PROCESS FOR PRODUCING PROTECTIVE GLASS COATINGS

• US 3,811,918 A
• Filed: 12/20/1971
• Issued: 05/21/1974
• Est. Priority Date: 12/20/1971
• Status: Expired due to Term

• Current Assignee: Owens-Illinois Glass Container, Inc. (O-I Glass, Inc.)
• Original Assignee: Leon Levene
• Inventors: Levene, Leon
• Primary Examiner(s): Martin, William D.
• Assistant Examiner(s): Schmidt, William H.
• Application Number:
  US05/210,104
• Time in Patent Office: 883 Days
• Field of Search: 260/448AD,46.5R,46.5E 117/121,169,125,47H,14R,129 65/DIG.14
• US Class Current: 427/375
• CPC Class Codes: C03C 17/02 with glass C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C04B 35/10 based on aluminium oxide
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4505 characterised by the method of application
• CPC Class Codes: C04B 41/5022 with vitreous materials composition of vitreous glazes and enamels C03C; ceramic pigments C09C1/0009
• CPC Class Codes: C04B 41/86 Glazes; Cold glazes
• CPC Class Codes: C07F 7/04 Esters of silicic acids
• CPC Class Codes: Y10S 65/901 Liquid phase reaction process

Abstract

A process for providing a silicate glass coated and protected inorganic substrate which comprises applying a substantially gel resistant, mineral acid stabilized, clear solution having a pH of less than about 1.5 of a substrate compatible glass composition in the form of a glass precursor onto the substrate and then heating the precursor to a temperature and for a time sufficient to convert the precursor into a silicate glass coating on the substrate. The precursor is prepared by hydrolyzing prescribed silicon alkoxides with less than a stoichiometric amount of water so as to prepare a clear solution of a partially hydrolyzed silicon alkoxide, which partially hydrolyzed silicon alkoxide solution is then reacted with an aqueous solution of a metal oxide forming compound so as to form a solution of the precursor or with a metal alkoxide so as to form a clear solution of a further hydrolyzable metallosiloxane, which latter clear solution of the further hydrolyzable metallosiloxane is then reacted with either a quantity of water sufficient to hydrolyze residual alkoxy groups or with an aqueous solution of a metal compound which is convertible to a metal oxide so as to form a solution of the glass precursor.

Claims

2. reacting the partially hydrolyzed silicon alkoxide with a metal alkoxide so as to form a clear solution of a soluble, further hydrolyzable metallosiloxane;

3. The process of claim 2 wherein n in said silicon alkoxide is O and wherein the hydrolysis is effected with about 0.3 to about 1.5 equivalents of water per equivalent of silicon alkoxide, and wherein said hydrolysis is done in the presence of an organic solvent.

4. The process of claim 3 wherein the silicon alkoxide is tetraethylsilicate.

5. The process of claim 3 wherein said substrate is an alumina substrate.

6. The process of claim 5 wherein said applying is done by spraying said substrate while at an elevated temperature, said temperature and the spraying rate being so selected so as to essentially prevent wetting of the surface of said substrate.

7. The process of claim 3 wherein said applied solution contains said glass precursor in a concentration of about 5 to about 20 percent by weight based on the total weight of said precursor'"'"''"'"'s theoretical oxide glass composition.

8. The process of claim 7 wherein said glass composition consists essentially of, on a theoretical oxide basis, about 37 percent SiO2, about 10 percent Al2O3, about 35 percent BaO, and about 18 percent B2O3 by weight.

9. The process of claim 1 and further including adjusting the pH of the clear solution of said glass precursor, as formed after said reaction with said aqueous solution of a metal compound, with a mineral acid to a pH of less than about 1.5.

10. The process of claim 9 wherein said mineral acid is nitric acid.

11. A process for providing a silicate glass coated and protected inorganic substrate which comprises:

I. applying a substantially gel resistant, mineral acid stabilized clear solution, having a pH of less than about 1.5, of a substrate-compatible glass composition in the form of a glass precursor onto said substrate, said soLution being prepared by;

12. The process of claim 11 wherein said applied solution has a pH of between about 1.5 and about 1.

13. The process of claim 11 wherein the pH of the solution of said glass precursor after reaction with said additional quantity of water is between about 2.5 and about 5 and further including the step of adjusting said pH to less than about 1.5.

14. A process for providing a silicate glass coated and protected inorganic substrate which comprises:

I. applying a substantially gel resistant, mineral acid stabilized clear solution, having a pH of less than about 1.5, of a substrate-compatible glass composition in the form of a glass precursor onto said substrate, said solution being prepared by;

15. The process of claim 14 wherein said metal compound is a metal salt of an organic acid.

16. A process for providing a silicate glass coated and protected inorganic substrate which comprises:

I. applying a clear solution having a pH of less than about 1.5 of a hydrolyzed glass precursor onto said substrate, said precursor being prepared by;

17. The process of claim 16 wherein at least part of said additional quantity of water is a water solution of a metal compound which decomposes to an oxide below about 600*C.

18. The process of claim 17 wherein said metal alkoxide is a compound of the formula M(OR'"'"''"'"')X wherein M represents a metal, R'"'"''"'"' represents an alkyl of 1 to 6 carbon atoms, and X is an integer equal to the valence of M.

19. The process of claim 17 wherein said metal alkoxide is a double metal alkoxide of the formula M1M2(OR)X wherein M1 and M2 are metals, R is an alkyl of 1 to 7 carbon atoms and X corresponds to the combined valences of M1 and M2.

20. The process of claim 16 wherein n is O, the amount of water which is combined with said silicon alkoxide is about one equivalent per equivalent of silicon alkoxide, said combining being done in the presence of a C1 to C6 alcohol, and wherein said acid hydrolysis catalyst is present in an amount sufficient to provide a pH of between about 2.5 to about 5 and further including the step of adjusting the pH of the clear solution formed by said reacting of said clear solution of said further hydrolyzable metallosiloxane with an additional quantity of water to less than about 1.5.

21. A process for increasing the smoothness of the surface of an alumina substrate which comprises:

I. spraying a clear solution in a solvent of an alumina-compatible, hydrolyzed silicate-glass precursor onto said alumina substrate while at an elevated temperature, said precursor being prepared by

22. The process of claim 21 wherein said precursor is heated to form said silicate glass coating within a period of time of about 15 to about 90 seconds.

23. The process of claim 22 wherein said silicon alkoxide and water is reacted in the presence of ethanol and wherein said elevated temperature is between about 150*C. to about 300*C.

24. A process for providing a silicate glass-coated and protected inorganic substrate which comprises:

I. spraying a clear solution in a solvent of a hydrolyzed silicate glass precursor onto said substrate while said substrate is at an elevated temperature, said temperature and the spraying rate being so selected so as to essentially prevent wetting of the surface of said substrate and so that the solvent substantially evaporates upon contact with said substrate, leaving a deposit thereon of said silicate glass precursor, said precursor being prepared by