Method for bonding at least two tissue papers to each other

Abstract

A method for autogenously bonding at least two plies of tissue paper with a basis weight from 10 to 45 g/m 2 comprises the steps of: laying the plies face-to-face; ultrasonically bonding the plies to each other with the help of at least one ultrasonic horn which oscillates perpendicular to the surface to the tissue paper plies. A multi-ply tissue paper produced by the method is also described.

1 . A method for autogenously bonding at least two plies of tissue paper with a basis weight from 10 to 45 g/m 2  comprises the steps of laying the plies face-to-face, 
 bonding the plies to each other with the help of ultrasonic means having at least one ultrasonic horn which oscillates perpendicular to the surface of the tissue paper plies    
     
     
         2 . The method according to  claim 1 , wherein dry tissue paper plies are bonded.  
     
     
         3 . The method according to  claim 1 , wherein the tissue paper comprises purely cellulosic fibres.  
     
     
         4 . The method according to  claim 1 , wherein at least one of the plies is chosen from the group of dry-creped tissue paper, through-air-dried tissue paper and impulse embossed dried tissue paper  
     
     
         5 . The method according to  claim 1 , wherein the at least one horn oscillates with a frequency from 15 to 50 kHz.  
     
     
         6 . The method according to  claim 1 , wherein the bonding step results in a ply-bonding zone, and a bonding area defined as the sum of all areas of the bonds in said ply-bonding zone, said bonding area ranging from 0.5 to 50% of the area of the ply-bonding zone.  
     
     
         7 . The method according to  claim 6 , wherein the bonding area ranges from 2 to 40% of the area of the ply-bonding zone.  
     
     
         8 . The method according to  claim 6 , wherein the bonding area ranges from 5 to 20% of the area of the ply-bonding zone.  
     
     
         9 . The method according to  claim 1 , wherein the pressure force between the at least one horn and the tissue paper plies to be bonded is from 50 to 700 N.  
     
     
         10 . The method according to  claim 1 , wherein the pressure force between the at least one horn and the tissue paper plies to be bonded is from 200 to 500 N.  
     
     
         11 . The method according to  claim 1 , wherein the paper plies are ultrasonically bonded while they are transported at speed from 50 to 1800 m/s.  
     
     
         12 . The method according to  claim 1 , wherein the paper plies are ultrasonically bonded while they are transported at speed from 300 to 800 m/s.  
     
     
         13 . The method according to  claim 1 , wherein lotion is added to the bonded surface.  
     
     
         14 . The multi-ply tissue paper, each ply of the tissue paper having a basis weight from 10 to 45 g/m 2 , wherein said multi-ply tissue paper is bonded autogenously by ultrasonic means.  
     
     
         15 . The multi-ply tissue paper according to  claim 14 , wherein the sum of the areas of the bonds is from 0.5 to 50% of the area of the ply-bonding zone.  
     
     
         16 . The multi-ply tissue paper according to  claim 14 , wherein the sum of the areas of the bonds is from 2-40% of the area of the ply-bonding zone.  
     
     
         17 . The multi-ply tissue paper according to  claim 14 , wherein the sum of the areas of the bonds is from 5-20% of the area of the ply-bonding zone.  
     
     
         18 . The multi-ply tissue paper according to  claim 14 , wherein the tissue paper comprises purely cellulosic fibres.  
     
     
         19 . The multi-ply tissue paper according to  claim 14 , wherein at least one of the plies is chosen from the group of dry-creped tissue paper, through-air-dried tissue paper and impulse embossed dried tissue paper.  
     
     
         20 . The multi-ply tissue paper according to  claim 14 , wherein the tissue paper contains a lotion.