Manufacturing methods of printed corrugated cardboard
A manufacturing method of printed corrugated cardboard comprising the steps of: a) providing a paper liner board ( 23 ) with an ink receiving layer; and b) inkjet printing an image with one or more pigmented aqueous inkjet inks on the ink receiving layer using piezoelectric through-flow print heads ( 25 ) having nozzles with an outer nozzle surface NS smaller than 500 μm2; wherein the one or more pigmented aqueous inkjet inks contain water in an amount of A wt % defined by: wherein the wt % is based on the total weight of the aqueous inkjet ink; wherein sqrt(NS) represents the square root of the outer nozzle surface area NS; and wherein A wt %≥40 wt %.
1. A manufacturing method of printed corrugated cardboard comprising the steps of:
a) providing a paper liner board with an ink-receiving layer; and
b) inkjet printing an image with one or more pigmented aqueous inkjet inks on the ink receiving layer using piezoelectric through-flow print heads having nozzles with an outer nozzle surface area NS smaller than 500 μm 2 ;
wherein the one or more pigmented aqueous inkjet inks contain water in an amount of A wt % defined by Formula (I):
100 wt %−sqrt(NS)×3.8 wt %/μm≤ A wt %≤100 wt %−sqrt(NS)×2.2 wt %/μm Formula (I)
wherein the wt % is based on the total weight of the aqueous inkjet ink;
wherein sqrt(NS) represents the square root of the outer nozzle surface area NS;
wherein A wt %≥40 wt %; and
wherein the dry weight of the ink-receiving layer is less than 0.8 g/m 2 .
2. The manufacturing method of claim 1 , further comprising a step c) of laminating inkjet printed paper linerboard onto a fluted paperboard of a corrugated cardboard.
3. The manufacturing method of claim 1 , wherein the inkjet printing is performed according to a single pass printing process.
4. The manufacturing method of claim 1 , wherein the ink-receiving layer contains a polymer or copolymer based on polyvinylalcohol and a polyvalent metal salt.
5. The manufacturing method of claim 1 , including a step of applying a protective varnish layer on the inkjet printed image.
6. The manufacturing method of claim 1 , wherein the ink-receiving layer and/or the protective varnish layer are applied by flexographic printing.
7. The manufacturing method of claim 1 , wherein the outer nozzle surface area NS is smaller than 300 μm 2 .
8. The manufacturing method of claim 1 , wherein the one or more aqueous inkjet inks have a viscosity between 3.0 and 8.0 mPa·s at 32° C. at a shear rate of 1,000 s −1 .
9. The manufacturing method of claim 1 , wherein the paper liner board is provided in the form of a roll.
10. The manufacturing method of claim 1 , wherein the pigmented aqueous inkjet inks include:
a) a cyan aqueous inkjet ink containing a beta-copper phthalocyanine pigment;
b) a magenta or red aqueous inkjet ink containing a pigment selected from the group consisting of C.I. Pigment Red 57/1, C.I. Pigment Red 122, C.I. Pigment Violet 19, and mixed crystals thereof;
c) a yellow aqueous inkjet ink containing a pigment selected from C.I. Pigment Yellow 74, C.I. Pigment Yellow 138, C.I. Pigment Yellow 151, and mixed crystals thereof; and
d) a black aqueous inkjet ink containing a carbon black pigment.
11. The manufacturing method of claim 1 , wherein the paper liner board has a white colour.
12. The manufacturing method of claim 1 , wherein the printed corrugated cardboard is a single wall or double corrugated cardboard.