basic textile processing terms.Day2.pptx

basic textile wet processing terms & Sequence of operations in wet processing

1. BASIC TEXTILE WET PROCESSING TERMS & SEQUENCE OF OPERATIONS IN WET PROCESSING

2. BASIC TEXTILE WET PROCESSING TERMS Absorbency: The ability of one material to take up another material. In textiles, it is the ability of fibre /fabric to take the water quickly.

3. BASIC TEXTILE WET PROCESSING TERMS pH: Value indicating the acidity or alkalinity of a material. It is the negative logarithm of the effective hydrogen ion concentration. A pH of 7.0 is neutral; less than 7.0 is acidic; and more than 7.0 is basic. Acidic: A term describing a material having a pH of less than 7.0 in water Alkaline: A term used to describe a material having a pH greater than 7.0 in water.

4. BASIC TEXTILE WET PROCESSING TERMS Affinity: Chemical attraction; the tendency of two elements or substances to unite or Combine together, such as fibre and dyestuff. Affinity is usually expressed in units of joules (or calories) per mole.

5. BASIC TEXTILE WET PROCESSING TERMS Preparatory Process or Pretreatments : In textile manufacturing, those processing operations performed on grey fabric, colored fabric, textile yarns or fibres to ready them for dyeing, printing or finishing. For example, typical grey cotton fabric preparation includes singeing, desizing , scouring, bleaching and (optionally) mercerizing.

6. BASIC TEXTILE WET PROCESSING TERMS Grey Fabric :- This fabric is unprocessed or unfinished which hasn't been dyed, bleached and processed . Grey goods are the direct product of weaving when the fabric is still in its natural state

7. BASIC TEXTILE WET PROCESSING TERMS Sizing :- Sizing is the process of giving a protective coating on the warp yarn to minimize yarn breakage during weaving . sizing agents such as starch, polyvinyl alcohol (PVA) and carboxymethyl cellulose are added to provide strength to the fibres and minimize breakage .

8. BASIC TEXTILE WET PROCESSING TERMS Desizing : The process removal of size materials from greige (gray) fabric to prepare for dyeing.  the process of removing the  size  material from  warp yarns  after a  textile  fabric is  woven Continuous Desizing

9. BASIC TEXTILE WET PROCESSING TERMS   Desizing Efficiency :- it is  a measure of its effectiveness to hydrolyse starch into products which are water soluble and as such mechanically removable from cloth . For the determination of desizing efficiency, the amount of size on grey fabric and residual size on the desized fabric is determined . % Desizing efficiency = % Original size - % Residual size ___________________ X 100% % Original size In this method, the bone-dried weight loss (%) of the sample before and after desizing is calculated. First the sized fabric is weighed accurately and its weight is noted as W1. Then the fabric is desized and dried and its weight is noted as W2. The fabric is then treated with 3 g/l (35%) HCl at 70°C for 30 min., dried and weighed; the weight is recorded as W3. Original size = W1–W3 Residual size = W2–W3

10. BASIC TEXTILE WET PROCESSING TERMS Tagewa Test :- This test is suitable for starch based sizes only. The TEGEVA rating scale is a scale, which consists of colors ranging from violet to white; white indicating complete removal of starch and excellent efficiency whereas different tones of violet representing different desizing efficiency – the deeper the depth of violet tone, the minimum is the removal of starch and inferior efficiency. Reagent preparation: Potassium iodide [10 g of KI (100%)] is taken in 100 mL of water, and 0.6358 g of iodine (100%) is added to it. The solution is stirred until complete dissolution of iodine in KI solution has occurred. 800 mL of ethanol is added after this. The volume is adjusted to 1000 mL by adding water to the remaining solution. Method of testing: One or two drops of the above solution is added on to a fabric and rubbed gently. The change in color is analyzed according to the Tegewa scale. The fabric should be cold and no residual alkalinity should be present before testing.

