Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[1]

Acid Wash:

Acid wash is again becoming popular on denim jeans and we are going to see more of acid washes in

the coming seasons. Here, let’s have a quick look at the acid washing process. An acid wash finish

treatment creates significant contrasts in the color of the denim material. It can be done on Indigo &

Sulphur base fabric garments. As the randomly faded, acid washed style came into vogue in 1980s,

the process of treating denim in such a way began to become increasingly refined. Some tried to use a

method similar to the stonewashing, yet the fading did not occur as dramatically or throughout the

material. Acid-washed on apparel, (Phosphoric Acid is used in the process, acid would react with

fabric surface and destroy the fabric), is washed with thermocol ball, pumic stones or until it is

bleached almost white. During Acid wash, thermocol ball or pumic stones are used. By the action of

thermocol ball or pumic stones, irregular fading affect is developed on the heavy garments like

denims, thick canvas/twill, and sweater. The thermocol ball or pumic stones act a brushing action on

the garment fabric surface. It Super-size your silhouette in this slouchy denim jacket in vintage acid

wash.The area where more brushing action takes place there more dicolour or fadding affect is

developed and the area where less brushing action takes place less brushing action and takes place

less fadding affect will be developed. The multi-layer fabric areas like –collar, calf, pocket, placket,

side seam etc area will be brushed more than the single layer areas. As a result irregular fadding

affect will be developed on the garments fabric surface. Thus in this way fading affect may be

developed on the garment by acid wash technique. [1][6]

Acid washed pant

Objects of Acid Wash:

1. To produce irregular fading effects or old looking effect.

2. For soft feeling to wear the garments i.e. to improve softness.

3. To achieve the buyer washing standard.

4. To increase rubbing fastness.

5. To get vintage look (that must be something new look)

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[2]

Technique used in acid washing for washing:

This is the oldest of fashion washes in denim after stone wash. The name acid wash is in reference to

the acids used for this wash in old recipes. In new methods it is done with oxidation. Use of

bleach/oxidative is very safe and economical in comparison to acids. Different chemicals are

used and among them potassium permanganate (KMnO4) and sodium hypochlorite are

mainly used.

Acid wash is typically done by soaking pumic stone in hypochlorite. Sometime KMnO4 is used

in replace of bleach. Selection of oxidant is very important and mainly depends on the type of fabric.

When it is done with pumice stone the washer and garment should not contain any water. Dry

garment is much suitable for this process then a damp one. Pumic stones are soaked in bleach and left

it to open for little time so they get only damp rather than wet. Then they are processed in machine

with garments. The extent of effect is controlled with process time, concentration of oxidant solution

and quantitative ratio of garment to stone.

In some derivatives of this process cotton balls or cotton ribbons are used instead of pumic

stone. The impact of cotton is very different form pumic stone. It produces more merged and cloudy

effect. Cotton ball of cotton ribbon is more successful on damp rather dry garment. Again the

concentration of oxidative solution, time of process and quantity of  garments measures the effect.

Cotton towels are some time used for this effect to produce more cloudy patterns on garment.

Garment must be stone washed before going for acid wash. It is more prominent and uniform on

medium stone wash than dark or light washes. KMnO4 cannot be used with cotton balls/ribbons. It is

only possible with hypochlorite. Black sulfur is not process able with hypochlorite as sulfur reacts

vigorously with sulfur and pace of process cannot be controlled.

One important thing about acid wash is that the process is without water so the effect will

be more random and variation will to a larger extent than regular washes. So by keeping

the batch size minimum this variation can be controlled . The simple relation is larger is the

batch size greater is the variation in result [2]

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[3]

Technique Selection:

During machine rubbing garments and stones rotate and the stones drop on the garment surface. Due

to biting and brushing action of the stones, the garments become faded in spot pattern. By the action

chemicals present in the stone discolors the garments. The thick seam areas like collar, pocket, cuff,

side seam etc area are faded more than the remaining areas of the garments. During loading and

unloading of the garments in the washing machine, counting of be done to avoid double treatment of

a garment. If any garment is double treated, then the garment will be rejected. Before processing

second batch in the same machine, fresh soaked stones to be added in the washing machine.

