Pigmented ink composition
AssigneeSicpa Holding SA
InventorsXavier Marguerettaz, Thomas Tiller, Edgar Muller, Frederic Gremaud, Sylvain Jaquier
Life of this patent
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Abstract
Re-dispersible pigmented printing ink compositions, preferably for the continuous ink jet printing process are obtained by the addition of a flocculating agent to the pigment dispersion in the printing liquid. The compositions do not form hard sediments and are easy to re-disperse on stopping and resuming the printing operations. Suitable flocculating agents bind the pigment particles in the sediment into three-dimensional “airy” structures, which are easy to break up. The ink compositions of the invention are furthermore characterized by a good printability in the dispersed state.
Claims11
A redispersible pigmented printing ink composition for the continuous ink-jet printing process, said ink composition having a viscosity in the range of between 2 and 10 mPas said ink composition comprising
- at least one solvent selected from the group consisting of water and organic solvents of the group of alcohols, ketones and esters,
- a binder system in an amount between 0.5% and 20% by weight of the total ink which comprises at least one polymer compound selected from the group consisting of thermoplastic resins, and
- at least one inorganic luminescent pigment selected from the group consisting of crystalline compounds comprising activator-doped zinc sulfides, oxysulfides, vanadates, fluorides, oxides and oxyfluorides of yttrium or the rare-earth elements of the periodic table, and mixtures thereof,
- conductivity control agents, and
- at least one flocculating agent forming a re-dispersible sediment of said pigment in said composition, wherein said flocculating agent is selected from the group consisting of inorganic salts of aluminum, calcium and iron (III), and of organic polymers carrying functional groups able to interact with and bind to the surface of said pigment particles, and wherein said flocculating agent is present in a concentration range of 0.01 to 20% of the inorganic pigment weight.
Dependencies are inferred from the claim text.