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Engr. Abu Sayed, M.Sc in Textile Engineer, Email id-
Engr. Abu Sayed, M.Sc in Textile Engineer, Email id-
Lab Dip:
Lab Dip Development means the sample...
Engr. Abu Sayed, M.Sc in Textile Engineer, Email id-
Working Procedure in Lab Dip:
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Lab dip
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  1. 1. 1 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- DEDICATED TO MY DEAR SIR MR. SAJESH PERINGETH Abu Sayed Sajesh sir ACKNOWLEDGEMENT At first, I gratefulness goes to Almighty God to give us strength and ability to understand good or bad. You have made our life more beautiful. May you name be exalted, honored and glorified. I am Abu Sayed, not big man but simple man. My home district is Tangail. I am proudful that my father is a farmer. I have completed the M.Sc in Textile Engineering from Daffodil Internatioanal University. I am working as laboratory Manager in a reputed group at Narayanganj. I want to give my heartiest gratitude to my dear sir Mr. Sajesh (Quality Assurance Manager). Thanks goes to all Engineers, officers, technicians, employees, staff and all section in- charges for their cordial behavior help. SUMMARY This Manual has arranged on the basis of Textile Dyeing lab procedure, calculations & ETP etc. Here presenting some Lab & Dyeing calculations in my Practical life. I am not Writer & If I any mistake, Excuse me. You mind it man is wrong.
  2. 2. 2 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Lab Dip: Lab Dip Development means the sample which is dyed according to buyer’s requirements (similar shade and so on). Depending on lab dip development sample dyeing and bulk production dyeing planning is done. Lab work plays an important role in dyeing process. Bulk dyeing process completely depends on the lab dip development work. Lab work is completely managed as the following sequence. Lab dip is a process by which buyers supplied swatch is matched with the varying dyes percentage in the laboratory with or without help of “DATA COLOR”. Lab dip plays an important role in shade matching & and detaching the characteristics of the dyes and chemicals are to be used in the large scale of production. So this is an important task before bulk production. Object of Lab Dip: The main objectives in lab dip are as follows: 1. To calculate the recipe for sample dyeing. 2. To compare dyed sample with swatch by light Box or Spectrophotometer. 3. To calculate revise recipe for sample dyeing. 4. Finally approved Lab Dip (Grade: A, B, C & D) Common Stock Solutions: Red – 0.1%, 0.5%, 1.0%, 2.0% (very common) Yellow – 0.1%, 0.5%, 1.0%, 2.0% (very common) Blue – 0.1%, 0.5%, 1.0%, 2.0% (very common). Preparation: To prepare 0.1% Stock solution, it is necessary to mix 0.1 g dye and 100 cc water. To prepare 0.5% Stock solution, 0.5 g dye stuff is mixed with 100 cc water. To prepare 1.0% & 2.0% Stock solution similar procedure is followed. To prepare 10% Stock solution of Soda ash, 10 g Soda is mixed with 100 cc water. Depth of Shade: 0.5% to 5% shade for the goods. Lab Dip Calculation: Usually following calculations are followed: Dye Solution = (Shade % * Sample Weight) / (Stock solution %) (cc). Salt = (Shade % * Liquor) / 1000 (gram per liter, gpl). Soda Solution = (Shade % * 100 * Liquor) / (1000 * Stock solution %) (cc). Sample Calculation for 0.5% Shade: Sample wt. = 5 mg Material liquor ratio = 1: 10 Total liquor (5 * 10) = 50 cc Dye solution required = (5 * 0.5%) / 1% = 2.5 cc Salt solution required = (50 * 25) / (20 * 10) = 6.25 cc Soda ash solution required = (50 * 10) / (20 * 10) = 2.5 cc Water required = {50 – (2.5 + 6.25 + 2.5)} = 38.75 cc
  3. 3. 3 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Working Procedure in Lab Dip: All ingredients had been taken according to the recipe into the pot of sample dyeing machine. At a room temp the material had run then after 10 minutes started to rise the temperature at 1°C/ min. to get 60°C temperature. For performing the required dyeing temperature it took 30 minutes. The material had dyed at 60°C for 45 minutes. Then the temperature was reduced at room temperature within in 10 minutes. The fabric washed in cold water & then the material was washed in 1 gm/l soap solution (liquor ratio 1:20) at 90°C temperature for 15 minutes. Then after rapidly cold washing the material was dried & preserved. And then check the shade match with the required sample by the lighting box. Then send to buyer or merchandiser for approval. Working Procedure of Sample Dyeing (Knit Dyeing Section): Normally a textile dyeing mill get offer through merchandiser. Merchandising department of dyeing mill send the swatch to the central dyeing lab. Then the lab manager analysis the color of swatch with the help of spectrophotometer. After shade matching three sample are submitted to the buyer or buyer agents. If sample is approved by the buyer then this sample recipe are sent to floor for bulk production. The dyeing master dyeing the sample for bulk production. Now I will give the flowchart of sample dyeing for bulk production. Sample dyeing machine (Scouring and Bleaching) Water load in sample dyeing machine ↓ Fabric load ↓ Temperature raised in 500 C ↓ Scouring chemical added (dosing time 10min) ↓ Temperature raised in 600 C ↓ NaOH dosing ( dosing time 5min) ↓ Temperature raised in 700 C ↓ Hydrogen Peroxide dosing (dosing time 10min) ↓ Temperature raised in 100-1100 C and running at 30min ↓ Cooling at 800 C ↓ Ringe or normal wash (10min) ↓ Drain out ↓ New water load
  4. 4. 4 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- ↓ Temperature raised in 550 C ↓ Add acid + OEM ( for destroying Hydrogen Peroxide power) ↓ pH check and obtain 4.5 by adding acetic acid ↓ Enzyme is added and run time 60 min ↓ Sample check if approved by incharge ↓ Ringe (run time 15min) ↓ Drain out (Dyeing) New water load ↓ pH check and obtain 5.6 by adding acetic acid ↓ Temperature raised at 50-550 C ↓ Dyeing auxiliaries added (leveling agent, anti creasing agent, sequestering agent etc) ↓ Salt added and running at 10min ↓ Color is added and dosing time 30 min ( Reactive dye, Disperse dye, Acid dye etc) ↓ Running time 25 min ↓ Temperature raised at 600C ↓ Soda ash (dosing time 35 min) ↓ Sample cutting for checking after 10 min later ↓ If approve then ringe at 20 min ↓ New water load ↓ Add acetic acid for neutralization at 400 C and run at 10min ↓ Ringe at 5 min ↓ Drain out
  5. 5. 5 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- ↓ New water load ↓ Temperature raised at 90-950 C and 10 min running ↓ Cooling at 800 C ↓ Ringe ( for cut sample) ↓ Shade checking if approve by incharge then ↓ Ringe and running at 15 min ↓ Drain out ↓ New water load ↓ Temperature raised at 300 C ↓ Fixing agent added ( GG-100, ECO, CR) and dosing time 10min ↓ Ringe ( 10min) ↓ Drain out ↓ New water load ↓ Temperature raised at 400 C ↓ Softener added and run time 30 min ↓ Shade matching if approve then ↓ Fabric unload.
  6. 6. 6 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Cotton fabric dyeing by Reactive dyes Sample weight = 5 gm. M: L = 1: 10 Recipe: Reactive dyes = 0.8 % Reactive dyes = 1.0 % Reactive dyes = 0.05 % Salt = 30 g/l Soda = 10 g/l Calculations: We know, Dyes = F. weight in gm x shade % Stock solution % Water = 50 ml. Suppose, Stock solution = 1 %. Reactive dyes = 5 gm x 0.8 % = 4 ml. 1 % Reactive dyes = 5 gm x 1.0 % = 5 ml. 1 % Reactive dyes = 5 gm x 0.05 % = 0.25 ml. 1 % Salt = 30 g/l = 30 x 50 / 1000 = 1.5 gm. Soda = 10 g/l = 10 x 50 / 1000 = 0.5 gm. Total volume = 50 ml Required water = 50 – (4+5 + 0.25) ml = 40.75 ml. In dye pot, 5 gm sample + 4 ml +5 ml + 0.25 ml + 1.5 gm + 0.5 gm + 40.75 ml. Time & Temperature = 60 min x 600 C. FABRIC DYEING Fabric dyeing is the method after weaving, knitting or non-woven to make fabrics. This is very popular method of dyeing as the dyed fabrics will be processed further to garment industries very easily. Dyeing forms of the fabric dyeing can be used in 2 ways. 1. Open width form using the fabrics to spread without any creases and dye them. 2. Rope form using the fabrics with the form like a rope. Dyeing work flow chart: Scouring & bleaching ↓ Per oxide hot with a/acid ↓ Enzymes wash with a/acid ↓ Leveling with sequestering ↓
  7. 7. 7 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Dyeing dosing ↓ Salt dosing ↓ Soda dosing ↓ Sample ↓ Drain ↓ Washing off ↓ A/acid ↓ Softener ↓ Unload Working Procedure: Firstly the detergent, Anti-creasing agent, Anti-foaming agent and Stabilizer are mixed in mixing tank, then load to machine at 50°c ↓ The temperature is risen to 60°c. Now the Caustic Soda is given to bath ↓ The Hydrogen Peroxide is given at 70°c ↓ Raise the temperature at 98°c and run for 60 minutes. Here the Ph = 11-12 ↓ Rinse the fabric ↓ Hot wash is done at 80°c × 10 → Drain → Normal wash → Drain ↓ Peroxide is applied at 60°c and run for 15 minutes → Hot wash ↓ Add Acetic Acid at same temperature and run 10 minutes ↓ pH checked (pH=6.5) → Normal wash ↓ Now Acetic Acid applied at 55°c for pH control (pH= 4.50) and then Enzyme is given to bath at same temperature with 60 minute ↓ Raise the temperature (Grade rate → 2 C/min) at 80°c and run 6 minute ↓ Cold wash is done 2 times and the drained out.
