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TEXTILE PROCESSES FOR THE FUTURE by Ing. Jan A. Craamer
HONG KONG CONVENTION & EXHIBITION CENTRE
12 MARCH 2008 TO 14 MARCH 2008
Dear ladies and gentlemen:
Textiles have always played a vital role in human live. Constantly the user requirements are rising in terms of functionality, variety, precision and also the environmental friendliness of textile products.
With the growing world population also the textile consumption will grow, this will mean that the industry that produces textile based products will evolve and grow.
In the last past years increased attention has been directed toward the environment.
Efforts to clean up the environment have been made by government at national, state and local levels by establishing new regulations and guidances.
One of the primary concerns is the water and energy consumption.
Suppliers of textile machines work very closely with the chemical manufacturers. So they developed machines with reduced water and dyestuff consumption and high quality dyestuffs were developed.
So they are often not only suppliers but more often providers of total solutions.
I also think Designers, Textile Consultants and the Fashion industry have to work more together.
Designers explore techniques to create new patterns and finishes. Environmental issues will make designing much more complex because it requires much more knowledge of production processes and chemistry. One of the mayor problems here are due to the complexities of the textile processing chain.
Often the fashion industry needs a colour for the next season and they have no knowledge of environmental implications of their design decisions and fabric specifications. Perhaps to obtain this colour will cause pollution.
Accepting a little change in colour could minimize pollution.
Normally the textile industry is considered a traditional sector. The market is now growing rapidly with innovative textiles and many developments of new products and applications.
The trend is high tech, high performance fabrics with added value in terms of
functionality. Technical Textiles already account for more than 25 percent of all fibres consumed and almost 50 percent of the total textile activity in certain industrialized countries.
The consumption of energy in form of water and electricity is relatively high, especially in processes as washing, de-sizing, bleaching, rinsing, dyeing, printing, coating and finishing. You will also need long process times.
Major portion of water in the textile industry is used for wet processing of textile
(70 %).
Approx. 25 % of energy of the total textile production like fibre production, spinning, twisting, weaving, knitting, clothing manufacturing etc. is used for dyeing.
About 34 % of energy is consumed in spinning, 23 % in weaving, 38 % in chemical wet processing, 5 % for miscellaneous processes.
Power dominates consumption pattern in spinning and weaving, while thermal energy is mayor for chemical wet processing.
Wet processing of the future should be cost effective, environmentally friendly and gentle to the textile material.
Innovative efficient strategies to achieve the goals are needed.
It is often possible for companies to reduce their water and effluent costs 25 % or more.
As input in the textile industry to obtain a finished product you will need:
| Raw Material
| | Carrier (water)
| | Energy
| | Time
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Followed by the process(es) and the output which is waste and the finished product.
The raw material can be:
| Animal
| | Vegetal
| | Mineral
| | Synthetic
| | Half synthetic
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Of this raw material we will produce fibres, filaments and/or yarns and of this ones we will make weavings, knitted goods, non wovens, laminates and others.
So textile is any filament, fibre or yarn that can be made into fabric or cloth, and the resulting material itself. The fabric refers to any material made through weaving, knitting, and bonding or otherwise manufactured.
To give the textile the final aspect and functionalities, it will pass through a large quantity of processes. For example:
| Desizing
| | Scouring
| | Washing
| | Dyeing
| | Printing
| | Coating
| | Finishing
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Further: Grinding, Raughing, Schearing, Stone-wash etc.
Textiles have a large assortment of uses. We can group them in:
| Agrotech
| Agriculture, forestry, horticulture and fishing
| | Buidtech
| Building and construction textiles
| | Clothtech
| Technical components for the clothing and footwear industry
| | Geotech
| Geotextiles and civil engineering textiles
| | Hometech
| Technical components for furniture, interior textiles and floor coverings
| | Indutech
| Filtration and other industrial applications
| | Medtech
| Medical and hygiene textiles
| | Mobiltech
| Transportation textiles
| | Oecotech
| Environment protection
| | Packtech
| Industrial and consumer packaging
| | Protech
| Textiles for personal and property protection
| | Sporttech
| Textiles for sporting and leisure applications
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All this textiles will need a certain appearance, property and functionality.
