Latest Dry Washing Techniques in Denim Garments (Part-1)

Latest Dry Washing Techniques in Denim Garments (Part-1)
Asma Akhi
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 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 wash like Hand brush, Grinding, Destroy, Whiskering, PP spray, Tagging, 3D etc.

The distressed jeans that we see around everywhere undergo a wide variety of wet as well as dry 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 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 processing 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 produce 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.
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 places 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) 
 Next part will publish soon.....
 

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