  8. 8. 8 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Procedure for Lab dips by the Different Dyestuff in the Laboratory: Procedure for100 % Cotton Fabric: 1. Calculate the recipe. 2. Weight the fabric. 3. Take the beaker keep the fabric in to the beaker. 4. Then the dyes, chemicals & required amount of water take in to the beaker by the digital pipeting. 5. Then weight the salt by the electric balance and add in to the beaker. 6. Then the beaker set in to the lab dyeing machine for dyeing. 7. Start the program for dyeing the whole dyeing time 60 min at 60 °C temperature. ( the dyeing time and temperature depends on which classes of dyes are used for dyeing .) 8. After 30 min add the then add the soda ash . by pipeting . 9. Again run the program next 30 min at the same temperature . 10. Finished the dyeing time then the sample taken from the beaker first hot wash & then cold wash. 11. Then acid wash as for neutralization. 12. Then soaping required soap solution 10 min at 90° C temperature. 13. After the fabric again cold. 14. Then dry the lab dip and compare with the standard. Turquoise Color: Turquoise is the color of the gem turquoise. It is a slightly greenish shade of cyan. Turquoise is sometimes described as a mixture of pale blue and green. The name comes from the French for Turkish. Turquoise Color Types of Turquoise Color: There are six type of Turquoise Color. They are given below: 1. Pale Turquoise (web color) (Hex: #AFEEEE) (RGB: 175, 238, 238) 2. Turquoise Blue (Hex: #00FFEF) (RGB: 0, 255, 239) 3. Bright Turquoise (Hex: #08E8DE) (RGB: 8, 232, 222) 4. TURQUOISE (web color) (Hex: #40E0D0) (RGB: 64, 224, 208) 5. Medium Turquoise (web color) (Hex: #48D1CC) (RGB: 72, 209, 204) 6. Deep Turquoise (web color Dark Turquoise) (Hex: #00CED1) (RGB: 0, 206, 209)
  9. 9. 9 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Process Flow Chart for 100% Cotton Knit Fabric (Turquoise Color): Turquoise is very sensitive color. Its wash fastness is not good. Dyeing process of turquoise color is slightly difference from other color process. Process Sequence of Turquoise Color: Fabric loaded ↓ Treating with anti-creasing agent (Room temperature) ↓ Adding detergent ↓ Adding Antifoaming agent ↓ Caustic dosing (dosing 6min) ↓ Peroxide dosing (60˚c; 5min) ↓ Run time 1 hour 95˚c ↓ Sample check ↓ If ok ↓ Drain out ↓ Normal hot (70˚c, 10min) ↓ Drain ↓ Adding Peroxide Killer ↓ Run time 55˚c, 10min ↓ Adding Acetic Acid ↓ Run time 10min 55˚c (ph-4.5) ↓ Adding enzyme ↓ Run time 1hour, 55˚c ↓ Enzyme hot- 70˚c, 10min
  10. 10. 10 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- ↓ Drain ↓ Filling in the tank (run time 5min) ↓ Rinsing -4min ↓ Drain ↓ Filling in the tank ↓ Adding Leveling, Antifoaming & Anti-creasing agent (R.T.) ↓ 10min run time (R.T.) ↓ 10min run time (60˚c) ↓ Color dosing-30min ↓ 10min run ↓ ½ Salt dosing-5min ↓ ½ Salt dosing -5min ↓ Runtime -25min (60˚c) ↓ Sample check ↓ Soda dosing (2 g/l; 20min) ↓ Remaining Soda dosing (30min) ↓ 20 min run ↓ Temp rise 80˚c ↓ Run time-1 hour ↓ Rinsing-5min ↓ Drain ↓
  11. 11. 11 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Filling in the tank ↓ Run time (RT) ↓ Drain ↓ Filling in the tank ↓ Normal hot (60˚c,10min) ↓ Sample check ↓ Drain ↓ Adding Acetic Acid (room temp, run time-30min) ↓ Sample check ↓ Drain ↓ Filling in the tank ↓ Adding soaping agent (90˚c, run-10 min) ↓ Drain ↓ Sample check ↓ Filling in the tank ↓ Rinsing (5min room tem) ↓ Drain ↓ Filling in the tank ↓ Run time (5min, room tem) ↓ Drain ↓ Filling in the tank ↓ Dosing-fixing agent (15min)
  12. 12. 12 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- ↓ Run time (20min, room tem) ↓ Sample check ↓ Drain ↓ Filling in the tank ↓ Dosing softener (5min) ↓ Run time (20min, room tem) ↓ Sample check ↓ Unload. Package Dyeing (HT HP) - Cheese Yarn Dyeing-II Reactive Dyeing of cotton yarn in cheese form: Whether it is Vinylsulphone or Bifunctional dyestuff, you may follow the following dyeing cycle for yarn dyeing: The Chemical table shown below contains a Code No. that has to be included time to time when the dyeing process is going on. Code No Name of Chemical Grams/liter 1 Acetic Acid 0.5 Sequestering Agent 0.5 2 Acetic Acid 0.5 Vacuum Salt or Glauber's Salt As Recommended 3 Dyestuff O.W.F. 4 Soda Ash As Recommended 5 Acetic Acid 0.5 6 Sequestering Agent 0.5 Anionic Soap 0.5 7 Acetic Acid 0.5 8 Dye fixing Agent Not Necessary 9 Softener 1.0
  13. 13. 13 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Processing Cycle for Yarn Dyeing:  Set the dye bath with soft water at ambient temperature and as per MLR  Enter the RFD (Ready For Dyeing) yarn in to the processing vessel.  Add Chemical [Code-1]. Circulate for 3 minutes (In -> Out) and hold for 10 minutes. Drain.  Check pH. It should be 6 - 7. Check for channeling.  Fill cold water, add chemicals [Code-2], Circulate for 5 minutes (In -> Out) and hold for 10 minutes.  Raise temperature to 40°C and hold for 5 minutes.  Add dissolved dyestuff [Code-3] in 2 to 3 portions with Out -> In circulation at 40°C.  Raise temperature to 60°C @ 1.5°C/minute and hold for 15 minutes.  Add Chemicals [Code-4] in two parts with In->Out circulation and run for 45 minutes.  Check the sample and drain the dye bath.  Rinse at room temperature for 5 minutes and drain.  Give overflow rinse as per the dept of shade - 3 to 5 minutes.  Fill fresh water, add chemicals [Code-5] and hold for 5 minutes. Drain.  Fill hot water (60°C), add chemicals [Code-6] and circulate for 3 minutes.  Raise the temperature to 95°C and run for 15 minutes. Drain.  Rinse at 70°C for 10 minutes followed by 5 minutes overflow wash. Drain.  Fill fresh cold water, add chemicals [Code-7] & [Code-8] and circulate for 3 minutes, hold for 15 minutes and then drain.  Fill Cold water, add chemicals [Code-9], circulate for 3 minutes and hold for 10 minutes. Drain.  Unload the batch. Notes on Dyeing:  For Shades above 7%, two soaping operations are necessary.  Dye fixing is optional but not a substitute for thorough washing.  Pressure difference during In->Out and Out ->In operations has to maintain a constant. Package Dyeing Of Unmercerised Cotton Yarn With High Exhaust Reactive Dyes
  14. 14. 14 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- · Start Dyeing @50°C; ensure the starting bath pH be 6; adjust with Acetic Acid if necessary. · Add salt (vacuum or Glauber’s salt) and hold for 15 minutes. · Add ½ the volume of dissolved and filtered dyestuff and hold 10 minutes. · Add ½ the volume of dissolved and filtered dyestuff and hold 10 minutes. · Raise the temperature @2°C/minute to 80°C and hold for 20 minutes. · Add ½ alkali (Soda ash) and hold 25 minutes. · Add ½ alkali (Soda ash) and hold for 30 minutes. · Check sample. · Drain. · Cold wash (10 + 10 minutes). · Neutralize @ 40°C with adequate qty of Acetic acid. · Cold wash – 10 minutes. · Hot Wash @ 70°C (2°C/minute) – 10 minutes. · Soap @ 95°C – 15 minutes (1st soap). · Soap @ 95°C – 15 minutes (2nd soap) · Soap @ 95°C – 15 minutes (3rd soap) · Hot Wash · Sample check for shade and wash fastness · Cold wash (10 + 10) minutes · Acid wash with 1 gpl of acetic acid · In the same acid bath – cationic softener treatment – 20 minutes · Check pH – 6 · Unload. Lycra Yarn – Pretreatment in Package dyeing machine: Machine Circulation Cycle Settings: Cheese winding: on plastic cones or cheeses. Cheese Weight: Not more than 500 grams/cheese  DEMINERALIZATION: o Recipe:  Kierlon Jet B Conc = 0.05%  Lufibrol MFD = 0.05%  @ 50°C for 2 cycles  This is done to remove the unwanted mineral contents from the fiber.  Hot Wash = 1 cycle @ 50°C  Cold Wash = 1 cycle
  15. 15. 15 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id-  BLEACHING: o Recipe:  Soda Ash = 2.0%  Stabilizer = 0.5%  Lissopol D paste = 0.5%  Hydrogen Peroxide(50%) = 2.0%  @ 65° to 70°C for 45 to 60 minutes.  Set the bath with chemicals other than H2O2.  Raise temperature @ 1.5°C/minute  Hot Wash = 1 cycle @ 50°C  Peroxide Killer Treatment: o Recipe:  Organic Peroxide killer = 0.25%  Acetic acid = 1.5 g/l  @ 50°C for 1 cycle  Drain, Cold wash  Start Dyeing. Note: 1. Bleaching temperature should not go beyond 65 to 70°C 2. Cheese weight = 500 grams and less is safer. 3. If you want to use regular cheese weights of 800 to 1000 grams, then the cheeses have to be conditioned in the autoclave with moist steam at 100°C for 30 minutes, repeatedly, so that a stable shrinkage percentage of yarn is reached. The linear shrinkage % should be 20 to 25%. Sample dyeing process for cotton Recipe for cotton fabric Recipe for Machine Wash Pretreatment Wetting agent (NOF) – 0.5g/L Sequestering agent (2146 – 1g/L Anticreasing agent (JN) – 1g/L Stabilizer (SIFA) – 0.7g/L Caustic – 2g/L H2O2 – 4g/L Detergent (Sol ax) - 0.5 gm/L Caustic -1 gm/L Hydrous - 2 gm/L Neutralization Acetic Acid – 0.5g/L Fabric weight Enzyme treatment Enzyme UL – 1g/L Fabric cold wash Dyeing A/Acid – 0.5g/L Leveling agent – 1g/L Ant creasing agent – 1g/L Dyes – X % Salt – X g/l [salt & soda depend on liquor ratio
  16. 16. 16 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- but general formula is 6:1 salt: soda, if used power soda then 3:1] Soda – X g/L Recipe calculation After Treatment Fixing agent (Neofix ECO/CIBA fix FRD) - 0.5 g/l Soaping agent(Lipotol PS-60) - 0.8 g/l Acetic acid - 1 g/l Dye + Salt + Water and other chemicals Softening Acetic acid - 0.2 g/l Softener (Perrostol CWS) - 1 g/l. Are taken by pipette in the pot, Then wash fabric keep in the pot Set. Time and temp. (60-80˚c x 60) Fabric unload Cold wash 2 times Hot wash with Rsk Dyer Shade matching. Sequence of cotton fabric dyeing Sequence of white fabric dyeing for cotton Fabric loading Required amount of water was taken (1:10) Required amount of water was taken into the M/C Scouring [NOF-0.5g/l, 2146-0.5g/l, JN-0.5g/l, SIFA0.7g/l, NaOH: 3-4g/l, H2O2 4-8g/l 110°c x 60 ́]. Fabric loading Hot wash [NOF, Soda 90°c x 20, 1:10] Acid wash /chemical remove [A/Acid-0.5g/l, H2O2-0.5g/l, 60°c x 10 ́]. Scouring [NOF, 2146, JN, SIFA, H2O2 110°c x 60 ́] Enzyme [Enzyme: 0.5g/l; UL/Biosoft 2xl. 50°c x 60 ́ PH 4.5]. Wash Leveling [LRDS-0.5-1g/l, JN -0.5g/l10 ́ PH 6.5-7]. Acid wash /chemical remove [A/Acid 60°c x 10 ́] Salt (Glaubar salt– 60g/l) Enzyme [Enzyme UL 50°c x 45 ́ PH-4.5] Color [60°-90°c x 60 ́] A/Acid [PH - 6 - 6.5] Soda (power soda – 15g/l) Syno white 4BK [60°-80°c x 20 ́] RSK hot [60°c x 60 ́] Washing A/Acid (neutralization) A/Acid Fixing [Dyaploe-Dco 30°c x 10 ́ PH 5.5] Softener [Hcs] Softener [HCS 40°c x 20 ́] Washing Unload the dyed fabric
  17. 17. 17 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Calculation for Lab Deep: Recipe Calculation Formula: Dye = (Shade % * Weight of the fabric in gm) / Stock solution %. Or, Required solution = WP / C Where, W = weight of fabric, yarn, or fiber P = shade percentage C = concentration of stock solution CC = cubic centimeter. For auxiliaries (chemicals) the formula is as below: Required amount of solution (mls) = (g/l required * wt of substrate * LR) / (10 * concentration (%) of stock soln) For addition of auxiliaries in solids form such as salt the formula is: Salt in g/l = (Required amount (%) * Sample weight * LR) / 1000 Conversion formula from percentage to g/l is as below: g/l = required amount (%) * 10. Calculation of Dyeing Recipe If alkali conc. Is given in be. Then the formula to calculate this in g/l is as follows: Required amount of solution (mls) = (g/l required * wt of substrate * LR) / (10 * concentration (%) of stock soln) Or, = (Required amount (%)* wt of substrate * LR) / (Concentration (%) of stock soln) Or, Required alkali soln in c.c. = ( g/l required * wt of substrate * LR) / (10* conversion value from Be. to g/l of alkali ) Or, Required alkali soln in c.c. = (Required amount (%) * wt of substrate * LR) / conversion value from Be. to g/l of alkali Example: Suppose a lab deep of a fabric sample (1*1 ribs) has to be formed with following dyes & chemicals: Dyes: 1. Rema Blue RR = 1.122% 2. React Red KHW = 2.014% 3. React Yellow KHW = 1.486% Salt = 70% Soda Ash (conc.20%) = 5 g/l Caustic Soda (38 Be) = 1.32% L: R = 1:8 Sample Wt. = 5 gm
  18. 18. 18 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- % Stock Soln = 1 Therefore, recipe calculation for dyes and auxiliaries in g/l will be as follows: For dyes: We know, Dye = (Shade % * Weight of the fabric in gm)/ (Stock solution %) For, 1. Rema Blue RR = (1.122*5)/1=5.61 g/l 2. React Red KHW = (2.014*5)/1= 10.07 g/l 3. React Yellow KHW = (1.486*5)/1= 7.43 g/l. For auxiliaries: We know, Salt in g/l = (Required amount (%) * Sample weight * LR) / 1000 Required Salt = (70*5*8)/1000 = 2.8 gm. For Soda ash (conc.20%): We know, Required amount of solution (mls) = (g/l required * wt of substrate * LR) / (10 * concentration (%) of stock soln) Required amount of soda ash in C.C. = (5*5*8)/(10*20) = 1.0 For Caustic soda (38 Be.): We know, Required alkali soln in c.c. = (Required amount (%) * wt of substrate * LR) /conversion value from Be. to g/l of alkali Required caustic soda = (1.32*5*8)/441 = 0.12 c.c. [Since 38 °Be.NaOH= 441 gm NaOH 100% per 1lit NaOH soln] Extra Water required: = M:L – (required water to make soln of dyes & auxiliaries) = (5*8) – [(5.61+10.07+7.43) + (1.0+0.12) ] = 40 – 24.112 = 15.77 (Salt is added in solid form) Equipments of Recipe Section: Microprocessor pH Meter (Hanna Instrument) Digital pipette Digital Weighting Meter with Glass Box (Explorer, USA) There are different matching systems followed in Labs. They are: Tube light matching. Sun light matching. Ultra Violet matching. Sodium light matching (show room).
