corona treatment &. plasma treatment - the opportunties
TRANSCRIPT
Presented by
Rory A. WolfBusiness Unit Manager Pillar Technologies
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Corona Treatment & Plasma Treatment
The Opportunities
Presentation Agenda
o Overview of Surface Treatment Systems
o What Corona Treatment Does to a Surface
o Understanding Dyne Levels
o Factors that affect Dyne Levels
o What does a Corona Treater do to a Surface?
o Corona-Generated Adhesion
o What does a Plasma Treater do to a Surface?
o Plasma-Generated Adhesion
o Optimizing Surface Treatment Generated Adhesion
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Overview of Surface Treatment Systems
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Polymer surfaces are continuously treated at a wide range of web speeds
Principle of Corona Treatment
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Bare Roll Covered Roll Dual Dielectric
Types of Corona Systems
Advantages No roll covering to fail Ceramic electrodes Treats conductive / non-conductive
materials All converting applications
Disadvantages Roll oxidation requires cleaning Requires large volumes of makeup air,
as air is needed to cool the electrodes.
Advantages Wide range of roll coverings, metal
electrode Designed to treat non-conductive
materials Easy to adjust treat width, and lane
treating with segmented electrodes
Disadvantages Organic roll coverings can have
short life Cannot treat conductive materials
Advantages Ceramic roll covering, ceramic
electrode Treats conductive / non-
conductive materials Higher treat levels Even distribution of discharge Increased roll surface capacitance. Nearly eliminates wrinkling,
pinholes, backside treat
Disadvantages None
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Understanding Dyne Levels
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Understanding Dyne Level
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Liquid/Polymer Total Surface Tension (mN/m)
Dispersive Component (mN/m)
Polar Component (mN//m)
Formamide 58.0 39.0 n/a
Di-iodomethane 50.8 50.8 0.0
Water 72.8 26.4 46.4
Polypropylene 30.1 30.1 0.0
Treated Polypropylene 42.0 30.0 12.0
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Factors that affect Dyne
Levels
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Factors that affect Dyne Levels
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Low molecular weight oxidized polymeric material following over-treatment of BOPP film
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Factors that affect Dyne Levels
Backside Treatment
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Factors that affect Dyne Levels
Surface Crystallinity
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Additive Migration MechanismOleamide, Erucamide, Stearamide
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What does a Corona treater do
to a surface?
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Corona Discharge
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Corona-Generated Adhesion
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Corona-Generated Adhesion
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The formation of polar functional groups and reactive species is the primary mechanism through which improved surface characteristics are imparted to films. Some of these species are:
* Peroxides and ozanides: R[O2]R, ROOH, R[O3]R
* Ions
* Neutral functional groups
* Ozone
* Film surface crosslinking
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Excited O2 molecules become unstable and decompose into radicals, ions and photons
Discharge creates initiating H, O, OH and N radicals, which in turn create ketone, aldehyde, ether, and carboxyl groups.
Surface etching and roughness created by micro-arcs.
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Pillar TechnologiesSurface Treatment
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What does a Plasma treater do
to a surface?
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Polymer Film
Glow Discharge Plasma Source(Discharge composed of molecules, atoms, ions)
Clean surface w/ dangling bonds
Film Processing Direction
Volatilized, vaporized
contaminants, water vapor,
CO, CO2, unreacted
process gases
Exhaust Stream
Volatilized, vaporized contaminants, water vapor, CO, CO2, unreacted process gases
Exhaust Stream
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What does a Plasma Treater do to a Surface
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Plasma-Generated Adhesion
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Plasma-Generated Adhesion Pillar TechnologiesSurface Treatment
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Plasma-Generated Adhesion Pillar TechnologiesSurface Treatment
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Depending on the material to be treated and the nature of the plasma gas, several mechanisms contribute to adhesion:
Plasma activation with plasma-forming gases, such as Argon, has a large mechanical effect, continuously removing single atoms out of the surface.
The remaining radical sites are highly reactive and promote the adhesion of inks, coating and adhesives.
With oxygen added to the plasma activation process, polymers receive new surface functionalities which completely reverse the polarity of materials such as polypropylene.
After plasma activation, aqueous solutions with high surface tension spread on the activated surface, showing very small contact angles.
On base metals, surface oxide layers form within minutes. Plasma activation with hydrogen-containing plasma gas reduces superficial oxide layers on which will free the clean, reactive metal surface for bonding.
