Roll up in a towel to remove moisture then dry flat on a towel. Never wring it.
7. Avoid soaking silk as this may fade the dye.
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.
Please test this method on a small part of the garment before commencing the full-fledged washing.
Treating Stains
1. Use a capful of hydrogen peroxide and a few drops of ammonia added to the wash.
2. For recent perspiration stain dab a tablespoon of ammonia dissolved in half cup of water. Older perspiration can be removed with a vinegar solution. Unfortunately, perspiration stains on silk may not be completely removable.
Pressing
1. Silk should be pressed when damp never when completely dry.
2. Turn the item inside out and iron on the reverse side of the fabric.
3. Use a low setting and don’t use steam as it will leave watermarks.
Storage
1. Keep silk in a cotton pillowcase or other material that can breathe.
2. Avoid plastic which traps moisture and can cause yellowing and mildew
3. Use naphthalene balls to keep the bugs away from silk.
4. Avoid direct contact with wood
5. Wrap zari sarees in cotton cloth to avoid discoloring of zari.
General Care Instructions
1. Keep it away from heat or direct sunlight, it will yellow the fiber.
Linen is the strongest of the vegetable fibers and has 2 to 3 times the strength of cotton. Linen table cloths and napkins have been handed down generation to generation.
Linen is Smoother
Not only is the linen fiber strong, it is smooth, making the finished fabric lint free. Fine china, silver and candles are enhanced by the luster of linen which only gets softer and finer the more it is washed.
Wrinkles more easily than Cotton
Linen does wrinkle easily but also presses easily.However, constant creasing in the same place in sharp folds will tend to break the linen threads. This wear can show up in collars, hems, and any area that is iron creased during the laundering.
Not As Elastic
Linen has poor elasticity and does not spring back readily.
Touch is Different
Cotton is softer, fluffier, and warm to the touch. Linen is smooth, heavy and flowing, and feels cool because it absorbs moisture more readily than cotton.
Cotton is Easier to Rip
Since flax fibres are longer than cotton fibres, cotton is easier to rip.
Pure Linen Vs.Linen/Cotton Blend
Cotton/linen - a little softer, and won't wrinkle as much as pure linen.
For shirts, cotton/linen is great
Pure linen is not bad, necessarily, but it is stiffer and also hard to find in really light weights. The thickness of most pure linen does not lend itself to dress shirtings well.
Tendering in the fabric takes place because sulphur is converted into sulphuric acid after oxidation which is harmful for the cellulosic fibers. This defect can occur on account of not proper washing of the fabric after dyeing which results in retaining of sulphuric acid on the cloth.
2. Uneven Dyeing and Oxidation Marks
This may occur due to:
a. Lower strength of sodium sulphide
b. Using improper amount of sodium sulphide.
c. Sodium sulphide does not wash off fully after washing.
d. Variation in temperature.
e. If colors are not dissolved properly, or colors are not of good quality
f. If the chemical used for oxidation is not of good quality
g. Fabrics are not worked upon properly at the time of dyeing.
3. Bronziness
This defect normally occurs in heavy shades. Given below are the reasons:
1. More time gap between dyeing and washing
2. Using more of less strength sodium sulphide
3. Using more salt.
4. Oxidiser doesn't get washed off properly during washing
5. Sodium sulphide doesn't get washed off properly during washing.
6. More presence of iron and copper ions in water.
4. Poor colorfastness to rubbing
It depends upon:
a. type of color b. Lower strength of sodium sulphide c. Poor absorbency of the fabric d. Fabric is not washed properly e. The quality of soap used for washing is not proper f. Dyeing bath made of iron instead of steel g. Frequent addition of colors and chemicals h. Using Cationic finishing agent in finishing also lowers the colorfastness to rubbing i. Improper color solution, Improper material to liquor ratio etc.
5. Roughness in Fabric
1. Using more amount of sodium sulphide that doesn't get washed off during washing. 2. Heavier shade 3. Improper washing 4. Not using anionic softening agent in finishing 5. Not using wetting agent.
a. Take 200 gms of Myrobalan powder for 1 kg of fabric
b. Make a smooth paste with water, without any lumps
c. Add water till it becomes 5 liters.
d. Mix well
e. Soak the fabric in this
f. Work the fabric in this solution at room temperature for 15 to 20 minutes.
g. Squeeze the material and dry it in shade.
h. When dried, remove the unfixed material by striking it against wall.
