US4225352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anti-corrosive pigment and anti-corrosive aqueous paint
Assignee: Toda Kogyo Corp
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Filing: 1978-06-05
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Granted: 1980-09-30
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Expires: 1998-06-05
Abstract
Abstract An anti-corrosive pigment comprises an ion oxide-calcium oxide sintered composite of an average particle size in a range of 0.7-7 μm, which contains at least 25% by weight of 2CaO.Fe 2 O 3 and has a extremely low water-solubility of calcium content. An anti-corrosive aqueous paints contains the above pigment and has a superior storage stability without causing a gellation.
Inventors
- 👤 Hajime Makino
- 👤 Wataru Shinoda
- 👤 Kazuhiro Yamamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:11
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/22; C09D; C09D5/00; C09D5/08; C09D5/082; C09D5/084; C01; C01P; C01P2002/00; C01P2002/70; C01P2002/72; C01P2004/00; C01P2004/60; C01P2004/61
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
152 words
An anti-corrosive pigment having excellent storage characteristics and substantially free from gelation under storage produced by (a) mixing 57-70% by weight, calculated as Fe 2 O 3 , of an iron compound selected from the group consisting of Fe 2 O 3 , Fe 3 O 4 and FeOOH with 30-43% by weight, calculated as CaO, of a calcium compound selected from the group consisting of CaO, CaCO 3 and Ca(OH) 2 ; (b) calcining the resultant mixture at a temperature in the range of from 1250° to 1400° C. and sufficient to form an iron oxide-calcium oxide sintered composite containing at least 25% by weight of 2CaO-Fe 2 O 3 having a crystal grain size of at least about 0.7 to 20 μm and a calcium oxide solubility of less than 1%; and (c) pulverizing the resultant sintered composite into powder having an average particle size between 0.7 and 7 μm.
Claim 2
Dependent Claim
152 words
An anti-corrosive pigment having excellent storage characteristics and substantially free from gelation under storage produced by (a) mixing 57-70% by weight, calculated as Fe 2 O 3 , of an iron compound selected from the group consisting of Fe 2 O 3 , Fe 3 O 4 and FeOOH with 30-43% by weight, calculated as CaO, of a calcium compound selected from the group consisting of CaO, CaCO 3 and Ca(OH) 2 ; (b) calcining the resultant mixture at a temperature in the range of from 1250° to 1400° C. and sufficient to form an iron oxide-calcium oxide sintered composite containing at least 25% by weight of 2CaO-Fe 2 O 3 having a crystal grain size of at least about 0.7 to 20 μm and a calcium oxide solubility of less than 1%; and (c) pulverizing the resultant sintered composite into powder having an average particle size between 0.7 and 7 μm.
Claim 3
Dependent Claim
38 words
The anti-corrosive pigment of claim 1 wherein the blending ratio for the starting material is 58.5% by weight of the iron compound calculated as Fe 2 O 3 and 41.5% by weight of calcium compound calculated as CaO.
Claim 4
Dependent Claim
21 words
The anti-corrosive pigment of claim 1 wherein the average particle size of the powder is in a range of 1-3 μm.
Claim 5
Dependent Claim
32 words
In an anti-corrosive aqueous paint containing a film-forming resin, an aqueous vehicle and a pigment component containing an anti-corrosive pigment; the improvement comprising, as said anti-corrosive pigment, the product of claim 1.
Claim 6
Dependent Claim
30 words
The anti-corrosive aqueous paint of claim 4 wherein the paint contains at least 10% by weight of 2CaO.Fe 2 O 3 based on the total amounts of pigments contained therein.
Claim 7
Dependent Claim
29 words
The anti-corrosive aqueous paint of claim 5 wherein the ratio of 2CaO.Fe 2 O 3 to the total pigments in the paint is between 20 and 50% by weight.
References Cited (Backward Citations)
US3519386A
Cited
US3904421A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-30 | 1984-03-31 | 1984-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-30 | 1988-03-31 | 1988-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-30 | 1992-03-31 | 1992-09-30 | $7700.00 | Window Closed / Lapsed |