A2 Textiles: A2 Textiles The Impact of Modern Technology and Biotechnology on
Textile Processes Introduction: Introduction Many natural fibre dyeing and finishing processes are not environmentally friendly.
They involve use of chemicals which cause pollution when waste water is put into rivers.
Manufacturers are pressurised by the government to reduce levels of pollution.
In this section we will look at
* Fabric finishing processes
* Improved plant varieties
* Dyeing and finishing
* Recycling Fabric Finishing Processes: Fabric Finishing Processes Fabric finishes can change the handle, texture and performance of fabrics.
Anti-static and shrink resist have been around for years.
New ways of producing finishes are being developed to improve fabrics and reduce pollution.
We will look at:
i) Shrink resistancy
ii) Coating fabrics
iii) Anti-bacterial finishes
Shrink Resistancy: Shrink Resistancy Wool fibres shrink and felt when washed.
To prevent this finishing processes are used:
* Wet finishing for woven wool.
Environmentally friendly. Dried naturally. Called London Shrinking. Subsequent washing causes shrinking and felting so must be dry cleaned.
* Chemical shrink finishing. Uses chlorine which is an environmental hazard. New finishes are being developed. Shrink Resistancy: Shrink Resistancy New Shrink-Resistant Finishes –Surrounding Fibres
Surround wool fibres with synthetic polymers to stop felting.
Soft lustre is a finishing process which uses silicone resulting in soft, smooth, lustrous yarn that dyes well and can be machine washed.
Machine washable wool can be finished with Telflon which doesn’t affect handle, drape or breathability. Stops it pilling too.
Shrink Resistancy : Shrink Resistancy Inter Fibre Bonding
Soft polymer applied which sticks to wool fibre surface which bonds fibres together.
Can be machine washed. Shrink Resistancy : Shrink Resistancy Superwash
For jumpers of socks made from shrink resistant knitwear yarns.
Term to show that it can be machine washed.
Can be any process used but must be high level of shrink resistance, colourfastness and after wash appearance. Coating Fabrics: Coating Fabrics Originally rubber, oiled or waxed, but not breathable.
Used for protection against weather.
PVC, silicone and polyurethane first used.
Modern synthetics are fluorochemicals, chlorofibres or silicone which are microporous and breathable (since 1985). Coating Fabrics: Coating Fabrics Application
Layer of synthetic polymer on back or front of fabric.
Can be heavy or thin coating. Thinner is more flexible.
Coatings can make fabric reflective, iridescent, papery, high-gloss, neon or holographic. Coated Fabrics: Coated Fabrics Coated Fabrics: Coated Fabrics Transparent coatings on fine fabrics = fragile but strong, durable fabric.
High performance wear can be coated with polyurethane. Polyurethane is microporous or hydrophilic = breathable.
Modern coated fabrics are wipe clean, scratchproof, breathable and give protection. Coated Fabrics: Coated Fabrics Used for:
* Protective clothing
* High visibility garments
* Handbags, luggage
* Furniture and car seats
* Floor and wall coverings
* Conveyor belts, inflatables
* Shower curtains, blinds Anti-Bacterial Finishes: Anti-Bacterial Finishes Copies linen ie non allergenic so germs can’t spread, releases dirt and improves anti-bacterial effect with washing – used for hospital sheets and bandages.
Nowadays anti-bacterial finishes are used for medical and sportswear.
Works by stopping growth of microbes. Trilosan (a chemical) is added to surface of fabric. Anti-Bacterial Finishes: Anti-Bacterial Finishes Anti-Bacterial Finishes: Anti-Bacterial Finishes Used to protect garments / shoes from bacteria for lifetime of product.
Must have good anti-microbial performance after at least 50 washes.
Some finishes are not applied to surface but to fibre itself – doesn’t wash out.
Benefits – control odour, stop skin irritation / infection, stop fabric discolouring / deteriorating. Biotechnology: Biotechnology Farming with bugs!
Uses natural biological processes to aid manufacture.
Eg in food manufacture fermentation is used to make bread, beer, cheese, wine, yoghurt.
Used in textiles for 100 years eg amylase used to remove starch from woven fabrics. Biotechnology: Biotechnology Use of enzymes
Enzymes are chemicals that speed up chemical processes but aren’t destroyed.
Needed for digestion, growth, repair, energy.
Used in biological washing powders since 1960’s.
These enzymes get rid of stains at lower temperatures – saves energy and protects fabric.
Biotechnology: Biotechnology New Developments
Fibre preparation , fabric finishing and aftercare.
Benefits – less energy used, speeds up production of processes, based on renewable raw materials, reduces environmental pollution.
Biotechnology: Biotechnology Biological wool shearing
Being done in Australia.
Artificial growth factor injected into sheep to interrupt hair growth.
After a month breaks appear in wool fibre and fleece can be pulled off.
