Coating Application in Textile

Coatings and their applications in textilesG. Buyle – MIICS 2012

G. Buyle - MIICS - 20120314

Textiles… various applications

G. Buyle - MIICS - 20120314

Outline

Introduction Centexbel

Basic textile coating Advanced coating techniques

Examples of applications

G. Buyle - MIICS - 20120314

Acknowledgements

Research at Centexbel on topic “smart textiles” enabled via several research projects

Acknowledgement of the funding agencies on different levels: 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. Buyle - MIICS - 20120314

Outline

Introduction Centexbel Basic textile coating Advanced coating techniques

Examples of applications

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Centexbel: centre of competence

collective research and technical centre

membership organisation Belgian textile companies associated (international) member companies and

organisations

staff 140 skilled and highly educated men and women

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Research groups

Three domains: 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,…

G. Buyle - MIICS - 20120314

textile functionalisation and surface modification

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 :

E.g. breathability, outdoor ageing

Chemical : E.g. chemical analysis, microscopy

Microbiological : E.g. antimicrobial effect, biodegradability

Fire : E.g. burning behaviour, smoke toxicity

Centexbel is recognized by large distribution companies, consumers’ associations, OEM’s, …

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(pre-)standardisation

Active participation/leading role in standardisation committees (CEN & ISO)

Sector operator Mirror committees Centexbel leads

WG31 “Smart Textiles”(in CEN TC248)

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Outline

Introduction Centexbel

Basic textile coating Advanced coating techniques

Examples of applications

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Vision: textile as flexible carrier foroffering specific functionalisation(s)

Fire Retardant

Breathable

Electrically conductive

Biocompatible

Antibacterial

Self cleaning

Anti abrasion

Light Reflection

Thermal insulation

Water repellencyFragrance release

Bioresponsive

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Three levels of coating fabrics

Fabriclevel

Yarnlevel

Filament/fibrelevel

Traditional coating

“Advanced”techniques e.g. plasma

coating

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Materials

Textile coating typically comprises 2 parts: Binder for durability

(washing, abrasion) Additives for functionality

Materials for binder: Polyacrylate Polyurethane Polyvinylchloride

Example nanoparticles for textile coating

NP

Matrix/binder

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Example: lamination of membrane in-between two textile fabrics

Membrane

Knitted fabric

Woven fabric

Coating

Coating

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Example: Fire Retardant coating for carpet

Coating application

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Carpet coating analysis via XRF mapping

Ti

Br

Sb

S

Carpet structure FR additives

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Example: PVC coated polyester fabric

Textile architecture Tarpaulins for trucks

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Classical techniques:

Wet techniques: Formulation: solvent or water based Application unit: padding/ immersion,

knife coating, transfer coating, foam coating,…

Typical add-on: 20-50g/m2

Multitude of advantages: Robust Large scale Relatively simple equipment

Immersion

Mayer bar

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Classical techniques: typical coating line

Wet technique → need for ovens → energy issue

“Long” → only profitable for large batches

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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: 100% system

(granulates, blocks,…) Melting of the polymer Application as melt Solidifying → Coating Materials: PE, PP, PES, PA,

EVA, TPU, silicone

Two main groups (curing based): Thermoplastic hot melts:

Solidifying via cooling Reactive hot melts:

Solidifying via cooling + drying or UV irradiation

Source: www.robatech.com

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UV curable coatings

UV

IR

Coating application

IR sourceUV source

Curing

Textile substrate

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Polyolefine-coatings (1/2) POD = po lyolefine dispersion in water, suitable

for “standard” application techniques

Source: Dow

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Polyolefine-coatings (2/2)

PODs have unique advantages: Solvent-free solution High solid content (typically 40 to 55 wt%) Functionalisation possible

Functionalisation: Possible to mix in active components Examples: FR, antimicrobial, conductive

Goal: replace some of the PVC applications (prevention of phthalates)

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Outline

Introduction Centexbel

Basic textile coating

Advanced coating techniques Examples of applications

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Advanced coating techniques

ALD Evaporation Magnetron sputtering

Atmospheric Plasma coating

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Deposition via ALD: Atomic Layer Deposition Process at low pressures

(in vacuum chamber)

→ highly conformal coatings

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

Source: Hyde et al.

ALD technique - introduction

ALD technique

Standard technique

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ALD deposition into non woven substrate

Outside

Inside

Deposition is uniform throughout the sample

Example*: ALD deposition on non woven (NW): Al-oxide (Al2O3) deposition PES NW cube dimensions: side = 3.5cm XPS analysis: penetration of coating ?

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

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Advanced coating techniques

ALD

Evaporation Magnetron sputtering

Atmospheric Plasma coating

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Evaporation for textiles

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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Advanced coating techniques

ALD

Evaporation

Magnetron sputtering Atmospheric Plasma coating

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Magnetron sputtering on textile

Bron: Tersuisse Multifils

Commercially available: silvercoated PA monofilament

Use: Textile electrodes Antimicrobial textile

But… cost factor !!!

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“Most Luxurious Necktie Ever ? ...”

Gold coated silk

Source: www.ecouterre.com

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

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Advanced coating techniques

ALD

Evaporation Magnetron sputtering

Atmospheric Plasma coating

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Atmospheric plasma coating

Plasma source

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

Precursor

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Atmospheric plasma coating equipment*

Key properties: For wide substrates (up to 40 cm) Corona + possibility to add liquid precursor

* Available through cooperation with Univ. College Ghent

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Example: surface analysisantimicrobial coating

XPS and ToF-SIMS → chemical composition

Untreated Uniformly treated“Badly” treated

Size = 5x5mm2, color = specific for chemical group, PES fabric

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Outline

Introduction Centexbel

Basic textile coating Advanced coating techniques

Examples of applications

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Electrical conductivity: integration of carbon nanotubes in textile coatings

0

100020003000

4000

50006000

70008000

0 2 4 6 8 10wt % CNT

Res

istiv

ity (O

hm)

Acrylic based coating with increasing CNT content: Highly flexible textile coatings Conductivity starts at 4 wt% CNT, resistivity down to 60 Ω (!)

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SEM pictures: coated fibre with well distributed CNT network

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Application: Integration of solar cells in textile 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

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Application: conductive yarn via CNT, used in antistatic fabrics

Patent pending(EP2011002735)

Antistatic fabric

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Self Healing properties

Several principles exist for reaching self-healing (mixing of substances when crack/scratch appears)

Own development for textile:Freshly scratched After self-healing

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Abrasion resistance via sol-gel chemistry for textiles

Characteristics: 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

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Bioresponsive coatings Smart dressings for burn wounds: the wound dressing

releases antimicrobials when needed and signals an (upcoming) infection via dye release

Stabilised nanocapsules containing "switched off"

dye and antimicrobial

Pathogenic bacteria release toxins and

enzymes → opening of nanocapsules shell

Nanocapsules release signaling molecules and antimicrobials

1. 2. 3.

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Development of PV cells and batteries at fibre level

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Summary

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

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

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

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Contact

Contact info:

Guy Buyle

CentexbelTechnologiepark 7

9052 ZwijnaardeBELGIUM

www.centexbel.be

Tel: +32 9 220 41 51Fax: +32 9 220 49 55

Guy.Buyle@centexbel.be