Inkjet ink with non-swellable latex particles

#The global print market is in the process of transforming from analog printing to digital printing. Digital printing involves printing from a digital based image to a variety of media. Inkjet printing and electrophotographic printing are examples of digital printing techniques. These printing techniques have become increasingly popular for printing photographs and/or decorative art items.

#Features and advantages of examples of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, though perhaps not identical, components. For the sake of brevity, reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear.

#FIG. 1 is a flow diagram illustrating an example of a method for making an example of an inkjet ink;

#FIG. 2 is a schematic view of an example of a hybrid printing system suitable for use with an example of the inkjet ink disclosed herein; and

#The present disclosure relates generally to inkjet inks including non-swellable latex particles. Each non-swellable latex particle is a cross-linked polymer of an acrylic monomer and/or a vinylic monomer. Each acrylic and/or vinylic monomer used to form the cross-linked polymer has a molecular weight less than 1000. Larger monomers and/or resins (e.g., random copolymers) that are soluble in the non-polar carrier are not copolymerized with the acrylic and/or vinylic monomer having the molecular weight less than 1000. The particular monomers disclosed herein are capable of polymerizing and cross-linking to form the non-swellable latex particles, which are dispersible and substantially insoluble (i.e., solubility of less than 1%) in the selected non-polar carrier. In an example, the non-swellable latex particles are completely non-soluble in the selected non-polar carrier. Cross-linked latex particles are generally more rigid than latex particles formed with linear, non-cross-linked polymers. Rigid particles facilitate good jettability and long-term dispersion stabilization.

#By “non-swellable”, it is meant that the latex particles experience uptake of the non-polar carrier to an extent that the viscosity of the inkjet ink and the size of the latex particles are not substantially affected when the latex particles are added to the non-polar carrier. In other words, the cross-linked polymer matrix traps an amount of the non-polar carrier therein that is insufficient to swell the latex particles to the point of rendering them part of the non-polar carrier. In some instances, the non-swellable latex particles do not take on any of the non-polar carrier, and thus the viscosity and the particle size do not change. In other instances, the amount of non-polar carrier uptake is so small that the viscosity and/or particle size changes by equal to or less than 5% (i.e., % change in viscosity and/or particle size is from 0% to 5%). As such, the addition of the non-swellable, latex particles to the inkjet ink does not result in the formation of a soft gel, and thus the inkjet ink is readily jettable via a piezoelectric pen or printhead. The non-swellable latex particles disclosed herein are in contrast, for example, to polyethylene-based particles, which may swell in the non-polar carrier to the point of becoming part of the non-polar carrier. The swelling of polyethylene-based particles may be due, at least in part, to the molecular structure similarity between the polyethylene-based particles and the non-polar carrier.

#The non-swellable latex particles disclosed herein do not agglomerate or aggregate over time, which reduces sedimentation in the inkjet inks. As a result, the inkjet inks formed with the non-swellable latex particles disclosed herein are stable. The lack of agglomeration or aggregation is achieved without the addition of a copolymer resin (to the latex particle) that is soluble or even partially soluble in the non-polar carrier.