Silica-based structurants and processes for making thereof

Abstract

The disclosure relates to a silica-based structurant and methods of making such a structurant. According to one embodiment, the structurant may include 55 wt % to 90 wt % of a silica having a [Na 2 O]/[SiO 2 ] molar ratio of from 0.02 to 0.14 and at least 15 wt % of an adjunct salt. The structurant may have a hydrated particle size distribution such that no more than 30 wt % of the structurant has a hydrated particle size greater than 45 micrometers according to the Structurant Residue Test. The structurant may also have a tapped bulk density of from 200 g/L to 300 g/L. Methods of making the structurant include combining starting materials with a non-stoichiometric amount of acid, then drying the reaction mixture without first washing any silica-based particles to produce a silica-based structurant with adjunct salt.

1 . A process of forming a structurant comprising:
 combining water, SiO 2 , NaO 2  and a non-stoichiometric amount of acid to form a silica mixture having a [Na 2 O]/[SiO 2 ] molar ratio of from 0.02 to 0.14;   drying the silica mixture to form a structurant having 55 wt % to 90 wt % of silica with a [Na 2 O]/[SiO 2 ] molar ratio of from 0.02 to 0.14 and at least 15 wt % of an adjunct salt, wherein the structurant has a hydrated particle size distribution such that no more than 30 wt % of the structurant has a hydrated particle size greater than 45 micrometers according to the Structurant Residue Test and a tapped bulk density of from 200 g/L to 300 g/L.   
     
     
         2 . The process of  claim 1 , further comprising combining an adjunct salt source to form the silica mixture. 
     
     
         3 . The process of  claim 1 , wherein the acid comprises H 2 SO 4 . 
     
     
         4 . A process of forming a structurant comprising:
 performing the following chemical reaction in a reaction mixture:
   (ω.R).(H 2 O)+R(SiO 2 ).Na 2 O+A(H 2 SO 4 )→R(SiO 2 ).(1−A)Na 2 O+A(Na 2 SO 4 )+(ω.R+A)(H 2 O)
 
   wherein A is the amount of acid used in the reaction, relative to a stoichiometric ratio for complete neutralization, R is the silicate ratio, [Na 2 O]/[SiO 2 ] and co is the molar amount of water added to the reaction mixture relative to moles of SiO 2 ; and   drying the reaction mixture to obtain a structurant.   
     
     
         5 . The process of  claim 4 , wherein A is from 0.6 to 1.0 
     
     
         6 . The process of  claim 5 , wherein, A is from 0.7 to 0.9. 
     
     
         7 . The process of  claim 4 , wherein R is from 1.6 to 3.4. 
     
     
         8 . The process of  claim 7 , wherein R is from 2.4 to 3.3 
     
     
         9 . The process of  claim 8 , wherein R is from 2.8 to 3.2 
     
     
         10 . The process of  claim 4 , wherein ω is from 20 to 100. 
     
     
         11 . The process of  claim 10 , wherein ω is from 25 to 75. 
     
     
         12 . The process of  claim 11 , wherein ω is from 30 to 60. 
     
     
         13 . The process of  claim 12 , wherein ω is from 32 to 50.