Trends in Surface Treatment for Multi-Layer PackagingTrends & Challenges – Multi-Film Structures...

Trends in Surface Treatment for Multi-Layer Packaging

Presented by

Senthil Kumar

C.O.O.| Enercon Asia Pacific

Trends in Surface Treatment for Multi-Layer Packaging

Presented by

Senthil Kumar

C.O.O.| Enercon Asia Pacific

Major Presentation TopicsMajor Presentation Topics

Trends and Challenges – Multi-Film StructuresWet vs. Dry Trapping on Inks, Coatings & Adhesives Chemistry Effects on Interlayer AdhesionExperimental using Atmospheric Plasma Technology Results & Discussion Conclusions

Trends and Challenges – Multi-Film StructuresWet vs. Dry Trapping on Inks, Coatings & Adhesives Chemistry Effects on Interlayer AdhesionExperimental using Atmospheric Plasma Technology Results & Discussion Conclusions

Trends & Challenges –Multi-Film StructuresTrends & Challenges –Multi-Film Structures

Require structures which are:ClearGreat barrier performanceCan be used for retort to extend shelf life

Technology enabling:Bio-films w/ ethylene copolymer tie layers for sustainabilityMore layers, including micro- and nano-layersMust ensure no “misfit” with adhesive layers to avoid structural destabilization, decreasing interfacial adhesion

Require structures which are:ClearGreat barrier performanceCan be used for retort to extend shelf life

Technology enabling:Bio-films w/ ethylene copolymer tie layers for sustainabilityMore layers, including micro- and nano-layersMust ensure no “misfit” with adhesive layers to avoid structural destabilization, decreasing interfacial adhesion

Trends & Challenges –Multi-Film StructuresTrends & Challenges –Multi-Film Structures

As consumer marketplace expands globally, surface pretreatment requirements challenged:

New material combinationsMore 9-10 layer tear-resistant constructions requiredNano-multilayer films requiring increased printability, scuff resistance, high transparency , security. Flexible packaging converter trend toward higher-speeds, and away from inks which emit VOCs toward W/B and UV/EB curables.

As consumer marketplace expands globally, surface pretreatment requirements challenged:

New material combinationsMore 9-10 layer tear-resistant constructions requiredNano-multilayer films requiring increased printability, scuff resistance, high transparency , security. Flexible packaging converter trend toward higher-speeds, and away from inks which emit VOCs toward W/B and UV/EB curables.

PropositionsPropositions

Polymer film surface modification techniques improve acceptance of interfaces.

These techniques increase hydrophilic characteristics and surface –free energy.

Interlayer adhesion can be improved by applying high density, homogeneous surface modification techniques

Polymer film surface modification techniques improve acceptance of interfaces.

These techniques increase hydrophilic characteristics and surface –free energy.

Interlayer adhesion can be improved by applying high density, homogeneous surface modification techniques

PropositionsPropositions

Atmospheric plasma surface modification discharges are high density, non-filamentary, uniform, create hydrophilicity.

Study examines experimental data relating correlations between surface modification and interfacial adhesion effects.

Atmospheric plasma surface modification discharges are high density, non-filamentary, uniform, create hydrophilicity.

Study examines experimental data relating correlations between surface modification and interfacial adhesion effects.

Surface Modification PrerequisitesSurface Modification Prerequisites

Adhesion strength of inks, coatings, adhesives to polymers is relative to surfaces which are cleaned, micro-roughened, polarized and made hydrophilic.

Accomplished commercially by Web corona discharge (air plasma), flame plasma, variable chemistry plasma techniques

Adhesion strength of inks, coatings, adhesives to polymers is relative to surfaces which are cleaned, micro-roughened, polarized and made hydrophilic.

Accomplished commercially by Web corona discharge (air plasma), flame plasma, variable chemistry plasma techniques

Web Corona Surface Activation SystemsWeb Corona Surface Activation Systems

Web Flame Surface Activation SystemsWeb Flame Surface Activation Systems

Web Variable Chemistry Surface Activation SystemsWeb Variable Chemistry Surface Activation Systems

Measuring SuccessMeasuring Success

Peel AdhesionLap SheerTensile TestsFatigue/Tear Tests

Peel AdhesionLap SheerTensile TestsFatigue/Tear Tests

Wet vs. Dry Trapping on Inks, Coatings & Adhesives Wet vs. Dry Trapping on Inks, Coatings & Adhesives

Multiple interfacial layer adhesion sub-optimized.Rely on formulation chemistries for wet-to-wet, wet-to-dry adhesion, for in-line and off-line processes.Example 1: dry-trapping 2nd pass through printer, solvent-based interfaces can flake off due to wax content at surface layer.Example 2: “chalking” effect due to insufficient pigment binder for substrate adhesion.Example 3: binding-solvents and -oils drain through porous substrates, increasing delamination potential.

