Chain of Custody Credit Accounting Protocols for Packaging Board Mills
Mill credit accounting requires dry fiber mass balance calculations, yield factor adjustments for coating mass, and strict rolling credit ledger management.
Mineral Coating Mass Offset
Coating Balance
Coating application adjustments rebalance pigment formulation mass and raw base stock grammage to achieve target finished sheet mass. Mill process controllers monitor mineral coating mass offset when adjusting doctor blade pressures and coater speed ratios on liquid coating lines. The parameter governs mineral pigment layer deposition on paperboard and graphic paper webs.
The scope excludes dry extrusions, wax impregnations and foil laminations.
Mass Compensation
Pigment formulations containing calcium carbonate and latex binders add dry mass to the base paper web during coating application. Base paper machines reduce fiber grammage when mineral coating mass increases to keep total finished basis weight within commercial order specifications. Online ash sensors and coat weight gauges feed continuous mass measurements to process control computers.
Automated control loops adjust metering blade loading to correct coater coat weight variations across the web width. Calculating mineral coating mass offset allows paper mills to balance raw fiber consumption against mineral binder costs without changing total sheet weight.
Surface Property
Pigment coating layers increase surface smoothness and opacity while modifying ink absorption rates during printing. Insufficient coat weight leads to fiber mottling, poor gloss and uneven ink absorption across printed surfaces. Excessive mineral coating reduces sheet stiffness and folding endurance in packaging applications.