11. BASIC TEXTILE WET PROCESSING TERMS Scouring: In textile processing, treatment of textile materials in aqueous or other solutions to remove nature fats, waxes, proteins and other constituents as well as dirt, oil and other impurities . It is important to scour before dyeing so that all foreign material is removed in order to promote even dye penetration resulting in overall level dyeing of the fabric .  In a bath containing 1-2% owg Anionic Wetting Agent, run goods for 30 minutes at 120-190°F(49-88°C).  Rinse well .  For heavily soiled goods, use: 2% owg                            Orconol CHSA Conc ™ (Scouring Agent) 0.2 oz /gal(1.5 g/L)           Soda Ash

12. BASIC TEXTILE WET PROCESSING TERMS Scouring efficiency can be measure by using weight loss method Determination of weight loss weight loss% = weight before scouring – weight after Scouring __________________________________ X 100 weight before Scouring Standard range of weight loss is 4 to 8 % Soap: Soap is a metallic salt of saturated or unsaturated higher fatty acid.

13. BASIC TEXTILE WET PROCESSING TERMS Souring: The term refers to the treatment of textile materials in dilute acid. Its purpose is the neutralization of any alkali that is present. Bleaching : This is the process in which natural and added impurities in fabrics are removed to obtain clear whites. The polyester rcotton blend fabric are bleached with sodium chlorite ESTIMATION OF  BLEACHING  EFFECT Measurement of Reflectance:  When a fabric is    bleached , its light reflecting capacity increases. The reflectance of a bleached fabric is measured by spectrometer. It can measured light reflectance of    fabric  and can give reflectance curve . tandard range of reflectance 85% (84%-86%) up to 90%.

14. BASIC TEXTILE WET PROCESSING TERMS Coloration: A series of textile operation involved to impart color in textiles. It embraces dyeing, printing, painting, spraying and preparatory treatment as well. Color strength: A measure of the ability of a dye to impart color to other materials. Color strength is evaluated by light absorption in the visible region of the spectrum.

15. BASIC TEXTILE WET PROCESSING TERMS Colorist: In textile coloration, a person experienced in developing color formulas, evaluating samples for color and producing colored samples to meet standards. Dyes/dyestuff: Substances that add color to textiles. They are incorporated into the fibre by chemical reaction, absorption, or dispersion Dyes may be divided into natural and synthetic types. Natural dyes are extracted from root bark, flowers and marine growth. Synthetic dyes are chemically compounded through many processes from coal tar or other sources of hydrocarbon molecules On basis of application it is classified as Acid dye, Azoic dye, Basic dye, Direct dye, Disperse dye, Mordant dye, Reactive dye, Sulphur dye, Vat dye etc. Fluorescent whitening agent is also a dye.

16. BASIC TEXTILE WET PROCESSING TERMS Dyeing : A dyeing process is the interaction between a dye and a fibre , as well as the movement of dye into the internal part of the fibre . Generally, a dyeing process involves adsorption (transfer of dyes from the aqueous solution onto the fibre surface) and diffusion (dyes diffused into the fibre ). Ready for dyeing polyester Dyeing Dyed polyester fabric

17. BASIC TEXTILE WET PROCESSING TERMS Disperse dyes: A class of water- insoluble or slightly soluble dyes originally introduced for dyeing cellulose acetate and usually applied from fine aqueous suspensions. Disperse dyes are widely used for dyeing most of the manufactured fibres . Depth of Shade: a percentage describing the amount of dye used proportional to the dry fibre weight, or OWOG. To dye 100 grams of fibre to a 1% DOS, your dye powder would weigh 1% of 100 grams, or 1 gram.

18. BASIC TEXTILE WET PROCESSING TERMS Cross dyein g : A process of dyeing textiles containing fibres having different dye affinities to achieve a multicolored effect. Self Shade-  Self Shade is the shade of each single dye . Combination Shade : Two or more dye are used to develop a shade is known as combination shade.

19. BASIC TEXTILE WET PROCESSING TERMS Auxiliaries: Chemicals used to facilitate and modify the pre- treatment, dyeing, printing and finishing processes. Fixation: The process of setting a dye after dyeing of printing, usually by steaming or other heart treatment. Carrier: A product added to a dye- bath to promote the dyeing of hydrophobic fibres and characterized by affinity for, and ability to swell, the fibre . Bleeding : Color rinsing out of a finished garment, yarn, or fibre . Bleeding can be excess dye that was not fully rinsed out or dye that was not properly set on the fibre . Indigo is an exception, see crocking .