  19. 19. 19 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Process Sequence of Lab Dip: Lab dip plays an important role in dyeing process. Bulk dyeing process completely depends on the lab dip development work. Lab dip is completely managed as the following sequence. Lab Dip Requisition from buyer ↓ Entry in the computer ↓ First recipe is given by swatch/pantone number ↓ First correction ↓ Second correction ↓ Grading of sample (A, B, C, D) ↓ Yarn and knit sample send to buyer ↓ Approved by buyer ↓ Order for bulk production ↓ Production card with approved sample and recipe send to production section. Process Flow Chart/Sequence of Dyeing Lab At first dyeing is performed in dyeing laboratory and then starting for bulk production. A lots of work is done in the dyeing laboratory. In the dyeing lab, lab dip or sample is developed by the dyeing master. Lab dip plays an important role in shade matching & this is an important task before bulk production. Process Sequence of Dyeing Lab: Sample/Swatch/Panton no. / TCX no. / TPX no. from the buyer ↓ Determination of sample’s possible color combination by the help of Spectrophotometer or manual ↓ Dispersion by autodoser ↓ Trial dyeing of first recipe ↓ Unload ↓ Normal wash ↓ Hot wash with detergent
  20. 20. 20 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- ↓ Oven drying ↓ Ironing ↓ Shade matching in light box ( If Ok then send to buyer for approval) ↓ If not ok ↓ First correction takes from Spectrophotometer or manually ↓ Dispersion by autodoser ↓ Trial dyeing of first recipe ↓ Unload ↓ Normal wash ↓ Hot wash with detergent ↓ Oven drying ↓ Ironing ↓ Shade matching in light box ( If Ok then send to buyer for approval) ↓ If not ok ↓ Second correction takes from Spectrophotometer or manually ↓ Dispersion by auto doser ↓ Trial dyeing of first recipe ↓ Unload ↓ Normal wash ↓ Hot wash with detergent ↓ Oven drying ↓ Ironing ↓ Shade matching in light box
  21. 21. 21 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- ↓ If ok ↓ Send for buyer’s approval ↓ Bulk production by considering the buyer’s approved sample as standard Note: This procedure is applicable for yarn or fabric dyeing. Reactive Dyes - Shade Card 1 Reactive Dyes are used for all cellulosic Fibres, Silk & Viscose Rayon. These colours react with cellulose in presence of alkali and also form chemical linkage resulting excellent fastness. Reactive HE' Dyes are reactive dyes containing Bismonochlorotriazinyl group as reactive redical and high fixation on dyeing fabric blends or, Terycot.These colours are suitable for exhaust dyeing (801C) of medium and heavy depths. Salt and Alkali Requirements: Depth of Shade Salt gm per lit Soda Ash gm per (O.W.F.) (Na2 .SO4) (Na2CO3) 0 - 0.5% 30 10 0.5 - 1.0% 45 15 1 - 2% 60 15 2 - 4% 70 20 Above 4% 90 20 Dyeing at 800C for 1 hour of the final alkali addition. Reactive VS' Dyes are reactive dyes containing Vinyl Sulfone groups as reactive radical Suitable for exhaust dyeing (60°C) , continuous dyeing and printing. Dyeing at 60°C Material to Liquor Ratio 1:2 to 1:3 1:4 to 1:6 Glauber's Salt gms/lit 50 50 30% NaOH Soln. ml/lit 3-6 2-3 Soda Ash gms/lit 5 5 Trisodium Phosphate gms/lit 30 20-25 Dyeing at 600 C for 60 minutes final alkali addition. After-treatment Rinse in cold water, Hot rinse, soap at boil with 2 gm/l neutral detergent for 15 minutes, Hot rinse, Cold rinse & Dry.
  22. 22. 22 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- NOTES:  For T. Blue G. dyeing use 50 gms/lit Glauber's Salt for exhaustion and 15 to 20 gms/lit Soda Ash alongwith 3-5 gms/ lit NaOH (72°Tw) in last twc ends at 800C 'or fixation  For Reactive Yellow FG, Red C2G & Red 5B, 80 gms/lit Glaubers Salt gives better colour yield  In case or Reactive Brill. Blue R only 1 quarter of required Salt is added over first and second turn. The remaining Salt is added only after the addition of Alkali. REACTIVE DYES-TANACTIVE HE BRAND DYES DYEING PROCEDURE-DYEING METHODS - Winch, jet, package & beam dyeing machines. These dyes are specially designed for exhaust dyeing methods. The dyeing method selection depends upon the type of substrate to be dyed and the machinery to be used for dyeing. Depth of Shade Salt Unmercerised cotton(gm/l) Mercerized cotton or Viscose Rayon Soda Ash (gms/l) Fixation time (min.) Upto 0.10% 10 5 10 30 0.11-0.30% 20 10 10 30 0.31-0.50% 30 20 10 45 0.51-1.00% 45 30 15 45 1.01-2.00% 60 40 15 45 2.01-4.00% 70 55 20 60 Above 4.00% 90 65 20 60 Method No. 1: Salt addition in portions (suitable for mercerized yarn) This process is recommended for non-circulating liquor machinery and it is suitable for all depths of shade.
  23. 23. 23 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Method No. 2: Salt addition at start (Suitable for unmercerised yarn) This method is recommended for machines with liquor circulation and it is suitable for medium to heavy depth of shades. Method No. 3: Both salt & alkali addition at start The method is recommended for machines with liquor circulation, primarily for the dyeing of medium - heavy binary combinations. It is suitable for unmercerised cotton. Note 1: A mixture of soda ash and caustic soda is recommended alkali for this method. Depth of Shade Soda ash gms/l Caustic Soda 100% gms/l Upto 1.0% 5 0.2 1.01 to above 5 0.5 Method No. 4: (Dyeing Pale Shade) (Garment dyeing) The method is recommended for machines with microprocessor controlled addition system for dyeing pale shades (less than 0.5% depth) and for all shades on mercerized cotton & viscose packages
  24. 24. 24 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Method No. 5: Isothermal Method (Dyeing heavy shades garment) The method is recommended for machines with microprocessor controlled addition systems for medium to heavy depths (>than 0.5% depth) on unmercerised cotton. Dyeing method for Jigger machines- Due to high temperature dyeing the problems of off-shade selvedges of too pale selvedges are often encountered in dyeing with these machines. The following precautions hence should be taken to avoid such problems. 1. To use closed type jiggers so that a uniform temperature is possible across the width of fabric. 2. Batch the fabric evenly. 3. Maintain the dye bath at minimum of 85-90o C during salt stage. 4. Adjust the dye bath temperature 85-90o C to ensure that fabric is maintained at minimum 80o C during alkali addition stage. Procedure - Set the dye bath at 90o C with resist salt 2 gms/l. Now add 1/2 amt. of dye and run one end. Then add remaining 1/2 amt. & run another one end. Add 1/2 amt. of salt & run one end. Add remaining 1/2 amt. Of salt and run another end. Maintain 80o C temperature continue to run for 2 ends. Now add 1/2 amt. of soda ash & run for one end. Then add remaining 1/2 amt. Soda ash & run for another one end. Then add remaining 1/2 amt. soda ash & run for another one end. Then run for 4 ends or more if required & wash. (1 end =10 minutes) Dyeing method for cotton / polyester blend- The one bath two stage dyeing method for polyester / cotton blend is applicable on jet, beam or package dyeing machines. 2 gm/l Buffer pH 5 (5.5) X% GAAYACTIVE 'HE' dye 1 gm/l Anionic dispersant 50 gms/l Salt X% Disperse Dye 15 gms/l T.S.P. Soda ash
  25. 25. 25 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Salt and alkali requirements- Depth of Shade % on total weight of goods Salt (gms/l) Soda Ash (gms/l) Upto 0.2% 15 10 0.21-0.4% 20 15 0.41-0.80% 30 15 0.81-1.6% 50 20 Aabove 1.6% 70 20 Washing - off procedure- In order to obtain maximum wet-fastness properties, brightness and purity of shades with consistent dyeing results, it is essential to give a through 'Soaping' to clear-off unreached hydrolyzed dye form the dyed fabric. The dyed fabric is rinsed repeatedly in cold water to remove most of the alkali, salt and unfixed dye present and rinse again in warm water not higher than 60o C. then run in a bath containing: Anionic detergent - 1-2 gms/liter for 15 minutes at the boil. Then rinse in warm water (up to 60o C) and finally in cold water. The most satisfactory results in washing-off, particularly for piece goods, are obtained by employing an Open soaper or perforated beam-washing machine. If such equipments are not available, conventional ones like jig or winch may be used. For yarn in the hank form open-vat is employed and for yarn in packaged form the package-dyeing machine itself used. About Blend Dyeing: Blends are any textile material from fibre through yarn to fabric which are deliberate combinations of chemically or physically different fibrous polymer.cotton and Polyester blend is an example of chemically different blend and Cotton and Viscose is physically different blend because both are cellulosic. Object of Blending: 1. Dilution of an expensive, lusterious fibre by blending with cheaper substitute. 2. To incorporate of more durable component to extendthe useful life.e.g. Core spun yarn. 3. A compromise to take advantage of disirable performance characteristics, contribute by both fibre component.e.g. P/C blends to get comfort of cotton, strength and crease recovery of polyester. 4. The development of novel fabric design for garments incorporating multicolour effect.e.g. Polyester part is dyed and cotton part undyed.