Takes half the normal shearing time. Improved Plant Varieties: Improved Plant Varieties Cotton
Uses a lot of pesticides.
Organic cotton would reduce pollution.
Developing cotton plants with insect resistance would reduce pollution as pesticides wouldn’t be needed.
Bio pesticides have been developed to replace chemical ones and genetic modification is being used to produce high performance cottons that are stronger, longer, more insulating and look better.
A futuristic idea is to produce customised cotton or growing polyester cotton!
Improved Plant Varieties: Improved Plant Varieties Naturally grown coloured cotton
Can already produce red, green, brown, grey, orange, yellow and mauve – same way that gardeners produce coloured flowers.
Trying to make blue and intense colours.
Will one day replace need to bleach and dye. Naturally grown coloured cotton: Naturally grown coloured cotton Improved Plant Varieties: Improved Plant Varieties Biopolymers
Synthetic polymers are not biodegradable.
Biopol is the first biodegradable polymer.
It is a natural – British – polyester produced by fermentation of a sugar.
Glucose is converted into polyhydroxybutyrate (PHB).
Can be used for medical and surgical implants. Improved Plant Varieties: Improved Plant Varieties Biopol
Is flexible, strong.
Can be blow moulded, injection moulded, extruded.
Used for shampoo bottles, paper coating.
Used instead of PET bottles as it’s a good barrier.
Used for fishing nets which are environmentally friendly.
Can be recycled or made to rot by composting or in a landfill site. Biopol: Biopol Improved Plant Varieties: Improved Plant Varieties Spider Silk
Silk of orb weaving spider is one of the world’s strongest fibres – very strong and elastic.
Spider silk is as strong as steel and can be a mile in length – could be used instead of Kevlar.
Difficult to get the spider to spin to order.
Genetic engineering could help.
DuPont is making biosilk by putting silk genes into yeast or bacteria.
This enables manufacture of silk proteins which are dissolved in a solvent then spun as biosilk fibres.
Could be used for engineering, satellites or aircraft.
Research is being done in USA to milk spiders for their silk for bullet proof vests. Dyeing and Finishing Processes: Dyeing and Finishing Processes Chemicals are used to dye and finish.
The environmentally unfriendly processes are:
Removing colour and pesticide from waste water.
The toxic heavy metal compounds used in dyeing.
Chemicals used in finishing processes.
New, environmentally friendly processes are being developed.
For example scouring and bleaching of fabric using an enzyme to remove hydrogen peroxide used in bleaching from waste water. Dyeing and Finishing Processes: Dyeing and Finishing Processes New environmentally friendly processes.
Naturally grown cotton that is permanently dyed (to stop dyes running in the wash).
Colour run system which uses an enzyme to bleach the dye in the wastewater but not the garment. Dyeing and Finishing Processes: Dyeing and Finishing Processes Biostoning
Cellulase enzymes can be used instead of pumice stones to produce stone washed denim.
Pumice stones damage the denim – especially hems and waistbands – and the machinery.
Benefits of biostoning include:
* Less damage to clothes and machines.
* Products come out the same.
* More denim produced in a shorter time.
* Reduced labour costs.
* Reduced environmental damage – abrasive sludge. Dyeing and Finishing Processes: Dyeing and Finishing Processes Biopolishing
Cotton isn’t smooth, it is covered by tiny protruding fibres which can bobble with wear. This is called pilling.
A new biological process has been designed to stop pilling.
An enzyme treatment called Cellusoft cuts of the protruding fibres leaving soft, shiny fabric.
For wool a protease enzyme treatment has been developed.
Biopolishing can be used for Tencel and Lyocell.
Dyeing and Finishing Processes: Dyeing and Finishing Processes Biological security markers to aid fibre identification.
Fraudulent labelling of country of origin and fibre content is a crime eg may be labelled as cashmere but is really yak.
To combat this Biocode (a UK company) have developed a method of detecting fibres.
These are sensitive antibodies that detect foreign substances. It can be detected by people using antibody kits. It is being used for protecting brand named products.
Recycled Textiles: Recycled Textiles Pollution is caused by bleaching, dyeing, finishing and the production of waste materials.
Recycling is not easy as products are often made from blended fibres.
100% natural fibres are easier to recycle. Recycled Textiles: Recycled Textiles Natural fibres
High quality, fashionable garments that use less energy to make and cause less pollution are available. They are made from recycled fibres.
Recycling is done by tearing clothes into fibres called shoddy using a rag pulling machine. Shoddy is then blended, carded, spun and knitted or woven into fabric.
Recycling fibres reduces pollution by:
Less virgin wool is brought over from Australasia
Less scouring (removing dirt from wool)
Less carbonising (acid treatment to remove impurities from wool)
Less dyeing – less water pollution. Recycled Textiles: Recycled Textiles Synthetic Fibres
Can take hundreds of years to break down.
Polyester can be recycled – made from soft drinks bottles.