20. BASIC TEXTILE WET PROCESSING TERMS Sojourn Zone : A "sojourn" zone is typically a part of the heat-setting or finishing process where the fabric is given time to rest and relax under controlled conditions This can help in relieving internal stresses and improving the overall quality of the fabric . Oligomers: are a low molecular weight byproduct of the polymerisation of diethylene glycol and terephthalic acid Oligomers

21. Sequence of Operations in wet processing Grey Fabric Drumming Desizing Scouring Heat set Dyeing Finishing Grey Inspection

22. Brief of All wet processing Terms Grey Fabric It is the raw, unprocessed and unfinished woven fabric taken directly from a loom . Grey goods are the direct product of weaving when the fabric is still in its natural state and has yet to be bleached, dyed, coated or otherwise finished . Many manufacturers purchase grey goods in bulk to cut & sew products or further process them by dyeing, coating or laminating them.

23. Brief of All wet processing Terms Grey Inspection After manufacturing of grey fabric on loom or  knitting machine , it is inspected using an grey fabric inspection machine During this inspection, defects such as knots, broken and loose warp ends, broken weft ends are removed  In case of holes, either it is mended or the fabric is cut off depending on the position of the hole and its severity

24. Brief of All wet processing Terms Objects and purposes of grey fabric inspection : To check diameter and  G.S.M of fabric To identify the fabric faults To ensure about the fabric quantity To ensure fabric Received is of required quality. To classify the products according to the different quality based on the demands of the buyer/market or client . To classify the products according to the different quality based on the demands of the buyer/market or client. Machines are oiled and greased accordingly. S.M,  Stitch length , Tensions are controlled accurately. Machines are cleaned every shift and servicing is done after a month. Grey Fabrics are checked by 4 point grading system.

25. Brief of All wet processing Terms Four point inspection system: Grey fabric inspection is performed according to  4-point system . 4 point numbering system is followed for finished fabric inspection. Defects found in the final inspection SL No Fabric faults SL No Fabric faults 1 Hole 11 Drop stitch 2 Oil stain 12 Dirt 3 Grease stains 13 Needle line 4 Sinker line 14 Thick thin place 5 Hole/pin hole 15 Missing yarn 6 Yn contamination 16 Barre 7 Slub 17 Sattap 8 Wheel mark 18 Broken needle 9 Press off 19 Loop 10 Double yarn 20 Foreign materials

26. Brief of All wet processing Terms Length Point Acceptable Calculation 0  to  3’’ 1 Up to 40 Points/100Yds  = A >3’’ to  6’’ 2 21-30 Points/100Yds       = B >6’’ to  9’’ 3 31-40 Points/100Yds       = C >9’’ 4 Above 40 Points Reject. Hole <1’’ 2 Hole >1’’ 4 AS per formulation: Dia × 36” × GSM ×2 ÷ 1550 ÷ 1000 —————————————————————- Roll wt in KG = Yds

27. Brief of All wet processing Terms General instructions for the final inspection : All pieces will be graded on the base of 40 points per 100 Linear yards Mapping will be done on each piece to insure proper grading. Do not count more than 4 points per one yard. All defects must be recorded and marked in final inspection and an accurate account of points made to insure proper grading. All fabric must meet specifications. At the end of each piece of fabric, the inspector will add up total points and decide whether the piece can be shipped as first quality or not, reworked, placed in lower quality, or cut and upgraded for shipment. Fifteen yards or more can be shipped as first quality. The quality control supervisor must approve the grading of all quality levels and check the lower quality . .

28. Brief of All wet processing Terms General instructions for the final inspection Major or unsightly defects in the first and last yard of a roll or piece will be cut. All defects of one-yard length or more will be cut out of the piece. Defects within the first 2 inches or the last 2 inches of a piece will not be cut out or counted in the grading Open defects on the back of fabric such as drops, runs and hanging picks are to be included in the grading of fabric. Pieces can be connected together, once each piece must be the same shade. All defects such as runs that extend more than a yard in length will be cut out. Fabric up to 70 inches will be allowed a bow of not more than 1 inch and a Bias of not more than 2 inches. Defects within one inch of the fabric edge will not be counted except on tubular fabrics. All defects will be counted in tubular goods.

