Mercerizing machine is a process for increasing absorbency, strength, and lustier of the fabric by physio-chemical treatment. And this chemical treatment is occurred in two IMP-1 and IMP-2 bath by passing the fabric into a airing zone. John Mercer, a person was the first chemist in the world who found this phenomenon in 1844.Therefore the process of this type of wet processing was called Mercerizing.
Objectives of Mercerizing Machine
To make the goods more luster because raw cotton fibers are ribbon-like. After this process, the fibers change to cylindrical shape, resulting more evenness reflected light from the goods.
To improve dye ability of the goods about 5-10%.
Specification of Mercerizing Machine
- M/c name: Mercerize m/c
- Brand: Goller
- Origin :Germany
- Speed:60 m/min
- Capacity :1 lac m/day
- Expander roller: Remove dirtness and keep the fabrics in level Padder Upperb padder: made by rubber Check hardness : 80-90%, Lower padder: made by AUTO Check hardness : 100%
- Dancing roller: Tension keeps proper before going on dryer.
- Caustic temperature : 35-55’C
- Vacume pump(air): Remove water
- Padder pressure: 3bar-washing, IMP-1 & IMP-2—3.5bar
- IMP-1 :Strong lime with 30’ baume Solid caustic + 28’ baume mercerize oil.
- IMP-2 :Here shrinkage is controlled by using caustic and mercerizing oil. Airing zone: In airing zone = 11 air roller/8 air rollerIn airing zone, fabrics are dried by air and chemical is added with fabrics.
- Gear+chain : Maintain width, control shrinkage in weft And caustic is utilized in every fibre equally.
- Tanki : No. of tanki-5These keeps water hot and creates weak line (8baume)
- Washing chamber (1-3): Hot wash 90’c
- Washing chamber 4: Wash at room temperature
- Cylinder dryer temperature : 110=-130’c
- Cooling dryer temperature : 25-40’c
- Exact roller : Maintain fabrics that, selvedge does not remain straight.Using acid according to fabric GLM -1. 300+GLM thick- 100% acid, 2. 140-274 thickness- 50% acid + 50% water
- Types of mercerizer : 1.cool mercerizer – 18’ baume . But for cool mercerizer good chellers are needed. 2. Hot mercerizer- 28-30’ baume
- Recipe: Sodium Hydroxide (NaOH) – (28±2)º Be (Baume´) 267 gm/l (see note) Steam, water – As required, Green acid / Nurta acid (32%) – 3-4 % of total water, Wetting agent- 1-1.5 gm/l,
- Compressed air -: As required
- Mercerizing Oil (Mercirol QW2F) : 3-4 gm/l
- Tests : Barium activity test, 2.PH, 3. Absorbency , 4. Size chemical Suitable For All cotton fabric, TC/CVC fabric, Twill Fabric
Flow chart of Mercerization
Washing Chamber 1 2 3
Operational Procedure for Mercerized Cotton Yarn:
Fabric inlet for mercerized cotton: Batcher from scouring & bleaching unit is feed into the inlet of mercerizing range. Where the fabric is passed over some free roller, guider & expander. Here there is a compensator to control fabric open width entry.
Chemical mixing tank for mercerized cotton: Caustic is mixed in a separate mixing tank. Here 30 BAUME concentration is ensured. It is ensured by mixing 300 kg caustic in 1000 liter water. BAUME can be adjusted by adding water or additional caustic. Then wetting agent & caustic is forced to main chemical mixing tank from which it goes to chemical tank to maintain uniform chemical height in the tank.
Impregnation-1(IMP) of Mercerizing Machine : Fabric comes to Impregnation-1 from inlet through guider & series of driven, free roller. In mercerizing process the only wetting agent & caustic is used. Temperature is around 60’C.
Airing zone of Mercerizing Machine : Fabric is passed over the Airing zone after chemical padding. Here there is no application of temperature & pressure. It involves 4 rollers which are driven by motor. This application is only for drying in contact of air which facilitates more chemical consumption from next bath
Impregnation-2(IMP): same as Impregnation-1(IMP). After that squeezing is occurred.
Gripping chain for mercerized cotton: from Impregnation-2 fabric pass over the free roller & comes in to chain for gripping. Here the fabric is stretched for control width. If crease mark is found from previous process, that can also be controlled by stretching. Here there is an additional option of showering by hot water. Which ensure proper cleaning & removal of residual caustic.
Stabilizing compartment : Below chain where hot wash occurred there is chamber for collecting caustic containing hot water. That is driven to caustic recovery plant for making it ready to mercerize chemical once again.
Washing chamber(1 2 3) for mercerized cotton: From chain by squeezing fabric comes directly to washing chamber. Here fabric passed over some driven roller to make proper hot wash. There are 3 hot wash chambers that are linked with one another & horizontally inclined. Here temperature is maintained is around 90’C.
Neutralizing chamber: after washing fabric goes through neutralizing chamber. Caustic make the fabric highly alkaline so that is neutralized by the addition of acetic acid. For controlling ph from control panel a command is given such as 7. Then the fabric will takes this amount of acetic acid which makes the fabric neutral by maintaining ph 7.
Dryer for mercerized cotton: After washing & neutralizing for drying process 2 stage vertical cylinder dryer is used. It is heated by steam. For course fabric the cylinder dryer temperature is around 180-200’c. and for pocketing fabric the cylinder dryer temperature is around 110-130’c.
Batching : Finally after drying the fabric is ready to dye. It is now rolled in the batcher for next process.
Barium Activities Test:
Barium activities test is done to know about the increasing % of absorbency of fabric & depth of luster. By barium activity we can also see that, after mercerizing remaining wax oil and other impurities are removed &strength is increased.
Blank Ba(OH)2 – A/M Ba(OH)2
Barium Activity%=————————————- x 100
Blank Ba(OH)2 – B/M Ba(OH)2
Process: The Barium activity test is done in two processes—
- Chemical test
- Application test
In this test only barium is used. So it is called barium activity test.
1) Chemical test:
Fabric = 5 gm
Soda ash = 2 gm/l
Detergent = 10 gm/l
Ba(OH)2 = 30 gm/l
Sample: a) One from before mercerization
- b) Other is mercerized fabric
- Taking 5gm fabric sample
- Adding 2gm soda ash & 10 gm/l detergent
- Then boiled for 1 hr
- After boiling, hot wash
- Then drying is done for 1min at 140°C
- 2gm fabric is cut from both sample (App. 1’’ square)
- Then the samples are dissolved in 30ml Ba(OH)2 solution (0.25 N)separately & kept for 2 hour.
- Then we will have to titration.
To do titration 0.1 N HCl is used.
For Blank Ba(OH)2 = 10ml (From 30ml)
For A/M Ba(OH)2 = 10ml (From 30ml)
For B/M Ba(OH)2 = 10ml (From 30ml)
Now from taking the reading of burette we get the barium activity % from the above equation.
21 – 17.8
B.A % = ————–X 100
21 – 18.6
- b) Application test:
Dye (Remasol deep black R.G.B) = 70 gm/l
Soda ash = 20 gm/l
Urea = 200 gm/l
Primasol – V = 10 gm/l
Primasol NP = 2 gm/
Remarks: In preparation section fabrics are prepared for dyeing by increasing whiteness, absorbency, removing impurities etc.
Dr. Joshep, DGM, Textile Division, Seotex Limited, USA