Latest Dry Washing Techniques in Denim Garments

Last Updated on 09/01/2021

Latest Dry Washing Techniques in Denim Garments

Authors: Asma Akhi &
Md.Hasibur Rahman Sunny

Dept. of Textile Engineering
Bangladesh University of Business & Technology

 

Introduction
Denim garment (Jeans) washing or denim washing is one of the most widely used finishing treatments that have vast usage, due to its effects on appearance and comfort. Without washing, the denim garment is uncomfortable to wear, due to its weaving and dyeing effects. It essentially needs a finishing treatment to make it softer, more supple and smooth which enhance wearer’s comfort.

Fashion is today incomplete without denim. Denim comes in all forms, looks and washes to match with every dress. Dry washing process which is most popular for denim garments.

Bangladesh is a textile-based country, Denim apparel are being produced with other apparel to meet demand in the competitive market of the world. Today’s are very fashion concern; it is very challenging to meet their quick change of current demands. At present the demand of denim apparel with faded look so increasing rapidly. Various types of washing have been used on denim apparel to give them used look. Common washing practices are Bleach wash, Enzyme wash, Garments/Normal wash, Bleach with Stone wash, Acid wash, Pigment wash etc. Among methods the Bleach wash & Enzyme wash is very widely used in the washing industry. Also used various types of dry washing like Hand brush, Grinding, Destroy, Whiskering, PP spray, Tagging, 3D etc in denim garments.

The distressed jeans or denim that we see around everywhere undergo a wide variety of wet as well as dry washing treatments to get the desired effects. Destroying denims is as much an art as it is a technique. The direction in fashion is varied across all areas particularly in denim dry washing process, whether worn or torn to wrinkled or pressed; these trends can appeal to a wide range of consumers. These can be achieved by variety of denim dry washing techniques which are mainly dependent on physical and on chemical abrasion of the surface dye there by producing different wash-down looks to the denim fabrics.

In a twill weave (used in denim), the fabric is constructed by interlacing warp and filling yarns in a progressive alternation which creates a diagonal effect on the face, or right side, of the fabric and has a surface of diagonal parallel ridges. In some twill weave fabrics, the diagonal effect may also be seen clearly on the back side of the fabric. Due to the denim’s right-hand twill construction, one color predominates on the fabric surface, Most of the Denim fabric construction is either 2/1 or 3/1 construction of either left or right-handed twill. Also because of this way of weaving the threads to make the fabric, the fabric is very strong and durable.

Over the years, many different denim fabric treatments have been introduced, including pre-washed, stone-washed, sand blasting, and dirty.

Purposes of Garments Washing:

  1. Washing process of garment is done to create wash look appearance. After washing the garments create a new look which seems the new touch of fashion.
  2. By the washing technique, faded/old look, color or tinted affect is created in the garments which also seem the best touch of garments.
  3. It also produces different outlook.
  4. Washing technique creates new fashion such as tagging, grinding, destroy, whiskering, permanent wrinkle, P.P spray, hand crapping, 3D etc. Which also seems the best touch of garments.
  5. The main and important function of washing is to reduce size materials as a result the garment become size free and become soft hand feel.
  6. When these soft garments are touched then it seems to best touch of garments.
  7. To attraction the customers/Buyer by different types of Fashionable washing and market developments.

CHAPTER-02
Literature Review

Hand Scraping/Hand Brush:
Sand ballasting with emery paper, commonly known as scrapping is the most widely used process for creating the blasting effect. It is usually done by mounting the garment on rubber balloons/dummy. After mounting the garment air balloon is filled with air to expose the area to operate. It is important to fill the pressure. Hand sand is the step which is generally being done in rigid form of garments to get the distressed look. Locations can be front thigh & back seat or it can be overall/global application as per the Standard.

Destroy:
One of the most popular distressing effects currently, ‘Destruction’ is an art which make denim look unique & used. To make destruction pen type of stone tools being used in mid of wash process to apply on desired area. It can also be achieved by cutting it thru knife the warp yarns & keep the weft yarn as is to show white thread. Holes also can be made by cutting weft & warp yarns. These are all manual processes & every garment will look unique & different than others.

Tagging:
In this process the effect is created by swift tag machines with the help of plastic or nylon tag pins in rigid form of garment to get contrast. Usually tag pin machines are used to attach tag pins to garment. The procedure is very simple and proceeds as; garment is folded on required area and tacked through folds.

Whiskering:
Whiskers are one of the most important designs of a used look garment. The idea of whiskers is taken from the worn-out lines and impression patterns generated by natural wearing on hips and front thigh area. It is also known as Cat’s Whisker.

Potassium Permanganate Spray (P.P Spray):
Potassium permanganate spray is done on jeans to take a bright effect on sand blast area. One important thing about potassium permanganate spray is, this is usually a sporting process to increase the effect of sand blast. Potassium permanganate solution is sprayed on blasted area of jeans garment with the help of normal spray gun. This potassium permanganate spray appears pink on garment when fresh and turns to muddy brown on drying. The garment is hanged in open to dry after potassium permanganate spray and when the potassium permanganate turns its colors completely then it is considered to ready for next process. It is always followed by neutralization process. Sodium Meta bisulphate is most commonly used neutralizer.

