Mechanical Yield
Chemical processing sequences retain the majority of wood raw material mass through the removal of specific non-fibrous binders like lignin. High yield pulp retains a significant portion of these components, resulting in a yield often exceeding eighty percent of the original wood mass. This mechanical process contrasts with chemical cooking cycles where yield values drop closer to fifty percent due to the dissolution of hemicelluloses and lignin.
The structural integrity and opacity of the final sheet depend directly on the high content of retained lignin within the fibres.
Fibre Density
Rigid and bulky characteristics develop when these fibres undergo processing without complete delignification. Short fibre fractions typically correlate with lower internal bond strength compared to their chemical counterparts. Manufacturers select this material for applications requiring high volume and stiffness, such as newsprint or specific board layers where physical bulk provides the desired caliper.
The presence of lignin leads to inevitable yellowing over time when exposed to ultraviolet radiation.
Production Efficiency
Energy requirements for the mechanical grinding stage replace the chemical costs associated with heavy bleaching and cooking agents. Efficient conversion cycles allow mills to maximize the output of every ton of timber by preserving the natural components of the plant. A primary trade off occurs between the increased opacity of the sheet and the reduced longevity of the paper strength.
Environmental impacts shift away from chemical effluent management toward high electrical consumption per produced unit.
