Method to debond paper on a paper machine

Abstract

Disclosed is a method of making a soft, strong cellulosic tissue sheet comprising the steps of forming a web of cellulosic fibers on a forming wire, thereafter treating the exposed surface of the web with a treatment composition comprising a chemical debonding agent, subjecting the opposing surface of the web to vacuum suction whereby the chemical debonding agent is distributed substantially through the entire thickness of the web, and through-air drying the web. The method allows grade changes to be made much more rapidly and with less waste than when adding debonder at the wet end of the paper making process.

1 . A method for making a soft, strong cellulosic tissue sheet comprising the steps of: 
 forming a web of cellulosic fibers on a forming wire,    thereafter, treating the exposed surface of the web with a treatment composition comprising a chemical debonding agent,    subjecting the opposing surface of the web to vacuum suction whereby the chemical debonding agent is distributed substantially through the entire thickness of the web, and    through-air drying the web.    
   
   
       2 . The method of  claim 1  wherein the vacuum suction is applied without removing a substantial quantity of the chemical debonding agent from the web.  
   
   
       3 . The method of  claim 1  wherein the chemical debonding agent comprises an oleyl imidazolinium compound.  
   
   
       4 . The method of  claim 1  further comprising the step of combining the tissue sheet with additional tissue layers to form a layered tissue product.  
   
   
       5 . The method of  claim 1 , wherein the treatment composition is applied to the web when the web has a consistency of greater than about 10%.  
   
   
       6 . The method of  claim 1 , wherein the treatment composition is applied to the web when the web has a consistency of greater than about 15% and less than about 80%.  
   
   
       7 . The method of  claim 1 , wherein the treatment composition is applied to the web when the web has a consistency of greater than about 15% and less than about 30%.  
   
   
       8 . The method of  claim 1 , wherein the treatment composition is applied to the web in between a rush transfer operation and the through-air drying operation.  
   
   
       9 . The method of  claim 1 , wherein the treatment composition is applied to the web in between a first through-air drying operation and a second through-air drying operation.  
   
   
       10 . The method of  claim 1 , wherein the treatment composition further comprises a lubricant and a surfactant.  
   
   
       11 . The method of  claim 10 , wherein the lubricant comprises a lanolin derivative.  
   
   
       12 . The method of  claim 10 , wherein the surfactant comprises a polyethylene glycol ester, a polypropylene glycol ester, or mixtures thereof.  
   
   
       13 . A tissue product made according to the method of  claim 1 , the tissue product comprising: (a) cellulosic fibers, and (b) the chemical debonding agent.  
   
   
       14 . A tissue product made according to the method of  claim 1 , the tissue product comprising: a paper web comprising cellulosic fibers; and the chemical debonding agent topically applied to the paper web, the chemical debonding agent being present in the web in an amount of from about 0.01% to about 10% by weight.  
   
   
       15 . The tissue product of  claim 14 , wherein the debonding agent being applied to the paper web while the web has a consistency of less than about 80%.  
   
   
       16 . The tissue product of  claim 14 , wherein the debonding agent comprises an oleyl imidazolinium compound.  
   
   
       17 . The tissue product of  claim 14 , wherein the debonding agent comprises an imidazoline quaternary ammonium salt.  
   
   
       18 . The tissue product of  claim 14 , wherein the tissue product is multi-layered.  
   
   
       19 . The tissue product of  claim 14 , wherein the tissue product includes a middle layer positioned in between a first outer layer and a second outer layer of fibers, the first and second outer layers comprising hardwood fibers, the middle layer comprising softwood fibers.  
   
   
       20 . In a method for making a soft, strong cellulosic tissue sheet wherein a web of cellulosic fibers is formed on a forming wire and thereafter through-air dried, the improvement comprising treating one face surface of the web with a dilute aqueous solution of a chemical debonding agent in an amount effective to soften substantially the entire thickness of the sheet and thereafter, prior to the sheet being through-air dried, subjecting the web to vacuum suction whereby, after through-air drying of the sheet, the chemical debonding agent is distributed at a substantially uniform concentration through substantially the entire thickness of the sheet.