Testing Standard
Standardized testing protocol calculates the concentration of macrostickies in a pulp sample through a process of screening and image analysis. Compliance with tappi t 277 allows mills to benchmark the cleanliness of their recycled fibre streams against industry standards. It provides a consistent framework for measuring contaminants that are larger than 0.10 millimetres in diameter.
Analytical Procedure
A known dry weight of pulp is diluted and passed through a vibrating screen equipped with narrow slots to capture the tacky contaminants. These particles are then transferred to a plastic film or filter paper and treated with black toner or specific dyes to enhance their visibility. The final measurement uses a scanner and specialized software to calculate the total area and the number of particles present in the sample.
Production Utility
This metric helps mill managers decide whether to increase the intensity of the cleaning and screening stages or to reject a specific lot of recovered paper. High levels of stickies detected by this method correlate directly with an increased risk of breaks on the paper machine or defects in the final printed product. Because the test focuses on macro contaminants it does not account for the dissolved or colloidal substances that might precipitate later in the process.
