| abstract |
The invention relates to the field of pulp and paper industry and improves the quality of cardboard. Paper pulp for the surface, lining of the middle and lower layers serves on four threads. For the preparation of pulp on the surface layer, bleached sulphate pulp is used, for lining - MS-1, MS-2 and MS-3 waste paper, for the middle layer - MS-2, MS-3, MS-6, MS-1O, and for bottom layer - 80-95% of MS-4, MS-5, MS-6 waste paper and 5-20% of newspaper waste paper. After dissolution and purification, the waste mass is subjected to thermal dispersion treatment at 95 C. Disperse the paper pulp of all the flows is produced on MDS-24 mills. Then the fibers for the outer layers are glued in the mass with rosin glue. The layers of cardboard are formed separately on vacuum-forming cylinders, then they are joined, pressed and dried. The molding of the cardboard layers is carried out at a mass concentration,%: the surface layer is 0.4-0.5, the lining layer is 0.8-1.2, the middle layer is 1.0-1.5, and the bottom layer is 0.6-0.8. 1 tab. (L |