Photoinitiator Migration Limits in Food Contact Print Finishes
Photoinitiator migration limits demand complete photopolymer conversion or functional containment to keep extractable residues below 10 parts per billion.
Microcure Radiometer
Measurement Instrument
Miniature sensor designed to measure the ultraviolet energy delivered to a substrate surface during high-speed printing or coating operations monitors the efficiency of curing lamps. This compact device, known as a microcure radiometer, is passed directly through the curing chamber on the moving web. It records the peak irradiance and the total UV dose received by the printed paperboard.
This measurement ensures that the ink receives sufficient energy to cure fully.
Radiometric Calibration
Collecting real-time exposure data helps press operators detect lamp degradation or dirty reflectors before uncured ink leads to production defects. The radiometer is built to withstand the intense heat of the UV lamps while maintaining high accuracy. This small footprint allows it to fit into tight spaces where larger instruments cannot go.
The resulting energy profile is essential for maintaining process consistency.
Process Validation
Using this diagnostic tool is an essential step in validating that a UV-curing press is operating within the parameters specified by the ink manufacturer. If the radiometer indicates that the UV dose has fallen below the required threshold, the operator can increase the lamp power or slow down the press to compensate. This prevents the production of cartons with uncured ink, which could otherwise migrate and cause odor problems in the packaging.
Regular monitoring with the radiometer thus provides a clear audit trail for quality control. It ensures that every batch of paperboard is cured to the same standard.