2. Preparation of Thickening Agent
Using Tamarind Seed Powder
a. Add 100 gms of Tamarind seed powder in 1 liter of boiling wter.Sprinkle the powder in the boiling water stirring to avoid lumps.
b. Cook and mix till a fine paste is ready, cool it and filter the contents.
c. Remember that this paste is stable only for 2 to 3 days.
Or
Take Bhagvathi gum, add 30 to 50 gms of powder for 1 liter of water. It is also soluble in cold water.
This paste has better stability
Avoid Gum Arabic.
3. Mordanting the Solution with Mineral Salts
Take the mineral salts according to the following formula:
x parts of mineral salts 15 to 20% boiling water 70% thickening agent to make it 100%.
The following are the general guidelines for getting the dark shades.
Alum= 10%, available by the name of Fitkari Potassium Dichromate= 5%, available as Lal Kashish Copper Sulphate= 10%, available by the name of mor Thuth Ferrous Sulphate= 1 to 5%, available by the name of Hira Kashish Iron Solution = 50%
Iron solution is made by the following procedure:
a. Take 2 kg of Iron Pieces, 1 to 1.5 kg of Jaggery and add 20 liters of water.
b. Keep in a plastic container for 3-4 weeks
Tin Chloride= 0.5 to 1.0 %
The Procedure for making the paste is:
a. Ground the mineral salt into powder form. b. Add water and boil. c. When completely dissolved, add the thickening agent.
The paste is ready for the printing process
4. Printing
Now Print the fabric using blocks. Dry and wash as follows:
5. Washing
When washing in river keep the printed portion face down so that it touches water. Wash for about 5 to 10 minutes, printed portion is not touched. Care should be taken that printed portion should not touch the unprinted portion.
After washing, dry in flat on the ground. Dont hang. Now the fabric is ready for developing.
6. Developing of Color
Fabric is developed using traditional material. For yellow ranges Pomegranate rind ( Anar ka Chilka) or Forest Yellow (Amba Haldi) 50% or Moduga flowers ( Desuda phool) are taken. For Pinks to reds maroons Alizarin(0.5% with 10-20% Dhavdi flowers added to dye bath), Mnajistha(25-50%) is taken, for grey ranges: Rathanjoth(30% to 50%), Ferrous Sulphate is taken, for brown range: catechu ( Katha) and its componets are taken.
Powder the dye and mix and boil with water for 3-4 boils. Filter it. Make a dye bath with material to Liquor ratio of 1:20 at 50 deg C. Add the solution in it. Enter the fabric ( already mordanted ) in it. Work well and raise the temperature to boil. Dye for 30-40 minutes. Wash and soap. Dry in shade.
Some very good definitions of Major, Minor and Critical Defects can be found Here.
Major, Minor and critical Defects are the part of classification given to the flaws while inspecting the fabrics or garments.The classification depends upon the severity of the defect and forms a basis of acceptance or rejection of the lot.
Consideration in classifiying the defects as major or minor is taken on the basis of the affect on saleability of the garment, location of the defect and conspicuousness of the defect.
In this document , the location of the defect( the zone) is shown in various garments which make a defect serious or insignificant. There is also a comprihensive list of the critical defects. An analysis of Fabric defects according to their severity as major or minor can be found in this document.
This document is in the form of a contract but it deals brilliantly with all the quality issues including the defects.
