Powdery paper-strengthening agent, paper-strengthening agent solution, and paper

Abstract

A powdery paper-strengthening agent comprising a branched (meth)acrylamide-based polymer (A).

1 : A powdery paper-strengthening agent comprising a branched (meth)acrylamide-based polymer (A). 
     
     
         2 : The powdery paper-strengthening agent of  claim 1 , wherein (A) component comprises (meth)acrylamide (a1), anionic vinyl monomer (a2), cationic vinyl monomer (a3), and crosslinkable vinyl monomer (a4). 
     
     
         3 : The powdery paper-strengthening agent of  claim 2 , wherein (a2) component comprises at least either unsaturated sulfonic acids or salts thereof. 
     
     
         4 : The powdery paper-strengthening agent of  claim 2 , wherein (a4) component comprises a vinyl monomer having a N,N-substituted amide group. 
     
     
         5 : The powdery paper-strengthening agent of  claim 2 , wherein
 a content of (a1) component is 59.5 to 98 mol % in (A) component,   a content of (a2) component is 0.5 to 20 mol % in (A) component,   a content of (a3) component is 0.5 to 20 mol % in (A) component, and   a content of (a4) component is 0.001 to 1 mol % in (A) component.   
     
     
         6 : The powdery paper-strengthening agent of  claim 1 , wherein a weight-average molecular weight of (A) component is 1,000,000 to 8,000,000. 
     
     
         7 : A paper-strengthening agent solution comprising the powdery paper-strengthening agent of  claim 1  and water. 
     
     
         8 : Paper to which the paper-strengthening agent solution of  claim 7  is given.