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Uses of laser technology producing ‘greener’ denims

The demand of denim clothes in the world is increasing day by day. Especially for the young generation, this denim or jeans use is quite noticeable. But instead of solid color denim, the world’s young generation is heading towards washed, designed, faded, soft, printed fashionable denim. Considering this demand of consumers, numerous denim washing (finishing) industries have been built. Washing industry requires lots of water and chemicals for garment treatment. There are different types of effects such as tagging, grinding, destroy through PP spray, bleach, acid, stone, enzyme or hand sands. Since the buyer is quite aware of global warming and ecological hazards, new water-saving laser technology is being used worldwide in washing. In this situation, Bangladesh is not behind from the touch of this technology. For the last several years, the washing factories of Bangladesh are making green denim products.

Figure 1: Various laser printed denim jeans.
Figure 1: Various laser printed denim jeans.

Today’s world is facing unclean environment and limited drinking water problem. In denim finishing (washing) industry, drinking quality water is used extensively but scientists want to reduce it up to minimum 70% in the industry in future. As a result, specialists for denim washing plants discovered green concept technology. The first demonstration of laser took place in Levi’s research laboratory in California with American government support in 1960. Then lot of companies jointly had developed it and is developing now. The CO2 laser, commonly, used in industry today for the processing of textiles.

Technical directions of green concept in denim industry
To make fading of color, laser is applied in denim or jeans garments instead of Potassium Permanganate (PP) spray. This ray is used to enhance any type of design on denim cloth according to demand. Besides, ozone formula is used instead of chemical bleaching for water reduction.

Basically, 3 technical processes are being used in green concept.
1. Laser blasting for dry process
2. Ozone treatment for dry and wet process
3. E-flow for washing

1. Laser blasting for dry process

A Laser blasting or engraving system generally contains a system for delivering the beam, the work bed on which the materials to be processed are placed, fume extraction systems and a housing which encloses the system.

Laser is an energy source whose intensity and power can be precisely controlled. It is produced by combination of CO2 +DC current. The laser is applied on the fabric according to the require intensity. There are three parts in laser m/c- computer part, siler part (chemical section) & laser part. The work bed may be of honeycomb structure or metal slats or metal rods (also containing tiny holes).

Figure 2: Laser printing design in the computer.
Figure 2: Laser printing design in the computer.

Firstly the design is made up in computer by Adobe Photoshop and then this design is transferred to the laser machine placing the garments on the cutting bed. After according to the requirement intensity, the laser ray applied on the focused design portion. This laser burns the surface of the fabric. The fume extraction takes place from below the work piece and the spaces or holes enable the gases to circulate and for processing debris to be sucked away from the work area. Whisker, hand sand, grinding, fading, cut hole, image printing etc. can be done by laser blasting process.

Special requirement for laser

Fabric has to be minimum 98% Cotton. (Polyester fabric is very difficult to use with laser). Indigo fabric is very good for laser.

2. Ozone fading technology

Ozone air (natural gas) typically acts as a mild bleaching agent as well as a sterilizing agent. It will change color blue to white. In this technique of denim washing, the machine takes air from the atmosphere, filters it and separates it into its essential components. Oxygen (O2) is thus purified and enriched and the O2 molecule is transformed into an O3 molecule with high voltage, generating ozone gas. The ozone obtained is injected into the tumbler that washes the jeans. It naturally ages the denim, which whitens as if sun bleached.

Figure 3: PP spray unit.
Figure 3: PP spray unit.

At the end of the bleaching cycle, the ozone is sucked from the drum and re-mixed with atmospheric components to become oxygen before being released into the air. Laser manufacturer company Jeanologia emphasizes that this type of washing is “a natural and non-polluting treatment.” Dry and wet techniques are included with Ozone process.

Summary of savings on energy and water

Conventional Ozone        Savings %
Water usage (gallons)            700            350           50%
Energy usage (kcal)          73,421         28,632           61%

Special requirement for ozone
Ozone reacts with indigo fabrics only.  In wet process, water percentage has to keep correctly.