The Following is an indicative list that can be followed to ascertain if a defect is a minor or a major defect in a garment:
Seam and Stitching
Major Defects:
1. Stitch Requirements a. Inside 8-10 SPI b. topstitch 8.9 SPI c. Other requirement as specified
2. Seam grain 3. Thread breaks 4. Feed damage 5. Excessive amount on skip stitches ( 2 or more) 6. Pleat in seam (other than required by style) 7. Poorly repaired seams 8. Broken stitches two or more if conspicuous. 9. Conspicuous needle damage hole. 10. Open seam raw edges or frayed materials 11. Uneven stitch density, staggered stitch 12. Too many stitches giving rise to jumping and rupture of fabrics and few to grinning and weak seams 13. Wrong stitch density 14. Run off stitch. 15. Omitted sewing i.e. top stitch, button hole, snap, velcro etc. 16. Serious, uneven edge of seam ie bottom of waistband, right to left seam matching, pocket mouth etc. 17. Double stitching and poorly repairs affecting the appearance and service. 18. Improperly formed stitch or loose tension of stitches causing loops on surface easily pulled out. 19. Stitch tension which breaks under normal stress. 20. Wrong colour match thread 21. Napped fabric-cut or sewing in the wrong direction or mixed in the garment causing shading. 22. Wrong seam type or stitch type used 23. Blind stitching showing on the face side. 24. Reverse garment parts. 25. Extraneous part caught in seam. 26. Mismatched seam. 27. Mismatched checks or stripes 28. Any twisted, loosen, tighten, puckered or pleated or overlapped seam. 29. Irregular or incorrect shape of sewing line "run-offs" 30. Incorrect or uneven width of inlay i.e. seams burst open, raw edges show slippage of weave threads.
Cotton has the property of swelling in water and this effects shrinking when drying. Also the mechanical stresses, strain and tension, during spinning and weaving etc., when released causes the fabric to shrink.
The cotton fabric, when put in water, swelling occurs and rearrangement of internal forces takes place. The fibres will become free from tensionless state. These are the resons for shrinkage.
In case of a fabric, the warp yarns are under much strain due to interlacement than the weft yarns. The warp yarn shrinkage will be more than weft.
to overcome this, the fabric is extended in widthwise to some extent in the stenter machine during the finishing process. Then it is subjected to preshrink process.
1. Mean Length: Numerical Average length of fibres of given population of fibre.
2. Upper Quartile: Length for which 75% of all observed values are lower or 25% higher by weight or number
3. Modal Length: The most frequently occuring length of fiber.
4. Median Length: Length Below and above which 50% of fibres lie.
5. Half Fall Value: The fiber length higher than modal length having half the modal frequency by wt. (Group length longer than mode with frequency equal to 1/2 of mode.)
6. Effective Length: Upper quartile of numerical length distribution from which some of the shortest fibers, having length less than half of effective length are cutailed or eliminated.
7. short fiber %: It is the % of fibers having length less than 1/2 of the effective length value.
8. Uniformity Ratio: Ratio of 50% span length to 2.5 % span length.
9. Span Length: It is the distance that can be spanned by specified percentage of fibers in a test beard.
10. Irregularity: Percentage by weight fo fibers in a sample which are shorter than 3/4th of the mode.
11. Dispersion %: inter quartile range expressed as % of effective length.
How to Determine the Color Fastness of Textile material to Dry Cleaning
Technical Specifications:
Apparatus:
1.To determine colorfastness to drycleaning a suitable mechanical device consisting of water bath containing a rotatable shaft which supports, radially, glass or stainless steel containers ( 75+-5mm diameter x 125+-10mm high) of approximately 550+-50 ml. capacity, being 45+-10mm high from the centre of the shaft should be used. The Shaft/container assembly is rotated at a speed of 40+-2 rev per minutes.The temperature of the water bath is thermostatically controlled to maintain the test solvent at 30 deg +-2 celcius.
2. Stainless stell disc of 30+-2mm x 3+-0.5mm, smooth and free from rough edges of mass 20+-2 gm.
3. Undyed cotton twill cloth of unit area 270+-70 gsm, free from finishing and cut into samples of size 12 cm x 12 cm
4. Grey scale for evaluating change in color and staining.
5. Glass tubes of diameter 25 mm
Preparation of the Specimen
For a fabric sample, take a specimen of size 10cm x 4cm from the sample representing the lot.
If the material to be tested is sewing thread, make a wick of parallel length 10 cm long and about 0.5 cm in diameter, tied near both ends.
Procedure
Prepare a bag with inside dimension of 10cm x 10 cm using the undyed cotton twill cloth by sewing together two squares of this cloth around three sides.
Place the specimen and 12 stell discs inside the bag and close the bag.
Place the bag in the container and add 200 ml of Perchloroethylene or any other suitable solvent at 30 +- 2 deg C
Fix the container in the mechanical device maintained at 30+-2 deg C and run the machine for 30 minutes.