After producing the textile, we need to prepare it to make it possible to give the functionalities.
Some of those functionalities are:
| Stain- water repellent
| Tents, seats, curtains, furniture, rain coats
| | Flame retardant
| Interior textiles, tents, military clothing, fire-fighters, uniforms
| | Abrasion resistant
| Carpets, tents, seat covers
| | Anti static
| Upholstery, carpets, seat covers, clothing
| | Anti bacterial
| Bedding, medical textiles, socks, clothing
| | Self cleaning
| Tents, awnings
| | UV protection
| Roofs, tents, awnings blinds, curtains, clothing
| | Insect repellent
| Tents
| | Non transparent
| Clothing
| | Wrinkle-free
| Clothing
| | Cut resistant
| Gloves
| | Hi visibility
| Uniforms
| | Chemical protection
| Work wear
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Also often we want to decorate the textile by means of dyeing or printing or we dye or print the filament, the fibre or yarn before we make the fabric.
The dyeing and finishing process generally goes through repeated wet and dry operations.
Almost half of the world's requirements for textile fibres are met by cotton.
We often think that while natural fibres like for example cotton, are better for the environment because these fibres are comfortable to wear and natural.
But Cotton (included organic/bio cotton) is the most polluting product. This is not only due to the use of pesticides, approx. 150 million kg per year, but also to the large consumption of water , to produce 1 kg of cotton you will need up to 20.000 l of water, chemicals and energy.
There are various organic cotton projects since 1989. Organic Cotton is produced without the use of synthetics pesticides, insecticides or fertilisers.
A conventional producer of cotton requires 3000 cubic meters of water per acre more than the organic farmer.
It is common with organic textiles for the manufacturers to only certify the cotton as organic. This means that only the cotton and not the finished garment are certified organic.
After ginning the cotton follows a long way of processes to get the final finished textile ready for the confection.
Sow
| | Ginning
| | Spinning
| | Sizing
| | Drying
| | Warping
| | Weaving
| | Singeing
| | Desizing
| | Scouring
| | Drying
| | Mercerizing
| | Drying
| | Bleaching
| | Dyeing
| | Drying
| | Printing
| | Drying
| | Coating
| | Drying
| | Finishing
| | Drying
| | Thermofixation
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The entire wet process on cotton will use 110-150 liter/kg and on Polyester 50-68 liter/kg.
The high water consumption on cotton is caused principally through the pre-treatment.
There is an increasing demand for sustainable textile solutions. Regulatory standards are becoming increasingly strict. Public awareness is increasing and consumers are becoming more ecologically conscious.
Water is becoming a scarce resource in relation to demand.
Water supply and effluent costs have risen.
In the textile industry we often hear over the Nanotechnology. This technology is more than 100 years old and gives a whole range of clever functionalities and can be used to manufacture new types of fibres or chemicals.
It can also be used for special treatments of textiles for example to impart greater strength, improved crease resistance, improved flame resistance, self cleaning coatings etc.
Plasma treatments can provide new functionalities for surfaces.
The fabrics of the future will be entirely reconceptualized. There will be materials with built in digital devices, materials capable to repair themselves when they are damaged, smart textiles with nanomaterials etc.
But traditional or innovative or added value in terms of functionality will not always reduce the consumption of energy and/or water.
As the textile industry is a big consumer of water I think we have to look for a solution how to minimize, or not to use or only to use the quantity of water you real need.
Some reduction methods are:
Good housekeeping
Process changes
Raw material changes
Product changes
Why should we not apply nano technology but as a Nano-process in the whole chain of wet textile processes. To start from pre-treatment and ending with finishing.
I think in the textile industry we have not only to modify technology, machines, chemicals and dyestuffs to save some litres of water or energy but we have to change the processes completely and if possible without the use of water or only micro- or nano quantities !
This will also result in zero waste water and a minimum of energy consumption.
We have to analyse the processes where we can deposit water in form of a spray with micro, nano or pico drops of liquid and so be able to control the deposit of liquid we need on the textile to obtain the desired colour and functionality.
