The Effect of a Sustainable Technology of Delignification and Tcf Bleaching on Physical Properties of Recovered Cardboard

Abstract Old Corrugated Containers (OCC), also known as waste corrugated cardboard, multilayer packaging and wrapping sacks are complex and heterogeneous materials composed of various sources of unbleached cellulose pulp derived from several raw material processes. However, OCC pulp have a high proportion of long fiber because are mainly manufactured from softwood pulp by the kraft process. OCC are the main category of recovered paper; however, due to their high lignin content, hornification and other problems resulting from the pulp to cardboard conversion processes, additives and pollutants, their physical properties decrease with each recycling which justifies evaluating various treatments with existing technologies to improve it. The objective of this work was to obtain improved unbleached and bleached old corrugated container (OCC) pulp more ecologically justifiable than wood for higher grade papers using sustainable processes evaluated in pilot scale tests OCC were collected from a landfill, cleaned, repulped, and treated with extended delignification with the alkaline soda process, obtaining a pulp with significant physical-mechanical improvements in relation to the original material, such as tensile strength, tearing resistance, bursting strength and folding endurance. The OCC soda pulp was bleached by a sequence totally free of chlorinated compounds (TCF), obtaining bleached pulp with optical and mechanical properties comparable to virgin pulps of annual plants such as bagasse but with improved drainage properties and lower processing costs. According to their properties, it is a competitive pulp obtained with existing technologies, available for use in various grades of printing and writing paper replacing totally or partially bleached wood pulp.