White pre-treatment composition

1. A white pre-treatment composition comprising a liquid vehicle, a polyvalent metal salt, a latex resin in the form of a dispersion of polymeric particles dispersed in an aqueous matrix and, at least, 8 wt % of a titanium dioxide particles dispersion.

2. The white pre-treatment composition according to claim 1 wherein said composition has a viscosity that is more than about 2000 cps.

3. The white pre-treatment composition according to claim 1 wherein said composition has a viscosity that is between about 3000 cps and about 10000 cps.

4. The white pre-treatment composition according to claim 1 wherein the titanium dioxide particles dispersion comprises polyether alkoxysilane dispersants.

5. The white pre-treatment composition according to claim 1 wherein the titanium dioxide particles have a mean diameter that is between about 50 to about 500 nm.

6. The white pre-treatment composition according to claim 1 wherein the titanium dioxide particles dispersion is present in an amount representing at least 8 wt % up to about 15 wt % of the total weight of the pre-treatment composition.

7. The white pre-treatment composition according to claim 1 wherein the polyvalent metal salt is selected from the group consisting of calcium chloride, calcium nitrate, magnesium nitrate, magnesium acetate and zinc acetate.

8. The white pre-treatment composition according to claim 1 wherein the polyvalent metal salt is calcium chloride or calcium nitrate.

9. The white pre-treatment composition according to claim 1 wherein the latex resin has an acid number of less than 20.

10. The white pre-treatment composition according to claim 1 wherein the latex resin is a polymer or a copolymer selected from the group consisting of acrylic polymers, vinyl-acrylic copolymers and acrylic-polyurethane copolymers.

11. The white pre-treatment composition according to claim 1 , wherein the white pre-treatment composition comprises at least about 40 wt % water.

12. An ink-set comprising:

a. a white pre-treatment composition containing a liquid vehicle, a polyvalent metal salt, a latex resin in the form of a dispersion of polymeric particles dispersed in an aqueous matrix and, at least, 8 wt % of a titanium dioxide particles dispersion;

b. and, at least, an ink composition comprising a liquid vehicle and a colorant.

13. The ink-set according to claim 12 wherein the titanium dioxide particles dispersion, in the white pre-treatment composition, comprises polyether alkoxysilane dispersants.

14. The ink-set according to claim 12 , wherein the white pre-treatment composition comprises at least about 40 wt % water.

15. A method for printing images onto a recording media, comprising:

a. applying a white pre-treatment composition onto a recording media, said pre-treatment composition comprising a liquid vehicle, a polyvalent metal salt, a latex resin in the form of a dispersion of polymeric particles dispersed in an aqueous matrix and, at least, 8 wt % of a titanium dioxide particles dispersion;

b. applying an ink composition, comprising a liquid vehicle and a colorant, over said white pre-treatment composition.

16. The method for printing images according to claim 15 wherein the white pre-treatment composition is applied onto the recording media using coating devices and wherein the ink composition is jetted onto said recording media via inkjet nozzles.

17. The method for printing images according to claim 15 wherein the recording media is a packaging recording substrate, a label or a label stock.

18. The method for printing images according to claim 15 , wherein the white pre-treatment composition comprises at least about 40 wt % water.