  26. 26. 26 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- 5. The presence of attractive appearance using byy combination of yarn of different luster, crimp is possible by blending. 6. Colourant modification is possible by blending. 7. Finishing process modification. 8. Improved moisture absorption. 9. Reduce anstistatic characteristics pilling. Process Sequence of P/C Blend Dyeing: Desizing ↓ Scouring ↓ Drying ↓ Heat setting ↓ Mercerization ↓ Drying ↓ PET dye ↓ Reduction clearing ↓ Drying ↓ Singing ↓ Cotton dye ↓ Washing ↓ Soaping ↓ Washing ↓ Drying
  27. 27. 27 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Dyeing P/C Blend with Disperse and Vat Dye: Recipe: Disperse dye ----------------------------------------X% Vat dye-------------------------------------------------Y% Dispersing agent------------------------------------o.5-1% Wetting agent-----------------------------------------0.5-1% PH-------------------------------------------------4-5 with acetic acid(30%) Procedure: Prepar the bath with dispersing agent,wetting agent and acetic acid.Treatment for 10-15 minute at 50-60 degree C.Then add disperse and vat dye in the bath.Dyeing for 10-15 minute.Raise temp. up to 130 degree C in 60-90 minute.After PET part dyeing cool to 80 degree for proper levelling then add caustic and hydrose and dyeing 15 minute.Cooling to 60 degree c and dyeing for 30 minute for better exhaustion.Rinse with cold water and oxidation with hydrogen per oxide for 15 minute at 50 degree C.Then rinseing with cold water and soaping 95 degree c for 25 minute using 2g/l lissapol.Hot and cold rinse and then final wash off. Dyeing P/C blend with Disperse and Reactive Dye (Thermosol Process): Recipe: Disperse dye -----------------------------------X% Reactive dye ----------------------------------Y% Soda ash-----------------------------------------5-20g/l Migration inhibitor ----------------------------10-20g/l Wetting agent----------------------------------1-2g/l Dyeing Procedure: Padding: Padding with disperse and reactive dye at 20-30 degree C. Liquor pick up 60-80%. Predrying: Partial drying is done to avoid migration of dyes.Here keep m.c 25%. Drying: Complete and even dyeing at 110-150 degree C. Thermofixation: It's done at 180-220 degree C about 30-45 sec. to fixation dye.Polyester dyeing complete here Alkali Padding: Padding at 20-30 degree C.Pick up 50-60%.Caustic and salt used for Procion mx and Procion H. Steaming: Steaming is done 103-105 degree C about 30 sec. for procion mx and 45-75 sec.for procion H. Wash off: A typical 8 box wash off is given by Cold,hot water and detergent. Box-1:-------------------------------------water 60 degree C. Box -2&3:-------------------------------------Detergent 5 gm/l at boil Box-4&5:---------------------------------------water at the boil Box-7;-------------------------------------------water 60 degree C. Box-8:-------------------------------------------Cold water.
  28. 28. 28 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Classification of the methods for dyeing of P/C blend: Exhaust dyeing method or batch dyeing method- This is again classified in the following three groups- 1. Two bath dyeing 2. One bath one step dyeing 3. One bath two step dyeing method Thermosol Dyeing method - It is again classified in to two groups- 1. Continuous dyeing- 2. Pad batch process (semi-continuous) Note-In continuous dyeing process may be single bath or double bath. EXHAUST DYEING: Two bath dyeing 1. This is the process in which we have to dyed first polyester part in the HTHP beam dyeing machine or HTHP jet dyeing machine and the cotton part is dyed in the jigger machine. 2. Batch process 3. Machine used for dyeing of polyester part-  HTHP Beam dyeing machine( First commercialized HTHP machine)  HTHP jet dyeing machine 4. Machine used for dyeing of cotton part- 5. Jigger dyeing machine used
  29. 29. 29 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- PROCESS ROUTE P/C BLEND DYEING: MACHINE FOR POLYESTER DYEING: HTHP beam dyeing machine- No need to explain the whole process of dyeing in beam dyeing machine. Only some important points we will discuss about it- Advantages & features: 1. Loading and unloading of the fabric is easy and time of dyeing is short. 2. Dyeing in open width form. 3. Most suitable for those fabrics that might crease, extend or abrade when dyed in machines where the fabric is in motion. 4. Not appropriate for compact fabrics 5. De-aeration is essential to avoid paler dyed spots. 6. A wetting agent helps to eliminate air bubbles within the fabric roll. Recipe used HTHP dyeing:  Disperse dye- X%(depends upon the shade)  Dispersing agent-1g/l  Sequestering agent-1-2g/l(If required)  Defoamers -.5 to 1g/l  Levelling agent-.5 to 1 g/l  Wetting agent- .5g/l  Acetic acid-enough to get ph=5-6
  30. 30. 30 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Flow of the liquor usually in the in-to-out direction, but it can be reversed. Out-to-in flow can compress the material causing flattening and glazing, particularly on the inner layers.  Material stationary and liquor is moving.  Batching is very important; during batching tension should be uniform and optimum.  M:Lratio is 1:10  Both cloth and yarn can be dyed on this machine. Major Chemicals Used in Textile Wet Processing Introduction: Chemical analysis always involves the use of different chemicals. In order to assure accurate analysis results, the chemicals used need to be standardised, the procedures must be followed exactly and the data obtained have to be analysed statistically. If an instrument is used, it should be maintained and calibrated properly. In a chemical analysis, especially involving quantitative analysis, the amount of chemical used is critical and can be determined by the measurement of concentration if it is a solution, or by weight, if it is a solid. Sometimes, the concentration of a solution can be easily determined by using another known solution through titration. For acids and bases, if the concentration is sufficiently low, the pH concept is generally used to represent the concentration of the acid or base in the aqueous solution. For the analysis of common chemicals, such as caustic soda, acetic acid, soda ash, sodium dithionite, hydrogen peroxide, and so on, titrimetric analysis and gravimetric analysis are widely used. For the analysis of surfactants and other chemicals, qualitative spot tests and specialised instruments should be utilized. Before the analysis of chemicals in textile wet processing we should to know about concentration, titration, weighing, pH etc. Now a short identity of these is given below. Concentration: The concentration of a solute is usually expressed as the amount of a solute in a unit volume of a solution. The amount of a solute can be in grams (g), kilograms (kg), moles (mol), or normals (n). The unit volume of a solution is always in litres (l). Titration: Titration is a method by which the concentration of an unknown solution can be determined using a standardised solution with a known concentration through a stoichiometric reaction. The end point of the chemical reaction is indicated by the colour change of an indicator or an instrumental reading. The standard solution of a known reagent is the titrant and the unknown solution is the titrand. Weighing: Weighing is an important operation in gravimetric analysis. Usually it involves the use of an
  31. 31. 31 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- electronic balance with a minimum readability of 0.1 mg. In order to ensure reproducible results, sample handling is very critical especially when hygroscopic materials are weighed. pH: pH is a scale between 0 and 14 used to express the concentration of hydronium (H3O+, or H+) ions in a solution. It is defined by Equation. pH = – log [H+] Major Chemicals Used in Wet Processing: Acids, bases, salts, surfactants, oxidising agents and reducing agents are the major chemicals those are widely used in wet processing industry. Acid: An acid (from the Latin acidus/acēre meaning sour) is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and reacting with bases such as sodium carbonate. Aqueous acids have a pH under 7, with acidity increasing the lower the pH. Chemicals or substances having the property of an acid are said to be acidic.The following standard solutions are used in the acid analysis. They are usually prepared in advance and consumed within a certain period of time. 1. H2SO4, 0.1 N, 0.25N, 0.5 N and 1 N; 2. HCl, 0.1N, 0.25 N, 0.5 N and 1 N; 3. HNO3, 0.1 N; There are two types of acid 1. Inorganic acid 2. Organic acid Inorganic Acid: Inorganic acid are Sulphuric acid (H2SO4), Hydrochloric acid (HCl), Nitric acid (HNO3), Phosphoric acid (H3PO4), etc. Sulphuric Acid (H2SO4): The concentration of sulphuric acid (H2SO4) can be determined by using Baume’s (ºBé) hydrometer. The titration of sulphuric acid is carried out using sodium hydroxide in the presence of phenolphthalein as an indicator. The end point is reached when a faint pink color is persistent. HCl The concentration of hydrochloric acid (HCl) can be determined using a hydrometer, in a very similar manner to the determination of sulphuric acid concentration. Hydrochloric acid is a volatile acid at high concentration.
  32. 32. 32 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- HNO3 The concentration of nitric acid (HNO3) can be determined using a hydrometer. If titration is used to determine the concentration, phenolphthalein is the indicator. H3PO4 The concentration of phosphoric acid (H3PO4) can be determined in a similar manner to that discussed for H2SO4, HCl and HNO3. Organic Acids: Organic acids are HCOOH (formic acid), Acetic acid etc. HCOOH HCOOH (formic acid) is the simplest organic acid in terms of its organic structure. Concentrated HCOOH is usually 88% in strength. Since formic acid is a volatile acid, precautions should be taken to prevent loss of strength in the sample preparation stage. The concentration of formic acid can be determined by acid– base titration as well as by redox titration owing to the reduction power of formic acid. CH3COOH Acetic acid is a weak acid. It is available at different concentrations. Highly concentrated acetic acid at 98% and above is called glacial acetic acid because its freezing point range is between 13.3 ºC (98%) and 16.7 ºC (100%). Glacial acetic acid is flammable. The concentration of acetic acid can easily be determined using acid–base titration with phenolphthalein as an indicator. The water used should be free from CO2, prepared by boiling before use. Base: A base in chemistry is a substance that can accept hydrogen cations (protons) or more generally, donate a pair of valence electrons. A soluble base is referred to as an alkali if it contains and releases hydroxide ions (OH−) quantitatively.Bases are two types 1. Inorganic and 2. Organic bases Inorganic Bases: Inorganic bases are Sodium hydroxide (NaOH), Sodium carbonate (Na2CO3), Ammonium hydroxide (NH4OH) etc. NaOH Sodium hydroxide (NaOH) is also called caustic soda. It is available in solution at different concentrations or in solid form. Commercial NaOH often contains a little sodium carbonate (Na2CO3) as a by-product of the manufacturing process. This small amount of Na2CO3 will usually not influence its use in textile wet processes.
