US4647479A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Primer over hand-cleaned rusted steel
Assignee: PPG Industries Ohio Inc
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Filing: 1986-03-17
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Granted: 1987-03-03
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Expires: 2006-03-17
Abstract
Abstract A corrosion-inhibiting coating composition for application onto rusted steel or iron surfaces is disclosed. The coating composition comprises an organic silicate, citric acid, and a non-aqueous solvent. The organic silicate is preferably present in an amount sufficient to provide about 12% to 24% silicon dioxide in the cured coating from the composition and is preferably pre-hydrolyzed in an amount of about 70% to 90%. Citric acid is preferably present in an amount of about 0.1 to 0.2 grams per cubic centimeter of the coating composition. Dissolution and complexation of the rust by the citric acid provides a pigment which causes the organic silicate to become a film-forming binder. Zinc chloride is preferably added to the composition to increase the rate of rust dissolution and to improve binder properties.
Inventors
- 👤 Ernesto Montes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:12
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/02; B; B05; B05D; B05D3/00; B05D3/10; B05D3/102; B05D7/00; B05D7/14; B05D7/16; C09; C09D; C09D5/00; C09D5/08
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
101 words
A process for dissolving rust on a rusted metal substrate and for protecting the substrate against further corrosion comprising: applying a rusted metal substrate a non-film forming coating composition having a pH of from about 3.0 to about 4.5 comprising: an organic silicate in an amount sufficient to provide at least 12% by weight silicon dioxide in a cured coating from the coating composition; citric acid in a concentration sufficient to dissolve substantially all of the rust on the substrate; a non-aqueous solvent; allowing the coating composition to at least partially cure; and applying a top coat over the coating composition.
Claim 2
Dependent Claim
101 words
A process for dissolving rust on a rusted metal substrate and for protecting the substrate against further corrosion comprising: applying a rusted metal substrate a non-film forming coating composition having a pH of from about 3.0 to about 4.5 comprising: an organic silicate in an amount sufficient to provide at least 12% by weight silicon dioxide in a cured coating from the coating composition; citric acid in a concentration sufficient to dissolve substantially all of the rust on the substrate; a non-aqueous solvent; allowing the coating composition to at least partially cure; and applying a top coat over the coating composition.
Claim 3
Dependent Claim
18 words
A process as claimed in claim 1 wherein the organic silicate in the coating composition is ethyl silicate.
Claim 4
Dependent Claim
41 words
A process as claimed in claim 1 wherein the organic silicate is present in the coating composition in an amount sufficient to provide from about 12% to about 24% by weight silicon dioxide in a cured coating from the coating composition.
Claim 5
Dependent Claim
40 words
A process as claimed in claim 3 wherein the organic silicate is present in the coating composition in an amount which provides from about 14% to about 18% by weight silicon dioxide in a cured coating from the coating composition.
Claim 6
Dependent Claim
27 words
A process as claimed in claim 1 wherein the organic silicate in the coating composition is pre-hydrolyzed in an amount of from about 70% to about 90%.
Claim 7
Dependent Claim
27 words
A process as claimed in claim 5 wherein the organic silicate in the coating composition is pre-hydrolyzed in an amount of from about 80% to about 85%.
Claim 8
Dependent Claim
36 words
A process as claimed in claim 1 wherein the citric acid is present in the coating composition in the coating composition in amount of at least about 0.01 gram per cubic centimeter of the coating composition.
Claim 9
Dependent Claim
35 words
A process as claimed in claim 7 wherein the citric acid is present in the coating composition in an amount of from about 0.1 to about 0.2 grams per cubic centimeter of the coating composition.
Claim 10
Dependent Claim
34 words
A process as claimed in claim 1 wherein the solvent of the coating composition is selected from the group consisting of isopropyl alcohol, ethanol, butanol, ethylene glycol, ethyl ether, acetone, pentanone, and methylisobutyl ketone.
Claim 11
Dependent Claim
17 words
A process as claimed in claim 9 wherein the solvent of the coating composition is isopropyl alcohol.
Claim 12
Dependent Claim
21 words
A process as claimed in claim 1 wherein the pH of the coating composition is from about 3.5 to about 4.0.
Claim 13
Dependent Claim
27 words
A process as claimed in claim 1 wherein the top coat is applied over the coating composition within about four hours after application of the coating composition.
Claim 14
Dependent Claim
126 words
A process for dissolving rust on a rusted metal substrate and for protecting the substrate against further corrosion comprising: applying to the rusted metal substrate a non-film forming coating composition having a pH of from about 3.0 to about 4.5 comprising: ethyl silicate in an amount sufficient to provide from about 12% to about 24% by weight silicon dioxide in a cured coating from the coating composition and wherein the ethyl silicate is pre-hydrolyzed in an amount of from about 70% to about 90%; citric acid in an amount of from about 0.1 to about 0.2 grams per cubic centimeter of the coating composition; and a non-aqueous solvent; allowing the coating composition to at least partially cure; and applying a top coat over the coating composition.
Claim 15
Dependent Claim
126 words
A process for dissolving rust on a rusted metal substrate and for protecting the substrate against further corrosion comprising: applying to the rusted metal substrate a non-film forming coating composition having a pH of from about 3.0 to about 4.5 comprising: ethyl silicate in an amount sufficient to provide from about 12% to about 24% by weight silicon dioxide in a cured coating from the coating composition and wherein the ethyl silicate is pre-hydrolyzed in an amount of from about 70% to about 90%; citric acid in an amount of from about 0.1 to about 0.2 grams per cubic centimeter of the coating composition; and a non-aqueous solvent; allowing the coating composition to at least partially cure; and applying a top coat over the coating composition.
Claim 16
Dependent Claim
36 words
A process as claimed in claim 13 wherein the ethyl silicate is present in an amount which provides from about 15% to about 18% by weight silicon dioxide in a cured coating from the coating composition.
Claim 17
Dependent Claim
23 words
A process as claimed in claim 13 wherein the ethyl silicate is pre-hydrolyzed in an amount of from about 80% to about 85%.
Claim 18
Dependent Claim
13 words
A process as claimed in claim 13 wherein the solvent is isopropyl alcohol.
Claim 19
Dependent Claim
21 words
A process as claimed in claim 13 wherein the pH of the coating composition is from about 3.5 to about 4.0.
Claim 20
Dependent Claim
28 words
A process as claimed in claim 13 wherein the top coat is applied over the coating composition within about four hours after the application of the coating composition.
References Cited (Backward Citations)
US3056684A
Cited
US3202517A
Cited
US3562124A
Cited
US3634109A
Cited
US3778280A
Cited
US3660119A
Cited
US3730743A
Cited
US3730746A
Cited
US4086095A
Cited
US3917648A
Cited
US3941609A
Cited
US3849141A
Cited
US3997501A
Cited
US3859101A
Cited
US4086096A
Cited
US4110117A
Cited
US4084971A
Cited
US4208452A
Cited
US4326888A
Cited
US4304707A
Cited
US4239539A
Cited
US4290811A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-02 | 1990-09-01 | 1991-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-02 | 1994-09-01 | 1995-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-02 | 1998-09-01 | 1999-03-03 | $7700.00 | Window Closed / Lapsed |