29. Brief of All wet processing Terms Problems occur during grey fabric inspection: The normal problems in grey inspection are as follows: Disagreement between two inspectors regarding allocating penalty points. It is suggested to have periodic round tests, i.e., getting the same fabric inspected by different inspectors and making them to explain why they consider something as a defect and something as not defect. Let them come to one consensus. By this the difference of agreements shall reduce. Fatigue of inspection; inspectors cannot see certain defects. When same type of fabric is inspected for a long time, the eyes get fatigued and some of the defects cannot be seen. It is therefore necessary to give rest to the eyes for some time by asking the person to do other works like the entries, moving the fabrics, cleaning the area and so on. Demand for inspecting fast, whereas the defective points are more and inspection is getting delayed. When the defects are more, the time taken for inspection increases as each defect need to be marked, flagged and data entered in the system.

30. Brief of All wet processing Terms Grey Fabric Grading: The grading has two primary functions: First, to classify the fabrics according to standard qualities based on the end-use and costumer demands and second, to supply information as to the qualities actually being produced. The First quality level ……………..40 points per 100 Linear Yards. The Second quality level …………(40 – 80) points per 100 Linear Yards. The Third quality level …… 80 points or more per 100 Linear Yards.

31. Brief of All wet processing Terms Grading procedure: All open defects or major defects counted with 4 points per defect. Surface defects over 9-inch length counted with 4 points per defect. Surface defects 6 to 9 inches length counted with 3 points per defect. Surface defects 3 to 6 inches length counted with 2 points per defect. Surface defects up to 3 inches length counted with one point per defect. Running defects, such as tucks, needle lines, barre , crack marks, are judgment defects

32. Brief of All wet processing Terms Reeling Machine (Charkha):- The goods which will be processed in drum m/c is reeled on charkha Several numbers of stitches are taking out on the reeled fabric according to the quality No. of stitches are suggested as per quality like 12 stitches are taking out on 30*30 GGT.

33. Brief of All wet processing Terms Drumming – It is carried out in Rotary Drum It opens the yarn twist thereby giving grainy effect to the fabric . MLR is 1:4 Kleenox TEP (swelling agent) :- 0.3 to 0.5 % o.w.f The pressure is 2-3 kgs /cm2 . Holding time is 45-90 mins .

34. Brief of All wet processing Terms Desizing   – It is meant for removing regular and water jet loom sizes co-polymers. HTHP Jet dyeing machine is used MLR is 1:4 in U- tube and 1:8 in long tube Kleenox BAS ( Desizing Agent) – 1-2 gms /lit Adjust pH 5.5 -6.0 with acetic acid & Run for 20 mins at room temp Add Soda ash 2-4 gms /lit, Raise temperature to 100 deg c by 1 deg c /min gradient, then . Hold for 45-60 mins . Hot drain Hot wash at 95 deg cwith 0.5 gms /lit Kleenox BAS for 10 mins then . Cold wash In some units they are doing single bath desizing and drumming in the Rotary Drum HTHP m/c. It saves time and energy to avoid separate desizing process in different machine e.g., Jet or Jigger

35. Brief of All wet processing Terms Scouring It is required for high twist 100 % polyester  qualities It is carried out as Single bath Scouring & Weight Reduction in HTHP Jet Dyeing machine The MLR is 1:3 – 1:4 in U – tube Load the material and give cold wash Then add Greenscour CPM (Scouring agent) – 2-3 gms /lit   Kleenox BASM (wetting agent alkali stable) – 2-3 gms /lit. Then Run for 15 mins at room temp. Add Caustic soda flakes as per weight reduction required Raise temp to 120-130 deg c. hold for 30-60 mins Then Hot drain. Hot wash at 95 deg c for 15 mins  with addition of Oligo EM ( Remove oligomer) -1 gm /lit Then neutralization with Oxalic acid – 4 gms /lit. Kleerix N (neutralizer for alkali treated fabric) – 1 gm /lit. At 90 deg c for 20 mins .