  33. 33. 33 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Owing to its strong alkalinity, NaOH can react with CO2 in air easily. It can also absorb water very quickly. Na2CO3 Sodium carbonate (Na2CO3) is also called soda ash. In textile wet processes, it is often available in anhydrous form. Its purity can be > 99% Na2CO3 (58% Na2O). If the concentration of a Na2CO3 solution needs to be determined, a titrimetric method identical to the ones listed for NaOH in this section can be used. If the existence of bicarbonate is a concern (very rarely in textile wet processes) the following method can be used to determine the content of bicarbonate in sodium carbonate. NH4OH Ammonium hydroxide (NH4OH) is a water solution of ammonia gas (NH3). It can also be called aqua ammonia or ammonia water. The concentration determination can be done using either a hydrometer or an acid–base titration. Since ammonia is volatile, the concentration determination should be done with care to avoid any loss of strength. If a hydrometer is used, the sample and the hydrometer should be cooled to 5–10 ºC. Table 4.75 lists the relationship between the concentration (% w/w) and ºBé of NH4OH at 10 ºC. Acid–base titration can also be used to determine the concentration of NH4OH. Organic Bases: Organic bases are Triethanolamine, N (CH2CH2OH) 3, Ethylenediamine (H2NCH2)2 etc. Triethanolamine Triethanolamine, N (CH2CH2OH) 3, is a strong organic base miscible with water, methanol and acetone. The pH of its 0.1N aqueous solution is 10.5. Analytical grade N(CH2CH2OH)3 is a highly hygroscopic and viscous liquid with a pale yellow or no colour. Its melting point is between 18 and 21 ºC. Its density is about 1.12. Ethylenediamine Ethylenediamine, (H2NCH2)2, is a strong organic base miscible with water and alcohol. It is a colourless and viscous liquid with a density of 0.898 and a melting point of 8 ºC. The pH of a 25% aqueous solution is 11.5. Like triethanolamine, it is an aliphatic amine soluble in water and, therefore, can be determined by the acid–base titration with methyl orange as an indicator. Salts Salts are the products of the acid-base neutralisation reaction. The salts used most in textile wet processes are common salt (NaCl, sodium chloride) and Glauber’s salt (Na2SO4, sodium
  34. 34. 34 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- sulphate). The content analysis of salts is usually conducted by using a precipitation titration method which may be followed by filtering and weighing procedures to obtain the final results. Sodium chloride Industrial grade NaCl has a content of 92–98%. The precipitation titration can be conducted using 0.1 N AgNO3 as the titrant and 5% K2CrO4 as the indicator (the Mohr method). The sample chloride solution should be buffered with calcium carbonate to a pH between 6.3 and 7.2 in order to avoid any interference from other ions present in the solution. Sodium sulphate Na2SO4 is available in two types, anhydrate and decahydrate. Its content analysis can be conducted based on the precipitation method using barium chloride (BaCl2). An excess amount of barium chloride is added into the sample solution which has been filtered beforehand to form BaSO4 precipitate as indicated by the following reaction: Na2SO4 + BaCl2 →2NaCl + BaSO4↓ Surfactants Surfactants are widely used in textile wet processes for the purpose of wetting, dispersing, emulsifying and cleaning. The molecular structures of surfactants have a distinctive hydrophilic moiety and a distinctive hydrophobic moiety. When they are used at a sufficient concentration, the surface/interface tension of the solution is lowered and micelles are formed, which give the solution extra properties. According to their ionic properties in aqueous solution, traditional surfactants can be divided into four categories: anionic, cationic, amphoteric and non-ionic. Surfactants are four types 1. Anionic surfactants , 2. Cationic surfactants, 3. Non-ionic surfactants and 4. Amphoteric surfactants Amphoteric surfactants: Amphoteric surfactants contain both anions and cations. They should show positive results when tested using either the basic methylene blue test for anionic surfactants or the alternative bromophenol blue test for cationic surfactants. A saturated bromine aqueous solution can also be used to determine the type of amphoteric surfactant. Add 5 ml of 1% sample solution to 1.5 ml saturated bromine aqueous solution.
  35. 35. 35 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Observe the colour of the precipitate. Heat the mixture and observe the change in the precipitate. If the precipitate is a yellow to yellow-orange colour and is dissolved to form a yellow solution after heating, the sample is an imidazoline or alanine type of amphoteric surfactant. If the precipitate is a white to yellow colour and insoluble after heating, the sample is the other type of amphoteric surfactant. Oxidising agents and reducing agents Oxidising agents are mainly used for bleaching and reducing agents are mainly used for vat dyeing in textile wet processes. These agents are often strong chemicals and need to be handled with care. The assay of these agents is almost always based on the redox titration. In a redox reaction, an oxidising agent (oxidant) is reduced (it gains electrons) and a reducing agent (reductant) isoxidised (it loses electrons). The redox reaction can be written as two half reactions shown below: Oxidation reaction: reducing agent → oxidized form + n e– Reduction reaction: oxidising agent + n e– → reduced form The net reaction is: reducing agent + oxidising agent → oxidised form + reduced form Oxidising Agents: Hydrogen peroxide Hydrogen peroxide (H2O2) can be titrated with potassium permanganate (KMnO4) in an acid medium. H2O2 is the reducing agent and KMnO4 is the oxidising agent. Sodium Hypochlorite In hypochlorite bleaching of textiles, active chlorine is the species measured for the control of the bleaching process. Iodometry is the method used to determine the content of active chlorine. Sodium perborate Either sodium permanganate or potassium iodide can be used to titrate the sodium perborate (NaBO3•4H2O). Dissolve 0.2 g of sample in 200 ml distilled water, add 40 ml 6 N H2SO4, and titrate with 0.1 N sodium permanganate until a pink colour appears. Reducing Agents: Sodium hydrosulphite (Na2S2O4) It is the Dilute of 10 ml 40% formaldehyde with 50 ml distilled water. Glucose Glucose (C6H12O6) can be used as a reducing agent in vat and sulphur dye applications. It can
  36. 36. 36 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- be analysed by iodometry. Accurately prepare a 0.5% glucose solution. Sodium thiosulphate Sodium thiosulphate (Na2S2O3•5H2O) can be titrated easily by iodometry. Accurately weigh a 5 g sample and dissolve it in 500 ml distilled water to make a 1% sample solution. Miscellaneous Chemicals Ethanol The specific gravity of ethanol (C2H5OH) is directly related to its content. Table 4.7 lists the relationship between the volume% (weight %) and the specific gravity of ethanol at 15 ºC. Ethylene glycol and glycerol ASTM method D161518 may be used to estimate the concentration of ethylene glycol and glycerol in an aqueous medium. Others Urea Urea is tested for the content of nitrogen using H2SO4 and formaldehyde. The indicator used is a mixed indicator containing 0.5 g phenolphthalein and 0.5 g thymol phthalein dissolved in 100 ml ethanol. A 25% formaldehyde solution used should be neutralised before use. The procedures of the method are briefly described below. 1. Dissolve 1 g fully dried sample in a small amount of water; add 3 ml concentrated H2SO4; mix well and heat on a hot plate. 2. Heat until the release of CO2 (bubbling) has stopped and dense white smoke (SO3) is emitted; leave to cool down. 3. Add 50 ml distilled water and 2 drops of methyl red indicator. 4. Neutralise the acidity of the solution with 6 N NaOH added dropwise until the red colour changes to a pink colour; add 0.5 N NaOH slowly to change the solution colour to a faint pink. 5. Add 40 ml 25% neutralised formaldehyde solution and 5 drops of the mixed indicator; stand for a few minutes. Fluorescent whitening agents Fluorescent whitening agents (FWA) are a special type of chemical that can significantly increase the apparent whiteness of treated fabrics. They absorb UV radiation and re-emit the absorbed energy in the blue visible light range which makes the treated fabrics appear whiter. The easiest test for the effect of FWAs is simply a visual examination of the whiteness of treated fabrics. Manufacturer’s recommendations should be followed in order to achieve the best whitening effect. Ethylenediamine tetraacetate (EDTA) Ethylenediamine tetraacetate (EDTA) can form a few different water soluble salts with calcium, potassium and sodium, for example, calcium disodium, trisodium and tetrasodium salts. EDTA tetrasodium salt is used most widely in many industrial applications as a powerful chelating
  37. 37. 37 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- agent. Its 1% solution has a pH of 11.3. It can chelate with many divalent and trivalent metal ions to form watersoluble metal complexes. HTHP BEAM DYEING MACHINE: Sectional diagram of a high-temperature beam dyeing machine Disadvantages of beam dyeing machine:  —Fabric of different width can not be dyed together on a single beam.  —The dyed fabric may be display moiré effect if it is tightly due to shrinkage.  —Uneven dyeing may occur if the beam is fully loaded, as the dye liquor has penetrate several layers of fabric. JET DYEING MACHINE:
  38. 38. 38 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- HTHP jet dyeing machine: The jet dyeing machine is an extension of the HPHT winch dyeing machine. Jet dyeing machine developed by BURLINGTON Industries and first machine developed in 1963 by Gaston country Machine co. of U.S.A Features:  Both material and liquor is moving.  Dyeing in rope form.  Fabric speed usually 200-250mt/min  The jet dyeing can usually operated up to 1400c under high pressure and having capacity capable of dyeing 100 to 150 kg of fabric at a time Chemicals added  Acids  Buffers  Sequestering agent  Anticrease agent  Defoamers  Levelling agent DEVELOPMENT IN JET DYEING MACHINE:  Soft flow jet- slow motion of fabric. Suitable for knitted fabric  Super jet dyeing machine- M:L is 1:1  Aerodynamic jet dyeing machine  Jet created by mixture of air + water  M:L is 1:1 , drain out at a 130c  Multi-nozzle sot flow jet dyeing machine Advantages of jet dyeing machine: 1. Fabric of two different width can be dyed at a time so that two lots can be combined together for dyeing. 2. No special batching device is required for winding the fabric as in beam dyeing. 3. There is no flattening effect or uneven dyeing on the fabric as in beam dyeing
  39. 39. 39 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Disadvantages: 1. There is possibility of entanglement of light-weight fabric during dyeing. 2. Loose fibres removed from the fabric may get redeposited on the fabric surface as well as on the interior of the jet dyeing vessel, this problem does not arise in beam dyeing. 3. Yarn can not be dyed in a jet dyeing machine whereas it can be dyed in a beam dyeing machine. PROBLEMS- 1. Foaming problem 2. Oligomers problem 3. Rope marks Machine used for cotton dyeing: Jigger dyeing machine  Open jigger or closed jigger dyeing machine-  Closed jigger specially for vat dyeing.  Liquor is stationary and fabric is moving.  500 t0 1000 meter of fabric is processed in one time.  M:L ratio in jigger dyeing machine is about 1:5.  Usually take 10 min. for each passage One bath two step dyeing- One-bath dyeing processes, using both the dyes such as following in the same dye bath. 1. Disperse and vat dyes. 2. Disperse and reactive dyes. 3. Disperse and direct dyes. Dyeing machine: Name of the m/c: Dyeing machine Brand Name: Dilmenlar Manufacturing Company: Turkey Year of Manufacturing: 2004 Machine capacity: 150 kg No. of nozzle: 02 Maximum Temperature: 135°c Motor: 01 Winch Motor: 01 Pump Motor: 01 Jigger dyeing machine Jigger dyeing machine is the most commonly used for dyeing all kinds of cotton fabric. There are mainly two types of jigger dyeing machine. One is open jigger dyeing machine and other is closed jigger dyeing machine. The open jigger dyeing machine is shown in the figure. This machine consists of V shaped stainless steel vessel. Two rollers are fitted above the vessel called as cloth rollers. These rollers are rotated by power. Out of these two rollers one roller is driven by a motor which is called take
