Uv ink

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WELL COME TO

UV INK

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Contents

bull Introductionbull UV Ink Requirementsbull Why UVbull UV Spectrumbull UV Curing Processbull Components of UV Inksbull Substratesbull Applicationbull Benefitsbull Limitationbull Drying Mechanism

bull Factors influencing UV Curingbull UV Machinery and Equipmentsbull Lampsbull Reflectorsbull Maintenance of Lamps and Reflectorsbull Rollers and Blanketsbull Testing Processbull Corona Requirementsbull Testing Equipmentsbull Storagebull Protective Measuresbull Troubleshooting

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Without Inks Thoughts would be Colorless

bull Identification

bull Protection

bull Decoration

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UV Ink Requirementsbull High Colour Strength ndash glossbull Fast curing for high production speedbull Low misting at high printing speedbull Adhesion on various pretreated substratesbull Good flow characteristicsbull Mechanical and Chemical Resistancebull Light Fastness

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UV Printing Inks

bull Itsrsquo Clean

bull Itsrsquo Fast

bull Itsrsquo Versatile

bull Itsrsquo Tough

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Spectrum

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What Is UV Curing

bull The conversion of liquid into a solid using Ultra Violet Light to initiate the drying process is known as UV curing system

bull 1st used industrially in 1940 to cure paints and coatings

bull The graphic arts industry embraced UV Technology only in the 70srsquo when 1st UV curable Lithographic inks were formulated

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bull OligomerMain component of the formulation Provides main coating characteristics

bull MonomersUsed to control viscosity and contributes to shrinkage flexibility cure speed etc Also part of the crosslinking reaction

bull Photoinitiator Absorbs UV light and initiates the polymerization

reactionbull Pigment amp Fillersbull Additive ndash Surfactants DefoamersTackifiers etc

Components of A UV Formulation

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UV Ink Raw Materials

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Substrates Used for UV Inks

bull Paperbull Boardbull Plastic Filmbull Metallised Paperbull Aluminium Metal

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bull Printing Process Application Areas

bull 1 Offset Sheet-fed 1 Over Carton- Boardbull 2 Web-fed Offset 2 For Business forms direct

mail lottery ticketsbull 3 Screen Printing 3 Paper Synthetic Substrate

CD Credit Cardsbull 4 Flexography 4 Paper or Synthetic substrate for labelsbull 5Letterpress 5 Paper or Synthetic substrate for labels

Application of UV Inks

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Converting amp Printing Applications

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bull An instantaneous drying process which givesHigher Productivity and Immediate post-processing

bull Dependable Drying Process which Minimizes the risk of Set- Offs amp Gives higher physical amp chemical Resistance with Excellent performance properties and Improved Aesthetics

bull Ecologically Cleaner Drying Process No VOCsrsquo during curing process ( Solvent Free )

bull Versatile Substrates including Heat Sensitive Materials

bull Compact Lamp systems contrast with Large IR or Hot Air drying Ovens ndash Reduced Floor Space Requirements

bull In-line processing capability and minimal manufacturing steps bull Energy Savings

Benefits - UV Process

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bull High capital equipment costbull High material costbull Life of lampsbull Cleaning chemicalsbull Special rollers amp blanketsbull Plates bakingbull Shelf life and storagebull Personal protection Skin Irritant

Limitations ndash UV Process

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Polymer Cross Linking by a lsquochemical processrsquo initiated by UV Radiation

Drying Mechanism

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UV Cure

Free Radical UV Curing Mechanism

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Factors Influencing UV Curing Efficiency

bull Colours ( Pigmented amp Non- Pigmented) bull Film weight thickness bull Substrates (absorbent non-absorbent)bull Design layout (screen solid printing)bull Press speedbull Type of UV lampsbull Age of the UV lampsbull Efficiency of the UV - Radiatorsbull Type (Construction) of the reflectorsbull With or without interdeck curing

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UV Machinery amp Equipment

A Emitters

B Reflectors

C Cooling

Systems

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Typical UV equipment consists ofbull Lamp (or bulb) the electrical energy supplied to the bulb is converted into UV energy inside it bull Type of lamp (electrode electrodeless pulsed spot) bull Spectral output of lamp (ldquoHrdquordquoDrdquordquoVrdquo) bull Length of lamps (long lamps tend to sag) bull Reflector (elliptical parabolic diachronic) bull Focusedunfocused reflectors bull UV lamp output (200 to 600 wattsinch) bull Curing atmosphere (N2 ambientdry air) bull Required UV exposure (dwell time) bull Acceptable window of equipment operationbull Lamp housing reflects and focuses the UV energy

generated by the lamp (delivers the UV to the substrate)

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Composed of a Quartz Tube ( inside of which contains typically Mercury in an Inert Atmosphere)

Conventional Electrode Type (Arc Lamp)

10487071048707200 to 750 wattin power 10487071048707Lengths up to 72 inches 104870710487072 to 3 min start up time 104870710487071000 hour typical life

UV Lamps

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Medium Pressure Mercury Vapor Lamp

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Reflectors Types

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Heat Management

IR=45

UV=30 Visible=25

UV=30 Visible=25 IR=45

UV=30 Visible=25 IR=45

UV=30 Visible=25 IR=45

High Heat Output From Mercury Vapor Lamps (typical more than 50 of output is IR)

Cooling is Required

bull Air cooling (inerting difficult)bull Water cooling

bull Chill drumsbull Constant moving webbull Shuttersbull IR filtersbull Dichroic Reflectors

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bull Clean reflectors amp lamps weekly by IPA with a smooth cotton cloth

bull Avoid frequent on amp off of lampbull Do not touch lamp with fingersbull Avoid dusty atmosphere nearby the lampsbull Do not open the dryer while runningbull Maintain the lamp cooling system

Maintenance of Reflectors amp Lamps

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bull EPDM ndash In varnishes (shore hardness- 40)

bull NITRILE ndash More useful in inks (shore hardness- 30-35)

bull Nylon plates

Blankets amp Rollers

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Possible Test Methods

bull Talcum Powder testbull Graphite Powder Testbull Tape Testbull MEK resistant testbull Potassium

permagnate Testbull Product Resistant

( Smear ) Test

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Corona Requirement

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Laboratory Testing Equipments

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bull Keep away from Heat amp Direct Sunlight

bull Below temperature of 22deg C

bull Prefer to pack in Opaque container

bull Stock rotation is essential to avoid outdated stock

Storage of UV Products

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bull Avoid skin-contact with UV products amp additivesbull Proactive gloves amp goggles should be wornbull Contaminated or soaked clothing should be

removed immediatelybull Never look directly at the UV Lampsbull If any contact is made with the skin it should be

washed immediately with soap

Protective Measures

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Adhesion Ink can be removed easily when Tape Test is done

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Curing ndash Ink film remains tacky or wet to touch

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Dot Sharpness Halftone Dots increase in size causing printing screen and reverses to be plugged and appear muddy

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Ghosting A printed area from another part of the form appears in large solids or dense halftones

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Picking Lifting off of coating from coated stock and pulling fibres from uncoated stock

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Wet Trapping Cannot achieve good coverage of one ink printing on top of another when not using the interstation lamp

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Backing Ink backing away from fountain roller resulting in color variation

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Hickies Blank area with a dot in the middle generally caused by a particle

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THANK YOUby

RONAK JOSHI