Paper for inkjet recording
The present invention concerns a print medium for inkjet printing and a method of producing such a print medium. In particular, the present invention is directed to a print medium comprising a base layer having a first side and a reverse side, an absorptive layer being in contact with the first side of the base layer, and a topcoat being in contact with the absorptive layer.
1. A print medium comprising:
a) a base layer having a first side and a reverse side;
b) an absorptive layer being in contact with the first side of the base layer, wherein the adsorptive layer comprises a pigment; and
c) a topcoat being in contact with the absorptive layer, wherein the topcoat has a permeability of greater than 5.0×10 −18 m 2 , and comprises a pigment having a d 50 value in a range from 0.01 to 1.0 μm.
2. The print medium of claim 1 , wherein the base layer is a wood free paper or a wood containing paper.
3. The print medium of claim 2 , having a basis weight from 30 to 300 g/m 2 .
4. The print medium of claim 1 , wherein the absorptive layer has an absorption rate from 1×10 −5 ms −0.5 to 1×10 −3 ms −0.5 and/or a volume uptake from 30 to 95% by volume relative to the total volume of the absorptive layer.
5. The print medium of claim 1 , wherein the pigment of the absorptive layer, when in the form of a compacted bed, has an absorption rate from 1×10 −5 ms −0.5 to 1×10 −3 ms −0.5 and/or a volume uptake from 35 to 95% by volume relative to the total volume of the pigment.
6. The print medium of claim 1 , wherein the pigment of the absorptive layer has a specific surface area of greater than 25 m 2 /g.
7. The print medium of claim 1 , wherein the pigment of the absorptive layer has a specific surface area of from 25 to 100 m 2 /g.
8. The print medium of claim 1 , wherein the pigment of the absorptive layer has a specific surface area of from 30 to 50 m 2 /g.
9. The print medium of claim 1 , wherein the pigment of the absorptive layer has a specific surface area of greater than 25 m 2 /g, a d 50 value from 0.3 to 3 μm and a porosity, when in form of a compacted bed, of greater or equal to 35%.
10. The print medium of claim 1 , wherein the pigment of the absorptive layer is a calcium carbonate, a plastic pigment, a polystyrene-based plastic pigment, titanium dioxide, dolomite, calcined clay, or any mixture thereof, or a mixture of one or more of calcium carbonate, titanium dioxide, dolomite, or calcined clay with one or more of talc, non-calcined clay or bentonite.
11. The print medium of claim 1 , wherein the pigment of the absorptive layer is a calcium carbonate.
12. The print medium of claim 1 , wherein the pigment of the absorptive layer is a modified calcium carbonate and/or a precipitated calcium carbonate.
13. The print medium of claim 11 , wherein the calcium carbonate is in acicular, prismatic, spheral, or rhombohedral form or any combination thereof.
14. The print medium of claim 1 , wherein the absorptive layer further comprises a binder in an amount of 1 to 50 wt.-% based on the total weight of the pigment.
15. The print medium of claim 14 , wherein the binder is starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate latex, or polyvinyl acetate latex or any mixture thereof.
16. The print medium of claim 1 , wherein the absorptive layer has a coat weight in a range from 3 to 50 g/m 2 .
17. The print medium of claim 1 , wherein the absorptive layer has a coat weight in a range from 3 to 40 g/m 2 .
18. The print medium of claim 1 , wherein the absorptive layer has a coat weight in a range from 6 to 20 g/m 2 .
19. The print medium of claim 1 , wherein the pigment of the topcoat is a calcium carbonate, a plastic pigment, a polystyrene-based plastic pigment, titanium dioxide, dolomite, calcined clay, or any mixture thereof, or a mixture of one or more of calcium carbonate, titanium dioxide, dolomite, or calcined clay with one or more of talc, non-calcined clay or bentonite.
20. The print medium of claim 1 , wherein the pigment of the topcoat is a calcium carbonate.
21. The print medium of claim 1 , wherein the pigment of the absorptive layer comprises ground calcium carbonate and/or a precipitated calcium carbonate.
22. The print medium of claim 1 , wherein the topcoat further contains a binder in an amount of 0.5 to 50 wt.-% based on the total weight of the pigment.
23. The print medium of claim 22 , wherein the binder is selected from starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate latex, or polyvinyl acetate latex or any mixture thereof.
24. The print medium of claim 1 , wherein the topcoat further comprises a rheology modifier in an amount of less than 1 wt.-% based on the total weight of the pigment.
25. The print medium of claim 1 , wherein the topcoat has a coat weight in a range from 1 to 50 g/m 2 .
26. The print medium of claim 1 , wherein the topcoat has a coat weight in a range from 3 to 40 g/m 2 .
27. The print medium of claim 1 , wherein the topcoat has a coat weight in a range from 6 to 20 g/m 2 .
28. The print medium of claim 1 , wherein the print medium further comprises a second absorptive layer being in contact with the reverse side of the base layer, and a second topcoat being in contact with the second absorptive layer.