Crinkle/3D:
A crinkle is a fold, ridge or crease in the cloth or garments. Wrinkle is a particular type of pressure in the finished fabric. It is produced during finishing operations by the thickness of the seam used to join pieces for processing. Wrinkle resistance in a fabric is a desirable attribute, but it is not easily measured quantitatively. Wrinkle resistance varies from quite low in many fabrics to very high in resilient fabrics. In order to form a wrinkle, a fabric’s wrinkle resistance must be overcome. The fabric may, however, produce strains and store potential energy that can become evident as wrinkle recovery under suitable conditions. First have to do spray resin on the specific area we want to create 3D effect. Without resin spray 3D effect is not possible.

Denim:
Denim is a twill-weave woven & 100% cotton fabric that uses different colors for the warp and weft. One color is predominant on the fabric surface. Denim wears well and resists snags and tears. It is available in different weights and is usually made of cotton, although hemp denim is also available. Denim is commonly used for jeans and work clothes, as well as for casings for organic futons and pillows. In today’s trend Denim has achieved much preference to teenagers as well as baby to adult as blue jeans. According to the fashionable denim garments, subjected to versatile washing techniques to obtain a worn, vintage look with various effects like as hand sand, whiskers, 3D, Destroy etc. To produce a fading effect is the main object of denim washing without affecting the main body fabrics and patchiness, crinkles, seam puckering, hairiness, de-pilling, softened-hand feel, stabilized dimensions etc.

Denim Fabric
Fig 01: Denim Fabric

History of Denim:
Jeans are pants made from denim or dungaree cloth. They were invented by Jacob Davis and Levi Strauss in 1873 and a worn still but in different context. Jeans are named after the city of Genoa in Italy, a place where cotton corduroy, called either jean or jeans, was manufactured. Levi Strauss came from Germany to New York in 1851 to join his older brother who had a dry goods store.

In 1853 he heard about Gold Rush in the West so moved to San Francisco to establish Western Branch of the family dry goods business.

There he sold, among other things, cotton cloth. One of his costumers was Jacob W. Davis, tailor from Reno, Nevada. Davis made functional items such as tents, horse blankets and wagon covers.

One day, his costumer ordered a pair of strong pants that could withstand hard work. He made them from denim that he bought from Levi Strauss & co and made them stronger by placing copper rivets at the place’s pants rip the most: pockets and flies. When he wanted to patent them, he wrote to Levi Strauss and they became partners. They opened bigger factory and that is how jeans were born.

Characteristics of Denim Fabric:

  1. Warp yarns are colored (usually with indigo, vat, blue or sulphur black).
  2. Structure: right hand or left-hand twill, i.e. z/s-twill of 2/1 or 3/1 construction.
  3. Usually made of cotton yarns of coarser count (7s, 10s, 14s, 16s, etc.).
  4. Coarser cloth (weight lies between 6-14 oz/sq. yds) and used for pant and warm jackets.
  5. It is for long wearing.
  6. It is very strong and durable.

Weave Design of Denim:

  1. We all know that the denim fabric is constructed with twill design, Now let us take a brief look about twill construction.
  2. A distinct design for the twill weave is it forms a diagonal line.
  3. In the right hand-twill, the diagonals run towards to the right.
  4. In the left hand-twill, the lines run towards to the left.
  5. The simplest twill weave is either 1/2 or 2/1 twill (Three Leaf Twill).
  6. 3/1 or 1/3 is called Four Leaf Twill.

Classification of Denim:
The weight per/unit area of denim is,

  1. Light Weight: 4.5 to 7 oz/sq. yd
  2. Medium Weight: 7 to 10 oz/sq. yd
  3. Heavy Weight: 11 above

The Hue/Tone & color of denim is,

  1. Indigo Vat
  2. Sulphur black

The fabric structure/design of denim is,

  1. Plain
  2. Twill (S-twill, Z-twill, Herringbone & Zigzag twill)

You may also like: Process Flow Chart of Denim Manufacturing

Denim washing:
Denim washing is done to produce effects like color fading with or without patchiness, crinkles, seam puckering, hairiness, De-piling, softened-hand feel, stabilized dimensions etc.

Types of Denim Wash:
Denim washes are two types:

a. Mechanical washes

  1. Stone wash
  2. Micro-sanding

b. Chemical washes

  1. Denim bleaching
  2. Enzyme wash
  3. Acid wash
Wash Type of Denim
Fig 02: Wash Type of Denim

Types of Garments Wash: 

Types of Garments Wash

  1. Normal wash/ garments wash/ rinse wash
  2. Hand Brush/Hand Scraping
  3. Pigment wash
  4. Whiskering
  5. Caustic wash
  6. PP Spray/PP Sponge
  7. Silicon wash
  8. Destroy
  9. Stonewash
  10. Crinkle
  11. Enzyme wash
  12. 3D
  13. Stone Enzyme wash
  14. Tagging
  15. Acid wash
  16. Sand Blasting
  17. Bleach wash
  18. Tinting wash Overall Whiskering

Dry Process:
Hand Scraping/Hand Brush:

  • Garments are wearing on a dummy or pattern board.
  • Hand scraping is done on specific area of garments by emery paper according to approve sample.
  • Different type of emery paper is used like 220, 320,400,600.
  • Most common used grade no of emery paper is 320.
  • Then sent for further processing.