Remove the bag from the container, withdraw the specimen and dry the specimen in air at a temperature not exceeding 60+-5 deg C.
Evaluate the change in color of the tested test specimen with grey scale, after attaining normal moisture content.
Filter the solvent remaining in the container through filter paper and compare the color of the filtered solvent with that of unused solvent in the glass tube placed in from the white card using transmitted light by means of grey scale for assessing staining.
In case of doubt in the color fastness rating as assessed by an observer, the assessment should be done by at least three observers and the overall average rating should be reported.
Report
Report the numerical rating for change in color of the test specimen and the numerical rating for staining of the solvent. Also report the solvent used for the test.
Listing Defect in Vat Dyeing and the Precautions to Prevent the Defect
Listing is the variation in color of centre of the fabric with the selvedge. Some of the reasons for this defect are:
1. Improper batching. 2. Non Uniformity in the selvedge 3. Redyeing of the fabric 4. Foam on the two sides of the jigger. 5. Slippage of the fabric from the roller during dyeing. 6. Shortcomings in the machine such as malfunctioning of guide roll, expander roller or improper squeezing. 7. Improper filteration of the colors, improper circlation of the liquor during dyeing. Difference in temperature of liquor in the centre and at the ends. 8. Mixing of colors which are not properly compatible. 9. Improper singeing
The remedies are:
1. There should not be any mechanical fault in the machine. 2. Take proper care during dyeing, like filter the color solution before using, ensure that all the controlling instrument ( temperature, time) work properly. Circulate the liquor continuously during dyeing. 3. If some shade is not coming out proper, dye with a slighly heavy shade without taking out the earlier color. 4. Join the fabrics of the same width while making a lot.
Colour Fastness to Rubbing: Why Fabrics Sometimes Leave Colour on Other Surfaces
A common complaint in textiles is: “The fabric is giving colour.”
Sometimes the colour comes out during washing, sometimes during perspiration, and sometimes simply by rubbing.
A dark saree rubbing against a light blouse, a printed dupatta staining the neck area, denim leaving blue marks on a bag,
or upholstery fabric staining clothing are all examples of poor colour fastness to rubbing.
The Indian Standard IS 766:1988 gives a method for determining the
colour fastness of textile materials to rubbing. It applies to textile materials in different forms,
including fabrics, yarns, textile floor coverings and pile fabrics. The test is carried out in two ways:
dry rubbing and wet rubbing.
Visual 1: Colour fastness to rubbing test overview — fabric specimen, rubbing cloth, rubbing finger and stain assessment. AI generated- may have mistakes in details
What is colour fastness to rubbing?
Colour fastness to rubbing means the resistance of a dyed or printed textile to transfer its colour to another surface
when rubbed.
In simple language, it answers one practical question:
If this fabric rubs against another fabric, skin, furniture, or garment part, will it stain it?
This is especially important in deep shades such as black, navy, maroon, red, indigo, bottle green and dark brown.
It is also important in printed textiles, pigment prints, denim, sarees, dress materials, upholstery, carpets and pile fabrics.
Why rubbing fastness matters
A fabric may look attractive in the store, but if it stains another garment during use, the customer experiences it as a
quality failure. Colour fastness depends not only on the nature and depth of the dye, but also on fibre type and the dyeing
or printing method used. The same colouring matter may behave differently on different fibres or when applied by different
processes.
For merchandisers, buyers and quality inspectors, this means one important thing:
Colour fastness cannot be assumed only from appearance. It has to be tested.
Principle of the rubbing fastness test
In this test, the textile specimen is rubbed with a standard white cotton rubbing cloth. After rubbing, the staining on the
rubbing cloth is assessed using a grey scale for staining. Two tests are made:
one using a dry rubbing cloth and another using a wet rubbing cloth.
The idea is very practical. If colour transfers to the white rubbing cloth, the fabric has lower rubbing fastness.
If very little colour transfers, the fabric has better rubbing fastness.
Apparatus used
The test requires a rubbing testing device. For pile fabrics, including textile floor coverings, a larger rubbing finger is used:
3.2 cm diameter, with a downward force of 22 N, moving along a
10 cm track.
