Aqueous ink jet ink compositions and uses
Aqueous ink jet ink compositions can be used for ink jet printing colored or invisible images on receiver elements. These compositions contain a polymeric agent comprising core-shell polymeric particles. The core of the particles comprises a hydrophobic polymer having an acid number less than 10. The shell of the particles comprises a hydrophilic polymer having an acid number of at least 70. The weight ratio of the core to the shell is at least 50:50 and up to and including 90:10. Such compositions can be used in various ink jet printing systems including drop on demand and continuous ink jet printing systems.
1. An aqueous ink jet ink composition comprising:
a visible or invisible colorant, and
a polymeric agent comprising core-shell polymeric particles,
wherein the core of the core-shell polymeric particles comprises a polyurethane having an acid number of less than 10, and the shell of the core-shell polymeric particles comprises a water-soluble or water-dispersible polyurethane having an acid number of at least 70, and the weight ratio of the core to the shell is at least 50:50 and up to and including 90:10.
2. The aqueous ink jet ink composition of claim 1 , wherein the core of the core-shell polymeric particles comprises a polyurethane having an acid number of 0 and up to and including 5, the shell of the core-shell polymeric particles comprises a water-soluble or water-dispersible polyurethane having an acid number of at least 100, and the weight ratio of the core to the shell is at least 50:50 and up to and including 70:30.
3. The aqueous ink jet ink composition of claim 1 , wherein the core has an acid number of less than 5.
4. The aqueous ink jet ink composition of claim 1 , wherein the shell has an acid number of at least 100 as provided by acidic groups.
5. The aqueous ink jet ink composition of claim 1 , wherein the colorant is a visible non-fluorescing colorant.
6. The aqueous ink jet ink composition of claim 1 , wherein the colorant is a visible or invisible fluorescing colorant.
7. The aqueous ink jet ink composition of claim 1 , wherein the polymeric agent is present in an amount of at least 0.1 weight % and up to and including 20 weight %.
8. The aqueous ink jet ink composition of claim 1 , further comprising a dispersing agent for the visible or invisible colorant.
9. The aqueous ink jet ink composition of claim 1 , further comprising a humectant.
10. An aqueous ink jet ink composition comprising:
a polymeric agent comprising core-shell polymeric particles that is present in an amount of at least 0.5 weight % and up to and including 10 weight %,
wherein the core of the core-shell polymeric particles comprises a polyurethane having an acid number of less than 10, and the shell of the core-shell polymeric particles comprises a water-soluble or water-dispersible polyurethane having an acid number of at least 80, and the weight ratio of the core to the shell is at least 50:50 and up to and including 90:10.