PROCESS FOR PRINTING IMAGES ON DARK SURFACES
Novel processes for printing high quality, high resolution, multi-color images on darkly colored fibrous or porous materials or other ink absorbing materials, is disclosed. The processes are effected by digitally printing a layer of an opaque, lightly colored ink composition, followed by digitally printing the colored image thereon, and optionally further involve applying a wetting composition prior to and/or subsequent to these printings. Processes utilizing wetting compositions and/or liquid ink compositions which can interact therebetween so as to effect a chemical and/or physical change in one or more of these compositions are further disclosed.
1 . A property-sensitive inkjet composition, comprising a property-sensitive agent, a dispersed pigment and an ink carrier, wherein said property-sensitive precipitated upon contacting a wetting composition that comprises a wetting carrier and a property-adjusting agent, thereby causing an increase in a viscosity of the property-sensitive inkjet composition.
2 . The inkjet composition of claim 1 , suitable for directly printing an image on a surface of substrate when said contacting is effected on said surface.
3 . The inkjet composition of claim 1 , wherein said substrate is selected from the group consisting of a textile fabric, a paper, a wood and a plastic.
4 . The inkjet composition of claim 1 , wherein said property is a chemical and/or physical property selected from the group consisting of acidity (pH), ionic strength, solubility, hydrophobicity and electric charge.
5 . The ink composition of claim 4 , wherein said property-adjusting agent is selected from the group consisting of an acid, a base, a salt, a charged polymer, an oxidizing agent, a reducing agent, a radical-producing agent and a cross-linking agent.
6 . The ink composition of claim 5 , wherein said property-adjusting agent is an acid.
7 . The ink composition of claim 5 , wherein said acid is an organic acid.
8 . The ink composition of claim 7 , wherein said organic acid is selected from the group consisting of a carboxylic acid such as, for example, a carbonic acid, a formic acid, an acetic acid, a propionic acid, a butanoic acid, an α-hydroxy acid such as glycolic acid and lactic acid, a halogenated derivative thereof and any combination thereof.
9 . The inkjet composition of claim 1 , wherein said property-sensitive agent is selected from the group consisting of a dispersing agent, a resin binder, an adhesion promoting agent, a viscosity modifying agent, a thickener agent, a surface tension modifying agent, a surface active agent, a surfactant and a softener.
10 . The inkjet composition of claim 9 , wherein said property-sensitive agent is an acrylate polymer, a polyurethane emulsion, a polyurethane polymer, a polyether polymer, a polyester polymer, a polyacrylate polymer, a polyvinyl chloride polymer, a polyvinyl acetate polymer, a polyvinyl butyral polymer, an aminosilicon polymer and any combination thereof.
11 . The inkjet composition of claim 9 , wherein said property-sensitive agent is a dispersing agent.
12 . The inkjet composition of claim 9 , wherein said property-sensitive agent is a resin binder.
13 . The inkjet composition of claim 12 , wherein said resin binder is an acrylic resin selected from the group consisting of a Johncryl® acrylic resin and an Acronal® acrylic emulsion.
14 . The inkjet composition of claim 1 , wherein said ink carrier is an aqueous carrier.
15 . The inkjet composition of claim 1 , wherein said wetting carrier is an aqueous carrier.
16 . The inkjet composition of claim 1 , being curable by heating said surface and/or drying said surface.
17 . An inkjet composition, obtainable by contacting said property-sensitive inkjet composition of claim 1 with said wetting composition.