For all other textiles, a 1.6 cm diameter rubbing finger is used with a downward force of
9 N, again moving along a 10 cm track.
The rubbing cloth is a standard cotton cloth: desized, bleached, without finish, cut into
5 cm × 5 cm squares. A grey scale for evaluating staining is then used to rate the amount of colour transferred.
Visual 2: Dry rubbing and wet rubbing comparison — showing how the rubbing cloth is used in both test conditions. AI generated- May have mistakes in details.
Preparation of the specimen
For fabrics and textile floor coverings, the specimen should be at least 14 cm × 5 cm.
Separate specimens are taken for dry rubbing and wet rubbing.
One specimen is taken with its long direction parallel to the warp, or direction of manufacture, and another parallel to the
weft, or at right angles to the direction of manufacture.
This is important because rubbing behaviour may differ in warp and weft directions. In woven fabrics, yarn structure,
surface hairiness, floats, finishing and print placement may not be identical in both directions.
For yarn or thread, it may be knitted or woven into fabric, or arranged as parallel strands on a cardboard rectangle to prepare
the test specimen.
Dry rubbing test
In the dry rubbing test, a dry rubbing cloth is fixed over the rubbing finger of the testing device. The specimen is rubbed
in a straight line along a 10 cm track, 10 times to and fro in 10 seconds.
The force applied depends on the type of textile being tested:
22 N for pile fabrics
9 N for other textiles
After rubbing, the cotton cloth is examined for staining. Loose dyed fibres pulled out during rubbing should not be mistaken
for actual dye staining. The assessment should consider colouration due to staining by dyestuff.
Wet rubbing test
The wet rubbing test is similar, but the rubbing cloth is first wetted with water. The cloth should have about
100% water take-up. After rubbing, the cloth is dried at room temperature and then assessed for staining.
Wet rubbing is often more severe than dry rubbing. Many fabrics that pass dry rubbing may show lower performance in wet rubbing,
especially dark shades, pigment prints, indigo-dyed fabrics and poorly after-treated dyed materials.
Multicoloured fabrics
When testing multicoloured textiles, the specimen should be positioned so that all colours in the design are rubbed during
the test. If the colour areas are large enough, separate specimens may be taken and each colour assessed separately.
This point is very useful for printed sarees, dress materials, dupattas and furnishing fabrics. A single rubbing result may not
represent the whole design if one colour is fast and another colour is weak.
Rating and reporting
The staining of the rubbing cotton cloth is assessed using the grey scale for staining. The report should give numerical ratings
separately for dry staining and wet staining, and for each direction of manufacture.
Test condition
Direction
Rating
Dry rubbing
Warp direction
4–5
Dry rubbing
Weft direction
4
Wet rubbing
Warp direction
3
Wet rubbing
Weft direction
2–3
In general interpretation, a higher grey scale rating indicates less staining and better fastness, while a lower rating indicates
more staining and poorer fastness.
Visual 3: Grey scale rating interpretation — higher rating means less staining and better rubbing fastness. AI generated- may have mistakes in details.
Special problem in pile fabrics
Pile fabrics can create a difficulty known as haloing, where heavier staining appears around the circumference
of the stained area. The larger 3.2 cm rubbing finger can reduce haloing in many pile fabrics, although
assessment may still be difficult for high-pile fabrics.
This is relevant for carpets, velvets, towels, blankets and certain upholstery fabrics. Their raised surface behaves differently
from flat woven or knitted fabrics.
Practical meaning for textile buyers and merchandisers
For a buyer, rubbing fastness is not just a laboratory number. It has direct customer implications.
A dark saree with poor rubbing fastness can stain a blouse. A printed dupatta can stain the neck or kurta.
A dark upholstery fabric can stain light garments. A poor pigment print can leave colour on hands.
Denim with poor rubbing fastness can stain bags, shoes and car seats.
Therefore, rubbing fastness should be checked carefully in:
Dark dyed fabrics
Indigo and denim-like fabrics
Pigment printed fabrics
Sarees with strong contrast colours
Upholstery and home textile fabrics
Pile fabrics and carpets
Fabrics expected to rub against skin or lighter garments
Common mistakes in understanding rubbing fastness
One mistake is to think that only washing fastness matters. A fabric may not bleed badly in washing but may still stain during rubbing.
Another mistake is to look only at dry rubbing. Wet rubbing is equally important because garments are often used in humid conditions,
during perspiration, or after partial wetting.
