invisible but functional - antistatic coatings

12 mai 2023

Invisible but FunctionalAnti-static coatings

Smart Coating Application Lab

© sirris | www.sirris.be | [email protected] |

2 mai 2023 2© sirris | www.sirris.be | [email protected] |

Events due to Electrostatic (Dis)charging

Foto’s


Electrostatic generation and discharge


Anti-static properties Conductive plastics

Blend in conductive fillers

Can reduce mechanical strenght Change color Make processing more difficult

Coatings


Creating anti-static coatings

Carbon nanotubes (CNT) Increased strenght Flexible Transparent Permanent Moderate/high cost

Ref:Eikos

Ref: BYK Ref: BYK


Creating anti-static coatings ITO (Indium Tin Oxide)

Durable Non humidity dependent Transparent Permanent Vacuum technology or wet-chemical High cost

Ref: Evonik

Ref:Evaporated Coatings

Ref: Evonik



ATO (Antimony Tin Oxide) Durable Non humidity dependent Transparent Permanent Lower cost than ITO

Ref:Kriya Materials

Coated tubeUncoated tube



PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate)

Flexible Transparent Permanent/UV-degradation Water-based Low cost

Ref:AgfaRef: Heraeus

https://en.wikipedia.org/wiki/Poly(3,4-ethylenedioxythiophene)

https://en.wikipedia.org/wiki/Polystyrene_sulfonate






Sprays Easy to apply Based on anti-static chemicals (e.g. glycerol ester, alkyl

sulphonate) Attracting moisture from air

Non-permanent Low cost


Case: Playfields for electronic games

Belgian producer of electronic games

In house production and development (software, electronics, mechanics)



ESD problem Metal rolling ball on non-conductive

playfield ESD when ball falls thru hole, damaging

ledlight electronics



ESD problem Metal rolling ball on non-conductive playfield ESD when ball falls thru hole, damaging ledlight electronics

• Transparent wear-resistant 2-component varnish

• Non-conductive substrate and coating stack• Company trials with antistatic spray (sticky) and

conductive powders (loss of transparency) in varnish were unsuccessful



Request for coating with following properties Anti-static Transparent No decrease in existing wear-resistance Matt appearance No roughness increase (effect on ball speed)

Coating selection performed ATO (Antimoon Tin Oxide) based (lower cost than ITO) UV curable Transparent hardcoat



Results Optimizing application by spray coating Adapting coating solution for optimal spraying 5 minutes at 80°C , UV curing

Optimization of thicknessAdhesion (cross-cut)


Case: Playfields for electronic games Results

Gloss measurement angle 60° Qualificatio

nAs-is varnish 11 mattThick coating 91 High gloss

Optimized coating 22 Matt (silk gloss)

Roughness profile Ra (µm)

As-is varnish 0,67

Optimized coating 0,46



Wear-resistanceSample Roughness profile

# strok

es

As-is varnish 1500

Optimized coating 1500



Charge analysis

Charge analysis Without earthing Earthing

Charge Discharge Charge DischargeAs-is varnish 1-5kV Ionizing air above plate 1-5 kV Ionizing air above plate

Optimized coating 1-5kV Ionizing air above plate Not possible --

Alternative coating 1-5kV Ionizing air above plate 1-5kV Slow discharge

Alternative coating

Optimized coating

uncoated



Request for coating with following properties

Anti-static achieved Transparent achieved No decrease in existing wear-resistance improved Matt appearance achieved No roughness increase (effect on ball speed) achieved


Conclusions

Electrostatic problems will remain an important issue Increasing miniaturization and use of electronics in products

Broad range of permanent coatings that give your product anti-static properties or ESD protection Most of these coatings tunable in a broad resistivity range Thoroughly coating optimization necessary when adding dispersions

Combination with other properties are emerging Increasing added product value

2 mai 2023© sirris | www.sirris.be | [email protected] |

0498919463

[email protected]

Patrick Cosemans

Optional LinkedIn ProfilePatrick cosemans

2 mai 2023© sirris | www.sirris.be | [email protected] |

http://www.sirris.be

#sirris

http://www.linkedin.com/company/sirris

http://techniline.sirris.be

invisible but functional - antistatic coatings

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