Coating compositions with anticorrosion properties

Abstract

Anticorrosive coating compositions as disclosed comprise a binding polymer and an aluminum phosphate corrosion inhibiting pigment dispersed therein. The coating composition comprises up to 25 percent by weight aluminum phosphate. The binding polymer can include solvent-borne polymers, water-borne polymers, solventless polymers, and combinations thereof. The aluminum phosphate is made by sol gel process of combining an aluminum salt with phosphoric acid and a base material. Aluminum phosphate colloidal particles are nanometer sized, and aggregate to form substantially spherical particles. The coating composition provides a controlled delivery of phosphate anions of 100 to 1,500 ppm, depending on post-formation treatment of the aluminum phosphate, and has a total solubles content of less than 1500 ppm, The amorphous aluminum phosphate is free of alkali metals and alkaline earth metals, and has a water adsorption potential of up to about 25 percent by weight water when present in a cured film.

1 - 32 . (canceled) 
     
     
         33 . A method of making aluminum phosphate comprising:
 combining an aluminum source with phosphorous source to form a mixture;   adding a base material with the mixture to form a dispersion of colloidal aluminum phosphate particles in liquid;   forming a gel from the colloidal aluminum phosphate particles; and   heating the gel to remove the liquid and provide solid aluminum phosphate particles.   
     
     
         34 . The method as recited in  claim 33  wherein the solid aluminum phosphate particles comprise amorphous aluminum phosphate. 
     
     
         35 . The method as recited in  claim 33  wherein, during the step of combining, the aluminum source is aluminum nitrate. 
     
     
         36 . The as recited in  claim 33  wherein, during the step of adding, the base material is ammonium hydroxide. 
     
     
         37 . The method as recited in  claim 33  wherein, during the step of adding, ammonium phosphate is formed. 
     
     
         38 . The method as recited in  claim 33  wherein the aluminum phosphate is free of alkali metal cations. 
     
     
         39 . The method as recited in  claim 33  wherein the gel comprises a three-dimensional structure of the colloidal aluminum phosphate particles. 
     
     
         40 . The method as recited in  claim 33  wherein, the step of forming a gel comprises adding a further amount of the base material to the colloidal aluminum phosphate particles. 
     
     
         41 . The method as recited in  claim 33  wherein the solid aluminum phosphate particles are substantially spherical in shape. 
     
     
         42 . The method as recited in  claim 33  wherein the solid aluminum phosphate particles have a substantially uniform size distribution. 
     
     
         43 . A method of making aluminum phosphate comprising:
 combining an aluminum salt with phosphoric acid to form a mixture;   forming a sol by combining the mixture with a base material, the sol comprising a dispersion of colloidal aluminum phosphate particles in liquid;   forming a gel from the sol, the gel comprising aggregated aluminum sulfate particles in the liquid.   
     
     
         44 . The method as recited in  claim 43  wherein the gel has a three-dimensional structure of the aggregated colloidal aluminum phosphate particles. 
     
     
         45 . The method as recited in  claim 43  wherein the aluminum salt is aluminum nitride, and wherein the base material is ammonium hydroxide. 
     
     
         46 . The method as recited in  claim 43  wherein, during the step of forming a sol, ammonium phosphate is produced. 
     
     
         47 . The method as recited in  claim 43  further comprising forming solid aluminum phosphate particles by heating the gel. 
     
     
         48 . The method as recited in  claim 47  wherein the solid aluminum phosphate comprises amorphous aluminum phosphate. 
     
     
         49 . The method as recited in  claim 43  wherein the aluminum phosphate particles are substantially spherical in shape and have a substantially uniform particle size distribution. 
     
     
         50 . A method of making amorphous aluminum phosphate comprising:
 combining aluminum nitrate with phosphoric acid to form a mixture;   adding a base material to the mixture to form a sol comprising a dispersion of colloidal aluminum phosphate particles in liquid;   treating the sol to cause the colloidal particles to aggregate and form a gel of linked-together aluminum phosphate particles; and   treating the gel to produce solid aluminum phosphate particles comprising amorphous aluminum phosphate.   
     
     
         51 . The method as recited in  claim 50  wherein during the process of adding, ammonium phosphate is produced. 
     
     
         52 . The method as recited in  claim 50  wherein the aluminum phosphate is alkali metal free.