Dispersion varnish

also water-based paint, water paint box

Finishing with emulsion paint is used very frequently and takes a high value due to the short drying time. Dispersion paint is not used only for processing, but also as a protective coating (e.g. as protection against yellowing).

Technical background

The dispersion coating consists essentially of water and binders(resins). Surfactants stabilize these dispersions. If the paint transferred to the substrate, the water begins to evaporate or fails in a very absorbent material away additionally. By the decrease of the water dispersed polymers are approaching each other and can crosslink completely by the touch. The mission of the lacquer layer is applied wet-on-wet in the sheet-fed offset press with a special coating unit. The coater consists either of an anilox roller, a doctor blade chamber and an applicator roll(comparable to a flexographic printing) or from a dive and applicator roll. By means of photopolymer printing plates can scale and/or partial coatings are applied. Are also possible special coating plates made ​​of rubber for full-surface finishes. The printing machines are also equipped with drying facilities(e.g. hot air or IR drying). For the paint job is also the screen printing method offers, which allows transmission of higher layer thicknesses. This, however, an additional step beyond the offset press is necessary, thereby increasing the cost and extended the production run.

Effect

Dispersion coatings can be compared to the classic oil-based varnish intense gloss and matt effects can be achieved. Special optical effects can be achieved by effect pigments in the paint. The printed products have a high stacking strength and abrasion resistance. Also for improved lubricity or frozen strength dispersion paints are used.

Application possibilities

It can print on paper and cardboard, plastics for special types of coatings are used. Particularly with absorbent material, a primer should be applied before painting, it seals the surface and prevents the penetration of the resin pigments in the printing.

Limitations

The further processing of such products in bookbinding can be difficult because the paint layer is very brittle and can break easily. The creasing, folding and embossing are therefore also limited. This should be considered when determining the layout. On the dispersion varnish layer should not be printed. The painting of metallic inks may cause discoloration or flaking. Paper with a basis weight below 90g / m² can be dimensionally unstable(wave formation) by the absorption of moisture.

Costs

This printing process can only be realized in presses with special configuration and an extra coating unit. This results in higher costs and a higher price for the product, which is higher than the oil pressure paint. The size of the area to be painted, the gloss required for the effect thickness and to the use of effect pigments in addition determine the level of cost.

Sources and additional literature

[1] Kipphan, Helmut: Handbuch der Printmedien – Technologien und Produktionsverfahren; Springer-Verlag Berlin Heidelberg, 2000, Seite 148

[2] Kleeberg, Dieter: Inline-Druckveredelung mit Lack. KBA Process Nr. 4, Ausgabe 1/2007

[3] Hille, Frauke Helene: Veredelungsmöglichkeiten und Spezialeffekte für Bücher und Broschuren; DIPLOMARBEIT, Hochschule für Technik, Wirtschaft und Kultur Leipzig (FH),Fachbereich Medien, Studiengang Verlagsherstellung, 2008

[4] Beckmann, Till; Morlok, Franziska: “Extra: Enzyklopädie der experimentellen Druckveredelung“; 1.Auflage 2009, Birkhäuser Verlag

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