  40. 40. 40 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- up roller and the other roller from which the cloth is delivered is called let off roller. When all the cloth is passed from the let off roller to the take up roller, it is called as one end or one turn. The number of ends or turns depends upon the type of the fabric and also the percentage of the shade. Jigger dyeing machine Initially, a large length of (50 kg) cloth is wound on the let off roller and take up roller is then driven by the power. After one end is taken, the take up becomes let off roller. These backward and forward movements of cloth through the dye liquor absorb more and more dye. The capacity of the jigger is 100 to 150 gallons. In the modern jigger, automatic devices are fitted along with the timing switch by using reversing will take place automatically. When dyeing all the dye liquor should not be added at one time. The dye liquor should be added in batch wise, in order to get even shade on the cloth. In the present scenario, closed types of jiggers are used. The main advantage is to prevent heat loss and chemical loses by evaporation. This type of jigger is very important for dyeing vat, Sulphur etc. Advantages of Jigger Dyeing Machine 1. The cloth can be dyed in open width form of full width form. 2. Chemical and heat loses are less when compared to winch dyeing machine 3. The material to liquor ratio is 1:3 (or) 1:4 which saves considerable amount of chemical cost and steam cost. Disadvantages of Jigger Dyeing Machine It exerts lot of tension in the warp direction and because of this normally woolen, knitted fabric, silk etc are not dyed in jigger dyeing machine. Modern Machinery Used in Dyeing Process: Modern dyeing machines are made from stainless steels. Steels containing up to 4% molybdenum are favored to withstand the acid conditions that are common. A dyeing machine consists essentially of a vessel to contain the dye liquor, provided with equipment for heating, cooling and circulating the liquor into and around the goods to be dyed or moving the goods through the dye liquor. The kind of machine employed depends on the nature of the goods to be dyed. Labor and energy costs are high in relation to total dyeing costs: the dyers aim is to shorten dyeing times to save steam and electrical power and to avoid spoilage of goods. Modern dyeing machine
  41. 41. 41 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- The conical-pan loose-stock machine is a widely used machine. Fibers are held in an inner truncated conical vessel while the hot dye liquor is mechanically pumped through. The fiber mass tends to become compressed in the upper narrow half of the cone, assisting efficient circulation. Leveling problems are less important as uniformity may be achieved by blending the dyed fibers prior to spinning. The Hussong machine is the traditional apparatus. It has a long, square-ended tank as a dye bath into which a framework of poles carrying hanks can be lowered. The dye liquor is circulated by an impeller and moves through a perforated false bottom that also houses the open steam pipe for heating. In modern machines, circulation is improved at the points of contact between hank and pole. This leads to better leveling and elimination of irregularities caused by uneven cooling. In package-dyeing machines dye color may be pumped in rather two directions: 1. Through the perforated central spindle and outward through the package or 2. By the reverse path into the outer layers of the package and out of the spindle. In either case levelness is important. Some package-dyeing machines are capable of working under pressure at temperatures up to 130C. The winch is the oldest piece of dyeing machine and takes its name from the slated roller that moves an endless rope of cloth or endless belt of cloth at full width through the dye liquor. Pressurized-winch machines have been developed in the U.S. In an entirely new concept; the Gaston County jet machine circulates fabric in rope form through a pipe by means of a high-pressure jet of dye color. The jet machine is increasingly important in high-temperature dyeing of synthetic fibers, especially polyester fabrics. Another machine is the jig. It has a V-shaped trough holding the dye color and guide rollers to carry the cloth at full width between two external, powered rollers, the cloth is wound onto each roller alternately, that is, the cloth is first moved forward, then backward through the dye color until dyeing is complete. Modern machines, automatically controlled and programmed, can be built to work under pressure. It was found that in using Winch machines, there were some inherent problems. So the Jet dyeing machines when they came up in the 1970’s were specifically designed to overcome those shortcomings. In the Jet dyeing machine the reel is completely eliminated. A closed tubular system exists where the fabric is placed. For transporting the fabric through the tube a jet of dye liquor is supplied through a venturi. The Jet creates turbulence. This helps in dye penetration along with preventing the fabric from touching the walls of the tube. As the fabric is often exposed to comparatively higher concentrations of liquor within the transport tube, so little dye bath is needed in the bottom of the vessel. This is just enough for the smooth movement from rear to front. Aqueous jet dyeing machines generally employs a driven winch reel along with a jet nozzle. The following diagram explains the functioning of a Jet dyeing machine:
  42. 42. 42 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Types of Jet Dyeing Machine: In deciding the type of dyeing machine the following features are generally taken into consideration for differentiating. They are the following. Shape of the area where the fabric is stored i.e. long shaped machine or J-box compact machine. Type of the nozzle along with its specific positioning i.e. above or below the bath level. Depending more or less in these criteria for differentiation following types of Jet Machines can be said to be as developments of the conventional jet dyeing machine. 1. Overflow Dyeing Machine 2. Soft-flow Dyeing Machine 3. Airflow Dyeing Machine Advantages of Jet Dyeing Machine: The Jet Dyeing Machine offers the following striking advantages that make them suitable for fabrics like polyesters. 1. Low consumption of water 2. Short dyeing time 3. Can be easily operated at high temperatures and pressure 4. Comparatively low liquor ratios, typically ranges between 1:4 and 1:20 5. Fabrics are handled carefully and gently Soft Flow Dyeing Machine: In the soft flow dyeing machine water is used for keeping the fabric in circulation. The conceptional difference of this equipment from a conventional jets that operates with a hydraulic system is that the fabric rope is kept circulating during the whole processing cycle (right from loading to unloading). There is no stopping of liquor or fabric circulation for usual drain and fill steps. The principle working behind the technique is very unique. There is a system for fresh water to enter the vessel via a heat exchanger to a special interchange zone. At the same time the contaminated liquor is allowed channel out through a drain without any sort of contact with the fabric or for that matter the new bath in the machine. Key Features of Soft flow Dyeing Machine:  Significant savings in processing time.  Savings in water that is around 50%.  Excellent separation of different streams results in optimum heat recovery and a distinct possibility of further use or a dedicated treatment.
  43. 43. 43 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Principle of Soft Flow Dyeing Machine: Textile material can be dyed using batch, continuous or semi continuous process. Batch processes are the most common method used to dye textile materials. There are three general types of batch dyeing machines: 1. In which fabric is circulated 2. In which dye bath is circulated 3. In which both the bath and material is circulated. Jet dyeing machine is the best example of a machine that circulated both the fabric and the dyebath. Jet dyeing is used for knitted fabrics. For Terry-towels soft flow dyeing is use. In jet dyeing machine the fabric is transported by a high speed jet of dye liquid. As seen in the figure, this pressure is created by venturi. A powerful pump circulates the dyed bath through a heat exchanger and the cloth chamber. Cloth guide tube helps in circulation of fabric. Types of Soft Flow Dyeing Machine: A few of the commercially popular brands along with their particular technical specifications are discussed here. The categories are not exhaustive as such. Multi Nozzle Soft Flow Dyeing Machine: Technical Features: 1. Very low Liquor ratio - around 1:1 (Wet Fabric) 2. Can reach high temp. up to 140°C 3. Easily dye 30 to 450 g/mt.sq. of fabrics (woven & knitted fabrics) 4. Number of very soft-flow nozzles 5. No pilling effect 6. Wide capacity
  44. 44. 44 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Multi Nozzle Soft flow Dyeing Machine High Temperature High Pressure Soft Flow Dyeing Machine: Technical Features: 1. Compact body made of stainless steel. 2. High efficiency heat exchanger for quick heating/cooling. 3. Compact body made of stainless steel. 4. Heating rate - around 4°C/Min upto 900°C - around 3°C/Min upto 135°C At steam pressure of 6 Bar. 5. Cooling Rate- around 4°C/ Min At water pressure of 4 Bar and 15°C. 6. Maximum working temp is 135°C. 7. Maximum working pressure of 3.2 Bar. 8. Control manual as well as automatic. 9. Heavy duty stainless steel pump. Soft Flow Dyeing Machine 1. The vigorous agitation of fabric and dye formulation in the cloth increases the dyeing rate and uniformity. It minimizes creasing as the fabric is not held in any one configuration for very long. The lower liquor ration allows shorter dye cycles and saves chemicals and energy. 2. In soft flow dyeing machines the fabric is transported by a stream of dye liquor. However, the transport is assisted by a driven lifter reel. 3. These machines use a jet having lower velocity that that used on conventional jet dyeing machines. 4. The soft flow machines are gentler on the fabric than conventional jet machines.
  45. 45. 45 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Winch dyeing machine A dyeing machine consisting essentially of a dye vessel fitted with a driven winch ( usually above the liquor level) which rotates and draws a length of fabric, normally joined end to end, through the liquor. Winch dyeing machine Winch dyeing machine is a rather old dyeing machine for fabrics in rope form with stationary liquor and moving material. The machine operates at a maximum temperature of 95-98°C. The liquor ratio is generally quite high (1:20-1:40). Winch dyeing machines are a low cost design that is simple to operate and maintain, yet versatile in application proving invaluable for preparation, washing or after treatments as well as the dyeing stage itself. In all winch dyeing machines a series of fabric ropes of equal length are immersed in the dye bath but part of each rope is taken over two reels or the winch itself. The rope of fabric is circulated through the dye bath being hauled up and over the winch throughout the course of the dyeing operation. Dyestuff and auxiliaries may be dosed manually or automatically in accordance with the recipe method. A winch dyeing machine Description and Dyeing Method on Winch Dyeing Machine The basic principle of all winch dyeing machines is to have a number of loops or ropes of the fabric in the dye bath, these ropes are of equal length , which are mostly immersed in the liquor in the bath. The upper part of each rope runs over two reels which are mounted over dyebath. At the front of the machine, above the top of the dye liquor , is a smaller reel, which is called jockey or fly roller. The fly roller remains free wheeling along with fabric rope. At the back of winch tank is the winch wheel, which pulls the fabric rope from the dye bath over the jockey reel for dropping in the dye bath for immersion. From the dropped location, the fabric rope travels back. To be lifted and fed to winch wheel.
