Electron Beam Technology for Converting Applications

Stephen C. Lapin, Ph.D.PCT Engineered Systems, LLC

Davenport, IA

Background:Electron Beam Technology

Accelerated electrons generated by electrically operated filamentsEnergy of electrons determined by acceleration potential

Low voltage typically defined as less than 300 kVPenetration determined by voltage and substrate density

Electrons will ionize most organic and polymer materialsMaking and breaking of chemical bonds is the basis for crosslinking and curing (polymerization)Typical applied energy (dose)

Crosslinking: 25 to 150 kGy (2.5 to 15 Mrads)Curing: 20 to 40 kGy (2 to 4 Mrads)

Background:Electron Beam Equipment

Industrial processorsIn use for more than 30 yearsOperates up to 300 kVWeb widths up to 130 inchesThroughput up to 5000 MRFPM (5 Mrads @ 1000 ft/min)

New generation lower voltage processorsOperates at 70 to 125 kVLower cost and smaller size compared to original industrial equipmentIdeal for many printing, packaging, and converting applicationsThroughput up to 3600 MRFPM (3 Mrads @ 1200 ft/min)

New compact modular processorsModular 10 and 16 inch wide emittersOperates at 70 to 150 kVPermanent vacuumSurface sterilization applicationsPotential for narrow web applications

Scanning beam processors – limited use in web applications

Electron Beam Equipment

Industrial Electron Beam Processor New Generation Low VoltageElectron Beam Processor

Electron Beam Advantages

Lower energy usage compared to thermal dryingSmall footprintNear zero VOCsInstantaneous curingHigh line speedsConsistent outputImproved product performance

UV/EB ComparisonUV

Photoinitiator required for curingSurface curing in air or inert atmosphereLight penetration needed for curingMultiple lamps needed for wide/high speed processingHigh heat output from mercury lampsOutput variation with age and across width of lamp

EBNo photoinitiator neededSurface curing requires inert (N2) atmosphere (not need for laminate processes)Penetrates opaque materialsSingle EB unit will cure >100 inches wide at >1000 ft/minCooler, more energy efficient processConsistent output and uniformity

Low Voltage ElectronBeam Applications

Printing and Packaging ApplicationsInk curing: web off-set, flexo (WetflexTM)Overprint Coatings: laminate replacement, cold seal release, multi-wall paper bags, outdoor film bagsLaminating Adhesives: folding cartons, flexible packaging

Converting ApplicationsNon-printing applicationsMay include converting of substrates that are subsequently printed

Electron Beam Ink CuringWeb Offset Carton Production

EB Converting Applications

Film CrosslinkingPressure Sensitive Adhesive CrosslinkingDirect CoatingLaminatingTransfer CoatingBackside EmbossingTopside Embossing

Film CrosslinkingELECTRON

BEAM

UNWIND(or direct from

film production)REWIND

TREATED FILM

Film CrosslinkingLargest single EB applicationPolyethylene and polyethylene copolymers are well known to undergo crosslinking upon EB irradiationOther polymers may undergo chain scission or a combination of scission and crosslinking depending on the polymerMost common use of polymer crosslinking is to create heat shrinkable filmsCrosslinking is also be used to modify the physical and thermal properties of various films

Pressure SensitiveAdhesive Crosslinking

ELECTRON BEAM

UNWIND REWIND

OPTIONALRELEASE

LINEREXTRUDER

Pressure SensitiveAdhesive Crosslinking

Hot melt, syrups, solvent, and water based PSA’s may be EB crosslinkedEB Crosslinking of hot melt adhesives improves sheer, heat, and chemical resistanceEB crosslinked hot melt PSAs provide alternative to solvent acrylic PSAsApplications include free film adhesives, high performance tapes, and label stock

Direct CoatingELECTRON

BEAM

UNWINDCOATER

REWIND

Direct CoatingRelease coatings

Premium silicone release liners for PSAsIndustrial release coatings (silicone and non-silicone)

Coatings for vacuum metallizationPremetallization primersMetal protective coatings

Enhance/preserve barrier propertiesCorrosion protection

Protective coatingsFurniture and countertop laminatesCrosslinking provides stain and scratch resistance

Pigmented and filled coatingsEB penetrates opaque coatingsExamples: magnetic media, abrasive binders

Adhesive Laminating

ELECTRON BEAM

PRIMARYUNWIND

COATERREWIND

SECONDARYUNWIND

Adhesive LaminatingEB advantages

Stable one component adhesivesRoom temperature applicationWill cure through opaque filmsInstant bonding – immediate QC, slitting, die cutting, shipping

Current commercial packaging applicationsFlexible packaging (film-to-film and film-to-paper)Folding cartons (film-to-paperboard)

Converting applicationsPaperboard and plastic card stock - lamination of metalized, holographic, and specialty films Paper, film, and foil – prelaminated packaging and industrial substratesInstant bonding enable in-line laminating with other converting processes

Transfer Coating

ELECTRON BEAM

PRIMARYUNWIND

TRANSFERADHESIVE

PRECOATEDCARRIER

CARRIERREWIND

TRANSFERCOATEDREWIND

SECONDARYUNWIND

Transfer CoatingEB advantages

No solvent or water to dryCool process allows transfer to heat sensitive substratesLow adhesive weightsInstant curingPermanent bond

ApplicationsTransfer metalliztionDecorative and specialty transfer coatingsPattern printing of adhesive produces transfer pattern (no stamping dies required)Highly uniform surface defined by casting on the original carrier film

Backside Embossing

ELECTRON BEAM

EMBOSSEDDRUM

COATERREWINDUNWIND

EMBOSSEDPATTERN

Backside EmbossingEB advantages

No solvent or water to dryCure through opaque materials including paperClean release from embossed metal drumPattern reproduction more accurate than thermal embossingWide feature size (from microns to inches)Crosslinks EB coatings have high chemical and thermal resistance

ApplicationsCasting papersUnique tactile effectsUnique optical effects

HologramsReflective materialsLenticular

Topside Embossing

ELECTRON BEAM

UNWINDCOATER

EMBOSSED FILM LOOP

REWIND

EMBOSSED PRODUCT

Topside EmbossingEB advantages

No solvent or water to dryPattern defined by “parent” film (roll or loop)Cure through clear or opaque parent filmClean release from select parent film materialsParent film may be registered to printed webWide feature size (from microns to inches)Crosslinked EB coatings have excellent durability

ApplicationsDecorative packagingUnique tactile effectsUnique optical effects

ConclusionsEB may be used in wide variety converting applicationsEB provides environmental and energy saving advantages compared to thermal curing processesThe nature of EB technology can enable unique converting processesThe development of smaller, lower cost equipment, makes EB an attractive technology for expanded use in converting applications

Thank You

Questions?

Steve LapinPCT Engineered SystemsSCLapin@TeamPCT.com