A third mistake is to test only one part of a multicoloured fabric. In printed textiles, each colour may behave differently.
A fourth mistake is to ignore direction. Warp-way and weft-way rubbing results may differ, especially in fabrics with surface texture,
floats or pile.
Knowledge nugget
Rubbing fastness is a surface-performance test. It tells us how well the colour is held on the textile surface when mechanical friction is applied.
This is why rubbing fastness is often a problem in dark shades, pigment prints and fabrics where dye fixation, washing-off or finishing
has not been properly controlled.
Conclusion
The rubbing fastness test is one of the most practical colour fastness tests in textiles. It simulates a real-life action:
one surface rubbing against another.
IS 766:1988 standardizes this test by defining the specimen size, rubbing cloth, rubbing force, rubbing distance, number of strokes,
dry and wet conditions, and method of assessment.
For students, it teaches how laboratory testing connects to consumer use. For merchandisers and buyers, it gives a simple but powerful
quality checkpoint. And for manufacturers, it reminds us that colour is not only about beauty — it is also about durability in actual use.
Suggested visuals to accompany this article
Colour Fastness to Rubbing Test Overview:
A labelled diagram showing fabric specimen, white rubbing cloth, rubbing finger, rubbing direction and grey scale assessment.
Dry vs Wet Rubbing Fastness:
A comparison visual showing dry rubbing cloth and wetted rubbing cloth, with examples of lighter and heavier staining.
Grey Scale Interpretation Chart:
A simple educational chart explaining that rating 5 means no or negligible staining, while rating 1 means heavy staining.
Source
Based on IS 766:1988, Indian Standard method for determination of colour fastness of textile materials to rubbing.
General disclaimer
This article is written for educational and general understanding purposes only. The explanations simplify the testing method for
students, merchandisers and textile professionals. For official testing, certification, dispute resolution, legal compliance or
commercial acceptance, the original relevant Indian Standard and accredited laboratory procedures should be referred to.
Polyurethane is produced by action of butanediol and hexamethylene diisocyanate.
The polyurethane thus formed has rubber like properties. It gives an elastomeric fibre, which displays elasticity associated with natural rubber and hence can be stretched several times its original length and on releasing the stretching loads it will snap back quickly to recover its original length almost completely. Therefore polyurethane fibres are called snap back or elastomeric fibres.
Different Steps in Fiber Manufacture
Prepolymer Production:
The soft segments of the final polymer are formed in this step. The segments are the source of amorphous regions which permit unfolding of the molecular chains leading to the extension of the fibre under tensile stresses. These segments are made by normal condensation polymerisation techniques. These segments have hydroxy groups at the end.
Reaction Between prepolymers and Diisocyanate
The first prepolymer is reacted with excess of diisocyanate to form urethane groups in the molecular chains.
Segmented polyurethane production
In this step the hard segment is created by chain extension in which second prepolymer is treated with glycols or diamines.
Spinning
When the final polymer contain essentially linear macromolecules then it is dissolved in the solvent ( eg. DMF- Dimethyl Formamide) and extruded through spinnerettes into a coagulating bath ( water) as in wet spinning or into an atmosphere to remove the solvent as in dry spinning.
Properties
Strength: 0.55-1.0 gpd
Extension at Break: 520-610 %
Specific Gravity: 1.20-1.25
Set % at 600% stretch: 70%
Moisture Regain: 0.8-1.2
It is a thermoplastic fibres which sticks at 170 deg C and melts at 230 deg C
It has an excellent resistance to sunlight
It is resistant to insects and microorganisms.
It is resistant to common solvents such as dry cleaning solvents and saturated hydrocarbons.
Chemical Properties
It has good resistance to cold dilute Acids, Hot concentrated acids slightly yellow it.
It has a good resistance to weak and cold alkalies. It has good resistance to cosmetic oils and lotions. Chlorites and hypochlorites attack the fibre.
When heated the fibres fuse and do not shrink from the flame. They burn and produce soft fluffy black ash.
Defect: Colors are not fast to washing, Abrasion;Staining in the fabric when transporting from place to the other, water marks on the fabric
Remedy : Wash the fabric with soap and soda ash at right temperature. Adding sequestering agent will yield good results. Treating with Ammonia will also give good results.
