Aqueous suspensions of titanium dioxide and cationic amylaceous matter, intended for the production of paper and cardboard

Abstract

Novel aqueous suspensions containing a very specific filler/binder pair, in particular a filler based on titanium dioxide and a binder in the form of a liquid composition of cationic amylaceous material having very specific characteristics in terms of dry matter, viscosity, nitrogen content and pH. A method for producing the suspensions, the use of the suspensions for the production of paper and cardboard and the resulting paper and cardboard are also described.

1 . An aqueous suspension containing:
 a) water,   b) a filler which is titanium dioxide,   c) a liquid composition of cationic amylaceous material having:
 a dry matter by weight of between 10% and 50%, 
 a viscosity, determined according to a T test, of greater than 200 mPa·s and at most equal to 1000 mPa·s, 
 a total nitrogen content at least equal to 0.6% and at most equal to 1.6%, these percentages being expressed by dry weight relative to the dry weight of composition, 
 a pH below 9. 
   
     
     
         2 . The aqueous suspension as claimed in  claim 1 , characterized in that it contains, expressed as % by weight of each of its constituents:
 a) from 20% to 80% of water,   b) from 20% to 80% of a filler which is titanium dioxide,   c) from 0.1% to 5%, preferentially from 0.5% to 2%, of a liquid composition of cationic amylaceous material having:
 a dry matter by weight of between 10% and 50%, 
 a viscosity, determined according to a T test, of greater than 200 mPa·s and at most equal to 1000 mPa·s, 
 a total nitrogen content at least equal to 0.6% and at most equal to 1.6%, these percentages being expressed by dry weight relative to the dry weight of composition, 
 a pH below 9. 
   
     
     
         3 . The aqueous suspension as claimed in  claim 1 , characterized in that the liquid composition of cationic amylaceous materials has a dry matter by weight of preferentially between 10% and 30%. 
     
     
         4 . The aqueous suspension as claimed in  claim 1 , characterized in that the liquid composition of cationic amylaceous materials has a pH of between 3.5 and 8.5. 
     
     
         5 . The aqueous suspension as claimed in  claim 1 , characterized in that the origin of the amylaceous materials is potato flour, corn, wheat, pea, or mixtures thereof. 
     
     
         6 . The aqueous suspension as claimed in  claim 1 , characterized in that the titanium dioxide is of rutile or anatase origin, and preferentially rutile origin. 
     
     
         7 . The aqueous suspension as claimed in  claim 1 , characterized in that it can also contain talc, calcium carbonate in natural or synthetic form, and mixtures of these fillers. 
     
     
         8 . A method for producing an aqueous suspension of a filler and a cationic amylaceous material by mixing between:
 a) water,   b) a filler which is titanium dioxide,   c) a liquid composition of cationic amylaceous material having:
 a dry matter by weight of between 10% and 50%, 
 a viscosity, determined according to a T test, of greater than 200 mPa·s and at most equal to 1000 mPa·s, 
 a total nitrogen content at least equal to 0.6% and at most equal to 1.6%, these percentages being expressed by dry weight relative to the dry weight of composition, 
 a pH below 9. 
   
     
     
         9 . A method for producing a paper or a cardboard, by using an aqueous suspension as claimed in  claim 1 , either in the coating step or in the wet end of production of the sheet. 
     
     
         10 . A paper or a cardboard obtained by using an aqueous suspension as claimed in  claim 1 , either in the coating step or in the wet end of production of the sheet. 
     
     
         11 . The aqueous suspension as claimed in  claim 2 , characterized in that the liquid composition of cationic amylaceous materials has a dry matter by weight of preferentially between 10% and 30%. 
     
     
         12 . The aqueous suspension as claimed in  claim 2 , characterized in that the liquid composition of cationic amylaceous materials has a pH of between 3.5 and 8.5.