  46. 46. 46 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- The dyeing process on winch dyeing machines is based on higher M:L as compared with other dyeing machines. The process is conducted with very little tension. The total dyeing time is lengthier as compared to other machines. Advantages of Winch Dyeing Machine 1. Construction and operation of winch are very simple. 2. The winch dyeing machines are suitable for types of wet processing operations from desizing to softening. 3. The winch dyeing machine is suitable for practically all types of fabrics, which can withstand creasing in rope form processing. 4. Thr tension exerted on winch is less than jigger dyeing machine,the material thus dyed is with fuller hand. 5. The appearance of the dyed goods is clean and smooth on winch dyeing machines. Limitations of Winch Dyeing Machine 1. Batch dyeing operations needs trimming, sewing, opening out the rope , loading and unloading for individual lots separately. 2. Since several lengths of fabric are run over the winch reel into the liquor and sewn end to end,Continuous length processing is not possible in a single batch. 3. Fabric is processed in rope form which may lead to crease marks, particularly in heavy , woven , thin and light synthetics. 4. Most of the machine works under atmospheric conditions Jet Dyeing Machine This is the most modern machine used for the dyeing of polyester using disperse dyes. In this machine the cloth is dyed in rope form which is the main disadvantage of the machine. In this machine, the dye tank contains disperse dye, dispersing agent, leveling agent and acetic acid. The solution is filled up in the dye tank and it reaches the heat exchanger where the solution will be heated which then passed on to the centrifugal pump and then to the filter chamber. Jet Dyeing Machine The solution will be filtered and reaches the tubular chamber. Here the material to be dyed will be loaded and the winch is rotated, so that the material is also rotated. Again the dye liquor
  47. 47. 47 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- reaches the heat exchanger and the operation is repeated for 20 to 30 minutes at 135o C. Then the dye bath is cooled down, after the material is taken out. Metering wheel is also fixed on winch by external electronic unit. Its purpose is to record the speed of the fabric. The thermometer, pressure gauge is also fixed in the side of the machine to note the temperature and pressure under working. A simple device is also fixed to note the shade under working. Advantages Jet Dyeing Machine  Dyeing time is short compared to beam dyeing.  Material to liquor ratio is 1:5 (or) 1:6  Production is high compared to beam dyeing machine. Disadvantages Jet Dyeing Machine  Cloth is dyed in rope form  Risk of entanglement  Chance for crease formation. Package dyeing machines Package dyeing machines are the most widely used now a days for dyeing of almost all type of yarns ,due to economical ,automatic and accurate dyeing results. The term package dyeing usually denotes for dyeing of any type yarn wound on the compressible dye springs/perforated solid dyeing tubes or cones. Yarn dyeing in package form is done at high temperature and under high pressure ,with the packages mounted on hollow spindles .These spindles are fixed on the dyeing carriers ,which is inserted into the dyeing vessel after closing the lid of the machine ,the dyeing liquor is forced through the packages in two way pattern (inside to out and outside to in) and goes on circulating throughout the vessel and yarn. Heat is applied to the dye liquor to achieve the dyeing temperature, time –temperature and flow reversal are controlled through a programmer. Package Dyeing Machine A series of technical developments in the recent years has resulted into package dyeing being developed into a highly sophisticated as well as an economic process. Latest design Package Dyeing machines are amenable to accurate control and automation. These features would likely
  48. 48. 48 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- to lead to increases in the application of package dyeing. The term package dyeing usually denotes for dyeing of yarn that has been wound on perforated cores. This helps in forcing the dye liquor through the package. With the start of dyeing cycle, the dye liquor goes on circulating throughout the vessel and tank. This happens till all the dye is used up or fully exhausted. The dye flows through to the yarn package with the help of the deliberate perforations in the tube package. Once full exhaustion is brought about, the carrier of coloured yarn is consequently removed from the vessel. A large centrifuge removes excess water from the packages. Finally the yarn is dried using an infra red drying oven. The image shows the process working of a Package dyeing machine. Working Process of Package Dyeing Machines The material to be dyed is wound on the dye springs, perforated plastic cheeses or steel cones and loaded in the carrier spindles ,which are compressed and bolted at the top to make a uniform and homogeneous dyeing coloumn. The liquor containing dyes chemical and auxilliaries is forced through with the help of pump, and circulated through the material from inside –out and is reversed periodically so that each and every part of the material get the same and uniform treatment. The dyeing cycle is controlled through a micro computer and different chemicals may be added through the injector pump or color kitchen at any stage of dyeing. In case of fully flooded machines ,the liquor expands with the rise in temperature (approximately 5% volume increases from 30-130 degree centigrade temperature) is taken back in the expansion tank through a back cooler. This extra water is then again injected to the dyeing vessel through an injector pump. Expanded volume of the dye liquor is thus remains in continuous circulation in the system. Any type of addition can be done to the machine through the injector pump, the quantity and time of injection can be controlled through the programmer. In case of air pad machines ,the air above the liquor acts as a cushion ,which is compressed with the increase in liquor volume, the pressure is controlled by pre set pressure control valve .In air pad machines have an advantage ,that entire dye liquor participate in dyeing and dye exhaustion is perfect. In case some addition has to be done in air pad machines , if the machine temperature is less than 80 degrees ,the liquor is taken back by back transfer valve to addition tank ,and injected back to machine vessel. If the machine temperature is above 80 Degree then cooling has to be done to bring down the machine temperature. Air pad technology is possible in all types of machines such as vertical kier, horizontal kier and tubular dyeing machines. The material after dyeing is washed and finished properly in the same machine and taken out hydro extracted or pressure extracted in the same machine and dried subsequently. Advantages of Package Dyeing machine Package dyeing methodologies have been subjected to intensive research and development. As a result package dyeing machine has evolved into a very sophisticated apparatus. It offers a number of advantages.
  49. 49. 49 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Package Dyeing Machine  Considerable reduction in yarn handling.  Compatible to automatic control, in the process leading to reproducible dyeing‟s.  Open to large batches.  High temperature dyeing a possibility.  Low liquor ratios, giving savings in water, effluent and energy.  Uniform and High rates of liquor circulation, that leads to level application of dyes. Machinery totally enclosed resulting in good working conditions at the dye-house. Types of Package Dyeing Machines Different type of Package Dyeing Machines are 1.Vertical Kier Dyeing Machines 2.Horizontal Kier Dyeing Machines 3.Tubular Dyeing Machines Vertical Kier Dyeing Machines These machines have a vertical cylindrical dyeing kier, in which material loaded into carriers with vertical perforated spindles, is dyed .The machine could be fully flooded or air pad type .These are high pressure machines and suitable up to 1350C temperature dyeing. Horizontal HTHP Dyeing Machines These machines are similar to vertical type machines in which the cylindrical dyeing kier is in horizontal position. The dyeing carriers with vertical spindles are used in these machines, which are inserted into the machine via trolleys. These machines are erected at the ground level and hence do not needs an overhead hoist as well as platform, thus making the dye house design and layout is simple. Tubular HTHP Dyeing Machines These machines may be of vertical or horizontal type, and have one or many tubes acting as small dyeing vessels, each with a single individual spindle. The spindle is taken out of the tube, loaded and then inserted back into it. These machines can be operated either fully loaded tubes or to partial loads by using dummies. Since all individual tubes in a machine are connected and serviced by a main pump, therefore it is also possible to operate as many tubes as required and disconnecting others. These machines can be erected at ground level and hence do not need a platform or hoist. These machines are most flexible as for as the capacity variation is concerned ,without altering the material to liquor ratio.
  50. 50. 50 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Hydro Extractor: Hydro-Extractors are also called Centrifuges. Centrifuges are used for water extraction (dewatering, pre-drying) of textile materials. Values of approx. 15% for residual moisture content can be achieved depending on the type of textile fiber. Centrifuges with perforated drums or baskets (Ø up to approx. 2000 mm) which oscillate vertically in ball-and-socket joints suspended on three points are produced in various designs as pendulating, suspension, cage and vertical centrifuges, also with so called gliding support bearings as gliding support centrifuges or in horizontal resp. vertical arrangements as open-width, horizontal and warp-beam centrifuges, etc. Most centrifuges have electric drives for speeds of approx. 750–1200 rpm and are generally provided with automatic control over various ranges. For safety reasons, an interlocking lid is essential on a centrifuge so that the motor cannot be started until the lid is locked, nor the lid raised until the basket is stationary again after the machine has been stopped. Hydro Extractor When used for dewatering loose stock, the cake of loose fibers is transferred from the dyeing machine to the centrifuge and hydro-extracted before it is run into the fiber opener as a preliminary stage of drying in a perforated drum drier. If an immersion centrifuge is used, impregnation of the loose fibers with a spinning lubricant is also possible. In this case, the material is loaded into the centrifuge, liquor is then pumped in (until it covers the material), and the goods are finally hydro-extracted. The advantage of such a procedure lies in the fact that a separate treatment of the textile material in an impregnation vat and the reloading of wet goods into the centrifuge are eliminated . Impregnation of textile material in the impregnation basket of a centrifuge is generally quicker and more effective for all processes than in a vat. The centrifugal force which drives the liquor through the goods during centrifuging accelerates penetration. It is possible to carry out several processes one after the other in an immersion centrifuge. In this case, however, separate drain channels and liquor tanks must be provided. The basket of an immersion centrifuge has an outer casing without perforations which surrounds the cylindrical basket of a normal centrifuge (extended conically at the top). By this means, it is possible to fill it with liquor to the level of the upper rim. Only when the basket is set in motion
  51. 51. 51 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- does the liquor, which is driven outwards by centrifugal force, rise up the basket casing and run over the upper rim. Loose fiber material (loose stock) can also be centrifuged continuously. For the dewatering of yarn packages, other possible options besides the asymmetrical dewatering of columns of yarn packages in suitably shaped compartments of the centrifuge include symmetrical dewatering by the rotation of individual packages or columns of yarn packages which involves less risk of package deformation. Technical Data: 1. Working width 1300mm 2. Machine speed 5~30M/min 3. Machine for the hydro extractor, softener, air ballooning type of cotton knitted tubular fabrics without tension, with fabrics entwisting, air balloon, control of the squeezing pressure and control of the final width of the fabric. 4. Automatic control of the feeding without tension, no edge mark, final folding without stretching. Versions with simple or double squeezing and imbuing with softeners. Advantages of Hydro Extractor:  No deformation of the packages.  Excellent rewinding properties. Rewinding can even be eliminated in a lot of cases.  Low residual moisture.  Even humidity distribution through the package.  Low energy consumption.  Dyeing tubes last longer.  Processes many different size packages.  Operator of centrifuge can also load dryer.  Maintenance-free brakes.  Closed system for effluent.  Low compressed air consumption.  Significant energy savings. HTHP Beaker Dyeing Machine HTHP Beaker Dyeing Machine is ideally suitable for sample dyeing of fabric and yarn at high temperature and pressure. This machine is a versatile, compact and maintenance free apparatus suitable for both Polyester and cotton sample dyeing. In fact it is suitable for dyeing of any fiber in form. The apparatus is of immense use for dyeing and processing units research/testing labs, textile engineering institutes and dyes manufacturers.
  52. 52. 52 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Beaker Dyeing Machine Features of HTHP Beaker Dyeing Machine: 1. The machine comprises of tank, beaker and gear box 2. The beakers are capable of withstanding pressure upto 6.0 Kg/cm square. 3. The machine is complete in stainless steel 4. Ensures a sound free and smooth working. 5. Microprocessor based programmer is provided which ensures temperature control. 6. Promises long life and leak proof service even after many years of use. Specifications of HTHP Beaker Dyeing Machine:  Standard Model : 12x250 ml., 12x100 ml., 6x500 ml., 12x500 ml.  Electric Supply : Single phase 220 Volts, AC Supply  Heater Supply : 3000 watt Single Phase  Overall dimensions of the Unit : 700 ±05mm (L) x 470±05mm (H) x 370±05mm (W)  Capacity of Beaker: 250 ml Beaker X 12 Pcs.  Carriage Rotation: At 22 rpm. (±2 rpm)  Maximum operating Temperature: 135°C.  No. of Heater : 3 x 1500 W  Maximum rate of heating: 1.50C  Maximum rate of cooling 1.50C ( Water temperature max 250C )  Net Weight of the Unit: 35 Kg.  Net Weight of the Beaker (250ml): 10.980 Kg.  Motor : Reversible Synchronous Geared Motor  Medium used for Heating : Glycerine  Beakers : 12x250 ml., SS-316 grade Working Principle of HTHP Beaker Dyeing Machine: 1. First of prepare for dyeing piece by taking the sample fabric as per leakier ratio as suggested by your quality consultant. 2. Sample moves up & down with auto forward and reverse direction through process controller. 3. The machine must be cleaned at the regular intervals by changing water inside the chamber.