Destroy:

  • This process is done manually by destroy machine.
  • Glass pencil/blade is used in this process.
  • Destroy is done on specific area of garments.
  • Destroying warp yarn by blade gives new outlook.
  • Garments sent for further processing.

Tagging:

  • Tagging is done on garments for fashion and value-added fashion wear.
  • In this process tag pin is used.
  • At first garments are clipped with tag pin by tagging machine.
  • After wash upper portion of garment occurs crease marks & inside of tagging occurs dark shade.

Whiskering:

  • At first design is produced on pattern board according to buyer requirement.
  • Then pattern board is placed inside the garments.
  • Then hand rubbing is done by emery paper on Specific area.
  • By using different types of emery paper (220,320,400,600) design is produced on surface of garments.
  • Most common used grade no emery paper is 320.
  • Then sent for further processing.

Potassium Permanganate (P.P) Spray:

  • At first a solution is made by potassium permanganate & water.
  • Sometimes CH3COOH (acetic acid) is used for solution preparation.
  • A spray gun machine is used for spraying the P.P solution.
  • Spray gun m/c spray the solution as per requirement.
  • A few minutes later reddish color is found on the surface of garments.
  • Then garments sent for further processing.

Crinkle:
Permanent crinkle given on denim surface are known as crinkle effect. Resin application is done on denim to retain crinkle by using iron machine or pressing crinkle machine and even after wash.

3D:
First have to do spray resin on the specific area we want to create 3D effect. Without resin spray 3D effect is not possible. A garment is in metal plate. Crease is made in required place. Then two times pressing is done. The temperature is 1900c. Light temp is 1000 watt, it deep the resin and then it send to the curing to make wrinkle. Then it set to the dummy and makes 3D effect by the help of hand of workers manually.

Wet Process:

Desizing Wash:

  • This is very first & basic step but most important step of washing.
  • This process removes impurities, starch & stains during handling of fabric.
  • Methods of Removing Sizes from Denim Jeans
  • Washing with High Alkaline agents (i.e. Soda ash)
  • Washing with High Acidic agents (i.e. Acetic acid)
  • Washing with Oxidative chemicals (i.e. Hydrogen Peroxide)

Enzyme wash:
To remove the size materials from the garment’s enzyme wash is applied. Enzyme wash is done on garments made from denim & jeans fabric, twill fabric garments. Sometimes knit items are also subjected for Enzyme wash. Garments made from indigo, vat, direct etc. dyed fabric can be enzyme washed. Enzyme works chemically not mechanically for this reason it provides less damage/wastage then stone wash. It improves improve the color fastness & rubbing fastness. Enzyme improves the anti-pilling properties and decrease the hairiness hence it gives a very smooth surface of the garments.

Bleach wash:
Garments made from indigo, vat, reactive, direct etc. dyed fabric can be bleach washed. It is a discoloration process by oxidation action. Color can be removed uniformly from the garment and removal of color done as per requirement. In general, there are three categories such as light bleach (where maximum color is removed), medium bleach and bleach. All types of garment can be washed. Such as: woven knit garments. In case of woven fabric, a pretreatment (Desizing) process is required. Dust, dirt, oil spot, impurities etc. are removed that may come from during process i.e. cut- ting, stitching and the back process.

  • Calcium hypo chlorite
  • Sodium hypo chlorite
  • Hydrogen peroxide
  • Potassium permanganate

Effect of Denim after Dry Process:

Hand Scraping/Hand Brush:
Scraping can be done on inflated rubber balloons for better effect (horizontal or vertical it’s up to operator’s convenience), even it can do plain wooden board of garment size & hand pressure should be uniform in order to get better results.

Destroy:
One of the most popular distressing effects currently, ‘Destruction’ is an art which make denim look unique & used.

Tagging:
This effect can be designed anywhere on the garment in different styles. Most favorite areas for tacking are on waistband, bottom hems, back pocket and front pocket corners etc. On front or back sides of garment, tacking can also design horizontal of vertical patterns on full length panel.

Whiskering:
Whiskers are one of the most important design of a used look garment. The idea of whiskers is taken from the worn-out lines and impression patterns generated by natural wearing on hips and front thigh area.

Potassium Permanganate Spray:
PP Spray is being done on denim garments to achieve local abraded area to appear whiter than back ground indigo color shade.

Crinkle/3D:
Permanent wrinkles given on denim surface are known as crinkle effect. Resin application is done on denim to retain crinkle.

First have to do spray resin on the specific area we want to create 3D effect. Without resin spray 3D effect is not possible.

Function of Chemicals Used in Washing:

Desizing:

It is used to remove mainly starches, waxes, fats, pectin’s, minerals & Indigo dye from denim, twills, poplin &canvass fabrics etc.

