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Improving Improving Flexographic Ink & Flexographic Ink & Coating Adhesion Coating Adhesion Rory A. Wolf Rory A. Wolf VP Business Development VP Business Development Enercon Industries Corporation Enercon Industries Corporation Enercon Industries Corporation Enercon Industries Corporation

Improving Flexographic Ink & Coating Adhesion

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By Rory A. Wolf, Enercon Industries Corporation This excellent technical presentation addresses: Surface Adhesion Challenges Corona Technologies Flame Technologies Plasma Technologies

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Page 1: Improving Flexographic Ink & Coating Adhesion

ImprovingImprovingFlexographic Ink & Flexographic Ink & Coating AdhesionCoating Adhesion

Rory A. Wolf Rory A. Wolf

VP Business DevelopmentVP Business Development

Enercon Industries CorporationEnercon Industries Corporation

Enercon Industries CorporationEnercon Industries Corporation

Page 2: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Flexo Industry Challenges

Higher Productivity & Efficiencies Higher press speeds Minimal press setup Fully automatic changeover of plate cylinder

mandrels/sleeves, anilox rollers/sleeves Next job make-ready organization Self-adhesive plate sleeves

Page 3: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Surface Adhesion Challenges

Water-based interfaces are formulated with non-soluble binders composed of styrene acrylic alkali-soluble binder and resin emulsion.

Page 4: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Surface Adhesion Challenges

Substrate

As interfaces dry, ammonia and volatile amines leave and emulsion particles can “touch,” combining to form a surface film.

Page 5: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Surface Adhesion Challenges

Substrate

Trapping these interfaces can trap volatile amines which can exist as salts, interfering with interface-to substrate and interface-to-interface bonding.

Page 6: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Surface Adhesion Challenges

Tribocharging caused by contact and separation of a web from rolls can cause “spidering” of flexo inks and coatings following impression to the web.

Tribocharging effect influences surface tension requirements

Page 7: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Surface Adhesion Challenges

2x2 micron images of PET film

•No Corona Treatment

•WD = 1.16W/ft2/min (12.5W/m2/min)

•WD = 1.93W/ft2/min (20.8W/m2/min)

•WD = 2.71W/ft2/min (29.2W/m2/min)

Topographical Image Phase Image (Height – 10nm) (Range – 60º)

Page 8: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Surface Adhesion Challenges

Slow Speed High Speed

Treater Ground Roll

Treater Ground Roll

Contact Area

Contact Area

…………………………………….. ……………………………………..

Boundary Air Boundary Air

Contamination Contamination

Boundary layer air and surface contaminations reduce ground roll contact area at high speed with current art surface activation systems

Reduction in complete surface activation by entrained air behind the web, causing backside treatment.

Page 9: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Profile of a Corona Discharge Profile of a Corona Discharge

A corona discharge is a high-voltage arc in air. When air is ionized, the electrons collide with the material surface to break the molecular bonds, creating free radicals that react in the presence of oxygen to form high-polarity functional groups.

Page 10: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies Bare Roll

Page 11: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Page 12: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Benefits of Bare Roll Can treat any substrate

including metallized films and foils

Safe No roll covering to fail Open station design

Drawbacks On difficult to treat

materials, may require a higher watt density

Unable to lane treat

Page 13: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Covered Roll

Page 14: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Benefits of Covered Roll Economical (depending

on roll covering) Can treat most polymers Can vary treat width Used primarily in film

extrusion

Drawbacks Roll coverings can fail

easily Cannot treat metallized

films and foils

Page 15: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Page 16: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Universal Roll (High Definition)

Page 17: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Page 18: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Corona Technologies Overview of Corona Technologies

Benefits of Universal Roll Can treat any substrate

including metallized films and foils

Safe Open station design

Drawbacks On difficult to treat

materials, may require a higher watt density

Unable to lane treat

Page 19: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Corona Discharge SafetyCorona Discharge SafetyThe standard Safety interlocks provided with Enercon surface treaters are:

Zero Speed Interlock Electrode Position Interlock Exhaust Air Flow Interlock.