36. Brief of All wet processing Terms Stentering : 100% polyester filament yarn fabrics may be arranged in the following three sequences. Scour – Heatset – Dye Heat set –Scour— Dye. Scour—Dye—Heat set . Heat-setting is a heat treatment by which shape retention, crease resistance, resilience, and elasticity are imparted to the fibers. It also brings changes in strength and stretchability

37. Brief of All wet processing Terms Dyeing Dyeing of polyester fabrics –    There are basically two types of polyester fabrics Polyester knitted fabrics. Polyester woven fabrics . Polyester knitted fabrics are composed almost exclusively of texturized yarn. To avoid creases and breakages, knitted fabric that have not been set should always be stored or treated in full width .

38. Brief of All wet processing Terms The process sequence for circular knitted fabrics dyeing is as below . Pre-stabilization Full width washing Hydro-Extraction Heat-setting Dyeing Hydro-Extraction Drying Steaming Slitting Drying Finishing

39. Brief of All wet processing Terms Slitting :- A "slit" in knitting refers to an intentional opening or gap created within the fabric. Slits can be functional, decorative, or both, and they are often used in garment designs to allow for ease of movement, to create stylistic elements, or to accommodate features such as pockets or closures.

40. Brief of All wet processing Terms Following are the precautions taken for the above process. Circular knitted fabrics should be slit as soon as possible after knitting (within 24 hours). If they cannot be further processed immediately, they must be rolled flat, completely free from creases. If the goods are stored in tubular form for some time, the folds will become fixed. Prestabilizing  is necessary if the fabric is liable to become creased during precleaning or if the selvedges tend to curl. This is done by running the fabric in a tensionless state through a steaming chamber ((saturated steam ,100deg c.); the fabric relaxes, and fibres begin to crimp. Prior to dyeing, all spin finish, knitting machine oil and other impurities must be removed. At the same time washing develops the crimp which is lost in knitting. Scouring is carried in continuous full width washing ranges using Soda Ash and good detergent. There should be provision of a “sojourn” zone, in which the fabric is able to relax completely without longitudinal tension. The shrinkage is often over 20 %.

41. Brief of All wet processing Terms After washing, rinsing, hydroextraction uniform drying is essential because variations in the residual moisture content are liable to cause uneven fixation, resulting in unlevelness in dyeing. Heat setting is done in stenter at 150-180 deg c for 20-30 seconds. The higher the setting temperature, the better the dimensional stability of the treated fabrics., but the handle becomes flatter and harsher if the setting temperature is too high. Texturized polyester knitted fabrics are normally dyed at 130 deg c in high temperature winch –beck. it gives a full, bulky handle to the goods using medium to high sublimation fastness disperse dyes. It can also be dyed in Jet dyeing machines using defoamer , anticrease agent etc

42. Brief of All wet processing Terms Jet Dyeing machines – It is suitable for dyeing of polyester knitted fabrics and woven fabrics. Following are the advantages of the above Exhaust dyeing process no tailing problems. better reproducibility. less fastness problems. good penetration. Care must be taken to avoid Rope marks in jet dyeing machines which may be due to the following reasons improper heat setting. too low a fabric speed. The remedial measures are ensures proper heat setting. at least 1 revolution per min. use suitable lubricants.

43. Brief of All wet processing Terms Finishing of polyester fabrics Several finishes can be given to polyester fabrics to increase their usefulness. Some of the important ones are as below. Antistatic Finish – for reduction of electrostatic build –up. Calendaring – for smoothness and reduced pilling. Compressive shrinkage – for increased shrink resistance. Embossing – for design and luster . Water and Soil repellency – for comfort and ease of care.

44. Brief of All wet processing Terms Zylan MAT – Mat Finish – Dose 10 -15 gms /lit. It is suitable for bright filament –yarn qualities. It gives good bouncy effect. It gives Matt look with cotton feel. b. Drybounce CST –Dose 10-15 gms /lit. It is suitable for both bright and georgette qualities of dress material with heavy weight reduction. It gives very good bouncy feel with complete dry touch. It is suitable for both pad and exhaust. c. Innersol GTX  – Dose – 5-10 gms /lit. It is suitable for 100 % polyester and blends. It gives wet feel with soft surface touch. It gives smooth surface with inner softness. d. Dry Peach – It  is suitable for pad only. It gives very high bounce with dry peach surface. More suitable for bright qualities of sarees and dress material. Following chemicals are used Zylon RS – 20-30 gms /lit. Ultima XT 50 – 15-20 gms /lit Drybounce CST – 5-10 gms /lit.

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