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Coating Blankets
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What is a coating?
A coating is a clear layer applied to all, or part of asheet after printing - achieving a variety of finishes.
Before drying, most coatings are opaque liquids,quite unlike a sheetfed ink.
Coating is commonest in carton printing, but alsowidespread in commercial printing.
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In-line and off-line coating
In-line coating - Printed then coated on the same press in one pass.
Off-line coating - Printed then coated as a separate process on another machine.
PRINTING COATINGDEDICATEDCOATING UNITS
PRINTINGCOATING
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Why are sheets coated?
Improved appearance - higher gloss, brighter look,special finishes etc.
Protection - stops the image rubbing, scuffing etc.(also known as a sealer).
Faster processing - cutting and creasing etc.
Sometimes two coatings are applied to a sheet (double
coating).
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Coating types
Chemistry/drying process:
Aqueous (or water based/dispersion) - dried with hotair or infra red radiation (80% of the market).
UV - dried with UV radiation (20% of the market).
Finish:
Gloss
Satin
Matte
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Terminology
Gloss:
The ability of a surface to reflect directed light.
Has an effect on colour and brightness.
Slip:
The slip value of a coating is chosen to suit processing(folding/gluing) and/or the final application.
Laydown:
How smooth and even the coating appears.
Bad laydown means mottle or orange peel effect. More critical on matte than gloss coatings.
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Coating terms and types
Knock outs or glue flaps (75% of cartonmarket)
Selected areas only, e.g. carton work.
No fine details.
Use a Coating Blanket.
Flood coating (15%)
Whole sheet coated, no detail. Use any Printing Blanket.
Spot coating (10%)
Detailed text or halftones.
Use photopolymer plate (Cyrel, Nyloprint etc).
Alternatively use a litho varnish (clear ink).
Spot coatingfor detailed
work
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Why bother with knock-outs?
Coatings can cause problems in carton printing.
Glues wont stick to most coatings.
Nor will inks used to print sell by dates etc.
Areas of the blanket must be cut and stripped away tomake a STENCIL so they will not transfer coating.
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Knock outs and glue flaps
Coated areas
Non coated areas
Carton coating design
Glueflaps
Date box
Coating blanket
stripping patternNon stripped areas
Stripped areas
Glue flap outline
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How is the stencil prepared?
Cut by hand - on or off press
Cheap but inconsistent, lessaccurate.
Cut by CAD/Plotter
Fast and accurate.
The blanket is always stripped by hand!
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Roller versus Anilox coater
Impression cylinder
Plate/blanketcylinder Fountain
roller
Paper/board
Coating
Coatingroller
Impression cylinder
Plate/blanketcylinder
Doctorblade
Paper/board
Coating
Anilox
roller
Anilox coater unit
The anilox roller is solidmetal or ceramic, with tinycells in its surface.
The coating film weight iscontrolled by the cell size.
Roller coater unit
The coating roller is coveredwith solid rubber.
The coating film weight iscontrolled by pressurebetween the rollers.
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Why use a Duco stripping blanket?
Dedicated coating blanket design.
Consistent stripping properties.
Optimum coating properties.
High smash resistance/durability.
Widest range available.
3 different backing options.
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Whats wrong with the alternatives?
Old printing blankets
Poor and inconsistent stripping properties.
Poor and inconsistent coating performance.
Often damaged by smashes etc.
Photopolymer plates
High costs - can be up to 4 x coating blanket cost. Easily damaged - printer may have to buy spare.
Availability - off site processing.
Limited gauge range. Processing waste.
Environmental impact - chemical usage.
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Duco coating blanket range
Worlds largest range of coating blankets.
Available in gauges from 0.90mm to 1.95mm.
Fabric backed Polyester backed Sticky backed
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Duco coating blanket range
BaseCastAdhesive0.95, 1.05,
1.68 & 1.95
Superstrip SB
SpongeCastPolyester1.95Superstrip PB &
UVPB
SpongeCastPolyester1.95Superstrip PB
Ultra
BaseMicro ground
(*also cast)Polyester
1.15, 1.30*,
1.35 & 1.40Superstrip PB
SpongeCastFabric1.68 & 1.95Superstrip FB &
FBLR
Strip toSurfaceBackingGaugesProduct
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Duco coating blanket range
1.68Mitsubishi
1.95Ryobi
1.95Komori
1.30 1.40KBA
1.95Manroland
1.95Heidelberg
Compatible blanket gaugePress type
Please considerthat thinnercoating blanketsor plates may beused with the
appropriateadjustment inunderpacking.
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