ABSTRACT Recycling paper (secondary fiber) for different recycled pulp grades has been seen as the solution for the lack of forest products for pulp and paper production. However on secondary fiber, both reversible and irreversible changes as hornification, loss in flexibility, swelling properties, conformability and lower strength and bonding between fibers take place in progressive and repeated recycling which results in a weaker, lower grade of paper. This study carried out a review of the state of the art of technical constraints and limiting factors of recycling and analyzes the possibility to improve the mechanical and optical properties of old corrugated container (OCC) pulps, through a stage of alkaline delignification by the soda chemical process, and subsequent elementary chlorine free bleaching (ECF). OCC soda pulp was conducted to substitute unbleached and bleached kraft pulp (UKP) for the manufacture of bagasse paper. The OCC soda pulp/bagasse pulp mixtures were evaluated according to the international TAPPI test of mechanical resistance and optical properties. Results showed that the OCC soda pulps and bagasse pulp mixtures were upgrading on tear, burst, tensile and folding minimizing the negative effects of recycling on drainability. OCC means an alternative resource of fiber to obtain unbleached pulp or bleached pulps which justify the use of the delignification stage and support this process to produce an important source of bleached fibers for the manufacturing of various types of non-wood paper and linerboard.
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