Photosensitive resin plate

Liquidcuringtype

Liquidcuringtypephotosensitiveresinplate,referredtoasliquidresinplate.Beforeexposure,theresinisaviscous,transparentliquid,andcrosslinksintoasolidstateafterexposure.

1.Thecompositionoftheliquidresinplate

Themaincomponentsoftheliquidresinplateareresin,crosslinkingagent,photoinitiator,polymerizationinhibitorandsoon.

Resinisthemaincomponentofthephotosensitiveresinplate,generallyanunsaturatedresinobtainedbypolycondensationofaliphaticandaromaticsaturatedandunsaturatedpolycarboxylicacidsandglycols.

Theroleofthecrosslinkingagentistomaketheliquidorsolidresinpolymerizeandcrosslinkundertheactionofultravioletraystobecomeasolidorincreasethehardnessofthesolid.Commonlyusedcross-linkingagentsincludeacrylicacid,acrylamide,oxalatedimethacrylate,ethyleneglycolacrylateandsoon.

Photoinitiatorisalsocalledphotosensitizer,whichisamediumfortransmittinglightenergyinphotopolymerizationreaction.Commonlyusedarebenzoinanditsethers.

Polymerizationinhibitorsaresubstancesthatinhibittheoccurrenceofdarkreactions,andp-phenylenediamineiscommonlyused.

2.Plate-makingprocessofliquidresinplate

Theplate-makingprocessofliquidresinplate.Generally,itneedstogothroughthestepsofflow,exposure,washing,dryingandpost-exposure.

(1)Layingistoinjectthepreparedphotosensitiveresinintothehopperoftheexposuremoldingmachine.Whenthephotosensitiveresinflowsoutofthehopper,thescraperatthetopofthehopperscrapesthedischargedphotosensitiveresintoacertainthickness.

(2)Exposureistocoverthelayeredphotosensitiveresinwithatransparentfilm,andthenputapositivenegativeimagefilm,thefrontexposureiscarriedoutfirst,andthenthebackexposureiscarriedout.Theexposuretimeofthenextmasterisgenerally10timesofthebackexposuretime.Ahigh-pressuremercurylampwithrichultravioletraysiscommonlyusedasalightsource.

(3)Washingistoputtheexposedphotosensitiveresinplateintothedevelopingmachineandwashitwithdilutesodiumhydroxidesolution(concentrationabout3～5%),andkeepitatabout35℃..Theresinthathasnotundergonephotopolymerizationandcrosslinkingisdissolvedintheabsenceoflight,leavingaphoto-hardenedimageandtextpartonthefilm.

(4)Dryingandpost-exposurearetoputthewashedphotosensitiveresinplateintoaninfrareddryerfordrying.Afterthephotosensitiveresinplateisdried,anotherpost-exposureisperformed,thepurposeofwhichistoincreasethemechanicalstrengthoftheprintingplateandimprovetheprintingdurability.

Liquidresinplateisaready-to-coatplatewithlowpriceandpoordimensionalstability.Theexpansionandcontractionofthelayoutisgreatlyaffectedbytemperatureandhumidity.Itissuitableformakingsmall-formatlineortextprintingplates,mainlyforprintingbooks.Thebodyofthetext.

Solidhardeningtype

Solidhardeningphotosensitiveresinplate,referredtoassolidresinplate.Thebaseofthepolyesterfilmiscoatedwithphotosensitiveresin,andtherelief-likereliefplatecanbeobtainedafterexposureandwashing.

1.Thecompositionofthesolidresinplate

Commonlyusedsolidresinplatesincludepolyvinylalcoholrecoveryresinplatesandphotosensitivenylonplates.

Compositionofsolidresinplate

Nameresincrosslinkingagentphotoinitiatorpolymerizationinhibitor

Polyvinylalcoholversionpolyvinylalcohol(polymerizationdegree300-1000)Hydroxymethylacrylamideα-hydroxymethylbenzoinmethyletherhydroquinonep-methylphenol

Nylonversionalcohol-solublecopolymernylonN,N′-methylenebisacrylamidebenzophenoneHydroquinone

2.Theplate-makingprocessofthesolidresinplate

Theplate-makingprocessofthesolidresinplateisbasicallythesameasthatoftheliquidresinplate.Itmustundergoexposure,washing,dryingandpost-exposure,butthereisanextraheatThecuringprocess.Thefollowingtakesthepolyvinylalcoholphotosensitiveresinplateasanexampletobrieflydescribetheplate-makingprocessofthesolidresinplate.

Theexposureiscarriedoutintheexposuremachine.Exposethepositivenegativefilminclosecontactwiththeresinplate,andgenerallychoosealow-powercoldlightsourcewithrichultravioletrays.

Flushingisinthewashingmachine,usingwarmwateratatemperatureof45～50℃,andthewaterpressureisgenerallycontrolledat2～2.5kg/cm2.

Dryingandpost-exposurearetoexposethewashedpolyvinylalcoholreliefplateafterbeingdriedbyhotair.Itisalsopossibletouseadryerwithanultravioletlightsourcetoexposewhiledrying.

Heatcuringistoputthedriedandpost-exposedreliefplatesintoanovenat120°Cto130°Cforthermalcuringtodehydratethepolyvinylalcoholtoincreasethehardnessoftheprintingplate.

Thesolidresinplateisapre-coatedplatematerial,withgoodflatnessandstabledimensions,andcanbeusedtomakescreenpatterns.Althoughtheprocessissimple,thecostishigherthanthatoftheliquidresinplate.