1

Coating Plasma Innovation

CONFIDENTIAL

Optimization of atmospheric plasma

for high speed industrial applications

2

Plasma

Cold atmospheric plasma

Plasma, Jet, Corona

CPI Optimizations

Conclusions

3

Plasma

4th state of matter: ionized gas

4

Cold atmospheric plasma

Energetic electrons chemistry

Cold:Tgas < 100 °CTions,neutrals < 100 °C Telectrons ≈ 10 000 °C

Atmospheric:Plasma gas is at atmospheric pressure Open reactor, high density of particles

Hot:Tgas ≈ Tions,neutrals ≈ Telectrons

104

5

Corona

High Voltage

Ambient airFilamentary discharge

• Used for activation or cleaning• Flat substrate• Most of the time need to be used

inline with other process• Gas used: none (ambient air)

6

Plasma jet (blown arc)

Max

. a f

ew c

m

Post

-dis

char

ge

Gas injection (plasma gas + reactive gas or precursor)

Precursor

• Used for activation or cleaning, deposition possible

• 3D substrate• Gas used: Air, N2, Ar, He• Gas consumption: 30 -60 l/min (

10L/m² @ 100 m/min)

Controlled atmosphere

Uncontrolled/partially controlled atmosphere

7

Plasma DBD

High Voltage

Gas injection (plasma gas + reactive gas or precursor)

Controlled atmosphereHomogeneous discharge

• Used for activation or cleaning, deposition possible

• Flat substrate• Used online or offline• Gas used:N2, (Ar, He)• Gas consumption (CPI tech) < 5L/m²

(50 – 500 m/min)

PlasmaCorona

8

Plasma vs Corona

Very large web width Common technology

CostCleaning

ActivationGraftingCoating

Uncontrolled atmosphereAggressive chemistry

Limited range of materialsInhomogeneous treatment

Pin holesBackside treatment

Low efficiencyTemporary effect

Large web width Controlled atmosphereHomogenous treatment

No surface damageNo backside treatment

High performance treatmentLong lasting effect

CleaningActivationGraftingCoating

Wide material rangeCommon technology

Cost

9

Plasma vs Corona

Microscopy (AFM) image of BOPP film1 µm x 1 µm images (Tapping)

Identical discharge power

Es = 38 mN/mEs ≤ 30 mN/m Es = 60 mN/m

Untreated Plasma

DBD Corona

Controlled chemistry, homogenous discharge no surface damage

10

Plasma vs Corona

Controlled chemistry Long lasting treatment, higher surface energy

Surface energy measurements on BOPP film

DBDTorch/Jet

11

DBD vs Jet/torch

• Localized treatment (max width ≈10 cm)• Indirect plasma exposure (post discharge)• Medium speed treatment (10’s

m/min)• 3D and complexes shape substrate• Partially controlled atmosphere• Cleaning, Activation, Grafting, Coating

• Up to several meters web width• Direct plasma exposure• High speed treatment (100’s of

m/min)• Thin flat substrate• Controlled atmosphere• Cleaning, Activation, Grafting,

Coating

12

Cleaning - Grafting - Coating

Cleaned sample

CO2↗, H2O ↗ …

Contaminated surface

Plasma

Surface contamination

Torch, Corona, Plasma

13

Cleaning - Grafting - Coating

C

O

C

O

C

O

C

O

H

CC

O

C

OO

C

O

C

O

H

C CC CC C

O

Amine AmideImide

N

C

H H

C

2O

C

NH

C

O

C

ON

C

H

C

Gas N2 + dopants

0

1

2

3

4

5

Amine Amide Imide

Qu

an

tity

(a.u

.)

Grafting of nitrogen containing groups

Standard

Advanced 1

Advanced 2

% A

tom

iqu

e (X

PS)

Dopant 1Dopant 2

Torch, Corona, Plasma

14

Cleaning - Grafting - CoatingSpecific molecules (precursor ) are added to the plasma gas. Those molecules are activated ( ) by the plasma and react with the sample surface to form a thin film.

