|Cold Pad Batch Dyeing of Cellulosic Fabrics with Fiber Reactive Dyes||Australia||1992-93||Full scale|
MANUFACTURE OF TEXTILES # 6
Most Australian textile mills still use traditional dyeing methods. To enable the dye to be fixed on the fabric, undyed rolls undergo many hours of rough treatment, including the use of a variety of chemicals; wear and tear by machines; enormous amounts of hot and cold water; and treatment with up to 0.5 kilograms of salt per kilogram of fabric.
A 100 per cent cotton fabric with a pre-bleach requires at least eight hours in the dye machine. It is then detwisted, overspread and dried. The fabric is then returned to the spreading unit and resin is applied. After this, the fabric is steamed calendered, spread to width, rolled and packaged for shipping.
In 1958 the Australian Dyeing Company began operations at Clifton Hill, Victoria. Twenty one years later a second plant opened at Seymour. The company is Australia's largest commission fabric dyehouse, processing both knitted and woven fabrics. The company's specialty is dyeing large quantities of knitted fabric, particularly 100 per cent cotton and cotton blends.
In late 1992, the Australian Dyeing Company-which treats 200,000 kg of fabric a week in its two mills - began a restructuring strategy to reduce costs and increase efficiency and productivity. The Program was made necessary by the Australian economy and the influx of clothing imports. The Program investigated alternative dyeing methods, and ways of reducing environmental impact.
Cleaner Production Principle:
New technology, Material substitution
Cleaner Production Application:
Two new processes were introduced viz., cold pad batch dyeing and the use of Cibaron C dyes. Cold pad batch dyeing is a more environmentally-sound and high quality dyeing method. The new dyeing system, specifically designed for dyeing circular knits containing cotton, was developed by Beautech Ltd of Rock Hill, South Carolina, United Sates. It is simple and compact, and the dyeing machine is driven at running speeds of up to 55 meters a minute while reducing water consumption by 88 per cent.
The process involved the purchase of two pieces of special equipment - a padding machine which dyes the fabric and a trickle or rinsing machine. This investment marginally increased the company costs.
As a result of the new process, the fabric undergoes less turbulence and so retains a smooth, uniformly colored appearance with added luster and a soft drape and handle
Environmental and Economic Benefits:
The project resulted in following benefits,
|The process removes salt from the effluent|
|Consumption of water and energy was reduced|
|The volume of effluent generated was reduced|
|The dyeing machine takes up less room on the production floor.|
|The process uses less chemical, and the switch to Cibacron C dyes further reduces the color carried in the effluent|
|Cost is comparable with traditional dyeing but the quality is improved|
|Larger runs of fabric of the same color can be made|
|The company's image has improved as a result of the superior product.|
The economic benefits in the form of cost savings are as follows:
|Net savings||619 200 A$/year|
|Capital investment||400 000 A$|
|Payback period||8 months|
The marginal increase in the company's costs due to the new process were overcome by the company promoting the environmental benefits of the process, which enabled it to charge marginally more for the product to cover the extra costs. After about six months the company began to notice an improvement in the environment and in consumer awareness.
This case study was originally published in the UNEP IE document "Cleaner Production in the ASIA and Pacific Economic Co-operation (APEC) Region. In the process of preparing the document the case study underwent a technical review. Subsequently a second technical review was carried out in September 1998 by Dr. Prasad Modak, Environmental Management Centre, Mumbai, India.