Enzyme:

  • The action of enzyme during enzyme wash it hydrolysis the cellulose.
  • At first it attacks the having projecting fibers & hydrolyzed them.
  • Then it attacks the yarn portion & partly hydrolyzed them.
  • As a result, color comes out from yarn portion & faded effect is produced.
  • Sodium Meta Bi-Sulphite (Na2S2O5):
  • It is used for neutralizing the activity of KMnO4 on fabric/solute.

Bleaching Powder (CaOCl2):

  • Bleaching agent is an oxidizing agent.
  • It is used for color out from denim garments.
  • We can achieve different shade (dark, medium, light) from garments by this agent.

Soda Ash (Na2CO3):

  • Soda ash create alkaline medium in wash bath.
  • It helps to uniform bleaching action in bleach bath.
  • It has cleaning power &help color fading effect of garments.
  • It is used for color fixing in dye bath.
  • It is also used for maintaining pH of wash bath.

Potassium Permanganate (KMnO4):

  • It is used for discolorations of fabric.

Softener (Cationic, nonionic):

  • It is used to make the garments soft.
  • It also provides excellent lubricating properties.

Sodium Chloride (NaCl):

  • It helps to exhaust dye in to the fiber.

Hydrogen Per Oxide (H2O₂):

  • H2O₂ creates the prime role in bleach wash technique.
  • In alkaline medium H2O2 breaks up and gives some perhydroxhyle ion.
  • Hydrogen per oxide is used in scouring, bleaching bath to occur bleaching action for white/ready for dyeing of gray fabric garments.
  • It is also used for neutralizing the garments from alkaline condition.

Resin:

  • Resin is used for semi-permanent creases in denim.

Binder:

  • Binder is a film former consisting various polymer.
  • Polymer contains reactive group & it forms crosslink during curing.

Acetic Acid (CH3COOH):

  • To neutralize the alkaline condition of garment.
  • To control pH value in wash bath.

 CHAPTER-03
Raw Materials & Methodology

The methodology of this project work was experimental. To perform a successfully experiment, the following materials, chemical, instrument and methods were used in our project work.

Material:

  • Denim Fabric (70% Cotton 20% Poly 10% Rayon)
  • Emery Paper (320)

Chemical:

  • Potassium Permanganate (KMnO4)
  • Resin
  • Neutral Agent (Meta BSF)
  • Desizing Agent
  • Enzyme Agent
  • Sodium Carbonate/Soda Ash
  • Bleaching Powder
  • Softener

Working Place:

  • Paradise Washing Plant Ltd.
  • Testing laboratory in Bangladesh University of Business & Technology
  • Wet Processing Laboratory in Bangladesh University of Business and Technology (BUBT)

Types of Machineries Used for Dry & Wet Process/Washing:

  • Destroy Machine
  • Pressing Crinkle Machine
  • Iron Machine (For Crinkle)
  • Tagging Machine
  • Spray Gan Machine (For PP Spray)
  • Sample Washing Machine
  • Hydro-extractor
  • Dryer Machine

Chemical, Material, Instrument & Method:

For Hand Scraping/Hand Brush:

Material: Emery paper

Instrument: Rubber Balloon/Dummy etc.

Method:
Hand brush with paper, commonly known as scrapping is the most widely used process for creating the blasting effect. It is usually done by mounting the garment on rubber balloons. After mounting the garment air balloon is filled with air to expose the area to operate. It is important to fill the pressure.

Hand sand is the step which is generally being done in rigid form of garments to get the distressed look. Locations can be front thigh & back seat or it can be overall / global application as per the Standard. Emery paper is being used to scrape the garments in particular placement & design. Emery paper comes in different number generally start from 40 till 600 and above, higher the number finer the emery paper, lower the coarseness of the paper. In the garment industry from 220, 320 & 400 number papers are most popular & widely used. Purpose of doing this process is make used worn out look to the garments.

Most common used grade no of emery paper is 320.Then sent for further processing. Hand rubbing is done on specific area of garments by emery paper according to approve sample. One garment must be done by one operator only to have balance intensity on both the leg.

Hand Brush Sample
Fig 03: Hand Brush Sample

For Destroy:
Material: Emery Paper, Stone Tools

Instrument: Destroy Machine, Hacksaw Blade, Knife, Needle etc.

Method:
Destroy is newly fashion on garments. One of the most popular distressing effects currently, ‘Destruction’ is an art which make denim look unique & used. It can also be achieved by cutting it thru knife the warp yarns & keep the weft yarn as is to show white thread. Holes also can be made by cutting weft & warp yarns. These are all manual processes & every garment will look unique & different than others.