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Optimizing Surface Treatment Generated
Adhesion
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Optimizing Surface Treatment Generated Adhesion
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Mechanical InterlockingAdsorption
Van der Waals Interactions/ElectrostaticDiffusion/Interdiffusion
Chemisorption
Adhesion
Cohesion
Adhesion
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Surface energy of a substrate, and particularly polymer substrates, can be increased by means of both chemical and physical treatments.
Surface treatments include: Cleaning of the surface by corona, flame or plasma treatments. Applying a chemical or coating primer to the surface.
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Optimizing Surface Treatment Generated Adhesion
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There must be molecular entanglement to promote strong adhesion.
Surface Treatment promoted wettability, and subsequently the potential for Entanglement
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No entanglement “Nail Adhesion” -little entanglement
Entanglement
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Treatment Recommendations
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Polymer TypeSurface free energy
(SFE) at 20 °C in mN/m
Dispersive contrib. of SFE in mN/m
Polar contrib. of SFE in mN/m
Polyethylene-linear PE 35.7 35.7 0
Polyethylene-branched PE 35.3 35.3 0
Polypropylene-isotactic PP 30.1 30.1 0
Polyisobutylene PIB 33.6 33.6 0
Polystyrene PS 40.7 -34.5 -6.1
Poly-a-methyl styrene PMS 39 -35 -4
Polyvinyl fluoride PVF 36.7 -31.2 -5.5
Polyvinylidene fluoride PVDF 30.3 -23.3 -7
Polytrifluoroethylene 23.9 19.8 4.1
PTFE 20 18.4 1.6
Polyvinylchloride PVC 41.5 -39.5 -2
Polyvinylidene chloride PVDC 45 -40.5 -4.5
Polychlorotrifluoroethylene PCTrFE 30.9 22.3 8.6
Polyvinylacetate PVA 36.5 25.1 11.4
PMAA 41 29.7 10.3
Polyethylacrylate PEA 37 30.7 6.3
Polymethylmethacrylate PMMA 41.1 29.6 11.5
Polyethylmethacrylate PEMA 35.9 26.9 9
Polybutylmethacrylate PBMA 31.2 26.2 5
Polyisobutylmethacrylate PIBMA 30.9 26.6 4.3
Poly(t-butylmethacrylate) PtBMA 30.4 26.7 3.7
Polyhexylmethacrylate PHMA 30 -27 -3
Polyethyleneoxide PEO 42.9 30.9 12
Polyethyleneterephthalate PET 44.6 -35.6 -9
Polyamide-6,6 PA-66 46.5 -32.5 -14
Polyamide-12 PA-12 40.7 35.9 4.9
Polydimethylsiloxane PDMS 19.8 19 0.8
Polycarbonate PC 34.2 27.7 6.5
Polyetheretherketone PEEK 42.1 36.2 5.9
Target treatment level will be predicated on:
1) SFE of the base substrate
2) SFE of the adherend (ink, coating, adhesive)
Treatment Recommendations
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Application Example:
Material: Cast PPExpected SFE (untreated): 30.1 mN/mRequested Treat Level: 46.0 mN/mProcess Line Speed: 200 fpm# of Sides Treatment 2 SidesSpecified Watt Density: 10 W/ft2/minElectrode Configuration: SS SegmentedRoll Configuration: Ceramic
Dielectric Constant
Dielectric Strength (v/Mil)
Ozone Resistance Cut Resistance Heat Dissipation
Hypalon 5 to 6 400 Good Poor FairEpoxy 3 to 4 450 Good Excellent FairSilicone 4 to 5 450 Good Poor Good-Exc.Bonded Silicone 3 to 5 450 Good Poor Good-Exc.Ceramic 8 to 10 500 Excellent Excellent ExcellentGlass 7 to 8 500 Excellent Excellent Excellent
Porosity Field Reparability
Max. Cont. Service Temp.
(F)Hardness (Shore A) Cost
Hypalon Excellent Fair 150-300 60-90 LowEpoxy Good Excellent 190-250 70-80 LowSilicone Excellent Fair 250 60-90 MediumBonded Silicone Excellent Fair 350 60-70 MediumCeramic Good Fair 350 (55 Rockwell C) Medium-HighGlass Excellent Poor 800 (50 Rockwell C) High
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Corona Treatment vs Plasma Treatment
Rory A. WolfBusiness Unit [email protected]