june 17-18, 2013 – columbus, oh. question: “is there a way to improve adhesion of two-component...

Dry, Chemical-Free Surface Treatment for

Powder Coated Substrates

June 17-18, 2013 – Columbus, OH

Question:“Is there a way to improve adhesion

of two-component polyurethane adhesivesto polyester- and epoxy-based

powder–coated surfaces?”

PC Summit, 2013

Source: Products Finishing Magazine, Powder Coating Clinic, April 2013

Answer:“It is possible to apply an adhesive over a powder.

The challenge is to find an adhesive/powdercombination that works. You need to select a powder

that meets the performance and appearanceproperties you need, and then work with an adhesive

supplier to find the correct adhesive…”

PC Summit, 2013

Source: Products Finishing Magazine, Powder Coating Clinic, April 2013

Answer:“…Polyester powder is more likely to provide adhesion

than epoxy powder. You can roughen the surfacewhere you need the adhesion,but that may not be feasible.Talk to an adhesive supplier

and you should be able to make it work.”

PC Summit, 2013

Source: Products Finishing Magazine, Powder Coating Clinic, April 2013

Problem StatementPowder coated materials present

downstream bonding issues.

Potential Applications• adhesive bonding• label application

• decoration (pad printing, silk screening)• foam gaskets

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Fundamentals of Paint Adhesion The molecules in the paint film wet or flow

freely over the substrate Chemical bonds are formed at the interface The paint film penetrates the roughness on the substrate surface, resulting in mechanical

interlocking once the paint dries.

PC Summit, 2013

Source: www.metalfinishing.com, Fundamentals of Paint Adhesion, Ed Petrie

Surface Wetting

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Surface Energy Measurement

Low Surface Energy High Surface Energy

PC Summit, 2013

PC Summit, 2013

Contamination

Anti-oxidants

Cross-linkers

Fillers

UV Modifiers

Pigments

Slip Agents, Waxes

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Wet

Che

mic

al CleanerSolventPrimer

Mec

hani

cal

ScuffSandBlast

Phys

ical

FlameCoronaPlasma

Surface Modification Options

Is There a Perfect Solution?

PC Summit, 2013

• Reliable• Repeatable• Easy to useRobust Process

• In-Line• Easy to automate• Easy to integrateLabor Reduction

• No chemicals• No ozone• No wasteSafe

• Material savings• Labor savings• Reduced liabilityCost Effective

Plasma: The 4th State of Matter

Solid Liquid Gas

+

+

**

e-

e-

e-

**

gas molecule

*gas molecule(excited)

*

ionsfree electron

+e-

–

+–

–

+

+

Plasma

moleculefragment (high-energy)

Plasma

PC Summit, 2013

Flame Treatment Low ion density Activation only- little or no cleaning Thermal distortion Inconsistent-ambient conditions Contamination Liability – open flame High consumable cost Metals/mixed materials not possible

PC Summit, 2013

Corona Discharge Better ion density Activation only- little or no cleaning Tight application tolerances Liability - ozone High voltage at interface Metals/mixed materials not possible

PC Summit, 2013

Vacuum Plasma High ion density Cleaning & activation Complex chemistries possible Offline process Not selective

PC Summit, 2013

Openair™ Plasma High ion density Cleaning & activation Simple inputs – power/air In-line process Selective treatment Low/no voltage No ozone $0.10 to $0.25/hour

PC Summit, 2013

PC Summit, 2013

Source: Guideline to Bonding Plastics, ANTEC-2013Michael Oliveira, Henkel

Openair™ Plasma Jet

Substrate

Inner Electrode

Ionization GasHigh voltage Current

Plasma

Ring Electrode (SS casing)

Discharge Chamber

PC Summit, 2013

Attack Surface Contamination

C

O

O

N*

* *

*N N

O

N

N

N

ON

O

O

N

O

*

*

*

C C C C C C C

HHHHHHH

H H H H H H H

PC Summit, 2013

Remove Surface Contamination

C

C C C C C C C

HHHHHHH

H H H H H H H

O

O

N*

* *

*N N

O

N

N

N

ON

O

O

N

O

*

*

*

PC Summit, 2013

C O

N

C C C C C C C

HHHHH

H

H

H

H

H

H

H H H

OO

O

O

O

O N

N

N

N

NN

N

*

**

*

*

**

Form Functional Sites

PC Summit, 2013

Straight Jet

Focused plasma cleaning & activation Long term stability Low consumable parts Flexible with different nozzles Speed: up to 70m/min Gap: 5 to 20 mm 15 mm max treatment width

PC Summit, 2013

Rotational Jet

Wide area plasma cleaning & activationLong term stabilityLow consumable partsFlexible with different nozzlesSpeed: up to 35m/minGap: 5 to 20 mm50 mm max treatment width

PC Summit, 2013

Openair™-Plasma Jet Heads – Rotating Jet

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Continuous MonitoringIf you can’t see the treatment, how do you know it’s there?

PC Summit, 2013

• Voltage• Amperage• Air Flow• Air Pressure• Pulse Frequency• Duty Cycle• Jet Rotation (if required)

Control the Inputs

Reliable, repeatable, fastNo dilution effect, steady stateNo expensive consumablesSurface cleaning of the complete structure of the

materialIn-line integration = small footprintEconomical and environmentally friendlyNo change in bulk properties of substrate

Advantages of Openair™ PlasmaCleaning & Activation

PC Summit, 2013

Powder Coating on Plastic!

PC Summit, 2013

What’s Next?

•Plasma Cleaning & Activation

•Conductive Agent

•Powder Application

•Heat (IR or Convection)

•UV Cure

Q & A/Discussion

PC Summit, 2013

jeff.leighty@plasmatreat.com847.783.0622 Ext. 2121