  • We can make holes in jeans by overdoing different methods. The trick is to make the holes look natural. Grind away at the fabric slowly. Try not to localize the worn area, spread it with diminishing wear the further we get from the intended hole.
  • The area around the hole should be worn out as well as bleached to further blend the hole with the surrounding fabric. “Finish” the edges with a pumice stone or sandpaper dampened in bleach. Also dampening a sponge with bleach and applying it to the outer edges of the hole will add to the natural worn look.
  • It is important that what types of look we want to see on our denim. It is recommended using a sharp pocket knife/blade. Be careful, they are very sharp. Rub the blade of the knife/blade perpendicular to the line of the rip that we want.
  • To reinforce this newly created hole, turn your pants inside out and place an adequately cut piece of fabric around it and sew it. An iron on will work as well, but the stitching, done either by hand or with a sewing machine, will make it look much better.
  • It is preferred that not too many holes, 3 to 5 should be enough. The current trend, however, seems to be for smaller holes.
Destroy Machine
Fig 04: Destroy Machine
Destroying sample By Machine
Fig 05: Destroying sample By Machine
Destroying sample By Knife
Fig 06: Destroying sample By Knife

For Tagging:

Material: Plastic or Nylon Tag Pins

Instrument: Tagging Machine

Method:
Tacking or more commonly tag pinning is a very in fashion style in denim garment in these days. In this process the effect is created by swift tag machines with the help of plastic or nylon tag pins in rigid form of garment to get contrast.

Usually tag pin machines are used to attach tag pins to garment. The procedure is very simple and proceeds as; garment is folded on required area and tacked through folds. Number of folds can be two to four or five in regular in tacking. These tag guns are not especially designed for heavy folds like we do in tacking so durability of the gun is a consistent problem. Also broken needles of tag gun are issue for both operator and consumer. Automated tacking machines are used more successfully in some units. These machines are bit expensive but are far more efficient and secure than tag guns.

Tagging Sample
Fig 07: Tagging Sample

For Whiskering:

Material: Sand Paper

Instrument: Cutter Knife, Pattern Board, Rubber balloon etc.

Method:
Various methods are designed to create this impression on jeans. Such as: –

Mostly rubber balloons are available with different pattern designs. Garments are mounted on balloons and filled with air to get impressions of whiskers. Garment is scrubbed over pattern carefully with sand paper on engraved pattern lines. This operation requires high skilled labor and who can handle uniformity and sequence in whisker line. Fabric may damage during rubbing if care is not taken. This method is famous for high quality and cost effectiveness.

Sometimes separate patterns are made and fixed on balloons to make mustaches. These patterns are made of thin rubber sheets and electric wires or rubber cords and pasted on balloons for pattern lines. Thin line patterns are very easy to work in that way but it is not much successful for broad lines.

Engraved patterns on thick board like hard rubber sheets are widely used for whiskers impression making. This idea is very simple to draw lines on rubber sheets and engrave them with blade. Garment is places on sheet and scrapped on specific area to draw this impression on garment. For its low-cost patterns, it is most frequently used in small industries especially where the production is not consistent to style.

Whiskering pattern made followed by a Style
Fig 08: Whiskering pattern made followed by a Style
Making whiskering effect on the body
Fig 09: Making whiskering effect on the body
Whiskering Sample
Fig 10: Whiskering Sample

For Potassium Permanganate Spray (P.P) Spray:

Chemical: KMnO4

Material: Emery Paper

Instrument: P.P Spray Gun, Rubber Balloon etc

Method:
Potassium permanganate spray is done on jeans to take a bright effect on sand blast area. One important thing about the potassium permanganate (KMnO4) spray is, this is usually a sporting process to increase the effect of sand blast. Potassium permanganate solution is sprayed on the blasted area of jeans garment with the help of a normal spray gun & this solution is made by potassium permanganate & water, Sometimes CH3COOH (Acetic Acid) is used for solution preparation. Garments are mounted on balloons and filled with air to get impressions of PP spray. Garment is scrubbed over pattern carefully. This operation requires high skilled labor and who can handle uniformity.

This potassium permanganate spray appears pink on the garment when fresh and turns to muddy brown on drying. The garment is hanged in open to dry after potassium permanganate spray and when the potassium permanganate turns its colors completely then it is considered to ready for the next process. Doing after enzyme or bleach cycle will give more natural & white effect that doing in rigid.

It is always followed by neutralization process. Sodium Meta bi-sulphate is most commonly used neutralizer. A number of products are available in the market for the neutralization process like sodium meta bi-sulphate selected on the bases of effect required on blasted area.

Raw Sample
Fig: 11: Raw Sample                    Fig: 12: PP sample

For Crinkle/3D:

Chemical: Resin (Catalyst, Silicone & PU solution)

Instrument: Pressing Crinkle Machine, Iron Machine, Dryer etc

Method:
First have to do spray resin on the specific area we want to create 3D effect. Without resin spray 3D effect is not possible. A garment is in metal plate. Resin (Formaldehyde free) being used for achieving 3D effect (3 Dimensional), Rigid Look etc. This process can be done by spraying or dipping the garments in to Resin, Catalyst, Silicone & PU solution in right combination according to the fabric strength & desired effect needed.

After application of resin solution in right proportion, make manual designing as needed on the thigh, hip & back knee area to get 3Dimentional effect. After making it, it should be manually dried with hot press or hair dryer & The temperature is 1900c, it deep the resin and then it sends to the curing to make crinkle. Then must be cured in oven at right temperature, time as mentioned in resin product manual.

