Processes for clay exfoliation and uses thereof

Abstract

The present invention provides methods for producing exfoliated clay platelets from a swellable clay material. In embodiments, the method for producing exfoliated clay platelets includes providing an exfoliating agent comprising an anionic extractant, and exposing the swellable clay material to the exfoliating agent, wherein the exfoliating agent produces exfoliated clay platelets from the swellable clay material. Methods for treating paper precursors and paper sheets are also disclosed, as are paper products formed from such paper precursors or paper sheets.

1 . A method for producing exfoliated clay platelets from a swellable clay material, comprising:
 providing an exfoliating agent comprising an anionic extractant, and   exposing the swellable clay material to the exfoliating agent, wherein the exfoliating agent produces exfoliated clay platelets from the swellable clay material.   
     
     
         2 . The method of  claim 1 , wherein the anionic extractant comprises sodium phosphate monobasic dihydrate. 
     
     
         3 . The method of  claim 1 , wherein the exfoliating agent is formulated to have a basic pH. 
     
     
         4 . The method of  claim 3 , wherein the exfoliating agent comprises sodium hydroxide. 
     
     
         5 . The method of  claim 1 , further comprising a step of applying ultrasonication simultaneous with or following the step of exposing the swellable clay material to the exfoliating agent. 
     
     
         6 . An exfoliating formulation comprising an anionic extractant in a basic solution, wherein the exfoliating formulation interacts with a swellable clay to produce exfoliated clay platelets. 
     
     
         7 . The formulation of  claim 6 , wherein the anionic extractant comprises a phosphate. 
     
     
         8 . A method of treating a paper precursor comprising:
 exfoliating a swellable clay material with the formulation of  claim 6  to produce a plurality of exfoliated clay platelets, and   admixing the plurality of exfoliated clay platelets with the paper precursor.   
     
     
         9 . A paper product formed from the paper precursor treated according to the method of  claim 8 . 
     
     
         10 . The method of  claim 8 , wherein the step of admixing takes place in a wet end of a papermaking process. 
     
     
         11 . The method of  claim 8 , further comprising treating at least some of the plurality of exfoliated clay platelets with a cationic starch before admixing them with the paper precursor. 
     
     
         12 . The method of  claim 8 , further comprising treating at least some of the plurality of exfoliated clay platelets with an amine-containing polycation before admixing them with the paper precursor. 
     
     
         13 . The method of  claim 8 , wherein at least some of the plurality of exfoliated clay platelets are associated with a latex formulation to form a latex-clay composite. 
     
     
         14 . The method of  claim 8 , further comprising treating at least some of the exfoliated clay platelets with an oil resistant coating formulation before admixing them with the paper precursor. 
     
     
         15 . A method of treating a paper sheet comprising:
 exfoliating a swellable clay material with the formulation of  claim 6  to produce a plurality of exfoliated clay platelets, and   applying the plurality of exfoliated clay platelets with the paper sheet.   
     
     
         16 . The method of  claim 15 , wherein the step of applying takes place in a size press of a papermaking process. 
     
     
         17 . A paper product, formed from a paper sheet treated in accordance with the method of  claim 15 .