Coating of Textiles
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Coating of technical textiles Description of coating application to produce Technical Textiles Dr Muhammad Mushtaq Mangat www.mushtaqmangat.org
Chemistry of coated textiles
Spread of a viscose material to develop certain properties
Viscose material is coated and dried/cured for long lasting attachment
Coating is limited to linear to linear polymers, on drying they are converted into hard film
All thermoplastic polymers having long chain long chain linear molecules
Few have the ability to crosslink
Polyvinyl chloride (PVC) Made by free radical polymerization of vinyl chloride It is hard rigid solid
PVC
Hard rigid solid,
Can absorb many plasticisers
For example
cyclohexylisooctylphthalate
Such addition creates new avenues of its application
This unique property increase its worth
PVC Coated tarupaulin Gives hardness and used for protection
PVC coated PET
Used as Technical Textiles
More rigid and hard still flexible able to adapt various shapes
Polytetrafluoroethylene (PTFE)[1]
PVDC is very similar to PVC
Made by using emulsion polymerisation of vinylidene chloride
Low gas permeability
More expensive than PVC
Give better flame resistance due to 2 molecules of chlorine
Polytetrafluoroethylene (PTFE)
Developed by Du Pont in 1941Made by polymerization of tetrafluoroethylene
Used as protective material from sun light
PTFE applications Water and repellant
Highly thermal resistance (250C)
Inert to most common solvents and chemicals
Can be degraded by strong
Expensive comparatively
Rubber [1]
Natural rubber a linear polymer of polyisoprene
Obtained from the sap of many plants
It can be used directly for coating
Natural polymer contains unsaturated double bonds along the polymer chain
Rubber Modification [1]
It can be crosslinked with sulphur
It is called vulcanisation,
Gives abrasion-resistant films or hard ebony-like structures.
Flexibility depends upon the amount of crosslinking
Prone to oxidation and ozone attack
http://www.archerrubber.com/
Styrene–Butadiene Rubber (SBR) [1]
Is made by emulsion polymerisation of styrene and butadiene
Application is similar to natural rubber
Less resilient than natural
Superior weatherability and ozone resistance
More than 50% of all rubber used is SBR
Application of SBR coated cloth
Nitrile rubber [1]
Nitrile rubbers are copolymers of acrylonitrile and butadiene
Highly oil resistance,
Excellent tensile strength and resistance to abrasion
Used for fuel tanks, not good for tires
Butyl rubber [1]
It I copolymers of isobutylene and isoprene
Developed by BASF in 1931
Used as fuel additive, explosive, sports items, chew gum, tires, coating material
Many more coating material
Chlorosulphonated polyethylene (Hypalon)
Silicone rubbers
Polyurethanes
Glass wool coating
Teflon
Wax
Aluminized kevlar
Elastomer coating
High temperature coating
And many more…
Coating techniques [1]
Lick role
Fabric is passed over a roller, which is dipped in solution
Knife coating
fixed knife is used to spread solution
Thickness depends upon the gap between knife and fabric
• knife on air
• knife over table
• knife over roller
• knife over rubber blanket.
[1]
Metalorganic vapour phase epitaxy
MOVPE is a process in which vapors of chemicals are deposited on the surface of fabric
Quite complex process
semiconductor multilayer structures
[http://en.wikipedia.org/wiki/Coating]
Electrostatic spray assisted vapour deposition (ESAVD)
It is used to deposit thin and thick layers on any substance
Electrostating spraying technique is used
Chemical reaction occurs during spraying
Following products can be made: Thermal barrier Protection of photovoltaic panels Electronic components Biomedical coatings Glass coatings (such as self cleaning) Corrosion protection coatings
[http://en.wikipedia.org/wiki/Coating]
Physical vapor deposition
Cathodic arc deposition
Electron beam physical vapor deposition (EBPVD)
Ion plating
Ion beam assisted deposition (IBAD)
Magnetron sputtering
Pulsed laser deposition
Sputter deposition
Vacuum deposition
Vacuum evaporation, evaporation (deposition)
[http://en.wikipedia.org/wiki/Coating]
Chemical and electrochemical techniques
Anodising
Conversion coating
Anodizing
Chromate conversion coating
Plasma electrolytic oxidation
Phosphate (coating)
Ion beam mixing
Pickled and oiled, a type of plate steel coating
Plating
Electroless plating
Electroplating
Sol-gel
[http://en.wikipedia.org/wiki/Coating]
Optical coatings
Antireflection coating, to reduce reflection
A mirror coating to enhance it
[http://en.wikipedia.org/wiki/Coating]
Others Dip-coating
Epitaxy (vapor phase, liquid phase)
Vitreous enamel
Paint
Enamel paint
Silicate mineral paint
Polymer coatings, such as Teflon
Powder coating or Powder slurry coating
Fusion bonded epoxy coating (FBE coating)
Molecular beam epitaxy
Sheradizing
Spin coating
Paper coating
Industrial coating
[http://en.wikipedia.org/wiki/Coating]
Roll-to-roll coatings
Air knife coating
Anilox coater
Curtain Coating
Single and Multilayer Slide Coating
Flexo coater
Gap Coating
Gravure coating
Hot Melt coating
Immersion (dip) coating
[http://en.wikipedia.org/wiki/Coating]
Knife-over-roll coating
Metering rod (Meyer bar) coating
Reverse Roll coating
Roller coater
Rotary screen
Silk Screen coater
Slot Die (Extrusion) coating
[http://en.wikipedia.org/wiki/Coating]
Spraying
High velocity oxygen fuel (HVOF)
Plasma spraying
Thermal spraying
Plasma transferred wire arc thermal spraying
References
[1]Hall, M.E., Coating of technical textiles, in Handbook of Technical Textiles A.R. Horrocks, Anand, S. C., Editor 2000, Woodhead Publishing Ltd Cambridge.
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