US3721629A
Expired / Lapsed
US
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Method and composition for removing iron stains from porcelain
Assignee: Dow Chemical Co
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Filing: 1969-05-21
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Granted: 1973-03-20
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Expires: 1989-05-21
Abstract
Abstract A solid or liquid composition for removing iron from stains on hard, smooth surfaces, comprising (a) a sufficient amount of a hydrogen ion source to produce a pH of between about 1.5 and 4.5 under operating conditions; (b) an amount of a chelate agent sufficient to couple the Fe present in the stain, said chelate agent having a positive formation constant for Fe in the pH range of 1.5 to 4.5; (c) a soluble Fe salt in an amount less than equimolar with respect to the chelate agent; and, optionally, agents capable of producing effervescent gases; disinfectants; detergents; dyes; binders; solvents; perfumes; etc.
Inventors
- 👤 R Goodenough
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:34
CPC Classifications
C; C11; C11D; C11D7/00; C11D7/02; C11D7/04; C11D7/10; C11D3/00; C11D3/0005; C11D3/0042; C11D3/02; C11D3/04; C11D3/042; C11D3/046; C11D3/06; C11D3/16; C11D3/26; C11D3/33; C11D7/08; C11D7/16; C11D7/22; C11D7/32; C11D7/3245
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
39 words
The composition of claim 1 wherein the amount of acid is 1.0 to 50.0 weight percent, the amount of Fe salt is 2.0 to 8.0 weight percent, and the amount of chelate agent is 14.0 to 22.0 weight percent.
Claim 2
Dependent Claim
98 words
The composition of claim 1 which comprises: A. 35 to 55 weight percent of component (A) in the form of a solid acid or acid salt; B. 15 to 25 weight percent of component (B); C. 5 to 10 weight percent of component (C); and further, D. 20 to 30 weighT percent of a solid carbonate or bicarbonate of an alkali metal, an alkaline earth metal or ammonium, capable of producing a soluble salt of (A) above in the pH range of 1.5 to 4.5 and which produces, in contact with said H ion source, an effervescent gas.
Claim 3
Dependent Claim
85 words
The composition of claim 1 which comprises: A. 1.5 to 2.5 weight percent of component (A) in the form of a mineral acid; B. 10 to 22 weight percent of component (B); C. 1 to 3.5 weight percent of component (C); D. 3 to 6 weight percent of a reducing agent capable of reducing Fe to Fe in the pH range of about 1.5 to 4.5; E. 30 to 60 weight percent of an aliphatic short chain alcohol of one to about four carbon atoms.
Claim 4
Dependent Claim
27 words
The composition of claim 1 wherein the chelate agent is diethylenetriaminepentaacetic acid; ethylenediaminetetraacetic acid; nitrilotriacetic acid; N-hydroxyethylenediaminetriacetic acid; or the Li, Na, K or NH4 salts thereof.
Claim 5
Dependent Claim
69 words
The composition of claim 3 which comprises: A. 40 to 50 weight percent of an alkali metal bisulfate, alkali metal orthophosphate, alkali metal metaphosphate or sulfamic acid; B. 17 to 21 weight percent of component (B); C. 5 to 7 weight percent of FeSO4.H2O + NaHSO4.H2O; FeSO4. Na2SO4.4H2O; FeCO3; or Fe(SO3-NH2)2; D. 22 to 26 weight percent of Na, K, Li, Mg or ammonium carbonate or bicarbonate, or FeCO3.
Claim 6
Dependent Claim
70 words
The composition of claim 4 which comprises: A. 1.7 to 2.2 weight percent of CHl, H2SO4, HBr or H3PO4; B. 14 to 18 weight percent of component (B); C. 2 to 3 weight percent of ferrous sulfate, chloride, acetate, citrate, bromide or sulfamate; D. 4 to 5 weight percent of sodium hydrosulfite, hydroxylamine hydrochloride or sodium hypophosphite; E. 40 to 50 weight percent of methanol, ethanol, i-propanol, n-propanol or n-butanol.
Claim 7
Dependent Claim
27 words
An improved process for removing Fe from stains on hard surfaces which comprises contacting said stained surface with an effective amount of the composition of claim 1.
Claim 8
Dependent Claim
26 words
An improved process for removing Fe from stains on hard surfaces which comprises contacting said surface with an effective amount of the composition of claim 3.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |