Virgin Softwood Pulp Ratio Verification in Technical Packaging Papers
Verifying virgin softwood content in packaging paper relies on fiber morphology analysis, ISO chemical pulp identification, and trace chemical markers
ISO 16065
Standard Method
An international testing protocol governs the determination of fiber length in pulp samples using automated optical analysis. This protocol, designated as iso 16065, establishes uniform parameters for evaluating fiber distribution in both recycled and virgin pulps. It ensures that different laboratories can reproduce length measurements with high precision.
Paper manufacturers use this standard to monitor fiber quality and refining consistency.
Operational Procedure
Diluted pulp specimens are passed through a measuring cell where individual fibers are illuminated and analyzed by a digital sensor. The procedure under iso 16065 requires specific calibration steps to ensure that the instrument correctly identifies the ends of curved or bent fibers. It specifies how to calculate both arithmetic average length and weight weighted average length, which are used to assess the strength potential of the pulp.
By utilizing standardized flow rates and optical sensors, the test eliminates operator bias from the measurement process. The system counts thousands of fibers in a few minutes, providing a statistical distribution that manual microscopy cannot match.
Data Application
Sourcing teams evaluate pulp shipments against these standardized results to verify compliance with technical agreements. A shift in the weight weighted fiber length can indicate a change in wood chip sourcing or pulp mill operation. This information helps paper machine operators adjust the refining intensity to preserve fiber length while achieving the required sheet density.
Maintaining the average fiber length above a specified threshold is necessary to prevent sheet breaks on fast printing presses.