Pressurized high-consistency refining (PHCR) of kraft pulps has been a unique way to produce sheets with high air permeability and good tensile energy absorption (TEA). Fibers treated by PHCR are more curled and appeared to be more micro-compressed. B...
Pressurized high-consistency refining (PHCR) of kraft pulps has been a unique way to produce sheets with high air permeability and good tensile energy absorption (TEA). Fibers treated by PHCR are more curled and appeared to be more micro-compressed. Bruising action originated from screw feeding of high consistency stock to refiner was revealed as the main reason for the morphological change of fibers. Instead of screw feeder, kneader was used in this study. It results in increased stretch, a favorable combination of TEA and Gurley air resistance. In addition, highly air permeable kraft sack paper with reduced freeness can be produced by the addition of PVAm as a dry strength agent.