Nonreflective glass coatings

Claim 1

A PROCESS FOR THE MANUFACTURE OF SURFACES COATED WITH FINELY DIVIDED SILICA WHICH COMPRISES MIXING AN AQUEOUS SOLUTION OF SODIUM SILICATE HAVING A WEIGHT RATIO OF NA2O TO SIO2 WITHIN THE RANGE OF FROM ABOUT 1:24 TO 1:4 AND A CONCENTRATION OF SIO2 RANGING FROM ABOUT 1 TO 30% BY WEIGHT WITH AMMONIA IN AN AMOUNT RANGING FROM ABOUT 80 TO 500% OF THE QUANTITY REQUIRED WHEN SLOWLY ADDED TO THE SILICATE SOLUTION, TO PRODUCE THE FIRST APPEARANCE OF COACERVATION IN THE MIXTURE; THE HIGHER CONCENTRATIONS OF SILICA BEING EMPLOYED WITH THE LOWER RATIOS OF NA2O TO SIO2; CONTACTING AS AN INSOLUBILIZING AGENT A SURFACE HAVING AN ACIDIC PH; THE QUANTITY OF NH3 ADDED VARYING FROM ABOUT 0.8 TO 4 PARTS BY WEIGHT TO 1 PART OF SIO2 IN THE SILICATE SOLUTION; CONDUCTING THE PRECIPITATION ON THE SURFACE IN SUCH MANNER THAT THE REQUIRED FILM THICKNESS IS DEVELOPED AND SO THE AMMONIA IS COMPLETELY MIXED IN NOT LATER THAN THE REACTION WITH THE ACIDIFIED SURFACE, THE CONCENTRATION OF THE SOLUTION BEING SO CHOSEN THAT THE TOTAL SIO2 CONTENT IN THE FINAL MIXTURE IS WITHIN THE RANGE OF FROM 0.5 TO 8% BY WEIGHT AND RECOVERING THE RESULTING SURFACE COATED WITH FINELY DIVIDED SILICA FREE FROM SILICA GEL.