If resin not cured properly, 3D effect will not be permanent & can cause skin irritation to the wearer. Highly skilled operators need to execute this process in order to get consistency & uniformity.

Crinkle Sample
Fig 13: 3D Sample …………………………..Fig 14: Crinkle Sample

Washing Condition:

No. of Sample 07
M: L 1:80
Temperature 450c,600c,700c
Time 114 min (All Wet Process)

Working Recipe:

Neutral Wash:

  • Water: 80L
  • Neutral Agent (Meta Bi Sulphite): 400gm
  • Time: 11min
  • Temp: 450c
  • Rinse: 2min

Desizing Wash:

  • Water: 70L
  • Desizing Agent :100gm
  • Time :10min
  • Temp :600c
  • Rinse :4min

Enzyme Wash:

  • Water :60L
  • Enzyme Agent :200gm
  • Time :35min
  • Temp :450c
  • Rinse: 4min

Bleach Wash:

  • Water: 60L
  • Bleaching Agent: 400gm
  • Time: 25min
  • Temp: 600c & 700c
  • Rinse: 2min

Softening Recipe:

  • Water: 60L
  • Softening Agent: 200gm
  • Time: 5min
  • Temp: 35 0c
  • Hydro-extracting & Drying: 5min & 700C

Working Process:

Start the sample dying machine

Run the m/c for 2 min at temp 37⁰c with required water

Drop the liquor

Load the sample with water 80L

Added Neutral agent (200gm)

Rise the temperature 45⁰c & Run the m/c for 11min

Drop the liquor

Again loading the water & Rinse wash for 2min

Drop the liquor

Machine loaded with water 70L

Added Desizing agent 100gm

Raise the temperature 60⁰c & Run the m/c for 10 min

Drop the liquor

Again m/c loaded with water

Continue washing 2min

Drop the liquor

Again m/c loaded with water

Then Rinse washing 2min at temp 400c

Drop the liquor

Load the sample with water 60L

Add Enzyme agent (Lanzene TA super) (200gm)

Raise the temp up to 450c for 35min

Drop the liquor

Again machine loaded with water

Then Rinse wash for 4min at 40⁰c

Drop the liquor

Load the sample with water 60L & added Cl Bleach 100gm

Raise the temp up to 600c for 5min

Then again added (100gm+100 gm) =200 gm Cl Bleach

Run the m/c for (5+3) = 8 min at 60⁰c

Then again added 100gm Cl Bleach

Run the m/c for (5+3+4) =12 min at 70⁰c

Drop the liquor

Again m/c loaded with water & rinse wash for 2min at 35⁰c

Unload the m/c

Machine loaded with water 60L

Added Neutral agent (Meta BSF) 200gm

Run the m/c for 6 min at 45⁰c

Drop the liquor

M/c loaded with water

Raise the temperature 45⁰c for 2 min

Drop the liquor

Again m/c loaded with water 60 L

Added 5% Softener 200gm (Pill soft)

Run the m/c for 5 min at 35⁰c

Drop the liquor

Unload the sample

Hydro extractor the sample for 7 min

Unload the sample

Dry the sample for 15 min

Unload the sample

Storage

Types of Instrument Used for Testing:

Testing Instrument Used For
Tear Strength Machine Tear Strength Measurement
GSM Cutter GSM Measurement
Counting Glass & Magnifying Glass EPI & PPI
Bessley’s Balance Count Measurement

Testing & Procedure:
Following test are done:

  1. GSM Test
  2. Tear Strength
  3. Count Measurement
  4. EPI & PPI Test

1. GSM Test:
The GSM of fabric is one kind of specification of fabric which is very important for a textile engineer for understanding and production of fabric. ‘GSM’ means ‘Gram per square meter’ that is the weight of fabric in gram per one square meter. By this we can compare the fabrics in unit area which is heavier and which is lighter.

Apparatus:

  • GSM cutter
  • Electric balance

Machine specification: Specification of a GSM Round cutter:

  • Area of Specimen: 100 cm²
  • Diameter. Of Specimen: 113 mm.
  • Type of Cut: Standard
  • Blades: Heavy duty Reversible Blades
  • Fine Brass safety Lock
  • Hand Wheel (Handle): Special Bakelite Handle
  • For repetitive test without fail the cutting pad should be new rubber-foam pad.

Working Procedure of Measuring GSM of a Fabric:

  • For Measuring GSM, fabric sample is cut by GSM cutter
  • Now weight is taken by electric balance.
  • By this way we get the weight in gram per one square meter fabric.
  • Here GSM of the fabrics by the GSM cutter is obtained by the multiplying the sample weight with 100.

GSM:
Sample Weight (gm) x 100 = GSM
Sample Weight = 4.4
GSM = 4.4 x 100
= 440 gm

GSM Cutter
Fig 15: GSM Cutter

2. Tear Strength Test:
The Tear Strength of fabric is a test that provides a measure of resistance to tearing. Tear strength may also be used to illustrate the anisotropy of a material. Force required to propagate an existing tear is measured. As a part of the preparation of fabric specimen, a cut is in them and the force is required to extend the cut is measured. A number of tear strength test is carried out and the average is taken to determine the tear strength. Tearing strength is expressed either in pounds or grams.