Degree of fading: Due to biting and brushing action of the stones, the garments become

faded in spot pattern. The lot size of garments, machine drum diameter is considering

parameter. Stone quantity depends on that. Some time need deep fading that time machine

rpm is high time is high. Number of stone is higher when deep fading is needed. Soaking time

is very important to good oxidation. The ratio of soaking chemicals {potassium permanganate

(KMnO4): phosphoric acid (H3PO4)}[50:50].

Fabric type: Fabric type is very important in acid washing. All process ant technique time

temperature directly depends on fabric. For acid washing denim fabric is suitable. But all

fabric may allow is technique like, light garments like denims, thick canvas/twill, and sweater.

In Acid washing irregular fading effect is done by different fabric & fabric line. In a garment

has different seam line. When a garment bend or fold some portion has more contact with

other. In their surface contact is high so during washing friction is high so in a certain area

fading high. In a same batch body to body are different with other. It is impossible to match

body to body 100% precisely.[5]

Fabric GSM: After subsequent washing process the garments become

fully relaxed. This causes a decrease in GSM of fabric slightly. As the potassium

Permanganate is color discharging oxidant the acid wash caused a color fading of denim

garment with a frosty look due to irregular rubbing action of pumice stone. It was also evident

from the experiment that acid wash is less significant in the EPI & PPI of the denim apparel.

Due to washing the yarns become softer. As a result the count slightly increases both in the

warp and weft way. The area where more brushing action takes place there more discolor or

fading affect is developed and the area where less brushing action takes place less brushing

action and takes place less fading affect will be developed. The multi-layer fabric areas like –

collar, calf, pocket, placket, and side seam etc area will be brushed more than the single layer

areas. As a result irregular fading affect will be developed on the garments fabric surface.

Thus in this way fading affect may be developed on the garment by acid wash technique.[5]

Conventional Acid wash Technique:

In early 2000 some laundry tried doing the same wash soaking thermocol bolls in bleach or pp

solution to get this desired effect. While this process can be done using either light bleach, chlorine ,

potassium permanganate etc.

The most popular is PP Bleach and will produce the best acid washed results. Doing the process is

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[4]

very simple, but following all parameters in correct way to have right & repeatable results. The lot

size of garments, machine drum diameter, quantity of soaked stone / towels & skilled operator.

Initially, the Acid Wash process involved soaking pumice in Industrial Strength Chlorine.

However, it was discovered that potassium permanganate was more controllable and just as strong an

oxidizer. They simply marinated pumice stone in it and then vacuum packed the stone to the required

moisture level. Acid wash was a chemical process on denim that stripped the top layer of color off to

a white surface with the undertones of navy blue remaining in the jeans. [8]

The Materials

The process of acid washing jeans involves porous pumice stones or small towel pieces and chlorine

or Pp Bleach, such as you would put into a bucket or in drum for soaking process. Sodium-bisulfate

is used in the second washing for Neutralization. Also recommended is access to two separate

washing machines. One for Acid Washing & another one for further process i.e. Neutralization etc.

The Acid Washing Process on Denim Jeans

The process of acid washing jeans used chemicals, stripping off the color of the top layer, leaving the

white fabric exposed. The color remained in the lower layers of the material, giving it a faded look.

Acid washing could be done overall or made to look splotchy.

1).Soak porous pumice rocks or pieces of towels in chlorine or PP bleach solution for about 20

minutes to an hour. The longer you soak the pumice or towel, the more prominent the effects will be.

2).Once the stones are saturated with chlorine/pp, remove excess water from stones/towel then put

the stones in machine followed by the jeans in a washing machine for about 20 minutes. Make sure

machine do not have single drop of water, open the drain during complete process

3).At this time, check on the jeans to ensure they look acceptable, and then move them to another

washing machine for a regular washing process. Too long in the first machine can totally bleach or

ruin the jeans and too little time may not produce the desired results or can make patchy appearance.

Check on the jeans once every 10 minutes or so during the second wash process of neutralization to

ensure the desired look is achieved.

