Method for treating secondary fiber to achieve wet strength while retaining repulpability

Abstract

A method for treating secondary fiber to achieve wet strength while retaining repulpability is provided. In an embodiment, the method involves supplying a first line of secondary fiber which represents a total supply of secondary fiber. The method has a further step of removing a portion of the total supply of secondary fiber in the first line and transporting the portion into a second line. The second line is treated with a cationic resin treatment. A third line supplies virgin fiber. The third line and the first line are combined. Next, the treated secondary fiber in the second line is combined with the mixed contents of the first line and third line. Separation of the virgin fiber line from the secondary fiber line at initial stages of the process lowers cationic demand for the system, and reduces an amount of resin required to treat the system.

1 . A method for treating fiber comprising the steps of: 
 supplying a first line of secondary fiber which represents a total supply of secondary fiber;    removing a portion of the total supply of secondary fiber in the first line and transporting the portion into a second line wherein a remainder of the total supply of secondary fiber remains in the first line;    treating the second line with a cationic resin treatment;    supplying a third line having virgin fiber;    combining the remainder of secondary fiber in the first line and the virgin fiber in the third line; and    adding the treated secondary fiber in the second line to the combined first line and third line.    
     
     
         2 . The method of  claim 1  wherein a mix time for the cationic resin treatment is in a range from 30 seconds to 90 seconds.  
     
     
         3 . The method of  claim 1  wherein a mix time when the second line is added to the combined first line and third line is in a range from 1 minute to 3 minutes.  
     
     
         4 . The method of  claim 1  wherein the cationic resin treatment includes use of a cationic polyamide-epichlorohydrin resin to treat the secondary fiber in the second line.  
     
     
         5 . The method of  claim 1  wherein the first line and third line are mixed in a blend chest.  
     
     
         6 . The method of  claim 1  wherein the second line is added to the combined first line and third line at a blend chest pump.  
     
     
         7 . A method for treating fiber comprising: 
 supplying a first line of secondary fiber;    supplying a second line of secondary fiber;    treating the second line with a cationic treatment;    supplying a third line having virgin fiber;    combining the secondary fiber in the first line and the virgin fiber in the third line; and    adding the treated secondary fiber in the second line to the combined first line and third line.    
     
     
         8 . The method of  claim 7  wherein the first line and the second line are separate.  
     
     
         9 . The method of  claim 7  wherein the second line is supplied by removing a portion of the secondary fiber from the first line.  
     
     
         10 . The method of  claim 7  wherein the secondary fiber in the second line is provided from a furnish which is separate from a furnish used to supply the first line.  
     
     
         11 . The method of  claim 7  wherein a mix time for the cationic resin treatment is in a range from 30 seconds to 90 seconds.  
     
     
         12 . The method of  claim 7  wherein a mix time when the second line is added to the combined first line and third line is in a range from 1 minute to 3 minutes.  
     
     
         13 . A paper product prepared by a process comprising: 
 supplying a first line of secondary fiber which represents a first portion of a total supply of secondary fiber;    supplying a second line of secondary fiber which represents a second portion of the total supply of secondary fiber;    treating the second line with a cationic resin treatment;    supplying a third line having virgin fiber;    combining the secondary fiber in the first line and the virgin fiber in the third line;    adding the treated secondary fiber in the second line to the combined first line and third line;    sheeting contents of the combined first, second and third lines; and    drying the contents of the combined first, second and third lines.    
     
     
         14 . The paper product of  claim 13  wherein the second line is supplied by removal of secondary fiber from the first line.  
     
     
         15 . The paper product of  claim 13  wherein the cationic resin treatment includes use of a cationic urea-formaldehyde to treat the secondary fiber in the second line.  
     
     
         16 . The paper product of  claim 13  wherein a mix time when the second line is added to the combined first line and third line is in a range from 1 minute to 3 minutes.  
     
     
         17 . The paper product of  claim 13  wherein a mix time for the cationic resin treatment is in a range from 30 seconds to 90 seconds.  
     
     
         18 . The paper product of  claim 13  wherein the cationic resin treatment includes use of a compound selected from the group consisting of: cationic polyamide-epichlorohydrin resins, cationic urea-formaldehyde (UF) and melamine-urea-formaldehyde (MUF) condensation products.  
     
     
         19 . The paper product of  claim 13  wherein the second line is added to the combined first line and third line at a blend chest pump.  
     
     
         20 . The paper product of  claim 13  wherein the secondary fiber in the second line is provided from a furnish which is separate from a furnish used to supply the first line.