Method of making wet embossed paperboard
A process for manufacturing an embossed paperboard comprising the steps of: forming a wet mat including more than 60 wt % of cellulose fibers; pressure molding, with at least one embossing roll, the wet mat having 20 to 70 wt % solid to create a nested surface texture thereon; and drying the embossed wet mat to obtain the embossed paperboard with a grammage ranging between 125 and 1500 grams per square meter.
1. A process for manufacturing an embossed paperboard comprising the steps of:
forming a wet mat including more than 60 wt % of cellulose fibers;
pressure molding, with at least one unheated embossing roll by applying a pressure greater than 200 pounds per linear inch (PLI), the wet mat having 20 to 70 wt % solid to create a nested surface texture thereon; and
drying the embossed wet mat to obtain the embossed paperboard with a grammage ranging between 250 and 1500 grams per square meter.
2. A process as claimed in claim 1 , wherein forming the wet mat comprises superposing 2 to 12 paper plies.
3. A process as claimed in claim 1 , wherein forming the wet mat comprises superposing 7 to 9 paper plies.
4. A process as claimed in claim 1 , wherein the embossed paperboard obtained during the step of drying has a grammage ranging between 250 and 1200 grams per square meter.
5. A process as claimed in claim 1 , wherein the embossed paperboard obtained during the step of drying has a grammage ranging between 250 and 900 grams per square meter.
6. A process as claimed in claim 1 , wherein the embossed paperboard obtained during the step of drying has a grammage ranging between 300 and 500 grams per square meter.
7. A process as claimed in claim 1 , wherein the pressure molding step comprises applying a pressure less than 600 pounds per linear inch (PLI).
8. A process as claimed in claim 1 wherein the pressure molding step comprises applying a pressure ranging between 200 and 400 pounds per linear inch (PLI).
9. A process as claimed in claim 1 , wherein the pressure molding step is carried out with two unheated embossing rolls having spaced-apart knobs in meshing engagement, the two embossing rolls being synchronously rotated and being spaced apart from one another by more than 20 mils.
10. A process as claimed in claim 1 , comprising decelerating the wet mat for carrying the pressure molding step.
11. A process as claimed in claim 10 , comprising accelerating the wet mat for carrying the drying step.
12. A process as claimed in claim 1 , comprising withdrawing excess water while carrying the pressure molding step.
13. A process as claimed in claim 1 , wherein the solid content of the wet mat ranges between 35 and 55 wt % during the pressure molding step.
14. A process as claimed in claim 1 , wherein the wet mat comprises more than 80 wt % of cellulose fibers.
15. A process as claimed in claim 1 , wherein the wet mat comprises less than 30 wt % of inorganic fillers.
16. A process as claimed in claim 1 , wherein the cellulose fibers of the wet mat comprises more than 60 wt % of recycled fibers.
17. A process as claimed in claim 1 , wherein the embossed paperboard has a specific volume density ranging between 1 and 6 cubic centimeter per gram.
18. A process as claimed in claim 1 , wherein the embossed paperboard has a tensile strength ranging between 100 and 700 Newtons per inch.
19. A process as claimed in claim 1 , wherein the embossed paperboard has a thickness ranging between 250 and 5 000 micrometers.
20. A process as claimed in claim 1 , wherein the embossed paperboard has a moisture content below 15 wt %.
21. A process as claimed in claim 1 , wherein embossed paperboard has a grammage ranging between 250 and 900 grams per square meter.