Process for the production of paper

Abstract

The invention relates to a process for the production of paper which comprises (i) providing a main aqueous flow containing cellulosic fibers; (i) introducing one or more retention components into the main aqueous flow to form a main aqueous flow containing one or more retention components; (iii) providing a diluting aqueous flow; (iv) introducing a low molecular weight cationic organic polymer into the diluting aqueous flow to form a diluting aqueous flow containing a low molecular weight cationic organic polymer, the low molecular weight cationic organic polymer having a weight average molecular weight up to 5,000,000; (v) introducing the diluting aqueous flow containing a low molecular weight cationic organic polymer into the main aqueous flow containing one or more retention components to form a resulting aqueous flow; and then (vi) ejecting the resulting aqueous flow onto a wire and dewatering the resulting aqueous flow to form a web of paper.

1 . A process for the production of paper which comprises 
 (i) providing a main aqueous flow containing cellulosic fibers;    (i) introducing one or more retention components into the main aqueous flow to form a main aqueous flow containing one or more retention components;    (iii) providing a diluting aqueous flow;    (iv) introducing a low molecular weight cationic organic polymer into the diluting aqueous flow to form a diluting aqueous flow containing a low molecular weight cationic organic polymer, the low molecular weight cationic organic polymer having a weight average molecular weight up to 5,000,000;    (v) introducing the diluting aqueous flow containing a low molecular weight cationic organic polymer into the main aqueous flow containing one or more retention components to form a resulting aqueous flow; and then    (vi) ejecting the resulting aqueous flow onto a wire and dewatering the resulting aqueous flow to form a web of paper.    
     
     
         2 . The process of  claim 1 , wherein the main aqueous flow has a higher consistency than the diluting aqueous flow.  
     
     
         3 . The process of  claim 1 , wherein the diluting aqueous flow is white water obtained by dewatering the resulting aqueous flow.  
     
     
         4 . The process of  claim 1 , wherein the retention components are selected from the group consisting of microparticle retention systems and retention systems comprising at least two organic polymers.  
     
     
         5 . The process of  claim 4 , wherein the retention components comprise at least one cationic organic polymer and anionic silica-based particles.  
     
     
         6 . The process of  claim 5 , wherein the cationic organic polymer is cationic starch or cationic acrylamide-based polymer.  
     
     
         7 . The process of  claim 1 , wherein the low molecular weight cationic organic polymer has a weight average molecular weight within the range from 500,000 to 3,000,000:  
     
     
         8 . The process of  claim 1 , wherein the low molecular weight cationic organic polymer is a chain-growth polymer.  
     
     
         9 . The process of  claim 1 , wherein the low molecular weight cationic organic polymer is a homopolymer or copolymer based on diallyldimethylammonium chloride.  
     
     
         10 . A process for the production of paper on a paper machine containing a dilution headbox which comprises 
 (i) introducing one or more retention components into a main aqueous flow containing cellulosic fibers, and feeding the obtained main aqueous flow into the dilution headbox;    (ii) introducing low molecular weight cationic organic polymer having a weight average molecular weight up to 5,000,000 into a diluting aqueous flow and feeding the obtained diluting aqueous flow into the dilution headbox;    (iii) mixing the obtained main aqueous flow with the obtained diluting aqueous flow in the headbox to form a resulting aqueous flow; and    (iv) ejecting the resulting aqueous flow onto a wire and dewatering the resulting aqueous flow to form a web of paper.    
     
     
         11 . The process of  claim 10 , wherein the retention components comprise two or more components which, when used in combination, give better retention than is obtained when not adding the components.  
     
     
         12 . The process of  claim 10 , wherein the retention components are selected from the group consisting of organic polymers, organic polymers in combination with aluminium compounds, and organic polymers in combination with inorganic microparticles.  
     
     
         13 . The process of  claim 10 , wherein the low molecular weight cationic organic polymer has a weight average molecular weight within the range from 500,000 to 3,000,000.  
     
     
         14 . The process of  claim 10 , wherein the diluting aqueous flow is white water obtained by dewatering the resulting aqueous flow.  
     
     
         15 . The process of  claim 10 , wherein the paper machine produces paper at a speed of from 300 to 2500 m/min.  
     
     
         16 . The process of  claim 10 , wherein it comprises recycling of white water and introduction of from 0 to 30 tons of fresh water per ton of dry paper produced.  
     
     
         17 . The process of  claim 10 , wherein the retention components comprises at least one organic polymer containing one or more aromatic groups.  
     
     
         18 . The process of  claim 10 , wherein the low molecular weight cationic organic polymer is a homopolymer or copolymer based on diallyldimethylammonium chloride.