Claims
- 1. An acidified, substantially non-aqueous silica hybrid binder, which contains from about 29% to about 42% total silica expressed as SiO.sub.2, exclusive of any added quantity of curing accelerators, other modifiers, or mixtures thereof, and which comprises:
- (a) a predominant amount of a silica component derived from the hydrolysis of an organic silicate and a lesser amount of a silica component derived from a silica sol; and
- (b) a solvent component which contains:
- (i) from 0 to about 75% by weight of an organic solvent having a volatility equal to or greater than the volatility of a C.sub.1 to C.sub.3 alkyl monohydric alkanol; and
- (ii) from about 25% to 100% by weight of a solvent having a lesser volatility than the volatility of a C.sub.1 to C.sub.3 alkyl monohydric alkanol, said solvent of lesser volatility optionally containing no more than about 90%, by weight, of a solvent selected from the group consisting of n-butyl alcohol, iso-butyl alcohol and sec-butyl alcohol.
- 2. A binder as claimed in claim 1 wherein the silica component derived from the organic silicate ranges from about 52% to about 95% by weight of the total silica present.
- 3. A binder as claimed in claim 2 wherein the organic silicate is tetraethyl orthosilicate.
- 4. A binder as claimed in claim 1 wherein the solvent having the lesser volatility is a glycol ether.
- 5. A binder as claimed in claim 1 wherein the solvent having the lesser volatility is a ketone.
- 6. A binder as claimed in claim 2 wherein the silica component is derived from tetraethyl orthosilicate and the solvent having the lesser volatility is a glycol ether.
- 7. A binder as claimed in claim 2 wherein the silica component is derived from tetraethyl orthosilicate and the solvent having the lesser volatility is a ketone.
- 8. A process for forming the hybrid binder of claim 1 which comprises:
- (a) combining a silica sol and a hydrolyzable organic silicate under acidic conditions;
- (b) hydrolyzing the organic silicate forming silica and by-product alcohol;
- (c) removing an amount of one or more of:
- (1) the alcohol in the product from step (b);
- (2) any C.sub.1 to C.sub.3 alkyl monohydric alcohol solvent added to the system either before, during or after the organic silicate hydrolysis; and
- (3) any other organic solvent that may be present which is of an equal or more volatile nature than the C.sub.1 to C.sub.3 alkyl monohydric alcohols; and
- (d) adding to the resulting intermediate product from step (c) a solvent having a lesser volatility than a C.sub.1 to C.sub.3 alkyl monohydric alcohol, such that the total solvent composition of the final solvent-diluted hybrid binder product comprises at least about 25% by weight of a solvent having a lesser volatility than the volatility of a C.sub.1 to C.sub.3 alkyl monohydric alkanol.
- 9. A process as claimed in claim 8 wherein the organic silicate is an alkyl silicate and the solvent added in step (d) is a glycol ether.
- 10. A process as claimed in claim 8 wherein the organic silicate is an alkyl silicate and the solvent added in step (d) is a ketone.
- 11. A zinc-rich primer which comprises zinc powder and the silica hybrid binder of claim 1.
- 12. A zinc-rich primer which comprises zinc powder and the silica hybrid binder of claim 2.
- 13. A zinc-rich primer which comprises zinc powder and the silica hybrid binder of claim 3.
- 14. A zinc-rich primer which comprises zinc powder and the silica hybrid binder of claim 4.
- 15. A zinc-rich primer which comprises zinc powder and the silica hybrid binder of claim 5.
- 16. A zinc-rich primer which comprises zinc powder and the silica hybrid binder of claim 6.
- 17. A zinc-rich primer which comprises zinc powder and the silica hybrid binder of claim 7.
Parent Case Info
This is a continuation-in-part of U.S. Ser. No. 626,925, filed Dec. 13, 1990 now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
335350 |
Oct 1989 |
EPX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
626925 |
Dec 1990 |
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