4).Next, fully dry the jeans in a dryer that gets nice and hot. [8]

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[5]

Latest acid washing process on Woven denim:

Denim apparels (jeans) were desized using detergent and desizing agent. The liquor ratio containing

Desizing agent Ne (2gm/l) and super-excel (1gm/l) and material to liquor ratio of 1:13. The process

was accomplished in an industrial horizontal sample washing machine (NgaiShing, Model-NS-2205,

Hong Kong) at 60°C for 20 min. Desizing treatment was carried out to remove the sizing material

from the yarn dyed denim. After that a hot wash was conducted at 70°C for 20 min following a cold

wash for 3 min.

Desized apparels were squeezed in Hydro-extractor m/c (Zanussi, Roaches International LTD,

England) at 200 RPM for 4 min to remove excess water from the apparels. Then the samples were

dried at 65°C for 25 min in a sample steam drier (OPTI-DRY, Roaches, International LTD, England)

following 5 min cold dry in the same machine.

The fresh pumice stones were soaked at room temperature for 10 min by shuffling using

Potassium permanganate (4gm/l, KMnO4) and phosphoric acid (1ml/ l, H3PO4) containing the liquor

ratio 1:2. Pumice stones are naturally perforated; hence pick up the solution very quickly

After the desired soaking of pumice stone, the completely dried desized apparels were treated with

them (damp pumice stone) at room temperature for 15 min at the same sample washing machine at 30

RPM without additional water followed by the standard washing procedure. After the treatment the

pumice stone were unloaded from the machine.

The acid washed apparels were conducted by a neutralization process, a detergent wash and a

softening process respectively. The neutralization process was carried out by sodium metabisulphite

(4gm/l) at room temperature for 5 min, detergent wash by super-excel (2gm/l) at 50°C for 10 min to

remove the breaking stone dust and adhering chemicals and Softening was carried out by Basu-soft

softener (1gm/l).

The acid washed apparels were squeezed and dried in the same hydro-extractor machine and drier

respectively following the same time, temperature and RPM. Then the treated apparels were assessed

to find out the changes of properties of denim apparel due to acid wash treatment. [5]

Pumice Stone:-

•The tone are the perforated stones, produced from volcanic explosion.

•At first these stones are soft but becomes cold, it becomes the stones with rough surface,

•Pumice stones float on water.

•Pumice stones come from Indonesia and Turkey.

•Indonesia stone color is slightly brown and Turkey stone is white color.

•Pumice stones are available in 3 size i.e. small 2-3 cm, medium 3-5 cm and large size 5-7 cm.

•Two to Three times can be used are pumice stone.

•Every bag contain 22 kg to 25 kg and price 400/= to 425/=/ bag (varies).

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[6]

Thermocol Ball

In early 2000 some laundry tried doing the same wash soaking thermocol bolls in bleach or pp

solution to get this desired effect. While this process can be done using light bleach, chlorine,

potassium permanganate etc.

Garments are washed with different kind of Balls like Emery, Rubber, Plastic and Silicone coated

Balls to give myriad finishes.

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[7]

Corksheet

Some times corksheet is used for abrasion .There are many size of corksheet used for acid washing.

All process is same only corksheet is used on the instead of thermocol/stone. Number of corksheet

pieces is depend on the load size of garments, machine drum diameter,

Stone/thermocol Ball

Stone/Cotton balls/Cotton ribbons are dipped in diluted solution of oxidant to make them ready for

process. It is very important to remove the excessive quantity of solution from stones. This will be

helpful in controlling the effects. This can be done by two ways. One is to let the soak out in open by

placing them on mesh sheet and them running them in washer without water. When they get semi

wet, they are ideal to use in process. This treatment is very useful for acid wash. Some time a

quantity of raw stones or cotton balls is added to treat ones to control the intensity of pattern. [2]

Apparatus:

Denim Jeans

Rubber Gloves

Laundry Bleach

Spray Bottle

Pumice Stones – like you use for a pedicure

Sodium bisulfate (optional)

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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1. Soak the pumice stones in the bleach overnight. The bleach will be absorbed into the stone.

Wear old clothes and rubber gloves while handling the bleach. Make sure you have a well-

ventilated area to work in.

2. Mix two parts bleach with one part water in a spray bottle. Randomly spray the pants

where you want the acid wash look to appear. Soaking the jeans completely will give you an

overall faded look while just working on certain areas will give you the splotchy look.

