EFFECT OF DRY DEFIBRATION OF RECOVERED PAPER ON MULTILAYER CARDBOARD PROPERTIES

The article focuses on the relevant for the pulp and paper industry in the direction of reduction of energy consumption for the production of cardboard from recovered paper with the preservation of its mechanical parameters. The reduction cost is due to the partial replacement of the technology of traditional conventional preparation of the recovered paper with dry defibration. The dry defibration method affects the structural, mechanical and deformation properties of the cardboard. The purpose of the work is to obtain dependencies, listed characteristics on recovered paper content prepared by dry method. In order to maintain the mechanical and deformation properties of the cardboard when adding dry-defibrated fibers, it is necessary to correctly distribute them in the test liner layers and to set the stage of supply of dry-defibrated recovered paper into the process flow. To this end, various applications of the dry recovered paper preparation technique were experimentally analyzed, fed to and ground in an aqueous medium, and dry fibers were used to form a two-layer and three-layer test-liner cardboard. The maximum content of fibers prepared by the dry method to obtain a multilayer test-liner was 50% by weight of the cardboard, even though the main mechanical parameters, including tensile strength, bending stiffness, and short-span compression strength (SCT), changed slightly. Established optimal composition of cardboard, allowed using the results of experimental studies for industrial development. The article also provides a technical and economic estimation of different ways of dry defibration technology.