A coating is a clear layer applied to all, or part of a sheet after printing - achieving a variety of finishes.

Transcription

1 Coating Blankets

2 What is a coating? A coating is a clear layer applied to all, or part of a sheet 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 also widespread in commercial printing.

3 In-line and off-line coating In-line coating - Printed then coated on the same press in one pass. PRINTING COATING DEDICATED COATING UNITS Off-line coating - Printed then coated as a separate process on another machine. PRINTING COATING

4 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).

5 Coating types Chemistry/drying process: Aqueous (or water based/dispersion) - dried with hot air or infra red radiation (80% of the market). UV - dried with UV radiation (20% of the market). Finish: Gloss Satin Matte

6 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.

7 Coating terms and types Knock outs or glue flaps (75% of carton market) 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 for detailed work Spot coating (10%) Detailed text or halftones. Use photopolymer plate (Cyrel, Nyloprint etc). Alternatively use a litho varnish (clear ink).

8 Why bother with knock-outs? Coatings can cause problems in carton printing. Glues won t stick to most coatings. Nor will inks used to print sell by dates etc. Areas of the blanket must be cut and stripped away to make a STENCIL so they will not transfer coating.

9 Knock outs and glue flaps Carton coating design Coated areas Non coated areas Date box Glue flaps Coating blanket stripping pattern Non stripped areas Stripped areas Glue flap outline

10 How is the stencil prepared? Cut by hand - on or off press Cheap but inconsistent, less accurate. Cut by CAD/Plotter Fast and accurate. The blanket is always stripped by hand!

11 Roller versus Anilox coater Roller coater unit Anilox coater unit Plate/ blanket cylinder Coating roller Fountain roller Plate/ blanket cylinder Anilox roller Doctor blade Paper / board Coating Coating Paper / board Impression cylinder Impression cylinder The coating roller is covered with solid rubber. The coating film weight is controlled by pressure between the rollers. The anilox roller is solid metal or ceramic, with tiny cells in its surface. The coating film weight is controlled by the cell size.

12 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.

13 What s 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.

14 Duco coating blanket range World s largest range of coating blankets. Available in gauges from 0.90mm to 1.95mm. Fabric backed Polyester backed Sticky backed

15 Duco coating blanket range Product Gauges Backing Surface Strip to Superstrip FB & FBLR 1.68 & 1.95 Fabric Cast Sponge Superstrip PB 1.15, 1.30*, 1.35 & 1.40 Polyester Micro ground (*also cast) Base Superstrip PB & UVPB 1.95 Polyester Cast Sponge Superstrip PB Ultra 1.95 Polyester Cast Sponge Superstrip SB 0.95, 1.05, 1.68 & 1.95 Adhesive Cast Base

16 Duco coating blanket range Press type Heidelberg Manroland Komori KBA Mitsubishi Compatible blanket gauge Please consider that thinner coating blankets or plates may be used with the appropriate adjustment in underpacking. Ryobi 1.95

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