  53. 53. 53 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- 4. All bearings should be lubricated every three months. 5. Single phase motor contacts and Power contacts should be inspected every three months Skein Dyeing Machine This is the most suitable machine for dyeing delicate yarns (Silk, Bemberg, etc.) since it prevents the material being too tightly packed; in fact other skein dyeing systems frequently produce an excessive packing of the dyed material. The machine is equipped with horizontal arms perforated in the upper part; skeins are stacked and suspended on this rack. The liquor, forced through the arm holes, penetrates the skeins and is then collected in an underlying vat. Standard machines are equipped with a rod which moves the skeins at preset times, changing the bearing point to obtain a more uniform dyeing. During the skein motion, the flow of the liquor is stopped to avoid the formation of tangles in the yarn; since yarns are not fixed to rigid supports, they can thoroughly shrink. This machine does not run under pressure. It is possible to dye at steady temperatures since the liquor is contained in a separate tank. Skein Dyeing Machine Modular skein dyeing machine with pullout arms. Pullout arms also allow the loading and unloading of skeins far from the dyeing machine, without manually intervening in the
  54. 54. 54 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- intermediate dyeing, squeezing and drying operations. It can be used for silk, cotton, viscose and Cashmere yarns. The operating costs of this machine are generally very high because it require a very high liquor ratio (1:15. 1:25. 1:30). Standby times for loading and unloading operations are also very high and the arms must be often cleaned. This machine can be used also for scouring and finishing processes. Some machine manufacturers have designed machines with slant covers to avoid unwanted liquor dripping on the skeins; the skein rotation is determined by the perforated arms, and not by the rotation of the skein-lifting device when the arm is stopped; it is therefore possible to eliminate the sliding contact with the skeins and preserve them perfectly. There are also package dyeing machines with triangle-shape arms, arranged radially on a variable-speed rotor. When the dyeing process has terminated, the material can be centrifuged and dried, by forcing a hot air flow into the arms and through the skeins. Equipment used in wet processing lab: Wet Processing Lab: Wet processing lab plays a vital role in the quality control of wet processing department. In every wet processing lab mainly three types of tests are performed. 1. Tests for determination of the acceptability of chemicals for their intended purposes. 2. Tests for determination of several physical properties of the material. 3. Tests for determination of the quality of he finished materials. 4. Tests for determination of the quantity of dyes & chemicals required for a particular order. When a new order is found; then the formulation of quantity of dyes & chemicals are prepared in the wet processing lab. According to the recipe at first lab dyeing is done. If the obtained shed is ok then sample dyeing is done in the floor. During sample dyeing different options are prepared by slightly altering the quantity of dyes & chemicals. The sample is sent to the buyer for approval. Buyer approves any one of the multiple options. Finally the recipe of the approved sample is taken for bulk production. After production the bulk is tested in the wet processing lab in order to ascertain wheatear the finished products are confirming the requisite quality or not. The instruments used in the dyeing lab are enlisted bellow with their purposes: 1. Oven: Used for drying samples. It dries any sample by using micro wave. 2. Thermostatic Water Bath: Used for extraction test. The samples are kept in Weing Bottle & are heated at required temperature by this instrument. 3. Tear strength tester: Used for testing the tear strength of sample (towel). Two samples from warp & two samples from weft are tested & the average tensile strength of sample in warp & weft direction is
  55. 55. 55 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- reported separately. 4. Crock Meter: Used for testing the rubbing fastness of sample. The sample is clipped in the sample stand & a staining fabric is clipped in the nose. Then the nose is rubbed against the sample for 10 times. At first rubbing is done in wet condition, then again rubbing is done in dry condition with another piece of staining fabric. Then the staining fabrics are assessed with standards & a grade is assigned to the sample. 5. PH Meter: Used for testing the PH of any solution. The PH meter is calibrated at first by using standard solution. Then the sensor is dripped in to the solution that’s PH should be tested & the reading of PH is shown on the display. 6. Hot Air oven: Used for drying sample by using hot air. 7. Absorbency Tester: Used for testing the water absorbency of towel. 8. Color Fastness Tester: This instrument is used for three distinct tests. These are: a. Color Fastness to Wash. b. Color Fastness to Perspiration. c. Phenolic Yellowing Test. This test is done in order to find out the presence of hazardous component in the poly bag. 9. Oscillating Dyeing M/C Used for lab dyeing in exhaust process. 10. Geyser: Used for heating water at desired temperature that is used for various tests. It is provided with separate pipes for feed & delivery of water. As it is mounted at a higher level so hot water can easily be supplied due to gravity force. 11. Horizontal Padding Mangle: It is a lab dyeing m/c of cold pad type. In this m/c the padding rollers remain horizontally; therefore it is called Horizontal Padding Mangle. This m/c is used for sample dyeing. For dyeing any sample at first the mangle is washed with water. Then dye liquor is taken to the bath. Then towel sample passes through the liquor & then through the squeezing rollers. Then the sample is kept covered with polybag for 12 hrs. Then the liquor is drained out & the m/c is washed again with water. 12. Launder-O-Meter: Used for assessing color fastness to non chlorine bleach. 13. AATCC Washer: Used for washing any sample. 14. AATCC Dryer: Used for drying samples. It dries the given sample in tumbling process in association with hot
  56. 56. 56 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- air. 15. Tensile Strength Tester: It is used for testing the tensile strength of sample. The Grab Test Principle is used in this m/c. The m/c is provided with two jaws; one fixed (bottom jaw) & another movable (top jaw). The sample is clumped between two jaws & then the m/c is started. As the distance between two jaws increases; eventually the sample breaks. Tensile strength of the sample is shown on the digital display in kg unit. Two samples from warp & two samples from weft are tested & the average tensile strength of sample in warp & weft direction is reported separately. 16. Hardness Test Kit: It is used for testing the degree of hardness in water. 17. Fume Hood: This m/c has just taken in to the wet processing lab & yet it has not been erected. It is used for testing different properties of dyes & chemicals. 17. Light Box Area: It is used for finding out deviation of shed between the batch & reference. Here a dyed sample is checked in the specific light recommended by buyer. The dyed sample is placed on the observation board that inclines at 45o angle. Then it is compared either with reference fabric or with reference pantone no. in the recommended light source visually. The following light sources are usually recommended by the buyers:  D-65  TL-84  UL-35  UL-30  CWF Except the enlisted instruments, many other simple instruments that are used in chemistry lab; are also used in wet processing lab. Those are enlisted bellow: 1. Beaker 2. Burette 3. Pipette 4. Glass Rod 5. Test Tube 6. Digital Balance etc 7. Decicator 8. Wine Bottle etc. KNOWLEDGE IS POWER SAYED
  57. 57. 57 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- DISPERSE/REACTIVE DYEING SYSTEM: Disperse/vat dyeing system: Typical dyeing recipe  Disperse dye-X%  Vat dye-Y%  Dispersing agent-.5-1%  wetting agent-.5-1%  pH 4-5 with acetic acid (30%) Procedure- Prepare the bath with dispersing agent, wetting agent and acetic acid + treatment for 10-15min at 50-60°c then + disperse and vat + dye for 10-15min + raise temp up to 130°c in 60-90 min. After PET part dyeing cool to 80c for proper levelling then add NaOH & Na2S2O 4 + dyeing 15min + cooling to 60°c + dyeing for 30 min. for better exhaustion Rinse with cold water + oxidation with H2O2 for 15min at 50°c + Rinsing with cold water + Soap at 95° C for 25 min using 2 g/l Lissapol D + Hot and cold rinse and then final wash off. Only vat dyes which are stable up to 130°c can be used for this process. One bath two step dyeing method- All vat dyes may be used for the one –bath high temperature process provided that the dyes are finely divided enough. The IK vat dyes are not preferred because the dye liquor requires to be cooled to about 300c in order to obtain full colour yield. Therefore when IK dyes are to be used it is preferable to dye by the two-bath process. Typical dyeing recipe-  Disperse dye-X%  Vat dye-Y%
  58. 58. 58 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id-  Dispersing agent-0.5-1%  Wetting agent-0.5-1%  Ph-4-5(attained with 1-2 ml/l of 30% acetic acid) Oxidation and soaping: Oxidation and soaping can be be achieved simultaneously using the following recipe:  Hydrogen peroxide(35%) 1-2 ml  Anionic detergent -.5-1g/l  Ph-9-10 First treat the material for 10-15 min. at 500c with hydrogen peroxide. Then the anionic detergent and raise the temperature to 950c. Soap for 10-15 min.  Method is used when selected vat dyes severely. It stain PET component during high temp dyeing.  Vat dye is added at 80°c after PET part dyeing rather than adding at the start with disperse dye.  Except it the whole process is same as the dyeing in one bath one step. DISPERSE/REACTIVE SYSTEM Same as one step dyeing except the addition of reactive dye at 80°c. This process is used for the reactive dyes which are not stable up to 130°c, due to which they can not be used in one step process Thermosol Dyeing method:  Continuous dyeing.  Pad batch process. Advantages of Thermosol dyeing-  Continuous process so it gives higher production.  Dye utilization is excellent.  Dye can be used afterward.  No carrier is required.  Fabric is processed in open width form so natural feel of fabric do not get disturbed.  No crease formation.  Lower energy is required than batch.  No extra heat setting is required
  59. 59. 59 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- Disperse/vat dye system- PDPS method (Continious method) ONE BATH ONE STEP THERMOSOL DYEING WITH DISPERSE AND REACTIVE DYES:
  60. 60. 60 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- CHEMICAL RECIPE & PROCEDURE: Chemical recipe-  Disperse dye-x g/l  Reactive dye-y g/l  Sodium bicarbonate or soda ash-5-20g/l  Urea-100-200g/l  Migration inhibitor-10-20 g/l  Wetting agent- 1-2g/l PROCESS-pad-dry-thermosol-cool-wash: 1. PADDING  Padding Temp-20-300 c  Liquor pick up-60-80% 2. DRYING  First partial drying in infrared pre dryer and then fully drying.  Partial drying is done to avoid migration of dyes.  Drying is done at 120°c. 3. THERMOFIXATION  It is done at 180-220°c, 30-45sec  It is the fixation step. 4. PADDING  Padding bath contain NaOH + Na2S2O4 5. STEAMING  During this vat dye penetrated inside the cotton part. Then oxidation, soaping and finally washing. One bath one step dyeing process-Disperse/Reactive dyes:  Padding in the second step is done using NaCl + NaOH  H- Brand reactive dye is used.  Fixation is done during steaming with saturated steam (102°c) for 30-60 sec.  Then washing, soaping and again washing. Recipe-  Disperse dye-x g/l  Reactive dye-yg/l  Sodium bicarbonate or soda ash-5-20g/l  Urea-100-200g/l  Migration inhibitor-10-20 g/l  Wetting agent- 1-2g/l.
  61. 61. 61 Engr. Abu Sayed, M.Sc in Textile Engineer, Email id- NEW APPROACHES OF DYEING OF P/C BLEND FABRIC-  Dyeing with Reactive Disperse Dyes in Supercritical carbon oxide.  Dyeing of 80/20 PET/COTTON blend by using azeotropic solvent.  Polyester/cotton blend fabric with sulphatoethyl sulphone disperse /reactive dye treatment.  One-bath dyeing PET/COTTON blend with azohydroxypyridone disperse dye containing a fuluorosulfonyl. Dyeing with Reactive Disperse Dyes in Supercritical carbon oxide: What is supercritical CO2?  It is a naturally occurring that is chemically inert, physiologically compatible, and relatively inexpensive.  It is nonflammable, it is supplied either from combustion process or volcanic process without the need of producing new gas & it is recycled in a closed system.  No disposal problem.  Easy to handle.