Defects in the fabric due to Printing- Need to take out full color
Remedy: Treat the dyed fabric with Sodium Hydrosuphite with 5-10 gm Sodium Hydrosulphite at 75 deg C for 30-45 minutes. Add 5-7 gms Caustic Soda for even removal of colors. The color becomes light yellow or brown after removal. Wash it thoroughly with soap.
The color can also be removed by solution of Sodium Hypochlorite. Treat the fabric with a sodium hypochlorite solution ( 3-5 gms Chlorine) for 20-30 minutes. Keep the pH between 9-10. The fabric is treated with Acetic acid after removal of color to remove chlorine and to neutralise the fabric.
The fabric can be redyed after removal of color
Defect: Bleeding in colors during washing, abrasion
Remedy: Boil the fabric with caustic, Treat the fabric with Hydrogen Peroxide ( 5-10 gpl, 60-70 deg C) to make the color fast.
Defect: The fabric has been dyed in darker shade, uneven dyeing
Remedy: To take out color from the fabric treat it with caustic for 45-60 min at 70 deg C. Thereafter treat the fabric with 10-20 gpl Acetic Acid for 40-60 min at 80-85 deg C.
Defect: Uneven dyeing, marks of water, marks of colors
Remedy: Wash the fabric in soap and redye in a darker shade
Defect : The fabric has become stiff and rough after dyeing
Remedy: Finish after adding right softner
Defect: Color staining of fabric, uneven dyeing
Remedy: Redye the fabric in darker shade.
Defect: Color staining in fabrics of darker shade, uneven undyeing
Remedy: Dye the fabric in Sulphur black
Caution: Please treat a small length fabric to check the effectiveness and any harmful effects before commencing a full treatment.
Propylene is one of the constituents obtained from thermal or catalytic cracking of petroleum. Under suitable polymerising conditions, propylene produces fibres forming polypropylene.
Polymerisation: It is done by dissolving propylene in heptane using TiCl3Al(C2H5)3 catalyst system at about 100 deg C under a pressure of 30 Atm for 8 hours. The polymer has a molecular weight of about 80000.
Spinning : Polypropylene is melt spun. The filaments are extruded at 100 deg C above the melting point, cooled in air chamber and collected on bobbins. The filaments are hot drawn (polyethene- cold drawn) and twisted into yarns.
Properties:
1. PP fibres are colorless and have a smooth surface, with round cross section.
2. Tenacity- 4.5-6 gpd Elongation at Break: 17-20 % Elastic Properties at 2% extenstion: Instantenous Stretch for 30 Seconds: 91%, delayed - 9% Moisture Regain: Nil
3. Boiling water shrinks PP by about 15-20% in 20 minutes
In traditional methods in India, printing is essentially carried in three steps:
1. Preparation of the Cloth 2. Mordanting 3. Dyeing
1. First of all the cloth is prepared by applying tannin.
2. A thickened mordant is printed on this tannin treated cloth in the desired pattern.
3. The cloth is then dyed so that dyestuff attaches itself to those parts of the cloth to which mordant has been applied.
Thus the various processes are:
a. Tanning of fabric b. printing of mordant c. fixing of the modant d. washing out the excess of fixing agent e. dyeing f. washing and soaping.
Harda or Myrobalan is used in India as a tanning agent for dyeing and printing with natural colours.
It is applied on scoured cotton fabric in cold ( 10-40 gpl) using conventional method of tub dip wherein the Harda powder is replenished with each piece added to the bath.
After drying various metallic salts such as alum or ferrous sulphate are printed on the fabric either separately or in mixtures.
It is then subsequently dyed with madder root ( Manjith), pometranate rind, kusum flowers and other vegetable dyes.
It is important that the general precautions should be followed while dyeing a textile material. It is always helpful to keep a record of all the conditions (including temperature, time, conc of color, chemicals, material to liquor ratio) in order to get an even shade in each batch. In general the following are the common causes of dyeing defects across all the categories of dyes:
1. The material is not well prepared for dyeing and printing
a. Material having dead fibres or other defective fibres b. Left over of Chemicals after bleaching etc. c. Material not properly desized d. Material not properly mercerised. e. Absorbancy of the fabric not proper f. Sticking of insoluble material on the fibres g. Impurities are not removed properly h. Uneven heat treatment.
