Aqueous ink-jet inks for improved adhesion to print substrates

1. An aqueous ink-jet ink for printing on a print substrate, comprising an aqueous vehicle, a colorant, a first organic co-solvent and a second organic co-solvent, wherein:

i) said aqueous vehicle contains water in an amount greater than 20% of the total weight of the ink;

ii) said first organic co-solvent has a solubility of less than 4 g per 100 g of water and is used at an amount greater than its solubility in water at ambient temperature and pressure, and said first organic co-solvent is one or more members selected from the group consisting of 1-dodecanol, 1-octanol, 1-hexanol, 1-pentanol and neopentyl alcohol;

iii) said second organic co-solvent has a solubility of greater than 5 g per 100 g of water and is used at an amount sufficient to dissolve said first organic co-solvent in water at ambient temperature and pressure, and said second organic co-solvent is tetraethylene glycol dimethyl ether or 1,6-hexanediol, or mixture thereof;

iv) said print substrate is selected from the group consisting of textile, vinyl and offset media; and

v) said colorant is a carbon black or a self-dispersed pigment.

2. The ink of claim 1 wherein said ink-jet ink further comprises a dispersant to disperse said colorant.

3. The ink of claim 2 , wherein said dispersant is an acrylic polymer.

4. The ink of claim 2 , wherein said dispersant is polyurethane.

5. The ink of claim 2 , wherein said inkjet ink further comprises a cross-linking agent to cross-link with said dispersant.

6. The ink of claim 1 , wherein said colorant is encapsulated by a polymer.

7. The ink of claim 1 , herein said aqueous inkjet ink further comprises a binder.

8. The ink of claim 1 , wherein said print substrate is vinyl.

9. The ink of claim 1 , wherein said print substrate is textiles.

10. The ink of claim 1 , wherein said print substrate is offset media.

11. An aqueous inkjet ink consisting of an aqueous vehicle, a colorant, a first organic co-solvent and a second organic co-solvent, wherein said colorant is encapsulated by a polymer, and wherein:

i) said aqueous vehicle contains water in an amount greater than 20% of the total weight of the ink;

ii) said first organic co-solvent has a solubility of less than 4 g per 100 g of water and is used at an amount greater than its solubility in water at ambient temperature and pressure, and said first organic co-solvent is one or more members selected from the group consisting of 1-dodecanol, 1-octanol, 1-hexanol, 1-pentanol and neopentyl alcohol;

iii) said second organic co-solvent has a solubility of greater than 5 g per 100 g of water and is used at an amount sufficient to dissolve said first organic co-solvent in water at ambient temperature and pressure, and said second organic co-solvent is tetraethylene glycol dimethyl ether or 1,6-hexanediol, or mixture thereof;

iv) said print substrate is selected from the group consisting of textile, vinyl and offset media; and

v) said colorant is a carbon black pigment.

12. An aqueous ink-jet ink for printing on a print substrate consisting of an aqueous vehicle, a colorant, a first organic co-solvent, a second organic co-solvent, a dispersant and a cross-linking agent to cross-link with said dispersant, wherein:

i) said aqueous vehicle contains water in an amount greater than 20% of the total weight of the ink;

ii) said first organic co-solvent has a solubility of less than 4 g per 100 g of water and is used at an amount greater than its solubility in water at ambient temperature and pressure;

iii) said second organic co-solvent has a solubility of greater than 5 g per 100 g of water and is used at an amount sufficient to dissolve said first organic co-solvent in water at ambient temperature and pressure, and said second organic co-solvent is tetraethylene glycol dimethyl ether or 1,6-hexanediol, or mixture thereof;

iv) said print substrate is selected from the group consisting of textile, vinyl and offset media; and

v) said colorant is a carbon black or a self-dispersed pigment.

13. The ink of claim 12 , wherein said first organic co-solvent is one or more members selected from the group consisting of 1-dodecanol, 1-octanol, 1-hexanol, 1-pentanol and neopentyl alcohol.

14. A method of ink-jet printing onto a substrate comprising, in any workable order, the steps of:

a) providing an ink-jet printer that is responsive to digital data signals;

b) loading the printer with a substrate to be printed;

c) loading the printer with an aqueous ink-jet ink comprising an aqueous vehicle, a colorant, a first organic co-solvent and a second organic co-solvent, wherein:

i) said aqueous vehicle contains water in an amount greater than 20% of the total weight of the ink;

ii) said first organic co-solvent has a solubility of less than 4 g per 100 g of water and is used at an amount greater than its solubility in water at ambient temperature and pressure;

iii) said second organic co-solvent has a solubility of greater than 5 g per 100 g of water and is used at an amount sufficient to dissolve said first organic co-solvent in water at ambient temperature and pressure, and said second organic co-solvent is tetraethylene glycol dimethyl ether or 1,6-hexanediol, or mixture thereof;

iv) said print substrate is selected from the group consisting of textile, vinyl and offset media; and

v) said colorant is a carbon black or a self-dispersed pigment.

15. The ink of claim 1 , wherein said second organic co-solvent is tetraethylene glycol dimethyl ether.

16. The ink of claim 1 , wherein said second organic co-solvent is 1,6-hexanediol.