Digital Waterborne Inks that unlock the possibility of industrial printing on Plastic Films
An ultimate challange
Digital printing on flexible films with water-based inks is an ultimate challenge of the printing sector, although it is widely demanded in applications, that are still in transition from conventional to digital printing, like luxury vinyl tiles (LVT) or flexible packaging. Compared to solvent or UV inks, water-based inks are low VOC formulations, contain no polemic photo-initiators and deliver a thin dried-up ink layer, which does not significantly affect the flexibility of the films.
Resoluble “Digital” Binders : ESAJET®
Water-based inks printing on flexible films is a complex process because there is a risk to unbalance the fragile equilibrium that links print reliability with ink drying properties and performance of the printed material. Unlike printing on porous material, printing on a non-porous substrate requires the ink to dry faster than usual to deliver a good print quality. This means reducing the amount of humectants, in particular glycols with a high boiling point, which, in turn, contributes to the faster evaporation of water inside the nozzles.
On the other hand, the printed film is an intermediate product, which needs to show a good adhesion, lamination or scratch resistance. This means using binders delivering high application performance, which are generally good film-formers and put the printhead integrity even more at risk when the ink contains a minimal amount of humectant.
In order to restore this equilibrium, we have developed the ESAJET “Digital” binders range, based on polyurethane and acrylic dispersions, that provide an outstanding lamination strength while offering a good ink re-solubility in presence of low humectant levels.
ESAJET® Digital Binders
New development with improved resolubility for prints onto plastics, intended to be laminated afterwards, either with glue (e.g. PP, PET) or heat (e.g. PVC).
Binder with good adhesion and lamination strength on plastics in general
Hard binder for surface printing. Good adhesion strength to plastics
Self-crosslinkable acrylic binder with excellent fastness properties and compatibility to a wide range of dispersions
Transparent and moisture resistant receptive coatings: ESACOTE PU
The absence of porosity of the flexible films impedes to remove water and glycols of the inkjet ink by absorption. Relatively large amounts of low viscosity ink stand in liquid form on the surface of the substrate before an auxiliary drying device speeds up the evaporation process. During that time interval, the ink is prone to “move” laterally creating printing defects like bleeding, mottling and craters.
To prevent the degradation of the print definition when the ink is still “wet”, we can prime the film with hydrophilic swelling materials, like CMC or silica gel, that will quickly remove water from the incoming ink droplets and deliver a good print definition. However, that generates a translucent or opaque printable layer, which is often detrimental to the further use of the printed film. For example, reverse printing for food packaging will not cast the expected shine, or the lamination strength of a printed film will be insufficient. Therefore this process is limited in some graphic applications and not fit for industrial film applications.
To overcome this issue, we have developed a dedicated range of binders for the formulation of digital primers, that helps to maintain the print definition without losing the film transparency, lamination performance and moisture fastness required in certain food packaging applications.
Cationic binder modified in order to increase reactivity with the ink and improve print definition. Very low hygroscopicity
Cationic binder with low hygroscopicity , gives a wide operation opportunities to formulators
Besides those targeted solutions, we have a wide portfolio of other generic ingredients to prepare premium inks. We rely on our Lamberti core technologies to offer an extensive range of FLUIJET® dispersants for pigment dispersions, thickeners to increase the inkjet ink viscosity to the specifications of high-viscosity printheads, without resorting to massive amounts of glycol, and wetting agents to control the print-through and print definition