2.Water Quality not Proper
a. More Hardness of water b. Water has metal ions such as iron. c. pH of water not proper d. Water having more chlorine
3. Due to Shortcomings in making Dyeing Solution
a. Improper weight ratio of colors, material and chemicals. b. Improper material to water ratio 3. Improper filtering of concentrated colors.
4. Due to Shortcomings in the dye machinery
a. Coming out of Dye liquor during dyeing b. Defective instruments controlling temperature, pressure speed etc.
Fibres made from polymers or copolymers of olefin hydrocarbons such as ethylene, propylene are called polyolefins.
Polyethylene: Of all the fibre forming polymers, polyethylene (made by addition polymerisation) Ch2==Ch2 has the simplest structure.
Manufacture: Ethylene is the principal raw material for producing polyethylene fibres. Ethylene gas is obtained by cracking petroleum.
Polymerisation: Ethylene is polymerised under severe conditions in autoclaves at 200 deg C and 1500 atmospheric pressure in the presence of traces (0.01%) of oxygen acting as a catalyst. The polymer resembles paraffin wax and is characterised by low density.
Spinning : Spinning of polyethylene is carried out by melt spinning. The polymer with a molecular weight of about 15,000 is spun from the melt at about 205 deg C and extended through a spinnerette of 0.1 mm diameter into a current of cooling gas. The filaments are cooled to 15 -60 deg C and stretched 4 to 10 times their original length. The drawn monofilaments are wound on spools.
Properties of polyethylene
a. Polyethylene fibre has a round cross section and has a smooth surface. Fibres made from low molecular weight polyethylene have a grease like handle.
b. Specific Gravity- 0.92 Tenacity - 1.0-1.5 gpd Elongation at Break %- 45-50 Tensile Strength psi - 15000 Softening Range: deg C- 85-90
c The moisture regain of polyethylene is practically nil and hence moisture does not affect the mechanical properties of the fibres.
d. Polyethylene is insoluble in most of the common organic solvents at room temperature.
e. Polyethylene fibres have a high degree of resistance to acids and alkalies at all concentrations even at high temperature.
f. The fibre is generally inert and is resistant to wide range of chemicals at ordinary temperatures. They are attacked by oxidising agents.
Seam strength is the strength of seam assembly in a garment. It is a function of the strength of the thread used for the seam, type of seam assembly in a garment and type of fabric used, among other factors.
Failure of seam assembly can occur either by breaking of sewing thread, tearing of the fabric at the seam, excessive yarn slippage adjacent to the stitches or a combination of the above mentioned conditions.
How to determine seam strength in laboratory
In a lab CRE type tensile testing machines such as INSTRON is used. Before testing the samples are prepared.The method is called Grab Test
If the specimens are from manufactured items such as garment then five speicmens are cut having a length of 270 mm on either side of the stitch line and a width of 100 mm parallel to the stitch line.
If the specimens are prepared from fabric then seam strength is measured in warp, weft and bias directions. In such cases swatches are cut in these three directions.
Also two such swatches from two different rolls are joined by the seam assembly- for which we want to test the strength- to measure the parameters.
Before testing the material is conditioned to standard temperature.
The specimen is mounted on the tensile tester. It is operated until the sewn seam or fabric ruptures. The observation is made whether the rupture is caused by Fabric yarn rupture, sewing thread rupture, sewn seam yarn slippage or a combination of two or more of the foregoing. This will give the seam strength.
Repeat this Grab Test for the fabric specimens from which seam failure test is carried out. The result will give the base fabric strength.
Seam strength ( for each direction) will be calculated by the formula:
Seam strength ( gms/cm)= ( Individual specimen seam breaking force in gms)/ Width of specimen in Jaws i.e. 2.5 cm.
Base fabric breaking strength of the individual specimens are calculated by the formula:
Base fabric strength (gms/cm)= (Base Fabric breaking force in gms of individual test specimen)/ Width of specimen in jaws i.e. 2.5 cm
Seam Efficiency= Seam Strength ( Seamed Fabric Strength) x 100)/ Base Fabric Strength
If this seam efficiency ratio falls below 80%, the fabric has been excessively damaged by the sewing operation.