3. Take the bleach soaked pumice stone and scrub on the area of the jeans that you

choose. Try different effects. You may want to spray the jeans around the legs, but use the

pumice stones on the rear end of the jeans to give them a worn aged look. Get creative and

none of your acid wash jeans will look the same.

4. Allow the pants to sit for ten to fifteen minutes and watch the jeans begin to fade. The

longer you let them sit, the lighter they will get. However, it is very important not to leave the

bleach on for more then twenty minutes. The bleach will begin to eat away at the denim fabric

and ruin your jeans.

5. Set the washer for a small load and fill with water. Add a tablespoon of sodium bisulfate.

This will remove the extra bleach from the pants and allow you to wash them with other

clothes. If you do not have sodium bisulfate, wash your jeans several times by themselves or

only with other clothes you do not mind getting bleached.

6. Dry the acid wash jeans in the dryer as normal. If you want them to shrink, leave them in

the dryer until they are completely dry. If you do not want them to shrink, take them out while

they are slightly damp and hang them to dry the rest of the way.[7]

Acid Wash Process:

A processor Acid wash of 60 kg batch of Denim Trouser as mentioned below:-

Desizing

Stoning or/and Enzyming

Soap Rinsing

Acid Wash Process

Neutralization

Softener Application

Hydro Extractor Machine

Dryer Machine

Quality & Delivery

In acid washing basic chemicals

potassium permanganate (KMnO4)

phosphoric acid (H3PO4) or Ortho-phosphoric acid H3PO4,

thermocoal ball, pumic stones or corksheet

Sodium meta-bisulphite (Meta, Na2 S2O3),[5]

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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First Step: Pretreatment/Desizing.

1. Add water @ L: R = 1: 10.............. 600 litres.

2. Start Machine.

3. Add desizing agent @ 1 gm/litre .................600 Gms.

4. Add detergent @ 1 gm/litre ........................ 600 Gms.

5. Temperature............................. 60°c.

6. Time........................... 20 mts.

7. Drop the liquor.

8. Rinse one for 3 minutes (cold).

Second Step:Hot wash

1. Add water @ L: R = 1: 10.............. 600 litres.

2. Temperature............................. 60°c.

3. Time........................... 5 mts.

4. Drop the liquor.

5. Here hot wash is used to remove the adhering materials from the garment surface.

6. Unload the garments from the washing m/c in the trolley.

7. Load the pre treated garments in the dryer m/c.

8. Dry the garment completely & unload the garments.

9. The thermocal ball or pumic stones used for acid wash need to pre-treat in the following

chemical solution:

10. Water ..................... 100 L

11. Potassium per manganate.............. 1000 Gms.

12. Phosphoric Acid............................... 250 Gms.

13. Stire the solution in a stainless steel tub with dry pumic stone.

14. Soak the stones with the chemical solution ......... 10 –15 minutes.

15. The stones will pick up the solution. Then the soaked stones are dried in the open air

for.............. 2 to 3 hrs.

16. Then pre-treated garment 30 –40 kg per batch load in the dry washing machine.

17. Load the per-treated stones (about 50 kg) in washing machine.

18. Start machine running for each batch ........................ 7 to 10 mts.

19. Stop machine running.

20. Unload the treated garment separately. Pumic stones with P.P. solution hit on garment surface

as a result fadding will be developed.

21. Then load the stones treated garment in another washing machine.

Third Step:Wash for Cleaning

1. Batch wt................................ 70 kg.

2. Add water @ L: R = 1: 8.............. 560 litres.

3. Add detergent @ 1 gm/litre .............560 Gms.

4. Temperature............................. 40°c -50°c.

5. Time ..................................10 mts.

6. Drop the liquor.

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

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7. Here detergent is used to remove the breaking stone dust and chemicals from the garment

surface.

Fourth Step:Whitening/Neutralization

1. Add water @ L: R = 1: 8.............. 560 litres.

2. Machine running.

3. Add Metabisulphite @ 5 gm/litre..... 2800 Gms.

4. Cold temperature.

5. Time 5 mts.

6. Drop the liquor. [1]

Fifth Step: Soft Wash

1. Add water @ L: R = 1: 7.............. 490 litres.

2. Machine running.

3. Add Acetic acid @ 0.6 gm/litre ..................... 294 Gms.

4. Add Softner @ 1 gm/litre ........................ 490 Gms.

5. Then unload the garments.

Sixth Step:Hydro Extractor Machine

Hydro extractor machine to remove excess water from the garments.

