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 polymerizatio polymerization n of vinyl chloride It is hard rigid solid
PVC Hard rigid solid, Can absorb many plasticisers For example cyclohexylisooctylpht halate
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 Polytetrafluoroe thylene (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 moleculess of chlorine molecule
Polytetrafluoroethylene Polytetrafluor oethylene (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-re abrasion-resistant sistant 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 polymerisatio n 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.
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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
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Electrostatic spray assisted vapour deposition (ESAVD) ESAVD) It is used to deposit thin and thick layers on any substance Electrostating 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)
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Chemical and electrochemical electrochemical techniques Anodising
Ion beam mixing
Conversion coating
Pickled and oiled, a type of plate steel coating
Anodizing Chromate conversion coating Plasma electrolytic oxidation Phosphate (coating)
Plating Electroless plating Electroplating Sol-gel
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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
Powder coating or Powder slurry coating Fusion bonded epoxy coating (FBE coating) Molecular beam epitaxy
Paint Sheradizing Enamel paint Silicate mineral paint Polymer coatings, such as Teflon
Spin coating Paper coating Industrial coating [http://en.wikipedia.org/wiki/ Coating]
Roll-to-roll coatings Air knife coating
Gap Coating
Anilox coater
Gravure coating
Curtain Coating
Hot Melt coating
Single and Multilayer Slide Coating
Immersion (dip) coating
Flexo coater
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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, textiles, in Handbook of Technical Textiles A.R. Horrocks, Anand, S. C., Editor 2000, Woodhead Publishing Ltd Cambridge.