Multiple interfacial layer adhesion sub-optimized.Rely on formulation chemistries for wet-to-wet, wet-to-dry adhesion, for in-line and off-line processes.Example 1: dry-trapping 2nd pass through printer, solvent-based interfaces can flake off due to wax content at surface layer.Example 2: “chalking” effect due to insufficient pigment binder for substrate adhesion.Example 3: binding-solvents and -oils drain through porous substrates, increasing delamination potential.


Water-based interfaces formulated w/non-water soluble binders composed of styrene-acrylic alkali-soluble binder and resin emulsion.

Water-based interfaces formulated w/non-water soluble binders composed of styrene-acrylic alkali-soluble binder and resin emulsion.


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

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


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

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

Experimental Experimental ObjectiveDetermine effectiveness of an appropriate surface pre-

treatment technology in promoting /optimizing dry trap interlayer adhesions.

ProtocolAtmospheric plasma pre-treatment of polypropylene substrate Establishment of base interface adhesion-to-substrate threshold. Re-treatment over base interface to determine appropriate wet-out/adhesion.

ObjectiveDetermine effectiveness of an appropriate surface pre-

treatment technology in promoting /optimizing dry trap interlayer adhesions.

ProtocolAtmospheric plasma pre-treatment of polypropylene substrate Establishment of base interface adhesion-to-substrate threshold. Re-treatment over base interface to determine appropriate wet-out/adhesion.

Process Variables Specification Additional Specifications

Substrate BOPP film 0.5 mil.

Pre-Treat Surface Tension 30 mN/m Dyne solutions/contact angle

Water-Based Ink INX Lamiall® Cyan none

Solvent-Based Ink INX Lamiall® White PU-based; Acetate, alcohol

Treatment System Enercon Plasma Argon + oxygen

Treatment Density 6W/ft2/min Base and interlayer

Ink Application Method Pamarco Hand Proofer 165 line engraved roller

Ink Drying Method Hot Air Dryer 1 min. ; 4 min. room temp.

Test Ink Adhesion Method ASTM F2252-03 3M Scotch 800 tape; 180⁰

Experimental Experimental


Material: Polypropylene

Treatment: No post-treatment

Pre-Treat Tension: 37 mN/m

Result: 95% peel of ink






Treatment: Atmospheric Plasma

Post-Treat Tension: 48 mN/m

Result:


Material: PP + Solvent ink layer

Treatment: No post-treatment on solvent ink layer


Result: Spotty interlayer adhesion





Material: BOPP + Solvent ink layer

Treatment: Atmospheric Plasma over first ink layer

Post-Treat Tension: 39 mN/m at ink

Result: >99% interlayer adhesion





Base & Interlayer Adhesion Tape Peel of Blue Water-Based Ink on White Background


Base & Interlayer Adhesion Tape Peel of White Solvent-Based Ink on Black Background










Treatment: Atmospheric Plasma

Post-Treat Tension: 48 mN/m

Result:


Base & Interlayer Adhesion Tape Peel of White Solvent-Based Ink on Black Background

















Results & Conclusions Results & Conclusions 1) Dry-trapping of solvent/solvent and water-base/water-

base inks with common formulations and without interlayer surface pre-treatment created poor adhesion.

2) Plasma pre-treatment of base layer to a minimum of 8 mN/m above base dry ink film layer surface tension = >99% interlayer adhesion on polypropylene.

3) Indication of inherent benefit in modifying base layer of dry-trapped inks.

4) Micro-etching of ink surface + removal of wax films5) Oxygen formed hydroxyl groups and molecular bonds6) Additional trials suggested to improve interlayer

adhesion between coatings, adhesives, paints, etc.

Thank You for your attention!Thank You for your attention!

Trends in Surface Treatment for Multi-Layer PackagingTrends & Challenges – Multi-Film Structures...

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