Seventh Step:Dryer Machine.

After hydro extraction the garments are sent to drying m/c for complete drying.

Eighth Step:Quality & Delivery.

After drying the garments go to quality checking & rectify washing fault and then good one

delivery.

Effects of Acid wash on the properties of fabric

In Acid washing irregular fading effect is done by different fabric line. In a garment has

different seam line. When a garment bend or fold some portion has more contact with other. In their

surface contact is high so during washing friction is high so in a certain area fading high. In a same

batch body to body are different with other. It is impossible to match body to body 100% precisely.

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[11]

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[12]

Precaution:

Maintain the stock solution properly constant when comes socking the stone.

No water licks age in to the machine when treated pumic stone & garments in to the machine.

Not excess load the garments in the Acid wash processing.

Add some new stone after finishing on batch to maintain the volume for 2nd batch. It is a matter of

experience.

Color Shade Variation & Solution

When fabrics come in to garment factory against any order from abroad / local fabric dyeing factory,

its found different colour shade roll in the same colour i.e. slide light, slide dark, slide tone different

for this reason garment factory to control shade variation works as follows :-

8"×8" size fabric cut from every roll.

Marking roll number by permanent marking pen at back side of cutpes.

Every cutpes joint each other and make a blanket.

Then it washes into standard approval shade.

Garment factory now segregate same colour tone in one bundle and shade grading A.B.C.D.

First A shade roll cutting by pattern then B.C.D shade separately.

After garment making shade level attached on body.

Then go to washing plant for standard washing.

Washing plant shade level wise washing in respective wash.

After wash it any big shade variation found then again rewash to match with buyer approval standard.

Final quality checking garment go to finishing section for thread cutting, button attached, iron &poly

etc.[1][3]

Apparel wash & Finishing Azmir Latif (MSc. in Textile Engineering)

[13]

Conclusion In a garment has different seam line. When a garment bend or fold some portion has more contact

with other. During machine rubbing garments and stones rotate and the stones drop on the garment

surface. Due to biting and brushing action of the stones, the garments become faded in spot pattern.

By the action chemicals present in the stone discolors the garments. The thick seam areas like collar,

pocket, cuff, side seam etc area are faded more than the remaining areas of the garments. During

loading and unloading of the garments in the washing machine, counting of be done to avoid double

treatment of a garment. If any garment is double treated, then the garment will be rejected. Acid wash

is a cool and pretty way of making a fabric different from average jeans. It was started in the mid-'80s

by the Italian company Rifle Jeans, and it has grown in popularity over time. It remains an active

style for jean designers [4]. Garments made from denim and heavy jeans fabric are normally

considered for acid wash.[6] The implication of acid wash on the properties of denim apparel also

inspected. Properties were influenced by the chemical action combined with rubbing action of the

pumice stone and accelerated with the action of rotating cylinder of washing machine. It has been

investigated from different study that stiffness, GSM, fabric weight, breaking strength is reduced due

to acid wash whereas EPI, PPI and count slightly increased. It has been further noted that acid wash

gives a frosty or freezing look on denim apparel. It is concluded that this technology can be applied in

the sample washing of woven denim apparel as a time saving method. [5]

Reference:

1. http://textilelearner.blogspot.com/2012/07/acid-wash-objects-of-acid-wash-

process.html#ixzz3R4qhPE5o

2. http://www.denimhelp.com/denim-garment-process-acid-wash/

3. Industrial Garments Washing & Dyeing By Engineer Md. Golam Faruk (Ovi)

4. http://www.ehow.com/how_2302354_acid-wash-clothes.html

5. International journal of technology of acid wash on woven denim apparel

With damp pumice stone by Upama Nasrin Haq and Md. Mashiur Rahman Khan

6. Practice of garment merchandizing & management by Md.Faruk Hosen

7. http://www.mademan.com/mm/how-make-acid-wash-jeans.html#ixzz3R4fJDYc3,

http://www.mademan.com/mm/how-make-acid-wash-jeans.html#ixzz3R4fOUvPY

8. http://3bp blogspot.com/_mxs1wmxSW34/SISaNmqKmAI/