Wet-strength finishing agents for paper

Abstract

They are mixtures of (a) from 1 to 99.9% by weight of a water-soluble epihalohydrin-crosslinked polyamidoamine and (b) from 0.1 to 20% by weight of at least one other cationic polymer.

We claim:  
     
         1 . Wet strength enhancers for paper, comprising mixtures of 
 (a) from 1 to 99.9% by weight of an epihalohydrin-crosslinked polyamidoamine and    (b) from 0.1 to 20% by weight of at least one other cationic polymer from the group consisting of 
 addition polymers containing vinylamine units,  
 dicyandiamide-formaldehyde condensates.  
   
     
     
         2 . Wet strength enhancers as claimed in  claim 1 , comprising 
 (a) an epihalohydrin-crosslinked polyamidoamine and    (b) a 1-100 mol % hydrolyzed polyvinylformamide.    
     
     
         3 . A process for producing paper by draining a paper stock in the presence of a wet strength enhancer, which comprises using wet strength enhancers comprising mixtures of 
 (a) from 1 to 99.9% by weight of an epihalohydrin-crosslinked polyamidoamine and    (b) from 0.1 to 20% by weight of at least one other cationic polymer from the group consisting of 
 addition polymers containing vinylamine units and  
 dicyandiamide-formaldehyde condensates.  
   
     
     
         4 . A process as claimed in  claim 3 , wherein the paper stock is admitted with (a) an epihalohydrin-crosslinked polyamidoamine and (b) at least one other cationic polymer concurrently or in any order, said components (a) and (b) being used in any event in a weight ratio of from 1 to 99.9:0.1 to 20.  
     
     
         5 . The use of the wet strength enhancers of either of claims  1  and  2  in the production of paper by addition to the paper stock before sheet formation in amounts from 0.1 to 4% by weight, based on dry fiber.