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AssigneeCartons St-Laurent, Inc./St. Laurent Paperboard, Inc.
InventorsSerge Koutitonsky, Stephane Rousseau
Estimating the term…
A method for making a surface coated or impregnated paper or paperboard by applying an aqueous additive dispersion to the wet web between the press and drying sections of a conventional paper or paperboard making machine. The aqueous additive dispersion is pre-metered onto a transfer roll and is applied to the wet web at a pressure nip between the transfer roll and a back-up roll. High solids content dispersions can be applied at high web speeds without tearing the web. The use of a high solids content aqueous dispersion having a solids content substantially equal to the solids content of the wet web at the point of application permits the method to be performed without increasing the drying load and therefore at an unreduced speed. The method contemplates the use of a hydrophillic transfer roll running in a direction opposite to the web, permitting a saturant to be impregnated into the web, and has particular application to the production of containerboard treated with a lignosulfonate saturant to improve strength and surface character.
A method of making a surface coated or saturated paper or paperboard comprising the steps of forming a wet web of paper or paperboard, subjecting said web to at least one pressing operation, subjecting at least one said of said web to a liquid application operation and drying said web, said liquid application operation being carried out after all pressing operations and before any drying operations, said liquid application operation comprising the steps of metering a smooth uniform film of an aqueous additive dispersion onto a rotating transfer roll having a hydrophilic metal liquid receptive surface rotating, rotating at web direction and substantially at web speed a smooth surfaced resilient back-up roll in pressure-nip relationship with said transfer roll and contacting said metered film on said rotating surface of said transfer roll with one side of said web at the pressure nip, said aqueous additive dispersion having a moisture content that is approximately equal to or less than the moisture content of the wet web after all pressing operations.
Dependencies are inferred from the claim text.