Dynamic Shear Modulus Degradation Limits in High Speed Recyclable UV Resin Formulations
Dynamic shear degradation limits UV resin velocity at 280 m/min to prevent oligomer scission, balancing resin costs against full EPR fee savings.
Deinking Flotation Efficiency
Separation Measure
Recovery rates for high-quality recycled pulp depend on the removal of hydrophobic ink particles from fiber slurries. Determining deinking flotation efficiency allows mill operators to assess how effectively a recycling line cleans the incoming secondary fibers. This calculation measures the ratio of ink concentration before and after the flotation cell.
High recovery rates prevent brightness loss and reduce the frequency of aesthetic defects in the finished sheet.
Hydrodynamic Action
Flotation cells rely on the attachment of ink to rising air bubbles. Finely dispersed air is injected into the pulp slurry, where hydrophobic ink particles collide with the bubbles and rise to the surface as foam. Surfactants added to the pulper modify the surface tension to encourage this attachment while keeping the hydrophilic cellulose fibers suspended in the water phase.
A vacuum system skims off the foam to complete the extraction.
Process Optimization
Maximizing this separation rate involves controlling bubble size and fiber consistency. Large bubbles rise too quickly to collect small ink particles, while extremely small bubbles fail to carry larger toner fragments from digital prints. Slurry consistency must remain below one percent to prevent fiber entanglement from blocking the bubble ascent.
If the pulp flows through the cell too rapidly, the dwell time becomes insufficient for the bubbles to collect the ink, leading to poor final brightness and higher chemical consumption downstream. Adjusting the air-to-liquid ratio and monitoring the reject stream flow rate ensures that the system removes the maximum amount of ink with minimal fiber loss.