Coating Application in Textile

Coatings and their applications in textiles G. Bu Buyle yle – MI MIIC ICS S 201 2012 2

Texti Te xtile les… s… va vario rious us ap appl plica icati tion ons s

G. Buyl Buyle e - MI MIICS ICS - 20 2012 1203 0314 14

Outline 

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Introduction Centexbel Basic textile coating Advanced coating techniques Examples of applications

G. Buyl Buyle e - MI MIICS ICS - 20 2012 1203 0314 14

Acknowledgements 

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Research at Centexbel on topic “smart textil tex tiles” es” enab enabled led via severa severall research research projects Acknowledgement of the funding agencies on different levels: 

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Regional: IWT National: BELSPO European: FP6 and FP7 programmes

Acknowledgement of the numerous partners (both from academia and industry) worked with in these projects G. Buyl Buyle e - MI MIICS ICS - 20 2012 1203 0314 14

Outline 

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Introduction Centexbel Basic textile coating

Advanced coating techniques Examples of applications

G. Buyle - MIICS - 20120314

Centexbel: centre of competence 

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collective research and technical centre membership organisation 

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Belgian textile companies associated (international) member companies and organisations

staff 

140 skilled and highly educated men and women


Research groups 

Three domains: 

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Functional thermoplastic textiles : compounding, extrusion, (bio) polymers, nano-additives, textile reinforced composites,… Textile functionalisation and surface modification: coating & finishing, sol gel, plasma treatment, lamination, hot melt,… Health, safety & security : medical and bio-functional textiles, smart textiles, thermo-physiological comfort,…


textile functionalisation and surface modification

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Coating, finishing and surface modification for new and superior functional performance textiles with multifunctional properties modifying textile surfaces using coating, plasma functionalisation, UV curing, hot melt, sol gel,… new sustainable technologies G. Buyle - MIICS - 20120314

Testing laboratories Laboratories (ISO 17025 accredited): 

Physical: 

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Chemical: 

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E.g. chemical analysis, microscopy

Microbiological: 

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E.g. breathability, outdoor ageing

E.g. antimicrobial effect, biodegradability

Fire: 

E.g. burning behaviour, smoke toxicity

Centexbel is recognized by large distribution companies, consumers’ associations, OEM’s, … G. Buyle - MIICS - 20120314

(pre-)standardisation

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Active participation/leading role in standardisation committees (CEN & ISO) Sector operator Centexbel leads Mirror committees WG31 “Smart Textiles” (in CEN TC248) G. Buyle - MIICS - 20120314

Outline 

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Vision: textile as flexible carrier for offering specific functionalisation(s) Light Reflection Fire Retardant Biocompatible Anti abrasion Breathable Self cleaning Water repellency Fragrance release Electrically conductive Thermal insulation Antibacterial Bioresponsive G. Buyle - MIICS - 20120314

Three levels of coating fabrics Fabric level

Traditional coating

Yarn level Filament/ fibre level G. Buyle - MIICS - 20120314

“Advanced” techniques e.g. plasma coating

Materials 

Textile coating typically comprises 2 parts: 

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Binder for durability (washing, abrasion) Additives for functionality

Materials for binder: 

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Example nanoparticles for textile coating

Polyacrylate Polyurethane Polyvinylchloride G. Buyle - MIICS - 20120314

NP Matrix/binder

Example: lamination of membrane in-between two textile fabrics Knitted fabric Coating Membrane

Coating Woven fabric


Example: Fire Retardant coating for carpet

Coating application G. Buyle - MIICS - 20120314

Carpet coating analysis via XRF mapping Carpet structure

FR additives

Ti

Sb

S

Br


Example: PVC coated polyester fabric Textile architecture


Tarpaulins for trucks

Classical techniques: 

Wet techniques: 

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Formulation: solvent or water based Application unit: padding/ immersion, knife coating, transfer coating, foam coating,… Typical add-on: 20-50g/m2

Multitude of advantages: 

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Robust Large scale Relatively simple equipment G. Buyle - MIICS - 20120314

Immersion

Mayer bar

Classical techniques: typical coating line

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Wet technique → need for ovens → energy issue

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“Long” → only profitable for large batches


Search for novel techniques because of drawbacks/limitations 

Drivers: 

Economy: ability to run smaller production batch sizes → “digital” reduce energy use → “dry techniques” Performance: minimal thickness or add-on accuracy, uniformity Ecology: more healthy products (e.g. prevention of phthalates) use of bio-based and/or bio-degradable 

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Hot melt: basics 

Hot melt: 

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100% system (granulates, blocks,…) Melting of the polymer Application as melt Solidifying → Coating Materials: PE, PP, PES, PA, EVA, TPU, silicone Source: www.robatech.com

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Two main groups (curing based): 

Thermoplastic hot melts: Solidifying via cooling Reactive hot melts: Solidifying via cooling + drying or UV irradiation 

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UV curable coatings IR source

IR

UV

UV source

Textile substrate

Coating application Curing G. Buyle - MIICS - 20120314

Polyolefine-coatings (1/2) 

