Method for the production of tissue paper

Abstract

A method for the production of a tissue paper web, which is produced from a pulp suspension comprised of fibers, the pulp suspension having a refining degree of less than 21°SR and being of such condition that it is possible to produce from said pulp suspension a laboratory sheet according to TAPPI 205 SP 95 (Rapid Köthen) whose breaking length measured according to TAPPI 220 and TAPPI 494 at least a specific refining degree (RD specific ) is greater than or equal to the value resulting from 0.55 (km/SR)*(RD specific −10°SR), whereby the specific refining degree is selected from a refining range from 15°SR to less than 21°SR, in particular 15°SR to 19°SR.

1 . A method for the production of a pulp suspension comprised of fibers, with which at least one suspension fraction is produced with the following steps:
 providing a high-consistency feed pulp suspension comprised of fibers and having a consistency of more than 20% and a refining degree of less than 15°SR; and   refining the high-consistency feed pulp suspension to a refining degree of 15°SR or more to obtain the suspension fraction.   
   
   
       2 . The method according to  claim 1 , wherein the suspension fraction for producing the pulp suspension is mixed with another suspension fraction, whereby the other suspension fraction is refined from a low-consistency feed pulp suspension with a consistency of less than 10%. 
   
   
       3 . The method according to  claim 2 , wherein the suspension fraction for producing the pulp suspension is mixed with another suspension fraction, whereby the other suspension fraction is refined from a low-consistency feed pulp suspension with a consistency of less than 5%. 
   
   
       4 . The method according to  claim 2 , wherein the suspension fraction produced from a low-consistency feed pulp suspension has a higher refining degree than the suspension fraction produced from a high-consistency feed pulp suspension. 
   
   
       5 . The method according to  claim 4 , wherein the high-consistency feed pulp suspension has a refining degree of 12°SR to 13°SR and the suspension fraction produced therefrom has a refining degree of 15°SR to 19°SR. 
   
   
       6 . The method according to  claim 5 , wherein the high-consistency feed pulp suspension has a refining degree of 12°SR to 13°SR and the suspension fraction produced therefrom has a refining degree of 15°SR to 17°SR. 
   
   
       7 . The method according to  claim 1 , wherein the refining operation is performed several times in succession. 
   
   
       8 . The method according to  claim 1 , wherein the high-consistency feed pulp suspension is refined with a refining energy in the range from 150 kWh to 300 kWh. 
   
   
       9 . The method according to  claim 8 , wherein the high-consistency feed pulp suspension has a consistency in the range from more than 20% to 40%. 
   
   
       10 . The method according to  claim 2 , wherein enzymes are added to the low-consistency feed pulp suspension for refinement. 
   
   
       11 . The method according to  claim 1 , wherein the high-consistency feed suspension has a low strength produced from a low-consistency feed suspension of low strength. 
   
   
       12 . The method according to  claim 11 , wherein the concentration is performed by means of a worm extruder. 
   
   
       13 . The method according to  claim 2 , wherein at least one of enzymes and agents for at least one of increasing the dry strength (dry strength agents) and increasing the wet strength (wet strength agents) are added to the low-consistency feed pulp suspension. 
   
   
       14 . The method according to  claim 13 , wherein the dry strength agent is comprised of carbon methyl cellulose. 
   
   
       15 . The method according to  claim 10 , wherein the enzymes are added to the low-consistency feed suspension at a temperature in the range from 25° C. to 70° C. 
   
   
       16 . The method according to  claim 15 , wherein the enzymes are added to the low-consistency feed suspension with a pH-value in the range from 5 to 8. 
   
   
       17 . The method according to  claim 16 , wherein the enzymes are allowed to work for a period of 1 to 2 hours on the low-consistency feed suspension. 
   
   
       18 . The method according to  claim 17 , wherein the enzymes are added in the pulper. 
   
   
       19 . The method according to  claim 1 , wherein the high-consistency feed pulp suspension is refined at a temperature up to 80° C. 
   
   
       20 . A method for the production of a fibrous web, with a pulp suspension produced by the method according to  claim 6 .