Aqueous Dispersion Coating Chemistry Optimization for High Yield Mechanical Hydrapulping
Optimizing carboxylated acrylic dispersion coatings enables complete mechanical pulp fiber liberation while keeping screen rejects below one percent.
Papermaking White Water
Filtrate Composition
Fluid collected from the wire section of a paper machine contains suspended fibers, fines, fillers and various chemical additives. This papermaking white water functions as a complex mixture requiring careful management to maintain machine runnability and product quality. Mills reuse this fluid in showers or stock dilution to maximize water efficiency and retain fiber yield.
Constant monitoring of suspended solids prevents scaling or slime growth on mechanical components during continuous production runs.
Solid Management
Particles found within the recirculating stream dictate the frequency of purging or chemical treatment. High levels of fines reduce drainage rates through the forming fabric and influence the opacity or strength of the final sheet. Operators adjust retention aids to force these smaller components onto the cellulose mat rather than allowing the materials to accumulate in the circulation system.
Excessive buildup of colloidal matter interferes with the intended surface characteristics of the paper.
Systemic Balance
Precise control over dissolved ions and electrolytic conductivity protects against the degradation of functional additives like sizing agents or optical brighteners. Fluctuations in the pH or temperature of the recirculated medium alter the effectiveness of wet-end chemistry and result in inconsistent sheet formation across varying grades. Mills stabilize these parameters to ensure that the chemical environment supports uniform deposition of fibers onto the screen.
Consistency in the drainage characteristics of the loop provides the necessary stability for reliable paper sheet structure.