Other optional interlocks may include:

Differential Pressure Interlock for purged systems, Access Door Interlocks Trip Cable Interlocks E-Stop Interlocks.

Each of these interlocks are connected in series. If just one of the interlocks is open, the power supply will not be allowed to enter the RUN mode when the start command is received.

Page 20: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Flame TechnologiesOverview of Flame TechnologiesRibbon Burners Cast Iron Body Stainless Steel Ribbon Ports Water Cooled with Continuous

Tubes on sides of Ribbon Stacks

Drilled Port Burners Aluminum Body CNC-drilled Ports in Brass insert Water Cooled with Lateral Ports

between Burner Sections.

Page 21: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Flame TechnologiesOverview of Flame Technologies Flame DetectionFlame Detection Off-Set of Flame TemperatureOff-Set of Flame Temperature Line Speed below the Set PointLine Speed below the Set Point Max or Min Gas PressureMax or Min Gas Pressure Min Air PressureMin Air Pressure Web BreakWeb Break EmergencyEmergency Flash Back ControlFlash Back Control Incorrect Distance (Gap) between Flame and SurfaceIncorrect Distance (Gap) between Flame and Surface Timer for IgnitionTimer for Ignition Gas Leakage ControlGas Leakage Control

Control ResponseControl Response Cut-Off Gas FlowCut-Off Gas Flow Sound and Flash AlarmSound and Flash Alarm

Page 22: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Plasma TechnologiesOverview of Plasma Technologies

Plasma Glow Discharge

Page 23: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Overview of Plasma TechnologiesOverview of Plasma Technologies

Plasma Activation Changes free radicals on the surface by substituting chemical

groups on the polymer chain being modified.

Plasma Deposition Hydroxyl, carbonyl, carboxyl, carboxylic,

amino-carboxyl, and amine chemical groups on surface

Plasma-Induced Grafting Free radicals are created along the

polymer backbone.

Page 24: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Surface Treatment LongevitySurface Treatment Longevity

Page 25: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Recommended Treatment Parameters by ProcessRecommended Treatment Parameters by Process

Recommended Process Parameters - WD1 / Tension2

Corona Flame3 Atmospheric Plasma

OPP, BOPP (flexo ink adhesion) 27.8-33.3 / 42 - 48 277.8 / 44 22.2-27.8 / 42 - 48

PET, BOPET (flexo ink adhesion) 13.8-19.4 / 50 -56 148.2 / 52 8.8 - 11.1 / 50 - 56

PE (flexo ink adhesion) 27.8-33.3 / 42 - 48 277.8 / 44 22.2-27.8 / 42 - 48

SiOx-coated PET (flexo ink adhesion) 88.9 - 111 / 38 - 44 Data limited 66.6 - 88.9 / 38 - 44

Metallized Films (flexo ink adhesion) 33.3-55.6 / 42 - 46 Data limited 22.2 - 44.4 / 42 - 46

Aluminium Foil (flexo ink adhesion) 36.6 - 54.5 / 60 - 70 Data limited 22.2 - 44.4 / 60 - 70

Coated Paper, Paperboard (flexo ink adhesion) 16.6 - 22.2 / 42 - 44 222.2 / 43 11.1 - 16.7 / 42 - 44

Extruded LDPE Coating (adhesion to paper/paperboard) 16.6 - 22.2 277.8 11.1 - 16.7

Note: 100% Ink coverage assumed for polymer melt adhesions over inks.

1 Watts/m2/min. range

2 Dynes/cm range

3 1kW = 3,412 BTUs/hr./lineal burner inch (Enercon PowerFlame burner), 11:1 stoichiometric ratio. Dyne data is minimum outcome.

4 Assumes extrudate melt temperature of 300-320C.

Page 26: Improving Flexographic Ink & Coating Adhesion

Enercon Industries CorporationEnercon Industries Corporation

Author Contact InformationAuthor Contact Information

Rory A. Wolf

VP Business DevelopmentVP Business Development

Enercon Industries [email protected]