3. E-flow

E-flow takes the air from the atmosphere and transforms it into nano-bubbles. In this process, 70% water and 50% chemicals can be reduced. Recently Jeanologia has developed it & their marketing slogan is “water is over, air is the future”.

Spain based laser manufacturing renowned company Jeanologia recently has launched a laser machine that can produce about 100 or 200 of jeans per hour whereas manual scraping produces only 10 units per hour, sandblasting 30 and spray 60. This will help garments to save 62% of power, 67% of water (liters), 85% of chemical as well as 55% of production time.

Every year about six billions units of jeans are produced where 70 liters of water, 1kw/h & 150gms of chemicals are used for per jeans that means in total 420 million m3 of water, 6 billion kw/h and 900000 tons of chemicals. If the owner of textile industry starts using this new technology, the equivalent of 2 years of human consumption of water in Paris and 2 years consumption of electricity in Nepal could be saved per year, as well as 720,000 tons of chemicals products.

Figure 4: Video showing how a jeans in printed by laser technology.

Md. Nurul Amin, Marketing Director of Hams Washing & Dyeing Ltd. said, “Buyers and consumers, especially from Europe and America are concerned about the environment-friendly and water efficient aspects of the laser technology. Not only laser but also ozone is the fastest growing and accepted technique in the denim market as this technology has made denims go green. The technology is gaining popularity in the country’s RMG sector day by day.”

Advantages of laser

It consumes less water, energy and time, no hazardous, environment friendly and requires no chemical. Any complex design at any place can be created. Accuracy, good quality & production are high. Less manpower required.

Present status of denim market in Bangladesh

Nowadays, jeans are popular to everyone young to old, cowboy to rockstar, supermodels in every sectors of people. As a result, the latest data of Dhaka Int’l Denim Shows, around 30 million yards of denim is produced per month by 26 factories in Bangladesh. In terms of denim sales, US and UK are two major markets of the country.

The Bangladesh Export Promotion Bureau estimates the country exported finished denim products worth USD 430 million to the US and Euro 1.8 billion worth of products to the European Union in 2015. Bangladesh is now the world’s first denim exporter to Europe & third largest to US market after China and India. In 2015, Bangladesh held 22.88% market share in the EU and 11.35% in the US denim markets. The global denim industry is estimated to be worth USD 64.1 billion by 2020. Currently, about 1.8 billion pairs of denim trousers worth USD 51 billion are sold annually worldwide.

More than 5 new factories will be added in the coming year. The producers of Bangladesh have set a target to export USD 7 billion of denim by 2021 while the country is exporting USD 2 billion now.

Figure 5: Laser is being used to produce greener Denim.
Figure 5: Laser is being used to produce greener Denim.

Mahabubur Islam, Technical Manager of S. F. Washing Ltd. said, “There are approximately 200-400 small and large denim washing plants in Bangladesh. It requires less number of workers, chemicals and water. In future, the use of this technology in Bangladesh will increase further.”

Saiful Belu, Senior Production Officer of Ananta Casual Wear Laundry Ltd. (Ananta Group) said, “Modern laser rays are required for printing, cutting or engraving any type of design at denim garments which can’t be done accurately by conventional method”.

Laser demand in the world
Bangladesh exports washed blue denim trousers, denim skirts, jackets, suit type coats, playsuits, sunsuits etc. to the foreign markets. According to the JACK & JONES low impact denim statement, “They saved 25 million liters of water around the world in 2012”. Moreover, ‘One Glass, One Garment’ finishing treatment concept of Spanish sustainable technology firm Jeanologia is also getting popularity.

According to Jeanologia, today, around 25% of global jeans production uses laser technology and is set to reach 50% in the next two years. Moreover, currently more than 180 laser machines are being used in Bangladesh’s factories. Washing experts and marketers think that the number will cross 500 in the next two years.

Laser technology is another name for sustainable finishing in the country’s washing sector. It will completely change the future of denim sector. The country’s leading washing expert expects the domestic denim sector will go one-step further in future with this environmentally advanced technology.

If anyone has any feedback or input regarding the published news, please contact: info@textiletoday.com.bd

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