HMDSO precursor

Torch, Corona, Plasma

SiOx hydrophilic

SiCyOx hydrophobic

15

Conclusions

Corona is adapted for basic treatment of low value materialsLimited performance regarding surface energy, durability of treatment and range of materials treatable

Plasma jet are adapted to localized treatment and 3D shaped objectsCost and technical issues for large scale treatment

Plasma DBD is adapted to high performance applications and/or high performance materials. Not competitive if corona can achieve the same goal

16

C O A T I N G P L A S M A I N D U S T R I E

Plasma

Cold atmospheric plasma

Plasma, Jet, Corona

CPI Optimizations

Conclusions

17

Needed Improvement in atmospheric plasma technology

1st generation of atmospheric plasma issues:

Treatment speed was too slow Gas consumption was too high Some materials could not be treated Coating was difficult

Cost was too high in regard of the performances

18

Improvements in electrode design• Homogenous plasma at high power density• Longer exposure time with similar footprint

Improvements in gas dynamics:• Controlled Chemistry even at high web speed• Reduction in gas consumption

High power density, longer exposure time: High speed treatment Inert material treatment such as fluorinated polymers

Homogenous discharge, controlled chemistry: No hot spots, no damage of films (LMWOF) Stable atmosphere allow to add controlled amount of dopant gas (vapors) Treatment of sensitive or difficult materials (PTFE, ECTFE, PEEK, PLA…)

Optimizations

19

Dosage

The plasma dosage (d) represents the amount of electrical energy applied the material during the treatment

𝑑 =𝑃𝑙𝑎𝑠𝑚𝑎 𝑝𝑜𝑤𝑒𝑟

𝑊𝑒𝑏 𝑤𝑖𝑑ℎ𝑡 × 𝑊𝑒𝑏 𝑠𝑝𝑒𝑒𝑑=

𝑊

𝑚 ×𝑚𝑚𝑖𝑛

=𝑊 ⋅ 𝑚𝑖𝑛

𝑚²

0

20

40

60

80

100

120

0,0E+00

2,0E+04

4,0E+04

6,0E+04

8,0E+04

1,0E+05

1,2E+05

0 200 400 600 800 1000 1200

Do

sage

[W

min

/m²]

P c

st=5

00

0W

Pow

er [

W]

dcs

t=1

00

W

min

/m²

Web Speed [m/min]

Power

Dosage

Constant Power

Constant Dosage

20

Electrode design

High power density High Dosage at high speed

21

Electrode design

High Dosage without damage Long lasting treatment

Corona limit

22

Controlled atmosphere - dopant

Dopant same performance at lower dosage

N2 Dopant 1

N2 Dopant 2

N2 Dopant 3

23

Gas dynamics

At high speed the film carries an air boundary layer in the plasma zone

Film800 m/min

High Voltage

Air (Oxygen) is introduced in the plasmaChemistry of the plasma is not controlled

O2

con

cen

trat

ion

[a.

u.]

N2

Air boundary layer must be removed:• High N2 flow rate• Optimized gas diffusor geometry• Low power corona• Physical barrier• …

PlasmaZone

24

Gas dynamics - Controlled atmosphere

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600

O2

con

cen

trat

ion

[p

pm

]

Web Speed [m/min]

5 m3/h

10 m3/h

15 m3/h

20 m3/h

30 m3/h

40 m3/h

50 m3/h

High O2 concentration

25

Electrode-gas diffusor assembly optimization running cost ↘↘

Gas dynamics - Controlled atmosphere

1 2

0

5

10

15

20

25

30

0 100 200 300 400 500 600

N2

[l/m

²]

Web Speed [m/min]

N2 consumption per m² of treated material

Optimized

Classical

3

26

Controlled atmosphere

0

1

2

3

4

5

6

30

35

40

45

50

55

60

65

70

0 50 100 150 200 250

% o

f g

raft

ed n

itro

gen

Su

rface

En

erg

y (

mN

/m)

Nitrogen flow rate (l/min)

Nitrogen grafting on BOPP (50m/min)

O2 ≥ 2000 ppm

O2 ≥ 2000 ppm

O2 < 20 ppm

Good inerting Higher surface energy

Plasma

Corona

27

Thin film Coating

Coating by atmospheric plasma pressure was/is hindered by: Powder formation in the gas phase

low adherence to substrate low quality powdery film

Powder formation on the electrode high maintenance

Optimized electrode gas diffusor assembly solves those issues

Remaining issue: high density film at high speed Dense film at 10th m/min slow for industrial use Deposition at 100th m/min low density film

28

Conclusions

Improvements in electrode design and gas dynamics allowed to overcome most of the previous atmospheric plasma limitations.• Treatment speed are very high (hundreds of m/min)• Running cost are becoming competitive• Chemistry of the plasma can be controlled

Plasma is adapted to high performance materials and/or high performance applications

29

Thank you