POD = polyolefine dispersion in water, suitable for “standard” application techniques


Source: Dow

Polyolefine-coatings (2/2) 

PODs have unique advantages: 

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Functionalisation: 

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Solvent-free solution High solid content (typically 40 to 55 wt%) Functionalisation possible Possible to mix in active components Examples: FR, antimicrobial, conductive

Goal: replace some of the PVC applications (prevention of phthalates) G. Buyle - MIICS - 20120314

Outline 

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Advanced coating techniques 

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ALD Evaporation

Magnetron sputtering Atmospheric Plasma coating


ALD technique - introduction 

Deposition via ALD: Atomic Layer Deposition Process at low pressures (in vacuum chamber) → highly conformal coatings 

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Standard technique

ALD technique

Advantages for textile: Example: ALD deposition on cotton fibres → Extremely high conformality → Possibility to have anti-corrosion layer 

Cross section: cotton fibre with ALD coating G. Buyle - MIICS - 20120314

Source: Hyde et al.

ALD deposition into non woven substrate 

Example*: ALD deposition on non woven (NW): 

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Al-oxide (Al2O3) deposition PES NW cube dimensions: side = 3.5cm XPS analysis: penetration of coating ?

Outside

Inside

Deposition is uniform throughout the sample G. Buyle - MIICS - 20120314

* TMMETACEL, in collaboration with UGent - www.ald.ugent.be


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ALD Evaporation Magnetron sputtering Atmospheric Plasma coating


Evaporation for textiles  

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Evaporation is feasible on textile Use of existing (large scale) equipment Offered via toll manufacturing Applications: UV and/ or IR reflection layers Conductive layers Antimicrobial layers …    


Source: Alupa


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Magnetron sputtering on textile 

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Commercially available: silver coated PA monofilament Use: 

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Textile electrodes Antimicrobial textile

But… cost factor !!!


Bron: Tersuisse Multifils

“Most Luxurious Necktie Ever ? ...” “Retailing at 7,500 Swiss francs (or roughly $8,450) apiece, each tie will comprise 8 grams of 24-karat gold,…”

Gold coated silk


Source: www.ecouterre.com


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Atmospheric plasma coating Plasma source Precursor Plasma

Textile substrate   

Plasma + Precursor (chosen according to the desired properties) Coating possible → permanent change of the surface properties Crucial: interaction between precursor, substrate and plasma G. Buyle - MIICS - 20120314

Atmospheric plasma coating equipment*

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Key properties: 

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For wide substrates (up to 40 cm) Corona + possibility to add liquid precursor G. Buyle - MIICS - 20120314

* Available through cooperation with Univ. College Ghent

Example: surface analysis antimicrobial coating 

XPS and ToF-SIMS → chemical composition Size = 5x5mm2, color = specific for chemical group, PES fabric

Untreated G. Buyle - MIICS - 20120314

“Badly” treated

Uniformly treated

Outline 

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Electrical conductivity: integration of carbon nanotubes in textile coatings 

Acrylic based coating with increasing CNT content: 

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Highly flexible textile coatings Conductivity starts at 4 wt% CNT, resistivity down to 60 8000

) 7000 m h 6000 O ( 5000 y t i 4000 v i t 3000 s i s 2000 e R1000 0 0 2 G. Buyle - MIICS - 20120314

4

6

wt % CNT

8

10

Ω

(!)

SEM pictures: coated fibre with well distributed CNT network


Application: Integration of solar cells in textile 

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Solar cells require (highly) conductive layers Potential application: directly coating on textile materials 

e.g. tents, screens, backpacks, garments


Coated fabric

Flexible textile solar cell

Application: conductive yarn via CNT, used in antistatic fabrics


Patent pending (EP2011002735)

Antistatic fabric

Self Healing properties 

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Several principles exist for reaching self-healing (mixing of substances when crack/scratch appears) Own development for textile: Freshly scratched


After self-healing

Abrasion resistance via sol-gel chemistry for textiles 

Characteristics: 

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Existing technology for coating on glass surfaces Sustainable layers of eg. Si-O-Si (~glass) Adapted to textiles (lower curing temperature) Nano-porous surface, thickness ca. 100nm

→ Superior abrasion properties !


Abrasion test Reference

Sol gel

Bioresponsive coatings 

Smart dressings for burn wounds: the wound dressing releases antimicrobials when needed and signals an (upcoming) infection via dye release

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Stabilised nanocapsules containing "switched off" dye and antimicrobial

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Pathogenic bacteria release toxins and enzymes → opening of nanocapsules shell


Nanocapsules release signaling molecules and antimicrobials

Development of PV cells and batteries at fibre level


Summary 

(Coated) Textiles have a broad range of applications. Both for garments and for technical textiles Coating enables textile as “flexible functionality carrier”  

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The classical techniques dominate. Relatively simple, reliable, large scale 

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Continuous search for novel methods, materials and applications. Methods: energy consumption ↓, accuracy ↑ Materials: “bio-…”, “nano-…” Applications: electrical conductive, bioresponsive, …   


Coating Application in Textile

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