Process and materials for marking plastic surfaces

A method of producing ink-jet printed images on plastic surfaces, comprising the steps of:

• a. providing a plastic object;
• b. coating at least part of the surface of the plastic object with a mixture containing a chemically cross-linkable system;
• c. evaporating off the volatile part of the mixture, thus depositing a
• solid hydrophilic layer on the surface of the plastic object without causing the coating to cross-link;
• d. providing an ink-jet ink comprising a non-reactive colorant and aqueous carrier;
• e. jetting the ink by means of an ink-jet system onto the surface of the coating on the plastic object so that it is absorbed into the coating;
• f. providing energy in sufficient quantity to the printed surface to cross-link the entire surface coating including the absorbed ink-jet inks to form a non-smearable print.

A method of producing ink-jet printed images with high resistance to physical and chemical damage on plastic surfaces, comprising the steps of:

• a. providing a plastic object;
• b. coating at least part of the surface of the plastic object with a solution containing a mixture of a hydrophilic polymer or polymers together with a hydrophobic polymer;
• c. evaporating off the volatile part of the coated solution, thus depositing a solid film on the surface of the plastic object;
• d. providing an ink-jet ink comprising a colorant and aqueous carrier;
• e. jetting the ink by means of an ink-jet system onto the surface of the coating on the plastic object;
• f. warming the printed surface to drive part of the water in the ink into the surface coating and to evaporate the other part of the water, as well as causing cross-linking of the deposited layer;
• g. over-coating the dried surface with a water-based coating;
• and
• h. heating the over-coating to seal-in the previously deposited ink and coating.