Purpose:
To demonstrate the proper way of the garment/fabric before and after processing to ensure the proper physical strength.

Method:

  • Tearing strength can be measured by using tearing tester. The specific sample is prepared with an initial cut which is 2.95-inch length and 3.93-inch width, and the instrument continues the tear until it reaches the other edge of the specimen.
  • The tearing tester consist of pendulum with a clamp mounted on it. The other clamp is fixed to the frame. At the start of the test, with the machine in a raised position, the two clamps are aligned when they are released, one clamps moves away from another one and the specimen tears. The result shown by a pointer on a scale can be expressed as the force necessary to continue the tears or as the work done.
  • Rotate the fabric clock wise 900 and repeat step 4-9 for warp thread direction insuring to mark the rawings with fill for the tear marker.
  • Put a small cut in the bottom of the specimen using the blade label under the clamp on the tester.
  • Ensure that the tester is set to 0 and release the pendulum. Allow it to freely swing to the right and with your left hand catch the pendulum as its swings back to its original position.
  • Note the result of the test and record the test result in pounds on the warp and repair the same steps for the Fill Tear Testing specimen.

Calculation:
Calculation of Tear strength in Pounds ꞊ (load carried out by the machine × point of indication)/100

Example: The pointer is showing the value 65% i.e. The value of tearing force is 65% of the applied force (considering the applied load is 6400g) Means the tearing force is

꞊ 65% of 6400g
꞊ 65/100×6400g
꞊ 4160g the unit of the force we can converted into our required unit.

Tear Strength Tester
Fig 16: Tear Strength Tester

3. Count Measurement:
Count is the numerical expression which expresses coarseness or fineness of yarn. It means that, the yarn count refers how much a yarn is fine or course. We also can say that the yarn count number indicates the length of yarn in relation to the weight.

But according to the Textile Institute, they define yarn count as “Count, a number indicating the mass per unit length or length per unit mass of a yarn”.

Apparatus:

  • Bessley’s balance
  • Template
  • Dead weight

Working Procedure:

  • For count measurement warp and weft way yarn is collected from before washed and after washed Raw Sample & Sample-1, 2, 3, 4, 5, 6, 7.
  • Then the yarn count is measured by Beesley’s balance with the help of template & dead weight.
Bessley’s Balance
Fig 17: Bessley’s Balance

4. EPI & PPI Measurement:
Thread density is the number of warp and weft threads per inch of woven fabric. Thread density is denoted by EPI and PPI. It is very important for GSM and cover factor. But the GSM and cover factor also depend on the thread count. EPI is always greater than PPI.

Apparatus:

  • Counting glass
  • Needle

Working Procedure of EPI & PPI Measurement:

  • For measuring EPI & PPI measurement the fabric sample Before washing & After washed Raw sample & Sample-1, 2, 3, 4,5, 6, 7.
  • Then the EPI and PPI is measured by counting glass with the help of needle.
Counting Glass
Fig 18: Counting Glass

CHAPTER-04

Data Analysis & Result

Appearance:

Raw Sample Washed Sample
Raw Sample of denim Hand Brush,

Destroy, Tagging

(Sample-1)

Hand Brush
Hand Brush,

Pressing Crinkle

(Sample-2)

Pressing Crinkle
Whiskering,

PP Spray, Hand Brush

(Sample-3)

Whiskering
Hand Brush, Destroy,

PP Spray

(Sample-4)

PP Spray

Appearance:

Raw Sample Washed Sample
Raw Sample of denim Hand Brush, PP Spray,3D

(Sample-5)

Hand Brush, 3d
Whiskering, Destroy,

Hand Brush, PP Spray

(Sample-6)

Whiskering, Destroy
Hand Brush, Crinkle

(Sample-7)

Hand Brush, Crinkle

GSM Test Result:

GSM Test Result

Instrument Name GSM Cutter, Electric balance
Comment Standard Sample & Sample-2 has more GSM & Sample-1 & Sample-3 has lower GSM.

GSM Test Result:

GSM Test Result

Instrument Name GSM Cutter, Electric balance
Comment Sample-4 & Sample-5 has more GSM & Sample-6 & Sample-7 has lower GSM.

Graphical Comparison of GSM:

Column charts of GSM measurement
Fig 19: Column charts of GSM measurement

Comment:
Within washed sample in warp & weft direction, Sample-4 & Sample-5 has higher GSM & Sample-1, Sample-3 & Sample-6 has lower GSM.

Tear Strength Test Result:

Tear Strength Test Result

Instrument Name Tearing Strength Tester
Comment Sample-2 has more strength & Sample-1 has lower strength

Tear Strength Test Result:

Tear Strength Test Result

Instrument Name Tearing Strength Tester
Comment Sample-7 has more strength & Sample-6 has lower strength

Graphical Comparison of Strength:

Column charts of warp & weft way tear strength measurement
Fig 20: Column charts of warp & weft way tear strength measurement

Comment:
Within washed sample in warp & weft direction, Sample-2 & Sample-7 has higher strength & Sample-1 & Sample-6 has lower strength.