One of this technologies to deposit nano- or pico- volume drops you will find in the Ink Jet Technology which is already used in textile printing.
Here you will find different systems:
Continuous Ink Jet
Drop on Demand
Valvejet
But these inkjet systems are not appropiate for open industrial continuous textile finishing of large runs !!!!
The water consumption of the whole process of dyeing, printing, coating (2x) and finishing on cotton will be for
the traditional process 43715 liter (=111 liter/kg) and
for the continuous DSDS 738 liter (=2.4 liter/kg).
Processing time traditional 700 minutes for 800 meters and for DSDS 40 minutes for 800 meters.
In the traditional processes not all the dye is fixed to the fibre during the process. The reactive dye used for cotton has the poorest fixation rate on the fibre.
Here you see some 100% Polyester coloured textile with Dispers dyestuffs on a DSDS system.
Here 100 % Viscose laminated with paper and afterwards coloured with Pigments on a DSDS System.
Here 100% Viscose coloured with pigments on a DSDS System.
Here a finished Black-Out 100% Polyester coloured with Pigments on a DSDS System.
The advantages of a DSDS-System are:
Up to 80 l/kg less water consumption in the whole wet process (cotton).
No waste water in the wet processes, dyeing, printing, coating, finishing.
No waste chemicals.
No waste textiles.
No stop times between processes
Up to 1627 KWh less energy consumption for the whole wet process (cotton).
Dyeing, printing, coating and finishing possible on laminated textiles.
Dyeing, printing and finishing possible on coated textiles.
No need of stock of finished material.
Very short lots possible.
Dyeing on both sides at the same time of the textile in different colours.
Finishing on both sides at the same time with different functionalities.
Reduction of processing time.
CONCLUSIONS
The trend in the textile industry is to save energy and water, to use effective chemicals and dyestuffs and further process optimization.
Textile machine builders have already been working on improvements for preparation and pre-treatment processes like the separation of streams for the disposal of industrial effluents, which facilitates recycling of less polluted water.
Producers of Dyeing machines looked for reduced energy and water, chemicals and dyestuffs consumption.
We still need more synergy between the Garment Industry, Textile industry and Textile Consultants.
The key to successfully reducing water and chemical use is to know exactly how the processes are working and what we are doing.
In the traditional processes the waiting times and distances between the processes are too long. This costs much money and energy (transport).
Often we are using dyestuffs which are not necessary for that specific case and we could for example change the reactive dyestuff for a pigment system.
We replaced a quantity of reactive dyed cotton which was used for book coverings, with pigment systems and the fastness was excellent for this purpose. Also we changed dispersed dyed Polyester for Black-out curtains by a pigment system and also here the fastness was excellent for this article.
So there are a big quantity of articles where you can use nowadays a pigment system with acceptable fastness.
While a finished textile is build up of a large chain of processes as we saw in picture 7
a reduction in the frequency of reprocessing through a reduction in the failure rate
is one of the most important measures you can take to reduce water, energy,
dyestuffs, chemicals and time, without any costs.
Still today I met Textile mills with >25 % of reprocesses !
Resume:
Time saving
High speed processing of unit operations.
Reduction in waiting time between unit operations.
Elimination or merger of unit operations.
Reduction in energy use per unit operation through an improvement in productivity.
Labour saving
Implementation of automation.
Strengthening colorimetric management.
Reduction in the frequency of reprocessing though a reduction in the failure rate.
Energy saving
Reduction in the bath ratio.
Reduction in treatment time.
Reduction in margin of temperature rise.
Re-examination of dyeing method.
Reductions of energy costs.
Water saving/waste water reduction
Reduction of the bath ratio.
Reduction of water costs/waste water costs.
Space saving
Construction of modern factories.
Improvements in factory-wide energy saving effects.
We start implanting new Process-Technologies, for the wet textile processes, and according to all known process possibilities, this will be a modern factory wherein all wet processes, like pre-treatment, dyeing, printing, coating ad finishing are done continuous , in the full width and velocities up to 100 meters/minute, with nano deposits of liquid in the quantity the textile needs and we need to obtain the colour and/or functionality and no more.
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