Methods of forming paper products and paper products formed through the methods

Abstract

Methods of forming paper products are provided herein. A method comprises providing an aqueous suspension of cellulosic fibers; diluting the aqueous suspension with water to form a diluted aqueous suspension having a solids content from about 0.3 wt % to about 1.8 wt %, based on a total weight of the diluted aqueous suspension; subjecting the diluted aqueous suspension to a high shear operation; adding an aqueous composition comprising an adduct formed from the reaction of glyoxal and a polyvinylamide prepolymer to the diluted aqueous suspension; forming the diluted aqueous suspension into a sheet; and drying the sheet. The aqueous composition is added after the diluted aqueous suspension is subjected to the high shear operation and before the diluted aqueous suspension is passed to a headbox. The method is free of any high shear operation after the aqueous composition is added and before the diluted aqueous suspension is passed to the headbox.

What is claimed is: 
     
         1 . A method of forming a paper product, the method comprising the steps of:
 providing an aqueous suspension of cellulosic fibers;   diluting the aqueous suspension with water to form a diluted aqueous suspension having a solids content of from about 0.3 wt % to about 1.8 wt %, based on a total weight of the diluted aqueous suspension;   subjecting the diluted aqueous suspension to a high shear operation;   adding an aqueous composition to the diluted aqueous suspension, wherein the aqueous composition comprises an adduct formed from the reaction of glyoxal and a polyvinylamide prepolymer;   forming the diluted aqueous suspension into a sheet by a headbox; and   drying the sheet to form the paper product;
 wherein the aqueous composition is added to the diluted aqueous suspension after the diluted aqueous suspension is subjected to the high shear operation and before the diluted aqueous suspension is passed to the headbox; and 
   wherein the method is free of any high shear operation after the aqueous composition is added and before the diluted aqueous suspension is passed to the headbox.   
     
     
         2 . The method of  claim 1 , wherein the adduct has a weight average molecular weight of from about 70,000 Daltons to about 500 million Daltons, as measured using gel permeation chromatography. 
     
     
         3 . The method of  claim 1 , wherein the prepolymer has a weight average molecular weight of from about 50,000 Daltons to about 5 million Daltons, as measured using gel permeation chromatography. 
     
     
         4 . The method of  claim 1 , wherein subjecting the diluted aqueous suspension to a high shear operation comprises subjecting the diluted aqueous suspension to a fan pump, a high pressure screen, or a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein subjecting the diluted aqueous suspension to a high shear operation comprises subjecting the diluted aqueous suspension to at least two high shear operations. 
     
     
         6 . The method of  claim 1 , wherein the aqueous composition is added to the diluted aqueous suspension such that the ratio of the flow velocity of the aqueous composition to the flow velocity of the diluted aqueous suspension is from about 1:1 to about 10:1. 
     
     
         7 . The method of  claim 1 , wherein, upon addition of the aqueous composition to the diluted aqueous suspension, the adduct is present in the aqueous composition in an amount of from about 0.02 wt % to about 5.0 wt % active solids. 
     
     
         8 . The method of  claim 1 , wherein the adduct is present in the diluted aqueous suspension in an amount such that from about 0.25 kilograms to about 10 kilograms of adduct, based on active solids, is present for every metric ton of solids present in the diluted aqueous suspension. 
     
     
         9 . The method of  claim 1 , wherein the aqueous composition is added through a nozzle, wherein the flow of the aqueous composition out of the nozzle is turbulent flow. 
     
     
         10 . The method of  claim 1 , wherein the aqueous composition further comprises an additive different from the adduct. 
     
     
         11 . The method of  claim 1 , further comprising adding to the diluted aqueous suspension a second composition different from the aqueous composition comprising the adduct. 
     
     
         12 . The method of  claim 11 , wherein the second composition comprises an additive different from the adduct. 
     
     
         13 . The method of  claim 1 , further comprising preparing the aqueous composition comprising the adduct by reacting a substantially aqueous reaction mixture of the polyvinylamide prepolymer and the glyoxal, wherein the concentration of the polyvinylamide prepolymer is below, equal to or no more than 1% above a Critical Concentration, and the Critical Concentration is defined as the concentration of the polyvinylamide prepolymer above which Critical Concentration the viscosity increases for the reaction mixture resulting from the forward progress of the adduct formation, and below which Critical Concentration, the viscosity decreases for the reaction mixture resulting from the forward progress of adduct formation. 
     
     
         14 . The method of  claim 13 , wherein the Critical Concentration is from about 1.0 wt % to about 3.0 wt % of the polyvinylamide prepolymer, based on a total weight of the reaction mixture. 
     
     
         15 . The method of  claim 13 , wherein the polyvinylamide prepolymer is present in the reaction mixture in an amount of less than about 4 wt %, based on a total weight of the reaction mixture, at the onset of the reaction. 
     
     
         16 . The method of  claim 13 , wherein the solids content of the aqueous composition is no more than about 2.5%. 
     
     
         17 . The method of  claim 1 , wherein the polyvinylamide prepolymer is a homopolymer or copolymer formed from (meth)acrylamide or a substituted (meth)acrylamide. 
     
     
         18 . The paper product formed through the method of  claim 1 . 
     
     
         19 . The paper product of  claim 18 , having a dry strength, as measured by the Ring Crush Test in accordance the standard method TAPPI/ANSI T 822 om-22, that is equal to or greater than a comparative paper product formed by a process comprising adding the aqueous composition to the aqueous suspension before diluting the aqueous suspension and before subjecting the aqueous suspension to the high shear operation. 
     
     
         20 . The paper product of  claim 18 , having a dry strength, as measured by the Mullen Burst Test in accordance with the standard method TAPPI/ANSI T 403 om-22, that is equal to or greater than a comparative paper product formed by a process comprising adding the aqueous composition to the aqueous suspension before diluting the aqueous suspension and before subjecting the aqueous suspension to the high shear operation.