Count Measurement:

Count Measurement

Instrument Name Beesley’s Balance, Template, Dead weight
Sample Size Half Cotton
Comment Sample-1 has more Count & Sample-3 has lower Count

Count Measurement:

Count Measurement

Instrument Name Bessley’s Balance, Template, Dead weight
Sample Size Half Cotton
Comment Sample-5 has more Count & Sample-4 has lower Count

Graphical Comparison of Count:

Column Charts of warp & weft way count measurement
Fig 21: Column Charts of warp & weft way count measurement

Comment:
Within washed sample in warp & weft direction, Sample-5 has higher Count & Sample-3 & Sample-4 has lower Count.

EPI & PPI Test Result:

EPI & PPI Test Result

Instrument Name Counting Glass, Needle
Comment Sample-1,2,3 has more EPI & PPI & Standard Sample has lower EPI & PPI.

EPI & PPI Test Result:

EPI & PPI Test Result

Instrument Name Counting Glass, Needle
Comment Sample-5 has more EPI & PPI & Sample-7 has lower EPI & PPI.

Graphical Comparison of EPI & PPI:

Column charts of warp & weft way EPI & PPI measurement
Fig 22: Column charts of warp & weft way EPI & PPI measurement

Comment:
Within washed sample in warp & weft direction, Sample-5 has more EPI & PPI & Sample-7 has lower EPI & PPI.

Result

1. Changes in GSM:

Column charts of GSM measurement2
Fig 23: Column charts of GSM measurement

Comment:
Within washed sample in warp & weft direction, Sample-4 & Sample-5 has higher GSM & Sample-1, Sample-3 & Sample-6 has lower GSM.

2. Changes in Tear Strength:

Column charts of warp & weft way tear strength measurement
Fig 24: Column charts of warp & weft way tear strength measurement

Comment:
Within washed sample in warp & weft direction, Sample-2 & Sample-7 has higher strength & Sample-1 & Sample-6 has lower strength.

3. Changes in Count:

Column charts of warp & weft way count measurement2
Fig 25: Column charts of warp & weft way count measurement

Comment:
Within washed sample in warp & weft direction, Sample-5 has higher Count & Sample-3 & Sample-4 has lower Count.

4. Changes in EPI & PPI:

Column charts of warp & weft way EPI & PPI measurement2
Fig 26: Column charts of warp & weft way EPI & PPI measurement

Comment:
Within washed sample in warp & weft direction, Sample-5 has more EPI & PPI & Sample-7 has lower EPI & PPI.

CHAPTER-5

Conclusion
Fashion is today incomplete without denim. Dry process which is most popular for denim garments. At now most of the denim garments are used & dry process rapidly increase day by day.

The effects of dry process/washing on denim under investigation could be realized by the comparison of different sample wash properties namely tear strength, GSM, EPI, PPI, Count. Tear strength, GSM, dimensional stability, and count, EPI, PPI are increased due to required wash treatment. It is further noted that pre- washed jeans are almost stiff and harder than the required washed denim.

It has also been explored that which is cost effective method in dry process technique with can produce fashion apparel and a value added product with a high wear performance. So in order to meet the quick change of customer demand for fashion apparel, dry process/ washing can be an effective way.

The scope of denim dry process is very broad. Only innovative products will be able to open up new markets and new horizons for denim industry. To achieve this it is essential to invest in further research and development. Globalization has opened the door to competition at the highest level. Every industry should now produce products that are best in terms of quality and price. Customers today have a wide range of choices and the one who produces the best quality at a high competitive price will survive and prosper.

References

  1. Mondal and khan, Fashion and Textiles a Springer open journal.2014, 1:19.
  2. Islam, MT. (2010). Garments washing & dyeing (1st ed, PP. 220-222), Dhaka.
  3. Morries, CE & Harper, RJ. (1994). Comprehensive view on garment dyeing and finishing. American Dyestuff Reporter, 83,132-136.
  4. Tyndall, M. (1990). Upgrading washing techniques. American Dyestuff Reporters, 5, 22-30.
  5. Dakuri Arjun, J. Hiranmayee & M.N Farheem, Technology of industrial denim washing: Review, International journal of industrial Engineering & Technology (IJTET), Vol.3, Issue 4, oct 2013,25-34.
  6. Supriya paul “Washing technique of Denim” Fibre to Fashion.com November 2010.
  7. Sanjay “Washing technique of Denim” Fibre to fashion.com December 2010.
  8. https://textilelearner.net/garments-washing-techniques-used-in-bangladesh/
  9. https://textilelearner.net/effect-of-random-wash-on-denim-fabrics/
  10. http://www.slideshare.net/sheshir/denim-washing-34238420?qid=308e9a45-ad6b-498a-851d-c3c87958d19c&v=qf1&b=&from_search=3
  11. https://textilelearner.net/improving-comfort-properties-of-denim-fabric/

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